diff options
Diffstat (limited to 'thirdparty/zstd/compress/fse_compress.c')
| -rw-r--r-- | thirdparty/zstd/compress/fse_compress.c | 30 |
1 files changed, 19 insertions, 11 deletions
diff --git a/thirdparty/zstd/compress/fse_compress.c b/thirdparty/zstd/compress/fse_compress.c index 549c115d42..cb8f1fa323 100644 --- a/thirdparty/zstd/compress/fse_compress.c +++ b/thirdparty/zstd/compress/fse_compress.c @@ -248,7 +248,7 @@ static size_t FSE_writeNCount_generic (void* header, size_t headerBufferSize, bitCount -= (count<max); previous0 = (count==1); if (remaining<1) return ERROR(GENERIC); - while (remaining<threshold) nbBits--, threshold>>=1; + while (remaining<threshold) { nbBits--; threshold>>=1; } } if (bitCount>16) { if ((!writeIsSafe) && (out > oend - 2)) return ERROR(dstSize_tooSmall); /* Buffer overflow */ @@ -292,7 +292,7 @@ size_t FSE_writeNCount (void* buffer, size_t bufferSize, const short* normalized It doesn't use any additional memory. But this function is unsafe : it doesn't check that all values within `src` can fit into `count`. For this reason, prefer using a table `count` with 256 elements. - @return : count of most numerous element + @return : count of most numerous element. */ size_t FSE_count_simple(unsigned* count, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize) @@ -305,7 +305,10 @@ size_t FSE_count_simple(unsigned* count, unsigned* maxSymbolValuePtr, memset(count, 0, (maxSymbolValue+1)*sizeof(*count)); if (srcSize==0) { *maxSymbolValuePtr = 0; return 0; } - while (ip<end) count[*ip++]++; + while (ip<end) { + assert(*ip <= maxSymbolValue); + count[*ip++]++; + } while (!count[maxSymbolValue]) maxSymbolValue--; *maxSymbolValuePtr = maxSymbolValue; @@ -318,7 +321,8 @@ size_t FSE_count_simple(unsigned* count, unsigned* maxSymbolValuePtr, /* FSE_count_parallel_wksp() : * Same as FSE_count_parallel(), but using an externally provided scratch buffer. - * `workSpace` size must be a minimum of `1024 * sizeof(unsigned)`` */ + * `workSpace` size must be a minimum of `1024 * sizeof(unsigned)`. + * @return : largest histogram frequency, or an error code (notably when histogram would be larger than *maxSymbolValuePtr). */ static size_t FSE_count_parallel_wksp( unsigned* count, unsigned* maxSymbolValuePtr, const void* source, size_t sourceSize, @@ -333,7 +337,7 @@ static size_t FSE_count_parallel_wksp( U32* const Counting3 = Counting2 + 256; U32* const Counting4 = Counting3 + 256; - memset(Counting1, 0, 4*256*sizeof(unsigned)); + memset(workSpace, 0, 4*256*sizeof(unsigned)); /* safety checks */ if (!sourceSize) { @@ -379,7 +383,9 @@ static size_t FSE_count_parallel_wksp( if (Counting1[s]) return ERROR(maxSymbolValue_tooSmall); } } - { U32 s; for (s=0; s<=maxSymbolValue; s++) { + { U32 s; + if (maxSymbolValue > 255) maxSymbolValue = 255; + for (s=0; s<=maxSymbolValue; s++) { count[s] = Counting1[s] + Counting2[s] + Counting3[s] + Counting4[s]; if (count[s] > max) max = count[s]; } } @@ -393,9 +399,11 @@ static size_t FSE_count_parallel_wksp( * Same as FSE_countFast(), but using an externally provided scratch buffer. * `workSpace` size must be table of >= `1024` unsigned */ size_t FSE_countFast_wksp(unsigned* count, unsigned* maxSymbolValuePtr, - const void* source, size_t sourceSize, unsigned* workSpace) + const void* source, size_t sourceSize, + unsigned* workSpace) { - if (sourceSize < 1500) return FSE_count_simple(count, maxSymbolValuePtr, source, sourceSize); + if (sourceSize < 1500) /* heuristic threshold */ + return FSE_count_simple(count, maxSymbolValuePtr, source, sourceSize); return FSE_count_parallel_wksp(count, maxSymbolValuePtr, source, sourceSize, 0, workSpace); } @@ -540,7 +548,7 @@ static size_t FSE_normalizeM2(short* norm, U32 tableLog, const unsigned* count, find max, then give all remaining points to max */ U32 maxV = 0, maxC = 0; for (s=0; s<=maxSymbolValue; s++) - if (count[s] > maxC) maxV=s, maxC=count[s]; + if (count[s] > maxC) { maxV=s; maxC=count[s]; } norm[maxV] += (short)ToDistribute; return 0; } @@ -548,7 +556,7 @@ static size_t FSE_normalizeM2(short* norm, U32 tableLog, const unsigned* count, if (total == 0) { /* all of the symbols were low enough for the lowOne or lowThreshold */ for (s=0; ToDistribute > 0; s = (s+1)%(maxSymbolValue+1)) - if (norm[s] > 0) ToDistribute--, norm[s]++; + if (norm[s] > 0) { ToDistribute--; norm[s]++; } return 0; } @@ -604,7 +612,7 @@ size_t FSE_normalizeCount (short* normalizedCounter, unsigned tableLog, U64 restToBeat = vStep * rtbTable[proba]; proba += (count[s]*step) - ((U64)proba<<scale) > restToBeat; } - if (proba > largestP) largestP=proba, largest=s; + if (proba > largestP) { largestP=proba; largest=s; } normalizedCounter[s] = proba; stillToDistribute -= proba; } } |