diff options
Diffstat (limited to 'lib/lz4')
| -rw-r--r-- | lib/lz4/Makefile | 2 | ||||
| -rw-r--r-- | lib/lz4/lz4_compress.c | 443 | ||||
| -rw-r--r-- | lib/lz4/lz4defs.h | 66 | ||||
| -rw-r--r-- | lib/lz4/lz4hc_compress.c | 539 |
4 files changed, 1048 insertions, 2 deletions
diff --git a/lib/lz4/Makefile b/lib/lz4/Makefile index 7f548c6d1c5..8085d04e930 100644 --- a/lib/lz4/Makefile +++ b/lib/lz4/Makefile @@ -1 +1,3 @@ +obj-$(CONFIG_LZ4_COMPRESS) += lz4_compress.o +obj-$(CONFIG_LZ4HC_COMPRESS) += lz4hc_compress.o obj-$(CONFIG_LZ4_DECOMPRESS) += lz4_decompress.o diff --git a/lib/lz4/lz4_compress.c b/lib/lz4/lz4_compress.c new file mode 100644 index 00000000000..fd94058bd7f --- /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"); diff --git a/lib/lz4/lz4defs.h b/lib/lz4/lz4defs.h index 43ac31d63f3..abcecdc2d0f 100644 --- a/lib/lz4/lz4defs.h +++ b/lib/lz4/lz4defs.h @@ -22,23 +22,40 @@ * Architecture-specific macros */ #define BYTE u8 +typedef struct _U16_S { u16 v; } U16_S; +typedef struct _U32_S { u32 v; } U32_S; +typedef struct _U64_S { u64 v; } U64_S; #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) \ || defined(CONFIG_ARM) && __LINUX_ARM_ARCH__ >= 6 \ && defined(ARM_EFFICIENT_UNALIGNED_ACCESS) -typedef struct _U32_S { u32 v; } U32_S; -typedef struct _U64_S { u64 v; } U64_S; +#define A16(x) (((U16_S *)(x))->v) #define A32(x) (((U32_S *)(x))->v) #define A64(x) (((U64_S *)(x))->v) #define PUT4(s, d) (A32(d) = A32(s)) #define PUT8(s, d) (A64(d) = A64(s)) +#define LZ4_WRITE_LITTLEENDIAN_16(p, v) \ + do { \ + A16(p) = v; \ + p += 2; \ + } while (0) #else /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */ +#define A64(x) get_unaligned((u64 *)&(((U16_S *)(x))->v)) +#define A32(x) get_unaligned((u32 *)&(((U16_S *)(x))->v)) +#define A16(x) get_unaligned((u16 *)&(((U16_S *)(x))->v)) + #define PUT4(s, d) \ put_unaligned(get_unaligned((const u32 *) s), (u32 *) d) #define PUT8(s, d) \ put_unaligned(get_unaligned((const u64 *) s), (u64 *) d) + +#define LZ4_WRITE_LITTLEENDIAN_16(p, v) \ + do { \ + put_unaligned(v, (u16 *)(p)); \ + p += 2; \ + } while (0) #endif #define COPYLENGTH 8 @@ -46,6 +63,29 @@ typedef struct _U64_S { u64 v; } U64_S; #define ML_MASK ((1U << ML_BITS) - 1) #define RUN_BITS (8 - ML_BITS) #define RUN_MASK ((1U << RUN_BITS) - 1) +#define MEMORY_USAGE 14 +#define MINMATCH 4 +#define SKIPSTRENGTH 6 +#define LASTLITERALS 5 +#define MFLIMIT (COPYLENGTH + MINMATCH) +#define MINLENGTH (MFLIMIT + 1) +#define MAXD_LOG 16 +#define MAXD (1 << MAXD_LOG) +#define MAXD_MASK (u32)(MAXD - 1) +#define MAX_DISTANCE (MAXD - 1) +#define HASH_LOG (MAXD_LOG - 1) +#define HASHTABLESIZE (1 << HASH_LOG) +#define MAX_NB_ATTEMPTS 256 +#define OPTIMAL_ML (int)((ML_MASK-1)+MINMATCH) +#define LZ4_64KLIMIT ((1<<16) + (MFLIMIT - 1)) +#define HASHLOG64K ((MEMORY_USAGE - 2) + 1) +#define HASH64KTABLESIZE (1U << HASHLOG64K) +#define LZ4_HASH_VALUE(p) (((A32(p)) * 2654435761U) >> \ + ((MINMATCH * 8) - (MEMORY_USAGE-2))) +#define LZ4_HASH64K_VALUE(p) (((A32(p)) * 2654435761U) >> \ + ((MINMATCH * 8) - HASHLOG64K)) +#define HASH_VALUE(p) (((A32(p)) * 2654435761U) >> \ + ((MINMATCH * 8) - HASH_LOG)) #if LZ4_ARCH64/* 64-bit */ #define STEPSIZE 8 @@ -65,6 +105,13 @@ typedef struct _U64_S { u64 v; } U64_S; LZ4_WILDCOPY(s, d, e); \ } \ } while (0) +#define HTYPE u32 + +#ifdef __BIG_ENDIAN +#define LZ4_NBCOMMONBYTES(val) (__builtin_clzll(val) >> 3) +#else +#define LZ4_NBCOMMONBYTES(val) (__builtin_ctzll(val) >> 3) +#endif #else /* 32-bit */ #define STEPSIZE 4 @@ -83,6 +130,14 @@ typedef struct _U64_S { u64 v; } U64_S; } while (0) #define LZ4_SECURECOPY LZ4_WILDCOPY +#define HTYPE const u8* + +#ifdef __BIG_ENDIAN +#define LZ4_NBCOMMONBYTES(val) (__builtin_clz(val) >> 3) +#else +#define LZ4_NBCOMMONBYTES(val) (__builtin_ctz(val) >> 3) +#endif + #endif #define LZ4_READ_LITTLEENDIAN_16(d, s, p) \ @@ -92,3 +147,10 @@ typedef struct _U64_S { u64 v; } U64_S; do { \ LZ4_COPYPACKET(s, d); \ } while (d < e) + +#define LZ4_BLINDCOPY(s, d, l) \ + do { \ + u8 *e = (d) + l; \ + LZ4_WILDCOPY(s, d, e); \ + d = e; \ + } while (0) diff --git a/lib/lz4/lz4hc_compress.c b/lib/lz4/lz4hc_compress.c new file mode 100644 index 00000000000..eb1a74f5e36 --- /dev/null +++ b/lib/lz4/lz4hc_compress.c @@ -0,0 +1,539 @@ +/* + * LZ4 HC - High Compression Mode of LZ4 + * 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" + +struct lz4hc_data { + const u8 *base; + HTYPE hashtable[HASHTABLESIZE]; + u16 chaintable[MAXD]; + const u8 *nexttoupdate; +} __attribute__((__packed__)); + +static inline int lz4hc_init(struct lz4hc_data *hc4, const u8 *base) +{ + memset((void *)hc4->hashtable, 0, sizeof(hc4->hashtable)); + memset(hc4->chaintable, 0xFF, sizeof(hc4->chaintable)); + +#if LZ4_ARCH64 + hc4->nexttoupdate = base + 1; +#else + hc4->nexttoupdate = base; +#endif + hc4->base = base; + return 1; +} + +/* Update chains up to ip (excluded) */ +static inline void lz4hc_insert(struct lz4hc_data *hc4, const u8 *ip) +{ + u16 *chaintable = hc4->chaintable; + HTYPE *hashtable = hc4->hashtable; +#if LZ4_ARCH64 + const BYTE * const base = hc4->base; +#else + const int base = 0; +#endif + + while (hc4->nexttoupdate < ip) { + const u8 *p = hc4->nexttoupdate; + size_t delta = p - (hashtable[HASH_VALUE(p)] + base); + if (delta > MAX_DISTANCE) + delta = MAX_DISTANCE; + chaintable[(size_t)(p) & MAXD_MASK] = (u16)delta; + hashtable[HASH_VALUE(p)] = (p) - base; + hc4->nexttoupdate++; + } +} + +static inline size_t lz4hc_commonlength(const u8 *p1, const u8 *p2, + const u8 *const matchlimit) +{ + const u8 *p1t = p1; + + while (p1t < matchlimit - (STEPSIZE - 1)) { +#if LZ4_ARCH64 + u64 diff = A64(p2) ^ A64(p1t); +#else + u32 diff = A32(p2) ^ A32(p1t); +#endif + if (!diff) { + p1t += STEPSIZE; + p2 += STEPSIZE; + continue; + } + p1t += LZ4_NBCOMMONBYTES(diff); + return p1t - p1; + } +#if LZ4_ARCH64 + if ((p1t < (matchlimit-3)) && (A32(p2) == A32(p1t))) { + p1t += 4; + p2 += 4; + } +#endif + + if ((p1t < (matchlimit - 1)) && (A16(p2) == A16(p1t))) { + p1t += 2; + p2 += 2; + } + if ((p1t < matchlimit) && (*p2 == *p1t)) + p1t++; + return p1t - p1; +} + +static inline int lz4hc_insertandfindbestmatch(struct lz4hc_data *hc4, + const u8 *ip, const u8 *const matchlimit, const u8 **matchpos) +{ + u16 *const chaintable = hc4->chaintable; + HTYPE *const hashtable = hc4->hashtable; + const u8 *ref; +#if LZ4_ARCH64 + const BYTE * const base = hc4->base; +#else + const int base = 0; +#endif + int nbattempts = MAX_NB_ATTEMPTS; + size_t repl = 0, ml = 0; + u16 delta; + + /* HC4 match finder */ + lz4hc_insert(hc4, ip); + ref = hashtable[HASH_VALUE(ip)] + base; + + /* potential repetition */ + if (ref >= ip-4) { + /* confirmed */ + if (A32(ref) == A32(ip)) { + delta = (u16)(ip-ref); + repl = ml = lz4hc_commonlength(ip + MINMATCH, + ref + MINMATCH, matchlimit) + MINMATCH; + *matchpos = ref; + } + ref -= (size_t)chaintable[(size_t)(ref) & MAXD_MASK]; + } + + while ((ref >= ip - MAX_DISTANCE) && nbattempts) { + nbattempts--; + if (*(ref + ml) == *(ip + ml)) { + if (A32(ref) == A32(ip)) { + size_t mlt = + lz4hc_commonlength(ip + MINMATCH, + ref + MINMATCH, matchlimit) + MINMATCH; + if (mlt > ml) { + ml = mlt; + *matchpos = ref; + } + } + } + ref -= (size_t)chaintable[(size_t)(ref) & MAXD_MASK]; + } + + /* Complete table */ + if (repl) { + const BYTE *ptr = ip; + const BYTE *end; + end = ip + repl - (MINMATCH-1); + /* Pre-Load */ + while (ptr < end - delta) { + chaintable[(size_t)(ptr) & MAXD_MASK] = delta; + ptr++; + } + do { + chaintable[(size_t)(ptr) & MAXD_MASK] = delta; + /* Head of chain */ + hashtable[HASH_VALUE(ptr)] = (ptr) - base; + ptr++; + } while (ptr < end); + hc4->nexttoupdate = end; + } + + return (int)ml; +} + +static inline int lz4hc_insertandgetwidermatch(struct lz4hc_data *hc4, + const u8 *ip, const u8 *startlimit, const u8 *matchlimit, int longest, + const u8 **matchpos, const u8 **startpos) +{ + u16 *const chaintable = hc4->chaintable; + HTYPE *const hashtable = hc4->hashtable; +#if LZ4_ARCH64 + const BYTE * const base = hc4->base; +#else + const int base = 0; +#endif + const u8 *ref; + int nbattempts = MAX_NB_ATTEMPTS; + int delta = (int)(ip - startlimit); + + /* First Match */ + lz4hc_insert(hc4, ip); + ref = hashtable[HASH_VALUE(ip)] + base; + + while ((ref >= ip - MAX_DISTANCE) && (ref >= hc4->base) + && (nbattempts)) { + nbattempts--; + if (*(startlimit + longest) == *(ref - delta + longest)) { + if (A32(ref) == A32(ip)) { + const u8 *reft = ref + MINMATCH; + const u8 *ipt = ip + MINMATCH; + const u8 *startt = ip; + + while (ipt < matchlimit-(STEPSIZE - 1)) { + #if LZ4_ARCH64 + u64 diff = A64(reft) ^ A64(ipt); + #else + u32 diff = A32(reft) ^ A32(ipt); + #endif + + if (!diff) { + ipt += STEPSIZE; + reft += STEPSIZE; + continue; + } + ipt += LZ4_NBCOMMONBYTES(diff); + goto _endcount; + } + #if LZ4_ARCH64 + if ((ipt < (matchlimit - 3)) + && (A32(reft) == A32(ipt))) { + ipt += 4; + reft += 4; + } + ipt += 2; + #endif + if ((ipt < (matchlimit - 1)) + && (A16(reft) == A16(ipt))) { + reft += 2; + } + if ((ipt < matchlimit) && (*reft == *ipt)) + ipt++; +_endcount: + reft = ref; + + while ((startt > startlimit) + && (reft > hc4->base) + && (startt[-1] == reft[-1])) { + startt--; + reft--; + } + + if ((ipt - startt) > longest) { + longest = (int)(ipt - startt); + *matchpos = reft; + *startpos = startt; + } + } + } + ref -= (size_t)chaintable[(size_t)(ref) & MAXD_MASK]; + } + return longest; +} + +static inline int lz4_encodesequence(const u8 **ip, u8 **op, const u8 **anchor, + int ml, const u8 *ref) +{ + int length, len; + u8 *token; + + /* Encode Literal length */ + length = (int)(*ip - *anchor); + token = (*op)++; + 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); + + /* Encode Offset */ + LZ4_WRITE_LITTLEENDIAN_16(*op, (u16)(*ip - ref)); + + /* Encode MatchLength */ + len = (int)(ml - MINMATCH); + 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; + + /* Prepare next loop */ + *ip += ml; + *anchor = *ip; + + return 0; +} + +static int lz4_compresshcctx(struct lz4hc_data *ctx, + const char *source, + char *dest, + int isize) +{ + const u8 *ip = (const u8 *)source; + const u8 *anchor = ip; + const u8 *const iend = ip + isize; + const u8 *const mflimit = iend - MFLIMIT; + const u8 *const matchlimit = (iend - LASTLITERALS); + + u8 *op = (u8 *)dest; + + int ml, ml2, ml3, ml0; + const u8 *ref = NULL; + const u8 *start2 = NULL; + const u8 *ref2 = NULL; + const u8 *start3 = NULL; + const u8 *ref3 = NULL; + const u8 *start0; + const u8 *ref0; + int lastrun; + + ip++; + + /* Main Loop */ + while (ip < mflimit) { + ml = lz4hc_insertandfindbestmatch(ctx, ip, matchlimit, (&ref)); + if (!ml) { + ip++; + continue; + } + + /* saved, in case we would skip too much */ + start0 = ip; + ref0 = ref; + ml0 = ml; +_search2: + if (ip+ml < mflimit) + ml2 = lz4hc_insertandgetwidermatch(ctx, ip + ml - 2, + ip + 1, matchlimit, ml, &ref2, &start2); + else + ml2 = ml; + /* No better match */ + if (ml2 == ml) { + lz4_encodesequence(&ip, &op, &anchor, ml, ref); + continue; + } + + if (start0 < ip) { + /* empirical */ + if (start2 < ip + ml0) { + ip = start0; + ref = ref0; + ml = ml0; + } + } + /* + * Here, start0==ip + * First Match too small : removed + */ + if ((start2 - ip) < 3) { + ml = ml2; + ip = start2; + ref = ref2; + goto _search2; + } + +_search3: + /* + * Currently we have : + * ml2 > ml1, and + * ip1+3 <= ip2 (usually < ip1+ml1) + */ + if ((start2 - ip) < OPTIMAL_ML) { + int correction; + int new_ml = ml; + if (new_ml > OPTIMAL_ML) + new_ml = OPTIMAL_ML; + if (ip + new_ml > start2 + ml2 - MINMATCH) + new_ml = (int)(start2 - ip) + ml2 - MINMATCH; + correction = new_ml - (int)(start2 - ip); + if (correction > 0) { + start2 += correction; + ref2 += correction; + ml2 -= correction; + } + } + /* + * Now, we have start2 = ip+new_ml, + * with new_ml=min(ml, OPTIMAL_ML=18) + */ + if (start2 + ml2 < mflimit) + ml3 = lz4hc_insertandgetwidermatch(ctx, + start2 + ml2 - 3, start2, matchlimit, + ml2, &ref3, &start3); + else + ml3 = ml2; + + /* No better match : 2 sequences to encode */ + if (ml3 == ml2) { + /* ip & ref are known; Now for ml */ + if (start2 < ip+ml) + ml = (int)(start2 - ip); + + /* Now, encode 2 sequences */ + lz4_encodesequence(&ip, &op, &anchor, ml, ref); + ip = start2; + lz4_encodesequence(&ip, &op, &anchor, ml2, ref2); + continue; + } + + /* Not enough space for match 2 : remove it */ + if (start3 < ip + ml + 3) { + /* + * can write Seq1 immediately ==> Seq2 is removed, + * so Seq3 becomes Seq1 + */ + if (start3 >= (ip + ml)) { + if (start2 < ip + ml) { + int correction = + (int)(ip + ml - start2); + start2 += correction; + ref2 += correction; + ml2 -= correction; + if (ml2 < MINMATCH) { + start2 = start3; + ref2 = ref3; + ml2 = ml3; + } + } + + lz4_encodesequence(&ip, &op, &anchor, ml, ref); + ip = start3; + ref = ref3; + ml = ml3; + + start0 = start2; + ref0 = ref2; + ml0 = ml2; + goto _search2; + } + + start2 = start3; + ref2 = ref3; + ml2 = ml3; + goto _search3; + } + + /* + * OK, now we have 3 ascending matches; let's write at least + * the first one ip & ref are known; Now for ml + */ + if (start2 < ip + ml) { + if ((start2 - ip) < (int)ML_MASK) { + int correction; + if (ml > OPTIMAL_ML) + ml = OPTIMAL_ML; + if (ip + ml > start2 + ml2 - MINMATCH) + ml = (int)(start2 - ip) + ml2 + - MINMATCH; + correction = ml - (int)(start2 - ip); + if (correction > 0) { + start2 += correction; + ref2 += correction; + ml2 -= correction; + } + } else + ml = (int)(start2 - ip); + } + lz4_encodesequence(&ip, &op, &anchor, ml, ref); + + ip = start2; + ref = ref2; + ml = ml2; + + start2 = start3; + ref2 = ref3; + ml2 = ml3; + + goto _search3; + } + + /* Encode Last Literals */ + lastrun = (int)(iend - anchor); + 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 lz4hc_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; + + struct lz4hc_data *hc4 = (struct lz4hc_data *)wrkmem; + lz4hc_init(hc4, (const u8 *)src); + out_len = lz4_compresshcctx((struct lz4hc_data *)hc4, (const u8 *)src, + (char *)dst, (int)src_len); + + if (out_len < 0) + goto exit; + + *dst_len = out_len; + return 0; + +exit: + return ret; +} +EXPORT_SYMBOL_GPL(lz4hc_compress); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("LZ4HC compressor"); |