[PATCH RFC 5/9] lib/lz4: switch the compressor to the vendored sources
From: Michal Wilczynski
Date: Fri Sep 25 2026 - 07:37:35 EST
Replace the forked compressor with thin entry points over the vendored
lz4.c.
LZ4_compress_default(), LZ4_compress_fast() and LZ4_compress_destSize()
keep the trailing wrkmem argument and forward to upstream's *_extState()
entry points. The rest are plain forwarders.
Compressed output is not quite bit-for-bit identical: it differs on a
small fraction of inputs by a byte or two, with no measurable change in
ratio. Both implementations decode each other's output, so nothing
already on disk changes meaning.
<linux/lz4.h> spelled out LZ4_stream_t's layout for the fork's benefit:
lz4defs.h included the public header and the fork read internal_donotuse
back out. The vendored compressor brings upstream's own definition, so
make the public type incomplete, repeating upstream's forward
declaration. Both headers then name the same type, which
lib/decompress_unlz4.c needs since it ends up including both.
LZ4_MEMORY_USAGE, LZ4_HASHLOG, LZ4_HASHTABLESIZE, LZ4_HASH_SIZE_U32,
LZ4_STREAMSIZE_U64 and LZ4_STREAMSIZE only existed to lay that structure
out, and go with it. LZ4_MEM_COMPRESS keeps its value, 16416, as a
plain number.
Callers now allocate LZ4_MEM_COMPRESS bytes instead of
sizeof(LZ4_stream_t). Every caller but zram already did; zram is
adjusted here.
Signed-off-by: Michal Wilczynski <m.wilczynski@xxxxxxxxxxx>
---
drivers/block/zram/backend_lz4.c | 6 +-
include/linux/lz4.h | 47 +-
lib/lz4/Makefile | 11 +-
lib/lz4/lz4_compress.c | 941 ++-------------------------------------
4 files changed, 68 insertions(+), 937 deletions(-)
diff --git a/drivers/block/zram/backend_lz4.c b/drivers/block/zram/backend_lz4.c
index 1e4ad31d39a63f45b3bddd3d8a467d8d7d095beb..50265e3ce256490994cb6dae32a45da376e408e0 100644
--- a/drivers/block/zram/backend_lz4.c
+++ b/drivers/block/zram/backend_lz4.c
@@ -42,7 +42,7 @@ static int lz4_setup_params(struct zcomp_params *params)
if (!params->dict || !params->dict_sz)
return 0;
- dict_stream = kzalloc_obj(*dict_stream);
+ dict_stream = kzalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
if (!dict_stream)
return -ENOMEM;
@@ -88,7 +88,7 @@ static int lz4_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
if (!zctx->dstrm)
goto error;
- zctx->cstrm = kzalloc_obj(*zctx->cstrm);
+ zctx->cstrm = kzalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
if (!zctx->cstrm)
goto error;
}
@@ -112,7 +112,7 @@ static int lz4_compress(struct zcomp_params *params, struct zcomp_ctx *ctx,
zctx->mem);
} else {
/* Cstrm needs to be reset */
- memcpy(zctx->cstrm, params->drv_data, sizeof(*zctx->cstrm));
+ memcpy(zctx->cstrm, params->drv_data, LZ4_MEM_COMPRESS);
ret = LZ4_compress_fast_continue(zctx->cstrm, req->src,
req->dst, req->src_len,
req->dst_len, params->level);
diff --git a/include/linux/lz4.h b/include/linux/lz4.h
index ad6042a718b5428792b795db7a8d4ad44c24a985..e96353a67d617a4d734cecaf3764814df692428b 100644
--- a/include/linux/lz4.h
+++ b/include/linux/lz4.h
@@ -47,16 +47,6 @@
/*-************************************************************************
* CONSTANTS
**************************************************************************/
-/*
- * LZ4_MEMORY_USAGE :
- * Memory usage formula : N->2^N Bytes
- * (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
- * Increasing memory usage improves compression ratio
- * Reduced memory usage can improve speed, due to cache effect
- * Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache
- */
-#define LZ4_MEMORY_USAGE 14
-
#define LZ4_MAX_INPUT_SIZE 0x7E000000 /* 2 113 929 216 bytes */
#define LZ4_COMPRESSBOUND(isize) (\
(unsigned int)(isize) > (unsigned int)LZ4_MAX_INPUT_SIZE \
@@ -64,9 +54,6 @@
: (isize) + ((isize)/255) + 16)
#define LZ4_ACCELERATION_DEFAULT 1
-#define LZ4_HASHLOG (LZ4_MEMORY_USAGE-2)
-#define LZ4_HASHTABLESIZE (1 << LZ4_MEMORY_USAGE)
-#define LZ4_HASH_SIZE_U32 (1 << LZ4_HASHLOG)
#define LZ4HC_MIN_CLEVEL 3
#define LZ4HC_DEFAULT_CLEVEL 9
@@ -82,9 +69,6 @@
/*-************************************************************************
* STREAMING CONSTANTS AND STRUCTURES
**************************************************************************/
-#define LZ4_STREAMSIZE_U64 ((1 << (LZ4_MEMORY_USAGE - 3)) + 4)
-#define LZ4_STREAMSIZE (LZ4_STREAMSIZE_U64 * sizeof(unsigned long long))
-
#define LZ4_STREAMHCSIZE 262192
#define LZ4_STREAMHCSIZE_SIZET (262192 / sizeof(size_t))
@@ -93,20 +77,10 @@
sizeof(unsigned long long))
/*
- * LZ4_stream_t - information structure to track an LZ4 stream.
+ * LZ4_stream_t - an LZ4 stream. Incomplete: lib/lz4 owns the layout.
+ * Allocate LZ4_MEM_COMPRESS bytes and cast, do not sizeof().
*/
-typedef struct {
- uint32_t hashTable[LZ4_HASH_SIZE_U32];
- uint32_t currentOffset;
- uint32_t initCheck;
- const uint8_t *dictionary;
- uint8_t *bufferStart;
- uint32_t dictSize;
-} LZ4_stream_t_internal;
-typedef union {
- unsigned long long table[LZ4_STREAMSIZE_U64];
- LZ4_stream_t_internal internal_donotuse;
-} LZ4_stream_t;
+typedef union LZ4_stream_u LZ4_stream_t;
/*
* LZ4_streamHC_t - information structure to track an LZ4HC stream.
@@ -153,7 +127,12 @@ typedef union {
/*-************************************************************************
* SIZE OF STATE
**************************************************************************/
-#define LZ4_MEM_COMPRESS LZ4_STREAMSIZE
+/*
+ * Working memory for the compressors. It must be aligned to at least 8
+ * bytes; anything from kmalloc() or vmalloc() already is. A misaligned
+ * buffer is rejected, and the stateless entry points cannot report that.
+ */
+#define LZ4_MEM_COMPRESS 16416
#define LZ4HC_MEM_COMPRESS LZ4_STREAMHCSIZE
/*-************************************************************************
@@ -180,7 +159,7 @@ static inline int LZ4_compressBound(size_t isize)
* @maxOutputSize: full or partial size of buffer 'dest'
* which must be already allocated
* @wrkmem: address of the working memory.
- * This requires 'workmem' of LZ4_MEM_COMPRESS.
+ * This requires 'workmem' of LZ4_MEM_COMPRESS, aligned to 8 bytes.
*
* Compresses 'sourceSize' bytes from buffer 'source'
* into already allocated 'dest' buffer of size 'maxOutputSize'.
@@ -206,7 +185,7 @@ int LZ4_compress_default(const char *source, char *dest, int inputSize,
* which must be already allocated
* @acceleration: acceleration factor
* @wrkmem: address of the working memory.
- * This requires 'workmem' of LZ4_MEM_COMPRESS.
+ * This requires 'workmem' of LZ4_MEM_COMPRESS, aligned to 8 bytes.
*
* Same as LZ4_compress_default(), but allows to select an "acceleration"
* factor. The larger the acceleration value, the faster the algorithm,
@@ -230,7 +209,7 @@ int LZ4_compress_fast(const char *source, char *dest, int inputSize,
* from 'source' to fill 'dest'. New value is necessarily <= old value.
* @targetDestSize: Size of buffer 'dest' which must be already allocated
* @wrkmem: address of the working memory.
- * This requires 'workmem' of LZ4_MEM_COMPRESS.
+ * This requires 'workmem' of LZ4_MEM_COMPRESS, aligned to 8 bytes.
*
* Reverse the logic, by compressing as much data as possible
* from 'source' buffer into already allocated buffer 'dest'
@@ -335,7 +314,7 @@ int LZ4_decompress_safe_partial(const char *source, char *dest,
* value between 1 and LZ4HC_MAX_CLEVEL will work.
* Values >LZ4HC_MAX_CLEVEL behave the same as 16.
* @wrkmem: address of the working memory.
- * This requires 'wrkmem' of size LZ4HC_MEM_COMPRESS.
+ * This requires 'wrkmem' of size LZ4HC_MEM_COMPRESS, aligned to 8 bytes.
*
* Compress data from 'src' into 'dst', using the more powerful
* but slower "HC" algorithm. Compression is guaranteed to succeed if
diff --git a/lib/lz4/Makefile b/lib/lz4/Makefile
index 5b42242afaa20deb165d8a2f0b1c0c842dfcdc39..e9d83cff4ea4efe1097f54caba72e268cecb04af 100644
--- a/lib/lz4/Makefile
+++ b/lib/lz4/Makefile
@@ -1,6 +1,11 @@
# SPDX-License-Identifier: GPL-2.0-only
ccflags-y += -O3
-obj-$(CONFIG_LZ4_COMPRESS) += lz4_compress.o
-obj-$(CONFIG_LZ4HC_COMPRESS) += lz4hc_compress.o
-obj-$(CONFIG_LZ4_DECOMPRESS) += lz4_decompress.o
+# upstream/ holds verbatim copies of the upstream LZ4 sources; do not edit
+# them. The three entry point files include them. freestanding/ supplies
+# the ISO C headers upstream includes that -nostdinc does not provide.
+ccflags-y += -I $(src)/freestanding
+
+obj-$(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
index 2a397bb2c661d9c2e4a7a67d5f50f06bfd42f1f2..19b877fc96d1dde6fd5ff832f79beca42d5b783b 100644
--- a/lib/lz4/lz4_compress.c
+++ b/lib/lz4/lz4_compress.c
@@ -1,937 +1,84 @@
+// SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
/*
- * LZ4 - Fast LZ compression algorithm
* Copyright (C) 2011 - 2016, 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://www.lz4.org
- * - LZ4 source repository : https://github.com/lz4/lz4
+ * Copyright (C) 2016, Sven Schmidt <4sschmid@xxxxxxxxxxxxxxxxxxxxxxxxx>
+ * Copyright (c) 2026 Samsung Electronics Co., Ltd.
+ * Author: Michal Wilczynski <m.wilczynski@xxxxxxxxxxx>
*
- * Changed for kernel usage by:
- * Sven Schmidt <4sschmid@xxxxxxxxxxxxxxxxxxxxxxxxx>
- */
-
-/*-************************************
- * Dependencies
- **************************************/
-#include "lz4defs.h"
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/unaligned.h>
-
-static const int LZ4_minLength = (MFLIMIT + 1);
-static const int LZ4_64Klimit = ((64 * KB) + (MFLIMIT - 1));
-
-/*-******************************
- * Compression functions
- ********************************/
-static FORCE_INLINE U32 LZ4_hash4(
- U32 sequence,
- tableType_t const tableType)
-{
- if (tableType == byU16)
- return ((sequence * 2654435761U)
- >> ((MINMATCH * 8) - (LZ4_HASHLOG + 1)));
- else
- return ((sequence * 2654435761U)
- >> ((MINMATCH * 8) - LZ4_HASHLOG));
-}
-
-static FORCE_INLINE U32 LZ4_hash5(
- U64 sequence,
- tableType_t const tableType)
-{
- const U32 hashLog = (tableType == byU16)
- ? LZ4_HASHLOG + 1
- : LZ4_HASHLOG;
-
-#if LZ4_LITTLE_ENDIAN
- static const U64 prime5bytes = 889523592379ULL;
-
- return (U32)(((sequence << 24) * prime5bytes) >> (64 - hashLog));
-#else
- static const U64 prime8bytes = 11400714785074694791ULL;
-
- return (U32)(((sequence >> 24) * prime8bytes) >> (64 - hashLog));
-#endif
-}
-
-static FORCE_INLINE U32 LZ4_hashPosition(
- const void *p,
- tableType_t const tableType)
-{
-#if LZ4_ARCH64
- if (tableType == byU32)
- return LZ4_hash5(LZ4_read_ARCH(p), tableType);
-#endif
-
- return LZ4_hash4(LZ4_read32(p), tableType);
-}
-
-static void LZ4_putPositionOnHash(
- const BYTE *p,
- U32 h,
- void *tableBase,
- tableType_t const tableType,
- const BYTE *srcBase)
-{
- switch (tableType) {
- case byPtr:
- {
- const BYTE **hashTable = (const BYTE **)tableBase;
-
- hashTable[h] = p;
- return;
- }
- case byU32:
- {
- U32 *hashTable = (U32 *) tableBase;
-
- hashTable[h] = (U32)(p - srcBase);
- return;
- }
- case byU16:
- {
- U16 *hashTable = (U16 *) tableBase;
-
- hashTable[h] = (U16)(p - srcBase);
- return;
- }
- }
-}
-
-static FORCE_INLINE void LZ4_putPosition(
- const BYTE *p,
- void *tableBase,
- tableType_t tableType,
- const BYTE *srcBase)
-{
- U32 const h = LZ4_hashPosition(p, tableType);
-
- LZ4_putPositionOnHash(p, h, tableBase, tableType, srcBase);
-}
-
-static const BYTE *LZ4_getPositionOnHash(
- U32 h,
- void *tableBase,
- tableType_t tableType,
- const BYTE *srcBase)
-{
- if (tableType == byPtr) {
- const BYTE **hashTable = (const BYTE **) tableBase;
-
- return hashTable[h];
- }
-
- if (tableType == byU32) {
- const U32 * const hashTable = (U32 *) tableBase;
-
- return hashTable[h] + srcBase;
- }
-
- {
- /* default, to ensure a return */
- const U16 * const hashTable = (U16 *) tableBase;
-
- return hashTable[h] + srcBase;
- }
-}
-
-static FORCE_INLINE const BYTE *LZ4_getPosition(
- const BYTE *p,
- void *tableBase,
- tableType_t tableType,
- const BYTE *srcBase)
-{
- U32 const h = LZ4_hashPosition(p, tableType);
-
- return LZ4_getPositionOnHash(h, tableBase, tableType, srcBase);
-}
-
-
-/*
- * LZ4_compress_generic() :
- * inlined, to ensure branches are decided at compilation time
+ * LZ4 compressor -- kernel entry points
+ *
+ * The compressor is upstream's, in the verbatim lz4.c included below. The
+ * kernel has no heap at these call sites, so LZ4_compress_default(),
+ * LZ4_compress_fast() and LZ4_compress_destSize() take a trailing wrkmem
+ * argument and forward to upstream's *_extState() entry points.
*/
-static FORCE_INLINE int LZ4_compress_generic(
- LZ4_stream_t_internal * const dictPtr,
- const char * const source,
- char * const dest,
- const int inputSize,
- const int maxOutputSize,
- const limitedOutput_directive outputLimited,
- const tableType_t tableType,
- const dict_directive dict,
- const dictIssue_directive dictIssue,
- const U32 acceleration)
-{
- const BYTE *ip = (const BYTE *) source;
- const BYTE *base;
- const BYTE *lowLimit;
- const BYTE * const lowRefLimit = ip - dictPtr->dictSize;
- const BYTE * const dictionary = dictPtr->dictionary;
- const BYTE * const dictEnd = dictionary + dictPtr->dictSize;
- const size_t dictDelta = dictEnd - (const BYTE *)source;
- const BYTE *anchor = (const BYTE *) source;
- const BYTE * const iend = ip + inputSize;
- const BYTE * const mflimit = iend - MFLIMIT;
- const BYTE * const matchlimit = iend - LASTLITERALS;
-
- BYTE *op = (BYTE *) dest;
- BYTE * const olimit = op + maxOutputSize;
-
- U32 forwardH;
- size_t refDelta = 0;
-
- /* Init conditions */
- if ((U32)inputSize > (U32)LZ4_MAX_INPUT_SIZE) {
- /* Unsupported inputSize, too large (or negative) */
- return 0;
- }
-
- switch (dict) {
- case noDict:
- default:
- base = (const BYTE *)source;
- lowLimit = (const BYTE *)source;
- break;
- case withPrefix64k:
- base = (const BYTE *)source - dictPtr->currentOffset;
- lowLimit = (const BYTE *)source - dictPtr->dictSize;
- break;
- case usingExtDict:
- base = (const BYTE *)source - dictPtr->currentOffset;
- lowLimit = (const BYTE *)source;
- break;
- }
-
- if ((tableType == byU16)
- && (inputSize >= LZ4_64Klimit)) {
- /* Size too large (not within 64K limit) */
- return 0;
- }
-
- if (inputSize < LZ4_minLength) {
- /* Input too small, no compression (all literals) */
- goto _last_literals;
- }
-
- /* First Byte */
- LZ4_putPosition(ip, dictPtr->hashTable, tableType, base);
- ip++;
- forwardH = LZ4_hashPosition(ip, tableType);
-
- /* Main Loop */
- for ( ; ; ) {
- const BYTE *match;
- BYTE *token;
-
- /* Find a match */
- {
- const BYTE *forwardIp = ip;
- unsigned int step = 1;
- unsigned int searchMatchNb = acceleration << LZ4_SKIPTRIGGER;
-
- do {
- U32 const h = forwardH;
-
- ip = forwardIp;
- forwardIp += step;
- step = (searchMatchNb++ >> LZ4_SKIPTRIGGER);
-
- if (unlikely(forwardIp > mflimit))
- goto _last_literals;
-
- match = LZ4_getPositionOnHash(h,
- dictPtr->hashTable,
- tableType, base);
-
- if (dict == usingExtDict) {
- if (match < (const BYTE *)source) {
- refDelta = dictDelta;
- lowLimit = dictionary;
- } else {
- refDelta = 0;
- lowLimit = (const BYTE *)source;
- } }
-
- forwardH = LZ4_hashPosition(forwardIp,
- tableType);
-
- LZ4_putPositionOnHash(ip, h, dictPtr->hashTable,
- tableType, base);
- } while (((dictIssue == dictSmall)
- ? (match < lowRefLimit)
- : 0)
- || ((tableType == byU16)
- ? 0
- : (match + MAX_DISTANCE < ip))
- || (LZ4_read32(match + refDelta)
- != LZ4_read32(ip)));
- }
-
- /* Catch up */
- while (((ip > anchor) & (match + refDelta > lowLimit))
- && (unlikely(ip[-1] == match[refDelta - 1]))) {
- ip--;
- match--;
- }
-
- /* Encode Literals */
- {
- unsigned const int litLength = (unsigned int)(ip - anchor);
-
- token = op++;
-
- if ((outputLimited) &&
- /* Check output buffer overflow */
- (unlikely(op + litLength +
- (2 + 1 + LASTLITERALS) +
- (litLength / 255) > olimit)))
- return 0;
-
- if (litLength >= RUN_MASK) {
- int len = (int)litLength - RUN_MASK;
-
- *token = (RUN_MASK << ML_BITS);
-
- for (; len >= 255; len -= 255)
- *op++ = 255;
- *op++ = (BYTE)len;
- } else
- *token = (BYTE)(litLength << ML_BITS);
-
- /* Copy Literals */
- LZ4_wildCopy(op, anchor, op + litLength);
- op += litLength;
- }
-
-_next_match:
- /* Encode Offset */
- LZ4_writeLE16(op, (U16)(ip - match));
- op += 2;
-
- /* Encode MatchLength */
- {
- unsigned int matchCode;
-
- if ((dict == usingExtDict)
- && (lowLimit == dictionary)) {
- const BYTE *limit;
-
- match += refDelta;
- limit = ip + (dictEnd - match);
-
- if (limit > matchlimit)
- limit = matchlimit;
-
- matchCode = LZ4_count(ip + MINMATCH,
- match + MINMATCH, limit);
-
- ip += MINMATCH + matchCode;
-
- if (ip == limit) {
- unsigned const int more = LZ4_count(ip,
- (const BYTE *)source,
- matchlimit);
-
- matchCode += more;
- ip += more;
- }
- } else {
- matchCode = LZ4_count(ip + MINMATCH,
- match + MINMATCH, matchlimit);
- ip += MINMATCH + matchCode;
- }
-
- if (outputLimited &&
- /* Check output buffer overflow */
- (unlikely(op +
- (1 + LASTLITERALS) +
- (matchCode >> 8) > olimit)))
- return 0;
-
- if (matchCode >= ML_MASK) {
- *token += ML_MASK;
- matchCode -= ML_MASK;
- LZ4_write32(op, 0xFFFFFFFF);
-
- while (matchCode >= 4 * 255) {
- op += 4;
- LZ4_write32(op, 0xFFFFFFFF);
- matchCode -= 4 * 255;
- }
-
- op += matchCode / 255;
- *op++ = (BYTE)(matchCode % 255);
- } else
- *token += (BYTE)(matchCode);
- }
- anchor = ip;
+#include "lz4_deps.h"
+#include "upstream/lz4.c"
- /* Test end of chunk */
- if (ip > mflimit)
- break;
+/* Upstream's short names for these clash with <linux/minmax.h>. */
+#undef MIN
+#undef MAX
+#undef KB
+#undef MB
+#undef GB
- /* Fill table */
- LZ4_putPosition(ip - 2, dictPtr->hashTable, tableType, base);
-
- /* Test next position */
- match = LZ4_getPosition(ip, dictPtr->hashTable,
- tableType, base);
-
- if (dict == usingExtDict) {
- if (match < (const BYTE *)source) {
- refDelta = dictDelta;
- lowLimit = dictionary;
- } else {
- refDelta = 0;
- lowLimit = (const BYTE *)source;
- }
- }
-
- LZ4_putPosition(ip, dictPtr->hashTable, tableType, base);
-
- if (((dictIssue == dictSmall) ? (match >= lowRefLimit) : 1)
- && (match + MAX_DISTANCE >= ip)
- && (LZ4_read32(match + refDelta) == LZ4_read32(ip))) {
- token = op++;
- *token = 0;
- goto _next_match;
- }
-
- /* Prepare next loop */
- forwardH = LZ4_hashPosition(++ip, tableType);
- }
-
-_last_literals:
- /* Encode Last Literals */
- {
- size_t const lastRun = (size_t)(iend - anchor);
-
- if ((outputLimited) &&
- /* Check output buffer overflow */
- ((op - (BYTE *)dest) + lastRun + 1 +
- ((lastRun + 255 - RUN_MASK) / 255) > (U32)maxOutputSize))
- return 0;
-
- if (lastRun >= RUN_MASK) {
- size_t accumulator = lastRun - RUN_MASK;
- *op++ = RUN_MASK << ML_BITS;
- for (; accumulator >= 255; accumulator -= 255)
- *op++ = 255;
- *op++ = (BYTE) accumulator;
- } else {
- *op++ = (BYTE)(lastRun << ML_BITS);
- }
-
- LZ4_memcpy(op, anchor, lastRun);
-
- op += lastRun;
- }
-
- /* End */
- return (int) (((char *)op) - dest);
-}
-
-static int LZ4_compress_fast_extState(
- void *state,
- const char *source,
- char *dest,
- int inputSize,
- int maxOutputSize,
- int acceleration)
-{
- LZ4_stream_t_internal *ctx = &((LZ4_stream_t *)state)->internal_donotuse;
-#if LZ4_ARCH64
- const tableType_t tableType = byU32;
-#else
- const tableType_t tableType = byPtr;
-#endif
-
- LZ4_resetStream((LZ4_stream_t *)state);
-
- if (acceleration < 1)
- acceleration = LZ4_ACCELERATION_DEFAULT;
+#include "lz4_kernel_api.h"
+#include <linux/export.h>
+#include <linux/module.h>
- if (maxOutputSize >= LZ4_COMPRESSBOUND(inputSize)) {
- if (inputSize < LZ4_64Klimit)
- return LZ4_compress_generic(ctx, source,
- dest, inputSize, 0,
- noLimit, byU16, noDict,
- noDictIssue, acceleration);
- else
- return LZ4_compress_generic(ctx, source,
- dest, inputSize, 0,
- noLimit, tableType, noDict,
- noDictIssue, acceleration);
- } else {
- if (inputSize < LZ4_64Klimit)
- return LZ4_compress_generic(ctx, source,
- dest, inputSize,
- maxOutputSize, limitedOutput, byU16, noDict,
- noDictIssue, acceleration);
- else
- return LZ4_compress_generic(ctx, source,
- dest, inputSize,
- maxOutputSize, limitedOutput, tableType, noDict,
- noDictIssue, acceleration);
- }
-}
+/* Catch any divergence from upstream's layout at build time. */
+static_assert(sizeof(LZ4_stream_t) == LZ4_STREAM_MINSIZE);
+static_assert(LZ4_STREAM_MINSIZE == 16416); /* LZ4_MEM_COMPRESS */
int LZ4_compress_fast(const char *source, char *dest, int inputSize,
- int maxOutputSize, int acceleration, void *wrkmem)
+ int maxOutputSize, int acceleration, void *wrkmem)
{
return LZ4_compress_fast_extState(wrkmem, source, dest, inputSize,
- maxOutputSize, acceleration);
+ maxOutputSize, acceleration);
}
EXPORT_SYMBOL(LZ4_compress_fast);
int LZ4_compress_default(const char *source, char *dest, int inputSize,
- int maxOutputSize, void *wrkmem)
+ int maxOutputSize, void *wrkmem)
{
- return LZ4_compress_fast(source, dest, inputSize,
- maxOutputSize, LZ4_ACCELERATION_DEFAULT, wrkmem);
+ return LZ4_compress_fast(source, dest, inputSize, maxOutputSize,
+ LZ4_ACCELERATION_DEFAULT, wrkmem);
}
EXPORT_SYMBOL(LZ4_compress_default);
-/*-******************************
- * *_destSize() variant
- ********************************/
-static int LZ4_compress_destSize_generic(
- LZ4_stream_t_internal * const ctx,
- const char * const src,
- char * const dst,
- int * const srcSizePtr,
- const int targetDstSize,
- const tableType_t tableType)
+int LZ4_compress_destSize(const char *source, char *dest, int *sourceSizePtr,
+ int targetDestSize, void *wrkmem)
{
- const BYTE *ip = (const BYTE *) src;
- const BYTE *base = (const BYTE *) src;
- const BYTE *lowLimit = (const BYTE *) src;
- const BYTE *anchor = ip;
- const BYTE * const iend = ip + *srcSizePtr;
- const BYTE * const mflimit = iend - MFLIMIT;
- const BYTE * const matchlimit = iend - LASTLITERALS;
-
- BYTE *op = (BYTE *) dst;
- BYTE * const oend = op + targetDstSize;
- BYTE * const oMaxLit = op + targetDstSize - 2 /* offset */
- - 8 /* because 8 + MINMATCH == MFLIMIT */ - 1 /* token */;
- BYTE * const oMaxMatch = op + targetDstSize
- - (LASTLITERALS + 1 /* token */);
- BYTE * const oMaxSeq = oMaxLit - 1 /* token */;
-
- U32 forwardH;
-
- /* Init conditions */
- /* Impossible to store anything */
- if (targetDstSize < 1)
- return 0;
- /* Unsupported input size, too large (or negative) */
- if ((U32)*srcSizePtr > (U32)LZ4_MAX_INPUT_SIZE)
- return 0;
- /* Size too large (not within 64K limit) */
- if ((tableType == byU16) && (*srcSizePtr >= LZ4_64Klimit))
- return 0;
- /* Input too small, no compression (all literals) */
- if (*srcSizePtr < LZ4_minLength)
- goto _last_literals;
-
- /* First Byte */
- *srcSizePtr = 0;
- LZ4_putPosition(ip, ctx->hashTable, tableType, base);
- ip++; forwardH = LZ4_hashPosition(ip, tableType);
-
- /* Main Loop */
- for ( ; ; ) {
- const BYTE *match;
- BYTE *token;
-
- /* Find a match */
- {
- const BYTE *forwardIp = ip;
- unsigned int step = 1;
- unsigned int searchMatchNb = 1 << LZ4_SKIPTRIGGER;
-
- do {
- U32 h = forwardH;
-
- ip = forwardIp;
- forwardIp += step;
- step = (searchMatchNb++ >> LZ4_SKIPTRIGGER);
-
- if (unlikely(forwardIp > mflimit))
- goto _last_literals;
-
- match = LZ4_getPositionOnHash(h, ctx->hashTable,
- tableType, base);
- forwardH = LZ4_hashPosition(forwardIp,
- tableType);
- LZ4_putPositionOnHash(ip, h,
- ctx->hashTable, tableType,
- base);
-
- } while (((tableType == byU16)
- ? 0
- : (match + MAX_DISTANCE < ip))
- || (LZ4_read32(match) != LZ4_read32(ip)));
- }
-
- /* Catch up */
- while ((ip > anchor)
- && (match > lowLimit)
- && (unlikely(ip[-1] == match[-1]))) {
- ip--;
- match--;
- }
-
- /* Encode Literal length */
- {
- unsigned int litLength = (unsigned int)(ip - anchor);
-
- token = op++;
- if (op + ((litLength + 240) / 255)
- + litLength > oMaxLit) {
- /* Not enough space for a last match */
- op--;
- goto _last_literals;
- }
- if (litLength >= RUN_MASK) {
- unsigned int len = litLength - RUN_MASK;
- *token = (RUN_MASK<<ML_BITS);
- for (; len >= 255; len -= 255)
- *op++ = 255;
- *op++ = (BYTE)len;
- } else
- *token = (BYTE)(litLength << ML_BITS);
-
- /* Copy Literals */
- LZ4_wildCopy(op, anchor, op + litLength);
- op += litLength;
- }
-
-_next_match:
- /* Encode Offset */
- LZ4_writeLE16(op, (U16)(ip - match)); op += 2;
-
- /* Encode MatchLength */
- {
- size_t matchLength = LZ4_count(ip + MINMATCH,
- match + MINMATCH, matchlimit);
-
- if (op + ((matchLength + 240)/255) > oMaxMatch) {
- /* Match description too long : reduce it */
- matchLength = (15 - 1) + (oMaxMatch - op) * 255;
- }
- ip += MINMATCH + matchLength;
-
- if (matchLength >= ML_MASK) {
- *token += ML_MASK;
- matchLength -= ML_MASK;
- while (matchLength >= 255) {
- matchLength -= 255;
- *op++ = 255;
- }
- *op++ = (BYTE)matchLength;
- } else
- *token += (BYTE)(matchLength);
- }
-
- anchor = ip;
-
- /* Test end of block */
- if (ip > mflimit)
- break;
- if (op > oMaxSeq)
- break;
-
- /* Fill table */
- LZ4_putPosition(ip - 2, ctx->hashTable, tableType, base);
-
- /* Test next position */
- match = LZ4_getPosition(ip, ctx->hashTable, tableType, base);
- LZ4_putPosition(ip, ctx->hashTable, tableType, base);
-
- if ((match + MAX_DISTANCE >= ip)
- && (LZ4_read32(match) == LZ4_read32(ip))) {
- token = op++; *token = 0;
- goto _next_match;
- }
-
- /* Prepare next loop */
- forwardH = LZ4_hashPosition(++ip, tableType);
- }
-
-_last_literals:
- /* Encode Last Literals */
- {
- size_t lastRunSize = (size_t)(iend - anchor);
-
- if (op + 1 /* token */
- + ((lastRunSize + 240) / 255) /* litLength */
- + lastRunSize /* literals */ > oend) {
- /* adapt lastRunSize to fill 'dst' */
- lastRunSize = (oend - op) - 1;
- lastRunSize -= (lastRunSize + 240) / 255;
- }
- ip = anchor + lastRunSize;
-
- if (lastRunSize >= RUN_MASK) {
- size_t accumulator = lastRunSize - RUN_MASK;
-
- *op++ = RUN_MASK << ML_BITS;
- for (; accumulator >= 255; accumulator -= 255)
- *op++ = 255;
- *op++ = (BYTE) accumulator;
- } else {
- *op++ = (BYTE)(lastRunSize<<ML_BITS);
- }
- LZ4_memcpy(op, anchor, lastRunSize);
- op += lastRunSize;
- }
-
- /* End */
- *srcSizePtr = (int) (((const char *)ip) - src);
- return (int) (((char *)op) - dst);
-}
-
-static int LZ4_compress_destSize_extState(
- LZ4_stream_t *state,
- const char *src,
- char *dst,
- int *srcSizePtr,
- int targetDstSize)
-{
-#if LZ4_ARCH64
- const tableType_t tableType = byU32;
-#else
- const tableType_t tableType = byPtr;
-#endif
-
- LZ4_resetStream(state);
-
- if (targetDstSize >= LZ4_COMPRESSBOUND(*srcSizePtr)) {
- /* compression success is guaranteed */
- return LZ4_compress_fast_extState(
- state, src, dst, *srcSizePtr,
- targetDstSize, 1);
- } else {
- if (*srcSizePtr < LZ4_64Klimit)
- return LZ4_compress_destSize_generic(
- &state->internal_donotuse,
- src, dst, srcSizePtr,
- targetDstSize, byU16);
- else
- return LZ4_compress_destSize_generic(
- &state->internal_donotuse,
- src, dst, srcSizePtr,
- targetDstSize, tableType);
- }
-}
-
-
-int LZ4_compress_destSize(
- const char *src,
- char *dst,
- int *srcSizePtr,
- int targetDstSize,
- void *wrkmem)
-{
- return LZ4_compress_destSize_extState(wrkmem, src, dst, srcSizePtr,
- targetDstSize);
+ return LZ4_compress_destSize_extState(wrkmem, source, dest,
+ sourceSizePtr, targetDestSize,
+ LZ4_ACCELERATION_DEFAULT);
}
EXPORT_SYMBOL(LZ4_compress_destSize);
-/*-******************************
- * Streaming functions
- ********************************/
void LZ4_resetStream(LZ4_stream_t *LZ4_stream)
{
- memset(LZ4_stream, 0, sizeof(LZ4_stream_t));
+ __lz4_resetStream(LZ4_stream);
}
-int LZ4_loadDict(LZ4_stream_t *LZ4_dict,
- const char *dictionary, int dictSize)
+int LZ4_loadDict(LZ4_stream_t *streamPtr, const char *dictionary, int dictSize)
{
- LZ4_stream_t_internal *dict = &LZ4_dict->internal_donotuse;
- const BYTE *p = (const BYTE *)dictionary;
- const BYTE * const dictEnd = p + dictSize;
- const BYTE *base;
-
- if ((dict->initCheck)
- || (dict->currentOffset > 1 * GB)) {
- /* Uninitialized structure, or reuse overflow */
- LZ4_resetStream(LZ4_dict);
- }
-
- if (dictSize < (int)HASH_UNIT) {
- dict->dictionary = NULL;
- dict->dictSize = 0;
- return 0;
- }
-
- if ((dictEnd - p) > 64 * KB)
- p = dictEnd - 64 * KB;
- dict->currentOffset += 64 * KB;
- base = p - dict->currentOffset;
- dict->dictionary = p;
- dict->dictSize = (U32)(dictEnd - p);
- dict->currentOffset += dict->dictSize;
-
- while (p <= dictEnd - HASH_UNIT) {
- LZ4_putPosition(p, dict->hashTable, byU32, base);
- p += 3;
- }
-
- return dict->dictSize;
+ return __lz4_loadDict(streamPtr, dictionary, dictSize);
}
EXPORT_SYMBOL(LZ4_loadDict);
-static void LZ4_renormDictT(LZ4_stream_t_internal *LZ4_dict,
- const BYTE *src)
-{
- if ((LZ4_dict->currentOffset > 0x80000000) ||
- ((uptrval)LZ4_dict->currentOffset > (uptrval)src)) {
- /* address space overflow */
- /* rescale hash table */
- U32 const delta = LZ4_dict->currentOffset - 64 * KB;
- const BYTE *dictEnd = LZ4_dict->dictionary + LZ4_dict->dictSize;
- int i;
-
- for (i = 0; i < LZ4_HASH_SIZE_U32; i++) {
- if (LZ4_dict->hashTable[i] < delta)
- LZ4_dict->hashTable[i] = 0;
- else
- LZ4_dict->hashTable[i] -= delta;
- }
- LZ4_dict->currentOffset = 64 * KB;
- if (LZ4_dict->dictSize > 64 * KB)
- LZ4_dict->dictSize = 64 * KB;
- LZ4_dict->dictionary = dictEnd - LZ4_dict->dictSize;
- }
-}
-
-int LZ4_saveDict(LZ4_stream_t *LZ4_dict, char *safeBuffer, int dictSize)
+int LZ4_saveDict(LZ4_stream_t *streamPtr, char *safeBuffer, int dictSize)
{
- LZ4_stream_t_internal * const dict = &LZ4_dict->internal_donotuse;
- const BYTE * const previousDictEnd = dict->dictionary + dict->dictSize;
-
- if ((U32)dictSize > 64 * KB) {
- /* useless to define a dictionary > 64 * KB */
- dictSize = 64 * KB;
- }
- if ((U32)dictSize > dict->dictSize)
- dictSize = dict->dictSize;
-
- memmove(safeBuffer, previousDictEnd - dictSize, dictSize);
-
- dict->dictionary = (const BYTE *)safeBuffer;
- dict->dictSize = (U32)dictSize;
-
- return dictSize;
+ return __lz4_saveDict(streamPtr, safeBuffer, dictSize);
}
EXPORT_SYMBOL(LZ4_saveDict);
-int LZ4_compress_fast_continue(LZ4_stream_t *LZ4_stream, const char *source,
- char *dest, int inputSize, int maxOutputSize, int acceleration)
+int LZ4_compress_fast_continue(LZ4_stream_t *streamPtr, const char *src,
+ char *dst, int srcSize, int maxDstSize,
+ int acceleration)
{
- LZ4_stream_t_internal *streamPtr = &LZ4_stream->internal_donotuse;
- const BYTE * const dictEnd = streamPtr->dictionary
- + streamPtr->dictSize;
-
- const BYTE *smallest = (const BYTE *) source;
-
- if (streamPtr->initCheck) {
- /* Uninitialized structure detected */
- return 0;
- }
-
- if ((streamPtr->dictSize > 0) && (smallest > dictEnd))
- smallest = dictEnd;
-
- LZ4_renormDictT(streamPtr, smallest);
-
- if (acceleration < 1)
- acceleration = LZ4_ACCELERATION_DEFAULT;
-
- /* Check overlapping input/dictionary space */
- {
- const BYTE *sourceEnd = (const BYTE *) source + inputSize;
-
- if ((sourceEnd > streamPtr->dictionary)
- && (sourceEnd < dictEnd)) {
- streamPtr->dictSize = (U32)(dictEnd - sourceEnd);
- if (streamPtr->dictSize > 64 * KB)
- streamPtr->dictSize = 64 * KB;
- if (streamPtr->dictSize < 4)
- streamPtr->dictSize = 0;
- streamPtr->dictionary = dictEnd - streamPtr->dictSize;
- }
- }
-
- /* prefix mode : source data follows dictionary */
- if (dictEnd == (const BYTE *)source) {
- int result;
-
- if ((streamPtr->dictSize < 64 * KB) &&
- (streamPtr->dictSize < streamPtr->currentOffset)) {
- result = LZ4_compress_generic(
- streamPtr, source, dest, inputSize,
- maxOutputSize, limitedOutput, byU32,
- withPrefix64k, dictSmall, acceleration);
- } else {
- result = LZ4_compress_generic(
- streamPtr, source, dest, inputSize,
- maxOutputSize, limitedOutput, byU32,
- withPrefix64k, noDictIssue, acceleration);
- }
- streamPtr->dictSize += (U32)inputSize;
- streamPtr->currentOffset += (U32)inputSize;
- return result;
- }
-
- /* external dictionary mode */
- {
- int result;
-
- if ((streamPtr->dictSize < 64 * KB) &&
- (streamPtr->dictSize < streamPtr->currentOffset)) {
- result = LZ4_compress_generic(
- streamPtr, source, dest, inputSize,
- maxOutputSize, limitedOutput, byU32,
- usingExtDict, dictSmall, acceleration);
- } else {
- result = LZ4_compress_generic(
- streamPtr, source, dest, inputSize,
- maxOutputSize, limitedOutput, byU32,
- usingExtDict, noDictIssue, acceleration);
- }
- streamPtr->dictionary = (const BYTE *)source;
- streamPtr->dictSize = (U32)inputSize;
- streamPtr->currentOffset += (U32)inputSize;
- return result;
- }
+ return __lz4_compress_fast_continue(streamPtr, src, dst, srcSize,
+ maxDstSize, acceleration);
}
EXPORT_SYMBOL(LZ4_compress_fast_continue);
--
2.34.1