| /* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */ |
| /* |
| * 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 https://github.com/facebook/zstd) and |
| * the GPLv2 (found in the COPYING file in the root directory of |
| * https://github.com/facebook/zstd). You may select, at your option, one of the |
| * above-listed licenses. |
| */ |
| |
| #ifndef LINUX_ZSTD_H |
| #define LINUX_ZSTD_H |
| |
| /** |
| * This is a kernel-style API that wraps the upstream zstd API, which cannot be |
| * used directly because the symbols aren't exported. It exposes the minimal |
| * functionality which is currently required by users of zstd in the kernel. |
| * Expose extra functions from lib/zstd/zstd.h as needed. |
| */ |
| |
| /* ====== Dependency ====== */ |
| #include <linux/types.h> |
| #include <linux/zstd_errors.h> |
| #include <linux/zstd_lib.h> |
| |
| /* ====== Helper Functions ====== */ |
| /** |
| * zstd_compress_bound() - maximum compressed size in worst case scenario |
| * @src_size: The size of the data to compress. |
| * |
| * Return: The maximum compressed size in the worst case scenario. |
| */ |
| size_t zstd_compress_bound(size_t src_size); |
| |
| /** |
| * zstd_is_error() - tells if a size_t function result is an error code |
| * @code: The function result to check for error. |
| * |
| * Return: Non-zero iff the code is an error. |
| */ |
| unsigned int zstd_is_error(size_t code); |
| |
| /** |
| * enum zstd_error_code - zstd error codes |
| */ |
| typedef ZSTD_ErrorCode zstd_error_code; |
| |
| /** |
| * zstd_get_error_code() - translates an error function result to an error code |
| * @code: The function result for which zstd_is_error(code) is true. |
| * |
| * Return: A unique error code for this error. |
| */ |
| zstd_error_code zstd_get_error_code(size_t code); |
| |
| /** |
| * zstd_get_error_name() - translates an error function result to a string |
| * @code: The function result for which zstd_is_error(code) is true. |
| * |
| * Return: An error string corresponding to the error code. |
| */ |
| const char *zstd_get_error_name(size_t code); |
| |
| /** |
| * zstd_min_clevel() - minimum allowed compression level |
| * |
| * Return: The minimum allowed compression level. |
| */ |
| int zstd_min_clevel(void); |
| |
| /** |
| * zstd_max_clevel() - maximum allowed compression level |
| * |
| * Return: The maximum allowed compression level. |
| */ |
| int zstd_max_clevel(void); |
| |
| /* ====== Parameter Selection ====== */ |
| |
| /** |
| * enum zstd_strategy - zstd compression search strategy |
| * |
| * From faster to stronger. See zstd_lib.h. |
| */ |
| typedef ZSTD_strategy zstd_strategy; |
| |
| /** |
| * struct zstd_compression_parameters - zstd compression parameters |
| * @windowLog: Log of the largest match distance. Larger means more |
| * compression, and more memory needed during decompression. |
| * @chainLog: Fully searched segment. Larger means more compression, |
| * slower, and more memory (useless for fast). |
| * @hashLog: Dispatch table. Larger means more compression, |
| * slower, and more memory. |
| * @searchLog: Number of searches. Larger means more compression and slower. |
| * @searchLength: Match length searched. Larger means faster decompression, |
| * sometimes less compression. |
| * @targetLength: Acceptable match size for optimal parser (only). Larger means |
| * more compression, and slower. |
| * @strategy: The zstd compression strategy. |
| * |
| * See zstd_lib.h. |
| */ |
| typedef ZSTD_compressionParameters zstd_compression_parameters; |
| |
| /** |
| * struct zstd_frame_parameters - zstd frame parameters |
| * @contentSizeFlag: Controls whether content size will be present in the |
| * frame header (when known). |
| * @checksumFlag: Controls whether a 32-bit checksum is generated at the |
| * end of the frame for error detection. |
| * @noDictIDFlag: Controls whether dictID will be saved into the frame |
| * header when using dictionary compression. |
| * |
| * The default value is all fields set to 0. See zstd_lib.h. |
| */ |
| typedef ZSTD_frameParameters zstd_frame_parameters; |
| |
| /** |
| * struct zstd_parameters - zstd parameters |
| * @cParams: The compression parameters. |
| * @fParams: The frame parameters. |
| */ |
| typedef ZSTD_parameters zstd_parameters; |
| |
| /** |
| * zstd_get_params() - returns zstd_parameters for selected level |
| * @level: The compression level |
| * @estimated_src_size: The estimated source size to compress or 0 |
| * if unknown. |
| * |
| * Return: The selected zstd_parameters. |
| */ |
| zstd_parameters zstd_get_params(int level, |
| unsigned long long estimated_src_size); |
| |
| /* ====== Single-pass Compression ====== */ |
| |
| typedef ZSTD_CCtx zstd_cctx; |
| |
| /** |
| * zstd_cctx_workspace_bound() - max memory needed to initialize a zstd_cctx |
| * @parameters: The compression parameters to be used. |
| * |
| * If multiple compression parameters might be used, the caller must call |
| * zstd_cctx_workspace_bound() for each set of parameters and use the maximum |
| * size. |
| * |
| * Return: A lower bound on the size of the workspace that is passed to |
| * zstd_init_cctx(). |
| */ |
| size_t zstd_cctx_workspace_bound(const zstd_compression_parameters *parameters); |
| |
| /** |
| * zstd_init_cctx() - initialize a zstd compression context |
| * @workspace: The workspace to emplace the context into. It must outlive |
| * the returned context. |
| * @workspace_size: The size of workspace. Use zstd_cctx_workspace_bound() to |
| * determine how large the workspace must be. |
| * |
| * Return: A zstd compression context or NULL on error. |
| */ |
| zstd_cctx *zstd_init_cctx(void *workspace, size_t workspace_size); |
| |
| /** |
| * zstd_compress_cctx() - compress src into dst with the initialized parameters |
| * @cctx: The context. Must have been initialized with zstd_init_cctx(). |
| * @dst: The buffer to compress src into. |
| * @dst_capacity: The size of the destination buffer. May be any size, but |
| * ZSTD_compressBound(srcSize) is guaranteed to be large enough. |
| * @src: The data to compress. |
| * @src_size: The size of the data to compress. |
| * @parameters: The compression parameters to be used. |
| * |
| * Return: The compressed size or an error, which can be checked using |
| * zstd_is_error(). |
| */ |
| size_t zstd_compress_cctx(zstd_cctx *cctx, void *dst, size_t dst_capacity, |
| const void *src, size_t src_size, const zstd_parameters *parameters); |
| |
| /* ====== Single-pass Decompression ====== */ |
| |
| typedef ZSTD_DCtx zstd_dctx; |
| |
| /** |
| * zstd_dctx_workspace_bound() - max memory needed to initialize a zstd_dctx |
| * |
| * Return: A lower bound on the size of the workspace that is passed to |
| * zstd_init_dctx(). |
| */ |
| size_t zstd_dctx_workspace_bound(void); |
| |
| /** |
| * zstd_init_dctx() - initialize a zstd decompression context |
| * @workspace: The workspace to emplace the context into. It must outlive |
| * the returned context. |
| * @workspace_size: The size of workspace. Use zstd_dctx_workspace_bound() to |
| * determine how large the workspace must be. |
| * |
| * Return: A zstd decompression context or NULL on error. |
| */ |
| zstd_dctx *zstd_init_dctx(void *workspace, size_t workspace_size); |
| |
| /** |
| * zstd_decompress_dctx() - decompress zstd compressed src into dst |
| * @dctx: The decompression context. |
| * @dst: The buffer to decompress src into. |
| * @dst_capacity: The size of the destination buffer. Must be at least as large |
| * as the decompressed size. If the caller cannot upper bound the |
| * decompressed size, then it's better to use the streaming API. |
| * @src: The zstd compressed data to decompress. Multiple concatenated |
| * frames and skippable frames are allowed. |
| * @src_size: The exact size of the data to decompress. |
| * |
| * Return: The decompressed size or an error, which can be checked using |
| * zstd_is_error(). |
| */ |
| size_t zstd_decompress_dctx(zstd_dctx *dctx, void *dst, size_t dst_capacity, |
| const void *src, size_t src_size); |
| |
| /* ====== Streaming Buffers ====== */ |
| |
| /** |
| * struct zstd_in_buffer - input buffer for streaming |
| * @src: Start of the input buffer. |
| * @size: Size of the input buffer. |
| * @pos: Position where reading stopped. Will be updated. |
| * Necessarily 0 <= pos <= size. |
| * |
| * See zstd_lib.h. |
| */ |
| typedef ZSTD_inBuffer zstd_in_buffer; |
| |
| /** |
| * struct zstd_out_buffer - output buffer for streaming |
| * @dst: Start of the output buffer. |
| * @size: Size of the output buffer. |
| * @pos: Position where writing stopped. Will be updated. |
| * Necessarily 0 <= pos <= size. |
| * |
| * See zstd_lib.h. |
| */ |
| typedef ZSTD_outBuffer zstd_out_buffer; |
| |
| /* ====== Streaming Compression ====== */ |
| |
| typedef ZSTD_CStream zstd_cstream; |
| |
| /** |
| * zstd_cstream_workspace_bound() - memory needed to initialize a zstd_cstream |
| * @cparams: The compression parameters to be used for compression. |
| * |
| * Return: A lower bound on the size of the workspace that is passed to |
| * zstd_init_cstream(). |
| */ |
| size_t zstd_cstream_workspace_bound(const zstd_compression_parameters *cparams); |
| |
| /** |
| * zstd_init_cstream() - initialize a zstd streaming compression context |
| * @parameters The zstd parameters to use for compression. |
| * @pledged_src_size: If params.fParams.contentSizeFlag == 1 then the caller |
| * must pass the source size (zero means empty source). |
| * Otherwise, the caller may optionally pass the source |
| * size, or zero if unknown. |
| * @workspace: The workspace to emplace the context into. It must outlive |
| * the returned context. |
| * @workspace_size: The size of workspace. |
| * Use zstd_cstream_workspace_bound(params->cparams) to |
| * determine how large the workspace must be. |
| * |
| * Return: The zstd streaming compression context or NULL on error. |
| */ |
| zstd_cstream *zstd_init_cstream(const zstd_parameters *parameters, |
| unsigned long long pledged_src_size, void *workspace, size_t workspace_size); |
| |
| /** |
| * zstd_reset_cstream() - reset the context using parameters from creation |
| * @cstream: The zstd streaming compression context to reset. |
| * @pledged_src_size: Optionally the source size, or zero if unknown. |
| * |
| * Resets the context using the parameters from creation. Skips dictionary |
| * loading, since it can be reused. If `pledged_src_size` is non-zero the frame |
| * content size is always written into the frame header. |
| * |
| * Return: Zero or an error, which can be checked using |
| * zstd_is_error(). |
| */ |
| size_t zstd_reset_cstream(zstd_cstream *cstream, |
| unsigned long long pledged_src_size); |
| |
| /** |
| * zstd_compress_stream() - streaming compress some of input into output |
| * @cstream: The zstd streaming compression context. |
| * @output: Destination buffer. `output->pos` is updated to indicate how much |
| * compressed data was written. |
| * @input: Source buffer. `input->pos` is updated to indicate how much data |
| * was read. Note that it may not consume the entire input, in which |
| * case `input->pos < input->size`, and it's up to the caller to |
| * present remaining data again. |
| * |
| * The `input` and `output` buffers may be any size. Guaranteed to make some |
| * forward progress if `input` and `output` are not empty. |
| * |
| * Return: A hint for the number of bytes to use as the input for the next |
| * function call or an error, which can be checked using |
| * zstd_is_error(). |
| */ |
| size_t zstd_compress_stream(zstd_cstream *cstream, zstd_out_buffer *output, |
| zstd_in_buffer *input); |
| |
| /** |
| * zstd_flush_stream() - flush internal buffers into output |
| * @cstream: The zstd streaming compression context. |
| * @output: Destination buffer. `output->pos` is updated to indicate how much |
| * compressed data was written. |
| * |
| * zstd_flush_stream() must be called until it returns 0, meaning all the data |
| * has been flushed. Since zstd_flush_stream() causes a block to be ended, |
| * calling it too often will degrade the compression ratio. |
| * |
| * Return: The number of bytes still present within internal buffers or an |
| * error, which can be checked using zstd_is_error(). |
| */ |
| size_t zstd_flush_stream(zstd_cstream *cstream, zstd_out_buffer *output); |
| |
| /** |
| * zstd_end_stream() - flush internal buffers into output and end the frame |
| * @cstream: The zstd streaming compression context. |
| * @output: Destination buffer. `output->pos` is updated to indicate how much |
| * compressed data was written. |
| * |
| * zstd_end_stream() must be called until it returns 0, meaning all the data has |
| * been flushed and the frame epilogue has been written. |
| * |
| * Return: The number of bytes still present within internal buffers or an |
| * error, which can be checked using zstd_is_error(). |
| */ |
| size_t zstd_end_stream(zstd_cstream *cstream, zstd_out_buffer *output); |
| |
| /* ====== Streaming Decompression ====== */ |
| |
| typedef ZSTD_DStream zstd_dstream; |
| |
| /** |
| * zstd_dstream_workspace_bound() - memory needed to initialize a zstd_dstream |
| * @max_window_size: The maximum window size allowed for compressed frames. |
| * |
| * Return: A lower bound on the size of the workspace that is passed |
| * to zstd_init_dstream(). |
| */ |
| size_t zstd_dstream_workspace_bound(size_t max_window_size); |
| |
| /** |
| * zstd_init_dstream() - initialize a zstd streaming decompression context |
| * @max_window_size: The maximum window size allowed for compressed frames. |
| * @workspace: The workspace to emplace the context into. It must outlive |
| * the returned context. |
| * @workspaceSize: The size of workspace. |
| * Use zstd_dstream_workspace_bound(max_window_size) to |
| * determine how large the workspace must be. |
| * |
| * Return: The zstd streaming decompression context. |
| */ |
| zstd_dstream *zstd_init_dstream(size_t max_window_size, void *workspace, |
| size_t workspace_size); |
| |
| /** |
| * zstd_reset_dstream() - reset the context using parameters from creation |
| * @dstream: The zstd streaming decompression context to reset. |
| * |
| * Resets the context using the parameters from creation. Skips dictionary |
| * loading, since it can be reused. |
| * |
| * Return: Zero or an error, which can be checked using zstd_is_error(). |
| */ |
| size_t zstd_reset_dstream(zstd_dstream *dstream); |
| |
| /** |
| * zstd_decompress_stream() - streaming decompress some of input into output |
| * @dstream: The zstd streaming decompression context. |
| * @output: Destination buffer. `output.pos` is updated to indicate how much |
| * decompressed data was written. |
| * @input: Source buffer. `input.pos` is updated to indicate how much data was |
| * read. Note that it may not consume the entire input, in which case |
| * `input.pos < input.size`, and it's up to the caller to present |
| * remaining data again. |
| * |
| * The `input` and `output` buffers may be any size. Guaranteed to make some |
| * forward progress if `input` and `output` are not empty. |
| * zstd_decompress_stream() will not consume the last byte of the frame until |
| * the entire frame is flushed. |
| * |
| * Return: Returns 0 iff a frame is completely decoded and fully flushed. |
| * Otherwise returns a hint for the number of bytes to use as the |
| * input for the next function call or an error, which can be checked |
| * using zstd_is_error(). The size hint will never load more than the |
| * frame. |
| */ |
| size_t zstd_decompress_stream(zstd_dstream *dstream, zstd_out_buffer *output, |
| zstd_in_buffer *input); |
| |
| /* ====== Frame Inspection Functions ====== */ |
| |
| /** |
| * zstd_find_frame_compressed_size() - returns the size of a compressed frame |
| * @src: Source buffer. It should point to the start of a zstd encoded |
| * frame or a skippable frame. |
| * @src_size: The size of the source buffer. It must be at least as large as the |
| * size of the frame. |
| * |
| * Return: The compressed size of the frame pointed to by `src` or an error, |
| * which can be check with zstd_is_error(). |
| * Suitable to pass to ZSTD_decompress() or similar functions. |
| */ |
| size_t zstd_find_frame_compressed_size(const void *src, size_t src_size); |
| |
| /** |
| * struct zstd_frame_params - zstd frame parameters stored in the frame header |
| * @frameContentSize: The frame content size, or ZSTD_CONTENTSIZE_UNKNOWN if not |
| * present. |
| * @windowSize: The window size, or 0 if the frame is a skippable frame. |
| * @blockSizeMax: The maximum block size. |
| * @frameType: The frame type (zstd or skippable) |
| * @headerSize: The size of the frame header. |
| * @dictID: The dictionary id, or 0 if not present. |
| * @checksumFlag: Whether a checksum was used. |
| * |
| * See zstd_lib.h. |
| */ |
| typedef ZSTD_frameHeader zstd_frame_header; |
| |
| /** |
| * zstd_get_frame_header() - extracts parameters from a zstd or skippable frame |
| * @params: On success the frame parameters are written here. |
| * @src: The source buffer. It must point to a zstd or skippable frame. |
| * @src_size: The size of the source buffer. |
| * |
| * Return: 0 on success. If more data is required it returns how many bytes |
| * must be provided to make forward progress. Otherwise it returns |
| * an error, which can be checked using zstd_is_error(). |
| */ |
| size_t zstd_get_frame_header(zstd_frame_header *params, const void *src, |
| size_t src_size); |
| |
| #endif /* LINUX_ZSTD_H */ |