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-rw-r--r--lib/zstd/compress/zstd_compress_internal.h1188
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diff --git a/lib/zstd/compress/zstd_compress_internal.h b/lib/zstd/compress/zstd_compress_internal.h
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--- /dev/null
+++ b/lib/zstd/compress/zstd_compress_internal.h
@@ -0,0 +1,1188 @@
+/*
+ * Copyright (c) Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+/* This header contains definitions
+ * that shall **only** be used by modules within lib/compress.
+ */
+
+#ifndef ZSTD_COMPRESS_H
+#define ZSTD_COMPRESS_H
+
+/*-*************************************
+* Dependencies
+***************************************/
+#include "../common/zstd_internal.h"
+#include "zstd_cwksp.h"
+
+
+/*-*************************************
+* Constants
+***************************************/
+#define kSearchStrength 8
+#define HASH_READ_SIZE 8
+#define ZSTD_DUBT_UNSORTED_MARK 1 /* For btlazy2 strategy, index ZSTD_DUBT_UNSORTED_MARK==1 means "unsorted".
+ It could be confused for a real successor at index "1", if sorted as larger than its predecessor.
+ It's not a big deal though : candidate will just be sorted again.
+ Additionally, candidate position 1 will be lost.
+ But candidate 1 cannot hide a large tree of candidates, so it's a minimal loss.
+ The benefit is that ZSTD_DUBT_UNSORTED_MARK cannot be mishandled after table re-use with a different strategy.
+ This constant is required by ZSTD_compressBlock_btlazy2() and ZSTD_reduceTable_internal() */
+
+
+/*-*************************************
+* Context memory management
+***************************************/
+typedef enum { ZSTDcs_created=0, ZSTDcs_init, ZSTDcs_ongoing, ZSTDcs_ending } ZSTD_compressionStage_e;
+typedef enum { zcss_init=0, zcss_load, zcss_flush } ZSTD_cStreamStage;
+
+typedef struct ZSTD_prefixDict_s {
+ const void* dict;
+ size_t dictSize;
+ ZSTD_dictContentType_e dictContentType;
+} ZSTD_prefixDict;
+
+typedef struct {
+ void* dictBuffer;
+ void const* dict;
+ size_t dictSize;
+ ZSTD_dictContentType_e dictContentType;
+ ZSTD_CDict* cdict;
+} ZSTD_localDict;
+
+typedef struct {
+ HUF_CElt CTable[HUF_CTABLE_SIZE_U32(255)];
+ HUF_repeat repeatMode;
+} ZSTD_hufCTables_t;
+
+typedef struct {
+ FSE_CTable offcodeCTable[FSE_CTABLE_SIZE_U32(OffFSELog, MaxOff)];
+ FSE_CTable matchlengthCTable[FSE_CTABLE_SIZE_U32(MLFSELog, MaxML)];
+ FSE_CTable litlengthCTable[FSE_CTABLE_SIZE_U32(LLFSELog, MaxLL)];
+ FSE_repeat offcode_repeatMode;
+ FSE_repeat matchlength_repeatMode;
+ FSE_repeat litlength_repeatMode;
+} ZSTD_fseCTables_t;
+
+typedef struct {
+ ZSTD_hufCTables_t huf;
+ ZSTD_fseCTables_t fse;
+} ZSTD_entropyCTables_t;
+
+typedef struct {
+ U32 off; /* Offset code (offset + ZSTD_REP_MOVE) for the match */
+ U32 len; /* Raw length of match */
+} ZSTD_match_t;
+
+typedef struct {
+ U32 offset; /* Offset of sequence */
+ U32 litLength; /* Length of literals prior to match */
+ U32 matchLength; /* Raw length of match */
+} rawSeq;
+
+typedef struct {
+ rawSeq* seq; /* The start of the sequences */
+ size_t pos; /* The index in seq where reading stopped. pos <= size. */
+ size_t posInSequence; /* The position within the sequence at seq[pos] where reading
+ stopped. posInSequence <= seq[pos].litLength + seq[pos].matchLength */
+ size_t size; /* The number of sequences. <= capacity. */
+ size_t capacity; /* The capacity starting from `seq` pointer */
+} rawSeqStore_t;
+
+UNUSED_ATTR static const rawSeqStore_t kNullRawSeqStore = {NULL, 0, 0, 0, 0};
+
+typedef struct {
+ int price;
+ U32 off;
+ U32 mlen;
+ U32 litlen;
+ U32 rep[ZSTD_REP_NUM];
+} ZSTD_optimal_t;
+
+typedef enum { zop_dynamic=0, zop_predef } ZSTD_OptPrice_e;
+
+typedef struct {
+ /* All tables are allocated inside cctx->workspace by ZSTD_resetCCtx_internal() */
+ unsigned* litFreq; /* table of literals statistics, of size 256 */
+ unsigned* litLengthFreq; /* table of litLength statistics, of size (MaxLL+1) */
+ unsigned* matchLengthFreq; /* table of matchLength statistics, of size (MaxML+1) */
+ unsigned* offCodeFreq; /* table of offCode statistics, of size (MaxOff+1) */
+ ZSTD_match_t* matchTable; /* list of found matches, of size ZSTD_OPT_NUM+1 */
+ ZSTD_optimal_t* priceTable; /* All positions tracked by optimal parser, of size ZSTD_OPT_NUM+1 */
+
+ U32 litSum; /* nb of literals */
+ U32 litLengthSum; /* nb of litLength codes */
+ U32 matchLengthSum; /* nb of matchLength codes */
+ U32 offCodeSum; /* nb of offset codes */
+ U32 litSumBasePrice; /* to compare to log2(litfreq) */
+ U32 litLengthSumBasePrice; /* to compare to log2(llfreq) */
+ U32 matchLengthSumBasePrice;/* to compare to log2(mlfreq) */
+ U32 offCodeSumBasePrice; /* to compare to log2(offreq) */
+ ZSTD_OptPrice_e priceType; /* prices can be determined dynamically, or follow a pre-defined cost structure */
+ const ZSTD_entropyCTables_t* symbolCosts; /* pre-calculated dictionary statistics */
+ ZSTD_literalCompressionMode_e literalCompressionMode;
+} optState_t;
+
+typedef struct {
+ ZSTD_entropyCTables_t entropy;
+ U32 rep[ZSTD_REP_NUM];
+} ZSTD_compressedBlockState_t;
+
+typedef struct {
+ BYTE const* nextSrc; /* next block here to continue on current prefix */
+ BYTE const* base; /* All regular indexes relative to this position */
+ BYTE const* dictBase; /* extDict indexes relative to this position */
+ U32 dictLimit; /* below that point, need extDict */
+ U32 lowLimit; /* below that point, no more valid data */
+} ZSTD_window_t;
+
+typedef struct ZSTD_matchState_t ZSTD_matchState_t;
+struct ZSTD_matchState_t {
+ ZSTD_window_t window; /* State for window round buffer management */
+ U32 loadedDictEnd; /* index of end of dictionary, within context's referential.
+ * When loadedDictEnd != 0, a dictionary is in use, and still valid.
+ * This relies on a mechanism to set loadedDictEnd=0 when dictionary is no longer within distance.
+ * Such mechanism is provided within ZSTD_window_enforceMaxDist() and ZSTD_checkDictValidity().
+ * When dict referential is copied into active context (i.e. not attached),
+ * loadedDictEnd == dictSize, since referential starts from zero.
+ */
+ U32 nextToUpdate; /* index from which to continue table update */
+ U32 hashLog3; /* dispatch table for matches of len==3 : larger == faster, more memory */
+ U32* hashTable;
+ U32* hashTable3;
+ U32* chainTable;
+ int dedicatedDictSearch; /* Indicates whether this matchState is using the
+ * dedicated dictionary search structure.
+ */
+ optState_t opt; /* optimal parser state */
+ const ZSTD_matchState_t* dictMatchState;
+ ZSTD_compressionParameters cParams;
+ const rawSeqStore_t* ldmSeqStore;
+};
+
+typedef struct {
+ ZSTD_compressedBlockState_t* prevCBlock;
+ ZSTD_compressedBlockState_t* nextCBlock;
+ ZSTD_matchState_t matchState;
+} ZSTD_blockState_t;
+
+typedef struct {
+ U32 offset;
+ U32 checksum;
+} ldmEntry_t;
+
+typedef struct {
+ BYTE const* split;
+ U32 hash;
+ U32 checksum;
+ ldmEntry_t* bucket;
+} ldmMatchCandidate_t;
+
+#define LDM_BATCH_SIZE 64
+
+typedef struct {
+ ZSTD_window_t window; /* State for the window round buffer management */
+ ldmEntry_t* hashTable;
+ U32 loadedDictEnd;
+ BYTE* bucketOffsets; /* Next position in bucket to insert entry */
+ size_t splitIndices[LDM_BATCH_SIZE];
+ ldmMatchCandidate_t matchCandidates[LDM_BATCH_SIZE];
+} ldmState_t;
+
+typedef struct {
+ U32 enableLdm; /* 1 if enable long distance matching */
+ U32 hashLog; /* Log size of hashTable */
+ U32 bucketSizeLog; /* Log bucket size for collision resolution, at most 8 */
+ U32 minMatchLength; /* Minimum match length */
+ U32 hashRateLog; /* Log number of entries to skip */
+ U32 windowLog; /* Window log for the LDM */
+} ldmParams_t;
+
+typedef struct {
+ int collectSequences;
+ ZSTD_Sequence* seqStart;
+ size_t seqIndex;
+ size_t maxSequences;
+} SeqCollector;
+
+struct ZSTD_CCtx_params_s {
+ ZSTD_format_e format;
+ ZSTD_compressionParameters cParams;
+ ZSTD_frameParameters fParams;
+
+ int compressionLevel;
+ int forceWindow; /* force back-references to respect limit of
+ * 1<<wLog, even for dictionary */
+ size_t targetCBlockSize; /* Tries to fit compressed block size to be around targetCBlockSize.
+ * No target when targetCBlockSize == 0.
+ * There is no guarantee on compressed block size */
+ int srcSizeHint; /* User's best guess of source size.
+ * Hint is not valid when srcSizeHint == 0.
+ * There is no guarantee that hint is close to actual source size */
+
+ ZSTD_dictAttachPref_e attachDictPref;
+ ZSTD_literalCompressionMode_e literalCompressionMode;
+
+ /* Multithreading: used to pass parameters to mtctx */
+ int nbWorkers;
+ size_t jobSize;
+ int overlapLog;
+ int rsyncable;
+
+ /* Long distance matching parameters */
+ ldmParams_t ldmParams;
+
+ /* Dedicated dict search algorithm trigger */
+ int enableDedicatedDictSearch;
+
+ /* Input/output buffer modes */
+ ZSTD_bufferMode_e inBufferMode;
+ ZSTD_bufferMode_e outBufferMode;
+
+ /* Sequence compression API */
+ ZSTD_sequenceFormat_e blockDelimiters;
+ int validateSequences;
+
+ /* Internal use, for createCCtxParams() and freeCCtxParams() only */
+ ZSTD_customMem customMem;
+}; /* typedef'd to ZSTD_CCtx_params within "zstd.h" */
+
+#define COMPRESS_SEQUENCES_WORKSPACE_SIZE (sizeof(unsigned) * (MaxSeq + 2))
+#define ENTROPY_WORKSPACE_SIZE (HUF_WORKSPACE_SIZE + COMPRESS_SEQUENCES_WORKSPACE_SIZE)
+
+/*
+ * Indicates whether this compression proceeds directly from user-provided
+ * source buffer to user-provided destination buffer (ZSTDb_not_buffered), or
+ * whether the context needs to buffer the input/output (ZSTDb_buffered).
+ */
+typedef enum {
+ ZSTDb_not_buffered,
+ ZSTDb_buffered
+} ZSTD_buffered_policy_e;
+
+struct ZSTD_CCtx_s {
+ ZSTD_compressionStage_e stage;
+ int cParamsChanged; /* == 1 if cParams(except wlog) or compression level are changed in requestedParams. Triggers transmission of new params to ZSTDMT (if available) then reset to 0. */
+ int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
+ ZSTD_CCtx_params requestedParams;
+ ZSTD_CCtx_params appliedParams;
+ U32 dictID;
+ size_t dictContentSize;
+
+ ZSTD_cwksp workspace; /* manages buffer for dynamic allocations */
+ size_t blockSize;
+ unsigned long long pledgedSrcSizePlusOne; /* this way, 0 (default) == unknown */
+ unsigned long long consumedSrcSize;
+ unsigned long long producedCSize;
+ struct xxh64_state xxhState;
+ ZSTD_customMem customMem;
+ ZSTD_threadPool* pool;
+ size_t staticSize;
+ SeqCollector seqCollector;
+ int isFirstBlock;
+ int initialized;
+
+ seqStore_t seqStore; /* sequences storage ptrs */
+ ldmState_t ldmState; /* long distance matching state */
+ rawSeq* ldmSequences; /* Storage for the ldm output sequences */
+ size_t maxNbLdmSequences;
+ rawSeqStore_t externSeqStore; /* Mutable reference to external sequences */
+ ZSTD_blockState_t blockState;
+ U32* entropyWorkspace; /* entropy workspace of ENTROPY_WORKSPACE_SIZE bytes */
+
+ /* Wether we are streaming or not */
+ ZSTD_buffered_policy_e bufferedPolicy;
+
+ /* streaming */
+ char* inBuff;
+ size_t inBuffSize;
+ size_t inToCompress;
+ size_t inBuffPos;
+ size_t inBuffTarget;
+ char* outBuff;
+ size_t outBuffSize;
+ size_t outBuffContentSize;
+ size_t outBuffFlushedSize;
+ ZSTD_cStreamStage streamStage;
+ U32 frameEnded;
+
+ /* Stable in/out buffer verification */
+ ZSTD_inBuffer expectedInBuffer;
+ size_t expectedOutBufferSize;
+
+ /* Dictionary */
+ ZSTD_localDict localDict;
+ const ZSTD_CDict* cdict;
+ ZSTD_prefixDict prefixDict; /* single-usage dictionary */
+
+ /* Multi-threading */
+
+ /* Tracing */
+};
+
+typedef enum { ZSTD_dtlm_fast, ZSTD_dtlm_full } ZSTD_dictTableLoadMethod_e;
+
+typedef enum {
+ ZSTD_noDict = 0,
+ ZSTD_extDict = 1,
+ ZSTD_dictMatchState = 2,
+ ZSTD_dedicatedDictSearch = 3
+} ZSTD_dictMode_e;
+
+typedef enum {
+ ZSTD_cpm_noAttachDict = 0, /* Compression with ZSTD_noDict or ZSTD_extDict.
+ * In this mode we use both the srcSize and the dictSize
+ * when selecting and adjusting parameters.
+ */
+ ZSTD_cpm_attachDict = 1, /* Compression with ZSTD_dictMatchState or ZSTD_dedicatedDictSearch.
+ * In this mode we only take the srcSize into account when selecting
+ * and adjusting parameters.
+ */
+ ZSTD_cpm_createCDict = 2, /* Creating a CDict.
+ * In this mode we take both the source size and the dictionary size
+ * into account when selecting and adjusting the parameters.
+ */
+ ZSTD_cpm_unknown = 3, /* ZSTD_getCParams, ZSTD_getParams, ZSTD_adjustParams.
+ * We don't know what these parameters are for. We default to the legacy
+ * behavior of taking both the source size and the dict size into account
+ * when selecting and adjusting parameters.
+ */
+} ZSTD_cParamMode_e;
+
+typedef size_t (*ZSTD_blockCompressor) (
+ ZSTD_matchState_t* bs, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
+ void const* src, size_t srcSize);
+ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, ZSTD_dictMode_e dictMode);
+
+
+MEM_STATIC U32 ZSTD_LLcode(U32 litLength)
+{
+ static const BYTE LL_Code[64] = { 0, 1, 2, 3, 4, 5, 6, 7,
+ 8, 9, 10, 11, 12, 13, 14, 15,
+ 16, 16, 17, 17, 18, 18, 19, 19,
+ 20, 20, 20, 20, 21, 21, 21, 21,
+ 22, 22, 22, 22, 22, 22, 22, 22,
+ 23, 23, 23, 23, 23, 23, 23, 23,
+ 24, 24, 24, 24, 24, 24, 24, 24,
+ 24, 24, 24, 24, 24, 24, 24, 24 };
+ static const U32 LL_deltaCode = 19;
+ return (litLength > 63) ? ZSTD_highbit32(litLength) + LL_deltaCode : LL_Code[litLength];
+}
+
+/* ZSTD_MLcode() :
+ * note : mlBase = matchLength - MINMATCH;
+ * because it's the format it's stored in seqStore->sequences */
+MEM_STATIC U32 ZSTD_MLcode(U32 mlBase)
+{
+ static const BYTE ML_Code[128] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
+ 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
+ 32, 32, 33, 33, 34, 34, 35, 35, 36, 36, 36, 36, 37, 37, 37, 37,
+ 38, 38, 38, 38, 38, 38, 38, 38, 39, 39, 39, 39, 39, 39, 39, 39,
+ 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,
+ 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41,
+ 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42,
+ 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42 };
+ static const U32 ML_deltaCode = 36;
+ return (mlBase > 127) ? ZSTD_highbit32(mlBase) + ML_deltaCode : ML_Code[mlBase];
+}
+
+typedef struct repcodes_s {
+ U32 rep[3];
+} repcodes_t;
+
+MEM_STATIC repcodes_t ZSTD_updateRep(U32 const rep[3], U32 const offset, U32 const ll0)
+{
+ repcodes_t newReps;
+ if (offset >= ZSTD_REP_NUM) { /* full offset */
+ newReps.rep[2] = rep[1];
+ newReps.rep[1] = rep[0];
+ newReps.rep[0] = offset - ZSTD_REP_MOVE;
+ } else { /* repcode */
+ U32 const repCode = offset + ll0;
+ if (repCode > 0) { /* note : if repCode==0, no change */
+ U32 const currentOffset = (repCode==ZSTD_REP_NUM) ? (rep[0] - 1) : rep[repCode];
+ newReps.rep[2] = (repCode >= 2) ? rep[1] : rep[2];
+ newReps.rep[1] = rep[0];
+ newReps.rep[0] = currentOffset;
+ } else { /* repCode == 0 */
+ ZSTD_memcpy(&newReps, rep, sizeof(newReps));
+ }
+ }
+ return newReps;
+}
+
+/* ZSTD_cParam_withinBounds:
+ * @return 1 if value is within cParam bounds,
+ * 0 otherwise */
+MEM_STATIC int ZSTD_cParam_withinBounds(ZSTD_cParameter cParam, int value)
+{
+ ZSTD_bounds const bounds = ZSTD_cParam_getBounds(cParam);
+ if (ZSTD_isError(bounds.error)) return 0;
+ if (value < bounds.lowerBound) return 0;
+ if (value > bounds.upperBound) return 0;
+ return 1;
+}
+
+/* ZSTD_noCompressBlock() :
+ * Writes uncompressed block to dst buffer from given src.
+ * Returns the size of the block */
+MEM_STATIC size_t ZSTD_noCompressBlock (void* dst, size_t dstCapacity, const void* src, size_t srcSize, U32 lastBlock)
+{
+ U32 const cBlockHeader24 = lastBlock + (((U32)bt_raw)<<1) + (U32)(srcSize << 3);
+ RETURN_ERROR_IF(srcSize + ZSTD_blockHeaderSize > dstCapacity,
+ dstSize_tooSmall, "dst buf too small for uncompressed block");
+ MEM_writeLE24(dst, cBlockHeader24);
+ ZSTD_memcpy((BYTE*)dst + ZSTD_blockHeaderSize, src, srcSize);
+ return ZSTD_blockHeaderSize + srcSize;
+}
+
+MEM_STATIC size_t ZSTD_rleCompressBlock (void* dst, size_t dstCapacity, BYTE src, size_t srcSize, U32 lastBlock)
+{
+ BYTE* const op = (BYTE*)dst;
+ U32 const cBlockHeader = lastBlock + (((U32)bt_rle)<<1) + (U32)(srcSize << 3);
+ RETURN_ERROR_IF(dstCapacity < 4, dstSize_tooSmall, "");
+ MEM_writeLE24(op, cBlockHeader);
+ op[3] = src;
+ return 4;
+}
+
+
+/* ZSTD_minGain() :
+ * minimum compression required
+ * to generate a compress block or a compressed literals section.
+ * note : use same formula for both situations */
+MEM_STATIC size_t ZSTD_minGain(size_t srcSize, ZSTD_strategy strat)
+{
+ U32 const minlog = (strat>=ZSTD_btultra) ? (U32)(strat) - 1 : 6;
+ ZSTD_STATIC_ASSERT(ZSTD_btultra == 8);
+ assert(ZSTD_cParam_withinBounds(ZSTD_c_strategy, strat));
+ return (srcSize >> minlog) + 2;
+}
+
+MEM_STATIC int ZSTD_disableLiteralsCompression(const ZSTD_CCtx_params* cctxParams)
+{
+ switch (cctxParams->literalCompressionMode) {
+ case ZSTD_lcm_huffman:
+ return 0;
+ case ZSTD_lcm_uncompressed:
+ return 1;
+ default:
+ assert(0 /* impossible: pre-validated */);
+ ZSTD_FALLTHROUGH;
+ case ZSTD_lcm_auto:
+ return (cctxParams->cParams.strategy == ZSTD_fast) && (cctxParams->cParams.targetLength > 0);
+ }
+}
+
+/*! ZSTD_safecopyLiterals() :
+ * memcpy() function that won't read beyond more than WILDCOPY_OVERLENGTH bytes past ilimit_w.
+ * Only called when the sequence ends past ilimit_w, so it only needs to be optimized for single
+ * large copies.
+ */
+static void ZSTD_safecopyLiterals(BYTE* op, BYTE const* ip, BYTE const* const iend, BYTE const* ilimit_w) {
+ assert(iend > ilimit_w);
+ if (ip <= ilimit_w) {
+ ZSTD_wildcopy(op, ip, ilimit_w - ip, ZSTD_no_overlap);
+ op += ilimit_w - ip;
+ ip = ilimit_w;
+ }
+ while (ip < iend) *op++ = *ip++;
+}
+
+/*! ZSTD_storeSeq() :
+ * Store a sequence (litlen, litPtr, offCode and mlBase) into seqStore_t.
+ * `offCode` : distance to match + ZSTD_REP_MOVE (values <= ZSTD_REP_MOVE are repCodes).
+ * `mlBase` : matchLength - MINMATCH
+ * Allowed to overread literals up to litLimit.
+*/
+HINT_INLINE UNUSED_ATTR
+void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* literals, const BYTE* litLimit, U32 offCode, size_t mlBase)
+{
+ BYTE const* const litLimit_w = litLimit - WILDCOPY_OVERLENGTH;
+ BYTE const* const litEnd = literals + litLength;
+#if defined(DEBUGLEVEL) && (DEBUGLEVEL >= 6)
+ static const BYTE* g_start = NULL;
+ if (g_start==NULL) g_start = (const BYTE*)literals; /* note : index only works for compression within a single segment */
+ { U32 const pos = (U32)((const BYTE*)literals - g_start);
+ DEBUGLOG(6, "Cpos%7u :%3u literals, match%4u bytes at offCode%7u",
+ pos, (U32)litLength, (U32)mlBase+MINMATCH, (U32)offCode);
+ }
+#endif
+ assert((size_t)(seqStorePtr->sequences - seqStorePtr->sequencesStart) < seqStorePtr->maxNbSeq);
+ /* copy Literals */
+ assert(seqStorePtr->maxNbLit <= 128 KB);
+ assert(seqStorePtr->lit + litLength <= seqStorePtr->litStart + seqStorePtr->maxNbLit);
+ assert(literals + litLength <= litLimit);
+ if (litEnd <= litLimit_w) {
+ /* Common case we can use wildcopy.
+ * First copy 16 bytes, because literals are likely short.
+ */
+ assert(WILDCOPY_OVERLENGTH >= 16);
+ ZSTD_copy16(seqStorePtr->lit, literals);
+ if (litLength > 16) {
+ ZSTD_wildcopy(seqStorePtr->lit+16, literals+16, (ptrdiff_t)litLength-16, ZSTD_no_overlap);
+ }
+ } else {
+ ZSTD_safecopyLiterals(seqStorePtr->lit, literals, litEnd, litLimit_w);
+ }
+ seqStorePtr->lit += litLength;
+
+ /* literal Length */
+ if (litLength>0xFFFF) {
+ assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */
+ seqStorePtr->longLengthID = 1;
+ seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
+ }
+ seqStorePtr->sequences[0].litLength = (U16)litLength;
+
+ /* match offset */
+ seqStorePtr->sequences[0].offset = offCode + 1;
+
+ /* match Length */
+ if (mlBase>0xFFFF) {
+ assert(seqStorePtr->longLengthID == 0); /* there can only be a single long length */
+ seqStorePtr->longLengthID = 2;
+ seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
+ }
+ seqStorePtr->sequences[0].matchLength = (U16)mlBase;
+
+ seqStorePtr->sequences++;
+}
+
+
+/*-*************************************
+* Match length counter
+***************************************/
+static unsigned ZSTD_NbCommonBytes (size_t val)
+{
+ if (MEM_isLittleEndian()) {
+ if (MEM_64bits()) {
+# if (__GNUC__ >= 4)
+ return (__builtin_ctzll((U64)val) >> 3);
+# else
+ static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2,
+ 0, 3, 1, 3, 1, 4, 2, 7,
+ 0, 2, 3, 6, 1, 5, 3, 5,
+ 1, 3, 4, 4, 2, 5, 6, 7,
+ 7, 0, 1, 2, 3, 3, 4, 6,
+ 2, 6, 5, 5, 3, 4, 5, 6,
+ 7, 1, 2, 4, 6, 4, 4, 5,
+ 7, 2, 6, 5, 7, 6, 7, 7 };
+ return DeBruijnBytePos[((U64)((val & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58];
+# endif
+ } else { /* 32 bits */
+# if (__GNUC__ >= 3)
+ return (__builtin_ctz((U32)val) >> 3);
+# else
+ static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0,
+ 3, 2, 2, 1, 3, 2, 0, 1,
+ 3, 3, 1, 2, 2, 2, 2, 0,
+ 3, 1, 2, 0, 1, 0, 1, 1 };
+ return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
+# endif
+ }
+ } else { /* Big Endian CPU */
+ if (MEM_64bits()) {
+# if (__GNUC__ >= 4)
+ return (__builtin_clzll(val) >> 3);
+# else
+ unsigned r;
+ const unsigned n32 = sizeof(size_t)*4; /* calculate this way due to compiler complaining in 32-bits mode */
+ if (!(val>>n32)) { r=4; } else { r=0; val>>=n32; }
+ if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
+ r += (!val);
+ return r;
+# endif
+ } else { /* 32 bits */
+# if (__GNUC__ >= 3)
+ return (__builtin_clz((U32)val) >> 3);
+# else
+ unsigned r;
+ if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
+ r += (!val);
+ return r;
+# endif
+ } }
+}
+
+
+MEM_STATIC size_t ZSTD_count(const BYTE* pIn, const BYTE* pMatch, const BYTE* const pInLimit)
+{
+ const BYTE* const pStart = pIn;
+ const BYTE* const pInLoopLimit = pInLimit - (sizeof(size_t)-1);
+
+ if (pIn < pInLoopLimit) {
+ { size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn);
+ if (diff) return ZSTD_NbCommonBytes(diff); }
+ pIn+=sizeof(size_t); pMatch+=sizeof(size_t);
+ while (pIn < pInLoopLimit) {
+ size_t const diff = MEM_readST(pMatch) ^ MEM_readST(pIn);
+ if (!diff) { pIn+=sizeof(size_t); pMatch+=sizeof(size_t); continue; }
+ pIn += ZSTD_NbCommonBytes(diff);
+ return (size_t)(pIn - pStart);
+ } }
+ if (MEM_64bits() && (pIn<(pInLimit-3)) && (MEM_read32(pMatch) == MEM_read32(pIn))) { pIn+=4; pMatch+=4; }
+ if ((pIn<(pInLimit-1)) && (MEM_read16(pMatch) == MEM_read16(pIn))) { pIn+=2; pMatch+=2; }
+ if ((pIn<pInLimit) && (*pMatch == *pIn)) pIn++;
+ return (size_t)(pIn - pStart);
+}
+
+/* ZSTD_count_2segments() :
+ * can count match length with `ip` & `match` in 2 different segments.
+ * convention : on reaching mEnd, match count continue starting from iStart
+ */
+MEM_STATIC size_t
+ZSTD_count_2segments(const BYTE* ip, const BYTE* match,
+ const BYTE* iEnd, const BYTE* mEnd, const BYTE* iStart)
+{
+ const BYTE* const vEnd = MIN( ip + (mEnd - match), iEnd);
+ size_t const matchLength = ZSTD_count(ip, match, vEnd);
+ if (match + matchLength != mEnd) return matchLength;
+ DEBUGLOG(7, "ZSTD_count_2segments: found a 2-parts match (current length==%zu)", matchLength);
+ DEBUGLOG(7, "distance from match beginning to end dictionary = %zi", mEnd - match);
+ DEBUGLOG(7, "distance from current pos to end buffer = %zi", iEnd - ip);
+ DEBUGLOG(7, "next byte : ip==%02X, istart==%02X", ip[matchLength], *iStart);
+ DEBUGLOG(7, "final match length = %zu", matchLength + ZSTD_count(ip+matchLength, iStart, iEnd));
+ return matchLength + ZSTD_count(ip+matchLength, iStart, iEnd);
+}
+
+
+/*-*************************************
+ * Hashes
+ ***************************************/
+static const U32 prime3bytes = 506832829U;
+static U32 ZSTD_hash3(U32 u, U32 h) { return ((u << (32-24)) * prime3bytes) >> (32-h) ; }
+MEM_STATIC size_t ZSTD_hash3Ptr(const void* ptr, U32 h) { return ZSTD_hash3(MEM_readLE32(ptr), h); } /* only in zstd_opt.h */
+
+static const U32 prime4bytes = 2654435761U;
+static U32 ZSTD_hash4(U32 u, U32 h) { return (u * prime4bytes) >> (32-h) ; }
+static size_t ZSTD_hash4Ptr(const void* ptr, U32 h) { return ZSTD_hash4(MEM_read32(ptr), h); }
+
+static const U64 prime5bytes = 889523592379ULL;
+static size_t ZSTD_hash5(U64 u, U32 h) { return (size_t)(((u << (64-40)) * prime5bytes) >> (64-h)) ; }
+static size_t ZSTD_hash5Ptr(const void* p, U32 h) { return ZSTD_hash5(MEM_readLE64(p), h); }
+
+static const U64 prime6bytes = 227718039650203ULL;
+static size_t ZSTD_hash6(U64 u, U32 h) { return (size_t)(((u << (64-48)) * prime6bytes) >> (64-h)) ; }
+static size_t ZSTD_hash6Ptr(const void* p, U32 h) { return ZSTD_hash6(MEM_readLE64(p), h); }
+
+static const U64 prime7bytes = 58295818150454627ULL;
+static size_t ZSTD_hash7(U64 u, U32 h) { return (size_t)(((u << (64-56)) * prime7bytes) >> (64-h)) ; }
+static size_t ZSTD_hash7Ptr(const void* p, U32 h) { return ZSTD_hash7(MEM_readLE64(p), h); }
+
+static const U64 prime8bytes = 0xCF1BBCDCB7A56463ULL;
+static size_t ZSTD_hash8(U64 u, U32 h) { return (size_t)(((u) * prime8bytes) >> (64-h)) ; }
+static size_t ZSTD_hash8Ptr(const void* p, U32 h) { return ZSTD_hash8(MEM_readLE64(p), h); }
+
+MEM_STATIC FORCE_INLINE_ATTR
+size_t ZSTD_hashPtr(const void* p, U32 hBits, U32 mls)
+{
+ switch(mls)
+ {
+ default:
+ case 4: return ZSTD_hash4Ptr(p, hBits);
+ case 5: return ZSTD_hash5Ptr(p, hBits);
+ case 6: return ZSTD_hash6Ptr(p, hBits);
+ case 7: return ZSTD_hash7Ptr(p, hBits);
+ case 8: return ZSTD_hash8Ptr(p, hBits);
+ }
+}
+
+/* ZSTD_ipow() :
+ * Return base^exponent.
+ */
+static U64 ZSTD_ipow(U64 base, U64 exponent)
+{
+ U64 power = 1;
+ while (exponent) {
+ if (exponent & 1) power *= base;
+ exponent >>= 1;
+ base *= base;
+ }
+ return power;
+}
+
+#define ZSTD_ROLL_HASH_CHAR_OFFSET 10
+
+/* ZSTD_rollingHash_append() :
+ * Add the buffer to the hash value.
+ */
+static U64 ZSTD_rollingHash_append(U64 hash, void const* buf, size_t size)
+{
+ BYTE const* istart = (BYTE const*)buf;
+ size_t pos;
+ for (pos = 0; pos < size; ++pos) {
+ hash *= prime8bytes;
+ hash += istart[pos] + ZSTD_ROLL_HASH_CHAR_OFFSET;
+ }
+ return hash;
+}
+
+/* ZSTD_rollingHash_compute() :
+ * Compute the rolling hash value of the buffer.
+ */
+MEM_STATIC U64 ZSTD_rollingHash_compute(void const* buf, size_t size)
+{
+ return ZSTD_rollingHash_append(0, buf, size);
+}
+
+/* ZSTD_rollingHash_primePower() :
+ * Compute the primePower to be passed to ZSTD_rollingHash_rotate() for a hash
+ * over a window of length bytes.
+ */
+MEM_STATIC U64 ZSTD_rollingHash_primePower(U32 length)
+{
+ return ZSTD_ipow(prime8bytes, length - 1);
+}
+
+/* ZSTD_rollingHash_rotate() :
+ * Rotate the rolling hash by one byte.
+ */
+MEM_STATIC U64 ZSTD_rollingHash_rotate(U64 hash, BYTE toRemove, BYTE toAdd, U64 primePower)
+{
+ hash -= (toRemove + ZSTD_ROLL_HASH_CHAR_OFFSET) * primePower;
+ hash *= prime8bytes;
+ hash += toAdd + ZSTD_ROLL_HASH_CHAR_OFFSET;
+ return hash;
+}
+
+/*-*************************************
+* Round buffer management
+***************************************/
+#if (ZSTD_WINDOWLOG_MAX_64 > 31)
+# error "ZSTD_WINDOWLOG_MAX is too large : would overflow ZSTD_CURRENT_MAX"
+#endif
+/* Max current allowed */
+#define ZSTD_CURRENT_MAX ((3U << 29) + (1U << ZSTD_WINDOWLOG_MAX))
+/* Maximum chunk size before overflow correction needs to be called again */
+#define ZSTD_CHUNKSIZE_MAX \
+ ( ((U32)-1) /* Maximum ending current index */ \
+ - ZSTD_CURRENT_MAX) /* Maximum beginning lowLimit */
+
+/*
+ * ZSTD_window_clear():
+ * Clears the window containing the history by simply setting it to empty.
+ */
+MEM_STATIC void ZSTD_window_clear(ZSTD_window_t* window)
+{
+ size_t const endT = (size_t)(window->nextSrc - window->base);
+ U32 const end = (U32)endT;
+
+ window->lowLimit = end;
+ window->dictLimit = end;
+}
+
+/*
+ * ZSTD_window_hasExtDict():
+ * Returns non-zero if the window has a non-empty extDict.
+ */
+MEM_STATIC U32 ZSTD_window_hasExtDict(ZSTD_window_t const window)
+{
+ return window.lowLimit < window.dictLimit;
+}
+
+/*
+ * ZSTD_matchState_dictMode():
+ * Inspects the provided matchState and figures out what dictMode should be
+ * passed to the compressor.
+ */
+MEM_STATIC ZSTD_dictMode_e ZSTD_matchState_dictMode(const ZSTD_matchState_t *ms)
+{
+ return ZSTD_window_hasExtDict(ms->window) ?
+ ZSTD_extDict :
+ ms->dictMatchState != NULL ?
+ (ms->dictMatchState->dedicatedDictSearch ? ZSTD_dedicatedDictSearch : ZSTD_dictMatchState) :
+ ZSTD_noDict;
+}
+
+/*
+ * ZSTD_window_needOverflowCorrection():
+ * Returns non-zero if the indices are getting too large and need overflow
+ * protection.
+ */
+MEM_STATIC U32 ZSTD_window_needOverflowCorrection(ZSTD_window_t const window,
+ void const* srcEnd)
+{
+ U32 const curr = (U32)((BYTE const*)srcEnd - window.base);
+ return curr > ZSTD_CURRENT_MAX;
+}
+
+/*
+ * ZSTD_window_correctOverflow():
+ * Reduces the indices to protect from index overflow.
+ * Returns the correction made to the indices, which must be applied to every
+ * stored index.
+ *
+ * The least significant cycleLog bits of the indices must remain the same,
+ * which may be 0. Every index up to maxDist in the past must be valid.
+ * NOTE: (maxDist & cycleMask) must be zero.
+ */
+MEM_STATIC U32 ZSTD_window_correctOverflow(ZSTD_window_t* window, U32 cycleLog,
+ U32 maxDist, void const* src)
+{
+ /* preemptive overflow correction:
+ * 1. correction is large enough:
+ * lowLimit > (3<<29) ==> current > 3<<29 + 1<<windowLog
+ * 1<<windowLog <= newCurrent < 1<<chainLog + 1<<windowLog
+ *
+ * current - newCurrent
+ * > (3<<29 + 1<<windowLog) - (1<<windowLog + 1<<chainLog)
+ * > (3<<29) - (1<<chainLog)
+ * > (3<<29) - (1<<30) (NOTE: chainLog <= 30)
+ * > 1<<29
+ *
+ * 2. (ip+ZSTD_CHUNKSIZE_MAX - cctx->base) doesn't overflow:
+ * After correction, current is less than (1<<chainLog + 1<<windowLog).
+ * In 64-bit mode we are safe, because we have 64-bit ptrdiff_t.
+ * In 32-bit mode we are safe, because (chainLog <= 29), so
+ * ip+ZSTD_CHUNKSIZE_MAX - cctx->base < 1<<32.
+ * 3. (cctx->lowLimit + 1<<windowLog) < 1<<32:
+ * windowLog <= 31 ==> 3<<29 + 1<<windowLog < 7<<29 < 1<<32.
+ */
+ U32 const cycleMask = (1U << cycleLog) - 1;
+ U32 const curr = (U32)((BYTE const*)src - window->base);
+ U32 const currentCycle0 = curr & cycleMask;
+ /* Exclude zero so that newCurrent - maxDist >= 1. */
+ U32 const currentCycle1 = currentCycle0 == 0 ? (1U << cycleLog) : currentCycle0;
+ U32 const newCurrent = currentCycle1 + maxDist;
+ U32 const correction = curr - newCurrent;
+ assert((maxDist & cycleMask) == 0);
+ assert(curr > newCurrent);
+ /* Loose bound, should be around 1<<29 (see above) */
+ assert(correction > 1<<28);
+
+ window->base += correction;
+ window->dictBase += correction;
+ if (window->lowLimit <= correction) window->lowLimit = 1;
+ else window->lowLimit -= correction;
+ if (window->dictLimit <= correction) window->dictLimit = 1;
+ else window->dictLimit -= correction;
+
+ /* Ensure we can still reference the full window. */
+ assert(newCurrent >= maxDist);
+ assert(newCurrent - maxDist >= 1);
+ /* Ensure that lowLimit and dictLimit didn't underflow. */
+ assert(window->lowLimit <= newCurrent);
+ assert(window->dictLimit <= newCurrent);
+
+ DEBUGLOG(4, "Correction of 0x%x bytes to lowLimit=0x%x", correction,
+ window->lowLimit);
+ return correction;
+}
+
+/*
+ * ZSTD_window_enforceMaxDist():
+ * Updates lowLimit so that:
+ * (srcEnd - base) - lowLimit == maxDist + loadedDictEnd
+ *
+ * It ensures index is valid as long as index >= lowLimit.
+ * This must be called before a block compression call.
+ *
+ * loadedDictEnd is only defined if a dictionary is in use for current compression.
+ * As the name implies, loadedDictEnd represents the index at end of dictionary.
+ * The value lies within context's referential, it can be directly compared to blockEndIdx.
+ *
+ * If loadedDictEndPtr is NULL, no dictionary is in use, and we use loadedDictEnd == 0.
+ * If loadedDictEndPtr is not NULL, we set it to zero after updating lowLimit.
+ * This is because dictionaries are allowed to be referenced fully
+ * as long as the last byte of the dictionary is in the window.
+ * Once input has progressed beyond window size, dictionary cannot be referenced anymore.
+ *
+ * In normal dict mode, the dictionary lies between lowLimit and dictLimit.
+ * In dictMatchState mode, lowLimit and dictLimit are the same,
+ * and the dictionary is below them.
+ * forceWindow and dictMatchState are therefore incompatible.
+ */
+MEM_STATIC void
+ZSTD_window_enforceMaxDist(ZSTD_window_t* window,
+ const void* blockEnd,
+ U32 maxDist,
+ U32* loadedDictEndPtr,
+ const ZSTD_matchState_t** dictMatchStatePtr)
+{
+ U32 const blockEndIdx = (U32)((BYTE const*)blockEnd - window->base);
+ U32 const loadedDictEnd = (loadedDictEndPtr != NULL) ? *loadedDictEndPtr : 0;
+ DEBUGLOG(5, "ZSTD_window_enforceMaxDist: blockEndIdx=%u, maxDist=%u, loadedDictEnd=%u",
+ (unsigned)blockEndIdx, (unsigned)maxDist, (unsigned)loadedDictEnd);
+
+ /* - When there is no dictionary : loadedDictEnd == 0.
+ In which case, the test (blockEndIdx > maxDist) is merely to avoid
+ overflowing next operation `newLowLimit = blockEndIdx - maxDist`.
+ - When there is a standard dictionary :
+ Index referential is copied from the dictionary,
+ which means it starts from 0.
+ In which case, loadedDictEnd == dictSize,
+ and it makes sense to compare `blockEndIdx > maxDist + dictSize`
+ since `blockEndIdx` also starts from zero.
+ - When there is an attached dictionary :
+ loadedDictEnd is expressed within the referential of the context,
+ so it can be directly compared against blockEndIdx.
+ */
+ if (blockEndIdx > maxDist + loadedDictEnd) {
+ U32 const newLowLimit = blockEndIdx - maxDist;
+ if (window->lowLimit < newLowLimit) window->lowLimit = newLowLimit;
+ if (window->dictLimit < window->lowLimit) {
+ DEBUGLOG(5, "Update dictLimit to match lowLimit, from %u to %u",
+ (unsigned)window->dictLimit, (unsigned)window->lowLimit);
+ window->dictLimit = window->lowLimit;
+ }
+ /* On reaching window size, dictionaries are invalidated */
+ if (loadedDictEndPtr) *loadedDictEndPtr = 0;
+ if (dictMatchStatePtr) *dictMatchStatePtr = NULL;
+ }
+}
+
+/* Similar to ZSTD_window_enforceMaxDist(),
+ * but only invalidates dictionary
+ * when input progresses beyond window size.
+ * assumption : loadedDictEndPtr and dictMatchStatePtr are valid (non NULL)
+ * loadedDictEnd uses same referential as window->base
+ * maxDist is the window size */
+MEM_STATIC void
+ZSTD_checkDictValidity(const ZSTD_window_t* window,
+ const void* blockEnd,
+ U32 maxDist,
+ U32* loadedDictEndPtr,
+ const ZSTD_matchState_t** dictMatchStatePtr)
+{
+ assert(loadedDictEndPtr != NULL);
+ assert(dictMatchStatePtr != NULL);
+ { U32 const blockEndIdx = (U32)((BYTE const*)blockEnd - window->base);
+ U32 const loadedDictEnd = *loadedDictEndPtr;
+ DEBUGLOG(5, "ZSTD_checkDictValidity: blockEndIdx=%u, maxDist=%u, loadedDictEnd=%u",
+ (unsigned)blockEndIdx, (unsigned)maxDist, (unsigned)loadedDictEnd);
+ assert(blockEndIdx >= loadedDictEnd);
+
+ if (blockEndIdx > loadedDictEnd + maxDist) {
+ /* On reaching window size, dictionaries are invalidated.
+ * For simplification, if window size is reached anywhere within next block,
+ * the dictionary is invalidated for the full block.
+ */
+ DEBUGLOG(6, "invalidating dictionary for current block (distance > windowSize)");
+ *loadedDictEndPtr = 0;
+ *dictMatchStatePtr = NULL;
+ } else {
+ if (*loadedDictEndPtr != 0) {
+ DEBUGLOG(6, "dictionary considered valid for current block");
+ } } }
+}
+
+MEM_STATIC void ZSTD_window_init(ZSTD_window_t* window) {
+ ZSTD_memset(window, 0, sizeof(*window));
+ window->base = (BYTE const*)"";
+ window->dictBase = (BYTE const*)"";
+ window->dictLimit = 1; /* start from 1, so that 1st position is valid */
+ window->lowLimit = 1; /* it ensures first and later CCtx usages compress the same */
+ window->nextSrc = window->base + 1; /* see issue #1241 */
+}
+
+/*
+ * ZSTD_window_update():
+ * Updates the window by appending [src, src + srcSize) to the window.
+ * If it is not contiguous, the current prefix becomes the extDict, and we
+ * forget about the extDict. Handles overlap of the prefix and extDict.
+ * Returns non-zero if the segment is contiguous.
+ */
+MEM_STATIC U32 ZSTD_window_update(ZSTD_window_t* window,
+ void const* src, size_t srcSize)
+{
+ BYTE const* const ip = (BYTE const*)src;
+ U32 contiguous = 1;
+ DEBUGLOG(5, "ZSTD_window_update");
+ if (srcSize == 0)
+ return contiguous;
+ assert(window->base != NULL);
+ assert(window->dictBase != NULL);
+ /* Check if blocks follow each other */
+ if (src != window->nextSrc) {
+ /* not contiguous */
+ size_t const distanceFromBase = (size_t)(window->nextSrc - window->base);
+ DEBUGLOG(5, "Non contiguous blocks, new segment starts at %u", window->dictLimit);
+ window->lowLimit = window->dictLimit;
+ assert(distanceFromBase == (size_t)(U32)distanceFromBase); /* should never overflow */
+ window->dictLimit = (U32)distanceFromBase;
+ window->dictBase = window->base;
+ window->base = ip - distanceFromBase;
+ /* ms->nextToUpdate = window->dictLimit; */
+ if (window->dictLimit - window->lowLimit < HASH_READ_SIZE) window->lowLimit = window->dictLimit; /* too small extDict */
+ contiguous = 0;
+ }
+ window->nextSrc = ip + srcSize;
+ /* if input and dictionary overlap : reduce dictionary (area presumed modified by input) */
+ if ( (ip+srcSize > window->dictBase + window->lowLimit)
+ & (ip < window->dictBase + window->dictLimit)) {
+ ptrdiff_t const highInputIdx = (ip + srcSize) - window->dictBase;
+ U32 const lowLimitMax = (highInputIdx > (ptrdiff_t)window->dictLimit) ? window->dictLimit : (U32)highInputIdx;
+ window->lowLimit = lowLimitMax;
+ DEBUGLOG(5, "Overlapping extDict and input : new lowLimit = %u", window->lowLimit);
+ }
+ return contiguous;
+}
+
+/*
+ * Returns the lowest allowed match index. It may either be in the ext-dict or the prefix.
+ */
+MEM_STATIC U32 ZSTD_getLowestMatchIndex(const ZSTD_matchState_t* ms, U32 curr, unsigned windowLog)
+{
+ U32 const maxDistance = 1U << windowLog;
+ U32 const lowestValid = ms->window.lowLimit;
+ U32 const withinWindow = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid;
+ U32 const isDictionary = (ms->loadedDictEnd != 0);
+ /* When using a dictionary the entire dictionary is valid if a single byte of the dictionary
+ * is within the window. We invalidate the dictionary (and set loadedDictEnd to 0) when it isn't
+ * valid for the entire block. So this check is sufficient to find the lowest valid match index.
+ */
+ U32 const matchLowest = isDictionary ? lowestValid : withinWindow;
+ return matchLowest;
+}
+
+/*
+ * Returns the lowest allowed match index in the prefix.
+ */
+MEM_STATIC U32 ZSTD_getLowestPrefixIndex(const ZSTD_matchState_t* ms, U32 curr, unsigned windowLog)
+{
+ U32 const maxDistance = 1U << windowLog;
+ U32 const lowestValid = ms->window.dictLimit;
+ U32 const withinWindow = (curr - lowestValid > maxDistance) ? curr - maxDistance : lowestValid;
+ U32 const isDictionary = (ms->loadedDictEnd != 0);
+ /* When computing the lowest prefix index we need to take the dictionary into account to handle
+ * the edge case where the dictionary and the source are contiguous in memory.
+ */
+ U32 const matchLowest = isDictionary ? lowestValid : withinWindow;
+ return matchLowest;
+}
+
+
+
+/* debug functions */
+#if (DEBUGLEVEL>=2)
+
+MEM_STATIC double ZSTD_fWeight(U32 rawStat)
+{
+ U32 const fp_accuracy = 8;
+ U32 const fp_multiplier = (1 << fp_accuracy);
+ U32 const newStat = rawStat + 1;
+ U32 const hb = ZSTD_highbit32(newStat);
+ U32 const BWeight = hb * fp_multiplier;
+ U32 const FWeight = (newStat << fp_accuracy) >> hb;
+ U32 const weight = BWeight + FWeight;
+ assert(hb + fp_accuracy < 31);
+ return (double)weight / fp_multiplier;
+}
+
+/* display a table content,
+ * listing each element, its frequency, and its predicted bit cost */
+MEM_STATIC void ZSTD_debugTable(const U32* table, U32 max)
+{
+ unsigned u, sum;
+ for (u=0, sum=0; u<=max; u++) sum += table[u];
+ DEBUGLOG(2, "total nb elts: %u", sum);
+ for (u=0; u<=max; u++) {
+ DEBUGLOG(2, "%2u: %5u (%.2f)",
+ u, table[u], ZSTD_fWeight(sum) - ZSTD_fWeight(table[u]) );
+ }
+}
+
+#endif
+
+
+
+/* ===============================================================
+ * Shared internal declarations
+ * These prototypes may be called from sources not in lib/compress
+ * =============================================================== */
+
+/* ZSTD_loadCEntropy() :
+ * dict : must point at beginning of a valid zstd dictionary.
+ * return : size of dictionary header (size of magic number + dict ID + entropy tables)
+ * assumptions : magic number supposed already checked
+ * and dictSize >= 8 */
+size_t ZSTD_loadCEntropy(ZSTD_compressedBlockState_t* bs, void* workspace,
+ const void* const dict, size_t dictSize);
+
+void ZSTD_reset_compressedBlockState(ZSTD_compressedBlockState_t* bs);
+
+/* ==============================================================
+ * Private declarations
+ * These prototypes shall only be called from within lib/compress
+ * ============================================================== */
+
+/* ZSTD_getCParamsFromCCtxParams() :
+ * cParams are built depending on compressionLevel, src size hints,
+ * LDM and manually set compression parameters.
+ * Note: srcSizeHint == 0 means 0!
+ */
+ZSTD_compressionParameters ZSTD_getCParamsFromCCtxParams(
+ const ZSTD_CCtx_params* CCtxParams, U64 srcSizeHint, size_t dictSize, ZSTD_cParamMode_e mode);
+
+/*! ZSTD_initCStream_internal() :
+ * Private use only. Init streaming operation.
+ * expects params to be valid.
+ * must receive dict, or cdict, or none, but not both.
+ * @return : 0, or an error code */
+size_t ZSTD_initCStream_internal(ZSTD_CStream* zcs,
+ const void* dict, size_t dictSize,
+ const ZSTD_CDict* cdict,
+ const ZSTD_CCtx_params* params, unsigned long long pledgedSrcSize);
+
+void ZSTD_resetSeqStore(seqStore_t* ssPtr);
+
+/*! ZSTD_getCParamsFromCDict() :
+ * as the name implies */
+ZSTD_compressionParameters ZSTD_getCParamsFromCDict(const ZSTD_CDict* cdict);
+
+/* ZSTD_compressBegin_advanced_internal() :
+ * Private use only. To be called from zstdmt_compress.c. */
+size_t ZSTD_compressBegin_advanced_internal(ZSTD_CCtx* cctx,
+ const void* dict, size_t dictSize,
+ ZSTD_dictContentType_e dictContentType,
+ ZSTD_dictTableLoadMethod_e dtlm,
+ const ZSTD_CDict* cdict,
+ const ZSTD_CCtx_params* params,
+ unsigned long long pledgedSrcSize);
+
+/* ZSTD_compress_advanced_internal() :
+ * Private use only. To be called from zstdmt_compress.c. */
+size_t ZSTD_compress_advanced_internal(ZSTD_CCtx* cctx,
+ void* dst, size_t dstCapacity,
+ const void* src, size_t srcSize,
+ const void* dict,size_t dictSize,
+ const ZSTD_CCtx_params* params);
+
+
+/* ZSTD_writeLastEmptyBlock() :
+ * output an empty Block with end-of-frame mark to complete a frame
+ * @return : size of data written into `dst` (== ZSTD_blockHeaderSize (defined in zstd_internal.h))
+ * or an error code if `dstCapacity` is too small (<ZSTD_blockHeaderSize)
+ */
+size_t ZSTD_writeLastEmptyBlock(void* dst, size_t dstCapacity);
+
+
+/* ZSTD_referenceExternalSequences() :
+ * Must be called before starting a compression operation.
+ * seqs must parse a prefix of the source.
+ * This cannot be used when long range matching is enabled.
+ * Zstd will use these sequences, and pass the literals to a secondary block
+ * compressor.
+ * @return : An error code on failure.
+ * NOTE: seqs are not verified! Invalid sequences can cause out-of-bounds memory
+ * access and data corruption.
+ */
+size_t ZSTD_referenceExternalSequences(ZSTD_CCtx* cctx, rawSeq* seq, size_t nbSeq);
+
+/* ZSTD_cycleLog() :
+ * condition for correct operation : hashLog > 1 */
+U32 ZSTD_cycleLog(U32 hashLog, ZSTD_strategy strat);
+
+/* ZSTD_CCtx_trace() :
+ * Trace the end of a compression call.
+ */
+void ZSTD_CCtx_trace(ZSTD_CCtx* cctx, size_t extraCSize);
+
+#endif /* ZSTD_COMPRESS_H */