| /* |
| * 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/ |
| * |
| * Changed for kernel use by: |
| * Chanho Min <chanho.min@lge.com> |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| #include <linux/lz4.h> |
| #include <asm/unaligned.h> |
| #include "lz4defs.h" |
| |
| /* |
| * LZ4_compressCtx : |
| * ----------------- |
| * Compress 'isize' bytes from 'source' into an output buffer 'dest' of |
| * maximum size 'maxOutputSize'. * If it cannot achieve it, compression |
| * will stop, and result of the function will be zero. |
| * return : the number of bytes written in buffer 'dest', or 0 if the |
| * compression fails |
| */ |
| static inline int lz4_compressctx(void *ctx, |
| const char *source, |
| char *dest, |
| int isize, |
| int maxoutputsize) |
| { |
| HTYPE *hashtable = (HTYPE *)ctx; |
| const u8 *ip = (u8 *)source; |
| #if LZ4_ARCH64 |
| const BYTE * const base = ip; |
| #else |
| const int base = 0; |
| #endif |
| const u8 *anchor = ip; |
| const u8 *const iend = ip + isize; |
| const u8 *const mflimit = iend - MFLIMIT; |
| #define MATCHLIMIT (iend - LASTLITERALS) |
| |
| u8 *op = (u8 *) dest; |
| u8 *const oend = op + maxoutputsize; |
| int length; |
| const int skipstrength = SKIPSTRENGTH; |
| u32 forwardh; |
| int lastrun; |
| |
| /* Init */ |
| if (isize < MINLENGTH) |
| goto _last_literals; |
| |
| memset((void *)hashtable, 0, LZ4_MEM_COMPRESS); |
| |
| /* First Byte */ |
| hashtable[LZ4_HASH_VALUE(ip)] = ip - base; |
| ip++; |
| forwardh = LZ4_HASH_VALUE(ip); |
| |
| /* Main Loop */ |
| for (;;) { |
| int findmatchattempts = (1U << skipstrength) + 3; |
| const u8 *forwardip = ip; |
| const u8 *ref; |
| u8 *token; |
| |
| /* Find a match */ |
| do { |
| u32 h = forwardh; |
| int step = findmatchattempts++ >> skipstrength; |
| ip = forwardip; |
| forwardip = ip + step; |
| |
| if (unlikely(forwardip > mflimit)) |
| goto _last_literals; |
| |
| forwardh = LZ4_HASH_VALUE(forwardip); |
| ref = base + hashtable[h]; |
| hashtable[h] = ip - base; |
| } while ((ref < ip - MAX_DISTANCE) || (A32(ref) != A32(ip))); |
| |
| /* Catch up */ |
| while ((ip > anchor) && (ref > (u8 *)source) && |
| unlikely(ip[-1] == ref[-1])) { |
| ip--; |
| ref--; |
| } |
| |
| /* Encode Literal length */ |
| length = (int)(ip - anchor); |
| token = op++; |
| /* check output limit */ |
| if (unlikely(op + length + (2 + 1 + LASTLITERALS) + |
| (length >> 8) > oend)) |
| return 0; |
| |
| if (length >= (int)RUN_MASK) { |
| int len; |
| *token = (RUN_MASK << ML_BITS); |
| len = length - RUN_MASK; |
| for (; len > 254 ; len -= 255) |
| *op++ = 255; |
| *op++ = (u8)len; |
| } else |
| *token = (length << ML_BITS); |
| |
| /* Copy Literals */ |
| LZ4_BLINDCOPY(anchor, op, length); |
| _next_match: |
| /* Encode Offset */ |
| LZ4_WRITE_LITTLEENDIAN_16(op, (u16)(ip - ref)); |
| |
| /* Start Counting */ |
| ip += MINMATCH; |
| /* MinMatch verified */ |
| ref += MINMATCH; |
| anchor = ip; |
| while (likely(ip < MATCHLIMIT - (STEPSIZE - 1))) { |
| #if LZ4_ARCH64 |
| u64 diff = A64(ref) ^ A64(ip); |
| #else |
| u32 diff = A32(ref) ^ A32(ip); |
| #endif |
| if (!diff) { |
| ip += STEPSIZE; |
| ref += STEPSIZE; |
| continue; |
| } |
| ip += LZ4_NBCOMMONBYTES(diff); |
| goto _endcount; |
| } |
| #if LZ4_ARCH64 |
| if ((ip < (MATCHLIMIT - 3)) && (A32(ref) == A32(ip))) { |
| ip += 4; |
| ref += 4; |
| } |
| #endif |
| if ((ip < (MATCHLIMIT - 1)) && (A16(ref) == A16(ip))) { |
| ip += 2; |
| ref += 2; |
| } |
| if ((ip < MATCHLIMIT) && (*ref == *ip)) |
| ip++; |
| _endcount: |
| /* Encode MatchLength */ |
| length = (int)(ip - anchor); |
| /* Check output limit */ |
| if (unlikely(op + (1 + LASTLITERALS) + (length >> 8) > oend)) |
| return 0; |
| if (length >= (int)ML_MASK) { |
| *token += ML_MASK; |
| length -= ML_MASK; |
| for (; length > 509 ; length -= 510) { |
| *op++ = 255; |
| *op++ = 255; |
| } |
| if (length > 254) { |
| length -= 255; |
| *op++ = 255; |
| } |
| *op++ = (u8)length; |
| } else |
| *token += length; |
| |
| /* Test end of chunk */ |
| if (ip > mflimit) { |
| anchor = ip; |
| break; |
| } |
| |
| /* Fill table */ |
| hashtable[LZ4_HASH_VALUE(ip-2)] = ip - 2 - base; |
| |
| /* Test next position */ |
| ref = base + hashtable[LZ4_HASH_VALUE(ip)]; |
| hashtable[LZ4_HASH_VALUE(ip)] = ip - base; |
| if ((ref > ip - (MAX_DISTANCE + 1)) && (A32(ref) == A32(ip))) { |
| token = op++; |
| *token = 0; |
| goto _next_match; |
| } |
| |
| /* Prepare next loop */ |
| anchor = ip++; |
| forwardh = LZ4_HASH_VALUE(ip); |
| } |
| |
| _last_literals: |
| /* Encode Last Literals */ |
| lastrun = (int)(iend - anchor); |
| if (((char *)op - dest) + lastrun + 1 |
| + ((lastrun + 255 - RUN_MASK) / 255) > (u32)maxoutputsize) |
| return 0; |
| |
| if (lastrun >= (int)RUN_MASK) { |
| *op++ = (RUN_MASK << ML_BITS); |
| lastrun -= RUN_MASK; |
| for (; lastrun > 254 ; lastrun -= 255) |
| *op++ = 255; |
| *op++ = (u8)lastrun; |
| } else |
| *op++ = (lastrun << ML_BITS); |
| memcpy(op, anchor, iend - anchor); |
| op += iend - anchor; |
| |
| /* End */ |
| return (int)(((char *)op) - dest); |
| } |
| |
| static inline int lz4_compress64kctx(void *ctx, |
| const char *source, |
| char *dest, |
| int isize, |
| int maxoutputsize) |
| { |
| u16 *hashtable = (u16 *)ctx; |
| const u8 *ip = (u8 *) source; |
| const u8 *anchor = ip; |
| const u8 *const base = ip; |
| const u8 *const iend = ip + isize; |
| const u8 *const mflimit = iend - MFLIMIT; |
| #define MATCHLIMIT (iend - LASTLITERALS) |
| |
| u8 *op = (u8 *) dest; |
| u8 *const oend = op + maxoutputsize; |
| int len, length; |
| const int skipstrength = SKIPSTRENGTH; |
| u32 forwardh; |
| int lastrun; |
| |
| /* Init */ |
| if (isize < MINLENGTH) |
| goto _last_literals; |
| |
| memset((void *)hashtable, 0, LZ4_MEM_COMPRESS); |
| |
| /* First Byte */ |
| ip++; |
| forwardh = LZ4_HASH64K_VALUE(ip); |
| |
| /* Main Loop */ |
| for (;;) { |
| int findmatchattempts = (1U << skipstrength) + 3; |
| const u8 *forwardip = ip; |
| const u8 *ref; |
| u8 *token; |
| |
| /* Find a match */ |
| do { |
| u32 h = forwardh; |
| int step = findmatchattempts++ >> skipstrength; |
| ip = forwardip; |
| forwardip = ip + step; |
| |
| if (forwardip > mflimit) |
| goto _last_literals; |
| |
| forwardh = LZ4_HASH64K_VALUE(forwardip); |
| ref = base + hashtable[h]; |
| hashtable[h] = (u16)(ip - base); |
| } while (A32(ref) != A32(ip)); |
| |
| /* Catch up */ |
| while ((ip > anchor) && (ref > (u8 *)source) |
| && (ip[-1] == ref[-1])) { |
| ip--; |
| ref--; |
| } |
| |
| /* Encode Literal length */ |
| length = (int)(ip - anchor); |
| token = op++; |
| /* Check output limit */ |
| if (unlikely(op + length + (2 + 1 + LASTLITERALS) |
| + (length >> 8) > oend)) |
| return 0; |
| if (length >= (int)RUN_MASK) { |
| *token = (RUN_MASK << ML_BITS); |
| len = length - RUN_MASK; |
| for (; len > 254 ; len -= 255) |
| *op++ = 255; |
| *op++ = (u8)len; |
| } else |
| *token = (length << ML_BITS); |
| |
| /* Copy Literals */ |
| LZ4_BLINDCOPY(anchor, op, length); |
| |
| _next_match: |
| /* Encode Offset */ |
| LZ4_WRITE_LITTLEENDIAN_16(op, (u16)(ip - ref)); |
| |
| /* Start Counting */ |
| ip += MINMATCH; |
| /* MinMatch verified */ |
| ref += MINMATCH; |
| anchor = ip; |
| |
| while (ip < MATCHLIMIT - (STEPSIZE - 1)) { |
| #if LZ4_ARCH64 |
| u64 diff = A64(ref) ^ A64(ip); |
| #else |
| u32 diff = A32(ref) ^ A32(ip); |
| #endif |
| |
| if (!diff) { |
| ip += STEPSIZE; |
| ref += STEPSIZE; |
| continue; |
| } |
| ip += LZ4_NBCOMMONBYTES(diff); |
| goto _endcount; |
| } |
| #if LZ4_ARCH64 |
| if ((ip < (MATCHLIMIT - 3)) && (A32(ref) == A32(ip))) { |
| ip += 4; |
| ref += 4; |
| } |
| #endif |
| if ((ip < (MATCHLIMIT - 1)) && (A16(ref) == A16(ip))) { |
| ip += 2; |
| ref += 2; |
| } |
| if ((ip < MATCHLIMIT) && (*ref == *ip)) |
| ip++; |
| _endcount: |
| |
| /* Encode MatchLength */ |
| len = (int)(ip - anchor); |
| /* Check output limit */ |
| if (unlikely(op + (1 + LASTLITERALS) + (len >> 8) > oend)) |
| return 0; |
| if (len >= (int)ML_MASK) { |
| *token += ML_MASK; |
| len -= ML_MASK; |
| for (; len > 509 ; len -= 510) { |
| *op++ = 255; |
| *op++ = 255; |
| } |
| if (len > 254) { |
| len -= 255; |
| *op++ = 255; |
| } |
| *op++ = (u8)len; |
| } else |
| *token += len; |
| |
| /* Test end of chunk */ |
| if (ip > mflimit) { |
| anchor = ip; |
| break; |
| } |
| |
| /* Fill table */ |
| hashtable[LZ4_HASH64K_VALUE(ip-2)] = (u16)(ip - 2 - base); |
| |
| /* Test next position */ |
| ref = base + hashtable[LZ4_HASH64K_VALUE(ip)]; |
| hashtable[LZ4_HASH64K_VALUE(ip)] = (u16)(ip - base); |
| if (A32(ref) == A32(ip)) { |
| token = op++; |
| *token = 0; |
| goto _next_match; |
| } |
| |
| /* Prepare next loop */ |
| anchor = ip++; |
| forwardh = LZ4_HASH64K_VALUE(ip); |
| } |
| |
| _last_literals: |
| /* Encode Last Literals */ |
| lastrun = (int)(iend - anchor); |
| if (op + lastrun + 1 + (lastrun - RUN_MASK + 255) / 255 > oend) |
| return 0; |
| if (lastrun >= (int)RUN_MASK) { |
| *op++ = (RUN_MASK << ML_BITS); |
| lastrun -= RUN_MASK; |
| for (; lastrun > 254 ; lastrun -= 255) |
| *op++ = 255; |
| *op++ = (u8)lastrun; |
| } else |
| *op++ = (lastrun << ML_BITS); |
| memcpy(op, anchor, iend - anchor); |
| op += iend - anchor; |
| /* End */ |
| return (int)(((char *)op) - dest); |
| } |
| |
| int lz4_compress(const unsigned char *src, size_t src_len, |
| unsigned char *dst, size_t *dst_len, void *wrkmem) |
| { |
| int ret = -1; |
| int out_len = 0; |
| |
| if (src_len < LZ4_64KLIMIT) |
| out_len = lz4_compress64kctx(wrkmem, src, dst, src_len, |
| lz4_compressbound(src_len)); |
| else |
| out_len = lz4_compressctx(wrkmem, src, dst, src_len, |
| lz4_compressbound(src_len)); |
| |
| if (out_len < 0) |
| goto exit; |
| |
| *dst_len = out_len; |
| |
| return 0; |
| exit: |
| return ret; |
| } |
| EXPORT_SYMBOL(lz4_compress); |
| |
| MODULE_LICENSE("Dual BSD/GPL"); |
| MODULE_DESCRIPTION("LZ4 compressor"); |