/* * LZ4 Decompressor for Linux kernel * * Copyright (C) 2013, LG Electronics, Kyungsik Lee * * 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 #include #endif #include #include "lz4defs.h" static const int dec32table[8] = {0, 3, 2, 3, 0, 0, 0, 0}; #if LZ4_ARCH64 static const int dec64table[8] = {0, 0, 0, -1, 0, 1, 2, 3}; #else static const int dec64table[8] = {0, 0, 0, 0, 0, 0, 0, 0}; #endif static inline size_t get_length(const u8 **ip, size_t length) { if (length == LENGTH_LONG) { size_t len; do { length += (len = *(*ip)++); } while (len == 255); } return length; } static int lz4_uncompress(const u8 *source, u8 *dest, int osize) { const u8 *ip = source; const u8 *ref; u8 *op = dest; u8 * const oend = op + osize; u8 *cpy; unsigned token, offset; ssize_t length; while (1) { /* get runlength */ token = *ip++; length = get_length(&ip, token >> ML_BITS); /* copy literals */ if (unlikely(op + length > oend - COPYLENGTH)) { /* * Error: not enough place for another match * (min 4) + 5 literals */ if (op + length != oend) goto _output_error; MEMCPY_ADVANCE(op, ip, length); break; /* EOF */ } MEMCPY_ADVANCE_CHUNKED(op, ip, length); /* get match offset */ offset = GET_LE16_ADVANCE(ip); ref = op - offset; /* Error: offset create reference outside destination buffer */ if (unlikely(ref < (u8 *const) dest)) goto _output_error; /* get match length */ length = get_length(&ip, token & ML_MASK); length += MINMATCH; /* copy first STEPSIZE bytes of match: */ if (unlikely(offset < STEPSIZE)) { MEMCPY_ADVANCE_BYTES(op, ref, 4); ref -= dec32table[offset]; memcpy(op, ref, 4); op += STEPSIZE - 4; ref -= dec64table[offset]; } else { MEMCPY_ADVANCE(op, ref, STEPSIZE); } length -= STEPSIZE; /* * Note - length could have been < STEPSIZE; that's ok, length * will now be negative and we'll just end up rewinding op: */ /* copy rest of match: */ cpy = op + length; if (cpy > oend - COPYLENGTH) { /* Error: request to write beyond destination buffer */ if (cpy > oend || ref + COPYLENGTH > oend) goto _output_error; #if !LZ4_ARCH64 if (op + COPYLENGTH > oend) goto _output_error; #endif MEMCPY_ADVANCE_CHUNKED_NOFIXUP(op, ref, oend - COPYLENGTH); /* op could be > cpy here */ 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; } else { MEMCPY_ADVANCE_CHUNKED(op, ref, length); } } /* end of decoding */ return ip - source; /* write overflow error detected */ _output_error: return -1; } static inline ssize_t get_length_safe(const u8 **ip, ssize_t length) { if (length == 15) { size_t len; do { length += (len = *(*ip)++); if (unlikely((ssize_t) length < 0)) return -1; length += len; } while (len == 255); } return length; } static int lz4_uncompress_unknownoutputsize(const u8 *source, u8 *dest, int isize, size_t maxoutputsize) { const u8 *ip = source; const u8 *const iend = ip + isize; const u8 *ref; u8 *op = dest; u8 * const oend = op + maxoutputsize; u8 *cpy; unsigned token, offset; size_t length; /* Main Loop */ while (ip < iend) { /* get runlength */ token = *ip++; length = get_length_safe(&ip, token >> ML_BITS); if (unlikely((ssize_t) length < 0)) goto _output_error; /* copy literals */ if ((op + length > oend - COPYLENGTH) || (ip + length > iend - COPYLENGTH)) { if (op + length > 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_ADVANCE(op, ip, length); break;/* Necessarily EOF, due to parsing restrictions */ } MEMCPY_ADVANCE_CHUNKED(op, ip, length); /* get match offset */ offset = GET_LE16_ADVANCE(ip); ref = op - offset; /* Error: offset create reference outside destination buffer */ if (ref < (u8 * const) dest) goto _output_error; /* get match length */ length = get_length_safe(&ip, token & ML_MASK); if (unlikely((ssize_t) length < 0)) goto _output_error; length += MINMATCH; /* copy first STEPSIZE bytes of match: */ if (unlikely(offset < STEPSIZE)) { MEMCPY_ADVANCE_BYTES(op, ref, 4); ref -= dec32table[offset]; memcpy(op, ref, 4); op += STEPSIZE - 4; ref -= dec64table[offset]; } else { MEMCPY_ADVANCE(op, ref, STEPSIZE); } length -= STEPSIZE; /* copy rest of match: */ cpy = op + length; if (cpy > oend - COPYLENGTH) { /* Error: request to write beyond destination buffer */ if (cpy > oend || ref + COPYLENGTH > oend) goto _output_error; #if !LZ4_ARCH64 if (op + COPYLENGTH > oend) goto _output_error; #endif MEMCPY_ADVANCE_CHUNKED_NOFIXUP(op, ref, 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; } else { MEMCPY_ADVANCE_CHUNKED(op, ref, length); } } /* end of decoding */ return op - dest; /* write overflow error detected */ _output_error: return -1; } 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