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Diffstat (limited to 'lib/lz4/lz4_compress.c')
| -rw-r--r-- | lib/lz4/lz4_compress.c | 443 |
1 files changed, 443 insertions, 0 deletions
diff --git a/lib/lz4/lz4_compress.c b/lib/lz4/lz4_compress.c new file mode 100644 index 0000000..fd94058 --- /dev/null +++ b/lib/lz4/lz4_compress.c @@ -0,0 +1,443 @@ +/* + * 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_GPL(lz4_compress); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("LZ4 compressor"); |
