--- /dev/null
+/* ******************************************************************
+ * Huffman encoder, part of New Generation Entropy library
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * You can contact the author at :
+ * - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy
+ * - Public forum : https://groups.google.com/forum/#!forum/lz4c
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+****************************************************************** */
+
+/* **************************************************************
+* Compiler specifics
+****************************************************************/
+#ifdef _MSC_VER /* Visual Studio */
+# pragma warning(disable : 4127) /* disable: C4127: conditional expression is constant */
+#endif
+
+
+/* **************************************************************
+* Includes
+****************************************************************/
+#include "../common/zstd_deps.h" /* ZSTD_memcpy, ZSTD_memset */
+#include "../common/compiler.h"
+#include "../common/bitstream.h"
+#include "hist.h"
+#define FSE_STATIC_LINKING_ONLY /* FSE_optimalTableLog_internal */
+#include "../common/fse.h" /* header compression */
+#include "../common/huf.h"
+#include "../common/error_private.h"
+#include "../common/bits.h" /* ZSTD_highbit32 */
+
+
+/* **************************************************************
+* Error Management
+****************************************************************/
+#define HUF_isError ERR_isError
+#define HUF_STATIC_ASSERT(c) DEBUG_STATIC_ASSERT(c) /* use only *after* variable declarations */
+
+
+/* **************************************************************
+* Required declarations
+****************************************************************/
+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)
+{
+ 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.
+ * Note : all elements within weightTable are supposed to be <= HUF_TABLELOG_MAX.
+ */
+#define MAX_FSE_TABLELOG_FOR_HUFF_HEADER 6
+
+typedef struct {
+ FSE_CTable CTable[FSE_CTABLE_SIZE_U32(MAX_FSE_TABLELOG_FOR_HUFF_HEADER, HUF_TABLELOG_MAX)];
+ U32 scratchBuffer[FSE_BUILD_CTABLE_WORKSPACE_SIZE_U32(HUF_TABLELOG_MAX, MAX_FSE_TABLELOG_FOR_HUFF_HEADER)];
+ unsigned count[HUF_TABLELOG_MAX+1];
+ 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)
+{
+ BYTE* const ostart = (BYTE*) dst;
+ BYTE* op = ostart;
+ BYTE* const oend = ostart + dstSize;
+
+ unsigned maxSymbolValue = HUF_TABLELOG_MAX;
+ U32 tableLog = MAX_FSE_TABLELOG_FOR_HUFF_HEADER;
+ HUF_CompressWeightsWksp* wksp = (HUF_CompressWeightsWksp*)HUF_alignUpWorkspace(workspace, &workspaceSize, ZSTD_ALIGNOF(U32));
+
+ if (workspaceSize < sizeof(HUF_CompressWeightsWksp)) return ERROR(GENERIC);
+
+ /* init conditions */
+ if (wtSize <= 1) return 0; /* Not compressible */
+
+ /* Scan input and build symbol stats */
+ { unsigned const maxCount = HIST_count_simple(wksp->count, &maxSymbolValue, weightTable, wtSize); /* never fails */
+ if (maxCount == wtSize) return 1; /* only a single symbol in src : rle */
+ if (maxCount == 1) return 0; /* each symbol present maximum once => not compressible */
+ }
+
+ tableLog = FSE_optimalTableLog(tableLog, wtSize, maxSymbolValue);
+ CHECK_F( FSE_normalizeCount(wksp->norm, tableLog, wksp->count, wtSize, maxSymbolValue, /* useLowProbCount */ 0) );
+
+ /* Write table description header */
+ { CHECK_V_F(hSize, FSE_writeNCount(op, (size_t)(oend-op), wksp->norm, maxSymbolValue, tableLog) );
+ op += hSize;
+ }
+
+ /* Compress */
+ CHECK_F( FSE_buildCTable_wksp(wksp->CTable, wksp->norm, maxSymbolValue, tableLog, wksp->scratchBuffer, sizeof(wksp->scratchBuffer)) );
+ { CHECK_V_F(cSize, FSE_compress_usingCTable(op, (size_t)(oend - op), weightTable, wtSize, wksp->CTable) );
+ if (cSize == 0) return 0; /* not enough space for compressed data */
+ op += cSize;
+ }
+
+ 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);
+ }
+}
+
+typedef struct {
+ HUF_CompressWeightsWksp wksp;
+ BYTE bitsToWeight[HUF_TABLELOG_MAX + 1]; /* precomputed conversion table */
+ BYTE huffWeight[HUF_SYMBOLVALUE_MAX];
+} HUF_WriteCTableWksp;
+
+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*)HUF_alignUpWorkspace(workspace, &workspaceSize, ZSTD_ALIGNOF(U32));
+
+ HUF_STATIC_ASSERT(HUF_CTABLE_WORKSPACE_SIZE >= sizeof(HUF_WriteCTableWksp));
+
+ /* check conditions */
+ if (workspaceSize < sizeof(HUF_WriteCTableWksp)) return ERROR(GENERIC);
+ if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) return ERROR(maxSymbolValue_tooLarge);
+
+ /* convert to weight */
+ wksp->bitsToWeight[0] = 0;
+ 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[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;
+ return hSize+1;
+ } }
+
+ /* write raw values as 4-bits (max : 15) */
+ if (maxSymbolValue > (256-128)) return ERROR(GENERIC); /* should not happen : likely means source cannot be compressed */
+ if (((maxSymbolValue+1)/2) + 1 > maxDstSize) return ERROR(dstSize_tooSmall); /* not enough space within dst buffer */
+ op[0] = (BYTE)(128 /*special case*/ + (maxSymbolValue-1));
+ wksp->huffWeight[maxSymbolValue] = 0; /* to be sure it doesn't cause msan issue in final combination */
+ for (n=0; n<maxSymbolValue; n+=2)
+ op[(n/2)+1] = (BYTE)((wksp->huffWeight[n] << 4) + wksp->huffWeight[n+1]);
+ return ((maxSymbolValue+1)/2) + 1;
+}
+
+
+size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize, unsigned* hasZeroWeights)
+{
+ BYTE huffWeight[HUF_SYMBOLVALUE_MAX + 1]; /* init not required, even though some static analyzer may complain */
+ 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));
+ *hasZeroWeights = (rankVal[0] > 0);
+
+ /* check result */
+ if (tableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
+ if (nbSymbols > *maxSymbolValuePtr+1) return ERROR(maxSymbolValue_tooSmall);
+
+ CTable[0] = tableLog;
+
+ /* Prepare base value per rank */
+ { U32 n, nextRankStart = 0;
+ for (n=1; n<=tableLog; n++) {
+ U32 curr = nextRankStart;
+ nextRankStart += (rankVal[n] << (n-1));
+ rankVal[n] = curr;
+ } }
+
+ /* fill nbBits */
+ { U32 n; for (n=0; n<nbSymbols; n++) {
+ const U32 w = huffWeight[n];
+ 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[HUF_getNbBits(ct[n])]++; }
+ /* determine stating value per rank */
+ valPerRank[tableLog+1] = 0; /* for w==0 */
+ { U16 min = 0;
+ U32 n; for (n=tableLog; n>0; n--) { /* start at n=tablelog <-> w=1 */
+ valPerRank[n] = min; /* get starting value within each rank */
+ min += nbPerRank[n];
+ min >>= 1;
+ } }
+ /* assign value within rank, symbol order */
+ { U32 n; for (n=0; n<nbSymbols; n++) HUF_setValue(ct + n, valPerRank[HUF_getNbBits(ct[n])]++); }
+ }
+
+ *maxSymbolValuePtr = nbSymbols - 1;
+ return readSize;
+}
+
+U32 HUF_getNbBitsFromCTable(HUF_CElt const* CTable, U32 symbolValue)
+{
+ const HUF_CElt* const ct = CTable + 1;
+ assert(symbolValue <= HUF_SYMBOLVALUE_MAX);
+ return (U32)HUF_getNbBits(ct[symbolValue]);
+}
+
+
+/**
+ * HUF_setMaxHeight():
+ * Try to enforce @targetNbBits on the Huffman tree described in @huffNode.
+ *
+ * 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 (expected <= targetNbBits).
+ *
+ * @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 targetNbBits The allowed number of bits, which the Huffman tree
+ * may not respect. After this function the Huffman tree will
+ * respect targetNbBits.
+ * @return The maximum number of bits of the Huffman tree after adjustment.
+ */
+static U32 HUF_setMaxHeight(nodeElt* huffNode, U32 lastNonNull, U32 targetNbBits)
+{
+ const U32 largestBits = huffNode[lastNonNull].nbBits;
+ /* 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 - targetNbBits);
+ int n = (int)lastNonNull;
+
+ /* 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 > targetNbBits) {
+ totalCost += baseCost - (1 << (largestBits - huffNode[n].nbBits));
+ huffNode[n].nbBits = (BYTE)targetNbBits;
+ 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^targetNbBits
+ * note : totalCost is necessarily a multiple of baseCost */
+ assert(((U32)totalCost & (baseCost - 1)) == 0);
+ totalCost >>= (largestBits - targetNbBits);
+ assert(totalCost > 0);
+
+ /* repay normalized cost */
+ { U32 const noSymbol = 0xF0F0F0F0;
+ U32 rankLast[HUF_TABLELOG_MAX+2];
+
+ /* Get pos of last (smallest = lowest cum. count) symbol per rank */
+ ZSTD_memset(rankLast, 0xF0, sizeof(rankLast));
+ { U32 currentNbBits = targetNbBits;
+ int pos;
+ for (pos=n ; pos >= 0; pos--) {
+ if (huffNode[pos].nbBits >= currentNbBits) continue;
+ 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 = ZSTD_highbit32((U32)totalCost) + 1;
+ for ( ; nBitsToDecrease > 1; nBitsToDecrease--) {
+ U32 const highPos = rankLast[nBitsToDecrease];
+ U32 const lowPos = rankLast[nBitsToDecrease-1];
+ if (highPos == noSymbol) continue;
+ /* Decrease highPos if no symbols of lowPos or if it is
+ * not cheaper to remove 2 lowPos than highPos.
+ */
+ if (lowPos == noSymbol) break;
+ { U32 const highTotal = huffNode[highPos].count;
+ U32 const lowTotal = 2 * huffNode[lowPos].count;
+ if (highTotal <= lowTotal) break;
+ } }
+ /* only triggered when no more rank 1 symbol left => find closest one (note : there is necessarily at least one !) */
+ assert(rankLast[nBitsToDecrease] != noSymbol || nBitsToDecrease == 1);
+ /* HUF_MAX_TABLELOG test just to please gcc 5+; but it should not be necessary */
+ while ((nBitsToDecrease<=HUF_TABLELOG_MAX) && (rankLast[nBitsToDecrease] == noSymbol))
+ nBitsToDecrease++;
+ assert(rankLast[nBitsToDecrease] != noSymbol);
+ /* Increase the number of bits to gain back half the rank cost. */
+ totalCost -= 1 << (nBitsToDecrease-1);
+ huffNode[rankLast[nBitsToDecrease]].nbBits++;
+
+ /* Fix up the new rank.
+ * If the new rank was empty, this symbol is now its smallest.
+ * Otherwise, this symbol will be the largest in the new rank so no adjustment.
+ */
+ if (rankLast[nBitsToDecrease-1] == noSymbol)
+ rankLast[nBitsToDecrease-1] = rankLast[nBitsToDecrease];
+ /* Fix up the old rank.
+ * If the symbol was at position 0, meaning it was the highest weight symbol in the tree,
+ * it must be the only symbol in its rank, so the old rank now has no symbols.
+ * Otherwise, since the Huffman nodes are sorted by count, the previous position is now
+ * the smallest node in the rank. If the previous position belongs to a different rank,
+ * then the rank is now empty.
+ */
+ if (rankLast[nBitsToDecrease] == 0) /* special case, reached largest symbol */
+ rankLast[nBitsToDecrease] = noSymbol;
+ else {
+ rankLast[nBitsToDecrease]--;
+ if (huffNode[rankLast[nBitsToDecrease]].nbBits != targetNbBits-nBitsToDecrease)
+ rankLast[nBitsToDecrease] = noSymbol; /* this rank is now empty */
+ }
+ } /* while (totalCost > 0) */
+
+ /* If we've removed too much weight, then we have to add it back.
+ * To avoid overshooting again, we only adjust the smallest rank.
+ * We take the largest nodes from the lowest rank 0 and move them
+ * to rank 1. There's guaranteed to be enough rank 0 symbols because
+ * TODO.
+ */
+ while (totalCost < 0) { /* Sometimes, cost correction overshoot */
+ /* 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 == targetNbBits) n--;
+ huffNode[n+1].nbBits--;
+ assert(n >= 0);
+ rankLast[1] = (U32)(n+1);
+ totalCost++;
+ continue;
+ }
+ huffNode[ rankLast[1] + 1 ].nbBits--;
+ rankLast[1]++;
+ totalCost ++;
+ }
+ } /* repay normalized cost */
+ } /* there are several too large elements (at least >= 2) */
+
+ return targetNbBits;
+}
+
+typedef struct {
+ U16 base;
+ U16 curr;
+} rankPos;
+
+typedef nodeElt huffNodeTable[2 * (HUF_SYMBOLVALUE_MAX + 1)];
+
+/* 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.
+ * @param[in] count Histogram of the symbols.
+ * @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 const maxSymbolValue, rankPos rankPosition[]) {
+ U32 n;
+ U32 const maxSymbolValue1 = maxSymbolValue+1;
+
+ /* Compute base and set curr to base.
+ * 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 = 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;
+ }
+
+ /* 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 = 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));
+}
+
+
+/** 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 sizeof(HUF_buildCTable_wksp_tables).
+ */
+#define STARTNODE (HUF_SYMBOLVALUE_MAX+1)
+
+/* HUF_buildTree():
+ * Takes the huffNode array sorted by HUF_sort() and builds an unlimited-depth Huffman tree.
+ *
+ * @param huffNode The array sorted by HUF_sort(). Builds the Huffman tree in this array.
+ * @param maxSymbolValue The maximum symbol value.
+ * @return The smallest node in the Huffman tree (by count).
+ */
+static int HUF_buildTree(nodeElt* huffNode, U32 maxSymbolValue)
+{
+ nodeElt* const huffNode0 = huffNode - 1;
+ int nonNullRank;
+ 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--;
+ lowS = nonNullRank; nodeRoot = nodeNb + lowS - 1; lowN = nodeNb;
+ huffNode[nodeNb].count = huffNode[lowS].count + huffNode[lowS-1].count;
+ huffNode[lowS].parent = huffNode[lowS-1].parent = (U16)nodeNb;
+ nodeNb++; lowS-=2;
+ for (n=nodeNb; n<=nodeRoot; n++) huffNode[n].count = (U32)(1U<<30);
+ huffNode0[0].count = (U32)(1U<<31); /* fake entry, strong barrier */
+
+ /* create parents */
+ while (nodeNb <= nodeRoot) {
+ int const n1 = (huffNode[lowS].count < huffNode[lowN].count) ? lowS-- : lowN++;
+ int const n2 = (huffNode[lowS].count < huffNode[lowN].count) ? lowS-- : lowN++;
+ huffNode[nodeNb].count = huffNode[n1].count + huffNode[n2].count;
+ huffNode[n1].parent = huffNode[n2].parent = (U16)nodeNb;
+ nodeNb++;
+ }
+
+ /* distribute weights (unlimited tree height) */
+ huffNode[nodeRoot].nbBits = 0;
+ for (n=nodeRoot-1; n>=STARTNODE; n--)
+ huffNode[n].nbBits = huffNode[ huffNode[n].parent ].nbBits + 1;
+ 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;
+}
+
+/**
+ * HUF_buildCTableFromTree():
+ * Build the CTable given the Huffman tree in huffNode.
+ *
+ * @param[out] CTable The output Huffman CTable.
+ * @param huffNode The Huffman tree.
+ * @param nonNullRank The last and smallest node in the Huffman tree.
+ * @param maxSymbolValue The maximum symbol value.
+ * @param maxNbBits The exact maximum number of bits used in the Huffman tree.
+ */
+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};
+ U16 valPerRank[HUF_TABLELOG_MAX+1] = {0};
+ int const alphabetSize = (int)(maxSymbolValue + 1);
+ for (n=0; n<=nonNullRank; n++)
+ nbPerRank[huffNode[n].nbBits]++;
+ /* determine starting value per rank */
+ { U16 min = 0;
+ for (n=(int)maxNbBits; n>0; n--) {
+ valPerRank[n] = min; /* get starting value within each rank */
+ min += nbPerRank[n];
+ min >>= 1;
+ } }
+ for (n=0; n<alphabetSize; n++)
+ HUF_setNbBits(ct + huffNode[n].byte, huffNode[n].nbBits); /* push nbBits per symbol, symbol order */
+ for (n=0; n<alphabetSize; n++)
+ HUF_setValue(ct + n, valPerRank[HUF_getNbBits(ct[n])]++); /* assign value within rank, symbol order */
+ CTable[0] = maxNbBits;
+}
+
+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*)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 (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);
+ 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);
+
+ /* 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(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 += HUF_getNbBits(ct[s]) * count[s];
+ }
+ return nbBits >> 3;
+}
+
+int HUF_validateCTable(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue) {
+ HUF_CElt const* ct = CTable + 1;
+ int bad = 0;
+ int s;
+ 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(HUF_CStream_t* bitCPtr, U32 symbol, const HUF_CElt* CTable, int idx, int fast)
+{
+ HUF_addBits(bitCPtr, CTable[symbol], idx, fast);
+}
+
+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);
+
+ /* 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;
+}
+
+
+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 = (U32)CTable[0];
+ 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;
+ HUF_CStream_t bitC;
+
+ /* init */
+ if (dstSize < 8) return 0; /* not enough space to compress */
+ { size_t const initErr = HUF_initCStream(&bitC, op, (size_t)(oend-op));
+ if (HUF_isError(initErr)) return 0; }
+
+ 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 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)
+{
+ return HUF_compress1X_usingCTable_internal_body(dst, dstSize, src, srcSize, CTable);
+}
+
+static size_t
+HUF_compress1X_usingCTable_internal_default(void* dst, size_t dstSize,
+ const void* src, size_t srcSize,
+ const HUF_CElt* CTable)
+{
+ return HUF_compress1X_usingCTable_internal_body(dst, dstSize, src, srcSize, CTable);
+}
+
+static size_t
+HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize,
+ const void* src, size_t srcSize,
+ const HUF_CElt* CTable, const int flags)
+{
+ 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);
+}
+
+#else
+
+static size_t
+HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize,
+ const void* src, size_t srcSize,
+ const HUF_CElt* CTable, const int flags)
+{
+ (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, int flags)
+{
+ 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 flags)
+{
+ size_t const segmentSize = (srcSize+3)/4; /* first 3 segments */
+ const BYTE* ip = (const BYTE*) src;
+ const BYTE* const iend = ip + srcSize;
+ BYTE* const ostart = (BYTE*) dst;
+ BYTE* const oend = ostart + dstSize;
+ BYTE* op = ostart;
+
+ if (dstSize < 6 + 1 + 1 + 1 + 8) return 0; /* minimum space to compress successfully */
+ if (srcSize < 12) return 0; /* no saving possible : too small input */
+ op += 6; /* jumpTable */
+
+ assert(op <= oend);
+ { 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, 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, flags) );
+ if (cSize == 0 || cSize > 65535) return 0;
+ MEM_writeLE16(ostart+4, (U16)cSize);
+ op += cSize;
+ }
+
+ 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, 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, int flags)
+{
+ return HUF_compress4X_usingCTable_internal(dst, dstSize, src, srcSize, CTable, flags);
+}
+
+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 flags)
+{
+ size_t const cSize = (nbStreams==HUF_singleStream) ?
+ 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;
+ /* check compressibility */
+ assert(op >= ostart);
+ if ((size_t)(op-ostart) >= srcSize-1) { return 0; }
+ return (size_t)(op-ostart);
+}
+
+typedef struct {
+ unsigned count[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 maxBits, 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);
+ 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_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, size_t wkspSize,
+ HUF_CElt* oldHufTable, HUF_repeat* repeat, int flags)
+{
+ 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;
+
+ DEBUGLOG(5, "HUF_compress_internal (srcSize=%zu)", srcSize);
+ HUF_STATIC_ASSERT(sizeof(*table) + HUF_WORKSPACE_MAX_ALIGNMENT <= HUF_WORKSPACE_SIZE);
+
+ /* checks & inits */
+ 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 */
+ if (huffLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
+ if (maxSymbolValue > HUF_SYMBOLVALUE_MAX) return ERROR(maxSymbolValue_tooLarge);
+ if (!maxSymbolValue) maxSymbolValue = HUF_SYMBOLVALUE_MAX;
+ if (!huffLog) huffLog = HUF_TABLELOG_DEFAULT;
+
+ /* Heuristic : If old table is valid, use it for small inputs */
+ if ((flags & HUF_flags_preferRepeat) && repeat && *repeat == HUF_repeat_valid) {
+ return HUF_compressCTable_internal(ostart, op, oend,
+ src, srcSize,
+ 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, 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
+ && *repeat == HUF_repeat_check
+ && !HUF_validateCTable(oldHufTable, table->count, maxSymbolValue)) {
+ *repeat = HUF_repeat_none;
+ }
+ /* Heuristic : use existing table for small inputs */
+ if ((flags & HUF_flags_preferRepeat) && repeat && *repeat != HUF_repeat_none) {
+ return HUF_compressCTable_internal(ostart, op, oend,
+ src, srcSize,
+ nbStreams, oldHufTable, flags);
+ }
+
+ /* Build Huffman Tree */
+ 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;
+ DEBUGLOG(6, "bit distribution completed (%zu symbols)", showCTableBits(table->CTable + 1, maxSymbolValue+1));
+ }
+ /* Zero unused symbols in CTable, so we can check it for validity */
+ {
+ size_t const ctableSize = HUF_CTABLE_SIZE_ST(maxSymbolValue);
+ size_t const unusedSize = sizeof(table->CTable) - ctableSize * sizeof(HUF_CElt);
+ ZSTD_memset(table->CTable + ctableSize, 0, unusedSize);
+ }
+
+ /* Write table description header */
+ { CHECK_V_F(hSize, HUF_writeCTable_wksp(op, dstSize, table->CTable, maxSymbolValue, huffLog,
+ &table->wksps.writeCTable_wksp, sizeof(table->wksps.writeCTable_wksp)) );
+ /* Check if using previous huffman table is beneficial */
+ if (repeat && *repeat != HUF_repeat_none) {
+ size_t const oldSize = HUF_estimateCompressedSize(oldHufTable, table->count, maxSymbolValue);
+ size_t const newSize = HUF_estimateCompressedSize(table->CTable, table->count, maxSymbolValue);
+ if (oldSize <= hSize + newSize || hSize + 12 >= srcSize) {
+ return HUF_compressCTable_internal(ostart, op, oend,
+ src, srcSize,
+ nbStreams, oldHufTable, flags);
+ } }
+
+ /* Use the new huffman table */
+ if (hSize + 12ul >= srcSize) { return 0; }
+ op += hSize;
+ if (repeat) { *repeat = HUF_repeat_none; }
+ if (oldHufTable)
+ ZSTD_memcpy(oldHufTable, table->CTable, sizeof(table->CTable)); /* Save new table */
+ }
+ return HUF_compressCTable_internal(ostart, op, oend,
+ src, srcSize,
+ 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 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, flags);
+}
+
+/* HUF_compress4X_repeat():
+ * compress input using 4 streams.
+ * consider skipping quickly
+ * re-use 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 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, flags);
+}
notaz.gp2x.de / pcsx_rearmed.git / blobdiff