[NOMERGE] [WIP] [RFC PATCH 1/2] lib/lz4: update LZ4 decompressor module
Gao Xiang
gaoxiang25 at huawei.com
Fri Sep 14 01:45:57 AEST 2018
Signed-off-by: Gao Xiang <gaoxiang25 at huawei.com>
---
lib/lz4/lz4_decompress.c | 481 +++++++++++++++++++++++++++++++++--------------
lib/lz4/lz4defs.h | 9 +-
2 files changed, 349 insertions(+), 141 deletions(-)
diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
index 141734d..0c9d3ad 100644
--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -43,30 +43,36 @@
/*-*****************************
* Decompression functions
*******************************/
-/* LZ4_decompress_generic() :
- * This generic decompression function cover all use cases.
- * It shall be instantiated several times, using different sets of directives
- * Note that it is important this generic function is really inlined,
+
+#define DEBUGLOG(l, ...) {} /* disabled */
+
+#ifndef assert
+#define assert(condition) ((void)0)
+#endif
+
+/*
+ * LZ4_decompress_generic() :
+ * This generic decompression function covers all use cases.
+ * It shall be instantiated several times, using different sets of directives.
+ * Note that it is important for performance that this function really get inlined,
* in order to remove useless branches during compilation optimization.
*/
static FORCE_INLINE int LZ4_decompress_generic(
- const char * const source,
- char * const dest,
- int inputSize,
+ const char * const src,
+ char * const dst,
+ int srcSize,
/*
* If endOnInput == endOnInputSize,
- * this value is the max size of Output Buffer.
+ * this value is `dstCapacity`
*/
int outputSize,
/* endOnOutputSize, endOnInputSize */
- int endOnInput,
+ endCondition_directive endOnInput,
/* full, partial */
- int partialDecoding,
- /* only used if partialDecoding == partial */
- int targetOutputSize,
+ earlyEnd_directive partialDecoding,
/* noDict, withPrefix64k, usingExtDict */
- int dict,
- /* == dest when no prefix */
+ dict_directive dict,
+ /* always <= dst, == dst when no prefix */
const BYTE * const lowPrefix,
/* only if dict == usingExtDict */
const BYTE * const dictStart,
@@ -74,35 +80,43 @@ static FORCE_INLINE int LZ4_decompress_generic(
const size_t dictSize
)
{
- /* Local Variables */
- const BYTE *ip = (const BYTE *) source;
- const BYTE * const iend = ip + inputSize;
+ const BYTE *ip = (const BYTE *) src;
+ const BYTE * const iend = ip + srcSize;
- BYTE *op = (BYTE *) dest;
+ BYTE *op = (BYTE *) dst;
BYTE * const oend = op + outputSize;
BYTE *cpy;
- BYTE *oexit = op + targetOutputSize;
- const BYTE * const lowLimit = lowPrefix - dictSize;
const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize;
- static const unsigned int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 };
- static const int dec64table[] = { 0, 0, 0, -1, 0, 1, 2, 3 };
+ static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4};
+ static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3};
const int safeDecode = (endOnInput == endOnInputSize);
const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));
+ /* Set up the "end" pointers for the shortcut. */
+ const BYTE *const shortiend = iend -
+ (endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/;
+ const BYTE *const shortoend = oend -
+ (endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/;
+
+ DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__,
+ srcSize, outputSize);
+
/* Special cases */
- /* targetOutputSize too high => decode everything */
- if ((partialDecoding) && (oexit > oend - MFLIMIT))
- oexit = oend - MFLIMIT;
+ assert(lowPrefix <= op);
+ assert(src != NULL);
/* Empty output buffer */
if ((endOnInput) && (unlikely(outputSize == 0)))
- return ((inputSize == 1) && (*ip == 0)) ? 0 : -1;
+ return ((srcSize == 1) && (*ip == 0)) ? 0 : -1;
if ((!endOnInput) && (unlikely(outputSize == 0)))
return (*ip == 0 ? 1 : -1);
+ if ((endOnInput) && unlikely(srcSize == 0))
+ return -1;
+
/* Main Loop : decode sequences */
while (1) {
size_t length;
@@ -111,12 +125,74 @@ static FORCE_INLINE int LZ4_decompress_generic(
/* get literal length */
unsigned int const token = *ip++;
-
length = token>>ML_BITS;
+ /* ip < iend before the increment */
+ assert(!endOnInput || ip <= iend);
+
+ /*
+ * A two-stage shortcut for the most common case:
+ * 1) If the literal length is 0..14, and there is enough
+ * space, enter the shortcut and copy 16 bytes on behalf
+ * of the literals (in the fast mode, only 8 bytes can be
+ * safely copied this way).
+ * 2) Further if the match length is 4..18, copy 18 bytes
+ * in a similar manner; but we ensure that there's enough
+ * space in the output for those 18 bytes earlier, upon
+ * entering the shortcut (in other words, there is a
+ * combined check for both stages).
+ */
+ if ((endOnInput ? length != RUN_MASK : length <= 8)
+ /*
+ * strictly "less than" on input, to re-enter
+ * the loop with at least one byte
+ */
+ && likely((endOnInput ? ip < shortiend : 1) &
+ (op <= shortoend))) {
+ /* Copy the literals */
+ memcpy(op, ip, endOnInput ? 16 : 8);
+ op += length; ip += length;
+
+ /*
+ * The second stage:
+ * prepare for match copying, decode full info.
+ * If it doesn't work out, the info won't be wasted.
+ */
+ length = token & ML_MASK; /* match length */
+ offset = LZ4_readLE16(ip);
+ ip += 2;
+ match = op - offset;
+ assert(match <= op); /* check overflow */
+
+ /* Do not deal with overlapping matches. */
+ if ((length != ML_MASK) &&
+ (offset >= 8) &&
+ (dict == withPrefix64k || match >= lowPrefix)) {
+ /* Copy the match. */
+ memcpy(op + 0, match + 0, 8);
+ memcpy(op + 8, match + 8, 8);
+ memcpy(op + 16, match + 16, 2);
+ op += length + MINMATCH;
+ /* Both stages worked, load the next token. */
+ continue;
+ }
+
+ /*
+ * The second stage didn't work out, but the info
+ * is ready. Propel it right to the point of match
+ * copying.
+ */
+ goto _copy_match;
+ }
+
+ /* decode literal length */
if (length == RUN_MASK) {
unsigned int s;
+ if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) {
+ /* overflow detection */
+ goto _output_error;
+ }
do {
s = *ip++;
length += s;
@@ -125,14 +201,14 @@ static FORCE_INLINE int LZ4_decompress_generic(
: 1) & (s == 255));
if ((safeDecode)
- && unlikely(
- (size_t)(op + length) < (size_t)(op))) {
+ && unlikely((uptrval)(op) +
+ length < (uptrval)(op))) {
/* overflow detection */
goto _output_error;
}
if ((safeDecode)
- && unlikely(
- (size_t)(ip + length) < (size_t)(ip))) {
+ && unlikely((uptrval)(ip) +
+ length < (uptrval)(ip))) {
/* overflow detection */
goto _output_error;
}
@@ -140,16 +216,19 @@ static FORCE_INLINE int LZ4_decompress_generic(
/* copy literals */
cpy = op + length;
- if (((endOnInput) && ((cpy > (partialDecoding ? oexit : oend - MFLIMIT))
+ LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
+
+ if (((endOnInput) && ((cpy > oend - MFLIMIT)
|| (ip + length > iend - (2 + 1 + LASTLITERALS))))
|| ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
if (partialDecoding) {
if (cpy > oend) {
/*
- * Error :
- * write attempt beyond end of output buffer
+ * Partial decoding :
+ * stop in the middle of literal segment
*/
- goto _output_error;
+ cpy = oend;
+ length = oend - op;
}
if ((endOnInput)
&& (ip + length > iend)) {
@@ -184,29 +263,43 @@ static FORCE_INLINE int LZ4_decompress_generic(
memcpy(op, ip, length);
ip += length;
op += length;
+
/* Necessarily EOF, due to parsing restrictions */
- break;
+ if (!partialDecoding || (cpy == oend))
+ break;
+ } else {
+ /* may overwrite up to WILDCOPYLENGTH beyond cpy */
+ LZ4_wildCopy(op, ip, cpy);
+ ip += length;
+ op = cpy;
}
- LZ4_wildCopy(op, ip, cpy);
- ip += length;
- op = cpy;
-
/* get offset */
offset = LZ4_readLE16(ip);
ip += 2;
match = op - offset;
- if ((checkOffset) && (unlikely(match < lowLimit))) {
+ /* get matchlength */
+ length = token & ML_MASK;
+
+_copy_match:
+ if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) {
/* Error : offset outside buffers */
goto _output_error;
}
/* costs ~1%; silence an msan warning when offset == 0 */
- LZ4_write32(op, (U32)offset);
+ /*
+ * note : when partialDecoding, there is no guarantee that
+ * at least 4 bytes remain available in output buffer
+ */
+ if (!partialDecoding) {
+ assert(oend > op);
+ assert(oend - op >= 4);
+
+ LZ4_write32(op, (U32)offset);
+ }
- /* get matchlength */
- length = token & ML_MASK;
if (length == ML_MASK) {
unsigned int s;
@@ -221,7 +314,7 @@ static FORCE_INLINE int LZ4_decompress_generic(
if ((safeDecode)
&& unlikely(
- (size_t)(op + length) < (size_t)op)) {
+ (uptrval)(op) + length < (uptrval)op)) {
/* overflow detection */
goto _output_error;
}
@@ -229,24 +322,26 @@ static FORCE_INLINE int LZ4_decompress_generic(
length += MINMATCH;
- /* check external dictionary */
+ /* match starting within external dictionary */
if ((dict == usingExtDict) && (match < lowPrefix)) {
if (unlikely(op + length > oend - LASTLITERALS)) {
/* doesn't respect parsing restriction */
- goto _output_error;
+ if (!partialDecoding)
+ goto _output_error;
+ length = min(length, (size_t)(oend - op));
}
if (length <= (size_t)(lowPrefix - match)) {
/*
- * match can be copied as a single segment
- * from external dictionary
+ * match fits entirely within external
+ * dictionary : just copy
*/
memmove(op, dictEnd - (lowPrefix - match),
length);
op += length;
} else {
/*
- * match encompass external
+ * match stretches into both external
* dictionary and current block
*/
size_t const copySize = (size_t)(lowPrefix - match);
@@ -254,7 +349,6 @@ static FORCE_INLINE int LZ4_decompress_generic(
memcpy(op, dictEnd - copySize, copySize);
op += copySize;
-
if (restSize > (size_t)(op - lowPrefix)) {
/* overlap copy */
BYTE * const endOfMatch = op + restSize;
@@ -267,23 +361,44 @@ static FORCE_INLINE int LZ4_decompress_generic(
op += restSize;
}
}
-
continue;
}
/* copy match within block */
cpy = op + length;
- if (unlikely(offset < 8)) {
- const int dec64 = dec64table[offset];
+ /*
+ * partialDecoding :
+ * may not respect endBlock parsing restrictions
+ */
+ assert(op <= oend);
+ if (partialDecoding &&
+ (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
+ size_t const mlen = min(length, (size_t)(oend - op));
+ const BYTE * const matchEnd = match + mlen;
+ BYTE * const copyEnd = op + mlen;
+
+ if (matchEnd > op) {
+ /* overlap copy */
+ while (op < copyEnd)
+ *op++ = *match++;
+ } else {
+ memcpy(op, match, mlen);
+ }
+ op = copyEnd;
+ if (op == oend)
+ break;
+ continue;
+ }
+ if (unlikely(offset < 8)) {
op[0] = match[0];
op[1] = match[1];
op[2] = match[2];
op[3] = match[3];
- match += dec32table[offset];
+ match += inc32table[offset];
memcpy(op + 4, match, 4);
- match -= dec64;
+ match -= dec64table[offset];
} else {
LZ4_copy8(op, match);
match += 8;
@@ -291,7 +406,7 @@ static FORCE_INLINE int LZ4_decompress_generic(
op += 8;
- if (unlikely(cpy > oend - 12)) {
+ if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
if (cpy > oend - LASTLITERALS) {
@@ -307,60 +422,139 @@ static FORCE_INLINE int LZ4_decompress_generic(
match += oCopyLimit - op;
op = oCopyLimit;
}
-
while (op < cpy)
*op++ = *match++;
} else {
LZ4_copy8(op, match);
-
if (length > 16)
LZ4_wildCopy(op + 8, match + 8, cpy);
}
-
- op = cpy; /* correction */
+ op = cpy; /* wildcopy correction */
}
/* end of decoding */
if (endOnInput) {
/* Nb of output bytes decoded */
- return (int) (((char *)op) - dest);
+ return (int) (((char *)op) - dst);
} else {
/* Nb of input bytes read */
- return (int) (((const char *)ip) - source);
+ return (int) (((const char *)ip) - src);
}
/* Overflow error detected */
_output_error:
- return -1;
+ return (int) (-(((const char *)ip) - src)) - 1;
}
int LZ4_decompress_safe(const char *source, char *dest,
int compressedSize, int maxDecompressedSize)
{
- return LZ4_decompress_generic(source, dest, compressedSize,
- maxDecompressedSize, endOnInputSize, full, 0,
- noDict, (BYTE *)dest, NULL, 0);
+ return LZ4_decompress_generic(source, dest,
+ compressedSize, maxDecompressedSize,
+ endOnInputSize, decode_full_block,
+ noDict, (BYTE *)dest, NULL, 0);
}
-int LZ4_decompress_safe_partial(const char *source, char *dest,
- int compressedSize, int targetOutputSize, int maxDecompressedSize)
+int LZ4_decompress_safe_partial(const char *src, char *dst,
+ int compressedSize, int targetOutputSize, int dstCapacity)
{
- return LZ4_decompress_generic(source, dest, compressedSize,
- maxDecompressedSize, endOnInputSize, partial,
- targetOutputSize, noDict, (BYTE *)dest, NULL, 0);
+ dstCapacity = min(targetOutputSize, dstCapacity);
+ return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity,
+ endOnInputSize, partial_decode,
+ noDict, (BYTE *)dst, NULL, 0);
}
int LZ4_decompress_fast(const char *source, char *dest, int originalSize)
{
return LZ4_decompress_generic(source, dest, 0, originalSize,
- endOnOutputSize, full, 0, withPrefix64k,
- (BYTE *)(dest - 64 * KB), NULL, 64 * KB);
+ endOnOutputSize, decode_full_block,
+ withPrefix64k,
+ (BYTE *)dest - 64 * KB, NULL, 0);
+}
+
+/* ===== Instantiate a few more decoding cases, used more than once. ===== */
+
+int LZ4_decompress_safe_withPrefix64k(const char *source, char *dest,
+ int compressedSize, int maxOutputSize)
+{
+ return LZ4_decompress_generic(source, dest,
+ compressedSize, maxOutputSize,
+ endOnInputSize, decode_full_block,
+ withPrefix64k,
+ (BYTE *)dest - 64 * KB, NULL, 0);
+}
+
+static int LZ4_decompress_safe_withSmallPrefix(const char *source, char *dest,
+ int compressedSize,
+ int maxOutputSize,
+ size_t prefixSize)
+{
+ return LZ4_decompress_generic(source, dest,
+ compressedSize, maxOutputSize,
+ endOnInputSize, decode_full_block,
+ noDict,
+ (BYTE *)dest - prefixSize, NULL, 0);
+}
+
+int LZ4_decompress_safe_forceExtDict(const char *source, char *dest,
+ int compressedSize, int maxOutputSize,
+ const void *dictStart, size_t dictSize)
+{
+ return LZ4_decompress_generic(source, dest,
+ compressedSize, maxOutputSize,
+ endOnInputSize, decode_full_block,
+ usingExtDict, (BYTE *)dest,
+ (const BYTE *)dictStart, dictSize);
}
+static int LZ4_decompress_fast_extDict(const char *source, char *dest,
+ int originalSize,
+ const void *dictStart, size_t dictSize)
+{
+ return LZ4_decompress_generic(source, dest,
+ 0, originalSize,
+ endOnOutputSize, decode_full_block,
+ usingExtDict, (BYTE *)dest,
+ (const BYTE *)dictStart, dictSize);
+}
+
+/*
+ * The "double dictionary" mode, for use with e.g. ring buffers: the first part
+ * of the dictionary is passed as prefix, and the second via dictStart + dictSize.
+ * These routines are used only once, in LZ4_decompress_*_continue().
+ */
+static FORCE_INLINE
+int LZ4_decompress_safe_doubleDict(const char *source, char *dest,
+ int compressedSize, int maxOutputSize,
+ size_t prefixSize,
+ const void *dictStart, size_t dictSize)
+{
+ return LZ4_decompress_generic(source, dest,
+ compressedSize, maxOutputSize,
+ endOnInputSize, decode_full_block,
+ usingExtDict, (BYTE *)dest - prefixSize,
+ (const BYTE *)dictStart, dictSize);
+}
+
+static FORCE_INLINE
+int LZ4_decompress_fast_doubleDict(const char *source, char *dest,
+ int originalSize, size_t prefixSize,
+ const void *dictStart, size_t dictSize)
+{
+ return LZ4_decompress_generic(source, dest,
+ 0, originalSize,
+ endOnOutputSize, decode_full_block,
+ usingExtDict, (BYTE *)dest - prefixSize,
+ (const BYTE *)dictStart, dictSize);
+}
+
+/* ===== streaming decompression functions ===== */
+
int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode,
const char *dictionary, int dictSize)
{
- LZ4_streamDecode_t_internal *lz4sd = (LZ4_streamDecode_t_internal *) LZ4_streamDecode;
+ LZ4_streamDecode_t_internal *lz4sd =
+ &LZ4_streamDecode->internal_donotuse;
lz4sd->prefixSize = (size_t) dictSize;
lz4sd->prefixEnd = (const BYTE *) dictionary + dictSize;
@@ -382,35 +576,51 @@ int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode,
int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode,
const char *source, char *dest, int compressedSize, int maxOutputSize)
{
- LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse;
+ LZ4_streamDecode_t_internal *lz4sd =
+ &LZ4_streamDecode->internal_donotuse;
int result;
- if (lz4sd->prefixEnd == (BYTE *)dest) {
- result = LZ4_decompress_generic(source, dest,
- compressedSize,
- maxOutputSize,
- endOnInputSize, full, 0,
- usingExtDict, lz4sd->prefixEnd - lz4sd->prefixSize,
- lz4sd->externalDict,
- lz4sd->extDictSize);
-
+ if (lz4sd->prefixSize == 0) {
+ /* The first call, no dictionary yet. */
+ assert(lz4sd->extDictSize == 0);
+ result = LZ4_decompress_safe(source, dest,
+ compressedSize, maxOutputSize);
+ if (result <= 0)
+ return result;
+ lz4sd->prefixSize = result;
+ lz4sd->prefixEnd = (BYTE *)dest + result;
+ } else if (lz4sd->prefixEnd == (BYTE *)dest) {
+ /* They're rolling the current segment. */
+ if (lz4sd->prefixSize >= 64 * KB - 1)
+ result = LZ4_decompress_safe_withPrefix64k(source, dest,
+ compressedSize, maxOutputSize);
+ else if (lz4sd->extDictSize == 0)
+ result = LZ4_decompress_safe_withSmallPrefix(source,
+ dest, compressedSize, maxOutputSize,
+ lz4sd->prefixSize);
+ else
+ result = LZ4_decompress_safe_doubleDict(source, dest,
+ compressedSize, maxOutputSize,
+ lz4sd->prefixSize,
+ lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0)
return result;
-
lz4sd->prefixSize += result;
- lz4sd->prefixEnd += result;
+ lz4sd->prefixEnd += result;
} else {
+ /*
+ * The buffer wraps around, or they're
+ * switching to another buffer.
+ */
lz4sd->extDictSize = lz4sd->prefixSize;
lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
- result = LZ4_decompress_generic(source, dest,
+ result = LZ4_decompress_safe_forceExtDict(source, dest,
compressedSize, maxOutputSize,
- endOnInputSize, full, 0,
- usingExtDict, (BYTE *)dest,
lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0)
return result;
lz4sd->prefixSize = result;
- lz4sd->prefixEnd = (BYTE *)dest + result;
+ lz4sd->prefixEnd = (BYTE *)dest + result;
}
return result;
@@ -422,75 +632,66 @@ int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode,
LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse;
int result;
- if (lz4sd->prefixEnd == (BYTE *)dest) {
- result = LZ4_decompress_generic(source, dest, 0, originalSize,
- endOnOutputSize, full, 0,
- usingExtDict,
- lz4sd->prefixEnd - lz4sd->prefixSize,
- lz4sd->externalDict, lz4sd->extDictSize);
-
+ if (lz4sd->prefixSize == 0) {
+ assert(lz4sd->extDictSize == 0);
+ result = LZ4_decompress_fast(source, dest, originalSize);
+ if (result <= 0)
+ return result;
+ lz4sd->prefixSize = originalSize;
+ lz4sd->prefixEnd = (BYTE *)dest + originalSize;
+ } else if (lz4sd->prefixEnd == (BYTE *)dest) {
+ if (lz4sd->prefixSize >= 64 * KB - 1 ||
+ lz4sd->extDictSize == 0)
+ result = LZ4_decompress_fast(source, dest,
+ originalSize);
+ else
+ result = LZ4_decompress_fast_doubleDict(source, dest,
+ originalSize, lz4sd->prefixSize,
+ lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0)
return result;
-
lz4sd->prefixSize += originalSize;
- lz4sd->prefixEnd += originalSize;
+ lz4sd->prefixEnd += originalSize;
} else {
lz4sd->extDictSize = lz4sd->prefixSize;
lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
- result = LZ4_decompress_generic(source, dest, 0, originalSize,
- endOnOutputSize, full, 0,
- usingExtDict, (BYTE *)dest,
- lz4sd->externalDict, lz4sd->extDictSize);
+ result = LZ4_decompress_fast_extDict(source, dest,
+ originalSize, lz4sd->externalDict, lz4sd->extDictSize);
if (result <= 0)
return result;
lz4sd->prefixSize = originalSize;
- lz4sd->prefixEnd = (BYTE *)dest + originalSize;
+ lz4sd->prefixEnd = (BYTE *)dest + originalSize;
}
-
return result;
}
-/*
- * Advanced decoding functions :
- * *_usingDict() :
- * These decoding functions work the same as "_continue" ones,
- * the dictionary must be explicitly provided within parameters
- */
-static FORCE_INLINE int LZ4_decompress_usingDict_generic(const char *source,
- char *dest, int compressedSize, int maxOutputSize, int safe,
- const char *dictStart, int dictSize)
+int LZ4_decompress_safe_usingDict(const char *source, char *dest,
+ int compressedSize, int maxOutputSize,
+ const char *dictStart, int dictSize)
{
if (dictSize == 0)
- return LZ4_decompress_generic(source, dest,
- compressedSize, maxOutputSize, safe, full, 0,
- noDict, (BYTE *)dest, NULL, 0);
- if (dictStart + dictSize == dest) {
- if (dictSize >= (int)(64 * KB - 1))
- return LZ4_decompress_generic(source, dest,
- compressedSize, maxOutputSize, safe, full, 0,
- withPrefix64k, (BYTE *)dest - 64 * KB, NULL, 0);
- return LZ4_decompress_generic(source, dest, compressedSize,
- maxOutputSize, safe, full, 0, noDict,
- (BYTE *)dest - dictSize, NULL, 0);
+ return LZ4_decompress_safe(source, dest,
+ compressedSize, maxOutputSize);
+ if (dictStart+dictSize == dest) {
+ if (dictSize >= 64 * KB - 1)
+ return LZ4_decompress_safe_withPrefix64k(source, dest,
+ compressedSize, maxOutputSize);
+ return LZ4_decompress_safe_withSmallPrefix(source, dest,
+ compressedSize, maxOutputSize, dictSize);
}
- return LZ4_decompress_generic(source, dest, compressedSize,
- maxOutputSize, safe, full, 0, usingExtDict,
- (BYTE *)dest, (const BYTE *)dictStart, dictSize);
-}
-
-int LZ4_decompress_safe_usingDict(const char *source, char *dest,
- int compressedSize, int maxOutputSize,
- const char *dictStart, int dictSize)
-{
- return LZ4_decompress_usingDict_generic(source, dest,
- compressedSize, maxOutputSize, 1, dictStart, dictSize);
+ return LZ4_decompress_safe_forceExtDict(source, dest,
+ compressedSize, maxOutputSize, dictStart, dictSize);
}
int LZ4_decompress_fast_usingDict(const char *source, char *dest,
- int originalSize, const char *dictStart, int dictSize)
+ int originalSize,
+ const char *dictStart, int dictSize)
{
- return LZ4_decompress_usingDict_generic(source, dest, 0,
- originalSize, 0, dictStart, dictSize);
+ if (dictSize == 0 || dictStart + dictSize == dest)
+ return LZ4_decompress_fast(source, dest, originalSize);
+
+ return LZ4_decompress_fast_extDict(source, dest, originalSize,
+ dictStart, dictSize);
}
#ifndef STATIC
diff --git a/lib/lz4/lz4defs.h b/lib/lz4/lz4defs.h
index 00a0b58..1a7fa9d 100644
--- a/lib/lz4/lz4defs.h
+++ b/lib/lz4/lz4defs.h
@@ -75,6 +75,11 @@
#define WILDCOPYLENGTH 8
#define LASTLITERALS 5
#define MFLIMIT (WILDCOPYLENGTH + MINMATCH)
+/*
+ * ensure it's possible to write 2 x wildcopyLength
+ * without overflowing output buffer
+ */
+#define MATCH_SAFEGUARD_DISTANCE ((2 * WILDCOPYLENGTH) - MINMATCH)
/* Increase this value ==> compression run slower on incompressible data */
#define LZ4_SKIPTRIGGER 6
@@ -222,6 +227,8 @@ static FORCE_INLINE unsigned int LZ4_count(
typedef enum { noDictIssue = 0, dictSmall } dictIssue_directive;
typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
-typedef enum { full = 0, partial = 1 } earlyEnd_directive;
+typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive;
+
+#define LZ4_STATIC_ASSERT(c) BUILD_BUG_ON(!(c))
#endif
--
1.9.1
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