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-rw-r--r--lib/zstd/compress/huf_compress.c999
1 files changed, 778 insertions, 221 deletions
diff --git a/lib/zstd/compress/huf_compress.c b/lib/zstd/compress/huf_compress.c
index f76a526bfa54..0b229f5d2ae2 100644
--- a/lib/zstd/compress/huf_compress.c
+++ b/lib/zstd/compress/huf_compress.c
@@ -1,6 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
/* ******************************************************************
* Huffman encoder, part of New Generation Entropy library
- * Copyright (c) Yann Collet, Facebook, Inc.
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
*
* You can contact the author at :
* - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy
@@ -26,9 +27,9 @@
#include "hist.h"
#define FSE_STATIC_LINKING_ONLY /* FSE_optimalTableLog_internal */
#include "../common/fse.h" /* header compression */
-#define HUF_STATIC_LINKING_ONLY
#include "../common/huf.h"
#include "../common/error_private.h"
+#include "../common/bits.h" /* ZSTD_highbit32 */
/* **************************************************************
@@ -39,17 +40,93 @@
/* **************************************************************
-* Utils
+* Required declarations
****************************************************************/
-unsigned HUF_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue)
+typedef struct nodeElt_s {
+ U32 count;
+ U16 parent;
+ BYTE byte;
+ BYTE nbBits;
+} nodeElt;
+
+
+/* **************************************************************
+* Debug Traces
+****************************************************************/
+
+#if DEBUGLEVEL >= 2
+
+static size_t showU32(const U32* arr, size_t size)
{
- return FSE_optimalTableLog_internal(maxTableLog, srcSize, maxSymbolValue, 1);
+ size_t u;
+ for (u=0; u<size; u++) {
+ RAWLOG(6, " %u", arr[u]); (void)arr;
+ }
+ RAWLOG(6, " \n");
+ return size;
}
+static size_t HUF_getNbBits(HUF_CElt elt);
+
+static size_t showCTableBits(const HUF_CElt* ctable, size_t size)
+{
+ size_t u;
+ for (u=0; u<size; u++) {
+ RAWLOG(6, " %zu", HUF_getNbBits(ctable[u])); (void)ctable;
+ }
+ RAWLOG(6, " \n");
+ return size;
+
+}
+
+static size_t showHNodeSymbols(const nodeElt* hnode, size_t size)
+{
+ size_t u;
+ for (u=0; u<size; u++) {
+ RAWLOG(6, " %u", hnode[u].byte); (void)hnode;
+ }
+ RAWLOG(6, " \n");
+ return size;
+}
+
+static size_t showHNodeBits(const nodeElt* hnode, size_t size)
+{
+ size_t u;
+ for (u=0; u<size; u++) {
+ RAWLOG(6, " %u", hnode[u].nbBits); (void)hnode;
+ }
+ RAWLOG(6, " \n");
+ return size;
+}
+
+#endif
+
/* *******************************************************
* HUF : Huffman block compression
*********************************************************/
+#define HUF_WORKSPACE_MAX_ALIGNMENT 8
+
+static void* HUF_alignUpWorkspace(void* workspace, size_t* workspaceSizePtr, size_t align)
+{
+ size_t const mask = align - 1;
+ size_t const rem = (size_t)workspace & mask;
+ size_t const add = (align - rem) & mask;
+ BYTE* const aligned = (BYTE*)workspace + add;
+ assert((align & (align - 1)) == 0); /* pow 2 */
+ assert(align <= HUF_WORKSPACE_MAX_ALIGNMENT);
+ if (*workspaceSizePtr >= add) {
+ assert(add < align);
+ assert(((size_t)aligned & mask) == 0);
+ *workspaceSizePtr -= add;
+ return aligned;
+ } else {
+ *workspaceSizePtr = 0;
+ return NULL;
+ }
+}
+
+
/* HUF_compressWeights() :
* Same as FSE_compress(), but dedicated to huff0's weights compression.
* The use case needs much less stack memory.
@@ -64,7 +141,10 @@ typedef struct {
S16 norm[HUF_TABLELOG_MAX+1];
} HUF_CompressWeightsWksp;
-static size_t HUF_compressWeights(void* dst, size_t dstSize, const void* weightTable, size_t wtSize, void* workspace, size_t workspaceSize)
+static size_t
+HUF_compressWeights(void* dst, size_t dstSize,
+ const void* weightTable, size_t wtSize,
+ void* workspace, size_t workspaceSize)
{
BYTE* const ostart = (BYTE*) dst;
BYTE* op = ostart;
@@ -72,7 +152,7 @@ static size_t HUF_compressWeights(void* dst, size_t dstSize, const void* weightT
unsigned maxSymbolValue = HUF_TABLELOG_MAX;
U32 tableLog = MAX_FSE_TABLELOG_FOR_HUFF_HEADER;
- HUF_CompressWeightsWksp* wksp = (HUF_CompressWeightsWksp*)workspace;
+ HUF_CompressWeightsWksp* wksp = (HUF_CompressWeightsWksp*)HUF_alignUpWorkspace(workspace, &workspaceSize, ZSTD_ALIGNOF(U32));
if (workspaceSize < sizeof(HUF_CompressWeightsWksp)) return ERROR(GENERIC);
@@ -103,6 +183,59 @@ static size_t HUF_compressWeights(void* dst, size_t dstSize, const void* weightT
return (size_t)(op-ostart);
}
+static size_t HUF_getNbBits(HUF_CElt elt)
+{
+ return elt & 0xFF;
+}
+
+static size_t HUF_getNbBitsFast(HUF_CElt elt)
+{
+ return elt;
+}
+
+static size_t HUF_getValue(HUF_CElt elt)
+{
+ return elt & ~(size_t)0xFF;
+}
+
+static size_t HUF_getValueFast(HUF_CElt elt)
+{
+ return elt;
+}
+
+static void HUF_setNbBits(HUF_CElt* elt, size_t nbBits)
+{
+ assert(nbBits <= HUF_TABLELOG_ABSOLUTEMAX);
+ *elt = nbBits;
+}
+
+static void HUF_setValue(HUF_CElt* elt, size_t value)
+{
+ size_t const nbBits = HUF_getNbBits(*elt);
+ if (nbBits > 0) {
+ assert((value >> nbBits) == 0);
+ *elt |= value << (sizeof(HUF_CElt) * 8 - nbBits);
+ }
+}
+
+HUF_CTableHeader HUF_readCTableHeader(HUF_CElt const* ctable)
+{
+ HUF_CTableHeader header;
+ ZSTD_memcpy(&header, ctable, sizeof(header));
+ return header;
+}
+
+static void HUF_writeCTableHeader(HUF_CElt* ctable, U32 tableLog, U32 maxSymbolValue)
+{
+ HUF_CTableHeader header;
+ HUF_STATIC_ASSERT(sizeof(ctable[0]) == sizeof(header));
+ ZSTD_memset(&header, 0, sizeof(header));
+ assert(tableLog < 256);
+ header.tableLog = (BYTE)tableLog;
+ assert(maxSymbolValue < 256);
+ header.maxSymbolValue = (BYTE)maxSymbolValue;
+ ZSTD_memcpy(ctable, &header, sizeof(header));
+}
typedef struct {
HUF_CompressWeightsWksp wksp;
@@ -114,9 +247,15 @@ size_t HUF_writeCTable_wksp(void* dst, size_t maxDstSize,
const HUF_CElt* CTable, unsigned maxSymbolValue, unsigned huffLog,
void* workspace, size_t workspaceSize)
{
+ HUF_CElt const* const ct = CTable + 1;
BYTE* op = (BYTE*)dst;
U32 n;
- HUF_WriteCTableWksp* wksp = (HUF_WriteCTableWksp*)workspace;
+ HUF_WriteCTableWksp* wksp = (HUF_WriteCTableWksp*)HUF_alignUpWorkspace(workspace, &workspaceSize, ZSTD_ALIGNOF(U32));
+
+ HUF_STATIC_ASSERT(HUF_CTABLE_WORKSPACE_SIZE >= sizeof(HUF_WriteCTableWksp));
+
+ assert(HUF_readCTableHeader(CTable).maxSymbolValue == maxSymbolValue);
+ assert(HUF_readCTableHeader(CTable).tableLog == huffLog);
/* check conditions */
if (workspaceSize < sizeof(HUF_WriteCTableWksp)) return ERROR(GENERIC);
@@ -127,9 +266,10 @@ size_t HUF_writeCTable_wksp(void* dst, size_t maxDstSize,
for (n=1; n<huffLog+1; n++)
wksp->bitsToWeight[n] = (BYTE)(huffLog + 1 - n);
for (n=0; n<maxSymbolValue; n++)
- wksp->huffWeight[n] = wksp->bitsToWeight[CTable[n].nbBits];
+ wksp->huffWeight[n] = wksp->bitsToWeight[HUF_getNbBits(ct[n])];
/* attempt weights compression by FSE */
+ if (maxDstSize < 1) return ERROR(dstSize_tooSmall);
{ CHECK_V_F(hSize, HUF_compressWeights(op+1, maxDstSize-1, wksp->huffWeight, maxSymbolValue, &wksp->wksp, sizeof(wksp->wksp)) );
if ((hSize>1) & (hSize < maxSymbolValue/2)) { /* FSE compressed */
op[0] = (BYTE)hSize;
@@ -146,16 +286,6 @@ size_t HUF_writeCTable_wksp(void* dst, size_t maxDstSize,
return ((maxSymbolValue+1)/2) + 1;
}
-/*! HUF_writeCTable() :
- `CTable` : Huffman tree to save, using huf representation.
- @return : size of saved CTable */
-size_t HUF_writeCTable (void* dst, size_t maxDstSize,
- const HUF_CElt* CTable, unsigned maxSymbolValue, unsigned huffLog)
-{
- HUF_WriteCTableWksp wksp;
- return HUF_writeCTable_wksp(dst, maxDstSize, CTable, maxSymbolValue, huffLog, &wksp, sizeof(wksp));
-}
-
size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize, unsigned* hasZeroWeights)
{
@@ -163,6 +293,7 @@ size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void
U32 rankVal[HUF_TABLELOG_ABSOLUTEMAX + 1]; /* large enough for values from 0 to 16 */
U32 tableLog = 0;
U32 nbSymbols = 0;
+ HUF_CElt* const ct = CTable + 1;
/* get symbol weights */
CHECK_V_F(readSize, HUF_readStats(huffWeight, HUF_SYMBOLVALUE_MAX+1, rankVal, &nbSymbols, &tableLog, src, srcSize));
@@ -172,6 +303,10 @@ size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void
if (tableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
if (nbSymbols > *maxSymbolValuePtr+1) return ERROR(maxSymbolValue_tooSmall);
+ *maxSymbolValuePtr = nbSymbols - 1;
+
+ HUF_writeCTableHeader(CTable, tableLog, *maxSymbolValuePtr);
+
/* Prepare base value per rank */
{ U32 n, nextRankStart = 0;
for (n=1; n<=tableLog; n++) {
@@ -183,13 +318,13 @@ size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void
/* fill nbBits */
{ U32 n; for (n=0; n<nbSymbols; n++) {
const U32 w = huffWeight[n];
- CTable[n].nbBits = (BYTE)(tableLog + 1 - w) & -(w != 0);
+ HUF_setNbBits(ct + n, (BYTE)(tableLog + 1 - w) & -(w != 0));
} }
/* fill val */
{ U16 nbPerRank[HUF_TABLELOG_MAX+2] = {0}; /* support w=0=>n=tableLog+1 */
U16 valPerRank[HUF_TABLELOG_MAX+2] = {0};
- { U32 n; for (n=0; n<nbSymbols; n++) nbPerRank[CTable[n].nbBits]++; }
+ { U32 n; for (n=0; n<nbSymbols; n++) nbPerRank[HUF_getNbBits(ct[n])]++; }
/* determine stating value per rank */
valPerRank[tableLog+1] = 0; /* for w==0 */
{ U16 min = 0;
@@ -199,77 +334,74 @@ size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void
min >>= 1;
} }
/* assign value within rank, symbol order */
- { U32 n; for (n=0; n<nbSymbols; n++) CTable[n].val = valPerRank[CTable[n].nbBits]++; }
+ { U32 n; for (n=0; n<nbSymbols; n++) HUF_setValue(ct + n, valPerRank[HUF_getNbBits(ct[n])]++); }
}
- *maxSymbolValuePtr = nbSymbols - 1;
return readSize;
}
-U32 HUF_getNbBits(const void* symbolTable, U32 symbolValue)
+U32 HUF_getNbBitsFromCTable(HUF_CElt const* CTable, U32 symbolValue)
{
- const HUF_CElt* table = (const HUF_CElt*)symbolTable;
+ const HUF_CElt* const ct = CTable + 1;
assert(symbolValue <= HUF_SYMBOLVALUE_MAX);
- return table[symbolValue].nbBits;
+ if (symbolValue > HUF_readCTableHeader(CTable).maxSymbolValue)
+ return 0;
+ return (U32)HUF_getNbBits(ct[symbolValue]);
}
-typedef struct nodeElt_s {
- U32 count;
- U16 parent;
- BYTE byte;
- BYTE nbBits;
-} nodeElt;
-
/*
* HUF_setMaxHeight():
- * Enforces maxNbBits on the Huffman tree described in huffNode.
+ * Try to enforce @targetNbBits on the Huffman tree described in @huffNode.
*
- * It sets all nodes with nbBits > maxNbBits to be maxNbBits. Then it adjusts
- * the tree to so that it is a valid canonical Huffman tree.
+ * It attempts to convert all nodes with nbBits > @targetNbBits
+ * to employ @targetNbBits instead. Then it adjusts the tree
+ * so that it remains a valid canonical Huffman tree.
*
* @pre The sum of the ranks of each symbol == 2^largestBits,
* where largestBits == huffNode[lastNonNull].nbBits.
* @post The sum of the ranks of each symbol == 2^largestBits,
- * where largestBits is the return value <= maxNbBits.
+ * where largestBits is the return value (expected <= targetNbBits).
*
- * @param huffNode The Huffman tree modified in place to enforce maxNbBits.
+ * @param huffNode The Huffman tree modified in place to enforce targetNbBits.
+ * It's presumed sorted, from most frequent to rarest symbol.
* @param lastNonNull The symbol with the lowest count in the Huffman tree.
- * @param maxNbBits The maximum allowed number of bits, which the Huffman tree
+ * @param targetNbBits The allowed number of bits, which the Huffman tree
* may not respect. After this function the Huffman tree will
- * respect maxNbBits.
- * @return The maximum number of bits of the Huffman tree after adjustment,
- * necessarily no more than maxNbBits.
+ * respect targetNbBits.
+ * @return The maximum number of bits of the Huffman tree after adjustment.
*/
-static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 maxNbBits)
+static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 targetNbBits)
{
const U32 largestBits = huffNode[lastNonNull].nbBits;
- /* early exit : no elt > maxNbBits, so the tree is already valid. */
- if (largestBits <= maxNbBits) return largestBits;
+ /* early exit : no elt > targetNbBits, so the tree is already valid. */
+ if (largestBits <= targetNbBits) return largestBits;
+
+ DEBUGLOG(5, "HUF_setMaxHeight (targetNbBits = %u)", targetNbBits);
/* there are several too large elements (at least >= 2) */
{ int totalCost = 0;
- const U32 baseCost = 1 << (largestBits - maxNbBits);
+ const U32 baseCost = 1 << (largestBits - targetNbBits);
int n = (int)lastNonNull;
- /* Adjust any ranks > maxNbBits to maxNbBits.
+ /* Adjust any ranks > targetNbBits to targetNbBits.
* Compute totalCost, which is how far the sum of the ranks is
* we are over 2^largestBits after adjust the offending ranks.
*/
- while (huffNode[n].nbBits > maxNbBits) {
+ while (huffNode[n].nbBits > targetNbBits) {
totalCost += baseCost - (1 << (largestBits - huffNode[n].nbBits));
- huffNode[n].nbBits = (BYTE)maxNbBits;
+ huffNode[n].nbBits = (BYTE)targetNbBits;
n--;
}
- /* n stops at huffNode[n].nbBits <= maxNbBits */
- assert(huffNode[n].nbBits <= maxNbBits);
- /* n end at index of smallest symbol using < maxNbBits */
- while (huffNode[n].nbBits == maxNbBits) --n;
+ /* n stops at huffNode[n].nbBits <= targetNbBits */
+ assert(huffNode[n].nbBits <= targetNbBits);
+ /* n end at index of smallest symbol using < targetNbBits */
+ while (huffNode[n].nbBits == targetNbBits) --n;
- /* renorm totalCost from 2^largestBits to 2^maxNbBits
+ /* renorm totalCost from 2^largestBits to 2^targetNbBits
* note : totalCost is necessarily a multiple of baseCost */
- assert((totalCost & (baseCost - 1)) == 0);
- totalCost >>= (largestBits - maxNbBits);
+ assert(((U32)totalCost & (baseCost - 1)) == 0);
+ totalCost >>= (largestBits - targetNbBits);
assert(totalCost > 0);
/* repay normalized cost */
@@ -278,19 +410,19 @@ static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 maxNbBits)
/* Get pos of last (smallest = lowest cum. count) symbol per rank */
ZSTD_memset(rankLast, 0xF0, sizeof(rankLast));
- { U32 currentNbBits = maxNbBits;
+ { U32 currentNbBits = targetNbBits;
int pos;
for (pos=n ; pos >= 0; pos--) {
if (huffNode[pos].nbBits >= currentNbBits) continue;
- currentNbBits = huffNode[pos].nbBits; /* < maxNbBits */
- rankLast[maxNbBits-currentNbBits] = (U32)pos;
+ currentNbBits = huffNode[pos].nbBits; /* < targetNbBits */
+ rankLast[targetNbBits-currentNbBits] = (U32)pos;
} }
while (totalCost > 0) {
/* Try to reduce the next power of 2 above totalCost because we
* gain back half the rank.
*/
- U32 nBitsToDecrease = BIT_highbit32((U32)totalCost) + 1;
+ U32 nBitsToDecrease = ZSTD_highbit32((U32)totalCost) + 1;
for ( ; nBitsToDecrease > 1; nBitsToDecrease--) {
U32 const highPos = rankLast[nBitsToDecrease];
U32 const lowPos = rankLast[nBitsToDecrease-1];
@@ -330,7 +462,7 @@ static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 maxNbBits)
rankLast[nBitsToDecrease] = noSymbol;
else {
rankLast[nBitsToDecrease]--;
- if (huffNode[rankLast[nBitsToDecrease]].nbBits != maxNbBits-nBitsToDecrease)
+ if (huffNode[rankLast[nBitsToDecrease]].nbBits != targetNbBits-nBitsToDecrease)
rankLast[nBitsToDecrease] = noSymbol; /* this rank is now empty */
}
} /* while (totalCost > 0) */
@@ -342,11 +474,11 @@ static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 maxNbBits)
* TODO.
*/
while (totalCost < 0) { /* Sometimes, cost correction overshoot */
- /* special case : no rank 1 symbol (using maxNbBits-1);
- * let's create one from largest rank 0 (using maxNbBits).
+ /* special case : no rank 1 symbol (using targetNbBits-1);
+ * let's create one from largest rank 0 (using targetNbBits).
*/
if (rankLast[1] == noSymbol) {
- while (huffNode[n].nbBits == maxNbBits) n--;
+ while (huffNode[n].nbBits == targetNbBits) n--;
huffNode[n+1].nbBits--;
assert(n >= 0);
rankLast[1] = (U32)(n+1);
@@ -360,26 +492,122 @@ static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 maxNbBits)
} /* repay normalized cost */
} /* there are several too large elements (at least >= 2) */
- return maxNbBits;
+ return targetNbBits;
}
typedef struct {
- U32 base;
- U32 curr;
+ U16 base;
+ U16 curr;
} rankPos;
-typedef nodeElt huffNodeTable[HUF_CTABLE_WORKSPACE_SIZE_U32];
+typedef nodeElt huffNodeTable[2 * (HUF_SYMBOLVALUE_MAX + 1)];
-#define RANK_POSITION_TABLE_SIZE 32
+/* Number of buckets available for HUF_sort() */
+#define RANK_POSITION_TABLE_SIZE 192
typedef struct {
huffNodeTable huffNodeTbl;
rankPos rankPosition[RANK_POSITION_TABLE_SIZE];
} HUF_buildCTable_wksp_tables;
+/* RANK_POSITION_DISTINCT_COUNT_CUTOFF == Cutoff point in HUF_sort() buckets for which we use log2 bucketing.
+ * Strategy is to use as many buckets as possible for representing distinct
+ * counts while using the remainder to represent all "large" counts.
+ *
+ * To satisfy this requirement for 192 buckets, we can do the following:
+ * Let buckets 0-166 represent distinct counts of [0, 166]
+ * Let buckets 166 to 192 represent all remaining counts up to RANK_POSITION_MAX_COUNT_LOG using log2 bucketing.
+ */
+#define RANK_POSITION_MAX_COUNT_LOG 32
+#define RANK_POSITION_LOG_BUCKETS_BEGIN ((RANK_POSITION_TABLE_SIZE - 1) - RANK_POSITION_MAX_COUNT_LOG - 1 /* == 158 */)
+#define RANK_POSITION_DISTINCT_COUNT_CUTOFF (RANK_POSITION_LOG_BUCKETS_BEGIN + ZSTD_highbit32(RANK_POSITION_LOG_BUCKETS_BEGIN) /* == 166 */)
+
+/* Return the appropriate bucket index for a given count. See definition of
+ * RANK_POSITION_DISTINCT_COUNT_CUTOFF for explanation of bucketing strategy.
+ */
+static U32 HUF_getIndex(U32 const count) {
+ return (count < RANK_POSITION_DISTINCT_COUNT_CUTOFF)
+ ? count
+ : ZSTD_highbit32(count) + RANK_POSITION_LOG_BUCKETS_BEGIN;
+}
+
+/* Helper swap function for HUF_quickSortPartition() */
+static void HUF_swapNodes(nodeElt* a, nodeElt* b) {
+ nodeElt tmp = *a;
+ *a = *b;
+ *b = tmp;
+}
+
+/* Returns 0 if the huffNode array is not sorted by descending count */
+MEM_STATIC int HUF_isSorted(nodeElt huffNode[], U32 const maxSymbolValue1) {
+ U32 i;
+ for (i = 1; i < maxSymbolValue1; ++i) {
+ if (huffNode[i].count > huffNode[i-1].count) {
+ return 0;
+ }
+ }
+ return 1;
+}
+
+/* Insertion sort by descending order */
+HINT_INLINE void HUF_insertionSort(nodeElt huffNode[], int const low, int const high) {
+ int i;
+ int const size = high-low+1;
+ huffNode += low;
+ for (i = 1; i < size; ++i) {
+ nodeElt const key = huffNode[i];
+ int j = i - 1;
+ while (j >= 0 && huffNode[j].count < key.count) {
+ huffNode[j + 1] = huffNode[j];
+ j--;
+ }
+ huffNode[j + 1] = key;
+ }
+}
+
+/* Pivot helper function for quicksort. */
+static int HUF_quickSortPartition(nodeElt arr[], int const low, int const high) {
+ /* Simply select rightmost element as pivot. "Better" selectors like
+ * median-of-three don't experimentally appear to have any benefit.
+ */
+ U32 const pivot = arr[high].count;
+ int i = low - 1;
+ int j = low;
+ for ( ; j < high; j++) {
+ if (arr[j].count > pivot) {
+ i++;
+ HUF_swapNodes(&arr[i], &arr[j]);
+ }
+ }
+ HUF_swapNodes(&arr[i + 1], &arr[high]);
+ return i + 1;
+}
+
+/* Classic quicksort by descending with partially iterative calls
+ * to reduce worst case callstack size.
+ */
+static void HUF_simpleQuickSort(nodeElt arr[], int low, int high) {
+ int const kInsertionSortThreshold = 8;
+ if (high - low < kInsertionSortThreshold) {
+ HUF_insertionSort(arr, low, high);
+ return;
+ }
+ while (low < high) {
+ int const idx = HUF_quickSortPartition(arr, low, high);
+ if (idx - low < high - idx) {
+ HUF_simpleQuickSort(arr, low, idx - 1);
+ low = idx + 1;
+ } else {
+ HUF_simpleQuickSort(arr, idx + 1, high);
+ high = idx - 1;
+ }
+ }
+}
+
/*
* HUF_sort():
* Sorts the symbols [0, maxSymbolValue] by count[symbol] in decreasing order.
+ * This is a typical bucket sorting strategy that uses either quicksort or insertion sort to sort each bucket.
*
* @param[out] huffNode Sorted symbols by decreasing count. Only members `.count` and `.byte` are filled.
* Must have (maxSymbolValue + 1) entries.
@@ -387,42 +615,51 @@ typedef struct {
* @param[in] maxSymbolValue Maximum symbol value.
* @param rankPosition This is a scratch workspace. Must have RANK_POSITION_TABLE_SIZE entries.
*/
-static void HUF_sort(nodeElt* huffNode, const unsigned* count, U32 maxSymbolValue, rankPos* rankPosition)
-{
- int n;
- int const maxSymbolValue1 = (int)maxSymbolValue + 1;
+static void HUF_sort(nodeElt huffNode[], const unsigned count[], U32 const maxSymbolValue, rankPos rankPosition[]) {
+ U32 n;
+ U32 const maxSymbolValue1 = maxSymbolValue+1;
/* Compute base and set curr to base.
- * For symbol s let lowerRank = BIT_highbit32(count[n]+1) and rank = lowerRank + 1.
- * Then 2^lowerRank <= count[n]+1 <= 2^rank.
+ * For symbol s let lowerRank = HUF_getIndex(count[n]) and rank = lowerRank + 1.
+ * See HUF_getIndex to see bucketing strategy.
* We attribute each symbol to lowerRank's base value, because we want to know where
* each rank begins in the output, so for rank R we want to count ranks R+1 and above.
*/
ZSTD_memset(rankPosition, 0, sizeof(*rankPosition) * RANK_POSITION_TABLE_SIZE);
for (n = 0; n < maxSymbolValue1; ++n) {
- U32 lowerRank = BIT_highbit32(count[n] + 1);
+ U32 lowerRank = HUF_getIndex(count[n]);
+ assert(lowerRank < RANK_POSITION_TABLE_SIZE - 1);
rankPosition[lowerRank].base++;
}
+
assert(rankPosition[RANK_POSITION_TABLE_SIZE - 1].base == 0);
+ /* Set up the rankPosition table */
for (n = RANK_POSITION_TABLE_SIZE - 1; n > 0; --n) {
rankPosition[n-1].base += rankPosition[n].base;
rankPosition[n-1].curr = rankPosition[n-1].base;
}
- /* Sort */
+
+ /* Insert each symbol into their appropriate bucket, setting up rankPosition table. */
for (n = 0; n < maxSymbolValue1; ++n) {
U32 const c = count[n];
- U32 const r = BIT_highbit32(c+1) + 1;
- U32 pos = rankPosition[r].curr++;
- /* Insert into the correct position in the rank.
- * We have at most 256 symbols, so this insertion should be fine.
- */
- while ((pos > rankPosition[r].base) && (c > huffNode[pos-1].count)) {
- huffNode[pos] = huffNode[pos-1];
- pos--;
- }
+ U32 const r = HUF_getIndex(c) + 1;
+ U32 const pos = rankPosition[r].curr++;
+ assert(pos < maxSymbolValue1);
huffNode[pos].count = c;
huffNode[pos].byte = (BYTE)n;
}
+
+ /* Sort each bucket. */
+ for (n = RANK_POSITION_DISTINCT_COUNT_CUTOFF; n < RANK_POSITION_TABLE_SIZE - 1; ++n) {
+ int const bucketSize = rankPosition[n].curr - rankPosition[n].base;
+ U32 const bucketStartIdx = rankPosition[n].base;
+ if (bucketSize > 1) {
+ assert(bucketStartIdx < maxSymbolValue1);
+ HUF_simpleQuickSort(huffNode + bucketStartIdx, 0, bucketSize-1);
+ }
+ }
+
+ assert(HUF_isSorted(huffNode, maxSymbolValue1));
}
@@ -446,6 +683,7 @@ static int HUF_buildTree(nodeElt* huffNode, U32 maxSymbolValue)
int lowS, lowN;
int nodeNb = STARTNODE;
int n, nodeRoot;
+ DEBUGLOG(5, "HUF_buildTree (alphabet size = %u)", maxSymbolValue + 1);
/* init for parents */
nonNullRank = (int)maxSymbolValue;
while(huffNode[nonNullRank].count == 0) nonNullRank--;
@@ -472,6 +710,8 @@ static int HUF_buildTree(nodeElt* huffNode, U32 maxSymbolValue)
for (n=0; n<=nonNullRank; n++)
huffNode[n].nbBits = huffNode[ huffNode[n].parent ].nbBits + 1;
+ DEBUGLOG(6, "Initial distribution of bits completed (%zu sorted symbols)", showHNodeBits(huffNode, maxSymbolValue+1));
+
return nonNullRank;
}
@@ -487,6 +727,7 @@ static int HUF_buildTree(nodeElt* huffNode, U32 maxSymbolValue)
*/
static void HUF_buildCTableFromTree(HUF_CElt* CTable, nodeElt const* huffNode, int nonNullRank, U32 maxSymbolValue, U32 maxNbBits)
{
+ HUF_CElt* const ct = CTable + 1;
/* fill result into ctable (val, nbBits) */
int n;
U16 nbPerRank[HUF_TABLELOG_MAX+1] = {0};
@@ -502,130 +743,381 @@ static void HUF_buildCTableFromTree(HUF_CElt* CTable, nodeElt const* huffNode, i
min >>= 1;
} }
for (n=0; n<alphabetSize; n++)
- CTable[huffNode[n].byte].nbBits = huffNode[n].nbBits; /* push nbBits per symbol, symbol order */
+ HUF_setNbBits(ct + huffNode[n].byte, huffNode[n].nbBits); /* push nbBits per symbol, symbol order */
for (n=0; n<alphabetSize; n++)
- CTable[n].val = valPerRank[CTable[n].nbBits]++; /* assign value within rank, symbol order */
+ HUF_setValue(ct + n, valPerRank[HUF_getNbBits(ct[n])]++); /* assign value within rank, symbol order */
+
+ HUF_writeCTableHeader(CTable, maxNbBits, maxSymbolValue);
}
-size_t HUF_buildCTable_wksp (HUF_CElt* tree, const unsigned* count, U32 maxSymbolValue, U32 maxNbBits, void* workSpace, size_t wkspSize)
+size_t
+HUF_buildCTable_wksp(HUF_CElt* CTable, const unsigned* count, U32 maxSymbolValue, U32 maxNbBits,
+ void* workSpace, size_t wkspSize)
{
- HUF_buildCTable_wksp_tables* const wksp_tables = (HUF_buildCTable_wksp_tables*)workSpace;
+ HUF_buildCTable_wksp_tables* const wksp_tables =
+ (HUF_buildCTable_wksp_tables*)HUF_alignUpWorkspace(workSpace, &wkspSize, ZSTD_ALIGNOF(U32));
nodeElt* const huffNode0 = wksp_tables->huffNodeTbl;
nodeElt* const huffNode = huffNode0+1;
int nonNullRank;
+ HUF_STATIC_ASSERT(HUF_CTABLE_WORKSPACE_SIZE == sizeof(HUF_buildCTable_wksp_tables));
+
+ DEBUGLOG(5, "HUF_buildCTable_wksp (alphabet size = %u)", maxSymbolValue+1);
+
/* safety checks */
- if (((size_t)workSpace & 3) != 0) return ERROR(GENERIC); /* must be aligned on 4-bytes boundaries */
if (wkspSize < sizeof(HUF_buildCTable_wksp_tables))
- return ERROR(workSpace_tooSmall);
+ return ERROR(workSpace_tooSmall);
if (maxNbBits == 0) maxNbBits = HUF_TABLELOG_DEFAULT;
if (maxSymbolValue > HUF_SYMBOLVALUE_MAX)
- return ERROR(maxSymbolValue_tooLarge);
+ return ERROR(maxSymbolValue_tooLarge);
ZSTD_memset(huffNode0, 0, sizeof(huffNodeTable));
/* sort, decreasing order */
HUF_sort(huffNode, count, maxSymbolValue, wksp_tables->rankPosition);
+ DEBUGLOG(6, "sorted symbols completed (%zu symbols)", showHNodeSymbols(huffNode, maxSymbolValue+1));
/* build tree */
nonNullRank = HUF_buildTree(huffNode, maxSymbolValue);
- /* enforce maxTableLog */
+ /* determine and enforce maxTableLog */
maxNbBits = HUF_setMaxHeight(huffNode, (U32)nonNullRank, maxNbBits);
if (maxNbBits > HUF_TABLELOG_MAX) return ERROR(GENERIC); /* check fit into table */
- HUF_buildCTableFromTree(tree, huffNode, nonNullRank, maxSymbolValue, maxNbBits);
+ HUF_buildCTableFromTree(CTable, huffNode, nonNullRank, maxSymbolValue, maxNbBits);
return maxNbBits;
}
size_t HUF_estimateCompressedSize(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue)
{
+ HUF_CElt const* ct = CTable + 1;
size_t nbBits = 0;
int s;
for (s = 0; s <= (int)maxSymbolValue; ++s) {
- nbBits += CTable[s].nbBits * count[s];
+ nbBits += HUF_getNbBits(ct[s]) * count[s];
}
return nbBits >> 3;
}
int HUF_validateCTable(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue) {
- int bad = 0;
- int s;
- for (s = 0; s <= (int)maxSymbolValue; ++s) {
- bad |= (count[s] != 0) & (CTable[s].nbBits == 0);
- }
- return !bad;
+ HUF_CTableHeader header = HUF_readCTableHeader(CTable);
+ HUF_CElt const* ct = CTable + 1;
+ int bad = 0;
+ int s;
+
+ assert(header.tableLog <= HUF_TABLELOG_ABSOLUTEMAX);
+
+ if (header.maxSymbolValue < maxSymbolValue)
+ return 0;
+
+ for (s = 0; s <= (int)maxSymbolValue; ++s) {
+ bad |= (count[s] != 0) & (HUF_getNbBits(ct[s]) == 0);
+ }
+ return !bad;
}
size_t HUF_compressBound(size_t size) { return HUF_COMPRESSBOUND(size); }
+/* HUF_CStream_t:
+ * Huffman uses its own BIT_CStream_t implementation.
+ * There are three major differences from BIT_CStream_t:
+ * 1. HUF_addBits() takes a HUF_CElt (size_t) which is
+ * the pair (nbBits, value) in the format:
+ * format:
+ * - Bits [0, 4) = nbBits
+ * - Bits [4, 64 - nbBits) = 0
+ * - Bits [64 - nbBits, 64) = value
+ * 2. The bitContainer is built from the upper bits and
+ * right shifted. E.g. to add a new value of N bits
+ * you right shift the bitContainer by N, then or in
+ * the new value into the N upper bits.
+ * 3. The bitstream has two bit containers. You can add
+ * bits to the second container and merge them into
+ * the first container.
+ */
+
+#define HUF_BITS_IN_CONTAINER (sizeof(size_t) * 8)
+
+typedef struct {
+ size_t bitContainer[2];
+ size_t bitPos[2];
+
+ BYTE* startPtr;
+ BYTE* ptr;
+ BYTE* endPtr;
+} HUF_CStream_t;
+
+/*! HUF_initCStream():
+ * Initializes the bitstream.
+ * @returns 0 or an error code.
+ */
+static size_t HUF_initCStream(HUF_CStream_t* bitC,
+ void* startPtr, size_t dstCapacity)
+{
+ ZSTD_memset(bitC, 0, sizeof(*bitC));
+ bitC->startPtr = (BYTE*)startPtr;
+ bitC->ptr = bitC->startPtr;
+ bitC->endPtr = bitC->startPtr + dstCapacity - sizeof(bitC->bitContainer[0]);
+ if (dstCapacity <= sizeof(bitC->bitContainer[0])) return ERROR(dstSize_tooSmall);
+ return 0;
+}
+
+/*! HUF_addBits():
+ * Adds the symbol stored in HUF_CElt elt to the bitstream.
+ *
+ * @param elt The element we're adding. This is a (nbBits, value) pair.
+ * See the HUF_CStream_t docs for the format.
+ * @param idx Insert into the bitstream at this idx.
+ * @param kFast This is a template parameter. If the bitstream is guaranteed
+ * to have at least 4 unused bits after this call it may be 1,
+ * otherwise it must be 0. HUF_addBits() is faster when fast is set.
+ */
+FORCE_INLINE_TEMPLATE void HUF_addBits(HUF_CStream_t* bitC, HUF_CElt elt, int idx, int kFast)
+{
+ assert(idx <= 1);
+ assert(HUF_getNbBits(elt) <= HUF_TABLELOG_ABSOLUTEMAX);
+ /* This is efficient on x86-64 with BMI2 because shrx
+ * only reads the low 6 bits of the register. The compiler
+ * knows this and elides the mask. When fast is set,
+ * every operation can use the same value loaded from elt.
+ */
+ bitC->bitContainer[idx] >>= HUF_getNbBits(elt);
+ bitC->bitContainer[idx] |= kFast ? HUF_getValueFast(elt) : HUF_getValue(elt);
+ /* We only read the low 8 bits of bitC->bitPos[idx] so it
+ * doesn't matter that the high bits have noise from the value.
+ */
+ bitC->bitPos[idx] += HUF_getNbBitsFast(elt);
+ assert((bitC->bitPos[idx] & 0xFF) <= HUF_BITS_IN_CONTAINER);
+ /* The last 4-bits of elt are dirty if fast is set,
+ * so we must not be overwriting bits that have already been
+ * inserted into the bit container.
+ */
+#if DEBUGLEVEL >= 1
+ {
+ size_t const nbBits = HUF_getNbBits(elt);
+ size_t const dirtyBits = nbBits == 0 ? 0 : ZSTD_highbit32((U32)nbBits) + 1;
+ (void)dirtyBits;
+ /* Middle bits are 0. */
+ assert(((elt >> dirtyBits) << (dirtyBits + nbBits)) == 0);
+ /* We didn't overwrite any bits in the bit container. */
+ assert(!kFast || (bitC->bitPos[idx] & 0xFF) <= HUF_BITS_IN_CONTAINER);
+ (void)dirtyBits;
+ }
+#endif
+}
+
+FORCE_INLINE_TEMPLATE void HUF_zeroIndex1(HUF_CStream_t* bitC)
+{
+ bitC->bitContainer[1] = 0;
+ bitC->bitPos[1] = 0;
+}
+
+/*! HUF_mergeIndex1() :
+ * Merges the bit container @ index 1 into the bit container @ index 0
+ * and zeros the bit container @ index 1.
+ */
+FORCE_INLINE_TEMPLATE void HUF_mergeIndex1(HUF_CStream_t* bitC)
+{
+ assert((bitC->bitPos[1] & 0xFF) < HUF_BITS_IN_CONTAINER);
+ bitC->bitContainer[0] >>= (bitC->bitPos[1] & 0xFF);
+ bitC->bitContainer[0] |= bitC->bitContainer[1];
+ bitC->bitPos[0] += bitC->bitPos[1];
+ assert((bitC->bitPos[0] & 0xFF) <= HUF_BITS_IN_CONTAINER);
+}
+
+/*! HUF_flushBits() :
+* Flushes the bits in the bit container @ index 0.
+*
+* @post bitPos will be < 8.
+* @param kFast If kFast is set then we must know a-priori that
+* the bit container will not overflow.
+*/
+FORCE_INLINE_TEMPLATE void HUF_flushBits(HUF_CStream_t* bitC, int kFast)
+{
+ /* The upper bits of bitPos are noisy, so we must mask by 0xFF. */
+ size_t const nbBits = bitC->bitPos[0] & 0xFF;
+ size_t const nbBytes = nbBits >> 3;
+ /* The top nbBits bits of bitContainer are the ones we need. */
+ size_t const bitContainer = bitC->bitContainer[0] >> (HUF_BITS_IN_CONTAINER - nbBits);
+ /* Mask bitPos to account for the bytes we consumed. */
+ bitC->bitPos[0] &= 7;
+ assert(nbBits > 0);
+ assert(nbBits <= sizeof(bitC->bitContainer[0]) * 8);
+ assert(bitC->ptr <= bitC->endPtr);
+ MEM_writeLEST(bitC->ptr, bitContainer);
+ bitC->ptr += nbBytes;
+ assert(!kFast || bitC->ptr <= bitC->endPtr);
+ if (!kFast && bitC->ptr > bitC->endPtr) bitC->ptr = bitC->endPtr;
+ /* bitContainer doesn't need to be modified because the leftover
+ * bits are already the top bitPos bits. And we don't care about
+ * noise in the lower values.
+ */
+}
+
+/*! HUF_endMark()
+ * @returns The Huffman stream end mark: A 1-bit value = 1.
+ */
+static HUF_CElt HUF_endMark(void)
+{
+ HUF_CElt endMark;
+ HUF_setNbBits(&endMark, 1);
+ HUF_setValue(&endMark, 1);
+ return endMark;
+}
+
+/*! HUF_closeCStream() :
+ * @return Size of CStream, in bytes,
+ * or 0 if it could not fit into dstBuffer */
+static size_t HUF_closeCStream(HUF_CStream_t* bitC)
+{
+ HUF_addBits(bitC, HUF_endMark(), /* idx */ 0, /* kFast */ 0);
+ HUF_flushBits(bitC, /* kFast */ 0);
+ {
+ size_t const nbBits = bitC->bitPos[0] & 0xFF;
+ if (bitC->ptr >= bitC->endPtr) return 0; /* overflow detected */
+ return (size_t)(bitC->ptr - bitC->startPtr) + (nbBits > 0);
+ }
+}
+
FORCE_INLINE_TEMPLATE void
-HUF_encodeSymbol(BIT_CStream_t* bitCPtr, U32 symbol, const HUF_CElt* CTable)
+HUF_encodeSymbol(HUF_CStream_t* bitCPtr, U32 symbol, const HUF_CElt* CTable, int idx, int fast)
{
- BIT_addBitsFast(bitCPtr, CTable[symbol].val, CTable[symbol].nbBits);
+ HUF_addBits(bitCPtr, CTable[symbol], idx, fast);
}
-#define HUF_FLUSHBITS(s) BIT_flushBits(s)
+FORCE_INLINE_TEMPLATE void
+HUF_compress1X_usingCTable_internal_body_loop(HUF_CStream_t* bitC,
+ const BYTE* ip, size_t srcSize,
+ const HUF_CElt* ct,
+ int kUnroll, int kFastFlush, int kLastFast)
+{
+ /* Join to kUnroll */
+ int n = (int)srcSize;
+ int rem = n % kUnroll;
+ if (rem > 0) {
+ for (; rem > 0; --rem) {
+ HUF_encodeSymbol(bitC, ip[--n], ct, 0, /* fast */ 0);
+ }
+ HUF_flushBits(bitC, kFastFlush);
+ }
+ assert(n % kUnroll == 0);
-#define HUF_FLUSHBITS_1(stream) \
- if (sizeof((stream)->bitContainer)*8 < HUF_TABLELOG_MAX*2+7) HUF_FLUSHBITS(stream)
+ /* Join to 2 * kUnroll */
+ if (n % (2 * kUnroll)) {
+ int u;
+ for (u = 1; u < kUnroll; ++u) {
+ HUF_encodeSymbol(bitC, ip[n - u], ct, 0, 1);
+ }
+ HUF_encodeSymbol(bitC, ip[n - kUnroll], ct, 0, kLastFast);
+ HUF_flushBits(bitC, kFastFlush);
+ n -= kUnroll;
+ }
+ assert(n % (2 * kUnroll) == 0);
+
+ for (; n>0; n-= 2 * kUnroll) {
+ /* Encode kUnroll symbols into the bitstream @ index 0. */
+ int u;
+ for (u = 1; u < kUnroll; ++u) {
+ HUF_encodeSymbol(bitC, ip[n - u], ct, /* idx */ 0, /* fast */ 1);
+ }
+ HUF_encodeSymbol(bitC, ip[n - kUnroll], ct, /* idx */ 0, /* fast */ kLastFast);
+ HUF_flushBits(bitC, kFastFlush);
+ /* Encode kUnroll symbols into the bitstream @ index 1.
+ * This allows us to start filling the bit container
+ * without any data dependencies.
+ */
+ HUF_zeroIndex1(bitC);
+ for (u = 1; u < kUnroll; ++u) {
+ HUF_encodeSymbol(bitC, ip[n - kUnroll - u], ct, /* idx */ 1, /* fast */ 1);
+ }
+ HUF_encodeSymbol(bitC, ip[n - kUnroll - kUnroll], ct, /* idx */ 1, /* fast */ kLastFast);
+ /* Merge bitstream @ index 1 into the bitstream @ index 0 */
+ HUF_mergeIndex1(bitC);
+ HUF_flushBits(bitC, kFastFlush);
+ }
+ assert(n == 0);
+
+}
+
+/*
+ * Returns a tight upper bound on the output space needed by Huffman
+ * with 8 bytes buffer to handle over-writes. If the output is at least
+ * this large we don't need to do bounds checks during Huffman encoding.
+ */
+static size_t HUF_tightCompressBound(size_t srcSize, size_t tableLog)
+{
+ return ((srcSize * tableLog) >> 3) + 8;
+}
-#define HUF_FLUSHBITS_2(stream) \
- if (sizeof((stream)->bitContainer)*8 < HUF_TABLELOG_MAX*4+7) HUF_FLUSHBITS(stream)
FORCE_INLINE_TEMPLATE size_t
HUF_compress1X_usingCTable_internal_body(void* dst, size_t dstSize,
const void* src, size_t srcSize,
const HUF_CElt* CTable)
{
+ U32 const tableLog = HUF_readCTableHeader(CTable).tableLog;
+ HUF_CElt const* ct = CTable + 1;
const BYTE* ip = (const BYTE*) src;
BYTE* const ostart = (BYTE*)dst;
BYTE* const oend = ostart + dstSize;
- BYTE* op = ostart;
- size_t n;
- BIT_CStream_t bitC;
+ HUF_CStream_t bitC;
/* init */
if (dstSize < 8) return 0; /* not enough space to compress */
- { size_t const initErr = BIT_initCStream(&bitC, op, (size_t)(oend-op));
+ { BYTE* op = ostart;
+ size_t const initErr = HUF_initCStream(&bitC, op, (size_t)(oend-op));
if (HUF_isError(initErr)) return 0; }
- n = srcSize & ~3; /* join to mod 4 */
- switch (srcSize & 3)
- {
- case 3:
- HUF_encodeSymbol(&bitC, ip[n+ 2], CTable);
- HUF_FLUSHBITS_2(&bitC);
- ZSTD_FALLTHROUGH;
- case 2:
- HUF_encodeSymbol(&bitC, ip[n+ 1], CTable);
- HUF_FLUSHBITS_1(&bitC);
- ZSTD_FALLTHROUGH;
- case 1:
- HUF_encodeSymbol(&bitC, ip[n+ 0], CTable);
- HUF_FLUSHBITS(&bitC);
- ZSTD_FALLTHROUGH;
- case 0: ZSTD_FALLTHROUGH;
- default: break;
- }
-
- for (; n>0; n-=4) { /* note : n&3==0 at this stage */
- HUF_encodeSymbol(&bitC, ip[n- 1], CTable);
- HUF_FLUSHBITS_1(&bitC);
- HUF_encodeSymbol(&bitC, ip[n- 2], CTable);
- HUF_FLUSHBITS_2(&bitC);
- HUF_encodeSymbol(&bitC, ip[n- 3], CTable);
- HUF_FLUSHBITS_1(&bitC);
- HUF_encodeSymbol(&bitC, ip[n- 4], CTable);
- HUF_FLUSHBITS(&bitC);
- }
-
- return BIT_closeCStream(&bitC);
+ if (dstSize < HUF_tightCompressBound(srcSize, (size_t)tableLog) || tableLog > 11)
+ HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ MEM_32bits() ? 2 : 4, /* kFast */ 0, /* kLastFast */ 0);
+ else {
+ if (MEM_32bits()) {
+ switch (tableLog) {
+ case 11:
+ HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 2, /* kFastFlush */ 1, /* kLastFast */ 0);
+ break;
+ case 10: ZSTD_FALLTHROUGH;
+ case 9: ZSTD_FALLTHROUGH;
+ case 8:
+ HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 2, /* kFastFlush */ 1, /* kLastFast */ 1);
+ break;
+ case 7: ZSTD_FALLTHROUGH;
+ default:
+ HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 3, /* kFastFlush */ 1, /* kLastFast */ 1);
+ break;
+ }
+ } else {
+ switch (tableLog) {
+ case 11:
+ HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 5, /* kFastFlush */ 1, /* kLastFast */ 0);
+ break;
+ case 10:
+ HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 5, /* kFastFlush */ 1, /* kLastFast */ 1);
+ break;
+ case 9:
+ HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 6, /* kFastFlush */ 1, /* kLastFast */ 0);
+ break;
+ case 8:
+ HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 7, /* kFastFlush */ 1, /* kLastFast */ 0);
+ break;
+ case 7:
+ HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 8, /* kFastFlush */ 1, /* kLastFast */ 0);
+ break;
+ case 6: ZSTD_FALLTHROUGH;
+ default:
+ HUF_compress1X_usingCTable_internal_body_loop(&bitC, ip, srcSize, ct, /* kUnroll */ 9, /* kFastFlush */ 1, /* kLastFast */ 1);
+ break;
+ }
+ }
+ }
+ assert(bitC.ptr <= bitC.endPtr);
+
+ return HUF_closeCStream(&bitC);
}
#if DYNAMIC_BMI2
-static TARGET_ATTRIBUTE("bmi2") size_t
+static BMI2_TARGET_ATTRIBUTE size_t
HUF_compress1X_usingCTable_internal_bmi2(void* dst, size_t dstSize,
const void* src, size_t srcSize,
const HUF_CElt* CTable)
@@ -644,9 +1136,9 @@ HUF_compress1X_usingCTable_internal_default(void* dst, size_t dstSize,
static size_t
HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize,
const void* src, size_t srcSize,
- const HUF_CElt* CTable, const int bmi2)
+ const HUF_CElt* CTable, const int flags)
{
- if (bmi2) {
+ if (flags & HUF_flags_bmi2) {
return HUF_compress1X_usingCTable_internal_bmi2(dst, dstSize, src, srcSize, CTable);
}
return HUF_compress1X_usingCTable_internal_default(dst, dstSize, src, srcSize, CTable);
@@ -657,24 +1149,23 @@ HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize,
static size_t
HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize,
const void* src, size_t srcSize,
- const HUF_CElt* CTable, const int bmi2)
+ const HUF_CElt* CTable, const int flags)
{
- (void)bmi2;
+ (void)flags;
return HUF_compress1X_usingCTable_internal_body(dst, dstSize, src, srcSize, CTable);
}
#endif
-size_t HUF_compress1X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable)
+size_t HUF_compress1X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable, int flags)
{
- return HUF_compress1X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0);
+ return HUF_compress1X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, flags);
}
-
static size_t
HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize,
const void* src, size_t srcSize,
- const HUF_CElt* CTable, int bmi2)
+ const HUF_CElt* CTable, int flags)
{
size_t const segmentSize = (srcSize+3)/4; /* first 3 segments */
const BYTE* ip = (const BYTE*) src;
@@ -688,27 +1179,24 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize,
op += 6; /* jumpTable */
assert(op <= oend);
- { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
- if (cSize==0) return 0;
- assert(cSize <= 65535);
+ { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, flags) );
+ if (cSize == 0 || cSize > 65535) return 0;
MEM_writeLE16(ostart, (U16)cSize);
op += cSize;
}
ip += segmentSize;
assert(op <= oend);
- { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
- if (cSize==0) return 0;
- assert(cSize <= 65535);
+ { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, flags) );
+ if (cSize == 0 || cSize > 65535) return 0;
MEM_writeLE16(ostart+2, (U16)cSize);
op += cSize;
}
ip += segmentSize;
assert(op <= oend);
- { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, bmi2) );
- if (cSize==0) return 0;
- assert(cSize <= 65535);
+ { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, segmentSize, CTable, flags) );
+ if (cSize == 0 || cSize > 65535) return 0;
MEM_writeLE16(ostart+4, (U16)cSize);
op += cSize;
}
@@ -716,17 +1204,17 @@ HUF_compress4X_usingCTable_internal(void* dst, size_t dstSize,
ip += segmentSize;
assert(op <= oend);
assert(ip <= iend);
- { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, (size_t)(iend-ip), CTable, bmi2) );
- if (cSize==0) return 0;
+ { CHECK_V_F(cSize, HUF_compress1X_usingCTable_internal(op, (size_t)(oend-op), ip, (size_t)(iend-ip), CTable, flags) );
+ if (cSize == 0 || cSize > 65535) return 0;
op += cSize;
}
return (size_t)(op-ostart);
}
-size_t HUF_compress4X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable)
+size_t HUF_compress4X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable, int flags)
{
- return HUF_compress4X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, /* bmi2 */ 0);
+ return HUF_compress4X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, flags);
}
typedef enum { HUF_singleStream, HUF_fourStreams } HUF_nbStreams_e;
@@ -734,11 +1222,11 @@ 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,
- HUF_nbStreams_e nbStreams, const HUF_CElt* CTable, const int bmi2)
+ HUF_nbStreams_e nbStreams, const HUF_CElt* CTable, const int flags)
{
size_t const cSize = (nbStreams==HUF_singleStream) ?
- HUF_compress1X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, bmi2) :
- HUF_compress4X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, bmi2);
+ HUF_compress1X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, flags) :
+ HUF_compress4X_usingCTable_internal(op, (size_t)(oend - op), src, srcSize, CTable, flags);
if (HUF_isError(cSize)) { return cSize; }
if (cSize==0) { return 0; } /* uncompressible */
op += cSize;
@@ -750,35 +1238,113 @@ static size_t HUF_compressCTable_internal(
typedef struct {
unsigned count[HUF_SYMBOLVALUE_MAX + 1];
- HUF_CElt CTable[HUF_SYMBOLVALUE_MAX + 1];
+ HUF_CElt CTable[HUF_CTABLE_SIZE_ST(HUF_SYMBOLVALUE_MAX)];
union {
HUF_buildCTable_wksp_tables buildCTable_wksp;
HUF_WriteCTableWksp writeCTable_wksp;
+ U32 hist_wksp[HIST_WKSP_SIZE_U32];
} wksps;
} HUF_compress_tables_t;
+#define SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE 4096
+#define SUSPECT_INCOMPRESSIBLE_SAMPLE_RATIO 10 /* Must be >= 2 */
+
+unsigned HUF_cardinality(const unsigned* count, unsigned maxSymbolValue)
+{
+ unsigned cardinality = 0;
+ unsigned i;
+
+ for (i = 0; i < maxSymbolValue + 1; i++) {
+ if (count[i] != 0) cardinality += 1;
+ }
+
+ return cardinality;
+}
+
+unsigned HUF_minTableLog(unsigned symbolCardinality)
+{
+ U32 minBitsSymbols = ZSTD_highbit32(symbolCardinality) + 1;
+ return minBitsSymbols;
+}
+
+unsigned HUF_optimalTableLog(
+ unsigned maxTableLog,
+ size_t srcSize,
+ unsigned maxSymbolValue,
+ void* workSpace, size_t wkspSize,
+ HUF_CElt* table,
+ const unsigned* count,
+ int flags)
+{
+ assert(srcSize > 1); /* Not supported, RLE should be used instead */
+ assert(wkspSize >= sizeof(HUF_buildCTable_wksp_tables));
+
+ if (!(flags & HUF_flags_optimalDepth)) {
+ /* cheap evaluation, based on FSE */
+ return FSE_optimalTableLog_internal(maxTableLog, srcSize, maxSymbolValue, 1);
+ }
+
+ { BYTE* dst = (BYTE*)workSpace + sizeof(HUF_WriteCTableWksp);
+ size_t dstSize = wkspSize - sizeof(HUF_WriteCTableWksp);
+ size_t hSize, newSize;
+ const unsigned symbolCardinality = HUF_cardinality(count, maxSymbolValue);
+ const unsigned minTableLog = HUF_minTableLog(symbolCardinality);
+ size_t optSize = ((size_t) ~0) - 1;
+ unsigned optLog = maxTableLog, optLogGuess;
+
+ DEBUGLOG(6, "HUF_optimalTableLog: probing huf depth (srcSize=%zu)", srcSize);
+
+ /* Search until size increases */
+ for (optLogGuess = minTableLog; optLogGuess <= maxTableLog; optLogGuess++) {
+ DEBUGLOG(7, "checking for huffLog=%u", optLogGuess);
+
+ { size_t maxBits = HUF_buildCTable_wksp(table, count, maxSymbolValue, optLogGuess, workSpace, wkspSize);
+ if (ERR_isError(maxBits)) continue;
+
+ if (maxBits < optLogGuess && optLogGuess > minTableLog) break;
+
+ hSize = HUF_writeCTable_wksp(dst, dstSize, table, maxSymbolValue, (U32)maxBits, workSpace, wkspSize);
+ }
+
+ if (ERR_isError(hSize)) continue;
+
+ newSize = HUF_estimateCompressedSize(table, count, maxSymbolValue) + hSize;
+
+ if (newSize > optSize + 1) {
+ break;
+ }
+
+ if (newSize < optSize) {
+ optSize = newSize;
+ optLog = optLogGuess;
+ }
+ }
+ assert(optLog <= HUF_TABLELOG_MAX);
+ return optLog;
+ }
+}
+
/* HUF_compress_internal() :
* `workSpace_align4` must be aligned on 4-bytes boundaries,
- * and occupies the same space as a table of HUF_WORKSPACE_SIZE_U32 unsigned */
+ * and occupies the same space as a table of HUF_WORKSPACE_SIZE_U64 unsigned */
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_align4, size_t wkspSize,
- HUF_CElt* oldHufTable, HUF_repeat* repeat, int preferRepeat,
- const int bmi2)
+ void* workSpace, size_t wkspSize,
+ HUF_CElt* oldHufTable, HUF_repeat* repeat, int flags)
{
- HUF_compress_tables_t* const table = (HUF_compress_tables_t*)workSpace_align4;
+ HUF_compress_tables_t* const table = (HUF_compress_tables_t*)HUF_alignUpWorkspace(workSpace, &wkspSize, ZSTD_ALIGNOF(size_t));
BYTE* const ostart = (BYTE*)dst;
BYTE* const oend = ostart + dstSize;
BYTE* op = ostart;
- HUF_STATIC_ASSERT(sizeof(*table) <= HUF_WORKSPACE_SIZE);
- assert(((size_t)workSpace_align4 & 3) == 0); /* must be aligned on 4-bytes boundaries */
+ DEBUGLOG(5, "HUF_compress_internal (srcSize=%zu)", srcSize);
+ HUF_STATIC_ASSERT(sizeof(*table) + HUF_WORKSPACE_MAX_ALIGNMENT <= HUF_WORKSPACE_SIZE);
/* checks & inits */
- if (wkspSize < HUF_WORKSPACE_SIZE) return ERROR(workSpace_tooSmall);
+ if (wkspSize < sizeof(*table)) 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 */
@@ -788,17 +1354,34 @@ HUF_compress_internal (void* dst, size_t dstSize,
if (!huffLog) huffLog = HUF_TABLELOG_DEFAULT;
/* Heuristic : If old table is valid, use it for small inputs */
- if (preferRepeat && repeat && *repeat == HUF_repeat_valid) {
+ if ((flags & HUF_flags_preferRepeat) && repeat && *repeat == HUF_repeat_valid) {
return HUF_compressCTable_internal(ostart, op, oend,
src, srcSize,
- nbStreams, oldHufTable, bmi2);
+ nbStreams, oldHufTable, flags);
+ }
+
+ /* If uncompressible data is suspected, do a smaller sampling first */
+ DEBUG_STATIC_ASSERT(SUSPECT_INCOMPRESSIBLE_SAMPLE_RATIO >= 2);
+ if ((flags & HUF_flags_suspectUncompressible) && srcSize >= (SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE * SUSPECT_INCOMPRESSIBLE_SAMPLE_RATIO)) {
+ size_t largestTotal = 0;
+ DEBUGLOG(5, "input suspected incompressible : sampling to check");
+ { unsigned maxSymbolValueBegin = maxSymbolValue;
+ CHECK_V_F(largestBegin, HIST_count_simple (table->count, &maxSymbolValueBegin, (const BYTE*)src, SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE) );
+ largestTotal += largestBegin;
+ }
+ { unsigned maxSymbolValueEnd = maxSymbolValue;
+ CHECK_V_F(largestEnd, HIST_count_simple (table->count, &maxSymbolValueEnd, (const BYTE*)src + srcSize - SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE, SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE) );
+ largestTotal += largestEnd;
+ }
+ if (largestTotal <= ((2 * SUSPECT_INCOMPRESSIBLE_SAMPLE_SIZE) >> 7)+4) return 0; /* heuristic : probably not compressible enough */
}
/* Scan input and build symbol stats */
- { CHECK_V_F(largest, HIST_count_wksp (table->count, &maxSymbolValue, (const BYTE*)src, srcSize, workSpace_align4, wkspSize) );
+ { CHECK_V_F(largest, HIST_count_wksp (table->count, &maxSymbolValue, (const BYTE*)src, srcSize, table->wksps.hist_wksp, sizeof(table->wksps.hist_wksp)) );
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 */
}
+ DEBUGLOG(6, "histogram detail completed (%zu symbols)", showU32(table->count, maxSymbolValue+1));
/* Check validity of previous table */
if ( repeat
@@ -807,22 +1390,20 @@ HUF_compress_internal (void* dst, size_t dstSize,
*repeat = HUF_repeat_none;
}
/* Heuristic : use existing table for small inputs */
- if (preferRepeat && repeat && *repeat != HUF_repeat_none) {
+ if ((flags & HUF_flags_preferRepeat) && repeat && *repeat != HUF_repeat_none) {
return HUF_compressCTable_internal(ostart, op, oend,
src, srcSize,
- nbStreams, oldHufTable, bmi2);
+ nbStreams, oldHufTable, flags);
}
/* Build Huffman Tree */
- huffLog = HUF_optimalTableLog(huffLog, srcSize, maxSymbolValue);
+ huffLog = HUF_optimalTableLog(huffLog, srcSize, maxSymbolValue, &table->wksps, sizeof(table->wksps), table->CTable, table->count, flags);
{ size_t const maxBits = HUF_buildCTable_wksp(table->CTable, table->count,
maxSymbolValue, huffLog,
&table->wksps.buildCTable_wksp, sizeof(table->wksps.buildCTable_wksp));
CHECK_F(maxBits);
huffLog = (U32)maxBits;
- /* Zero unused symbols in CTable, so we can check it for validity */
- ZSTD_memset(table->CTable + (maxSymbolValue + 1), 0,
- sizeof(table->CTable) - ((maxSymbolValue + 1) * sizeof(HUF_CElt)));
+ DEBUGLOG(6, "bit distribution completed (%zu symbols)", showCTableBits(table->CTable + 1, maxSymbolValue+1));
}
/* Write table description header */
@@ -835,7 +1416,7 @@ HUF_compress_internal (void* dst, size_t dstSize,
if (oldSize <= hSize + newSize || hSize + 12 >= srcSize) {
return HUF_compressCTable_internal(ostart, op, oend,
src, srcSize,
- nbStreams, oldHufTable, bmi2);
+ nbStreams, oldHufTable, flags);
} }
/* Use the new huffman table */
@@ -847,59 +1428,35 @@ HUF_compress_internal (void* dst, size_t dstSize,
}
return HUF_compressCTable_internal(ostart, op, oend,
src, srcSize,
- nbStreams, table->CTable, bmi2);
-}
-
-
-size_t HUF_compress1X_wksp (void* dst, size_t dstSize,
- const void* src, size_t srcSize,
- unsigned maxSymbolValue, unsigned huffLog,
- void* workSpace, size_t wkspSize)
-{
- return HUF_compress_internal(dst, dstSize, src, srcSize,
- maxSymbolValue, huffLog, HUF_singleStream,
- workSpace, wkspSize,
- NULL, NULL, 0, 0 /*bmi2*/);
+ nbStreams, table->CTable, flags);
}
size_t HUF_compress1X_repeat (void* dst, size_t dstSize,
const void* src, size_t srcSize,
unsigned maxSymbolValue, unsigned huffLog,
void* workSpace, size_t wkspSize,
- HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2)
+ HUF_CElt* hufTable, HUF_repeat* repeat, int flags)
{
+ DEBUGLOG(5, "HUF_compress1X_repeat (srcSize = %zu)", srcSize);
return HUF_compress_internal(dst, dstSize, src, srcSize,
maxSymbolValue, huffLog, HUF_singleStream,
workSpace, wkspSize, hufTable,
- repeat, preferRepeat, bmi2);
+ repeat, flags);
}
/* HUF_compress4X_repeat():
* compress input using 4 streams.
- * provide workspace to generate compression tables */
-size_t HUF_compress4X_wksp (void* dst, size_t dstSize,
- const void* src, size_t srcSize,
- unsigned maxSymbolValue, unsigned huffLog,
- void* workSpace, size_t wkspSize)
-{
- return HUF_compress_internal(dst, dstSize, src, srcSize,
- maxSymbolValue, huffLog, HUF_fourStreams,
- workSpace, wkspSize,
- NULL, NULL, 0, 0 /*bmi2*/);
-}
-
-/* HUF_compress4X_repeat():
- * compress input using 4 streams.
- * re-use an existing huffman compression table */
+ * consider skipping quickly
+ * reuse an existing huffman compression table */
size_t HUF_compress4X_repeat (void* dst, size_t dstSize,
const void* src, size_t srcSize,
unsigned maxSymbolValue, unsigned huffLog,
void* workSpace, size_t wkspSize,
- HUF_CElt* hufTable, HUF_repeat* repeat, int preferRepeat, int bmi2)
+ HUF_CElt* hufTable, HUF_repeat* repeat, int flags)
{
+ DEBUGLOG(5, "HUF_compress4X_repeat (srcSize = %zu)", srcSize);
return HUF_compress_internal(dst, dstSize, src, srcSize,
maxSymbolValue, huffLog, HUF_fourStreams,
workSpace, wkspSize,
- hufTable, repeat, preferRepeat, bmi2);
+ hufTable, repeat, flags);
}
-
generated by cgit (git 2.34.1) at 2025-12-25 08:16:55 +0000