| /* |
| * Copyright (c) Yann Collet, Facebook, Inc. |
| * All rights reserved. |
| * |
| * This source code is licensed under both the BSD-style license (found in the |
| * LICENSE file in the root directory of this source tree) and the GPLv2 (found |
| * in the COPYING file in the root directory of this source tree). |
| * You may select, at your option, one of the above-listed licenses. |
| */ |
| |
| #ifndef ZSTD_H_235446 |
| #define ZSTD_H_235446 |
| |
| /* ====== Dependency ======*/ |
| #include <linux/limits.h> /* INT_MAX */ |
| #include <linux/types.h> /* size_t */ |
| |
| |
| /* ===== ZSTDLIB_API : control library symbols visibility ===== */ |
| #define ZSTDLIB_VISIBILITY |
| #define ZSTDLIB_API ZSTDLIB_VISIBILITY |
| |
| |
| /* ***************************************************************************** |
| Introduction |
| |
| zstd, short for Zstandard, is a fast lossless compression algorithm, targeting |
| real-time compression scenarios at zlib-level and better compression ratios. |
| The zstd compression library provides in-memory compression and decompression |
| functions. |
| |
| The library supports regular compression levels from 1 up to ZSTD_maxCLevel(), |
| which is currently 22. Levels >= 20, labeled `--ultra`, should be used with |
| caution, as they require more memory. The library also offers negative |
| compression levels, which extend the range of speed vs. ratio preferences. |
| The lower the level, the faster the speed (at the cost of compression). |
| |
| Compression can be done in: |
| - a single step (described as Simple API) |
| - a single step, reusing a context (described as Explicit context) |
| - unbounded multiple steps (described as Streaming compression) |
| |
| The compression ratio achievable on small data can be highly improved using |
| a dictionary. Dictionary compression can be performed in: |
| - a single step (described as Simple dictionary API) |
| - a single step, reusing a dictionary (described as Bulk-processing |
| dictionary API) |
| |
| Advanced experimental functions can be accessed using |
| `#define ZSTD_STATIC_LINKING_ONLY` before including zstd.h. |
| |
| Advanced experimental APIs should never be used with a dynamically-linked |
| library. They are not "stable"; their definitions or signatures may change in |
| the future. Only static linking is allowed. |
| *******************************************************************************/ |
| |
| /*------ Version ------*/ |
| #define ZSTD_VERSION_MAJOR 1 |
| #define ZSTD_VERSION_MINOR 4 |
| #define ZSTD_VERSION_RELEASE 10 |
| #define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE) |
| |
| /*! ZSTD_versionNumber() : |
| * Return runtime library version, the value is (MAJOR*100*100 + MINOR*100 + RELEASE). */ |
| ZSTDLIB_API unsigned ZSTD_versionNumber(void); |
| |
| #define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE |
| #define ZSTD_QUOTE(str) #str |
| #define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str) |
| #define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION) |
| |
| /*! ZSTD_versionString() : |
| * Return runtime library version, like "1.4.5". Requires v1.3.0+. */ |
| ZSTDLIB_API const char* ZSTD_versionString(void); |
| |
| /* ************************************* |
| * Default constant |
| ***************************************/ |
| #ifndef ZSTD_CLEVEL_DEFAULT |
| # define ZSTD_CLEVEL_DEFAULT 3 |
| #endif |
| |
| /* ************************************* |
| * Constants |
| ***************************************/ |
| |
| /* All magic numbers are supposed read/written to/from files/memory using little-endian convention */ |
| #define ZSTD_MAGICNUMBER 0xFD2FB528 /* valid since v0.8.0 */ |
| #define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* valid since v0.7.0 */ |
| #define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50 /* all 16 values, from 0x184D2A50 to 0x184D2A5F, signal the beginning of a skippable frame */ |
| #define ZSTD_MAGIC_SKIPPABLE_MASK 0xFFFFFFF0 |
| |
| #define ZSTD_BLOCKSIZELOG_MAX 17 |
| #define ZSTD_BLOCKSIZE_MAX (1<<ZSTD_BLOCKSIZELOG_MAX) |
| |
| |
| |
| /* ************************************* |
| * Simple API |
| ***************************************/ |
| /*! ZSTD_compress() : |
| * Compresses `src` content as a single zstd compressed frame into already allocated `dst`. |
| * Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`. |
| * @return : compressed size written into `dst` (<= `dstCapacity), |
| * or an error code if it fails (which can be tested using ZSTD_isError()). */ |
| ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, |
| int compressionLevel); |
| |
| /*! ZSTD_decompress() : |
| * `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames. |
| * `dstCapacity` is an upper bound of originalSize to regenerate. |
| * If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data. |
| * @return : the number of bytes decompressed into `dst` (<= `dstCapacity`), |
| * or an errorCode if it fails (which can be tested using ZSTD_isError()). */ |
| ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity, |
| const void* src, size_t compressedSize); |
| |
| /*! ZSTD_getFrameContentSize() : requires v1.3.0+ |
| * `src` should point to the start of a ZSTD encoded frame. |
| * `srcSize` must be at least as large as the frame header. |
| * hint : any size >= `ZSTD_frameHeaderSize_max` is large enough. |
| * @return : - decompressed size of `src` frame content, if known |
| * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined |
| * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) |
| * note 1 : a 0 return value means the frame is valid but "empty". |
| * note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode. |
| * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. |
| * In which case, it's necessary to use streaming mode to decompress data. |
| * Optionally, application can rely on some implicit limit, |
| * as ZSTD_decompress() only needs an upper bound of decompressed size. |
| * (For example, data could be necessarily cut into blocks <= 16 KB). |
| * note 3 : decompressed size is always present when compression is completed using single-pass functions, |
| * such as ZSTD_compress(), ZSTD_compressCCtx() ZSTD_compress_usingDict() or ZSTD_compress_usingCDict(). |
| * note 4 : decompressed size can be very large (64-bits value), |
| * potentially larger than what local system can handle as a single memory segment. |
| * In which case, it's necessary to use streaming mode to decompress data. |
| * note 5 : If source is untrusted, decompressed size could be wrong or intentionally modified. |
| * Always ensure return value fits within application's authorized limits. |
| * Each application can set its own limits. |
| * note 6 : This function replaces ZSTD_getDecompressedSize() */ |
| #define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1) |
| #define ZSTD_CONTENTSIZE_ERROR (0ULL - 2) |
| ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize); |
| |
| /*! ZSTD_getDecompressedSize() : |
| * NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize(). |
| * Both functions work the same way, but ZSTD_getDecompressedSize() blends |
| * "empty", "unknown" and "error" results to the same return value (0), |
| * while ZSTD_getFrameContentSize() gives them separate return values. |
| * @return : decompressed size of `src` frame content _if known and not empty_, 0 otherwise. */ |
| ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize); |
| |
| /*! ZSTD_findFrameCompressedSize() : |
| * `src` should point to the start of a ZSTD frame or skippable frame. |
| * `srcSize` must be >= first frame size |
| * @return : the compressed size of the first frame starting at `src`, |
| * suitable to pass as `srcSize` to `ZSTD_decompress` or similar, |
| * or an error code if input is invalid */ |
| ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize); |
| |
| |
| /*====== Helper functions ======*/ |
| #define ZSTD_COMPRESSBOUND(srcSize) ((srcSize) + ((srcSize)>>8) + (((srcSize) < (128<<10)) ? (((128<<10) - (srcSize)) >> 11) /* margin, from 64 to 0 */ : 0)) /* this formula ensures that bound(A) + bound(B) <= bound(A+B) as long as A and B >= 128 KB */ |
| ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case single-pass scenario */ |
| ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */ |
| ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string from an error code */ |
| ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level allowed */ |
| ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */ |
| |
| |
| /* ************************************* |
| * Explicit context |
| ***************************************/ |
| /*= Compression context |
| * When compressing many times, |
| * it is recommended to allocate a context just once, |
| * and re-use it for each successive compression operation. |
| * This will make workload friendlier for system's memory. |
| * Note : re-using context is just a speed / resource optimization. |
| * It doesn't change the compression ratio, which remains identical. |
| * Note 2 : In multi-threaded environments, |
| * use one different context per thread for parallel execution. |
| */ |
| typedef struct ZSTD_CCtx_s ZSTD_CCtx; |
| ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void); |
| ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx); /* accept NULL pointer */ |
| |
| /*! ZSTD_compressCCtx() : |
| * Same as ZSTD_compress(), using an explicit ZSTD_CCtx. |
| * Important : in order to behave similarly to `ZSTD_compress()`, |
| * this function compresses at requested compression level, |
| * __ignoring any other parameter__ . |
| * If any advanced parameter was set using the advanced API, |
| * they will all be reset. Only `compressionLevel` remains. |
| */ |
| ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* cctx, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, |
| int compressionLevel); |
| |
| /*= Decompression context |
| * When decompressing many times, |
| * it is recommended to allocate a context only once, |
| * and re-use it for each successive compression operation. |
| * This will make workload friendlier for system's memory. |
| * Use one context per thread for parallel execution. */ |
| typedef struct ZSTD_DCtx_s ZSTD_DCtx; |
| ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void); |
| ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx); /* accept NULL pointer */ |
| |
| /*! ZSTD_decompressDCtx() : |
| * Same as ZSTD_decompress(), |
| * requires an allocated ZSTD_DCtx. |
| * Compatible with sticky parameters. |
| */ |
| ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize); |
| |
| |
| /* ************************************* |
| * Advanced compression API |
| ***************************************/ |
| |
| /* API design : |
| * Parameters are pushed one by one into an existing context, |
| * using ZSTD_CCtx_set*() functions. |
| * Pushed parameters are sticky : they are valid for next compressed frame, and any subsequent frame. |
| * "sticky" parameters are applicable to `ZSTD_compress2()` and `ZSTD_compressStream*()` ! |
| * __They do not apply to "simple" one-shot variants such as ZSTD_compressCCtx()__ . |
| * |
| * It's possible to reset all parameters to "default" using ZSTD_CCtx_reset(). |
| * |
| * This API supercedes all other "advanced" API entry points in the experimental section. |
| * In the future, we expect to remove from experimental API entry points which are redundant with this API. |
| */ |
| |
| |
| /* Compression strategies, listed from fastest to strongest */ |
| typedef enum { ZSTD_fast=1, |
| ZSTD_dfast=2, |
| ZSTD_greedy=3, |
| ZSTD_lazy=4, |
| ZSTD_lazy2=5, |
| ZSTD_btlazy2=6, |
| ZSTD_btopt=7, |
| ZSTD_btultra=8, |
| ZSTD_btultra2=9 |
| /* note : new strategies _might_ be added in the future. |
| Only the order (from fast to strong) is guaranteed */ |
| } ZSTD_strategy; |
| |
| |
| typedef enum { |
| |
| /* compression parameters |
| * Note: When compressing with a ZSTD_CDict these parameters are superseded |
| * by the parameters used to construct the ZSTD_CDict. |
| * See ZSTD_CCtx_refCDict() for more info (superseded-by-cdict). */ |
| ZSTD_c_compressionLevel=100, /* Set compression parameters according to pre-defined cLevel table. |
| * Note that exact compression parameters are dynamically determined, |
| * depending on both compression level and srcSize (when known). |
| * Default level is ZSTD_CLEVEL_DEFAULT==3. |
| * Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT. |
| * Note 1 : it's possible to pass a negative compression level. |
| * Note 2 : setting a level does not automatically set all other compression parameters |
| * to default. Setting this will however eventually dynamically impact the compression |
| * parameters which have not been manually set. The manually set |
| * ones will 'stick'. */ |
| /* Advanced compression parameters : |
| * It's possible to pin down compression parameters to some specific values. |
| * In which case, these values are no longer dynamically selected by the compressor */ |
| ZSTD_c_windowLog=101, /* Maximum allowed back-reference distance, expressed as power of 2. |
| * This will set a memory budget for streaming decompression, |
| * with larger values requiring more memory |
| * and typically compressing more. |
| * Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX. |
| * Special: value 0 means "use default windowLog". |
| * Note: Using a windowLog greater than ZSTD_WINDOWLOG_LIMIT_DEFAULT |
| * requires explicitly allowing such size at streaming decompression stage. */ |
| ZSTD_c_hashLog=102, /* Size of the initial probe table, as a power of 2. |
| * Resulting memory usage is (1 << (hashLog+2)). |
| * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX. |
| * Larger tables improve compression ratio of strategies <= dFast, |
| * and improve speed of strategies > dFast. |
| * Special: value 0 means "use default hashLog". */ |
| ZSTD_c_chainLog=103, /* Size of the multi-probe search table, as a power of 2. |
| * Resulting memory usage is (1 << (chainLog+2)). |
| * Must be clamped between ZSTD_CHAINLOG_MIN and ZSTD_CHAINLOG_MAX. |
| * Larger tables result in better and slower compression. |
| * This parameter is useless for "fast" strategy. |
| * It's still useful when using "dfast" strategy, |
| * in which case it defines a secondary probe table. |
| * Special: value 0 means "use default chainLog". */ |
| ZSTD_c_searchLog=104, /* Number of search attempts, as a power of 2. |
| * More attempts result in better and slower compression. |
| * This parameter is useless for "fast" and "dFast" strategies. |
| * Special: value 0 means "use default searchLog". */ |
| ZSTD_c_minMatch=105, /* Minimum size of searched matches. |
| * Note that Zstandard can still find matches of smaller size, |
| * it just tweaks its search algorithm to look for this size and larger. |
| * Larger values increase compression and decompression speed, but decrease ratio. |
| * Must be clamped between ZSTD_MINMATCH_MIN and ZSTD_MINMATCH_MAX. |
| * Note that currently, for all strategies < btopt, effective minimum is 4. |
| * , for all strategies > fast, effective maximum is 6. |
| * Special: value 0 means "use default minMatchLength". */ |
| ZSTD_c_targetLength=106, /* Impact of this field depends on strategy. |
| * For strategies btopt, btultra & btultra2: |
| * Length of Match considered "good enough" to stop search. |
| * Larger values make compression stronger, and slower. |
| * For strategy fast: |
| * Distance between match sampling. |
| * Larger values make compression faster, and weaker. |
| * Special: value 0 means "use default targetLength". */ |
| ZSTD_c_strategy=107, /* See ZSTD_strategy enum definition. |
| * The higher the value of selected strategy, the more complex it is, |
| * resulting in stronger and slower compression. |
| * Special: value 0 means "use default strategy". */ |
| |
| /* LDM mode parameters */ |
| ZSTD_c_enableLongDistanceMatching=160, /* Enable long distance matching. |
| * This parameter is designed to improve compression ratio |
| * for large inputs, by finding large matches at long distance. |
| * It increases memory usage and window size. |
| * Note: enabling this parameter increases default ZSTD_c_windowLog to 128 MB |
| * except when expressly set to a different value. |
| * Note: will be enabled by default if ZSTD_c_windowLog >= 128 MB and |
| * compression strategy >= ZSTD_btopt (== compression level 16+) */ |
| ZSTD_c_ldmHashLog=161, /* Size of the table for long distance matching, as a power of 2. |
| * Larger values increase memory usage and compression ratio, |
| * but decrease compression speed. |
| * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX |
| * default: windowlog - 7. |
| * Special: value 0 means "automatically determine hashlog". */ |
| ZSTD_c_ldmMinMatch=162, /* Minimum match size for long distance matcher. |
| * Larger/too small values usually decrease compression ratio. |
| * Must be clamped between ZSTD_LDM_MINMATCH_MIN and ZSTD_LDM_MINMATCH_MAX. |
| * Special: value 0 means "use default value" (default: 64). */ |
| ZSTD_c_ldmBucketSizeLog=163, /* Log size of each bucket in the LDM hash table for collision resolution. |
| * Larger values improve collision resolution but decrease compression speed. |
| * The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX. |
| * Special: value 0 means "use default value" (default: 3). */ |
| ZSTD_c_ldmHashRateLog=164, /* Frequency of inserting/looking up entries into the LDM hash table. |
| * Must be clamped between 0 and (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN). |
| * Default is MAX(0, (windowLog - ldmHashLog)), optimizing hash table usage. |
| * Larger values improve compression speed. |
| * Deviating far from default value will likely result in a compression ratio decrease. |
| * Special: value 0 means "automatically determine hashRateLog". */ |
| |
| /* frame parameters */ |
| ZSTD_c_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1) |
| * Content size must be known at the beginning of compression. |
| * This is automatically the case when using ZSTD_compress2(), |
| * For streaming scenarios, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */ |
| ZSTD_c_checksumFlag=201, /* A 32-bits checksum of content is written at end of frame (default:0) */ |
| ZSTD_c_dictIDFlag=202, /* When applicable, dictionary's ID is written into frame header (default:1) */ |
| |
| /* multi-threading parameters */ |
| /* These parameters are only active if multi-threading is enabled (compiled with build macro ZSTD_MULTITHREAD). |
| * Otherwise, trying to set any other value than default (0) will be a no-op and return an error. |
| * In a situation where it's unknown if the linked library supports multi-threading or not, |
| * setting ZSTD_c_nbWorkers to any value >= 1 and consulting the return value provides a quick way to check this property. |
| */ |
| ZSTD_c_nbWorkers=400, /* Select how many threads will be spawned to compress in parallel. |
| * When nbWorkers >= 1, triggers asynchronous mode when invoking ZSTD_compressStream*() : |
| * ZSTD_compressStream*() consumes input and flush output if possible, but immediately gives back control to caller, |
| * while compression is performed in parallel, within worker thread(s). |
| * (note : a strong exception to this rule is when first invocation of ZSTD_compressStream2() sets ZSTD_e_end : |
| * in which case, ZSTD_compressStream2() delegates to ZSTD_compress2(), which is always a blocking call). |
| * More workers improve speed, but also increase memory usage. |
| * Default value is `0`, aka "single-threaded mode" : no worker is spawned, |
| * compression is performed inside Caller's thread, and all invocations are blocking */ |
| ZSTD_c_jobSize=401, /* Size of a compression job. This value is enforced only when nbWorkers >= 1. |
| * Each compression job is completed in parallel, so this value can indirectly impact the nb of active threads. |
| * 0 means default, which is dynamically determined based on compression parameters. |
| * Job size must be a minimum of overlap size, or 1 MB, whichever is largest. |
| * The minimum size is automatically and transparently enforced. */ |
| ZSTD_c_overlapLog=402, /* Control the overlap size, as a fraction of window size. |
| * The overlap size is an amount of data reloaded from previous job at the beginning of a new job. |
| * It helps preserve compression ratio, while each job is compressed in parallel. |
| * This value is enforced only when nbWorkers >= 1. |
| * Larger values increase compression ratio, but decrease speed. |
| * Possible values range from 0 to 9 : |
| * - 0 means "default" : value will be determined by the library, depending on strategy |
| * - 1 means "no overlap" |
| * - 9 means "full overlap", using a full window size. |
| * Each intermediate rank increases/decreases load size by a factor 2 : |
| * 9: full window; 8: w/2; 7: w/4; 6: w/8; 5:w/16; 4: w/32; 3:w/64; 2:w/128; 1:no overlap; 0:default |
| * default value varies between 6 and 9, depending on strategy */ |
| |
| /* note : additional experimental parameters are also available |
| * within the experimental section of the API. |
| * At the time of this writing, they include : |
| * ZSTD_c_rsyncable |
| * ZSTD_c_format |
| * ZSTD_c_forceMaxWindow |
| * ZSTD_c_forceAttachDict |
| * ZSTD_c_literalCompressionMode |
| * ZSTD_c_targetCBlockSize |
| * ZSTD_c_srcSizeHint |
| * ZSTD_c_enableDedicatedDictSearch |
| * ZSTD_c_stableInBuffer |
| * ZSTD_c_stableOutBuffer |
| * ZSTD_c_blockDelimiters |
| * ZSTD_c_validateSequences |
| * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. |
| * note : never ever use experimentalParam? names directly; |
| * also, the enums values themselves are unstable and can still change. |
| */ |
| ZSTD_c_experimentalParam1=500, |
| ZSTD_c_experimentalParam2=10, |
| ZSTD_c_experimentalParam3=1000, |
| ZSTD_c_experimentalParam4=1001, |
| ZSTD_c_experimentalParam5=1002, |
| ZSTD_c_experimentalParam6=1003, |
| ZSTD_c_experimentalParam7=1004, |
| ZSTD_c_experimentalParam8=1005, |
| ZSTD_c_experimentalParam9=1006, |
| ZSTD_c_experimentalParam10=1007, |
| ZSTD_c_experimentalParam11=1008, |
| ZSTD_c_experimentalParam12=1009 |
| } ZSTD_cParameter; |
| |
| typedef struct { |
| size_t error; |
| int lowerBound; |
| int upperBound; |
| } ZSTD_bounds; |
| |
| /*! ZSTD_cParam_getBounds() : |
| * All parameters must belong to an interval with lower and upper bounds, |
| * otherwise they will either trigger an error or be automatically clamped. |
| * @return : a structure, ZSTD_bounds, which contains |
| * - an error status field, which must be tested using ZSTD_isError() |
| * - lower and upper bounds, both inclusive |
| */ |
| ZSTDLIB_API ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter cParam); |
| |
| /*! ZSTD_CCtx_setParameter() : |
| * Set one compression parameter, selected by enum ZSTD_cParameter. |
| * All parameters have valid bounds. Bounds can be queried using ZSTD_cParam_getBounds(). |
| * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). |
| * Setting a parameter is generally only possible during frame initialization (before starting compression). |
| * Exception : when using multi-threading mode (nbWorkers >= 1), |
| * the following parameters can be updated _during_ compression (within same frame): |
| * => compressionLevel, hashLog, chainLog, searchLog, minMatch, targetLength and strategy. |
| * new parameters will be active for next job only (after a flush()). |
| * @return : an error code (which can be tested using ZSTD_isError()). |
| */ |
| ZSTDLIB_API size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value); |
| |
| /*! ZSTD_CCtx_setPledgedSrcSize() : |
| * Total input data size to be compressed as a single frame. |
| * Value will be written in frame header, unless if explicitly forbidden using ZSTD_c_contentSizeFlag. |
| * This value will also be controlled at end of frame, and trigger an error if not respected. |
| * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
| * Note 1 : pledgedSrcSize==0 actually means zero, aka an empty frame. |
| * In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN. |
| * ZSTD_CONTENTSIZE_UNKNOWN is default value for any new frame. |
| * Note 2 : pledgedSrcSize is only valid once, for the next frame. |
| * It's discarded at the end of the frame, and replaced by ZSTD_CONTENTSIZE_UNKNOWN. |
| * Note 3 : Whenever all input data is provided and consumed in a single round, |
| * for example with ZSTD_compress2(), |
| * or invoking immediately ZSTD_compressStream2(,,,ZSTD_e_end), |
| * this value is automatically overridden by srcSize instead. |
| */ |
| ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize); |
| |
| typedef enum { |
| ZSTD_reset_session_only = 1, |
| ZSTD_reset_parameters = 2, |
| ZSTD_reset_session_and_parameters = 3 |
| } ZSTD_ResetDirective; |
| |
| /*! ZSTD_CCtx_reset() : |
| * There are 2 different things that can be reset, independently or jointly : |
| * - The session : will stop compressing current frame, and make CCtx ready to start a new one. |
| * Useful after an error, or to interrupt any ongoing compression. |
| * Any internal data not yet flushed is cancelled. |
| * Compression parameters and dictionary remain unchanged. |
| * They will be used to compress next frame. |
| * Resetting session never fails. |
| * - The parameters : changes all parameters back to "default". |
| * This removes any reference to any dictionary too. |
| * Parameters can only be changed between 2 sessions (i.e. no compression is currently ongoing) |
| * otherwise the reset fails, and function returns an error value (which can be tested using ZSTD_isError()) |
| * - Both : similar to resetting the session, followed by resetting parameters. |
| */ |
| ZSTDLIB_API size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset); |
| |
| /*! ZSTD_compress2() : |
| * Behave the same as ZSTD_compressCCtx(), but compression parameters are set using the advanced API. |
| * ZSTD_compress2() always starts a new frame. |
| * Should cctx hold data from a previously unfinished frame, everything about it is forgotten. |
| * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() |
| * - The function is always blocking, returns when compression is completed. |
| * Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`. |
| * @return : compressed size written into `dst` (<= `dstCapacity), |
| * or an error code if it fails (which can be tested using ZSTD_isError()). |
| */ |
| ZSTDLIB_API size_t ZSTD_compress2( ZSTD_CCtx* cctx, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize); |
| |
| |
| /* ************************************* |
| * Advanced decompression API |
| ***************************************/ |
| |
| /* The advanced API pushes parameters one by one into an existing DCtx context. |
| * Parameters are sticky, and remain valid for all following frames |
| * using the same DCtx context. |
| * It's possible to reset parameters to default values using ZSTD_DCtx_reset(). |
| * Note : This API is compatible with existing ZSTD_decompressDCtx() and ZSTD_decompressStream(). |
| * Therefore, no new decompression function is necessary. |
| */ |
| |
| typedef enum { |
| |
| ZSTD_d_windowLogMax=100, /* Select a size limit (in power of 2) beyond which |
| * the streaming API will refuse to allocate memory buffer |
| * in order to protect the host from unreasonable memory requirements. |
| * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode. |
| * By default, a decompression context accepts window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT). |
| * Special: value 0 means "use default maximum windowLog". */ |
| |
| /* note : additional experimental parameters are also available |
| * within the experimental section of the API. |
| * At the time of this writing, they include : |
| * ZSTD_d_format |
| * ZSTD_d_stableOutBuffer |
| * ZSTD_d_forceIgnoreChecksum |
| * ZSTD_d_refMultipleDDicts |
| * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. |
| * note : never ever use experimentalParam? names directly |
| */ |
| ZSTD_d_experimentalParam1=1000, |
| ZSTD_d_experimentalParam2=1001, |
| ZSTD_d_experimentalParam3=1002, |
| ZSTD_d_experimentalParam4=1003 |
| |
| } ZSTD_dParameter; |
| |
| /*! ZSTD_dParam_getBounds() : |
| * All parameters must belong to an interval with lower and upper bounds, |
| * otherwise they will either trigger an error or be automatically clamped. |
| * @return : a structure, ZSTD_bounds, which contains |
| * - an error status field, which must be tested using ZSTD_isError() |
| * - both lower and upper bounds, inclusive |
| */ |
| ZSTDLIB_API ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam); |
| |
| /*! ZSTD_DCtx_setParameter() : |
| * Set one compression parameter, selected by enum ZSTD_dParameter. |
| * All parameters have valid bounds. Bounds can be queried using ZSTD_dParam_getBounds(). |
| * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). |
| * Setting a parameter is only possible during frame initialization (before starting decompression). |
| * @return : 0, or an error code (which can be tested using ZSTD_isError()). |
| */ |
| ZSTDLIB_API size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int value); |
| |
| /*! ZSTD_DCtx_reset() : |
| * Return a DCtx to clean state. |
| * Session and parameters can be reset jointly or separately. |
| * Parameters can only be reset when no active frame is being decompressed. |
| * @return : 0, or an error code, which can be tested with ZSTD_isError() |
| */ |
| ZSTDLIB_API size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset); |
| |
| |
| /* ************************** |
| * Streaming |
| ****************************/ |
| |
| typedef struct ZSTD_inBuffer_s { |
| const void* src; /*< start of input buffer */ |
| size_t size; /*< size of input buffer */ |
| size_t pos; /*< position where reading stopped. Will be updated. Necessarily 0 <= pos <= size */ |
| } ZSTD_inBuffer; |
| |
| typedef struct ZSTD_outBuffer_s { |
| void* dst; /*< start of output buffer */ |
| size_t size; /*< size of output buffer */ |
| size_t pos; /*< position where writing stopped. Will be updated. Necessarily 0 <= pos <= size */ |
| } ZSTD_outBuffer; |
| |
| |
| |
| /*-*********************************************************************** |
| * Streaming compression - HowTo |
| * |
| * A ZSTD_CStream object is required to track streaming operation. |
| * Use ZSTD_createCStream() and ZSTD_freeCStream() to create/release resources. |
| * ZSTD_CStream objects can be reused multiple times on consecutive compression operations. |
| * It is recommended to re-use ZSTD_CStream since it will play nicer with system's memory, by re-using already allocated memory. |
| * |
| * For parallel execution, use one separate ZSTD_CStream per thread. |
| * |
| * note : since v1.3.0, ZSTD_CStream and ZSTD_CCtx are the same thing. |
| * |
| * Parameters are sticky : when starting a new compression on the same context, |
| * it will re-use the same sticky parameters as previous compression session. |
| * When in doubt, it's recommended to fully initialize the context before usage. |
| * Use ZSTD_CCtx_reset() to reset the context and ZSTD_CCtx_setParameter(), |
| * ZSTD_CCtx_setPledgedSrcSize(), or ZSTD_CCtx_loadDictionary() and friends to |
| * set more specific parameters, the pledged source size, or load a dictionary. |
| * |
| * Use ZSTD_compressStream2() with ZSTD_e_continue as many times as necessary to |
| * consume input stream. The function will automatically update both `pos` |
| * fields within `input` and `output`. |
| * Note that the function may not consume the entire input, for example, because |
| * the output buffer is already full, in which case `input.pos < input.size`. |
| * The caller must check if input has been entirely consumed. |
| * If not, the caller must make some room to receive more compressed data, |
| * and then present again remaining input data. |
| * note: ZSTD_e_continue is guaranteed to make some forward progress when called, |
| * but doesn't guarantee maximal forward progress. This is especially relevant |
| * when compressing with multiple threads. The call won't block if it can |
| * consume some input, but if it can't it will wait for some, but not all, |
| * output to be flushed. |
| * @return : provides a minimum amount of data remaining to be flushed from internal buffers |
| * or an error code, which can be tested using ZSTD_isError(). |
| * |
| * At any moment, it's possible to flush whatever data might remain stuck within internal buffer, |
| * using ZSTD_compressStream2() with ZSTD_e_flush. `output->pos` will be updated. |
| * Note that, if `output->size` is too small, a single invocation with ZSTD_e_flush might not be enough (return code > 0). |
| * In which case, make some room to receive more compressed data, and call again ZSTD_compressStream2() with ZSTD_e_flush. |
| * You must continue calling ZSTD_compressStream2() with ZSTD_e_flush until it returns 0, at which point you can change the |
| * operation. |
| * note: ZSTD_e_flush will flush as much output as possible, meaning when compressing with multiple threads, it will |
| * block until the flush is complete or the output buffer is full. |
| * @return : 0 if internal buffers are entirely flushed, |
| * >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), |
| * or an error code, which can be tested using ZSTD_isError(). |
| * |
| * Calling ZSTD_compressStream2() with ZSTD_e_end instructs to finish a frame. |
| * It will perform a flush and write frame epilogue. |
| * The epilogue is required for decoders to consider a frame completed. |
| * flush operation is the same, and follows same rules as calling ZSTD_compressStream2() with ZSTD_e_flush. |
| * You must continue calling ZSTD_compressStream2() with ZSTD_e_end until it returns 0, at which point you are free to |
| * start a new frame. |
| * note: ZSTD_e_end will flush as much output as possible, meaning when compressing with multiple threads, it will |
| * block until the flush is complete or the output buffer is full. |
| * @return : 0 if frame fully completed and fully flushed, |
| * >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), |
| * or an error code, which can be tested using ZSTD_isError(). |
| * |
| * *******************************************************************/ |
| |
| typedef ZSTD_CCtx ZSTD_CStream; /*< CCtx and CStream are now effectively same object (>= v1.3.0) */ |
| /* Continue to distinguish them for compatibility with older versions <= v1.2.0 */ |
| /*===== ZSTD_CStream management functions =====*/ |
| ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void); |
| ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs); /* accept NULL pointer */ |
| |
| /*===== Streaming compression functions =====*/ |
| typedef enum { |
| ZSTD_e_continue=0, /* collect more data, encoder decides when to output compressed result, for optimal compression ratio */ |
| ZSTD_e_flush=1, /* flush any data provided so far, |
| * it creates (at least) one new block, that can be decoded immediately on reception; |
| * frame will continue: any future data can still reference previously compressed data, improving compression. |
| * note : multithreaded compression will block to flush as much output as possible. */ |
| ZSTD_e_end=2 /* flush any remaining data _and_ close current frame. |
| * note that frame is only closed after compressed data is fully flushed (return value == 0). |
| * After that point, any additional data starts a new frame. |
| * note : each frame is independent (does not reference any content from previous frame). |
| : note : multithreaded compression will block to flush as much output as possible. */ |
| } ZSTD_EndDirective; |
| |
| /*! ZSTD_compressStream2() : |
| * Behaves about the same as ZSTD_compressStream, with additional control on end directive. |
| * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() |
| * - Compression parameters cannot be changed once compression is started (save a list of exceptions in multi-threading mode) |
| * - output->pos must be <= dstCapacity, input->pos must be <= srcSize |
| * - output->pos and input->pos will be updated. They are guaranteed to remain below their respective limit. |
| * - endOp must be a valid directive |
| * - When nbWorkers==0 (default), function is blocking : it completes its job before returning to caller. |
| * - When nbWorkers>=1, function is non-blocking : it copies a portion of input, distributes jobs to internal worker threads, flush to output whatever is available, |
| * and then immediately returns, just indicating that there is some data remaining to be flushed. |
| * The function nonetheless guarantees forward progress : it will return only after it reads or write at least 1+ byte. |
| * - Exception : if the first call requests a ZSTD_e_end directive and provides enough dstCapacity, the function delegates to ZSTD_compress2() which is always blocking. |
| * - @return provides a minimum amount of data remaining to be flushed from internal buffers |
| * or an error code, which can be tested using ZSTD_isError(). |
| * if @return != 0, flush is not fully completed, there is still some data left within internal buffers. |
| * This is useful for ZSTD_e_flush, since in this case more flushes are necessary to empty all buffers. |
| * For ZSTD_e_end, @return == 0 when internal buffers are fully flushed and frame is completed. |
| * - after a ZSTD_e_end directive, if internal buffer is not fully flushed (@return != 0), |
| * only ZSTD_e_end or ZSTD_e_flush operations are allowed. |
| * Before starting a new compression job, or changing compression parameters, |
| * it is required to fully flush internal buffers. |
| */ |
| ZSTDLIB_API size_t ZSTD_compressStream2( ZSTD_CCtx* cctx, |
| ZSTD_outBuffer* output, |
| ZSTD_inBuffer* input, |
| ZSTD_EndDirective endOp); |
| |
| |
| /* These buffer sizes are softly recommended. |
| * They are not required : ZSTD_compressStream*() happily accepts any buffer size, for both input and output. |
| * Respecting the recommended size just makes it a bit easier for ZSTD_compressStream*(), |
| * reducing the amount of memory shuffling and buffering, resulting in minor performance savings. |
| * |
| * However, note that these recommendations are from the perspective of a C caller program. |
| * If the streaming interface is invoked from some other language, |
| * especially managed ones such as Java or Go, through a foreign function interface such as jni or cgo, |
| * a major performance rule is to reduce crossing such interface to an absolute minimum. |
| * It's not rare that performance ends being spent more into the interface, rather than compression itself. |
| * In which cases, prefer using large buffers, as large as practical, |
| * for both input and output, to reduce the nb of roundtrips. |
| */ |
| ZSTDLIB_API size_t ZSTD_CStreamInSize(void); /*< recommended size for input buffer */ |
| ZSTDLIB_API size_t ZSTD_CStreamOutSize(void); /*< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block. */ |
| |
| |
| /* ***************************************************************************** |
| * This following is a legacy streaming API. |
| * It can be replaced by ZSTD_CCtx_reset() and ZSTD_compressStream2(). |
| * It is redundant, but remains fully supported. |
| * Advanced parameters and dictionary compression can only be used through the |
| * new API. |
| ******************************************************************************/ |
| |
| /*! |
| * Equivalent to: |
| * |
| * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); |
| * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any) |
| * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); |
| */ |
| ZSTDLIB_API size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel); |
| /*! |
| * Alternative for ZSTD_compressStream2(zcs, output, input, ZSTD_e_continue). |
| * NOTE: The return value is different. ZSTD_compressStream() returns a hint for |
| * the next read size (if non-zero and not an error). ZSTD_compressStream2() |
| * returns the minimum nb of bytes left to flush (if non-zero and not an error). |
| */ |
| ZSTDLIB_API size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input); |
| /*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_flush). */ |
| ZSTDLIB_API size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); |
| /*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_end). */ |
| ZSTDLIB_API size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); |
| |
| |
| /*-*************************************************************************** |
| * Streaming decompression - HowTo |
| * |
| * A ZSTD_DStream object is required to track streaming operations. |
| * Use ZSTD_createDStream() and ZSTD_freeDStream() to create/release resources. |
| * ZSTD_DStream objects can be re-used multiple times. |
| * |
| * Use ZSTD_initDStream() to start a new decompression operation. |
| * @return : recommended first input size |
| * Alternatively, use advanced API to set specific properties. |
| * |
| * Use ZSTD_decompressStream() repetitively to consume your input. |
| * The function will update both `pos` fields. |
| * If `input.pos < input.size`, some input has not been consumed. |
| * It's up to the caller to present again remaining data. |
| * The function tries to flush all data decoded immediately, respecting output buffer size. |
| * If `output.pos < output.size`, decoder has flushed everything it could. |
| * But if `output.pos == output.size`, there might be some data left within internal buffers., |
| * In which case, call ZSTD_decompressStream() again to flush whatever remains in the buffer. |
| * Note : with no additional input provided, amount of data flushed is necessarily <= ZSTD_BLOCKSIZE_MAX. |
| * @return : 0 when a frame is completely decoded and fully flushed, |
| * or an error code, which can be tested using ZSTD_isError(), |
| * or any other value > 0, which means there is still some decoding or flushing to do to complete current frame : |
| * the return value is a suggested next input size (just a hint for better latency) |
| * that will never request more than the remaining frame size. |
| * *******************************************************************************/ |
| |
| typedef ZSTD_DCtx ZSTD_DStream; /*< DCtx and DStream are now effectively same object (>= v1.3.0) */ |
| /* For compatibility with versions <= v1.2.0, prefer differentiating them. */ |
| /*===== ZSTD_DStream management functions =====*/ |
| ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void); |
| ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds); /* accept NULL pointer */ |
| |
| /*===== Streaming decompression functions =====*/ |
| |
| /* This function is redundant with the advanced API and equivalent to: |
| * |
| * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); |
| * ZSTD_DCtx_refDDict(zds, NULL); |
| */ |
| ZSTDLIB_API size_t ZSTD_initDStream(ZSTD_DStream* zds); |
| |
| ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input); |
| |
| ZSTDLIB_API size_t ZSTD_DStreamInSize(void); /*!< recommended size for input buffer */ |
| ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */ |
| |
| |
| /* ************************ |
| * Simple dictionary API |
| ***************************/ |
| /*! ZSTD_compress_usingDict() : |
| * Compression at an explicit compression level using a Dictionary. |
| * A dictionary can be any arbitrary data segment (also called a prefix), |
| * or a buffer with specified information (see dictBuilder/zdict.h). |
| * Note : This function loads the dictionary, resulting in significant startup delay. |
| * It's intended for a dictionary used only once. |
| * Note 2 : When `dict == NULL || dictSize < 8` no dictionary is used. */ |
| ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, |
| const void* dict,size_t dictSize, |
| int compressionLevel); |
| |
| /*! ZSTD_decompress_usingDict() : |
| * Decompression using a known Dictionary. |
| * Dictionary must be identical to the one used during compression. |
| * Note : This function loads the dictionary, resulting in significant startup delay. |
| * It's intended for a dictionary used only once. |
| * Note : When `dict == NULL || dictSize < 8` no dictionary is used. */ |
| ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, |
| const void* dict,size_t dictSize); |
| |
| |
| /* ********************************* |
| * Bulk processing dictionary API |
| **********************************/ |
| typedef struct ZSTD_CDict_s ZSTD_CDict; |
| |
| /*! ZSTD_createCDict() : |
| * When compressing multiple messages or blocks using the same dictionary, |
| * it's recommended to digest the dictionary only once, since it's a costly operation. |
| * ZSTD_createCDict() will create a state from digesting a dictionary. |
| * The resulting state can be used for future compression operations with very limited startup cost. |
| * ZSTD_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only. |
| * @dictBuffer can be released after ZSTD_CDict creation, because its content is copied within CDict. |
| * Note 1 : Consider experimental function `ZSTD_createCDict_byReference()` if you prefer to not duplicate @dictBuffer content. |
| * Note 2 : A ZSTD_CDict can be created from an empty @dictBuffer, |
| * in which case the only thing that it transports is the @compressionLevel. |
| * This can be useful in a pipeline featuring ZSTD_compress_usingCDict() exclusively, |
| * expecting a ZSTD_CDict parameter with any data, including those without a known dictionary. */ |
| ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize, |
| int compressionLevel); |
| |
| /*! ZSTD_freeCDict() : |
| * Function frees memory allocated by ZSTD_createCDict(). |
| * If a NULL pointer is passed, no operation is performed. */ |
| ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict); |
| |
| /*! ZSTD_compress_usingCDict() : |
| * Compression using a digested Dictionary. |
| * Recommended when same dictionary is used multiple times. |
| * Note : compression level is _decided at dictionary creation time_, |
| * and frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no) */ |
| ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, |
| const ZSTD_CDict* cdict); |
| |
| |
| typedef struct ZSTD_DDict_s ZSTD_DDict; |
| |
| /*! ZSTD_createDDict() : |
| * Create a digested dictionary, ready to start decompression operation without startup delay. |
| * dictBuffer can be released after DDict creation, as its content is copied inside DDict. */ |
| ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize); |
| |
| /*! ZSTD_freeDDict() : |
| * Function frees memory allocated with ZSTD_createDDict() |
| * If a NULL pointer is passed, no operation is performed. */ |
| ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict); |
| |
| /*! ZSTD_decompress_usingDDict() : |
| * Decompression using a digested Dictionary. |
| * Recommended when same dictionary is used multiple times. */ |
| ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, |
| const ZSTD_DDict* ddict); |
| |
| |
| /* ****************************** |
| * Dictionary helper functions |
| *******************************/ |
| |
| /*! ZSTD_getDictID_fromDict() : |
| * Provides the dictID stored within dictionary. |
| * if @return == 0, the dictionary is not conformant with Zstandard specification. |
| * It can still be loaded, but as a content-only dictionary. */ |
| ZSTDLIB_API unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize); |
| |
| /*! ZSTD_getDictID_fromDDict() : |
| * Provides the dictID of the dictionary loaded into `ddict`. |
| * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty. |
| * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */ |
| ZSTDLIB_API unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict); |
| |
| /*! ZSTD_getDictID_fromFrame() : |
| * Provides the dictID required to decompressed the frame stored within `src`. |
| * If @return == 0, the dictID could not be decoded. |
| * This could for one of the following reasons : |
| * - The frame does not require a dictionary to be decoded (most common case). |
| * - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden information. |
| * Note : this use case also happens when using a non-conformant dictionary. |
| * - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`). |
| * - This is not a Zstandard frame. |
| * When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code. */ |
| ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize); |
| |
| |
| /* ***************************************************************************** |
| * Advanced dictionary and prefix API |
| * |
| * This API allows dictionaries to be used with ZSTD_compress2(), |
| * ZSTD_compressStream2(), and ZSTD_decompress(). Dictionaries are sticky, and |
| * only reset with the context is reset with ZSTD_reset_parameters or |
| * ZSTD_reset_session_and_parameters. Prefixes are single-use. |
| ******************************************************************************/ |
| |
| |
| /*! ZSTD_CCtx_loadDictionary() : |
| * Create an internal CDict from `dict` buffer. |
| * Decompression will have to use same dictionary. |
| * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
| * Special: Loading a NULL (or 0-size) dictionary invalidates previous dictionary, |
| * meaning "return to no-dictionary mode". |
| * Note 1 : Dictionary is sticky, it will be used for all future compressed frames. |
| * To return to "no-dictionary" situation, load a NULL dictionary (or reset parameters). |
| * Note 2 : Loading a dictionary involves building tables. |
| * It's also a CPU consuming operation, with non-negligible impact on latency. |
| * Tables are dependent on compression parameters, and for this reason, |
| * compression parameters can no longer be changed after loading a dictionary. |
| * Note 3 :`dict` content will be copied internally. |
| * Use experimental ZSTD_CCtx_loadDictionary_byReference() to reference content instead. |
| * In such a case, dictionary buffer must outlive its users. |
| * Note 4 : Use ZSTD_CCtx_loadDictionary_advanced() |
| * to precisely select how dictionary content must be interpreted. */ |
| ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); |
| |
| /*! ZSTD_CCtx_refCDict() : |
| * Reference a prepared dictionary, to be used for all next compressed frames. |
| * Note that compression parameters are enforced from within CDict, |
| * and supersede any compression parameter previously set within CCtx. |
| * The parameters ignored are labelled as "superseded-by-cdict" in the ZSTD_cParameter enum docs. |
| * The ignored parameters will be used again if the CCtx is returned to no-dictionary mode. |
| * The dictionary will remain valid for future compressed frames using same CCtx. |
| * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
| * Special : Referencing a NULL CDict means "return to no-dictionary mode". |
| * Note 1 : Currently, only one dictionary can be managed. |
| * Referencing a new dictionary effectively "discards" any previous one. |
| * Note 2 : CDict is just referenced, its lifetime must outlive its usage within CCtx. */ |
| ZSTDLIB_API size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); |
| |
| /*! ZSTD_CCtx_refPrefix() : |
| * Reference a prefix (single-usage dictionary) for next compressed frame. |
| * A prefix is **only used once**. Tables are discarded at end of frame (ZSTD_e_end). |
| * Decompression will need same prefix to properly regenerate data. |
| * Compressing with a prefix is similar in outcome as performing a diff and compressing it, |
| * but performs much faster, especially during decompression (compression speed is tunable with compression level). |
| * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
| * Special: Adding any prefix (including NULL) invalidates any previous prefix or dictionary |
| * Note 1 : Prefix buffer is referenced. It **must** outlive compression. |
| * Its content must remain unmodified during compression. |
| * Note 2 : If the intention is to diff some large src data blob with some prior version of itself, |
| * ensure that the window size is large enough to contain the entire source. |
| * See ZSTD_c_windowLog. |
| * Note 3 : Referencing a prefix involves building tables, which are dependent on compression parameters. |
| * It's a CPU consuming operation, with non-negligible impact on latency. |
| * If there is a need to use the same prefix multiple times, consider loadDictionary instead. |
| * Note 4 : By default, the prefix is interpreted as raw content (ZSTD_dct_rawContent). |
| * Use experimental ZSTD_CCtx_refPrefix_advanced() to alter dictionary interpretation. */ |
| ZSTDLIB_API size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, |
| const void* prefix, size_t prefixSize); |
| |
| /*! ZSTD_DCtx_loadDictionary() : |
| * Create an internal DDict from dict buffer, |
| * to be used to decompress next frames. |
| * The dictionary remains valid for all future frames, until explicitly invalidated. |
| * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
| * Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary, |
| * meaning "return to no-dictionary mode". |
| * Note 1 : Loading a dictionary involves building tables, |
| * which has a non-negligible impact on CPU usage and latency. |
| * It's recommended to "load once, use many times", to amortize the cost |
| * Note 2 :`dict` content will be copied internally, so `dict` can be released after loading. |
| * Use ZSTD_DCtx_loadDictionary_byReference() to reference dictionary content instead. |
| * Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to take control of |
| * how dictionary content is loaded and interpreted. |
| */ |
| ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); |
| |
| /*! ZSTD_DCtx_refDDict() : |
| * Reference a prepared dictionary, to be used to decompress next frames. |
| * The dictionary remains active for decompression of future frames using same DCtx. |
| * |
| * If called with ZSTD_d_refMultipleDDicts enabled, repeated calls of this function |
| * will store the DDict references in a table, and the DDict used for decompression |
| * will be determined at decompression time, as per the dict ID in the frame. |
| * The memory for the table is allocated on the first call to refDDict, and can be |
| * freed with ZSTD_freeDCtx(). |
| * |
| * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
| * Note 1 : Currently, only one dictionary can be managed. |
| * Referencing a new dictionary effectively "discards" any previous one. |
| * Special: referencing a NULL DDict means "return to no-dictionary mode". |
| * Note 2 : DDict is just referenced, its lifetime must outlive its usage from DCtx. |
| */ |
| ZSTDLIB_API size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); |
| |
| /*! ZSTD_DCtx_refPrefix() : |
| * Reference a prefix (single-usage dictionary) to decompress next frame. |
| * This is the reverse operation of ZSTD_CCtx_refPrefix(), |
| * and must use the same prefix as the one used during compression. |
| * Prefix is **only used once**. Reference is discarded at end of frame. |
| * End of frame is reached when ZSTD_decompressStream() returns 0. |
| * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
| * Note 1 : Adding any prefix (including NULL) invalidates any previously set prefix or dictionary |
| * Note 2 : Prefix buffer is referenced. It **must** outlive decompression. |
| * Prefix buffer must remain unmodified up to the end of frame, |
| * reached when ZSTD_decompressStream() returns 0. |
| * Note 3 : By default, the prefix is treated as raw content (ZSTD_dct_rawContent). |
| * Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode (Experimental section) |
| * Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost. |
| * A full dictionary is more costly, as it requires building tables. |
| */ |
| ZSTDLIB_API size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, |
| const void* prefix, size_t prefixSize); |
| |
| /* === Memory management === */ |
| |
| /*! ZSTD_sizeof_*() : |
| * These functions give the _current_ memory usage of selected object. |
| * Note that object memory usage can evolve (increase or decrease) over time. */ |
| ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx); |
| ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx); |
| ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs); |
| ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds); |
| ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict); |
| ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict); |
| |
| #endif /* ZSTD_H_235446 */ |
| |
| |
| /* ************************************************************************************** |
| * ADVANCED AND EXPERIMENTAL FUNCTIONS |
| **************************************************************************************** |
| * The definitions in the following section are considered experimental. |
| * They are provided for advanced scenarios. |
| * They should never be used with a dynamic library, as prototypes may change in the future. |
| * Use them only in association with static linking. |
| * ***************************************************************************************/ |
| |
| #if !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY) |
| #define ZSTD_H_ZSTD_STATIC_LINKING_ONLY |
| |
| /* ************************************************************************************** |
| * experimental API (static linking only) |
| **************************************************************************************** |
| * The following symbols and constants |
| * are not planned to join "stable API" status in the near future. |
| * They can still change in future versions. |
| * Some of them are planned to remain in the static_only section indefinitely. |
| * Some of them might be removed in the future (especially when redundant with existing stable functions) |
| * ***************************************************************************************/ |
| |
| #define ZSTD_FRAMEHEADERSIZE_PREFIX(format) ((format) == ZSTD_f_zstd1 ? 5 : 1) /* minimum input size required to query frame header size */ |
| #define ZSTD_FRAMEHEADERSIZE_MIN(format) ((format) == ZSTD_f_zstd1 ? 6 : 2) |
| #define ZSTD_FRAMEHEADERSIZE_MAX 18 /* can be useful for static allocation */ |
| #define ZSTD_SKIPPABLEHEADERSIZE 8 |
| |
| /* compression parameter bounds */ |
| #define ZSTD_WINDOWLOG_MAX_32 30 |
| #define ZSTD_WINDOWLOG_MAX_64 31 |
| #define ZSTD_WINDOWLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64)) |
| #define ZSTD_WINDOWLOG_MIN 10 |
| #define ZSTD_HASHLOG_MAX ((ZSTD_WINDOWLOG_MAX < 30) ? ZSTD_WINDOWLOG_MAX : 30) |
| #define ZSTD_HASHLOG_MIN 6 |
| #define ZSTD_CHAINLOG_MAX_32 29 |
| #define ZSTD_CHAINLOG_MAX_64 30 |
| #define ZSTD_CHAINLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_CHAINLOG_MAX_32 : ZSTD_CHAINLOG_MAX_64)) |
| #define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN |
| #define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1) |
| #define ZSTD_SEARCHLOG_MIN 1 |
| #define ZSTD_MINMATCH_MAX 7 /* only for ZSTD_fast, other strategies are limited to 6 */ |
| #define ZSTD_MINMATCH_MIN 3 /* only for ZSTD_btopt+, faster strategies are limited to 4 */ |
| #define ZSTD_TARGETLENGTH_MAX ZSTD_BLOCKSIZE_MAX |
| #define ZSTD_TARGETLENGTH_MIN 0 /* note : comparing this constant to an unsigned results in a tautological test */ |
| #define ZSTD_STRATEGY_MIN ZSTD_fast |
| #define ZSTD_STRATEGY_MAX ZSTD_btultra2 |
| |
| |
| #define ZSTD_OVERLAPLOG_MIN 0 |
| #define ZSTD_OVERLAPLOG_MAX 9 |
| |
| #define ZSTD_WINDOWLOG_LIMIT_DEFAULT 27 /* by default, the streaming decoder will refuse any frame |
| * requiring larger than (1<<ZSTD_WINDOWLOG_LIMIT_DEFAULT) window size, |
| * to preserve host's memory from unreasonable requirements. |
| * This limit can be overridden using ZSTD_DCtx_setParameter(,ZSTD_d_windowLogMax,). |
| * The limit does not apply for one-pass decoders (such as ZSTD_decompress()), since no additional memory is allocated */ |
| |
| |
| /* LDM parameter bounds */ |
| #define ZSTD_LDM_HASHLOG_MIN ZSTD_HASHLOG_MIN |
| #define ZSTD_LDM_HASHLOG_MAX ZSTD_HASHLOG_MAX |
| #define ZSTD_LDM_MINMATCH_MIN 4 |
| #define ZSTD_LDM_MINMATCH_MAX 4096 |
| #define ZSTD_LDM_BUCKETSIZELOG_MIN 1 |
| #define ZSTD_LDM_BUCKETSIZELOG_MAX 8 |
| #define ZSTD_LDM_HASHRATELOG_MIN 0 |
| #define ZSTD_LDM_HASHRATELOG_MAX (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN) |
| |
| /* Advanced parameter bounds */ |
| #define ZSTD_TARGETCBLOCKSIZE_MIN 64 |
| #define ZSTD_TARGETCBLOCKSIZE_MAX ZSTD_BLOCKSIZE_MAX |
| #define ZSTD_SRCSIZEHINT_MIN 0 |
| #define ZSTD_SRCSIZEHINT_MAX INT_MAX |
| |
| /* internal */ |
| #define ZSTD_HASHLOG3_MAX 17 |
| |
| |
| /* --- Advanced types --- */ |
| |
| typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params; |
| |
| typedef struct { |
| unsigned int offset; /* The offset of the match. (NOT the same as the offset code) |
| * If offset == 0 and matchLength == 0, this sequence represents the last |
| * literals in the block of litLength size. |
| */ |
| |
| unsigned int litLength; /* Literal length of the sequence. */ |
| unsigned int matchLength; /* Match length of the sequence. */ |
| |
| /* Note: Users of this API may provide a sequence with matchLength == litLength == offset == 0. |
| * In this case, we will treat the sequence as a marker for a block boundary. |
| */ |
| |
| unsigned int rep; /* Represents which repeat offset is represented by the field 'offset'. |
| * Ranges from [0, 3]. |
| * |
| * Repeat offsets are essentially previous offsets from previous sequences sorted in |
| * recency order. For more detail, see doc/zstd_compression_format.md |
| * |
| * If rep == 0, then 'offset' does not contain a repeat offset. |
| * If rep > 0: |
| * If litLength != 0: |
| * rep == 1 --> offset == repeat_offset_1 |
| * rep == 2 --> offset == repeat_offset_2 |
| * rep == 3 --> offset == repeat_offset_3 |
| * If litLength == 0: |
| * rep == 1 --> offset == repeat_offset_2 |
| * rep == 2 --> offset == repeat_offset_3 |
| * rep == 3 --> offset == repeat_offset_1 - 1 |
| * |
| * Note: This field is optional. ZSTD_generateSequences() will calculate the value of |
| * 'rep', but repeat offsets do not necessarily need to be calculated from an external |
| * sequence provider's perspective. For example, ZSTD_compressSequences() does not |
| * use this 'rep' field at all (as of now). |
| */ |
| } ZSTD_Sequence; |
| |
| typedef struct { |
| unsigned windowLog; /*< largest match distance : larger == more compression, more memory needed during decompression */ |
| unsigned chainLog; /*< fully searched segment : larger == more compression, slower, more memory (useless for fast) */ |
| unsigned hashLog; /*< dispatch table : larger == faster, more memory */ |
| unsigned searchLog; /*< nb of searches : larger == more compression, slower */ |
| unsigned minMatch; /*< match length searched : larger == faster decompression, sometimes less compression */ |
| unsigned targetLength; /*< acceptable match size for optimal parser (only) : larger == more compression, slower */ |
| ZSTD_strategy strategy; /*< see ZSTD_strategy definition above */ |
| } ZSTD_compressionParameters; |
| |
| typedef struct { |
| int contentSizeFlag; /*< 1: content size will be in frame header (when known) */ |
| int checksumFlag; /*< 1: generate a 32-bits checksum using XXH64 algorithm at end of frame, for error detection */ |
| int noDictIDFlag; /*< 1: no dictID will be saved into frame header (dictID is only useful for dictionary compression) */ |
| } ZSTD_frameParameters; |
| |
| typedef struct { |
| ZSTD_compressionParameters cParams; |
| ZSTD_frameParameters fParams; |
| } ZSTD_parameters; |
| |
| typedef enum { |
| ZSTD_dct_auto = 0, /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */ |
| ZSTD_dct_rawContent = 1, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */ |
| ZSTD_dct_fullDict = 2 /* refuses to load a dictionary if it does not respect Zstandard's specification, starting with ZSTD_MAGIC_DICTIONARY */ |
| } ZSTD_dictContentType_e; |
| |
| typedef enum { |
| ZSTD_dlm_byCopy = 0, /*< Copy dictionary content internally */ |
| ZSTD_dlm_byRef = 1 /*< Reference dictionary content -- the dictionary buffer must outlive its users. */ |
| } ZSTD_dictLoadMethod_e; |
| |
| typedef enum { |
| ZSTD_f_zstd1 = 0, /* zstd frame format, specified in zstd_compression_format.md (default) */ |
| ZSTD_f_zstd1_magicless = 1 /* Variant of zstd frame format, without initial 4-bytes magic number. |
| * Useful to save 4 bytes per generated frame. |
| * Decoder cannot recognise automatically this format, requiring this instruction. */ |
| } ZSTD_format_e; |
| |
| typedef enum { |
| /* Note: this enum controls ZSTD_d_forceIgnoreChecksum */ |
| ZSTD_d_validateChecksum = 0, |
| ZSTD_d_ignoreChecksum = 1 |
| } ZSTD_forceIgnoreChecksum_e; |
| |
| typedef enum { |
| /* Note: this enum controls ZSTD_d_refMultipleDDicts */ |
| ZSTD_rmd_refSingleDDict = 0, |
| ZSTD_rmd_refMultipleDDicts = 1 |
| } ZSTD_refMultipleDDicts_e; |
| |
| typedef enum { |
| /* Note: this enum and the behavior it controls are effectively internal |
| * implementation details of the compressor. They are expected to continue |
| * to evolve and should be considered only in the context of extremely |
| * advanced performance tuning. |
| * |
| * Zstd currently supports the use of a CDict in three ways: |
| * |
| * - The contents of the CDict can be copied into the working context. This |
| * means that the compression can search both the dictionary and input |
| * while operating on a single set of internal tables. This makes |
| * the compression faster per-byte of input. However, the initial copy of |
| * the CDict's tables incurs a fixed cost at the beginning of the |
| * compression. For small compressions (< 8 KB), that copy can dominate |
| * the cost of the compression. |
| * |
| * - The CDict's tables can be used in-place. In this model, compression is |
| * slower per input byte, because the compressor has to search two sets of |
| * tables. However, this model incurs no start-up cost (as long as the |
| * working context's tables can be reused). For small inputs, this can be |
| * faster than copying the CDict's tables. |
| * |
| * - The CDict's tables are not used at all, and instead we use the working |
| * context alone to reload the dictionary and use params based on the source |
| * size. See ZSTD_compress_insertDictionary() and ZSTD_compress_usingDict(). |
| * This method is effective when the dictionary sizes are very small relative |
| * to the input size, and the input size is fairly large to begin with. |
| * |
| * Zstd has a simple internal heuristic that selects which strategy to use |
| * at the beginning of a compression. However, if experimentation shows that |
| * Zstd is making poor choices, it is possible to override that choice with |
| * this enum. |
| */ |
| ZSTD_dictDefaultAttach = 0, /* Use the default heuristic. */ |
| ZSTD_dictForceAttach = 1, /* Never copy the dictionary. */ |
| ZSTD_dictForceCopy = 2, /* Always copy the dictionary. */ |
| ZSTD_dictForceLoad = 3 /* Always reload the dictionary */ |
| } ZSTD_dictAttachPref_e; |
| |
| typedef enum { |
| ZSTD_lcm_auto = 0, /*< Automatically determine the compression mode based on the compression level. |
| * Negative compression levels will be uncompressed, and positive compression |
| * levels will be compressed. */ |
| ZSTD_lcm_huffman = 1, /*< Always attempt Huffman compression. Uncompressed literals will still be |
| * emitted if Huffman compression is not profitable. */ |
| ZSTD_lcm_uncompressed = 2 /*< Always emit uncompressed literals. */ |
| } ZSTD_literalCompressionMode_e; |
| |
| |
| /* ************************************* |
| * Frame size functions |
| ***************************************/ |
| |
| /*! ZSTD_findDecompressedSize() : |
| * `src` should point to the start of a series of ZSTD encoded and/or skippable frames |
| * `srcSize` must be the _exact_ size of this series |
| * (i.e. there should be a frame boundary at `src + srcSize`) |
| * @return : - decompressed size of all data in all successive frames |
| * - if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN |
| * - if an error occurred: ZSTD_CONTENTSIZE_ERROR |
| * |
| * note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode. |
| * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. |
| * In which case, it's necessary to use streaming mode to decompress data. |
| * note 2 : decompressed size is always present when compression is done with ZSTD_compress() |
| * note 3 : decompressed size can be very large (64-bits value), |
| * potentially larger than what local system can handle as a single memory segment. |
| * In which case, it's necessary to use streaming mode to decompress data. |
| * note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified. |
| * Always ensure result fits within application's authorized limits. |
| * Each application can set its own limits. |
| * note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to |
| * read each contained frame header. This is fast as most of the data is skipped, |
| * however it does mean that all frame data must be present and valid. */ |
| ZSTDLIB_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize); |
| |
| /*! ZSTD_decompressBound() : |
| * `src` should point to the start of a series of ZSTD encoded and/or skippable frames |
| * `srcSize` must be the _exact_ size of this series |
| * (i.e. there should be a frame boundary at `src + srcSize`) |
| * @return : - upper-bound for the decompressed size of all data in all successive frames |
| * - if an error occurred: ZSTD_CONTENTSIZE_ERROR |
| * |
| * note 1 : an error can occur if `src` contains an invalid or incorrectly formatted frame. |
| * note 2 : the upper-bound is exact when the decompressed size field is available in every ZSTD encoded frame of `src`. |
| * in this case, `ZSTD_findDecompressedSize` and `ZSTD_decompressBound` return the same value. |
| * note 3 : when the decompressed size field isn't available, the upper-bound for that frame is calculated by: |
| * upper-bound = # blocks * min(128 KB, Window_Size) |
| */ |
| ZSTDLIB_API unsigned long long ZSTD_decompressBound(const void* src, size_t srcSize); |
| |
| /*! ZSTD_frameHeaderSize() : |
| * srcSize must be >= ZSTD_FRAMEHEADERSIZE_PREFIX. |
| * @return : size of the Frame Header, |
| * or an error code (if srcSize is too small) */ |
| ZSTDLIB_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize); |
| |
| typedef enum { |
| ZSTD_sf_noBlockDelimiters = 0, /* Representation of ZSTD_Sequence has no block delimiters, sequences only */ |
| ZSTD_sf_explicitBlockDelimiters = 1 /* Representation of ZSTD_Sequence contains explicit block delimiters */ |
| } ZSTD_sequenceFormat_e; |
| |
| /*! ZSTD_generateSequences() : |
| * Generate sequences using ZSTD_compress2, given a source buffer. |
| * |
| * Each block will end with a dummy sequence |
| * with offset == 0, matchLength == 0, and litLength == length of last literals. |
| * litLength may be == 0, and if so, then the sequence of (of: 0 ml: 0 ll: 0) |
| * simply acts as a block delimiter. |
| * |
| * zc can be used to insert custom compression params. |
| * This function invokes ZSTD_compress2 |
| * |
| * The output of this function can be fed into ZSTD_compressSequences() with CCtx |
| * setting of ZSTD_c_blockDelimiters as ZSTD_sf_explicitBlockDelimiters |
| * @return : number of sequences generated |
| */ |
| |
| ZSTDLIB_API size_t ZSTD_generateSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs, |
| size_t outSeqsSize, const void* src, size_t srcSize); |
| |
| /*! ZSTD_mergeBlockDelimiters() : |
| * Given an array of ZSTD_Sequence, remove all sequences that represent block delimiters/last literals |
| * by merging them into into the literals of the next sequence. |
| * |
| * As such, the final generated result has no explicit representation of block boundaries, |
| * and the final last literals segment is not represented in the sequences. |
| * |
| * The output of this function can be fed into ZSTD_compressSequences() with CCtx |
| * setting of ZSTD_c_blockDelimiters as ZSTD_sf_noBlockDelimiters |
| * @return : number of sequences left after merging |
| */ |
| ZSTDLIB_API size_t ZSTD_mergeBlockDelimiters(ZSTD_Sequence* sequences, size_t seqsSize); |
| |
| /*! ZSTD_compressSequences() : |
| * Compress an array of ZSTD_Sequence, generated from the original source buffer, into dst. |
| * If a dictionary is included, then the cctx should reference the dict. (see: ZSTD_CCtx_refCDict(), ZSTD_CCtx_loadDictionary(), etc.) |
| * The entire source is compressed into a single frame. |
| * |
| * The compression behavior changes based on cctx params. In particular: |
| * If ZSTD_c_blockDelimiters == ZSTD_sf_noBlockDelimiters, the array of ZSTD_Sequence is expected to contain |
| * no block delimiters (defined in ZSTD_Sequence). Block boundaries are roughly determined based on |
| * the block size derived from the cctx, and sequences may be split. This is the default setting. |
| * |
| * If ZSTD_c_blockDelimiters == ZSTD_sf_explicitBlockDelimiters, the array of ZSTD_Sequence is expected to contain |
| * block delimiters (defined in ZSTD_Sequence). Behavior is undefined if no block delimiters are provided. |
| * |
| * If ZSTD_c_validateSequences == 0, this function will blindly accept the sequences provided. Invalid sequences cause undefined |
| * behavior. If ZSTD_c_validateSequences == 1, then if sequence is invalid (see doc/zstd_compression_format.md for |
| * specifics regarding offset/matchlength requirements) then the function will bail out and return an error. |
| * |
| * In addition to the two adjustable experimental params, there are other important cctx params. |
| * - ZSTD_c_minMatch MUST be set as less than or equal to the smallest match generated by the match finder. It has a minimum value of ZSTD_MINMATCH_MIN. |
| * - ZSTD_c_compressionLevel accordingly adjusts the strength of the entropy coder, as it would in typical compression. |
| * - ZSTD_c_windowLog affects offset validation: this function will return an error at higher debug levels if a provided offset |
| * is larger than what the spec allows for a given window log and dictionary (if present). See: doc/zstd_compression_format.md |
| * |
| * Note: Repcodes are, as of now, always re-calculated within this function, so ZSTD_Sequence::rep is unused. |
| * Note 2: Once we integrate ability to ingest repcodes, the explicit block delims mode must respect those repcodes exactly, |
| * and cannot emit an RLE block that disagrees with the repcode history |
| * @return : final compressed size or a ZSTD error. |
| */ |
| ZSTDLIB_API size_t ZSTD_compressSequences(ZSTD_CCtx* const cctx, void* dst, size_t dstSize, |
| const ZSTD_Sequence* inSeqs, size_t inSeqsSize, |
| const void* src, size_t srcSize); |
| |
| |
| /*! ZSTD_writeSkippableFrame() : |
| * Generates a zstd skippable frame containing data given by src, and writes it to dst buffer. |
| * |
| * Skippable frames begin with a a 4-byte magic number. There are 16 possible choices of magic number, |
| * ranging from ZSTD_MAGIC_SKIPPABLE_START to ZSTD_MAGIC_SKIPPABLE_START+15. |
| * As such, the parameter magicVariant controls the exact skippable frame magic number variant used, so |
| * the magic number used will be ZSTD_MAGIC_SKIPPABLE_START + magicVariant. |
| * |
| * Returns an error if destination buffer is not large enough, if the source size is not representable |
| * with a 4-byte unsigned int, or if the parameter magicVariant is greater than 15 (and therefore invalid). |
| * |
| * @return : number of bytes written or a ZSTD error. |
| */ |
| ZSTDLIB_API size_t ZSTD_writeSkippableFrame(void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, unsigned magicVariant); |
| |
| |
| /* ************************************* |
| * Memory management |
| ***************************************/ |
| |
| /*! ZSTD_estimate*() : |
| * These functions make it possible to estimate memory usage |
| * of a future {D,C}Ctx, before its creation. |
| * |
| * ZSTD_estimateCCtxSize() will provide a memory budget large enough |
| * for any compression level up to selected one. |
| * Note : Unlike ZSTD_estimateCStreamSize*(), this estimate |
| * does not include space for a window buffer. |
| * Therefore, the estimation is only guaranteed for single-shot compressions, not streaming. |
| * The estimate will assume the input may be arbitrarily large, |
| * which is the worst case. |
| * |
| * When srcSize can be bound by a known and rather "small" value, |
| * this fact can be used to provide a tighter estimation |
| * because the CCtx compression context will need less memory. |
| * This tighter estimation can be provided by more advanced functions |
| * ZSTD_estimateCCtxSize_usingCParams(), which can be used in tandem with ZSTD_getCParams(), |
| * and ZSTD_estimateCCtxSize_usingCCtxParams(), which can be used in tandem with ZSTD_CCtxParams_setParameter(). |
| * Both can be used to estimate memory using custom compression parameters and arbitrary srcSize limits. |
| * |
| * Note 2 : only single-threaded compression is supported. |
| * ZSTD_estimateCCtxSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1. |
| */ |
| ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel); |
| ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams); |
| ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params); |
| ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void); |
| |
| /*! ZSTD_estimateCStreamSize() : |
| * ZSTD_estimateCStreamSize() will provide a budget large enough for any compression level up to selected one. |
| * It will also consider src size to be arbitrarily "large", which is worst case. |
| * If srcSize is known to always be small, ZSTD_estimateCStreamSize_usingCParams() can provide a tighter estimation. |
| * ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. |
| * ZSTD_estimateCStreamSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParams_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_c_nbWorkers is >= 1. |
| * Note : CStream size estimation is only correct for single-threaded compression. |
| * ZSTD_DStream memory budget depends on window Size. |
| * This information can be passed manually, using ZSTD_estimateDStreamSize, |
| * or deducted from a valid frame Header, using ZSTD_estimateDStreamSize_fromFrame(); |
| * Note : if streaming is init with function ZSTD_init?Stream_usingDict(), |
| * an internal ?Dict will be created, which additional size is not estimated here. |
| * In this case, get total size by adding ZSTD_estimate?DictSize */ |
| ZSTDLIB_API size_t ZSTD_estimateCStreamSize(int compressionLevel); |
| ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams); |
| ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params); |
| ZSTDLIB_API size_t ZSTD_estimateDStreamSize(size_t windowSize); |
| ZSTDLIB_API size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize); |
| |
| /*! ZSTD_estimate?DictSize() : |
| * ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict(). |
| * ZSTD_estimateCDictSize_advanced() makes it possible to control compression parameters precisely, like ZSTD_createCDict_advanced(). |
| * Note : dictionaries created by reference (`ZSTD_dlm_byRef`) are logically smaller. |
| */ |
| ZSTDLIB_API size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel); |
| ZSTDLIB_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod); |
| ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod); |
| |
| /*! ZSTD_initStatic*() : |
| * Initialize an object using a pre-allocated fixed-size buffer. |
| * workspace: The memory area to emplace the object into. |
| * Provided pointer *must be 8-bytes aligned*. |
| * Buffer must outlive object. |
| * workspaceSize: Use ZSTD_estimate*Size() to determine |
| * how large workspace must be to support target scenario. |
| * @return : pointer to object (same address as workspace, just different type), |
| * or NULL if error (size too small, incorrect alignment, etc.) |
| * Note : zstd will never resize nor malloc() when using a static buffer. |
| * If the object requires more memory than available, |
| * zstd will just error out (typically ZSTD_error_memory_allocation). |
| * Note 2 : there is no corresponding "free" function. |
| * Since workspace is allocated externally, it must be freed externally too. |
| * Note 3 : cParams : use ZSTD_getCParams() to convert a compression level |
| * into its associated cParams. |
| * Limitation 1 : currently not compatible with internal dictionary creation, triggered by |
| * ZSTD_CCtx_loadDictionary(), ZSTD_initCStream_usingDict() or ZSTD_initDStream_usingDict(). |
| * Limitation 2 : static cctx currently not compatible with multi-threading. |
| * Limitation 3 : static dctx is incompatible with legacy support. |
| */ |
| ZSTDLIB_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize); |
| ZSTDLIB_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /*< same as ZSTD_initStaticCCtx() */ |
| |
| ZSTDLIB_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize); |
| ZSTDLIB_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /*< same as ZSTD_initStaticDCtx() */ |
| |
| ZSTDLIB_API const ZSTD_CDict* ZSTD_initStaticCDict( |
| void* workspace, size_t workspaceSize, |
| const void* dict, size_t dictSize, |
| ZSTD_dictLoadMethod_e dictLoadMethod, |
| ZSTD_dictContentType_e dictContentType, |
| ZSTD_compressionParameters cParams); |
| |
| ZSTDLIB_API const ZSTD_DDict* ZSTD_initStaticDDict( |
| void* workspace, size_t workspaceSize, |
| const void* dict, size_t dictSize, |
| ZSTD_dictLoadMethod_e dictLoadMethod, |
| ZSTD_dictContentType_e dictContentType); |
| |
| |
| /*! Custom memory allocation : |
| * These prototypes make it possible to pass your own allocation/free functions. |
| * ZSTD_customMem is provided at creation time, using ZSTD_create*_advanced() variants listed below. |
| * All allocation/free operations will be completed using these custom variants instead of regular <stdlib.h> ones. |
| */ |
| typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size); |
| typedef void (*ZSTD_freeFunction) (void* opaque, void* address); |
| typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem; |
| static |
| __attribute__((__unused__)) |
| ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; /*< this constant defers to stdlib's functions */ |
| |
| ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem); |
| ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem); |
| ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem); |
| ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem); |
| |
| ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize, |
| ZSTD_dictLoadMethod_e dictLoadMethod, |
| ZSTD_dictContentType_e dictContentType, |
| ZSTD_compressionParameters cParams, |
| ZSTD_customMem customMem); |
| |
| /* ! Thread pool : |
| * These prototypes make it possible to share a thread pool among multiple compression contexts. |
| * This can limit resources for applications with multiple threads where each one uses |
| * a threaded compression mode (via ZSTD_c_nbWorkers parameter). |
| * ZSTD_createThreadPool creates a new thread pool with a given number of threads. |
| * Note that the lifetime of such pool must exist while being used. |
| * ZSTD_CCtx_refThreadPool assigns a thread pool to a context (use NULL argument value |
| * to use an internal thread pool). |
| * ZSTD_freeThreadPool frees a thread pool, accepts NULL pointer. |
| */ |
| typedef struct POOL_ctx_s ZSTD_threadPool; |
| ZSTDLIB_API ZSTD_threadPool* ZSTD_createThreadPool(size_t numThreads); |
| ZSTDLIB_API void ZSTD_freeThreadPool (ZSTD_threadPool* pool); /* accept NULL pointer */ |
| ZSTDLIB_API size_t ZSTD_CCtx_refThreadPool(ZSTD_CCtx* cctx, ZSTD_threadPool* pool); |
| |
| |
| /* |
| * This API is temporary and is expected to change or disappear in the future! |
| */ |
| ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced2( |
| const void* dict, size_t dictSize, |
| ZSTD_dictLoadMethod_e dictLoadMethod, |
| ZSTD_dictContentType_e dictContentType, |
| const ZSTD_CCtx_params* cctxParams, |
| ZSTD_customMem customMem); |
| |
| ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced( |
| const void* dict, size_t dictSize, |
| ZSTD_dictLoadMethod_e dictLoadMethod, |
| ZSTD_dictContentType_e dictContentType, |
| ZSTD_customMem customMem); |
| |
| |
| /* ************************************* |
| * Advanced compression functions |
| ***************************************/ |
| |
| /*! ZSTD_createCDict_byReference() : |
| * Create a digested dictionary for compression |
| * Dictionary content is just referenced, not duplicated. |
| * As a consequence, `dictBuffer` **must** outlive CDict, |
| * and its content must remain unmodified throughout the lifetime of CDict. |
| * note: equivalent to ZSTD_createCDict_advanced(), with dictLoadMethod==ZSTD_dlm_byRef */ |
| ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel); |
| |
| /*! ZSTD_getDictID_fromCDict() : |
| * Provides the dictID of the dictionary loaded into `cdict`. |
| * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty. |
| * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */ |
| ZSTDLIB_API unsigned ZSTD_getDictID_fromCDict(const ZSTD_CDict* cdict); |
| |
| /*! ZSTD_getCParams() : |
| * @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize. |
| * `estimatedSrcSize` value is optional, select 0 if not known */ |
| ZSTDLIB_API ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); |
| |
| /*! ZSTD_getParams() : |
| * same as ZSTD_getCParams(), but @return a full `ZSTD_parameters` object instead of sub-component `ZSTD_compressionParameters`. |
| * All fields of `ZSTD_frameParameters` are set to default : contentSize=1, checksum=0, noDictID=0 */ |
| ZSTDLIB_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); |
| |
| /*! ZSTD_checkCParams() : |
| * Ensure param values remain within authorized range. |
| * @return 0 on success, or an error code (can be checked with ZSTD_isError()) */ |
| ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params); |
| |
| /*! ZSTD_adjustCParams() : |
| * optimize params for a given `srcSize` and `dictSize`. |
| * `srcSize` can be unknown, in which case use ZSTD_CONTENTSIZE_UNKNOWN. |
| * `dictSize` must be `0` when there is no dictionary. |
| * cPar can be invalid : all parameters will be clamped within valid range in the @return struct. |
| * This function never fails (wide contract) */ |
| ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize); |
| |
| /*! ZSTD_compress_advanced() : |
| * Note : this function is now DEPRECATED. |
| * It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_setParameter() and other parameter setters. |
| * This prototype will be marked as deprecated and generate compilation warning on reaching v1.5.x */ |
| ZSTDLIB_API size_t ZSTD_compress_advanced(ZSTD_CCtx* cctx, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, |
| const void* dict,size_t dictSize, |
| ZSTD_parameters params); |
| |
| /*! ZSTD_compress_usingCDict_advanced() : |
| * Note : this function is now REDUNDANT. |
| * It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_loadDictionary() and other parameter setters. |
| * This prototype will be marked as deprecated and generate compilation warning in some future version */ |
| ZSTDLIB_API size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, |
| const ZSTD_CDict* cdict, |
| ZSTD_frameParameters fParams); |
| |
| |
| /*! ZSTD_CCtx_loadDictionary_byReference() : |
| * Same as ZSTD_CCtx_loadDictionary(), but dictionary content is referenced, instead of being copied into CCtx. |
| * It saves some memory, but also requires that `dict` outlives its usage within `cctx` */ |
| ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); |
| |
| /*! ZSTD_CCtx_loadDictionary_advanced() : |
| * Same as ZSTD_CCtx_loadDictionary(), but gives finer control over |
| * how to load the dictionary (by copy ? by reference ?) |
| * and how to interpret it (automatic ? force raw mode ? full mode only ?) */ |
| ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType); |
| |
| /*! ZSTD_CCtx_refPrefix_advanced() : |
| * Same as ZSTD_CCtx_refPrefix(), but gives finer control over |
| * how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */ |
| ZSTDLIB_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType); |
| |
| /* === experimental parameters === */ |
| /* these parameters can be used with ZSTD_setParameter() |
| * they are not guaranteed to remain supported in the future */ |
| |
| /* Enables rsyncable mode, |
| * which makes compressed files more rsync friendly |
| * by adding periodic synchronization points to the compressed data. |
| * The target average block size is ZSTD_c_jobSize / 2. |
| * It's possible to modify the job size to increase or decrease |
| * the granularity of the synchronization point. |
| * Once the jobSize is smaller than the window size, |
| * it will result in compression ratio degradation. |
| * NOTE 1: rsyncable mode only works when multithreading is enabled. |
| * NOTE 2: rsyncable performs poorly in combination with long range mode, |
| * since it will decrease the effectiveness of synchronization points, |
| * though mileage may vary. |
| * NOTE 3: Rsyncable mode limits maximum compression speed to ~400 MB/s. |
| * If the selected compression level is already running significantly slower, |
| * the overall speed won't be significantly impacted. |
| */ |
| #define ZSTD_c_rsyncable ZSTD_c_experimentalParam1 |
| |
| /* Select a compression format. |
| * The value must be of type ZSTD_format_e. |
| * See ZSTD_format_e enum definition for details */ |
| #define ZSTD_c_format ZSTD_c_experimentalParam2 |
| |
| /* Force back-reference distances to remain < windowSize, |
| * even when referencing into Dictionary content (default:0) */ |
| #define ZSTD_c_forceMaxWindow ZSTD_c_experimentalParam3 |
| |
| /* Controls whether the contents of a CDict |
| * are used in place, or copied into the working context. |
| * Accepts values from the ZSTD_dictAttachPref_e enum. |
| * See the comments on that enum for an explanation of the feature. */ |
| #define ZSTD_c_forceAttachDict ZSTD_c_experimentalParam4 |
| |
| /* Controls how the literals are compressed (default is auto). |
| * The value must be of type ZSTD_literalCompressionMode_e. |
| * See ZSTD_literalCompressionMode_t enum definition for details. |
| */ |
| #define ZSTD_c_literalCompressionMode ZSTD_c_experimentalParam5 |
| |
| /* Tries to fit compressed block size to be around targetCBlockSize. |
| * No target when targetCBlockSize == 0. |
| * There is no guarantee on compressed block size (default:0) */ |
| #define ZSTD_c_targetCBlockSize ZSTD_c_experimentalParam6 |
| |
| /* User's best guess of source size. |
| * Hint is not valid when srcSizeHint == 0. |
| * There is no guarantee that hint is close to actual source size, |
| * but compression ratio may regress significantly if guess considerably underestimates */ |
| #define ZSTD_c_srcSizeHint ZSTD_c_experimentalParam7 |
| |
| /* Controls whether the new and experimental "dedicated dictionary search |
| * structure" can be used. This feature is still rough around the edges, be |
| * prepared for surprising behavior! |
| * |
| * How to use it: |
| * |
| * When using a CDict, whether to use this feature or not is controlled at |
| * CDict creation, and it must be set in a CCtxParams set passed into that |
| * construction (via ZSTD_createCDict_advanced2()). A compression will then |
| * use the feature or not based on how the CDict was constructed; the value of |
| * this param, set in the CCtx, will have no effect. |
| * |
| * However, when a dictionary buffer is passed into a CCtx, such as via |
| * ZSTD_CCtx_loadDictionary(), this param can be set on the CCtx to control |
| * whether the CDict that is created internally can use the feature or not. |
| * |
| * What it does: |
| * |
| * Normally, the internal data structures of the CDict are analogous to what |
| * would be stored in a CCtx after compressing the contents of a dictionary. |
| * To an approximation, a compression using a dictionary can then use those |
| * data structures to simply continue what is effectively a streaming |
| * compression where the simulated compression of the dictionary left off. |
| * Which is to say, the search structures in the CDict are normally the same |
| * format as in the CCtx. |
| * |
| * It is possible to do better, since the CDict is not like a CCtx: the search |
| * structures are written once during CDict creation, and then are only read |
| * after that, while the search structures in the CCtx are both read and |
| * written as the compression goes along. This means we can choose a search |
| * structure for the dictionary that is read-optimized. |
| * |
| * This feature enables the use of that different structure. |
| * |
| * Note that some of the members of the ZSTD_compressionParameters struct have |
| * different semantics and constraints in the dedicated search structure. It is |
| * highly recommended that you simply set a compression level in the CCtxParams |
| * you pass into the CDict creation call, and avoid messing with the cParams |
| * directly. |
| * |
| * Effects: |
| * |
| * This will only have any effect when the selected ZSTD_strategy |
| * implementation supports this feature. Currently, that's limited to |
| * ZSTD_greedy, ZSTD_lazy, and ZSTD_lazy2. |
| * |
| * Note that this means that the CDict tables can no longer be copied into the |
| * CCtx, so the dict attachment mode ZSTD_dictForceCopy will no longer be |
| * useable. The dictionary can only be attached or reloaded. |
| * |
| * In general, you should expect compression to be faster--sometimes very much |
| * so--and CDict creation to be slightly slower. Eventually, we will probably |
| * make this mode the default. |
| */ |
| #define ZSTD_c_enableDedicatedDictSearch ZSTD_c_experimentalParam8 |
| |
| /* ZSTD_c_stableInBuffer |
| * Experimental parameter. |
| * Default is 0 == disabled. Set to 1 to enable. |
| * |
| * Tells the compressor that the ZSTD_inBuffer will ALWAYS be the same |
| * between calls, except for the modifications that zstd makes to pos (the |
| * caller must not modify pos). This is checked by the compressor, and |
| * compression will fail if it ever changes. This means the only flush |
| * mode that makes sense is ZSTD_e_end, so zstd will error if ZSTD_e_end |
| * is not used. The data in the ZSTD_inBuffer in the range [src, src + pos) |
| * MUST not be modified during compression or you will get data corruption. |
| * |
| * When this flag is enabled zstd won't allocate an input window buffer, |
| * because the user guarantees it can reference the ZSTD_inBuffer until |
| * the frame is complete. But, it will still allocate an output buffer |
| * large enough to fit a block (see ZSTD_c_stableOutBuffer). This will also |
| * avoid the memcpy() from the input buffer to the input window buffer. |
| * |
| * NOTE: ZSTD_compressStream2() will error if ZSTD_e_end is not used. |
| * That means this flag cannot be used with ZSTD_compressStream(). |
| * |
| * NOTE: So long as the ZSTD_inBuffer always points to valid memory, using |
| * this flag is ALWAYS memory safe, and will never access out-of-bounds |
| * memory. However, compression WILL fail if you violate the preconditions. |
| * |
| * WARNING: The data in the ZSTD_inBuffer in the range [dst, dst + pos) MUST |
| * not be modified during compression or you will get data corruption. This |
| * is because zstd needs to reference data in the ZSTD_inBuffer to find |
| * matches. Normally zstd maintains its own window buffer for this purpose, |
| * but passing this flag tells zstd to use the user provided buffer. |
| */ |
| #define ZSTD_c_stableInBuffer ZSTD_c_experimentalParam9 |
| |
| /* ZSTD_c_stableOutBuffer |
| * Experimental parameter. |
| * Default is 0 == disabled. Set to 1 to enable. |
| * |
| * Tells he compressor that the ZSTD_outBuffer will not be resized between |
| * calls. Specifically: (out.size - out.pos) will never grow. This gives the |
| * compressor the freedom to say: If the compressed data doesn't fit in the |
| * output buffer then return ZSTD_error_dstSizeTooSmall. This allows us to |
| * always decompress directly into the output buffer, instead of decompressing |
| * into an internal buffer and copying to the output buffer. |
| * |
| * When this flag is enabled zstd won't allocate an output buffer, because |
| * it can write directly to the ZSTD_outBuffer. It will still allocate the |
| * input window buffer (see ZSTD_c_stableInBuffer). |
| * |
| * Zstd will check that (out.size - out.pos) never grows and return an error |
| * if it does. While not strictly necessary, this should prevent surprises. |
| */ |
| #define ZSTD_c_stableOutBuffer ZSTD_c_experimentalParam10 |
| |
| /* ZSTD_c_blockDelimiters |
| * Default is 0 == ZSTD_sf_noBlockDelimiters. |
| * |
| * For use with sequence compression API: ZSTD_compressSequences(). |
| * |
| * Designates whether or not the given array of ZSTD_Sequence contains block delimiters |
| * and last literals, which are defined as sequences with offset == 0 and matchLength == 0. |
| * See the definition of ZSTD_Sequence for more specifics. |
| */ |
| #define ZSTD_c_blockDelimiters ZSTD_c_experimentalParam11 |
| |
| /* ZSTD_c_validateSequences |
| * Default is 0 == disabled. Set to 1 to enable sequence validation. |
| * |
| * For use with sequence compression API: ZSTD_compressSequences(). |
| * Designates whether or not we validate sequences provided to ZSTD_compressSequences() |
| * during function execution. |
| * |
| * Without validation, providing a sequence that does not conform to the zstd spec will cause |
| * undefined behavior, and may produce a corrupted block. |
| * |
| * With validation enabled, a if sequence is invalid (see doc/zstd_compression_format.md for |
| * specifics regarding offset/matchlength requirements) then the function will bail out and |
| * return an error. |
| * |
| */ |
| #define ZSTD_c_validateSequences ZSTD_c_experimentalParam12 |
| |
| /*! ZSTD_CCtx_getParameter() : |
| * Get the requested compression parameter value, selected by enum ZSTD_cParameter, |
| * and store it into int* value. |
| * @return : 0, or an error code (which can be tested with ZSTD_isError()). |
| */ |
| ZSTDLIB_API size_t ZSTD_CCtx_getParameter(const ZSTD_CCtx* cctx, ZSTD_cParameter param, int* value); |
| |
| |
| /*! ZSTD_CCtx_params : |
| * Quick howto : |
| * - ZSTD_createCCtxParams() : Create a ZSTD_CCtx_params structure |
| * - ZSTD_CCtxParams_setParameter() : Push parameters one by one into |
| * an existing ZSTD_CCtx_params structure. |
| * This is similar to |
| * ZSTD_CCtx_setParameter(). |
| * - ZSTD_CCtx_setParametersUsingCCtxParams() : Apply parameters to |
| * an existing CCtx. |
| * These parameters will be applied to |
| * all subsequent frames. |
| * - ZSTD_compressStream2() : Do compression using the CCtx. |
| * - ZSTD_freeCCtxParams() : Free the memory, accept NULL pointer. |
| * |
| * This can be used with ZSTD_estimateCCtxSize_advanced_usingCCtxParams() |
| * for static allocation of CCtx for single-threaded compression. |
| */ |
| ZSTDLIB_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void); |
| ZSTDLIB_API size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params); /* accept NULL pointer */ |
| |
| /*! ZSTD_CCtxParams_reset() : |
| * Reset params to default values. |
| */ |
| ZSTDLIB_API size_t ZSTD_CCtxParams_reset(ZSTD_CCtx_params* params); |
| |
| /*! ZSTD_CCtxParams_init() : |
| * Initializes the compression parameters of cctxParams according to |
| * compression level. All other parameters are reset to their default values. |
| */ |
| ZSTDLIB_API size_t ZSTD_CCtxParams_init(ZSTD_CCtx_params* cctxParams, int compressionLevel); |
| |
| /*! ZSTD_CCtxParams_init_advanced() : |
| * Initializes the compression and frame parameters of cctxParams according to |
| * params. All other parameters are reset to their default values. |
| */ |
| ZSTDLIB_API size_t ZSTD_CCtxParams_init_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params); |
| |
| /*! ZSTD_CCtxParams_setParameter() : |
| * Similar to ZSTD_CCtx_setParameter. |
| * Set one compression parameter, selected by enum ZSTD_cParameter. |
| * Parameters must be applied to a ZSTD_CCtx using |
| * ZSTD_CCtx_setParametersUsingCCtxParams(). |
| * @result : a code representing success or failure (which can be tested with |
| * ZSTD_isError()). |
| */ |
| ZSTDLIB_API size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int value); |
| |
| /*! ZSTD_CCtxParams_getParameter() : |
| * Similar to ZSTD_CCtx_getParameter. |
| * Get the requested value of one compression parameter, selected by enum ZSTD_cParameter. |
| * @result : 0, or an error code (which can be tested with ZSTD_isError()). |
| */ |
| ZSTDLIB_API size_t ZSTD_CCtxParams_getParameter(const ZSTD_CCtx_params* params, ZSTD_cParameter param, int* value); |
| |
| /*! ZSTD_CCtx_setParametersUsingCCtxParams() : |
| * Apply a set of ZSTD_CCtx_params to the compression context. |
| * This can be done even after compression is started, |
| * if nbWorkers==0, this will have no impact until a new compression is started. |
| * if nbWorkers>=1, new parameters will be picked up at next job, |
| * with a few restrictions (windowLog, pledgedSrcSize, nbWorkers, jobSize, and overlapLog are not updated). |
| */ |
| ZSTDLIB_API size_t ZSTD_CCtx_setParametersUsingCCtxParams( |
| ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params); |
| |
| /*! ZSTD_compressStream2_simpleArgs() : |
| * Same as ZSTD_compressStream2(), |
| * but using only integral types as arguments. |
| * This variant might be helpful for binders from dynamic languages |
| * which have troubles handling structures containing memory pointers. |
| */ |
| ZSTDLIB_API size_t ZSTD_compressStream2_simpleArgs ( |
| ZSTD_CCtx* cctx, |
| void* dst, size_t dstCapacity, size_t* dstPos, |
| const void* src, size_t srcSize, size_t* srcPos, |
| ZSTD_EndDirective endOp); |
| |
| |
| /* ************************************* |
| * Advanced decompression functions |
| ***************************************/ |
| |
| /*! ZSTD_isFrame() : |
| * Tells if the content of `buffer` starts with a valid Frame Identifier. |
| * Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0. |
| * Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled. |
| * Note 3 : Skippable Frame Identifiers are considered valid. */ |
| ZSTDLIB_API unsigned ZSTD_isFrame(const void* buffer, size_t size); |
| |
| /*! ZSTD_createDDict_byReference() : |
| * Create a digested dictionary, ready to start decompression operation without startup delay. |
| * Dictionary content is referenced, and therefore stays in dictBuffer. |
| * It is important that dictBuffer outlives DDict, |
| * it must remain read accessible throughout the lifetime of DDict */ |
| ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize); |
| |
| /*! ZSTD_DCtx_loadDictionary_byReference() : |
| * Same as ZSTD_DCtx_loadDictionary(), |
| * but references `dict` content instead of copying it into `dctx`. |
| * This saves memory if `dict` remains around., |
| * However, it's imperative that `dict` remains accessible (and unmodified) while being used, so it must outlive decompression. */ |
| ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); |
| |
| /*! ZSTD_DCtx_loadDictionary_advanced() : |
| * Same as ZSTD_DCtx_loadDictionary(), |
| * but gives direct control over |
| * how to load the dictionary (by copy ? by reference ?) |
| * and how to interpret it (automatic ? force raw mode ? full mode only ?). */ |
| ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType); |
| |
| /*! ZSTD_DCtx_refPrefix_advanced() : |
| * Same as ZSTD_DCtx_refPrefix(), but gives finer control over |
| * how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */ |
| ZSTDLIB_API size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType); |
| |
| /*! ZSTD_DCtx_setMaxWindowSize() : |
| * Refuses allocating internal buffers for frames requiring a window size larger than provided limit. |
| * This protects a decoder context from reserving too much memory for itself (potential attack scenario). |
| * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode. |
| * By default, a decompression context accepts all window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT) |
| * @return : 0, or an error code (which can be tested using ZSTD_isError()). |
| */ |
| ZSTDLIB_API size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize); |
| |
| /*! ZSTD_DCtx_getParameter() : |
| * Get the requested decompression parameter value, selected by enum ZSTD_dParameter, |
| * and store it into int* value. |
| * @return : 0, or an error code (which can be tested with ZSTD_isError()). |
| */ |
| ZSTDLIB_API size_t ZSTD_DCtx_getParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int* value); |
| |
| /* ZSTD_d_format |
| * experimental parameter, |
| * allowing selection between ZSTD_format_e input compression formats |
| */ |
| #define ZSTD_d_format ZSTD_d_experimentalParam1 |
| /* ZSTD_d_stableOutBuffer |
| * Experimental parameter. |
| * Default is 0 == disabled. Set to 1 to enable. |
| * |
| * Tells the decompressor that the ZSTD_outBuffer will ALWAYS be the same |
| * between calls, except for the modifications that zstd makes to pos (the |
| * caller must not modify pos). This is checked by the decompressor, and |
| * decompression will fail if it ever changes. Therefore the ZSTD_outBuffer |
| * MUST be large enough to fit the entire decompressed frame. This will be |
| * checked when the frame content size is known. The data in the ZSTD_outBuffer |
| * in the range [dst, dst + pos) MUST not be modified during decompression |
| * or you will get data corruption. |
| * |
| * When this flags is enabled zstd won't allocate an output buffer, because |
| * it can write directly to the ZSTD_outBuffer, but it will still allocate |
| * an input buffer large enough to fit any compressed block. This will also |
| * avoid the memcpy() from the internal output buffer to the ZSTD_outBuffer. |
| * If you need to avoid the input buffer allocation use the buffer-less |
| * streaming API. |
| * |
| * NOTE: So long as the ZSTD_outBuffer always points to valid memory, using |
| * this flag is ALWAYS memory safe, and will never access out-of-bounds |
| * memory. However, decompression WILL fail if you violate the preconditions. |
| * |
| * WARNING: The data in the ZSTD_outBuffer in the range [dst, dst + pos) MUST |
| * not be modified during decompression or you will get data corruption. This |
| * is because zstd needs to reference data in the ZSTD_outBuffer to regenerate |
| * matches. Normally zstd maintains its own buffer for this purpose, but passing |
| * this flag tells zstd to use the user provided buffer. |
| */ |
| #define ZSTD_d_stableOutBuffer ZSTD_d_experimentalParam2 |
| |
| /* ZSTD_d_forceIgnoreChecksum |
| * Experimental parameter. |
| * Default is 0 == disabled. Set to 1 to enable |
| * |
| * Tells the decompressor to skip checksum validation during decompression, regardless |
| * of whether checksumming was specified during compression. This offers some |
| * slight performance benefits, and may be useful for debugging. |
| * Param has values of type ZSTD_forceIgnoreChecksum_e |
| */ |
| #define ZSTD_d_forceIgnoreChecksum ZSTD_d_experimentalParam3 |
| |
| /* ZSTD_d_refMultipleDDicts |
| * Experimental parameter. |
| * Default is 0 == disabled. Set to 1 to enable |
| * |
| * If enabled and dctx is allocated on the heap, then additional memory will be allocated |
| * to store references to multiple ZSTD_DDict. That is, multiple calls of ZSTD_refDDict() |
| * using a given ZSTD_DCtx, rather than overwriting the previous DDict reference, will instead |
| * store all references. At decompression time, the appropriate dictID is selected |
| * from the set of DDicts based on the dictID in the frame. |
| * |
| * Usage is simply calling ZSTD_refDDict() on multiple dict buffers. |
| * |
| * Param has values of byte ZSTD_refMultipleDDicts_e |
| * |
| * WARNING: Enabling this parameter and calling ZSTD_DCtx_refDDict(), will trigger memory |
| * allocation for the hash table. ZSTD_freeDCtx() also frees this memory. |
| * Memory is allocated as per ZSTD_DCtx::customMem. |
| * |
| * Although this function allocates memory for the table, the user is still responsible for |
| * memory management of the underlying ZSTD_DDict* themselves. |
| */ |
| #define ZSTD_d_refMultipleDDicts ZSTD_d_experimentalParam4 |
| |
| |
| /*! ZSTD_DCtx_setFormat() : |
| * Instruct the decoder context about what kind of data to decode next. |
| * This instruction is mandatory to decode data without a fully-formed header, |
| * such ZSTD_f_zstd1_magicless for example. |
| * @return : 0, or an error code (which can be tested using ZSTD_isError()). */ |
| ZSTDLIB_API size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format); |
| |
| /*! ZSTD_decompressStream_simpleArgs() : |
| * Same as ZSTD_decompressStream(), |
| * but using only integral types as arguments. |
| * This can be helpful for binders from dynamic languages |
| * which have troubles handling structures containing memory pointers. |
| */ |
| ZSTDLIB_API size_t ZSTD_decompressStream_simpleArgs ( |
| ZSTD_DCtx* dctx, |
| void* dst, size_t dstCapacity, size_t* dstPos, |
| const void* src, size_t srcSize, size_t* srcPos); |
| |
| |
| /* ****************************************************************** |
| * Advanced streaming functions |
| * Warning : most of these functions are now redundant with the Advanced API. |
| * Once Advanced API reaches "stable" status, |
| * redundant functions will be deprecated, and then at some point removed. |
| ********************************************************************/ |
| |
| /*===== Advanced Streaming compression functions =====*/ |
| |
| /*! ZSTD_initCStream_srcSize() : |
| * This function is deprecated, and equivalent to: |
| * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); |
| * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any) |
| * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); |
| * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); |
| * |
| * pledgedSrcSize must be correct. If it is not known at init time, use |
| * ZSTD_CONTENTSIZE_UNKNOWN. Note that, for compatibility with older programs, |
| * "0" also disables frame content size field. It may be enabled in the future. |
| * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x |
| */ |
| ZSTDLIB_API size_t |
| ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, |
| int compressionLevel, |
| unsigned long long pledgedSrcSize); |
| |
| /*! ZSTD_initCStream_usingDict() : |
| * This function is deprecated, and is equivalent to: |
| * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); |
| * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); |
| * ZSTD_CCtx_loadDictionary(zcs, dict, dictSize); |
| * |
| * Creates of an internal CDict (incompatible with static CCtx), except if |
| * dict == NULL or dictSize < 8, in which case no dict is used. |
| * Note: dict is loaded with ZSTD_dct_auto (treated as a full zstd dictionary if |
| * it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy. |
| * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x |
| */ |
| ZSTDLIB_API size_t |
| ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, |
| const void* dict, size_t dictSize, |
| int compressionLevel); |
| |
| /*! ZSTD_initCStream_advanced() : |
| * This function is deprecated, and is approximately equivalent to: |
| * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); |
| * // Pseudocode: Set each zstd parameter and leave the rest as-is. |
| * for ((param, value) : params) { |
| * ZSTD_CCtx_setParameter(zcs, param, value); |
| * } |
| * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); |
| * ZSTD_CCtx_loadDictionary(zcs, dict, dictSize); |
| * |
| * dict is loaded with ZSTD_dct_auto and ZSTD_dlm_byCopy. |
| * pledgedSrcSize must be correct. |
| * If srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN. |
| * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x |
| */ |
| ZSTDLIB_API size_t |
| ZSTD_initCStream_advanced(ZSTD_CStream* zcs, |
| const void* dict, size_t dictSize, |
| ZSTD_parameters params, |
| unsigned long long pledgedSrcSize); |
| |
| /*! ZSTD_initCStream_usingCDict() : |
| * This function is deprecated, and equivalent to: |
| * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); |
| * ZSTD_CCtx_refCDict(zcs, cdict); |
| * |
| * note : cdict will just be referenced, and must outlive compression session |
| * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x |
| */ |
| ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict); |
| |
| /*! ZSTD_initCStream_usingCDict_advanced() : |
| * This function is DEPRECATED, and is approximately equivalent to: |
| * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); |
| * // Pseudocode: Set each zstd frame parameter and leave the rest as-is. |
| * for ((fParam, value) : fParams) { |
| * ZSTD_CCtx_setParameter(zcs, fParam, value); |
| * } |
| * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); |
| * ZSTD_CCtx_refCDict(zcs, cdict); |
| * |
| * same as ZSTD_initCStream_usingCDict(), with control over frame parameters. |
| * pledgedSrcSize must be correct. If srcSize is not known at init time, use |
| * value ZSTD_CONTENTSIZE_UNKNOWN. |
| * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x |
| */ |
| ZSTDLIB_API size_t |
| ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, |
| const ZSTD_CDict* cdict, |
| ZSTD_frameParameters fParams, |
| unsigned long long pledgedSrcSize); |
| |
| /*! ZSTD_resetCStream() : |
| * This function is deprecated, and is equivalent to: |
| * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); |
| * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); |
| * |
| * start a new frame, using same parameters from previous frame. |
| * This is typically useful to skip dictionary loading stage, since it will re-use it in-place. |
| * Note that zcs must be init at least once before using ZSTD_resetCStream(). |
| * If pledgedSrcSize is not known at reset time, use macro ZSTD_CONTENTSIZE_UNKNOWN. |
| * If pledgedSrcSize > 0, its value must be correct, as it will be written in header, and controlled at the end. |
| * For the time being, pledgedSrcSize==0 is interpreted as "srcSize unknown" for compatibility with older programs, |
| * but it will change to mean "empty" in future version, so use macro ZSTD_CONTENTSIZE_UNKNOWN instead. |
| * @return : 0, or an error code (which can be tested using ZSTD_isError()) |
| * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x |
| */ |
| ZSTDLIB_API size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); |
| |
| |
| typedef struct { |
| unsigned long long ingested; /* nb input bytes read and buffered */ |
| unsigned long long consumed; /* nb input bytes actually compressed */ |
| unsigned long long produced; /* nb of compressed bytes generated and buffered */ |
| unsigned long long flushed; /* nb of compressed bytes flushed : not provided; can be tracked from caller side */ |
| unsigned currentJobID; /* MT only : latest started job nb */ |
| unsigned nbActiveWorkers; /* MT only : nb of workers actively compressing at probe time */ |
| } ZSTD_frameProgression; |
| |
| /* ZSTD_getFrameProgression() : |
| * tells how much data has been ingested (read from input) |
| * consumed (input actually compressed) and produced (output) for current frame. |
| * Note : (ingested - consumed) is amount of input data buffered internally, not yet compressed. |
| * Aggregates progression inside active worker threads. |
| */ |
| ZSTDLIB_API ZSTD_frameProgression ZSTD_getFrameProgression(const ZSTD_CCtx* cctx); |
| |
| /*! ZSTD_toFlushNow() : |
| * Tell how many bytes are ready to be flushed immediately. |
| * Useful for multithreading scenarios (nbWorkers >= 1). |
| * Probe the oldest active job, defined as oldest job not yet entirely flushed, |
| * and check its output buffer. |
| * @return : amount of data stored in oldest job and ready to be flushed immediately. |
| * if @return == 0, it means either : |
| * + there is no active job (could be checked with ZSTD_frameProgression()), or |
| * + oldest job is still actively compressing data, |
| * but everything it has produced has also been flushed so far, |
| * therefore flush speed is limited by production speed of oldest job |
| * irrespective of the speed of concurrent (and newer) jobs. |
| */ |
| ZSTDLIB_API size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx); |
| |
| |
| /*===== Advanced Streaming decompression functions =====*/ |
| |
| /*! |
| * This function is deprecated, and is equivalent to: |
| * |
| * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); |
| * ZSTD_DCtx_loadDictionary(zds, dict, dictSize); |
| * |
| * note: no dictionary will be used if dict == NULL or dictSize < 8 |
| * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x |
| */ |
| ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); |
| |
| /*! |
| * This function is deprecated, and is equivalent to: |
| * |
| * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); |
| * ZSTD_DCtx_refDDict(zds, ddict); |
| * |
| * note : ddict is referenced, it must outlive decompression session |
| * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x |
| */ |
| ZSTDLIB_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); |
| |
| /*! |
| * This function is deprecated, and is equivalent to: |
| * |
| * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); |
| * |
| * re-use decompression parameters from previous init; saves dictionary loading |
| * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x |
| */ |
| ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds); |
| |
| |
| /* ******************************************************************* |
| * Buffer-less and synchronous inner streaming functions |
| * |
| * This is an advanced API, giving full control over buffer management, for users which need direct control over memory. |
| * But it's also a complex one, with several restrictions, documented below. |
| * Prefer normal streaming API for an easier experience. |
| ********************************************************************* */ |
| |
| /* |
| Buffer-less streaming compression (synchronous mode) |
| |
| A ZSTD_CCtx object is required to track streaming operations. |
| Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource. |
| ZSTD_CCtx object can be re-used multiple times within successive compression operations. |
| |
| Start by initializing a context. |
| Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary compression, |
| or ZSTD_compressBegin_advanced(), for finer parameter control. |
| It's also possible to duplicate a reference context which has already been initialized, using ZSTD_copyCCtx() |
| |
| Then, consume your input using ZSTD_compressContinue(). |
| There are some important considerations to keep in mind when using this advanced function : |
| - ZSTD_compressContinue() has no internal buffer. It uses externally provided buffers only. |
| - Interface is synchronous : input is consumed entirely and produces 1+ compressed blocks. |
| - Caller must ensure there is enough space in `dst` to store compressed data under worst case scenario. |
| Worst case evaluation is provided by ZSTD_compressBound(). |
| ZSTD_compressContinue() doesn't guarantee recover after a failed compression. |
| - ZSTD_compressContinue() presumes prior input ***is still accessible and unmodified*** (up to maximum distance size, see WindowLog). |
| It remembers all previous contiguous blocks, plus one separated memory segment (which can itself consists of multiple contiguous blocks) |
| - ZSTD_compressContinue() detects that prior input has been overwritten when `src` buffer overlaps. |
| In which case, it will "discard" the relevant memory section from its history. |
| |
| Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum. |
| It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame. |
| Without last block mark, frames are considered unfinished (hence corrupted) by compliant decoders. |
| |
| `ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress again. |
| */ |
| |
| /*===== Buffer-less streaming compression functions =====*/ |
| ZSTDLIB_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel); |
| ZSTDLIB_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel); |
| ZSTDLIB_API size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize); /*< pledgedSrcSize : If srcSize is not known at init time, use ZSTD_CONTENTSIZE_UNKNOWN */ |
| ZSTDLIB_API size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); /*< note: fails if cdict==NULL */ |
| ZSTDLIB_API size_t ZSTD_compressBegin_usingCDict_advanced(ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict, ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize); /* compression parameters are already set within cdict. pledgedSrcSize must be correct. If srcSize is not known, use macro ZSTD_CONTENTSIZE_UNKNOWN */ |
| ZSTDLIB_API size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); /*< note: if pledgedSrcSize is not known, use ZSTD_CONTENTSIZE_UNKNOWN */ |
| |
| ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); |
| ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); |
| |
| |
| /* |
| Buffer-less streaming decompression (synchronous mode) |
| |
| A ZSTD_DCtx object is required to track streaming operations. |
| Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it. |
| A ZSTD_DCtx object can be re-used multiple times. |
| |
| First typical operation is to retrieve frame parameters, using ZSTD_getFrameHeader(). |
| Frame header is extracted from the beginning of compressed frame, so providing only the frame's beginning is enough. |
| Data fragment must be large enough to ensure successful decoding. |
| `ZSTD_frameHeaderSize_max` bytes is guaranteed to always be large enough. |
| @result : 0 : successful decoding, the `ZSTD_frameHeader` structure is correctly filled. |
| >0 : `srcSize` is too small, please provide at least @result bytes on next attempt. |
| errorCode, which can be tested using ZSTD_isError(). |
| |
| It fills a ZSTD_frameHeader structure with important information to correctly decode the frame, |
| such as the dictionary ID, content size, or maximum back-reference distance (`windowSize`). |
| Note that these values could be wrong, either because of data corruption, or because a 3rd party deliberately spoofs false information. |
| As a consequence, check that values remain within valid application range. |
| For example, do not allocate memory blindly, check that `windowSize` is within expectation. |
| Each application can set its own limits, depending on local restrictions. |
| For extended interoperability, it is recommended to support `windowSize` of at least 8 MB. |
| |
| ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize` bytes. |
| ZSTD_decompressContinue() is very sensitive to contiguity, |
| if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place, |
| or that previous contiguous segment is large enough to properly handle maximum back-reference distance. |
| There are multiple ways to guarantee this condition. |
| |
| The most memory efficient way is to use a round buffer of sufficient size. |
| Sufficient size is determined by invoking ZSTD_decodingBufferSize_min(), |
| which can @return an error code if required value is too large for current system (in 32-bits mode). |
| In a round buffer methodology, ZSTD_decompressContinue() decompresses each block next to previous one, |
| up to the moment there is not enough room left in the buffer to guarantee decoding another full block, |
| which maximum size is provided in `ZSTD_frameHeader` structure, field `blockSizeMax`. |
| At which point, decoding can resume from the beginning of the buffer. |
| Note that already decoded data stored in the buffer should be flushed before being overwritten. |
| |
| There are alternatives possible, for example using two or more buffers of size `windowSize` each, though they consume more memory. |
| |
| Finally, if you control the compression process, you can also ignore all buffer size rules, |
| as long as the encoder and decoder progress in "lock-step", |
| aka use exactly the same buffer sizes, break contiguity at the same place, etc. |
| |
| Once buffers are setup, start decompression, with ZSTD_decompressBegin(). |
| If decompression requires a dictionary, use ZSTD_decompressBegin_usingDict() or ZSTD_decompressBegin_usingDDict(). |
| |
| Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively. |
| ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize' to ZSTD_decompressContinue(). |
| ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will fail. |
| |
| @result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity). |
| It can be zero : it just means ZSTD_decompressContinue() has decoded some metadata item. |
| It can also be an error code, which can be tested with ZSTD_isError(). |
| |
| A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero. |
| Context can then be reset to start a new decompression. |
| |
| Note : it's possible to know if next input to present is a header or a block, using ZSTD_nextInputType(). |
| This information is not required to properly decode a frame. |
| |
| == Special case : skippable frames == |
| |
| Skippable frames allow integration of user-defined data into a flow of concatenated frames. |
| Skippable frames will be ignored (skipped) by decompressor. |
| The format of skippable frames is as follows : |
| a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F |
| b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits |
| c) Frame Content - any content (User Data) of length equal to Frame Size |
| For skippable frames ZSTD_getFrameHeader() returns zfhPtr->frameType==ZSTD_skippableFrame. |
| For skippable frames ZSTD_decompressContinue() always returns 0 : it only skips the content. |
| */ |
| |
| /*===== Buffer-less streaming decompression functions =====*/ |
| typedef enum { ZSTD_frame, ZSTD_skippableFrame } ZSTD_frameType_e; |
| typedef struct { |
| unsigned long long frameContentSize; /* if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty" */ |
| unsigned long long windowSize; /* can be very large, up to <= frameContentSize */ |
| unsigned blockSizeMax; |
| ZSTD_frameType_e frameType; /* if == ZSTD_skippableFrame, frameContentSize is the size of skippable content */ |
| unsigned headerSize; |
| unsigned dictID; |
| unsigned checksumFlag; |
| } ZSTD_frameHeader; |
| |
| /*! ZSTD_getFrameHeader() : |
| * decode Frame Header, or requires larger `srcSize`. |
| * @return : 0, `zfhPtr` is correctly filled, |
| * >0, `srcSize` is too small, value is wanted `srcSize` amount, |
| * or an error code, which can be tested using ZSTD_isError() */ |
| ZSTDLIB_API size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); /*< doesn't consume input */ |
| /*! ZSTD_getFrameHeader_advanced() : |
| * same as ZSTD_getFrameHeader(), |
| * with added capability to select a format (like ZSTD_f_zstd1_magicless) */ |
| ZSTDLIB_API size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize, ZSTD_format_e format); |
| ZSTDLIB_API size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize); /*< when frame content size is not known, pass in frameContentSize == ZSTD_CONTENTSIZE_UNKNOWN */ |
| |
| ZSTDLIB_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx); |
| ZSTDLIB_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); |
| ZSTDLIB_API size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); |
| |
| ZSTDLIB_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx); |
| ZSTDLIB_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); |
| |
| /* misc */ |
| ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx); |
| typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e; |
| ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx); |
| |
| |
| |
| |
| /* ============================ */ |
| /* Block level API */ |
| /* ============================ */ |
| |
| /*! |
| Block functions produce and decode raw zstd blocks, without frame metadata. |
| Frame metadata cost is typically ~12 bytes, which can be non-negligible for very small blocks (< 100 bytes). |
| But users will have to take in charge needed metadata to regenerate data, such as compressed and content sizes. |
| |
| A few rules to respect : |
| - Compressing and decompressing require a context structure |
| + Use ZSTD_createCCtx() and ZSTD_createDCtx() |
| - It is necessary to init context before starting |
| + compression : any ZSTD_compressBegin*() variant, including with dictionary |
| + decompression : any ZSTD_decompressBegin*() variant, including with dictionary |
| + copyCCtx() and copyDCtx() can be used too |
| - Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX == 128 KB |
| + If input is larger than a block size, it's necessary to split input data into multiple blocks |
| + For inputs larger than a single block, consider using regular ZSTD_compress() instead. |
| Frame metadata is not that costly, and quickly becomes negligible as source size grows larger than a block. |
| - When a block is considered not compressible enough, ZSTD_compressBlock() result will be 0 (zero) ! |
| ===> In which case, nothing is produced into `dst` ! |
| + User __must__ test for such outcome and deal directly with uncompressed data |
| + A block cannot be declared incompressible if ZSTD_compressBlock() return value was != 0. |
| Doing so would mess up with statistics history, leading to potential data corruption. |
| + ZSTD_decompressBlock() _doesn't accept uncompressed data as input_ !! |
| + In case of multiple successive blocks, should some of them be uncompressed, |
| decoder must be informed of their existence in order to follow proper history. |
| Use ZSTD_insertBlock() for such a case. |
| */ |
| |
| /*===== Raw zstd block functions =====*/ |
| ZSTDLIB_API size_t ZSTD_getBlockSize (const ZSTD_CCtx* cctx); |
| ZSTDLIB_API size_t ZSTD_compressBlock (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); |
| ZSTDLIB_API size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); |
| ZSTDLIB_API size_t ZSTD_insertBlock (ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize); /*< insert uncompressed block into `dctx` history. Useful for multi-blocks decompression. */ |
| |
| |
| #endif /* ZSTD_H_ZSTD_STATIC_LINKING_ONLY */ |
| |