ddidderr/zstd-rs
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refactor HUF_compress_internal for clarity

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changed workspace parameter convention
to always provide workspaceSize,
so that size can be explicitly checked.

Also, use more enum to make the meaning of some parameters more explicit.
This commit is contained in:
Yann Collet
2018-10-26 13:21:37 -07:00
parent e26126caca
commit 7b74405150
6 changed files with 87 additions and 65 deletions
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lib/compress/huf_compress.c
+21 -20
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@@ -610,13 +610,14 @@ size_t HUF_compress4X_usingCTable(void* dst, size_t dstSize, const void* src, si
return HUF_compress4X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0);
}
typedef enum { HUF_singleStream, HUF_fourStreams } HUF_nbStreams_e;
static size_t HUF_compressCTable_internal(
BYTE* const ostart, BYTE* op, BYTE* const oend,
const void* src, size_t srcSize,
unsigned singleStream, const HUF_CElt* CTable, const int bmi2)
HUF_nbStreams_e nbStreams, const HUF_CElt* CTable, const int bmi2)
{
size_t const cSize = singleStream ?
size_t const cSize = (nbStreams==HUF_singleStream) ?
HUF_compress1X_usingCTable_internal(op, oend - op, src, srcSize, CTable, bmi2) :
HUF_compress4X_usingCTable_internal(op, oend - op, src, srcSize, CTable, bmi2);
if (HUF_isError(cSize)) { return cSize; }
@@ -635,14 +636,14 @@ typedef struct {
/* HUF_compress_internal() :
* `workSpace` must a table of at least HUF_WORKSPACE_SIZE_U32 unsigned */
static size_t HUF_compress_internal (
void* dst, size_t dstSize,
const void* src, size_t srcSize,
unsigned maxSymbolValue, unsigned huffLog,
unsigned singleStream,
void* workSpace, size_t wkspSize,
HUF_CElt* oldHufTable, HUF_repeat* repeat, int preferRepeat,
const int bmi2)
static size_t
HUF_compress_internal (void* dst, size_t dstSize,
const void* src, size_t srcSize,
unsigned maxSymbolValue, unsigned huffLog,
HUF_nbStreams_e nbStreams,
void* workSpace, size_t wkspSize,
HUF_CElt* oldHufTable, HUF_repeat* repeat, int preferRepeat,
const int bmi2)
{
HUF_compress_tables_t* const table = (HUF_compress_tables_t*)workSpace;
BYTE* const ostart = (BYTE*)dst;
@@ -651,7 +652,7 @@ static size_t HUF_compress_internal (
/* checks & inits */
if (((size_t)workSpace & 3) != 0) return ERROR(GENERIC); /* must be aligned on 4-bytes boundaries */
if (wkspSize < sizeof(*table)) return ERROR(workSpace_tooSmall);
if (wkspSize < HUF_WORKSPACE_SIZE) return ERROR(workSpace_tooSmall);
if (!srcSize) return 0; /* Uncompressed */
if (!dstSize) return 0; /* cannot fit anything within dst budget */
if (srcSize > HUF_BLOCKSIZE_MAX) return ERROR(srcSize_wrong); /* current block size limit */
@@ -664,11 +665,11 @@ static size_t HUF_compress_internal (
if (preferRepeat && repeat && *repeat == HUF_repeat_valid) {
return HUF_compressCTable_internal(ostart, op, oend,
src, srcSize,
singleStream, oldHufTable, bmi2);
nbStreams, oldHufTable, bmi2);
}
/* Scan input and build symbol stats */
{ CHECK_V_F(largest, HIST_count_wksp (table->count, &maxSymbolValue, (const BYTE*)src, srcSize, table->count) );
{ CHECK_V_F(largest, HIST_count_wksp (table->count, &maxSymbolValue, (const BYTE*)src, srcSize, workSpace, wkspSize) );
if (largest == srcSize) { *ostart = ((const BYTE*)src)[0]; return 1; } /* single symbol, rle */
if (largest <= (srcSize >> 7)+4) return 0; /* heuristic : probably not compressible enough */
}
@@ -683,7 +684,7 @@ static size_t HUF_compress_internal (
if (preferRepeat && repeat && *repeat != HUF_repeat_none) {
return HUF_compressCTable_internal(ostart, op, oend,
src, srcSize,
singleStream, oldHufTable, bmi2);
nbStreams, oldHufTable, bmi2);
}
/* Build Huffman Tree */
@@ -706,7 +707,7 @@ static size_t HUF_compress_internal (
if (oldSize <= hSize + newSize || hSize + 12 >= srcSize) {
return HUF_compressCTable_internal(ostart, op, oend,
src, srcSize,
singleStream, oldHufTable, bmi2);
nbStreams, oldHufTable, bmi2);
} }
/* Use the new huffman table */
@@ -718,7 +719,7 @@ static size_t HUF_compress_internal (
}
return HUF_compressCTable_internal(ostart, op, oend,
src, srcSize,
singleStream, table->CTable, bmi2);
nbStreams, table->CTable, bmi2);
}
@@ -728,7 +729,7 @@ size_t HUF_compress1X_wksp (void* dst, size_t dstSize,
void* workSpace, size_t wkspSize)
{
return HUF_compress_internal(dst, dstSize, src, srcSize,
maxSymbolValue, huffLog, 1 /*single stream*/,
maxSymbolValue, huffLog, HUF_singleStream,
workSpace, wkspSize,
NULL, NULL, 0, 0 /*bmi2*/);
}
@@ -740,7 +741,7 @@ size_t HUF_compress1X_repeat (void* dst, size_t dstSize,
HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2)
{
return HUF_compress_internal(dst, dstSize, src, srcSize,
maxSymbolValue, huffLog, 1 /*single stream*/,
maxSymbolValue, huffLog, HUF_singleStream,
workSpace, wkspSize, hufTable,
repeat, preferRepeat, bmi2);
}
@@ -762,7 +763,7 @@ size_t HUF_compress4X_wksp (void* dst, size_t dstSize,
void* workSpace, size_t wkspSize)
{
return HUF_compress_internal(dst, dstSize, src, srcSize,
maxSymbolValue, huffLog, 0 /*4 streams*/,
maxSymbolValue, huffLog, HUF_fourStreams,
workSpace, wkspSize,
NULL, NULL, 0, 0 /*bmi2*/);
}
@@ -777,7 +778,7 @@ size_t HUF_compress4X_repeat (void* dst, size_t dstSize,
HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2)
{
return HUF_compress_internal(dst, dstSize, src, srcSize,
maxSymbolValue, huffLog, 0 /* 4 streams */,
maxSymbolValue, huffLog, HUF_fourStreams,
workSpace, wkspSize,
hufTable, repeat, preferRepeat, bmi2);
}