Skip to content

Commit

Permalink
Fix incorrect usages of repIndex across all strategies
Browse files Browse the repository at this point in the history
  • Loading branch information
@senhuang42
senhuang42 committed May 4, 2021
1 parent 6f40571 commit 8baf068
Show file tree
Hide file tree
Showing 3 changed files with 20 additions and 17 deletions.
8 changes: 4 additions & 4 deletions lib/compress/zstd_double_fast.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -409,9 +409,9 @@ static size_t ZSTD_compressBlock_doubleFast_extDict_generic(
hashSmall[hSmall] = hashLong[hLong] = curr; /* update hash table */

if ((((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow : ensure repIndex doesn't overlap dict + prefix */
& (repIndex > dictStartIndex))
& (offset_1-1 < curr - dictStartIndex))
&& (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
const BYTE* repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
const BYTE* repMatchEnd = offset_1-1 > curr - prefixStartIndex ? dictEnd : iend;
mLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repMatchEnd, prefixStart) + 4;
ip++;
ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, mLength-MINMATCH);
Expand Down Expand Up @@ -477,9 +477,9 @@ static size_t ZSTD_compressBlock_doubleFast_extDict_generic(
U32 const repIndex2 = current2 - offset_2;
const BYTE* repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2;
if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) /* intentional overflow : ensure repIndex2 doesn't overlap dict + prefix */
& (repIndex2 > dictStartIndex))
& (offset_2 < current2 - dictStartIndex))
&& (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
const BYTE* const repEnd2 = offset_2 > current2 - prefixStartIndex ? dictEnd : iend;
size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, repLength2-MINMATCH);
Expand Down
9 changes: 4 additions & 5 deletions lib/compress/zstd_fast.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -416,11 +416,10 @@ static size_t ZSTD_compressBlock_fast_extDict_generic(
const BYTE* const repMatch = repBase + repIndex;
hashTable[h] = curr; /* update hash table */
DEBUGLOG(7, "offset_1 = %u , curr = %u", offset_1, curr);
assert(offset_1 <= curr +1); /* check repIndex */

if ( (((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > dictStartIndex))
if ( (((U32)((prefixStartIndex-1) - repIndex) >= 3) /* intentional underflow */ & (offset_1-1 < curr - dictStartIndex))
&& (MEM_read32(repMatch) == MEM_read32(ip+1)) ) {
const BYTE* const repMatchEnd = repIndex < prefixStartIndex ? dictEnd : iend;
const BYTE* const repMatchEnd = (offset_1-1) > curr - prefixStartIndex ? dictEnd : iend;
size_t const rLength = ZSTD_count_2segments(ip+1 +4, repMatch +4, iend, repMatchEnd, prefixStart) + 4;
ip++;
ZSTD_storeSeq(seqStore, (size_t)(ip-anchor), anchor, iend, 0, rLength-MINMATCH);
Expand Down Expand Up @@ -453,9 +452,9 @@ static size_t ZSTD_compressBlock_fast_extDict_generic(
U32 const current2 = (U32)(ip-base);
U32 const repIndex2 = current2 - offset_2;
const BYTE* const repMatch2 = repIndex2 < prefixStartIndex ? dictBase + repIndex2 : base + repIndex2;
if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) & (repIndex2 > dictStartIndex)) /* intentional overflow */
if ( (((U32)((prefixStartIndex-1) - repIndex2) >= 3) & (offset_2 < curr - dictStartIndex)) /* intentional overflow */
&& (MEM_read32(repMatch2) == MEM_read32(ip)) ) {
const BYTE* const repEnd2 = repIndex2 < prefixStartIndex ? dictEnd : iend;
const BYTE* const repEnd2 = offset_2 > curr - prefixStartIndex ? dictEnd : iend;
size_t const repLength2 = ZSTD_count_2segments(ip+4, repMatch2+4, iend, repEnd2, prefixStart) + 4;
{ U32 const tmpOffset = offset_2; offset_2 = offset_1; offset_1 = tmpOffset; } /* swap offset_2 <=> offset_1 */
ZSTD_storeSeq(seqStore, 0 /*litlen*/, anchor, iend, 0 /*offcode*/, repLength2-MINMATCH);
Expand Down
20 changes: 12 additions & 8 deletions lib/compress/zstd_lazy.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1994,10 +1994,11 @@ size_t ZSTD_compressBlock_lazy_extDict_generic(
const U32 repIndex = (U32)(curr+1 - offset_1);
const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
const BYTE* const repMatch = repBase + repIndex;
if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow)) /* intentional overflow */
if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow */
& (offset_1-1 < curr - windowLow) )
if (MEM_read32(ip+1) == MEM_read32(repMatch)) {
/* repcode detected we should take it */
const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
const BYTE* const repEnd = offset_1-1 > curr - dictLimit ? dictEnd : iend;
matchLength = ZSTD_count_2segments(ip+1+4, repMatch+4, iend, repEnd, prefixStart) + 4;
if (depth==0) goto _storeSequence;
} }
Expand Down Expand Up @@ -2025,10 +2026,11 @@ size_t ZSTD_compressBlock_lazy_extDict_generic(
const U32 repIndex = (U32)(curr - offset_1);
const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
const BYTE* const repMatch = repBase + repIndex;
if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow)) /* intentional overflow */
if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments */
& (offset_1 < curr - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
if (MEM_read32(ip) == MEM_read32(repMatch)) {
/* repcode detected */
const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
const BYTE* const repEnd = offset_1 > curr - dictLimit ? dictEnd : iend;
size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
int const gain2 = (int)(repLength * 3);
int const gain1 = (int)(matchLength*3 - ZSTD_highbit32((U32)offset+1) + 1);
Expand Down Expand Up @@ -2056,10 +2058,11 @@ size_t ZSTD_compressBlock_lazy_extDict_generic(
const U32 repIndex = (U32)(curr - offset_1);
const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
const BYTE* const repMatch = repBase + repIndex;
if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow)) /* intentional overflow */
if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments */
& (offset_1 < curr - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
if (MEM_read32(ip) == MEM_read32(repMatch)) {
/* repcode detected */
const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
const BYTE* const repEnd = offset_1 > curr - dictLimit ? dictEnd : iend;
size_t const repLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
int const gain2 = (int)(repLength * 4);
int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offset+1) + 1);
Expand Down Expand Up @@ -2102,10 +2105,11 @@ size_t ZSTD_compressBlock_lazy_extDict_generic(
const U32 repIndex = repCurrent - offset_2;
const BYTE* const repBase = repIndex < dictLimit ? dictBase : base;
const BYTE* const repMatch = repBase + repIndex;
if (((U32)((dictLimit-1) - repIndex) >= 3) & (repIndex > windowLow)) /* intentional overflow */
if ( ((U32)((dictLimit-1) - repIndex) >= 3) /* intentional overflow : do not test positions overlapping 2 memory segments */
& (offset_2 < repCurrent - windowLow) ) /* equivalent to `curr > repIndex >= windowLow` */
if (MEM_read32(ip) == MEM_read32(repMatch)) {
/* repcode detected we should take it */
const BYTE* const repEnd = repIndex < dictLimit ? dictEnd : iend;
const BYTE* const repEnd = offset_2 > curr - dictLimit ? dictEnd : iend;
matchLength = ZSTD_count_2segments(ip+4, repMatch+4, iend, repEnd, prefixStart) + 4;
offset = offset_2; offset_2 = offset_1; offset_1 = (U32)offset; /* swap offset history */
ZSTD_storeSeq(seqStore, 0, anchor, iend, 0, matchLength-MINMATCH);
Expand Down

0 comments on commit 8baf068

Please sign in to comment.