ddidderr/zstd-rs
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

introduced HUF_buildCTable_wksp(), to reduce stack memory usage

Browse Source
This commit is contained in:
Yann Collet
2016-12-01 17:47:30 -08:00
parent 850c76d045
commit a0d742b1e4
3 changed files with 49 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/compress/huf_compress.c
+32 -16
View File
@@ -325,23 +325,26 @@ static void HUF_sort(nodeElt* huffNode, const U32* count, U32 maxSymbolValue)
}
/** HUF_buildCTable() :
* Note : count is used before tree is written, so they can safely overlap
/** HUF_buildCTable_wksp() :
* Same as HUF_buildCTable(), but using externally allocated scratch buffer.
* `workSpace` must be aligned on 4-bytes boundaries, and be at least as large as a table of 1024 unsigned.
*/
#define STARTNODE (HUF_SYMBOLVALUE_MAX+1)
size_t HUF_buildCTable (HUF_CElt* tree, const U32* count, U32 maxSymbolValue, U32 maxNbBits)
typedef nodeElt huffNodeTable[2*HUF_SYMBOLVALUE_MAX+1 +1];
size_t HUF_buildCTable_wksp (HUF_CElt* tree, const U32* count, U32 maxSymbolValue, U32 maxNbBits, void* workSpace, size_t wkspSize)
{
nodeElt huffNode0[2*HUF_SYMBOLVALUE_MAX+1 +1];
nodeElt* huffNode = huffNode0 + 1;
nodeElt* const huffNode0 = (nodeElt*)workSpace;
nodeElt* const huffNode = huffNode0+1;
U32 n, nonNullRank;
int lowS, lowN;
U16 nodeNb = STARTNODE;
U32 nodeRoot;
/* safety checks */
if (wkspSize < sizeof(huffNodeTable)) return ERROR(GENERIC); /* workSpace is not large enough */
if (maxNbBits == 0) maxNbBits = HUF_TABLELOG_DEFAULT;
if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) return ERROR(GENERIC);
memset(huffNode0, 0, sizeof(huffNode0));
memset(huffNode0, 0, sizeof(huffNodeTable));
/* sort, decreasing order */
HUF_sort(huffNode, count, maxSymbolValue);
@@ -354,7 +357,7 @@ size_t HUF_buildCTable (HUF_CElt* tree, const U32* count, U32 maxSymbolValue, U3
huffNode[lowS].parent = huffNode[lowS-1].parent = nodeNb;
nodeNb++; lowS-=2;
for (n=nodeNb; n<=nodeRoot; n++) huffNode[n].count = (U32)(1U<<30);
huffNode0[0].count = (U32)(1U<<31);
huffNode0[0].count = (U32)(1U<<31); /* fake entry, strong barrier */
/* create parents */
while (nodeNb <= nodeRoot) {
@@ -397,6 +400,15 @@ size_t HUF_buildCTable (HUF_CElt* tree, const U32* count, U32 maxSymbolValue, U3
return maxNbBits;
}
/** HUF_buildCTable() :
* Note : count is used before tree is written, so they can safely overlap
*/
size_t HUF_buildCTable (HUF_CElt* tree, const U32* count, U32 maxSymbolValue, U32 maxNbBits)
{
huffNodeTable nodeTable;
return HUF_buildCTable_wksp(tree, count, maxSymbolValue, maxNbBits, nodeTable, sizeof(nodeTable));
}
static void HUF_encodeSymbol(BIT_CStream_t* bitCPtr, U32 symbol, const HUF_CElt* CTable)
{
BIT_addBitsFast(bitCPtr, CTable[symbol].val, CTable[symbol].nbBits);
@@ -503,7 +515,8 @@ static size_t HUF_compress_internal (
void* dst, size_t dstSize,
const void* src, size_t srcSize,
unsigned maxSymbolValue, unsigned huffLog,
unsigned singleStream, unsigned* workSpace)
unsigned singleStream,
void* workSpace, size_t wkspSize)
{
BYTE* const ostart = (BYTE*)dst;
BYTE* const oend = ostart + dstSize;
@@ -515,6 +528,7 @@ static size_t HUF_compress_internal (
} table; /* `count` can overlap with `CTable`; saves 1 KB */
/* checks & inits */
if (wkspSize < sizeof(huffNodeTable)) return ERROR(GENERIC);
if (!srcSize) return 0; /* Uncompressed (note : 1 means rle, so first byte must be correct) */
if (!dstSize) return 0; /* cannot fit within dst budget */
if (srcSize > HUF_BLOCKSIZE_MAX) return ERROR(srcSize_wrong); /* current block size limit */
@@ -523,14 +537,14 @@ static size_t HUF_compress_internal (
if (!huffLog) huffLog = HUF_TABLELOG_DEFAULT;
/* Scan input and build symbol stats */
{ CHECK_V_F(largest, FSE_count_wksp (table.count, &maxSymbolValue, (const BYTE*)src, srcSize, workSpace) );
{ CHECK_V_F(largest, FSE_count_wksp (table.count, &maxSymbolValue, (const BYTE*)src, srcSize, (U32*)workSpace) );
if (largest == srcSize) { *ostart = ((const BYTE*)src)[0]; return 1; } /* single symbol, rle */
if (largest <= (srcSize >> 7)+1) return 0; /* Fast heuristic : not compressible enough */
}
/* Build Huffman Tree */
huffLog = HUF_optimalTableLog(huffLog, srcSize, maxSymbolValue);
{ CHECK_V_F(maxBits, HUF_buildCTable (table.CTable, table.count, maxSymbolValue, huffLog) );
{ CHECK_V_F(maxBits, HUF_buildCTable_wksp (table.CTable, table.count, maxSymbolValue, huffLog, workSpace, wkspSize) );
huffLog = (U32)maxBits;
}
@@ -559,9 +573,10 @@ static size_t HUF_compress_internal (
size_t HUF_compress1X_wksp (void* dst, size_t dstSize,
const void* src, size_t srcSize,
unsigned maxSymbolValue, unsigned huffLog, unsigned* workSpace)
unsigned maxSymbolValue, unsigned huffLog,
void* workSpace, size_t wkspSize)
{
return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, 1 /* single stream */, workSpace);
return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, 1 /* single stream */, workSpace, wkspSize);
}
size_t HUF_compress1X (void* dst, size_t dstSize,
@@ -569,14 +584,15 @@ size_t HUF_compress1X (void* dst, size_t dstSize,
unsigned maxSymbolValue, unsigned huffLog)
{
unsigned workSpace[1024];
return HUF_compress1X_wksp(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, workSpace);
return HUF_compress1X_wksp(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, workSpace, sizeof(workSpace));
}
size_t HUF_compress4X_wksp (void* dst, size_t dstSize,
const void* src, size_t srcSize,
unsigned maxSymbolValue, unsigned huffLog, unsigned* workSpace)
unsigned maxSymbolValue, unsigned huffLog,
void* workSpace, size_t wkspSize)
{
return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, 0 /* 4 streams */, workSpace);
return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, 0 /* 4 streams */, workSpace, wkspSize);
}
size_t HUF_compress2 (void* dst, size_t dstSize,
@@ -584,7 +600,7 @@ size_t HUF_compress2 (void* dst, size_t dstSize,
unsigned maxSymbolValue, unsigned huffLog)
{
unsigned workSpace[1024];
return HUF_compress4X_wksp(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, workSpace);
return HUF_compress4X_wksp(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, workSpace, sizeof(workSpace));
}
size_t HUF_compress (void* dst, size_t maxDstSize, const void* src, size_t srcSize)