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Remove magic constant and made other changes addressing the comments

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This commit is contained in:
Meghna Malhotra 2020-02-27 22:02:44 +05:30
parent cc7c29595d
commit 53d76dc20f
1 changed files with 22 additions and 14 deletions
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36
lib/compress/huf_compress.c
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@ -289,28 +289,34 @@ static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 maxNbBits)
return maxNbBits;
}
typedef struct {
U32 base;
U32 current;
} rankPos;
static void HUF_sort(nodeElt* huffNode, const unsigned* count, U32 maxSymbolValue, rankPos* rank)
typedef nodeElt huffNodeTable[HUF_CTABLE_WORKSPACE_SIZE_U32];
typedef struct {
rankPos rankPosition[32];
huffNodeTable huffNodeTbl;
} HUF_buildCTable_wksp_tables;
static void HUF_sort(nodeElt* huffNode, const unsigned* count, U32 maxSymbolValue, rankPos* rankPosition)
{
U32 n;
memset(rank, 0, sizeof(rankPos) * 32);
memset(rankPosition, 0, sizeof(*rankPosition));
for (n=0; n<=maxSymbolValue; n++) {
U32 r = BIT_highbit32(count[n] + 1);
rank[r].base ++;
rankPosition[r].base ++;
}
for (n=30; n>0; n--) rank[n-1].base += rank[n].base;
for (n=0; n<32; n++) rank[n].current = rank[n].base;
for (n=30; n>0; n--) rankPosition[n-1].base += rankPosition[n].base;
for (n=0; n<32; n++) rankPosition[n].current = rankPosition[n].base;
for (n=0; n<=maxSymbolValue; n++) {
U32 const c = count[n];
U32 const r = BIT_highbit32(c+1) + 1;
U32 pos = rank[r].current++;
while ((pos > rank[r].base) && (c > huffNode[pos-1].count)) {
U32 pos = rankPosition[r].current++;
while ((pos > rankPosition[r].base) && (c > huffNode[pos-1].count)) {
huffNode[pos] = huffNode[pos-1];
pos--;
}
@ -325,26 +331,28 @@ static void HUF_sort(nodeElt* huffNode, const unsigned* count, U32 maxSymbolValu
* `workSpace` must be aligned on 4-bytes boundaries, and be at least as large as a table of HUF_CTABLE_WORKSPACE_SIZE_U32 unsigned.
*/
#define STARTNODE (HUF_SYMBOLVALUE_MAX+1)
typedef nodeElt huffNodeTable[HUF_CTABLE_WORKSPACE_SIZE_U32];
size_t HUF_buildCTable_wksp (HUF_CElt* tree, const unsigned* count, U32 maxSymbolValue, U32 maxNbBits, void* workSpace, size_t wkspSize)
{
nodeElt* const huffNode0 = (nodeElt*)workSpace;
HUF_buildCTable_wksp_tables* const wksp_tables = (HUF_buildCTable_wksp_tables*)workSpace;
nodeElt* const huffNode0 = wksp_tables->huffNodeTbl;
nodeElt* const huffNode = huffNode0+1;
U32 n, nonNullRank;
int lowS, lowN;
U16 nodeNb = STARTNODE;
U32 nodeRoot;
rankPos* rank = (rankPos *)(huffNode0 + HUF_CTABLE_WORKSPACE_SIZE / sizeof(nodeElt*));
/* safety checks */
if (((size_t)workSpace & 3) != 0) return ERROR(GENERIC); /* must be aligned on 4-bytes boundaries */
if (wkspSize < sizeof(huffNodeTable) + sizeof(rankPos) * 32) return ERROR(workSpace_tooSmall);
if (wkspSize < sizeof(HUF_buildCTable_wksp_tables))
return ERROR(workSpace_tooSmall);
if (maxNbBits == 0) maxNbBits = HUF_TABLELOG_DEFAULT;
if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) return ERROR(maxSymbolValue_tooLarge);
if (maxSymbolValue > HUF_SYMBOLVALUE_MAX)
return ERROR(maxSymbolValue_tooLarge);
memset(huffNode0, 0, sizeof(huffNodeTable));
/* sort, decreasing order */
HUF_sort(huffNode, count, maxSymbolValue, rank);
HUF_sort(huffNode, count, maxSymbolValue, wksp_tables->rankPosition);
/* init for parents */
nonNullRank = maxSymbolValue;