| /* |
| * LZ4 Decompressor for Linux kernel |
| * |
| * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com> |
| * |
| * Based on LZ4 implementation by Yann Collet. |
| * |
| * LZ4 - Fast LZ compression algorithm |
| * Copyright (C) 2011-2012, Yann Collet. |
| * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| * You can contact the author at : |
| * - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html |
| * - LZ4 source repository : http://code.google.com/p/lz4/ |
| */ |
| |
| #ifndef STATIC |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| #endif |
| #include <linux/lz4.h> |
| |
| #include <asm/unaligned.h> |
| |
| #include "lz4defs.h" |
| |
| static int lz4_uncompress(const char *source, char *dest, int osize) |
| { |
| const BYTE *ip = (const BYTE *) source; |
| const BYTE *ref; |
| BYTE *op = (BYTE *) dest; |
| BYTE * const oend = op + osize; |
| BYTE *cpy; |
| unsigned token; |
| size_t length; |
| size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; |
| #if LZ4_ARCH64 |
| size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; |
| #endif |
| |
| while (1) { |
| |
| /* get runlength */ |
| token = *ip++; |
| length = (token >> ML_BITS); |
| if (length == RUN_MASK) { |
| size_t len; |
| |
| len = *ip++; |
| for (; len == 255; length += 255) |
| len = *ip++; |
| if (unlikely(length > (size_t)(length + len))) |
| goto _output_error; |
| length += len; |
| } |
| |
| /* copy literals */ |
| cpy = op + length; |
| if (unlikely(cpy > oend - COPYLENGTH)) { |
| /* |
| * Error: not enough place for another match |
| * (min 4) + 5 literals |
| */ |
| if (cpy != oend) |
| goto _output_error; |
| |
| memcpy(op, ip, length); |
| ip += length; |
| break; /* EOF */ |
| } |
| LZ4_WILDCOPY(ip, op, cpy); |
| ip -= (op - cpy); |
| op = cpy; |
| |
| /* get offset */ |
| LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); |
| ip += 2; |
| |
| /* Error: offset create reference outside destination buffer */ |
| if (unlikely(ref < (BYTE *const) dest)) |
| goto _output_error; |
| |
| /* get matchlength */ |
| length = token & ML_MASK; |
| if (length == ML_MASK) { |
| for (; *ip == 255; length += 255) |
| ip++; |
| length += *ip++; |
| } |
| |
| /* copy repeated sequence */ |
| if (unlikely((op - ref) < STEPSIZE)) { |
| #if LZ4_ARCH64 |
| size_t dec64 = dec64table[op - ref]; |
| #else |
| const int dec64 = 0; |
| #endif |
| op[0] = ref[0]; |
| op[1] = ref[1]; |
| op[2] = ref[2]; |
| op[3] = ref[3]; |
| op += 4; |
| ref += 4; |
| ref -= dec32table[op-ref]; |
| PUT4(ref, op); |
| op += STEPSIZE - 4; |
| ref -= dec64; |
| } else { |
| LZ4_COPYSTEP(ref, op); |
| } |
| cpy = op + length - (STEPSIZE - 4); |
| if (cpy > (oend - COPYLENGTH)) { |
| |
| /* Error: request to write beyond destination buffer */ |
| if (cpy > oend) |
| goto _output_error; |
| LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); |
| while (op < cpy) |
| *op++ = *ref++; |
| op = cpy; |
| /* |
| * Check EOF (should never happen, since last 5 bytes |
| * are supposed to be literals) |
| */ |
| if (op == oend) |
| goto _output_error; |
| continue; |
| } |
| LZ4_SECURECOPY(ref, op, cpy); |
| op = cpy; /* correction */ |
| } |
| /* end of decoding */ |
| return (int) (((char *)ip) - source); |
| |
| /* write overflow error detected */ |
| _output_error: |
| return (int) (-(((char *)ip) - source)); |
| } |
| |
| static int lz4_uncompress_unknownoutputsize(const char *source, char *dest, |
| int isize, size_t maxoutputsize) |
| { |
| const BYTE *ip = (const BYTE *) source; |
| const BYTE *const iend = ip + isize; |
| const BYTE *ref; |
| |
| |
| BYTE *op = (BYTE *) dest; |
| BYTE * const oend = op + maxoutputsize; |
| BYTE *cpy; |
| |
| size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0}; |
| #if LZ4_ARCH64 |
| size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3}; |
| #endif |
| |
| /* Main Loop */ |
| while (ip < iend) { |
| |
| unsigned token; |
| size_t length; |
| |
| /* get runlength */ |
| token = *ip++; |
| length = (token >> ML_BITS); |
| if (length == RUN_MASK) { |
| int s = 255; |
| while ((ip < iend) && (s == 255)) { |
| s = *ip++; |
| length += s; |
| } |
| } |
| /* copy literals */ |
| cpy = op + length; |
| if ((cpy > oend - COPYLENGTH) || |
| (ip + length > iend - COPYLENGTH)) { |
| |
| if (cpy > oend) |
| goto _output_error;/* writes beyond buffer */ |
| |
| if (ip + length != iend) |
| goto _output_error;/* |
| * Error: LZ4 format requires |
| * to consume all input |
| * at this stage |
| */ |
| memcpy(op, ip, length); |
| op += length; |
| break;/* Necessarily EOF, due to parsing restrictions */ |
| } |
| LZ4_WILDCOPY(ip, op, cpy); |
| ip -= (op - cpy); |
| op = cpy; |
| |
| /* get offset */ |
| LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip); |
| ip += 2; |
| if (ref < (BYTE * const) dest) |
| goto _output_error; |
| /* |
| * Error : offset creates reference |
| * outside of destination buffer |
| */ |
| |
| /* get matchlength */ |
| length = (token & ML_MASK); |
| if (length == ML_MASK) { |
| while (ip < iend) { |
| int s = *ip++; |
| length += s; |
| if (s == 255) |
| continue; |
| break; |
| } |
| } |
| |
| /* copy repeated sequence */ |
| if (unlikely((op - ref) < STEPSIZE)) { |
| #if LZ4_ARCH64 |
| size_t dec64 = dec64table[op - ref]; |
| #else |
| const int dec64 = 0; |
| #endif |
| op[0] = ref[0]; |
| op[1] = ref[1]; |
| op[2] = ref[2]; |
| op[3] = ref[3]; |
| op += 4; |
| ref += 4; |
| ref -= dec32table[op - ref]; |
| PUT4(ref, op); |
| op += STEPSIZE - 4; |
| ref -= dec64; |
| } else { |
| LZ4_COPYSTEP(ref, op); |
| } |
| cpy = op + length - (STEPSIZE-4); |
| if (cpy > oend - COPYLENGTH) { |
| if (cpy > oend) |
| goto _output_error; /* write outside of buf */ |
| |
| LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH)); |
| while (op < cpy) |
| *op++ = *ref++; |
| op = cpy; |
| /* |
| * Check EOF (should never happen, since last 5 bytes |
| * are supposed to be literals) |
| */ |
| if (op == oend) |
| goto _output_error; |
| continue; |
| } |
| LZ4_SECURECOPY(ref, op, cpy); |
| op = cpy; /* correction */ |
| } |
| /* end of decoding */ |
| return (int) (((char *) op) - dest); |
| |
| /* write overflow error detected */ |
| _output_error: |
| return (int) (-(((char *) ip) - source)); |
| } |
| |
| int lz4_decompress(const unsigned char *src, size_t *src_len, |
| unsigned char *dest, size_t actual_dest_len) |
| { |
| int ret = -1; |
| int input_len = 0; |
| |
| input_len = lz4_uncompress(src, dest, actual_dest_len); |
| if (input_len < 0) |
| goto exit_0; |
| *src_len = input_len; |
| |
| return 0; |
| exit_0: |
| return ret; |
| } |
| #ifndef STATIC |
| EXPORT_SYMBOL(lz4_decompress); |
| #endif |
| |
| int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len, |
| unsigned char *dest, size_t *dest_len) |
| { |
| int ret = -1; |
| int out_len = 0; |
| |
| out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len, |
| *dest_len); |
| if (out_len < 0) |
| goto exit_0; |
| *dest_len = out_len; |
| |
| return 0; |
| exit_0: |
| return ret; |
| } |
| #ifndef STATIC |
| EXPORT_SYMBOL(lz4_decompress_unknownoutputsize); |
| |
| MODULE_LICENSE("Dual BSD/GPL"); |
| MODULE_DESCRIPTION("LZ4 Decompressor"); |
| #endif |