summaryrefslogtreecommitdiffstats
path: root/lib/lz4hc.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/lz4hc.c')
-rw-r--r--lib/lz4hc.c90
1 files changed, 66 insertions, 24 deletions
diff --git a/lib/lz4hc.c b/lib/lz4hc.c
index 687f87e..aefc95b 100644
--- a/lib/lz4hc.c
+++ b/lib/lz4hc.c
@@ -490,7 +490,9 @@ LZ4_FORCE_INLINE int LZ4HC_encodeSequence (
/* Encode Literal length */
length = (size_t)(*ip - *anchor);
- if ((limit) && ((*op + (length / 255) + length + (2 + 1 + LASTLITERALS)) > oend)) return 1; /* Check output limit */
+ LZ4_STATIC_ASSERT(notLimited == 0);
+ /* Check output limit */
+ if (limit && ((*op + (length / 255) + length + (2 + 1 + LASTLITERALS)) > oend)) return 1;
if (length >= RUN_MASK) {
size_t len = length - RUN_MASK;
*token = (RUN_MASK << ML_BITS);
@@ -511,7 +513,7 @@ LZ4_FORCE_INLINE int LZ4HC_encodeSequence (
/* Encode MatchLength */
assert(matchLength >= MINMATCH);
length = (size_t)matchLength - MINMATCH;
- if ((limit) && (*op + (length / 255) + (1 + LASTLITERALS) > oend)) return 1; /* Check output limit */
+ if (limit && (*op + (length / 255) + (1 + LASTLITERALS) > oend)) return 1; /* Check output limit */
if (length >= ML_MASK) {
*token += ML_MASK;
length -= ML_MASK;
@@ -565,7 +567,7 @@ LZ4_FORCE_INLINE int LZ4HC_compress_hashChain (
/* init */
*srcSizePtr = 0;
if (limit == fillOutput) oend -= LASTLITERALS; /* Hack for support LZ4 format restriction */
- if (inputSize < LZ4_minLength) goto _last_literals; /* Input too small, no compression (all literals) */
+ if (inputSize < LZ4_minLength) goto _last_literals; /* Input too small, no compression (all literals) */
/* Main Loop */
while (ip <= mflimit) {
@@ -637,7 +639,11 @@ _Search3:
if (LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml, ref, limit, oend)) goto _dest_overflow;
ip = start2;
optr = op;
- if (LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml2, ref2, limit, oend)) goto _dest_overflow;
+ if (LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml2, ref2, limit, oend)) {
+ ml = ml2;
+ ref = ref2;
+ goto _dest_overflow;
+ }
continue;
}
@@ -709,17 +715,18 @@ _Search3:
_last_literals:
/* Encode Last Literals */
{ size_t lastRunSize = (size_t)(iend - anchor); /* literals */
- size_t litLength = (lastRunSize + 255 - RUN_MASK) / 255;
- size_t const totalSize = 1 + litLength + lastRunSize;
+ size_t llAdd = (lastRunSize + 255 - RUN_MASK) / 255;
+ size_t const totalSize = 1 + llAdd + lastRunSize;
if (limit == fillOutput) oend += LASTLITERALS; /* restore correct value */
if (limit && (op + totalSize > oend)) {
- if (limit == limitedOutput) return 0; /* Check output limit */
+ if (limit == limitedOutput) return 0;
/* adapt lastRunSize to fill 'dest' */
lastRunSize = (size_t)(oend - op) - 1;
- litLength = (lastRunSize + 255 - RUN_MASK) / 255;
- lastRunSize -= litLength;
+ llAdd = (lastRunSize + 256 - RUN_MASK) / 256;
+ lastRunSize -= llAdd;
}
- ip = anchor + lastRunSize;
+ DEBUGLOG(6, "Final literal run : %i literals", (int)lastRunSize);
+ ip = ip + lastRunSize; /* can be != iend if limit==fillOutput */
if (lastRunSize >= RUN_MASK) {
size_t accumulator = lastRunSize - RUN_MASK;
@@ -739,9 +746,23 @@ _last_literals:
_dest_overflow:
if (limit == fillOutput) {
+ /* Assumption : ip, anchor, ml and ref must be set correctly */
+ size_t const ll = (size_t)(ip - anchor);
+ size_t const ll_addbytes = (ll + 240) / 255;
+ size_t const ll_totalCost = 1 + ll_addbytes + ll;
+ BYTE* const maxLitPos = oend - 3; /* 2 for offset, 1 for token */
op = optr; /* restore correct out pointer */
+ if (op + ll_totalCost <= maxLitPos) {
+ /* ll validated; now how many matches ? */
+ size_t const bytesLeftForMl = (size_t)(maxLitPos - (op+ll_totalCost));
+ size_t const maxMlSize = MINMATCH + (ML_MASK-1) + (bytesLeftForMl * 255);
+ assert(maxMlSize < INT_MAX); assert(ml >= 0);
+ if ((size_t)ml > maxMlSize) ml = (int)maxMlSize;
+ LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml, ref, notLimited, oend);
+ }
goto _last_literals;
}
+ /* compression failed */
return 0;
}
@@ -788,7 +809,8 @@ LZ4_FORCE_INLINE int LZ4HC_compress_generic_internal (
{ lz4opt,16384,LZ4_OPT_NUM }, /* 12==LZ4HC_CLEVEL_MAX */
};
- DEBUGLOG(4, "LZ4HC_compress_generic(ctx=%p, src=%p, srcSize=%d)", ctx, src, *srcSizePtr);
+ DEBUGLOG(4, "LZ4HC_compress_generic(ctx=%p, src=%p, srcSize=%d, limit=%d)",
+ ctx, src, *srcSizePtr, limit);
if (limit == fillOutput && dstCapacity < 1) return 0; /* Impossible to store anything */
if ((U32)*srcSizePtr > (U32)LZ4_MAX_INPUT_SIZE) return 0; /* Unsupported input size (too large or negative) */
@@ -1075,8 +1097,8 @@ static int LZ4_compressHC_continue_generic (LZ4_streamHC_t* LZ4_streamHCPtr,
limitedOutput_directive limit)
{
LZ4HC_CCtx_internal* const ctxPtr = &LZ4_streamHCPtr->internal_donotuse;
- DEBUGLOG(4, "LZ4_compressHC_continue_generic(ctx=%p, src=%p, srcSize=%d)",
- LZ4_streamHCPtr, src, *srcSizePtr);
+ DEBUGLOG(5, "LZ4_compressHC_continue_generic(ctx=%p, src=%p, srcSize=%d, limit=%d)",
+ LZ4_streamHCPtr, src, *srcSizePtr, limit);
assert(ctxPtr != NULL);
/* auto-init if forgotten */
if (ctxPtr->base == NULL) LZ4HC_init_internal (ctxPtr, (const BYTE*) src);
@@ -1303,6 +1325,8 @@ static int LZ4HC_compress_optimal ( LZ4HC_CCtx_internal* ctx,
BYTE* op = (BYTE*) dst;
BYTE* opSaved = (BYTE*) dst;
BYTE* oend = op + dstCapacity;
+ int ovml = MINMATCH; /* overflow - last sequence */
+ const BYTE* ovref = NULL;
/* init */
#ifdef LZ4HC_HEAPMODE
@@ -1328,8 +1352,11 @@ static int LZ4HC_compress_optimal ( LZ4HC_CCtx_internal* ctx,
int const firstML = firstMatch.len;
const BYTE* const matchPos = ip - firstMatch.off;
opSaved = op;
- if ( LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), firstML, matchPos, limit, oend) ) /* updates ip, op and anchor */
+ if ( LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), firstML, matchPos, limit, oend) ) { /* updates ip, op and anchor */
+ ovml = firstML;
+ ovref = matchPos;
goto _dest_overflow;
+ }
continue;
}
@@ -1471,7 +1498,7 @@ static int LZ4HC_compress_optimal ( LZ4HC_CCtx_internal* ctx,
best_off = opt[last_match_pos].off;
cur = last_match_pos - best_mlen;
- encode: /* cur, last_match_pos, best_mlen, best_off must be set */
+encode: /* cur, last_match_pos, best_mlen, best_off must be set */
assert(cur < LZ4_OPT_NUM);
assert(last_match_pos >= 1); /* == 1 when only one candidate */
DEBUGLOG(6, "reverse traversal, looking for shortest path (last_match_pos=%i)", last_match_pos);
@@ -1501,12 +1528,14 @@ static int LZ4HC_compress_optimal ( LZ4HC_CCtx_internal* ctx,
assert(ml >= MINMATCH);
assert((offset >= 1) && (offset <= LZ4_DISTANCE_MAX));
opSaved = op;
- if ( LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml, ip - offset, limit, oend) ) /* updates ip, op and anchor */
+ if ( LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ml, ip - offset, limit, oend) ) { /* updates ip, op and anchor */
+ ovml = ml;
+ ovref = ip - offset;
goto _dest_overflow;
- } }
+ } } }
} /* while (ip <= mflimit) */
- _last_literals:
+_last_literals:
/* Encode Last Literals */
{ size_t lastRunSize = (size_t)(iend - anchor); /* literals */
size_t litLength = (lastRunSize + 255 - RUN_MASK) / 255;
@@ -1541,14 +1570,27 @@ static int LZ4HC_compress_optimal ( LZ4HC_CCtx_internal* ctx,
retval = (int) ((char*)op-dst);
goto _return_label;
- _dest_overflow:
- if (limit == fillOutput) {
- op = opSaved; /* restore correct out pointer */
- goto _last_literals;
+_dest_overflow:
+if (limit == fillOutput) {
+ /* Assumption : ip, anchor, ovml and ovref must be set correctly */
+ size_t const ll = (size_t)(ip - anchor);
+ size_t const ll_addbytes = (ll + 240) / 255;
+ size_t const ll_totalCost = 1 + ll_addbytes + ll;
+ BYTE* const maxLitPos = oend - 3; /* 2 for offset, 1 for token */
+ op = opSaved; /* restore correct out pointer */
+ if (op + ll_totalCost <= maxLitPos) {
+ /* ll validated; now how many matches ? */
+ size_t const bytesLeftForMl = (size_t)(maxLitPos - (op+ll_totalCost));
+ size_t const maxMlSize = MINMATCH + (ML_MASK-1) + (bytesLeftForMl * 255);
+ assert(maxMlSize < INT_MAX); assert(ovml >= 0);
+ if ((size_t)ovml > maxMlSize) ovml = (int)maxMlSize;
+ LZ4HC_encodeSequence(UPDATABLE(ip, op, anchor), ovml, ovref, notLimited, oend);
}
- _return_label:
+ goto _last_literals;
+}
+_return_label:
#ifdef LZ4HC_HEAPMODE
free(opt);
#endif
return retval;
- }
+}
generated by cgit v0.12 at 2024-10-04 12:26:34 (GMT)