Merge branch 'zstd-minimal' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull zstd support from Chris Mason:
 "Nick Terrell's patch series to add zstd support to the kernel has been
  floating around for a while. After talking with Dave Sterba, Herbert
  and Phillip, we decided to send the whole thing in as one pull
  request.

  zstd is a big win in speed over zlib and in compression ratio over
  lzo, and the compression team here at FB has gotten great results
  using it in production. Nick will continue to update the kernel side
  with new improvements from the open source zstd userland code.

  Nick has a number of benchmarks for the main zstd code in his lib/zstd
  commit:

      I ran the benchmarks on a Ubuntu 14.04 VM with 2 cores and 4 GiB
      of RAM. The VM is running on a MacBook Pro with a 3.1 GHz Intel
      Core i7 processor, 16 GB of RAM, and a SSD. I benchmarked using
      `silesia.tar` [3], which is 211,988,480 B large. Run the following
      commands for the benchmark:

        sudo modprobe zstd_compress_test
        sudo mknod zstd_compress_test c 245 0
        sudo cp silesia.tar zstd_compress_test

      The time is reported by the time of the userland `cp`.
      The MB/s is computed with

        1,536,217,008 B / time(buffer size, hash)

      which includes the time to copy from userland.
      The Adjusted MB/s is computed with

        1,536,217,088 B / (time(buffer size, hash) - time(buffer size, none)).

      The memory reported is the amount of memory the compressor
      requests.

        | Method   | Size (B) | Time (s) | Ratio | MB/s    | Adj MB/s | Mem (MB) |
        |----------|----------|----------|-------|---------|----------|----------|
        | none     | 11988480 |    0.100 |     1 | 2119.88 |        - |        - |
        | zstd -1  | 73645762 |    1.044 | 2.878 |  203.05 |   224.56 |     1.23 |
        | zstd -3  | 66988878 |    1.761 | 3.165 |  120.38 |   127.63 |     2.47 |
        | zstd -5  | 65001259 |    2.563 | 3.261 |   82.71 |    86.07 |     2.86 |
        | zstd -10 | 60165346 |   13.242 | 3.523 |   16.01 |    16.13 |    13.22 |
        | zstd -15 | 58009756 |   47.601 | 3.654 |    4.45 |     4.46 |    21.61 |
        | zstd -19 | 54014593 |  102.835 | 3.925 |    2.06 |     2.06 |    60.15 |
        | zlib -1  | 77260026 |    2.895 | 2.744 |   73.23 |    75.85 |     0.27 |
        | zlib -3  | 72972206 |    4.116 | 2.905 |   51.50 |    52.79 |     0.27 |
        | zlib -6  | 68190360 |    9.633 | 3.109 |   22.01 |    22.24 |     0.27 |
        | zlib -9  | 67613382 |   22.554 | 3.135 |    9.40 |     9.44 |     0.27 |

      I benchmarked zstd decompression using the same method on the same
      machine. The benchmark file is located in the upstream zstd repo
      under `contrib/linux-kernel/zstd_decompress_test.c` [4]. The
      memory reported is the amount of memory required to decompress
      data compressed with the given compression level. If you know the
      maximum size of your input, you can reduce the memory usage of
      decompression irrespective of the compression level.

        | Method   | Time (s) | MB/s    | Adjusted MB/s | Memory (MB) |
        |----------|----------|---------|---------------|-------------|
        | none     |    0.025 | 8479.54 |             - |           - |
        | zstd -1  |    0.358 |  592.15 |        636.60 |        0.84 |
        | zstd -3  |    0.396 |  535.32 |        571.40 |        1.46 |
        | zstd -5  |    0.396 |  535.32 |        571.40 |        1.46 |
        | zstd -10 |    0.374 |  566.81 |        607.42 |        2.51 |
        | zstd -15 |    0.379 |  559.34 |        598.84 |        4.61 |
        | zstd -19 |    0.412 |  514.54 |        547.77 |        8.80 |
        | zlib -1  |    0.940 |  225.52 |        231.68 |        0.04 |
        | zlib -3  |    0.883 |  240.08 |        247.07 |        0.04 |
        | zlib -6  |    0.844 |  251.17 |        258.84 |        0.04 |
        | zlib -9  |    0.837 |  253.27 |        287.64 |        0.04 |

  I ran a long series of tests and benchmarks on the btrfs side and the
  gains are very similar to the core benchmarks Nick ran"

* 'zstd-minimal' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  squashfs: Add zstd support
  btrfs: Add zstd support
  lib: Add zstd modules
  lib: Add xxhash module

1 files changed, 2528 insertions, 0 deletions

diff --git a/lib/zstd/decompress.c b/lib/zstd/decompress.c
new file mode 100644
index 000000000000..b17846725ca0
--- /dev/null
+++ b/lib/zstd/decompress.c
@@ -0,0 +1,2528 @@
+/**
+ * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of https://github.com/facebook/zstd.
+ * An additional grant of patent rights can be found in the PATENTS file in the
+ * same directory.
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ */
+
+/* ***************************************************************
+*  Tuning parameters
+*****************************************************************/
+/*!
+*  MAXWINDOWSIZE_DEFAULT :
+*  maximum window size accepted by DStream, by default.
+*  Frames requiring more memory will be rejected.
+*/
+#ifndef ZSTD_MAXWINDOWSIZE_DEFAULT
+#define ZSTD_MAXWINDOWSIZE_DEFAULT ((1 << ZSTD_WINDOWLOG_MAX) + 1) /* defined within zstd.h */
+#endif
+
+/*-*******************************************************
+*  Dependencies
+*********************************************************/
+#include "fse.h"
+#include "huf.h"
+#include "mem.h" /* low level memory routines */
+#include "zstd_internal.h"
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h> /* memcpy, memmove, memset */
+
+#define ZSTD_PREFETCH(ptr) __builtin_prefetch(ptr, 0, 0)
+
+/*-*************************************
+*  Macros
+***************************************/
+#define ZSTD_isError ERR_isError /* for inlining */
+#define FSE_isError ERR_isError
+#define HUF_isError ERR_isError
+
+/*_*******************************************************
+*  Memory operations
+**********************************************************/
+static void ZSTD_copy4(void *dst, const void *src) { memcpy(dst, src, 4); }
+
+/*-*************************************************************
+*   Context management
+***************************************************************/
+typedef enum {
+	ZSTDds_getFrameHeaderSize,
+	ZSTDds_decodeFrameHeader,
+	ZSTDds_decodeBlockHeader,
+	ZSTDds_decompressBlock,
+	ZSTDds_decompressLastBlock,
+	ZSTDds_checkChecksum,
+	ZSTDds_decodeSkippableHeader,
+	ZSTDds_skipFrame
+} ZSTD_dStage;
+
+typedef struct {
+	FSE_DTable LLTable[FSE_DTABLE_SIZE_U32(LLFSELog)];
+	FSE_DTable OFTable[FSE_DTABLE_SIZE_U32(OffFSELog)];
+	FSE_DTable MLTable[FSE_DTABLE_SIZE_U32(MLFSELog)];
+	HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)]; /* can accommodate HUF_decompress4X */
+	U64 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32 / 2];
+	U32 rep[ZSTD_REP_NUM];
+} ZSTD_entropyTables_t;
+
+struct ZSTD_DCtx_s {
+	const FSE_DTable *LLTptr;
+	const FSE_DTable *MLTptr;
+	const FSE_DTable *OFTptr;
+	const HUF_DTable *HUFptr;
+	ZSTD_entropyTables_t entropy;
+	const void *previousDstEnd; /* detect continuity */
+	const void *base;	   /* start of curr segment */
+	const void *vBase;	  /* virtual start of previous segment if it was just before curr one */
+	const void *dictEnd;	/* end of previous segment */
+	size_t expected;
+	ZSTD_frameParams fParams;
+	blockType_e bType; /* used in ZSTD_decompressContinue(), to transfer blockType between header decoding and block decoding stages */
+	ZSTD_dStage stage;
+	U32 litEntropy;
+	U32 fseEntropy;
+	struct xxh64_state xxhState;
+	size_t headerSize;
+	U32 dictID;
+	const BYTE *litPtr;
+	ZSTD_customMem customMem;
+	size_t litSize;
+	size_t rleSize;
+	BYTE litBuffer[ZSTD_BLOCKSIZE_ABSOLUTEMAX + WILDCOPY_OVERLENGTH];
+	BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
+}; /* typedef'd to ZSTD_DCtx within "zstd.h" */
+
+size_t ZSTD_DCtxWorkspaceBound(void) { return ZSTD_ALIGN(sizeof(ZSTD_stack)) + ZSTD_ALIGN(sizeof(ZSTD_DCtx)); }
+
+size_t ZSTD_decompressBegin(ZSTD_DCtx *dctx)
+{
+	dctx->expected = ZSTD_frameHeaderSize_prefix;
+	dctx->stage = ZSTDds_getFrameHeaderSize;
+	dctx->previousDstEnd = NULL;
+	dctx->base = NULL;
+	dctx->vBase = NULL;
+	dctx->dictEnd = NULL;
+	dctx->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001); /* cover both little and big endian */
+	dctx->litEntropy = dctx->fseEntropy = 0;
+	dctx->dictID = 0;
+	ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.rep) == sizeof(repStartValue));
+	memcpy(dctx->entropy.rep, repStartValue, sizeof(repStartValue)); /* initial repcodes */
+	dctx->LLTptr = dctx->entropy.LLTable;
+	dctx->MLTptr = dctx->entropy.MLTable;
+	dctx->OFTptr = dctx->entropy.OFTable;
+	dctx->HUFptr = dctx->entropy.hufTable;
+	return 0;
+}
+
+ZSTD_DCtx *ZSTD_createDCtx_advanced(ZSTD_customMem customMem)
+{
+	ZSTD_DCtx *dctx;
+
+	if (!customMem.customAlloc || !customMem.customFree)
+		return NULL;
+
+	dctx = (ZSTD_DCtx *)ZSTD_malloc(sizeof(ZSTD_DCtx), customMem);
+	if (!dctx)
+		return NULL;
+	memcpy(&dctx->customMem, &customMem, sizeof(customMem));
+	ZSTD_decompressBegin(dctx);
+	return dctx;
+}
+
+ZSTD_DCtx *ZSTD_initDCtx(void *workspace, size_t workspaceSize)
+{
+	ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
+	return ZSTD_createDCtx_advanced(stackMem);
+}
+
+size_t ZSTD_freeDCtx(ZSTD_DCtx *dctx)
+{
+	if (dctx == NULL)
+		return 0; /* support free on NULL */
+	ZSTD_free(dctx, dctx->customMem);
+	return 0; /* reserved as a potential error code in the future */
+}
+
+void ZSTD_copyDCtx(ZSTD_DCtx *dstDCtx, const ZSTD_DCtx *srcDCtx)
+{
+	size_t const workSpaceSize = (ZSTD_BLOCKSIZE_ABSOLUTEMAX + WILDCOPY_OVERLENGTH) + ZSTD_frameHeaderSize_max;
+	memcpy(dstDCtx, srcDCtx, sizeof(ZSTD_DCtx) - workSpaceSize); /* no need to copy workspace */
+}
+
+static void ZSTD_refDDict(ZSTD_DCtx *dstDCtx, const ZSTD_DDict *ddict);
+
+/*-*************************************************************
+*   Decompression section
+***************************************************************/
+
+/*! ZSTD_isFrame() :
+ *  Tells if the content of `buffer` starts with a valid Frame Identifier.
+ *  Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0.
+ *  Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled.
+ *  Note 3 : Skippable Frame Identifiers are considered valid. */
+unsigned ZSTD_isFrame(const void *buffer, size_t size)
+{
+	if (size < 4)
+		return 0;
+	{
+		U32 const magic = ZSTD_readLE32(buffer);
+		if (magic == ZSTD_MAGICNUMBER)
+			return 1;
+		if ((magic & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START)
+			return 1;
+	}
+	return 0;
+}
+
+/** ZSTD_frameHeaderSize() :
+*   srcSize must be >= ZSTD_frameHeaderSize_prefix.
+*   @return : size of the Frame Header */
+static size_t ZSTD_frameHeaderSize(const void *src, size_t srcSize)
+{
+	if (srcSize < ZSTD_frameHeaderSize_prefix)
+		return ERROR(srcSize_wrong);
+	{
+		BYTE const fhd = ((const BYTE *)src)[4];
+		U32 const dictID = fhd & 3;
+		U32 const singleSegment = (fhd >> 5) & 1;
+		U32 const fcsId = fhd >> 6;
+		return ZSTD_frameHeaderSize_prefix + !singleSegment + ZSTD_did_fieldSize[dictID] + ZSTD_fcs_fieldSize[fcsId] + (singleSegment && !fcsId);
+	}
+}
+
+/** ZSTD_getFrameParams() :
+*   decode Frame Header, or require larger `srcSize`.
+*   @return : 0, `fparamsPtr` is correctly filled,
+*            >0, `srcSize` is too small, result is expected `srcSize`,
+*             or an error code, which can be tested using ZSTD_isError() */
+size_t ZSTD_getFrameParams(ZSTD_frameParams *fparamsPtr, const void *src, size_t srcSize)
+{
+	const BYTE *ip = (const BYTE *)src;
+
+	if (srcSize < ZSTD_frameHeaderSize_prefix)
+		return ZSTD_frameHeaderSize_prefix;
+	if (ZSTD_readLE32(src) != ZSTD_MAGICNUMBER) {
+		if ((ZSTD_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
+			if (srcSize < ZSTD_skippableHeaderSize)
+				return ZSTD_skippableHeaderSize; /* magic number + skippable frame length */
+			memset(fparamsPtr, 0, sizeof(*fparamsPtr));
+			fparamsPtr->frameContentSize = ZSTD_readLE32((const char *)src + 4);
+			fparamsPtr->windowSize = 0; /* windowSize==0 means a frame is skippable */
+			return 0;
+		}
+		return ERROR(prefix_unknown);
+	}
+
+	/* ensure there is enough `srcSize` to fully read/decode frame header */
+	{
+		size_t const fhsize = ZSTD_frameHeaderSize(src, srcSize);
+		if (srcSize < fhsize)
+			return fhsize;
+	}
+
+	{
+		BYTE const fhdByte = ip[4];
+		size_t pos = 5;
+		U32 const dictIDSizeCode = fhdByte & 3;
+		U32 const checksumFlag = (fhdByte >> 2) & 1;
+		U32 const singleSegment = (fhdByte >> 5) & 1;
+		U32 const fcsID = fhdByte >> 6;
+		U32 const windowSizeMax = 1U << ZSTD_WINDOWLOG_MAX;
+		U32 windowSize = 0;
+		U32 dictID = 0;
+		U64 frameContentSize = 0;
+		if ((fhdByte & 0x08) != 0)
+			return ERROR(frameParameter_unsupported); /* reserved bits, which must be zero */
+		if (!singleSegment) {
+			BYTE const wlByte = ip[pos++];
+			U32 const windowLog = (wlByte >> 3) + ZSTD_WINDOWLOG_ABSOLUTEMIN;
+			if (windowLog > ZSTD_WINDOWLOG_MAX)
+				return ERROR(frameParameter_windowTooLarge); /* avoids issue with 1 << windowLog */
+			windowSize = (1U << windowLog);
+			windowSize += (windowSize >> 3) * (wlByte & 7);
+		}
+
+		switch (dictIDSizeCode) {
+		default: /* impossible */
+		case 0: break;
+		case 1:
+			dictID = ip[pos];
+			pos++;
+			break;
+		case 2:
+			dictID = ZSTD_readLE16(ip + pos);
+			pos += 2;
+			break;
+		case 3:
+			dictID = ZSTD_readLE32(ip + pos);
+			pos += 4;
+			break;
+		}
+		switch (fcsID) {
+		default: /* impossible */
+		case 0:
+			if (singleSegment)
+				frameContentSize = ip[pos];
+			break;
+		case 1: frameContentSize = ZSTD_readLE16(ip + pos) + 256; break;
+		case 2: frameContentSize = ZSTD_readLE32(ip + pos); break;
+		case 3: frameContentSize = ZSTD_readLE64(ip + pos); break;
+		}
+		if (!windowSize)
+			windowSize = (U32)frameContentSize;
+		if (windowSize > windowSizeMax)
+			return ERROR(frameParameter_windowTooLarge);
+		fparamsPtr->frameContentSize = frameContentSize;
+		fparamsPtr->windowSize = windowSize;
+		fparamsPtr->dictID = dictID;
+		fparamsPtr->checksumFlag = checksumFlag;
+	}
+	return 0;
+}
+
+/** ZSTD_getFrameContentSize() :
+*   compatible with legacy mode
+*   @return : decompressed size of the single frame pointed to be `src` if known, otherwise
+*             - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
+*             - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) */
+unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize)
+{
+	{
+		ZSTD_frameParams fParams;
+		if (ZSTD_getFrameParams(&fParams, src, srcSize) != 0)
+			return ZSTD_CONTENTSIZE_ERROR;
+		if (fParams.windowSize == 0) {
+			/* Either skippable or empty frame, size == 0 either way */
+			return 0;
+		} else if (fParams.frameContentSize != 0) {
+			return fParams.frameContentSize;
+		} else {
+			return ZSTD_CONTENTSIZE_UNKNOWN;
+		}
+	}
+}
+
+/** ZSTD_findDecompressedSize() :
+ *  compatible with legacy mode
+ *  `srcSize` must be the exact length of some number of ZSTD compressed and/or
+ *      skippable frames
+ *  @return : decompressed size of the frames contained */
+unsigned long long ZSTD_findDecompressedSize(const void *src, size_t srcSize)
+{
+	{
+		unsigned long long totalDstSize = 0;
+		while (srcSize >= ZSTD_frameHeaderSize_prefix) {
+			const U32 magicNumber = ZSTD_readLE32(src);
+
+			if ((magicNumber & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
+				size_t skippableSize;
+				if (srcSize < ZSTD_skippableHeaderSize)
+					return ERROR(srcSize_wrong);
+				skippableSize = ZSTD_readLE32((const BYTE *)src + 4) + ZSTD_skippableHeaderSize;
+				if (srcSize < skippableSize) {
+					return ZSTD_CONTENTSIZE_ERROR;
+				}
+
+				src = (const BYTE *)src + skippableSize;
+				srcSize -= skippableSize;
+				continue;
+			}
+
+			{
+				unsigned long long const ret = ZSTD_getFrameContentSize(src, srcSize);
+				if (ret >= ZSTD_CONTENTSIZE_ERROR)
+					return ret;
+
+				/* check for overflow */
+				if (totalDstSize + ret < totalDstSize)
+					return ZSTD_CONTENTSIZE_ERROR;
+				totalDstSize += ret;
+			}
+			{
+				size_t const frameSrcSize = ZSTD_findFrameCompressedSize(src, srcSize);
+				if (ZSTD_isError(frameSrcSize)) {
+					return ZSTD_CONTENTSIZE_ERROR;
+				}
+
+				src = (const BYTE *)src + frameSrcSize;
+				srcSize -= frameSrcSize;
+			}
+		}
+
+		if (srcSize) {
+			return ZSTD_CONTENTSIZE_ERROR;
+		}
+
+		return totalDstSize;
+	}
+}
+
+/** ZSTD_decodeFrameHeader() :
+*   `headerSize` must be the size provided by ZSTD_frameHeaderSize().
+*   @return : 0 if success, or an error code, which can be tested using ZSTD_isError() */
+static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx *dctx, const void *src, size_t headerSize)
+{
+	size_t const result = ZSTD_getFrameParams(&(dctx->fParams), src, headerSize);
+	if (ZSTD_isError(result))
+		return result; /* invalid header */
+	if (result > 0)
+		return ERROR(srcSize_wrong); /* headerSize too small */
+	if (dctx->fParams.dictID && (dctx->dictID != dctx->fParams.dictID))
+		return ERROR(dictionary_wrong);
+	if (dctx->fParams.checksumFlag)
+		xxh64_reset(&dctx->xxhState, 0);
+	return 0;
+}
+
+typedef struct {
+	blockType_e blockType;
+	U32 lastBlock;
+	U32 origSize;
+} blockProperties_t;
+
+/*! ZSTD_getcBlockSize() :
+*   Provides the size of compressed block from block header `src` */
+size_t ZSTD_getcBlockSize(const void *src, size_t srcSize, blockProperties_t *bpPtr)
+{
+	if (srcSize < ZSTD_blockHeaderSize)
+		return ERROR(srcSize_wrong);
+	{
+		U32 const cBlockHeader = ZSTD_readLE24(src);
+		U32 const cSize = cBlockHeader >> 3;
+		bpPtr->lastBlock = cBlockHeader & 1;
+		bpPtr->blockType = (blockType_e)((cBlockHeader >> 1) & 3);
+		bpPtr->origSize = cSize; /* only useful for RLE */
+		if (bpPtr->blockType == bt_rle)
+			return 1;
+		if (bpPtr->blockType == bt_reserved)
+			return ERROR(corruption_detected);
+		return cSize;
+	}
+}
+
+static size_t ZSTD_copyRawBlock(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
+{
+	if (srcSize > dstCapacity)
+		return ERROR(dstSize_tooSmall);
+	memcpy(dst, src, srcSize);
+	return srcSize;
+}
+
+static size_t ZSTD_setRleBlock(void *dst, size_t dstCapacity, const void *src, size_t srcSize, size_t regenSize)
+{
+	if (srcSize != 1)
+		return ERROR(srcSize_wrong);
+	if (regenSize > dstCapacity)
+		return ERROR(dstSize_tooSmall);
+	memset(dst, *(const BYTE *)src, regenSize);
+	return regenSize;
+}
+
+/*! ZSTD_decodeLiteralsBlock() :
+	@return : nb of bytes read from src (< srcSize ) */
+size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx *dctx, const void *src, size_t srcSize) /* note : srcSize < BLOCKSIZE */
+{
+	if (srcSize < MIN_CBLOCK_SIZE)
+		return ERROR(corruption_detected);
+
+	{
+		const BYTE *const istart = (const BYTE *)src;
+		symbolEncodingType_e const litEncType = (symbolEncodingType_e)(istart[0] & 3);
+
+		switch (litEncType) {
+		case set_repeat:
+			if (dctx->litEntropy == 0)
+				return ERROR(dictionary_corrupted);
+		/* fall-through */
+		case set_compressed:
+			if (srcSize < 5)
+				return ERROR(corruption_detected); /* srcSize >= MIN_CBLOCK_SIZE == 3; here we need up to 5 for case 3 */
+			{
+				size_t lhSize, litSize, litCSize;
+				U32 singleStream = 0;
+				U32 const lhlCode = (istart[0] >> 2) & 3;
+				U32 const lhc = ZSTD_readLE32(istart);
+				switch (lhlCode) {
+				case 0:
+				case 1:
+				default: /* note : default is impossible, since lhlCode into [0..3] */
+					/* 2 - 2 - 10 - 10 */
+					singleStream = !lhlCode;
+					lhSize = 3;
+					litSize = (lhc >> 4) & 0x3FF;
+					litCSize = (lhc >> 14) & 0x3FF;
+					break;
+				case 2:
+					/* 2 - 2 - 14 - 14 */
+					lhSize = 4;
+					litSize = (lhc >> 4) & 0x3FFF;
+					litCSize = lhc >> 18;
+					break;
+				case 3:
+					/* 2 - 2 - 18 - 18 */
+					lhSize = 5;
+					litSize = (lhc >> 4) & 0x3FFFF;
+					litCSize = (lhc >> 22) + (istart[4] << 10);
+					break;
+				}
+				if (litSize > ZSTD_BLOCKSIZE_ABSOLUTEMAX)
+					return ERROR(corruption_detected);
+				if (litCSize + lhSize > srcSize)
+					return ERROR(corruption_detected);
+
+				if (HUF_isError(
+					(litEncType == set_repeat)
+					    ? (singleStream ? HUF_decompress1X_usingDTable(dctx->litBuffer, litSize, istart + lhSize, litCSize, dctx->HUFptr)
+							    : HUF_decompress4X_usingDTable(dctx->litBuffer, litSize, istart + lhSize, litCSize, dctx->HUFptr))
+					    : (singleStream
+						   ? HUF_decompress1X2_DCtx_wksp(dctx->entropy.hufTable, dctx->litBuffer, litSize, istart + lhSize, litCSize,
+										 dctx->entropy.workspace, sizeof(dctx->entropy.workspace))
+						   : HUF_decompress4X_hufOnly_wksp(dctx->entropy.hufTable, dctx->litBuffer, litSize, istart + lhSize, litCSize,
+										   dctx->entropy.workspace, sizeof(dctx->entropy.workspace)))))
+					return ERROR(corruption_detected);
+
+				dctx->litPtr = dctx->litBuffer;
+				dctx->litSize = litSize;
+				dctx->litEntropy = 1;
+				if (litEncType == set_compressed)
+					dctx->HUFptr = dctx->entropy.hufTable;
+				memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
+				return litCSize + lhSize;
+			}
+
+		case set_basic: {
+			size_t litSize, lhSize;
+			U32 const lhlCode = ((istart[0]) >> 2) & 3;
+			switch (lhlCode) {
+			case 0:
+			case 2:
+			default: /* note : default is impossible, since lhlCode into [0..3] */
+				lhSize = 1;
+				litSize = istart[0] >> 3;
+				break;
+			case 1:
+				lhSize = 2;
+				litSize = ZSTD_readLE16(istart) >> 4;
+				break;
+			case 3:
+				lhSize = 3;
+				litSize = ZSTD_readLE24(istart) >> 4;
+				break;
+			}
+
+			if (lhSize + litSize + WILDCOPY_OVERLENGTH > srcSize) { /* risk reading beyond src buffer with wildcopy */
+				if (litSize + lhSize > srcSize)
+					return ERROR(corruption_detected);
+				memcpy(dctx->litBuffer, istart + lhSize, litSize);
+				dctx->litPtr = dctx->litBuffer;
+				dctx->litSize = litSize;
+				memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
+				return lhSize + litSize;
+			}
+			/* direct reference into compressed stream */
+			dctx->litPtr = istart + lhSize;
+			dctx->litSize = litSize;
+			return lhSize + litSize;
+		}
+
+		case set_rle: {
+			U32 const lhlCode = ((istart[0]) >> 2) & 3;
+			size_t litSize, lhSize;
+			switch (lhlCode) {
+			case 0:
+			case 2:
+			default: /* note : default is impossible, since lhlCode into [0..3] */
+				lhSize = 1;
+				litSize = istart[0] >> 3;
+				break;
+			case 1:
+				lhSize = 2;
+				litSize = ZSTD_readLE16(istart) >> 4;
+				break;
+			case 3:
+				lhSize = 3;
+				litSize = ZSTD_readLE24(istart) >> 4;
+				if (srcSize < 4)
+					return ERROR(corruption_detected); /* srcSize >= MIN_CBLOCK_SIZE == 3; here we need lhSize+1 = 4 */
+				break;
+			}
+			if (litSize > ZSTD_BLOCKSIZE_ABSOLUTEMAX)
+				return ERROR(corruption_detected);
+			memset(dctx->litBuffer, istart[lhSize], litSize + WILDCOPY_OVERLENGTH);
+			dctx->litPtr = dctx->litBuffer;
+			dctx->litSize = litSize;
+			return lhSize + 1;
+		}
+		default:
+			return ERROR(corruption_detected); /* impossible */
+		}
+	}
+}
+
+typedef union {
+	FSE_decode_t realData;
+	U32 alignedBy4;
+} FSE_decode_t4;
+
+static const FSE_decode_t4 LL_defaultDTable[(1 << LL_DEFAULTNORMLOG) + 1] = {
+    {{LL_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
+    {{0, 0, 4}},		 /* 0 : base, symbol, bits */
+    {{16, 0, 4}},
+    {{32, 1, 5}},
+    {{0, 3, 5}},
+    {{0, 4, 5}},
+    {{0, 6, 5}},
+    {{0, 7, 5}},
+    {{0, 9, 5}},
+    {{0, 10, 5}},
+    {{0, 12, 5}},
+    {{0, 14, 6}},
+    {{0, 16, 5}},
+    {{0, 18, 5}},
+    {{0, 19, 5}},
+    {{0, 21, 5}},
+    {{0, 22, 5}},
+    {{0, 24, 5}},
+    {{32, 25, 5}},
+    {{0, 26, 5}},
+    {{0, 27, 6}},
+    {{0, 29, 6}},
+    {{0, 31, 6}},
+    {{32, 0, 4}},
+    {{0, 1, 4}},
+    {{0, 2, 5}},
+    {{32, 4, 5}},
+    {{0, 5, 5}},
+    {{32, 7, 5}},
+    {{0, 8, 5}},
+    {{32, 10, 5}},
+    {{0, 11, 5}},
+    {{0, 13, 6}},
+    {{32, 16, 5}},
+    {{0, 17, 5}},
+    {{32, 19, 5}},
+    {{0, 20, 5}},
+    {{32, 22, 5}},
+    {{0, 23, 5}},
+    {{0, 25, 4}},
+    {{16, 25, 4}},
+    {{32, 26, 5}},
+    {{0, 28, 6}},
+    {{0, 30, 6}},
+    {{48, 0, 4}},
+    {{16, 1, 4}},
+    {{32, 2, 5}},
+    {{32, 3, 5}},
+    {{32, 5, 5}},
+    {{32, 6, 5}},
+    {{32, 8, 5}},
+    {{32, 9, 5}},
+    {{32, 11, 5}},
+    {{32, 12, 5}},
+    {{0, 15, 6}},
+    {{32, 17, 5}},
+    {{32, 18, 5}},
+    {{32, 20, 5}},
+    {{32, 21, 5}},
+    {{32, 23, 5}},
+    {{32, 24, 5}},
+    {{0, 35, 6}},
+    {{0, 34, 6}},
+    {{0, 33, 6}},
+    {{0, 32, 6}},
+}; /* LL_defaultDTable */
+
+static const FSE_decode_t4 ML_defaultDTable[(1 << ML_DEFAULTNORMLOG) + 1] = {
+    {{ML_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
+    {{0, 0, 6}},		 /* 0 : base, symbol, bits */
+    {{0, 1, 4}},
+    {{32, 2, 5}},
+    {{0, 3, 5}},
+    {{0, 5, 5}},
+    {{0, 6, 5}},
+    {{0, 8, 5}},
+    {{0, 10, 6}},
+    {{0, 13, 6}},
+    {{0, 16, 6}},
+    {{0, 19, 6}},
+    {{0, 22, 6}},
+    {{0, 25, 6}},
+    {{0, 28, 6}},
+    {{0, 31, 6}},
+    {{0, 33, 6}},
+    {{0, 35, 6}},
+    {{0, 37, 6}},
+    {{0, 39, 6}},
+    {{0, 41, 6}},
+    {{0, 43, 6}},
+    {{0, 45, 6}},
+    {{16, 1, 4}},
+    {{0, 2, 4}},
+    {{32, 3, 5}},
+    {{0, 4, 5}},
+    {{32, 6, 5}},
+    {{0, 7, 5}},
+    {{0, 9, 6}},
+    {{0, 12, 6}},
+    {{0, 15, 6}},
+    {{0, 18, 6}},
+    {{0, 21, 6}},
+    {{0, 24, 6}},
+    {{0, 27, 6}},
+    {{0, 30, 6}},
+    {{0, 32, 6}},
+    {{0, 34, 6}},
+    {{0, 36, 6}},
+    {{0, 38, 6}},
+    {{0, 40, 6}},
+    {{0, 42, 6}},
+    {{0, 44, 6}},
+    {{32, 1, 4}},
+    {{48, 1, 4}},
+    {{16, 2, 4}},
+    {{32, 4, 5}},
+    {{32, 5, 5}},
+    {{32, 7, 5}},
+    {{32, 8, 5}},
+    {{0, 11, 6}},
+    {{0, 14, 6}},
+    {{0, 17, 6}},
+    {{0, 20, 6}},
+    {{0, 23, 6}},
+    {{0, 26, 6}},
+    {{0, 29, 6}},
+    {{0, 52, 6}},
+    {{0, 51, 6}},
+    {{0, 50, 6}},
+    {{0, 49, 6}},
+    {{0, 48, 6}},
+    {{0, 47, 6}},
+    {{0, 46, 6}},
+}; /* ML_defaultDTable */
+
+static const FSE_decode_t4 OF_defaultDTable[(1 << OF_DEFAULTNORMLOG) + 1] = {
+    {{OF_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
+    {{0, 0, 5}},		 /* 0 : base, symbol, bits */
+    {{0, 6, 4}},
+    {{0, 9, 5}},
+    {{0, 15, 5}},
+    {{0, 21, 5}},
+    {{0, 3, 5}},
+    {{0, 7, 4}},
+    {{0, 12, 5}},
+    {{0, 18, 5}},
+    {{0, 23, 5}},
+    {{0, 5, 5}},
+    {{0, 8, 4}},
+    {{0, 14, 5}},
+    {{0, 20, 5}},
+    {{0, 2, 5}},
+    {{16, 7, 4}},
+    {{0, 11, 5}},
+    {{0, 17, 5}},
+    {{0, 22, 5}},
+    {{0, 4, 5}},
+    {{16, 8, 4}},
+    {{0, 13, 5}},
+    {{0, 19, 5}},
+    {{0, 1, 5}},
+    {{16, 6, 4}},
+    {{0, 10, 5}},
+    {{0, 16, 5}},
+    {{0, 28, 5}},
+    {{0, 27, 5}},
+    {{0, 26, 5}},
+    {{0, 25, 5}},
+    {{0, 24, 5}},
+}; /* OF_defaultDTable */
+
+/*! ZSTD_buildSeqTable() :
+	@return : nb bytes read from src,
+			  or an error code if it fails, testable with ZSTD_isError()
+*/
+static size_t ZSTD_buildSeqTable(FSE_DTable *DTableSpace, const FSE_DTable **DTablePtr, symbolEncodingType_e type, U32 max, U32 maxLog, const void *src,
+				 size_t srcSize, const FSE_decode_t4 *defaultTable, U32 flagRepeatTable, void *workspace, size_t workspaceSize)
+{
+	const void *const tmpPtr = defaultTable; /* bypass strict aliasing */
+	switch (type) {
+	case set_rle:
+		if (!srcSize)
+			return ERROR(srcSize_wrong);
+		if ((*(const BYTE *)src) > max)
+			return ERROR(corruption_detected);
+		FSE_buildDTable_rle(DTableSpace, *(const BYTE *)src);
+		*DTablePtr = DTableSpace;
+		return 1;
+	case set_basic: *DTablePtr = (const FSE_DTable *)tmpPtr; return 0;
+	case set_repeat:
+		if (!flagRepeatTable)
+			return ERROR(corruption_detected);
+		return 0;
+	default: /* impossible */
+	case set_compressed: {
+		U32 tableLog;
+		S16 *norm = (S16 *)workspace;
+		size_t const spaceUsed32 = ALIGN(sizeof(S16) * (MaxSeq + 1), sizeof(U32)) >> 2;
+
+		if ((spaceUsed32 << 2) > workspaceSize)
+			return ERROR(GENERIC);
+		workspace = (U32 *)workspace + spaceUsed32;
+		workspaceSize -= (spaceUsed32 << 2);
+		{
+			size_t const headerSize = FSE_readNCount(norm, &max, &tableLog, src, srcSize);
+			if (FSE_isError(headerSize))
+				return ERROR(corruption_detected);
+			if (tableLog > maxLog)
+				return ERROR(corruption_detected);
+			FSE_buildDTable_wksp(DTableSpace, norm, max, tableLog, workspace, workspaceSize);
+			*DTablePtr = DTableSpace;
+			return headerSize;
+		}
+	}
+	}
+}
+
+size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx *dctx, int *nbSeqPtr, const void *src, size_t srcSize)
+{
+	const BYTE *const istart = (const BYTE *const)src;
+	const BYTE *const iend = istart + srcSize;
+	const BYTE *ip = istart;
+
+	/* check */
+	if (srcSize < MIN_SEQUENCES_SIZE)
+		return ERROR(srcSize_wrong);
+
+	/* SeqHead */
+	{
+		int nbSeq = *ip++;
+		if (!nbSeq) {
+			*nbSeqPtr = 0;
+			return 1;
+		}
+		if (nbSeq > 0x7F) {
+			if (nbSeq == 0xFF) {
+				if (ip + 2 > iend)
+					return ERROR(srcSize_wrong);
+				nbSeq = ZSTD_readLE16(ip) + LONGNBSEQ, ip += 2;
+			} else {
+				if (ip >= iend)
+					return ERROR(srcSize_wrong);
+				nbSeq = ((nbSeq - 0x80) << 8) + *ip++;
+			}
+		}
+		*nbSeqPtr = nbSeq;
+	}
+
+	/* FSE table descriptors */
+	if (ip + 4 > iend)
+		return ERROR(srcSize_wrong); /* minimum possible size */
+	{
+		symbolEncodingType_e const LLtype = (symbolEncodingType_e)(*ip >> 6);
+		symbolEncodingType_e const OFtype = (symbolEncodingType_e)((*ip >> 4) & 3);
+		symbolEncodingType_e const MLtype = (symbolEncodingType_e)((*ip >> 2) & 3);
+		ip++;
+
+		/* Build DTables */
+		{
+			size_t const llhSize = ZSTD_buildSeqTable(dctx->entropy.LLTable, &dctx->LLTptr, LLtype, MaxLL, LLFSELog, ip, iend - ip,
+								  LL_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, sizeof(dctx->entropy.workspace));
+			if (ZSTD_isError(llhSize))
+				return ERROR(corruption_detected);
+			ip += llhSize;
+		}
+		{
+			size_t const ofhSize = ZSTD_buildSeqTable(dctx->entropy.OFTable, &dctx->OFTptr, OFtype, MaxOff, OffFSELog, ip, iend - ip,
+								  OF_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, sizeof(dctx->entropy.workspace));
+			if (ZSTD_isError(ofhSize))
+				return ERROR(corruption_detected);
+			ip += ofhSize;
+		}
+		{
+			size_t const mlhSize = ZSTD_buildSeqTable(dctx->entropy.MLTable, &dctx->MLTptr, MLtype, MaxML, MLFSELog, ip, iend - ip,
+								  ML_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, sizeof(dctx->entropy.workspace));
+			if (ZSTD_isError(mlhSize))
+				return ERROR(corruption_detected);
+			ip += mlhSize;
+		}
+	}
+
+	return ip - istart;
+}
+
+typedef struct {
+	size_t litLength;
+	size_t matchLength;
+	size_t offset;
+	const BYTE *match;
+} seq_t;
+
+typedef struct {
+	BIT_DStream_t DStream;
+	FSE_DState_t stateLL;
+	FSE_DState_t stateOffb;
+	FSE_DState_t stateML;
+	size_t prevOffset[ZSTD_REP_NUM];
+	const BYTE *base;
+	size_t pos;
+	uPtrDiff gotoDict;
+} seqState_t;
+
+FORCE_NOINLINE
+size_t ZSTD_execSequenceLast7(BYTE *op, BYTE *const oend, seq_t sequence, const BYTE **litPtr, const BYTE *const litLimit, const BYTE *const base,
+			      const BYTE *const vBase, const BYTE *const dictEnd)
+{
+	BYTE *const oLitEnd = op + sequence.litLength;
+	size_t const sequenceLength = sequence.litLength + sequence.matchLength;
+	BYTE *const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */
+	BYTE *const oend_w = oend - WILDCOPY_OVERLENGTH;
+	const BYTE *const iLitEnd = *litPtr + sequence.litLength;
+	const BYTE *match = oLitEnd - sequence.offset;
+
+	/* check */
+	if (oMatchEnd > oend)
+		return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
+	if (iLitEnd > litLimit)
+		return ERROR(corruption_detected); /* over-read beyond lit buffer */
+	if (oLitEnd <= oend_w)
+		return ERROR(GENERIC); /* Precondition */
+
+	/* copy literals */
+	if (op < oend_w) {
+		ZSTD_wildcopy(op, *litPtr, oend_w - op);
+		*litPtr += oend_w - op;
+		op = oend_w;
+	}
+	while (op < oLitEnd)
+		*op++ = *(*litPtr)++;
+
+	/* copy Match */
+	if (sequence.offset > (size_t)(oLitEnd - base)) {
+		/* offset beyond prefix */
+		if (sequence.offset > (size_t)(oLitEnd - vBase))
+			return ERROR(corruption_detected);
+		match = dictEnd - (base - match);
+		if (match + sequence.matchLength <= dictEnd) {
+			memmove(oLitEnd, match, sequence.matchLength);
+			return sequenceLength;
+		}
+		/* span extDict & currPrefixSegment */
+		{
+			size_t const length1 = dictEnd - match;
+			memmove(oLitEnd, match, length1);
+			op = oLitEnd + length1;
+			sequence.matchLength -= length1;
+			match = base;
+		}
+	}
+	while (op < oMatchEnd)
+		*op++ = *match++;
+	return sequenceLength;
+}
+
+static seq_t ZSTD_decodeSequence(seqState_t *seqState)
+{
+	seq_t seq;
+
+	U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
+	U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
+	U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= maxOff, by table construction */
+
+	U32 const llBits = LL_bits[llCode];
+	U32 const mlBits = ML_bits[mlCode];
+	U32 const ofBits = ofCode;
+	U32 const totalBits = llBits + mlBits + ofBits;
+
+	static const U32 LL_base[MaxLL + 1] = {0,  1,  2,  3,  4,  5,  6,  7,  8,    9,     10,    11,    12,    13,     14,     15,     16,     18,
+					       20, 22, 24, 28, 32, 40, 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000};
+
+	static const U32 ML_base[MaxML + 1] = {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,    33,     34,     35,     37,     39,     41,
+					       43, 47, 51, 59, 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803, 0x1003, 0x2003, 0x4003, 0x8003, 0x10003};
+
+	static const U32 OF_base[MaxOff + 1] = {0,       1,	1,	5,	0xD,      0x1D,      0x3D,      0x7D,      0xFD,     0x1FD,
+						0x3FD,   0x7FD,    0xFFD,    0x1FFD,   0x3FFD,   0x7FFD,    0xFFFD,    0x1FFFD,   0x3FFFD,  0x7FFFD,
+						0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD, 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD};
+
+	/* sequence */
+	{
+		size_t offset;
+		if (!ofCode)
+			offset = 0;
+		else {
+			offset = OF_base[ofCode] + BIT_readBitsFast(&seqState->DStream, ofBits); /* <=  (ZSTD_WINDOWLOG_MAX-1) bits */
+			if (ZSTD_32bits())
+				BIT_reloadDStream(&seqState->DStream);
+		}
+
+		if (ofCode <= 1) {
+			offset += (llCode == 0);
+			if (offset) {
+				size_t temp = (offset == 3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
+				temp += !temp; /* 0 is not valid; input is corrupted; force offset to 1 */
+				if (offset != 1)
+					seqState->prevOffset[2] = seqState->prevOffset[1];
+				seqState->prevOffset[1] = seqState->prevOffset[0];
+				seqState->prevOffset[0] = offset = temp;
+			} else {
+				offset = seqState->prevOffset[0];
+			}
+		} else {
+			seqState->prevOffset[2] = seqState->prevOffset[1];
+			seqState->prevOffset[1] = seqState->prevOffset[0];
+			seqState->prevOffset[0] = offset;
+		}
+		seq.offset = offset;
+	}
+
+	seq.matchLength = ML_base[mlCode] + ((mlCode > 31) ? BIT_readBitsFast(&seqState->DStream, mlBits) : 0); /* <=  16 bits */
+	if (ZSTD_32bits() && (mlBits + llBits > 24))
+		BIT_reloadDStream(&seqState->DStream);
+
+	seq.litLength = LL_base[llCode] + ((llCode > 15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <=  16 bits */
+	if (ZSTD_32bits() || (totalBits > 64 - 7 - (LLFSELog + MLFSELog + OffFSELog)))
+		BIT_reloadDStream(&seqState->DStream);
+
+	/* ANS state update */
+	FSE_updateState(&seqState->stateLL, &seqState->DStream); /* <=  9 bits */
+	FSE_updateState(&seqState->stateML, &seqState->DStream); /* <=  9 bits */
+	if (ZSTD_32bits())
+		BIT_reloadDStream(&seqState->DStream);		   /* <= 18 bits */
+	FSE_updateState(&seqState->stateOffb, &seqState->DStream); /* <=  8 bits */
+
+	seq.match = NULL;
+
+	return seq;
+}
+
+FORCE_INLINE
+size_t ZSTD_execSequence(BYTE *op, BYTE *const oend, seq_t sequence, const BYTE **litPtr, const BYTE *const litLimit, const BYTE *const base,
+			 const BYTE *const vBase, const BYTE *const dictEnd)
+{
+	BYTE *const oLitEnd = op + sequence.litLength;
+	size_t const sequenceLength = sequence.litLength + sequence.matchLength;
+	BYTE *const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */
+	BYTE *const oend_w = oend - WILDCOPY_OVERLENGTH;
+	const BYTE *const iLitEnd = *litPtr + sequence.litLength;
+	const BYTE *match = oLitEnd - sequence.offset;
+
+	/* check */
+	if (oMatchEnd > oend)
+		return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
+	if (iLitEnd > litLimit)
+		return ERROR(corruption_detected); /* over-read beyond lit buffer */
+	if (oLitEnd > oend_w)
+		return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, base, vBase, dictEnd);
+
+	/* copy Literals */
+	ZSTD_copy8(op, *litPtr);
+	if (sequence.litLength > 8)
+		ZSTD_wildcopy(op + 8, (*litPtr) + 8,
+			      sequence.litLength - 8); /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
+	op = oLitEnd;
+	*litPtr = iLitEnd; /* update for next sequence */
+
+	/* copy Match */
+	if (sequence.offset > (size_t)(oLitEnd - base)) {
+		/* offset beyond prefix */
+		if (sequence.offset > (size_t)(oLitEnd - vBase))
+			return ERROR(corruption_detected);
+		match = dictEnd + (match - base);
+		if (match + sequence.matchLength <= dictEnd) {
+			memmove(oLitEnd, match, sequence.matchLength);
+			return sequenceLength;
+		}
+		/* span extDict & currPrefixSegment */
+		{
+			size_t const length1 = dictEnd - match;
+			memmove(oLitEnd, match, length1);
+			op = oLitEnd + length1;
+			sequence.matchLength -= length1;
+			match = base;
+			if (op > oend_w || sequence.matchLength < MINMATCH) {
+				U32 i;
+				for (i = 0; i < sequence.matchLength; ++i)
+					op[i] = match[i];
+				return sequenceLength;
+			}
+		}
+	}
+	/* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
+
+	/* match within prefix */
+	if (sequence.offset < 8) {
+		/* close range match, overlap */
+		static const U32 dec32table[] = {0, 1, 2, 1, 4, 4, 4, 4};   /* added */
+		static const int dec64table[] = {8, 8, 8, 7, 8, 9, 10, 11}; /* subtracted */
+		int const sub2 = dec64table[sequence.offset];
+		op[0] = match[0];
+		op[1] = match[1];
+		op[2] = match[2];
+		op[3] = match[3];
+		match += dec32table[sequence.offset];
+		ZSTD_copy4(op + 4, match);
+		match -= sub2;
+	} else {
+		ZSTD_copy8(op, match);
+	}
+	op += 8;
+	match += 8;
+
+	if (oMatchEnd > oend - (16 - MINMATCH)) {
+		if (op < oend_w) {
+			ZSTD_wildcopy(op, match, oend_w - op);
+			match += oend_w - op;
+			op = oend_w;
+		}
+		while (op < oMatchEnd)
+			*op++ = *match++;
+	} else {
+		ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength - 8); /* works even if matchLength < 8 */
+	}
+	return sequenceLength;
+}
+
+static size_t ZSTD_decompressSequences(ZSTD_DCtx *dctx, void *dst, size_t maxDstSize, const void *seqStart, size_t seqSize)
+{
+	const BYTE *ip = (const BYTE *)seqStart;
+	const BYTE *const iend = ip + seqSize;
+	BYTE *const ostart = (BYTE * const)dst;
+	BYTE *const oend = ostart + maxDstSize;
+	BYTE *op = ostart;
+	const BYTE *litPtr = dctx->litPtr;
+	const BYTE *const litEnd = litPtr + dctx->litSize;
+	const BYTE *const base = (const BYTE *)(dctx->base);
+	const BYTE *const vBase = (const BYTE *)(dctx->vBase);
+	const BYTE *const dictEnd = (const BYTE *)(dctx->dictEnd);
+	int nbSeq;
+
+	/* Build Decoding Tables */
+	{
+		size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, seqSize);
+		if (ZSTD_isError(seqHSize))
+			return seqHSize;
+		ip += seqHSize;
+	}
+
+	/* Regen sequences */
+	if (nbSeq) {
+		seqState_t seqState;
+		dctx->fseEntropy = 1;
+		{
+			U32 i;
+			for (i = 0; i < ZSTD_REP_NUM; i++)
+				seqState.prevOffset[i] = dctx->entropy.rep[i];
+		}
+		CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend - ip), corruption_detected);
+		FSE_initDState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
+		FSE_initDState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
+		FSE_initDState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
+
+		for (; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && nbSeq;) {
+			nbSeq--;
+			{
+				seq_t const sequence = ZSTD_decodeSequence(&seqState);
+				size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litEnd, base, vBase, dictEnd);
+				if (ZSTD_isError(oneSeqSize))
+					return oneSeqSize;
+				op += oneSeqSize;
+			}
+		}
+
+		/* check if reached exact end */
+		if (nbSeq)
+			return ERROR(corruption_detected);
+		/* save reps for next block */
+		{
+			U32 i;
+			for (i = 0; i < ZSTD_REP_NUM; i++)
+				dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]);
+		}
+	}
+
+	/* last literal segment */
+	{
+		size_t const lastLLSize = litEnd - litPtr;
+		if (lastLLSize > (size_t)(oend - op))
+			return ERROR(dstSize_tooSmall);
+		memcpy(op, litPtr, lastLLSize);
+		op += lastLLSize;
+	}
+
+	return op - ostart;
+}
+
+FORCE_INLINE seq_t ZSTD_decodeSequenceLong_generic(seqState_t *seqState, int const longOffsets)
+{
+	seq_t seq;
+
+	U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
+	U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
+	U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= maxOff, by table construction */
+
+	U32 const llBits = LL_bits[llCode];
+	U32 const mlBits = ML_bits[mlCode];
+	U32 const ofBits = ofCode;
+	U32 const totalBits = llBits + mlBits + ofBits;
+
+	static const U32 LL_base[MaxLL + 1] = {0,  1,  2,  3,  4,  5,  6,  7,  8,    9,     10,    11,    12,    13,     14,     15,     16,     18,
+					       20, 22, 24, 28, 32, 40, 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000};
+
+	static const U32 ML_base[MaxML + 1] = {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,    33,     34,     35,     37,     39,     41,
+					       43, 47, 51, 59, 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803, 0x1003, 0x2003, 0x4003, 0x8003, 0x10003};
+
+	static const U32 OF_base[MaxOff + 1] = {0,       1,	1,	5,	0xD,      0x1D,      0x3D,      0x7D,      0xFD,     0x1FD,
+						0x3FD,   0x7FD,    0xFFD,    0x1FFD,   0x3FFD,   0x7FFD,    0xFFFD,    0x1FFFD,   0x3FFFD,  0x7FFFD,
+						0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD, 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD};
+
+	/* sequence */
+	{
+		size_t offset;
+		if (!ofCode)
+			offset = 0;
+		else {
+			if (longOffsets) {
+				int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN);
+				offset = OF_base[ofCode] + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
+				if (ZSTD_32bits() || extraBits)
+					BIT_reloadDStream(&seqState->DStream);
+				if (extraBits)
+					offset += BIT_readBitsFast(&seqState->DStream, extraBits);
+			} else {
+				offset = OF_base[ofCode] + BIT_readBitsFast(&seqState->DStream, ofBits); /* <=  (ZSTD_WINDOWLOG_MAX-1) bits */
+				if (ZSTD_32bits())
+					BIT_reloadDStream(&seqState->DStream);
+			}
+		}
+
+		if (ofCode <= 1) {
+			offset += (llCode == 0);
+			if (offset) {
+				size_t temp = (offset == 3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
+				temp += !temp; /* 0 is not valid; input is corrupted; force offset to 1 */
+				if (offset != 1)
+					seqState->prevOffset[2] = seqState->prevOffset[1];
+				seqState->prevOffset[1] = seqState->prevOffset[0];
+				seqState->prevOffset[0] = offset = temp;
+			} else {
+				offset = seqState->prevOffset[0];
+			}
+		} else {
+			seqState->prevOffset[2] = seqState->prevOffset[1];
+			seqState->prevOffset[1] = seqState->prevOffset[0];
+			seqState->prevOffset[0] = offset;
+		}
+		seq.offset = offset;
+	}
+
+	seq.matchLength = ML_base[mlCode] + ((mlCode > 31) ? BIT_readBitsFast(&seqState->DStream, mlBits) : 0); /* <=  16 bits */
+	if (ZSTD_32bits() && (mlBits + llBits > 24))
+		BIT_reloadDStream(&seqState->DStream);
+
+	seq.litLength = LL_base[llCode] + ((llCode > 15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <=  16 bits */
+	if (ZSTD_32bits() || (totalBits > 64 - 7 - (LLFSELog + MLFSELog + OffFSELog)))
+		BIT_reloadDStream(&seqState->DStream);
+
+	{
+		size_t const pos = seqState->pos + seq.litLength;
+		seq.match = seqState->base + pos - seq.offset; /* single memory segment */
+		if (seq.offset > pos)
+			seq.match += seqState->gotoDict; /* separate memory segment */
+		seqState->pos = pos + seq.matchLength;
+	}
+
+	/* ANS state update */
+	FSE_updateState(&seqState->stateLL, &seqState->DStream); /* <=  9 bits */
+	FSE_updateState(&seqState->stateML, &seqState->DStream); /* <=  9 bits */
+	if (ZSTD_32bits())
+		BIT_reloadDStream(&seqState->DStream);		   /* <= 18 bits */
+	FSE_updateState(&seqState->stateOffb, &seqState->DStream); /* <=  8 bits */
+
+	return seq;
+}
+
+static seq_t ZSTD_decodeSequenceLong(seqState_t *seqState, unsigned const windowSize)
+{
+	if (ZSTD_highbit32(windowSize) > STREAM_ACCUMULATOR_MIN) {
+		return ZSTD_decodeSequenceLong_generic(seqState, 1);
+	} else {
+		return ZSTD_decodeSequenceLong_generic(seqState, 0);
+	}
+}
+
+FORCE_INLINE
+size_t ZSTD_execSequenceLong(BYTE *op, BYTE *const oend, seq_t sequence, const BYTE **litPtr, const BYTE *const litLimit, const BYTE *const base,
+			     const BYTE *const vBase, const BYTE *const dictEnd)
+{
+	BYTE *const oLitEnd = op + sequence.litLength;
+	size_t const sequenceLength = sequence.litLength + sequence.matchLength;
+	BYTE *const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */
+	BYTE *const oend_w = oend - WILDCOPY_OVERLENGTH;
+	const BYTE *const iLitEnd = *litPtr + sequence.litLength;
+	const BYTE *match = sequence.match;
+
+	/* check */
+	if (oMatchEnd > oend)
+		return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
+	if (iLitEnd > litLimit)
+		return ERROR(corruption_detected); /* over-read beyond lit buffer */
+	if (oLitEnd > oend_w)
+		return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, base, vBase, dictEnd);
+
+	/* copy Literals */
+	ZSTD_copy8(op, *litPtr);
+	if (sequence.litLength > 8)
+		ZSTD_wildcopy(op + 8, (*litPtr) + 8,
+			      sequence.litLength - 8); /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
+	op = oLitEnd;
+	*litPtr = iLitEnd; /* update for next sequence */
+
+	/* copy Match */
+	if (sequence.offset > (size_t)(oLitEnd - base)) {
+		/* offset beyond prefix */
+		if (sequence.offset > (size_t)(oLitEnd - vBase))
+			return ERROR(corruption_detected);
+		if (match + sequence.matchLength <= dictEnd) {
+			memmove(oLitEnd, match, sequence.matchLength);
+			return sequenceLength;
+		}
+		/* span extDict & currPrefixSegment */
+		{
+			size_t const length1 = dictEnd - match;
+			memmove(oLitEnd, match, length1);
+			op = oLitEnd + length1;
+			sequence.matchLength -= length1;
+			match = base;
+			if (op > oend_w || sequence.matchLength < MINMATCH) {
+				U32 i;
+				for (i = 0; i < sequence.matchLength; ++i)
+					op[i] = match[i];
+				return sequenceLength;
+			}
+		}
+	}
+	/* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
+
+	/* match within prefix */
+	if (sequence.offset < 8) {
+		/* close range match, overlap */
+		static const U32 dec32table[] = {0, 1, 2, 1, 4, 4, 4, 4};   /* added */
+		static const int dec64table[] = {8, 8, 8, 7, 8, 9, 10, 11}; /* subtracted */
+		int const sub2 = dec64table[sequence.offset];
+		op[0] = match[0];
+		op[1] = match[1];
+		op[2] = match[2];
+		op[3] = match[3];
+		match += dec32table[sequence.offset];
+		ZSTD_copy4(op + 4, match);
+		match -= sub2;
+	} else {
+		ZSTD_copy8(op, match);
+	}
+	op += 8;
+	match += 8;
+
+	if (oMatchEnd > oend - (16 - MINMATCH)) {
+		if (op < oend_w) {
+			ZSTD_wildcopy(op, match, oend_w - op);
+			match += oend_w - op;
+			op = oend_w;
+		}
+		while (op < oMatchEnd)
+			*op++ = *match++;
+	} else {
+		ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength - 8); /* works even if matchLength < 8 */
+	}
+	return sequenceLength;
+}
+
+static size_t ZSTD_decompressSequencesLong(ZSTD_DCtx *dctx, void *dst, size_t maxDstSize, const void *seqStart, size_t seqSize)
+{
+	const BYTE *ip = (const BYTE *)seqStart;
+	const BYTE *const iend = ip + seqSize;
+	BYTE *const ostart = (BYTE * const)dst;
+	BYTE *const oend = ostart + maxDstSize;
+	BYTE *op = ostart;
+	const BYTE *litPtr = dctx->litPtr;
+	const BYTE *const litEnd = litPtr + dctx->litSize;
+	const BYTE *const base = (const BYTE *)(dctx->base);
+	const BYTE *const vBase = (const BYTE *)(dctx->vBase);
+	const BYTE *const dictEnd = (const BYTE *)(dctx->dictEnd);
+	unsigned const windowSize = dctx->fParams.windowSize;
+	int nbSeq;
+
+	/* Build Decoding Tables */
+	{
+		size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, seqSize);
+		if (ZSTD_isError(seqHSize))
+			return seqHSize;
+		ip += seqHSize;
+	}
+
+	/* Regen sequences */
+	if (nbSeq) {
+#define STORED_SEQS 4
+#define STOSEQ_MASK (STORED_SEQS - 1)
+#define ADVANCED_SEQS 4
+		seq_t *sequences = (seq_t *)dctx->entropy.workspace;
+		int const seqAdvance = MIN(nbSeq, ADVANCED_SEQS);
+		seqState_t seqState;
+		int seqNb;
+		ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.workspace) >= sizeof(seq_t) * STORED_SEQS);
+		dctx->fseEntropy = 1;
+		{
+			U32 i;
+			for (i = 0; i < ZSTD_REP_NUM; i++)
+				seqState.prevOffset[i] = dctx->entropy.rep[i];
+		}
+		seqState.base = base;
+		seqState.pos = (size_t)(op - base);
+		seqState.gotoDict = (uPtrDiff)dictEnd - (uPtrDiff)base; /* cast to avoid undefined behaviour */
+		CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend - ip), corruption_detected);
+		FSE_initDState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
+		FSE_initDState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
+		FSE_initDState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
+
+		/* prepare in advance */
+		for (seqNb = 0; (BIT_reloadDStream(&seqState.DStream) <= BIT_DStream_completed) && seqNb < seqAdvance; seqNb++) {
+			sequences[seqNb] = ZSTD_decodeSequenceLong(&seqState, windowSize);
+		}
+		if (seqNb < seqAdvance)
+			return ERROR(corruption_detected);
+
+		/* decode and decompress */
+		for (; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && seqNb < nbSeq; seqNb++) {
+			seq_t const sequence = ZSTD_decodeSequenceLong(&seqState, windowSize);
+			size_t const oneSeqSize =
+			    ZSTD_execSequenceLong(op, oend, sequences[(seqNb - ADVANCED_SEQS) & STOSEQ_MASK], &litPtr, litEnd, base, vBase, dictEnd);
+			if (ZSTD_isError(oneSeqSize))
+				return oneSeqSize;
+			ZSTD_PREFETCH(sequence.match);
+			sequences[seqNb & STOSEQ_MASK] = sequence;
+			op += oneSeqSize;
+		}
+		if (seqNb < nbSeq)
+			return ERROR(corruption_detected);
+
+		/* finish queue */
+		seqNb -= seqAdvance;
+		for (; seqNb < nbSeq; seqNb++) {
+			size_t const oneSeqSize = ZSTD_execSequenceLong(op, oend, sequences[seqNb & STOSEQ_MASK], &litPtr, litEnd, base, vBase, dictEnd);
+			if (ZSTD_isError(oneSeqSize))
+				return oneSeqSize;
+			op += oneSeqSize;
+		}
+
+		/* save reps for next block */
+		{
+			U32 i;
+			for (i = 0; i < ZSTD_REP_NUM; i++)
+				dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]);
+		}
+	}
+
+	/* last literal segment */
+	{
+		size_t const lastLLSize = litEnd - litPtr;
+		if (lastLLSize > (size_t)(oend - op))
+			return ERROR(dstSize_tooSmall);
+		memcpy(op, litPtr, lastLLSize);
+		op += lastLLSize;
+	}
+
+	return op - ostart;
+}
+
+static size_t ZSTD_decompressBlock_internal(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
+{ /* blockType == blockCompressed */
+	const BYTE *ip = (const BYTE *)src;
+
+	if (srcSize >= ZSTD_BLOCKSIZE_ABSOLUTEMAX)
+		return ERROR(srcSize_wrong);
+
+	/* Decode literals section */
+	{
+		size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize);
+		if (ZSTD_isError(litCSize))
+			return litCSize;
+		ip += litCSize;
+		srcSize -= litCSize;
+	}
+	if (sizeof(size_t) > 4) /* do not enable prefetching on 32-bits x86, as it's performance detrimental */
+				/* likely because of register pressure */
+				/* if that's the correct cause, then 32-bits ARM should be affected differently */
+				/* it would be good to test this on ARM real hardware, to see if prefetch version improves speed */
+		if (dctx->fParams.windowSize > (1 << 23))
+			return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize);
+	return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize);
+}
+
+static void ZSTD_checkContinuity(ZSTD_DCtx *dctx, const void *dst)
+{
+	if (dst != dctx->previousDstEnd) { /* not contiguous */
+		dctx->dictEnd = dctx->previousDstEnd;
+		dctx->vBase = (const char *)dst - ((const char *)(dctx->previousDstEnd) - (const char *)(dctx->base));
+		dctx->base = dst;
+		dctx->previousDstEnd = dst;
+	}
+}
+
+size_t ZSTD_decompressBlock(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
+{
+	size_t dSize;
+	ZSTD_checkContinuity(dctx, dst);
+	dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize);
+	dctx->previousDstEnd = (char *)dst + dSize;
+	return dSize;
+}
+
+/** ZSTD_insertBlock() :
+	insert `src` block into `dctx` history. Useful to track uncompressed blocks. */
+size_t ZSTD_insertBlock(ZSTD_DCtx *dctx, const void *blockStart, size_t blockSize)
+{
+	ZSTD_checkContinuity(dctx, blockStart);
+	dctx->previousDstEnd = (const char *)blockStart + blockSize;
+	return blockSize;
+}
+
+size_t ZSTD_generateNxBytes(void *dst, size_t dstCapacity, BYTE byte, size_t length)
+{
+	if (length > dstCapacity)
+		return ERROR(dstSize_tooSmall);
+	memset(dst, byte, length);
+	return length;
+}
+
+/** ZSTD_findFrameCompressedSize() :
+ *  compatible with legacy mode
+ *  `src` must point to the start of a ZSTD frame, ZSTD legacy frame, or skippable frame
+ *  `srcSize` must be at least as large as the frame contained
+ *  @return : the compressed size of the frame starting at `src` */
+size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize)
+{
+	if (srcSize >= ZSTD_skippableHeaderSize && (ZSTD_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
+		return ZSTD_skippableHeaderSize + ZSTD_readLE32((const BYTE *)src + 4);
+	} else {
+		const BYTE *ip = (const BYTE *)src;
+		const BYTE *const ipstart = ip;
+		size_t remainingSize = srcSize;
+		ZSTD_frameParams fParams;
+
+		size_t const headerSize = ZSTD_frameHeaderSize(ip, remainingSize);
+		if (ZSTD_isError(headerSize))
+			return headerSize;
+
+		/* Frame Header */
+		{
+			size_t const ret = ZSTD_getFrameParams(&fParams, ip, remainingSize);
+			if (ZSTD_isError(ret))
+				return ret;
+			if (ret > 0)
+				return ERROR(srcSize_wrong);
+		}
+
+		ip += headerSize;
+		remainingSize -= headerSize;
+
+		/* Loop on each block */
+		while (1) {
+			blockProperties_t blockProperties;
+			size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
+			if (ZSTD_isError(cBlockSize))
+				return cBlockSize;
+
+			if (ZSTD_blockHeaderSize + cBlockSize > remainingSize)
+				return ERROR(srcSize_wrong);
+
+			ip += ZSTD_blockHeaderSize + cBlockSize;
+			remainingSize -= ZSTD_blockHeaderSize + cBlockSize;
+
+			if (blockProperties.lastBlock)
+				break;
+		}
+
+		if (fParams.checksumFlag) { /* Frame content checksum */
+			if (remainingSize < 4)
+				return ERROR(srcSize_wrong);
+			ip += 4;
+			remainingSize -= 4;
+		}
+
+		return ip - ipstart;
+	}
+}
+
+/*! ZSTD_decompressFrame() :
+*   @dctx must be properly initialized */
+static size_t ZSTD_decompressFrame(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void **srcPtr, size_t *srcSizePtr)
+{
+	const BYTE *ip = (const BYTE *)(*srcPtr);
+	BYTE *const ostart = (BYTE * const)dst;
+	BYTE *const oend = ostart + dstCapacity;
+	BYTE *op = ostart;
+	size_t remainingSize = *srcSizePtr;
+
+	/* check */
+	if (remainingSize < ZSTD_frameHeaderSize_min + ZSTD_blockHeaderSize)
+		return ERROR(srcSize_wrong);
+
+	/* Frame Header */
+	{
+		size_t const frameHeaderSize = ZSTD_frameHeaderSize(ip, ZSTD_frameHeaderSize_prefix);
+		if (ZSTD_isError(frameHeaderSize))
+			return frameHeaderSize;
+		if (remainingSize < frameHeaderSize + ZSTD_blockHeaderSize)
+			return ERROR(srcSize_wrong);
+		CHECK_F(ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize));
+		ip += frameHeaderSize;
+		remainingSize -= frameHeaderSize;
+	}
+
+	/* Loop on each block */
+	while (1) {
+		size_t decodedSize;
+		blockProperties_t blockProperties;
+		size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
+		if (ZSTD_isError(cBlockSize))
+			return cBlockSize;
+
+		ip += ZSTD_blockHeaderSize;
+		remainingSize -= ZSTD_blockHeaderSize;
+		if (cBlockSize > remainingSize)
+			return ERROR(srcSize_wrong);
+
+		switch (blockProperties.blockType) {
+		case bt_compressed: decodedSize = ZSTD_decompressBlock_internal(dctx, op, oend - op, ip, cBlockSize); break;
+		case bt_raw: decodedSize = ZSTD_copyRawBlock(op, oend - op, ip, cBlockSize); break;
+		case bt_rle: decodedSize = ZSTD_generateNxBytes(op, oend - op, *ip, blockProperties.origSize); break;
+		case bt_reserved:
+		default: return ERROR(corruption_detected);
+		}
+
+		if (ZSTD_isError(decodedSize))
+			return decodedSize;
+		if (dctx->fParams.checksumFlag)
+			xxh64_update(&dctx->xxhState, op, decodedSize);
+		op += decodedSize;
+		ip += cBlockSize;
+		remainingSize -= cBlockSize;
+		if (blockProperties.lastBlock)
+			break;
+	}
+
+	if (dctx->fParams.checksumFlag) { /* Frame content checksum verification */
+		U32 const checkCalc = (U32)xxh64_digest(&dctx->xxhState);
+		U32 checkRead;
+		if (remainingSize < 4)
+			return ERROR(checksum_wrong);
+		checkRead = ZSTD_readLE32(ip);
+		if (checkRead != checkCalc)
+			return ERROR(checksum_wrong);
+		ip += 4;
+		remainingSize -= 4;
+	}
+
+	/* Allow caller to get size read */
+	*srcPtr = ip;
+	*srcSizePtr = remainingSize;
+	return op - ostart;
+}
+
+static const void *ZSTD_DDictDictContent(const ZSTD_DDict *ddict);
+static size_t ZSTD_DDictDictSize(const ZSTD_DDict *ddict);
+
+static size_t ZSTD_decompressMultiFrame(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const void *dict, size_t dictSize,
+					const ZSTD_DDict *ddict)
+{
+	void *const dststart = dst;
+
+	if (ddict) {
+		if (dict) {
+			/* programmer error, these two cases should be mutually exclusive */
+			return ERROR(GENERIC);
+		}
+
+		dict = ZSTD_DDictDictContent(ddict);
+		dictSize = ZSTD_DDictDictSize(ddict);
+	}
+
+	while (srcSize >= ZSTD_frameHeaderSize_prefix) {
+		U32 magicNumber;
+
+		magicNumber = ZSTD_readLE32(src);
+		if (magicNumber != ZSTD_MAGICNUMBER) {
+			if ((magicNumber & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
+				size_t skippableSize;
+				if (srcSize < ZSTD_skippableHeaderSize)
+					return ERROR(srcSize_wrong);
+				skippableSize = ZSTD_readLE32((const BYTE *)src + 4) + ZSTD_skippableHeaderSize;
+				if (srcSize < skippableSize) {
+					return ERROR(srcSize_wrong);
+				}
+
+				src = (const BYTE *)src + skippableSize;
+				srcSize -= skippableSize;
+				continue;
+			} else {
+				return ERROR(prefix_unknown);
+			}
+		}
+
+		if (ddict) {
+			/* we were called from ZSTD_decompress_usingDDict */
+			ZSTD_refDDict(dctx, ddict);
+		} else {
+			/* this will initialize correctly with no dict if dict == NULL, so
+			 * use this in all cases but ddict */
+			CHECK_F(ZSTD_decompressBegin_usingDict(dctx, dict, dictSize));
+		}
+		ZSTD_checkContinuity(dctx, dst);
+
+		{
+			const size_t res = ZSTD_decompressFrame(dctx, dst, dstCapacity, &src, &srcSize);
+			if (ZSTD_isError(res))
+				return res;
+			/* don't need to bounds check this, ZSTD_decompressFrame will have
+			 * already */
+			dst = (BYTE *)dst + res;
+			dstCapacity -= res;
+		}
+	}
+
+	if (srcSize)
+		return ERROR(srcSize_wrong); /* input not entirely consumed */
+
+	return (BYTE *)dst - (BYTE *)dststart;
+}
+
+size_t ZSTD_decompress_usingDict(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const void *dict, size_t dictSize)
+{
+	return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, dict, dictSize, NULL);
+}
+
+size_t ZSTD_decompressDCtx(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
+{
+	return ZSTD_decompress_usingDict(dctx, dst, dstCapacity, src, srcSize, NULL, 0);
+}
+
+/*-**************************************
+*   Advanced Streaming Decompression API
+*   Bufferless and synchronous
+****************************************/
+size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx *dctx) { return dctx->expected; }
+
+ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx *dctx)
+{
+	switch (dctx->stage) {
+	default: /* should not happen */
+	case ZSTDds_getFrameHeaderSize:
+	case ZSTDds_decodeFrameHeader: return ZSTDnit_frameHeader;
+	case ZSTDds_decodeBlockHeader: return ZSTDnit_blockHeader;
+	case ZSTDds_decompressBlock: return ZSTDnit_block;
+	case ZSTDds_decompressLastBlock: return ZSTDnit_lastBlock;
+	case ZSTDds_checkChecksum: return ZSTDnit_checksum;
+	case ZSTDds_decodeSkippableHeader:
+	case ZSTDds_skipFrame: return ZSTDnit_skippableFrame;
+	}
+}
+
+int ZSTD_isSkipFrame(ZSTD_DCtx *dctx) { return dctx->stage == ZSTDds_skipFrame; } /* for zbuff */
+
+/** ZSTD_decompressContinue() :
+*   @return : nb of bytes generated into `dst` (necessarily <= `dstCapacity)
+*             or an error code, which can be tested using ZSTD_isError() */
+size_t ZSTD_decompressContinue(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
+{
+	/* Sanity check */
+	if (srcSize != dctx->expected)
+		return ERROR(srcSize_wrong);
+	if (dstCapacity)
+		ZSTD_checkContinuity(dctx, dst);
+
+	switch (dctx->stage) {
+	case ZSTDds_getFrameHeaderSize:
+		if (srcSize != ZSTD_frameHeaderSize_prefix)
+			return ERROR(srcSize_wrong);					/* impossible */
+		if ((ZSTD_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */
+			memcpy(dctx->headerBuffer, src, ZSTD_frameHeaderSize_prefix);
+			dctx->expected = ZSTD_skippableHeaderSize - ZSTD_frameHeaderSize_prefix; /* magic number + skippable frame length */
+			dctx->stage = ZSTDds_decodeSkippableHeader;
+			return 0;
+		}
+		dctx->headerSize = ZSTD_frameHeaderSize(src, ZSTD_frameHeaderSize_prefix);
+		if (ZSTD_isError(dctx->headerSize))
+			return dctx->headerSize;
+		memcpy(dctx->headerBuffer, src, ZSTD_frameHeaderSize_prefix);
+		if (dctx->headerSize > ZSTD_frameHeaderSize_prefix) {
+			dctx->expected = dctx->headerSize - ZSTD_frameHeaderSize_prefix;
+			dctx->stage = ZSTDds_decodeFrameHeader;
+			return 0;
+		}
+		dctx->expected = 0; /* not necessary to copy more */
+
+	case ZSTDds_decodeFrameHeader:
+		memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, dctx->expected);
+		CHECK_F(ZSTD_decodeFrameHeader(dctx, dctx->headerBuffer, dctx->headerSize));
+		dctx->expected = ZSTD_blockHeaderSize;
+		dctx->stage = ZSTDds_decodeBlockHeader;
+		return 0;
+
+	case ZSTDds_decodeBlockHeader: {
+		blockProperties_t bp;
+		size_t const cBlockSize = ZSTD_getcBlockSize(src, ZSTD_blockHeaderSize, &bp);
+		if (ZSTD_isError(cBlockSize))
+			return cBlockSize;
+		dctx->expected = cBlockSize;
+		dctx->bType = bp.blockType;
+		dctx->rleSize = bp.origSize;
+		if (cBlockSize) {
+			dctx->stage = bp.lastBlock ? ZSTDds_decompressLastBlock : ZSTDds_decompressBlock;
+			return 0;
+		}
+		/* empty block */
+		if (bp.lastBlock) {
+			if (dctx->fParams.checksumFlag) {
+				dctx->expected = 4;
+				dctx->stage = ZSTDds_checkChecksum;
+			} else {
+				dctx->expected = 0; /* end of frame */
+				dctx->stage = ZSTDds_getFrameHeaderSize;
+			}
+		} else {
+			dctx->expected = 3; /* go directly to next header */
+			dctx->stage = ZSTDds_decodeBlockHeader;
+		}
+		return 0;
+	}
+	case ZSTDds_decompressLastBlock:
+	case ZSTDds_decompressBlock: {
+		size_t rSize;
+		switch (dctx->bType) {
+		case bt_compressed: rSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize); break;
+		case bt_raw: rSize = ZSTD_copyRawBlock(dst, dstCapacity, src, srcSize); break;
+		case bt_rle: rSize = ZSTD_setRleBlock(dst, dstCapacity, src, srcSize, dctx->rleSize); break;
+		case bt_reserved: /* should never happen */
+		default: return ERROR(corruption_detected);
+		}
+		if (ZSTD_isError(rSize))
+			return rSize;
+		if (dctx->fParams.checksumFlag)
+			xxh64_update(&dctx->xxhState, dst, rSize);
+
+		if (dctx->stage == ZSTDds_decompressLastBlock) { /* end of frame */
+			if (dctx->fParams.checksumFlag) {	/* another round for frame checksum */
+				dctx->expected = 4;
+				dctx->stage = ZSTDds_checkChecksum;
+			} else {
+				dctx->expected = 0; /* ends here */
+				dctx->stage = ZSTDds_getFrameHeaderSize;
+			}
+		} else {
+			dctx->stage = ZSTDds_decodeBlockHeader;
+			dctx->expected = ZSTD_blockHeaderSize;
+			dctx->previousDstEnd = (char *)dst + rSize;
+		}
+		return rSize;
+	}
+	case ZSTDds_checkChecksum: {
+		U32 const h32 = (U32)xxh64_digest(&dctx->xxhState);
+		U32 const check32 = ZSTD_readLE32(src); /* srcSize == 4, guaranteed by dctx->expected */
+		if (check32 != h32)
+			return ERROR(checksum_wrong);
+		dctx->expected = 0;
+		dctx->stage = ZSTDds_getFrameHeaderSize;
+		return 0;
+	}
+	case ZSTDds_decodeSkippableHeader: {
+		memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, dctx->expected);
+		dctx->expected = ZSTD_readLE32(dctx->headerBuffer + 4);
+		dctx->stage = ZSTDds_skipFrame;
+		return 0;
+	}
+	case ZSTDds_skipFrame: {
+		dctx->expected = 0;
+		dctx->stage = ZSTDds_getFrameHeaderSize;
+		return 0;
+	}
+	default:
+		return ERROR(GENERIC); /* impossible */
+	}
+}
+
+static size_t ZSTD_refDictContent(ZSTD_DCtx *dctx, const void *dict, size_t dictSize)
+{
+	dctx->dictEnd = dctx->previousDstEnd;
+	dctx->vBase = (const char *)dict - ((const char *)(dctx->previousDstEnd) - (const char *)(dctx->base));
+	dctx->base = dict;
+	dctx->previousDstEnd = (const char *)dict + dictSize;
+	return 0;
+}
+
+/* ZSTD_loadEntropy() :
+ * dict : must point at beginning of a valid zstd dictionary
+ * @return : size of entropy tables read */
+static size_t ZSTD_loadEntropy(ZSTD_entropyTables_t *entropy, const void *const dict, size_t const dictSize)
+{
+	const BYTE *dictPtr = (const BYTE *)dict;
+	const BYTE *const dictEnd = dictPtr + dictSize;
+
+	if (dictSize <= 8)
+		return ERROR(dictionary_corrupted);
+	dictPtr += 8; /* skip header = magic + dictID */
+
+	{
+		size_t const hSize = HUF_readDTableX4_wksp(entropy->hufTable, dictPtr, dictEnd - dictPtr, entropy->workspace, sizeof(entropy->workspace));
+		if (HUF_isError(hSize))
+			return ERROR(dictionary_corrupted);
+		dictPtr += hSize;
+	}
+
+	{
+		short offcodeNCount[MaxOff + 1];
+		U32 offcodeMaxValue = MaxOff, offcodeLog;
+		size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, dictEnd - dictPtr);
+		if (FSE_isError(offcodeHeaderSize))
+			return ERROR(dictionary_corrupted);
+		if (offcodeLog > OffFSELog)
+			return ERROR(dictionary_corrupted);
+		CHECK_E(FSE_buildDTable_wksp(entropy->OFTable, offcodeNCount, offcodeMaxValue, offcodeLog, entropy->workspace, sizeof(entropy->workspace)), dictionary_corrupted);
+		dictPtr += offcodeHeaderSize;
+	}
+
+	{
+		short matchlengthNCount[MaxML + 1];
+		unsigned matchlengthMaxValue = MaxML, matchlengthLog;
+		size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd - dictPtr);
+		if (FSE_isError(matchlengthHeaderSize))
+			return ERROR(dictionary_corrupted);
+		if (matchlengthLog > MLFSELog)
+			return ERROR(dictionary_corrupted);
+		CHECK_E(FSE_buildDTable_wksp(entropy->MLTable, matchlengthNCount, matchlengthMaxValue, matchlengthLog, entropy->workspace, sizeof(entropy->workspace)), dictionary_corrupted);
+		dictPtr += matchlengthHeaderSize;
+	}
+
+	{
+		short litlengthNCount[MaxLL + 1];
+		unsigned litlengthMaxValue = MaxLL, litlengthLog;
+		size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd - dictPtr);
+		if (FSE_isError(litlengthHeaderSize))
+			return ERROR(dictionary_corrupted);
+		if (litlengthLog > LLFSELog)
+			return ERROR(dictionary_corrupted);
+		CHECK_E(FSE_buildDTable_wksp(entropy->LLTable, litlengthNCount, litlengthMaxValue, litlengthLog, entropy->workspace, sizeof(entropy->workspace)), dictionary_corrupted);
+		dictPtr += litlengthHeaderSize;
+	}
+
+	if (dictPtr + 12 > dictEnd)
+		return ERROR(dictionary_corrupted);
+	{
+		int i;
+		size_t const dictContentSize = (size_t)(dictEnd - (dictPtr + 12));
+		for (i = 0; i < 3; i++) {
+			U32 const rep = ZSTD_readLE32(dictPtr);
+			dictPtr += 4;
+			if (rep == 0 || rep >= dictContentSize)
+				return ERROR(dictionary_corrupted);
+			entropy->rep[i] = rep;
+		}
+	}
+
+	return dictPtr - (const BYTE *)dict;
+}
+
+static size_t ZSTD_decompress_insertDictionary(ZSTD_DCtx *dctx, const void *dict, size_t dictSize)
+{
+	if (dictSize < 8)
+		return ZSTD_refDictContent(dctx, dict, dictSize);
+	{
+		U32 const magic = ZSTD_readLE32(dict);
+		if (magic != ZSTD_DICT_MAGIC) {
+			return ZSTD_refDictContent(dctx, dict, dictSize); /* pure content mode */
+		}
+	}
+	dctx->dictID = ZSTD_readLE32((const char *)dict + 4);
+
+	/* load entropy tables */
+	{
+		size_t const eSize = ZSTD_loadEntropy(&dctx->entropy, dict, dictSize);
+		if (ZSTD_isError(eSize))
+			return ERROR(dictionary_corrupted);
+		dict = (const char *)dict + eSize;
+		dictSize -= eSize;
+	}
+	dctx->litEntropy = dctx->fseEntropy = 1;
+
+	/* reference dictionary content */
+	return ZSTD_refDictContent(dctx, dict, dictSize);
+}
+
+size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx *dctx, const void *dict, size_t dictSize)
+{
+	CHECK_F(ZSTD_decompressBegin(dctx));
+	if (dict && dictSize)
+		CHECK_E(ZSTD_decompress_insertDictionary(dctx, dict, dictSize), dictionary_corrupted);
+	return 0;
+}
+
+/* ======   ZSTD_DDict   ====== */
+
+struct ZSTD_DDict_s {
+	void *dictBuffer;
+	const void *dictContent;
+	size_t dictSize;
+	ZSTD_entropyTables_t entropy;
+	U32 dictID;
+	U32 entropyPresent;
+	ZSTD_customMem cMem;
+}; /* typedef'd to ZSTD_DDict within "zstd.h" */
+
+size_t ZSTD_DDictWorkspaceBound(void) { return ZSTD_ALIGN(sizeof(ZSTD_stack)) + ZSTD_ALIGN(sizeof(ZSTD_DDict)); }
+
+static const void *ZSTD_DDictDictContent(const ZSTD_DDict *ddict) { return ddict->dictContent; }
+
+static size_t ZSTD_DDictDictSize(const ZSTD_DDict *ddict) { return ddict->dictSize; }
+
+static void ZSTD_refDDict(ZSTD_DCtx *dstDCtx, const ZSTD_DDict *ddict)
+{
+	ZSTD_decompressBegin(dstDCtx); /* init */
+	if (ddict) {		       /* support refDDict on NULL */
+		dstDCtx->dictID = ddict->dictID;
+		dstDCtx->base = ddict->dictContent;
+		dstDCtx->vBase = ddict->dictContent;
+		dstDCtx->dictEnd = (const BYTE *)ddict->dictContent + ddict->dictSize;
+		dstDCtx->previousDstEnd = dstDCtx->dictEnd;
+		if (ddict->entropyPresent) {
+			dstDCtx->litEntropy = 1;
+			dstDCtx->fseEntropy = 1;
+			dstDCtx->LLTptr = ddict->entropy.LLTable;
+			dstDCtx->MLTptr = ddict->entropy.MLTable;
+			dstDCtx->OFTptr = ddict->entropy.OFTable;
+			dstDCtx->HUFptr = ddict->entropy.hufTable;
+			dstDCtx->entropy.rep[0] = ddict->entropy.rep[0];
+			dstDCtx->entropy.rep[1] = ddict->entropy.rep[1];
+			dstDCtx->entropy.rep[2] = ddict->entropy.rep[2];
+		} else {
+			dstDCtx->litEntropy = 0;
+			dstDCtx->fseEntropy = 0;
+		}
+	}
+}
+
+static size_t ZSTD_loadEntropy_inDDict(ZSTD_DDict *ddict)
+{
+	ddict->dictID = 0;
+	ddict->entropyPresent = 0;
+	if (ddict->dictSize < 8)
+		return 0;
+	{
+		U32 const magic = ZSTD_readLE32(ddict->dictContent);
+		if (magic != ZSTD_DICT_MAGIC)
+			return 0; /* pure content mode */
+	}
+	ddict->dictID = ZSTD_readLE32((const char *)ddict->dictContent + 4);
+
+	/* load entropy tables */
+	CHECK_E(ZSTD_loadEntropy(&ddict->entropy, ddict->dictContent, ddict->dictSize), dictionary_corrupted);
+	ddict->entropyPresent = 1;
+	return 0;
+}
+
+static ZSTD_DDict *ZSTD_createDDict_advanced(const void *dict, size_t dictSize, unsigned byReference, ZSTD_customMem customMem)
+{
+	if (!customMem.customAlloc || !customMem.customFree)
+		return NULL;
+
+	{
+		ZSTD_DDict *const ddict = (ZSTD_DDict *)ZSTD_malloc(sizeof(ZSTD_DDict), customMem);
+		if (!ddict)
+			return NULL;
+		ddict->cMem = customMem;
+
+		if ((byReference) || (!dict) || (!dictSize)) {
+			ddict->dictBuffer = NULL;
+			ddict->dictContent = dict;
+		} else {
+			void *const internalBuffer = ZSTD_malloc(dictSize, customMem);
+			if (!internalBuffer) {
+				ZSTD_freeDDict(ddict);
+				return NULL;
+			}
+			memcpy(internalBuffer, dict, dictSize);
+			ddict->dictBuffer = internalBuffer;
+			ddict->dictContent = internalBuffer;
+		}
+		ddict->dictSize = dictSize;
+		ddict->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001); /* cover both little and big endian */
+		/* parse dictionary content */
+		{
+			size_t const errorCode = ZSTD_loadEntropy_inDDict(ddict);
+			if (ZSTD_isError(errorCode)) {
+				ZSTD_freeDDict(ddict);
+				return NULL;
+			}
+		}
+
+		return ddict;
+	}
+}
+
+/*! ZSTD_initDDict() :
+*   Create a digested dictionary, to start decompression without startup delay.
+*   `dict` content is copied inside DDict.
+*   Consequently, `dict` can be released after `ZSTD_DDict` creation */
+ZSTD_DDict *ZSTD_initDDict(const void *dict, size_t dictSize, void *workspace, size_t workspaceSize)
+{
+	ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
+	return ZSTD_createDDict_advanced(dict, dictSize, 1, stackMem);
+}
+
+size_t ZSTD_freeDDict(ZSTD_DDict *ddict)
+{
+	if (ddict == NULL)
+		return 0; /* support free on NULL */
+	{
+		ZSTD_customMem const cMem = ddict->cMem;
+		ZSTD_free(ddict->dictBuffer, cMem);
+		ZSTD_free(ddict, cMem);
+		return 0;
+	}
+}
+
+/*! ZSTD_getDictID_fromDict() :
+ *  Provides the dictID stored within dictionary.
+ *  if @return == 0, the dictionary is not conformant with Zstandard specification.
+ *  It can still be loaded, but as a content-only dictionary. */
+unsigned ZSTD_getDictID_fromDict(const void *dict, size_t dictSize)
+{
+	if (dictSize < 8)
+		return 0;
+	if (ZSTD_readLE32(dict) != ZSTD_DICT_MAGIC)
+		return 0;
+	return ZSTD_readLE32((const char *)dict + 4);
+}
+
+/*! ZSTD_getDictID_fromDDict() :
+ *  Provides the dictID of the dictionary loaded into `ddict`.
+ *  If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
+ *  Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
+unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict *ddict)
+{
+	if (ddict == NULL)
+		return 0;
+	return ZSTD_getDictID_fromDict(ddict->dictContent, ddict->dictSize);
+}
+
+/*! ZSTD_getDictID_fromFrame() :
+ *  Provides the dictID required to decompressed the frame stored within `src`.
+ *  If @return == 0, the dictID could not be decoded.
+ *  This could for one of the following reasons :
+ *  - The frame does not require a dictionary to be decoded (most common case).
+ *  - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden information.
+ *    Note : this use case also happens when using a non-conformant dictionary.
+ *  - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`).
+ *  - This is not a Zstandard frame.
+ *  When identifying the exact failure cause, it's possible to used ZSTD_getFrameParams(), which will provide a more precise error code. */
+unsigned ZSTD_getDictID_fromFrame(const void *src, size_t srcSize)
+{
+	ZSTD_frameParams zfp = {0, 0, 0, 0};
+	size_t const hError = ZSTD_getFrameParams(&zfp, src, srcSize);
+	if (ZSTD_isError(hError))
+		return 0;
+	return zfp.dictID;
+}
+
+/*! ZSTD_decompress_usingDDict() :
+*   Decompression using a pre-digested Dictionary
+*   Use dictionary without significant overhead. */
+size_t ZSTD_decompress_usingDDict(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const ZSTD_DDict *ddict)
+{
+	/* pass content and size in case legacy frames are encountered */
+	return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, NULL, 0, ddict);
+}
+
+/*=====================================
+*   Streaming decompression
+*====================================*/
+
+typedef enum { zdss_init, zdss_loadHeader, zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
+
+/* *** Resource management *** */
+struct ZSTD_DStream_s {
+	ZSTD_DCtx *dctx;
+	ZSTD_DDict *ddictLocal;
+	const ZSTD_DDict *ddict;
+	ZSTD_frameParams fParams;
+	ZSTD_dStreamStage stage;
+	char *inBuff;
+	size_t inBuffSize;
+	size_t inPos;
+	size_t maxWindowSize;
+	char *outBuff;
+	size_t outBuffSize;
+	size_t outStart;
+	size_t outEnd;
+	size_t blockSize;
+	BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX]; /* tmp buffer to store frame header */
+	size_t lhSize;
+	ZSTD_customMem customMem;
+	void *legacyContext;
+	U32 previousLegacyVersion;
+	U32 legacyVersion;
+	U32 hostageByte;
+}; /* typedef'd to ZSTD_DStream within "zstd.h" */
+
+size_t ZSTD_DStreamWorkspaceBound(size_t maxWindowSize)
+{
+	size_t const blockSize = MIN(maxWindowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
+	size_t const inBuffSize = blockSize;
+	size_t const outBuffSize = maxWindowSize + blockSize + WILDCOPY_OVERLENGTH * 2;
+	return ZSTD_DCtxWorkspaceBound() + ZSTD_ALIGN(sizeof(ZSTD_DStream)) + ZSTD_ALIGN(inBuffSize) + ZSTD_ALIGN(outBuffSize);
+}
+
+static ZSTD_DStream *ZSTD_createDStream_advanced(ZSTD_customMem customMem)
+{
+	ZSTD_DStream *zds;
+
+	if (!customMem.customAlloc || !customMem.customFree)
+		return NULL;
+
+	zds = (ZSTD_DStream *)ZSTD_malloc(sizeof(ZSTD_DStream), customMem);
+	if (zds == NULL)
+		return NULL;
+	memset(zds, 0, sizeof(ZSTD_DStream));
+	memcpy(&zds->customMem, &customMem, sizeof(ZSTD_customMem));
+	zds->dctx = ZSTD_createDCtx_advanced(customMem);
+	if (zds->dctx == NULL) {
+		ZSTD_freeDStream(zds);
+		return NULL;
+	}
+	zds->stage = zdss_init;
+	zds->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT;
+	return zds;
+}
+
+ZSTD_DStream *ZSTD_initDStream(size_t maxWindowSize, void *workspace, size_t workspaceSize)
+{
+	ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
+	ZSTD_DStream *zds = ZSTD_createDStream_advanced(stackMem);
+	if (!zds) {
+		return NULL;
+	}
+
+	zds->maxWindowSize = maxWindowSize;
+	zds->stage = zdss_loadHeader;
+	zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
+	ZSTD_freeDDict(zds->ddictLocal);
+	zds->ddictLocal = NULL;
+	zds->ddict = zds->ddictLocal;
+	zds->legacyVersion = 0;
+	zds->hostageByte = 0;
+
+	{
+		size_t const blockSize = MIN(zds->maxWindowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
+		size_t const neededOutSize = zds->maxWindowSize + blockSize + WILDCOPY_OVERLENGTH * 2;
+
+		zds->inBuff = (char *)ZSTD_malloc(blockSize, zds->customMem);
+		zds->inBuffSize = blockSize;
+		zds->outBuff = (char *)ZSTD_malloc(neededOutSize, zds->customMem);
+		zds->outBuffSize = neededOutSize;
+		if (zds->inBuff == NULL || zds->outBuff == NULL) {
+			ZSTD_freeDStream(zds);
+			return NULL;
+		}
+	}
+	return zds;
+}
+
+ZSTD_DStream *ZSTD_initDStream_usingDDict(size_t maxWindowSize, const ZSTD_DDict *ddict, void *workspace, size_t workspaceSize)
+{
+	ZSTD_DStream *zds = ZSTD_initDStream(maxWindowSize, workspace, workspaceSize);
+	if (zds) {
+		zds->ddict = ddict;
+	}
+	return zds;
+}
+
+size_t ZSTD_freeDStream(ZSTD_DStream *zds)
+{
+	if (zds == NULL)
+		return 0; /* support free on null */
+	{
+		ZSTD_customMem const cMem = zds->customMem;
+		ZSTD_freeDCtx(zds->dctx);
+		zds->dctx = NULL;
+		ZSTD_freeDDict(zds->ddictLocal);
+		zds->ddictLocal = NULL;
+		ZSTD_free(zds->inBuff, cMem);
+		zds->inBuff = NULL;
+		ZSTD_free(zds->outBuff, cMem);
+		zds->outBuff = NULL;
+		ZSTD_free(zds, cMem);
+		return 0;
+	}
+}
+
+/* *** Initialization *** */
+
+size_t ZSTD_DStreamInSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX + ZSTD_blockHeaderSize; }
+size_t ZSTD_DStreamOutSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX; }
+
+size_t ZSTD_resetDStream(ZSTD_DStream *zds)
+{
+	zds->stage = zdss_loadHeader;
+	zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
+	zds->legacyVersion = 0;
+	zds->hostageByte = 0;
+	return ZSTD_frameHeaderSize_prefix;
+}
+
+/* *****   Decompression   ***** */
+
+ZSTD_STATIC size_t ZSTD_limitCopy(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
+{
+	size_t const length = MIN(dstCapacity, srcSize);
+	memcpy(dst, src, length);
+	return length;
+}
+
+size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inBuffer *input)
+{
+	const char *const istart = (const char *)(input->src) + input->pos;
+	const char *const iend = (const char *)(input->src) + input->size;
+	const char *ip = istart;
+	char *const ostart = (char *)(output->dst) + output->pos;
+	char *const oend = (char *)(output->dst) + output->size;
+	char *op = ostart;
+	U32 someMoreWork = 1;
+
+	while (someMoreWork) {
+		switch (zds->stage) {
+		case zdss_init:
+			ZSTD_resetDStream(zds); /* transparent reset on starting decoding a new frame */
+						/* fall-through */
+
+		case zdss_loadHeader: {
+			size_t const hSize = ZSTD_getFrameParams(&zds->fParams, zds->headerBuffer, zds->lhSize);
+			if (ZSTD_isError(hSize))
+				return hSize;
+			if (hSize != 0) {				   /* need more input */
+				size_t const toLoad = hSize - zds->lhSize; /* if hSize!=0, hSize > zds->lhSize */
+				if (toLoad > (size_t)(iend - ip)) {	/* not enough input to load full header */
+					memcpy(zds->headerBuffer + zds->lhSize, ip, iend - ip);
+					zds->lhSize += iend - ip;
+					input->pos = input->size;
+					return (MAX(ZSTD_frameHeaderSize_min, hSize) - zds->lhSize) +
+					       ZSTD_blockHeaderSize; /* remaining header bytes + next block header */
+				}
+				memcpy(zds->headerBuffer + zds->lhSize, ip, toLoad);
+				zds->lhSize = hSize;
+				ip += toLoad;
+				break;
+			}
+
+			/* check for single-pass mode opportunity */
+			if (zds->fParams.frameContentSize && zds->fParams.windowSize /* skippable frame if == 0 */
+			    && (U64)(size_t)(oend - op) >= zds->fParams.frameContentSize) {
+				size_t const cSize = ZSTD_findFrameCompressedSize(istart, iend - istart);
+				if (cSize <= (size_t)(iend - istart)) {
+					size_t const decompressedSize = ZSTD_decompress_usingDDict(zds->dctx, op, oend - op, istart, cSize, zds->ddict);
+					if (ZSTD_isError(decompressedSize))
+						return decompressedSize;
+					ip = istart + cSize;
+					op += decompressedSize;
+					zds->dctx->expected = 0;
+					zds->stage = zdss_init;
+					someMoreWork = 0;
+					break;
+				}
+			}
+
+			/* Consume header */
+			ZSTD_refDDict(zds->dctx, zds->ddict);
+			{
+				size_t const h1Size = ZSTD_nextSrcSizeToDecompress(zds->dctx); /* == ZSTD_frameHeaderSize_prefix */
+				CHECK_F(ZSTD_decompressContinue(zds->dctx, NULL, 0, zds->headerBuffer, h1Size));
+				{
+					size_t const h2Size = ZSTD_nextSrcSizeToDecompress(zds->dctx);
+					CHECK_F(ZSTD_decompressContinue(zds->dctx, NULL, 0, zds->headerBuffer + h1Size, h2Size));
+				}
+			}
+
+			zds->fParams.windowSize = MAX(zds->fParams.windowSize, 1U << ZSTD_WINDOWLOG_ABSOLUTEMIN);
+			if (zds->fParams.windowSize > zds->maxWindowSize)
+				return ERROR(frameParameter_windowTooLarge);
+
+			/* Buffers are preallocated, but double check */
+			{
+				size_t const blockSize = MIN(zds->maxWindowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
+				size_t const neededOutSize = zds->maxWindowSize + blockSize + WILDCOPY_OVERLENGTH * 2;
+				if (zds->inBuffSize < blockSize) {
+					return ERROR(GENERIC);
+				}
+				if (zds->outBuffSize < neededOutSize) {
+					return ERROR(GENERIC);
+				}
+				zds->blockSize = blockSize;
+			}
+			zds->stage = zdss_read;
+		}
+		/* pass-through */
+
+		case zdss_read: {
+			size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds->dctx);
+			if (neededInSize == 0) { /* end of frame */
+				zds->stage = zdss_init;
+				someMoreWork = 0;
+				break;
+			}
+			if ((size_t)(iend - ip) >= neededInSize) { /* decode directly from src */
+				const int isSkipFrame = ZSTD_isSkipFrame(zds->dctx);
+				size_t const decodedSize = ZSTD_decompressContinue(zds->dctx, zds->outBuff + zds->outStart,
+										   (isSkipFrame ? 0 : zds->outBuffSize - zds->outStart), ip, neededInSize);
+				if (ZSTD_isError(decodedSize))
+					return decodedSize;
+				ip += neededInSize;
+				if (!decodedSize && !isSkipFrame)
+					break; /* this was just a header */
+				zds->outEnd = zds->outStart + decodedSize;
+				zds->stage = zdss_flush;
+				break;
+			}
+			if (ip == iend) {
+				someMoreWork = 0;
+				break;
+			} /* no more input */
+			zds->stage = zdss_load;
+			/* pass-through */
+		}
+
+		case zdss_load: {
+			size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds->dctx);
+			size_t const toLoad = neededInSize - zds->inPos; /* should always be <= remaining space within inBuff */
+			size_t loadedSize;
+			if (toLoad > zds->inBuffSize - zds->inPos)
+				return ERROR(corruption_detected); /* should never happen */
+			loadedSize = ZSTD_limitCopy(zds->inBuff + zds->inPos, toLoad, ip, iend - ip);
+			ip += loadedSize;
+			zds->inPos += loadedSize;
+			if (loadedSize < toLoad) {
+				someMoreWork = 0;
+				break;
+			} /* not enough input, wait for more */
+
+			/* decode loaded input */
+			{
+				const int isSkipFrame = ZSTD_isSkipFrame(zds->dctx);
+				size_t const decodedSize = ZSTD_decompressContinue(zds->dctx, zds->outBuff + zds->outStart, zds->outBuffSize - zds->outStart,
+										   zds->inBuff, neededInSize);
+				if (ZSTD_isError(decodedSize))
+					return decodedSize;
+				zds->inPos = 0; /* input is consumed */
+				if (!decodedSize && !isSkipFrame) {
+					zds->stage = zdss_read;
+					break;
+				} /* this was just a header */
+				zds->outEnd = zds->outStart + decodedSize;
+				zds->stage = zdss_flush;
+				/* pass-through */
+			}
+		}
+
+		case zdss_flush: {
+			size_t const toFlushSize = zds->outEnd - zds->outStart;
+			size_t const flushedSize = ZSTD_limitCopy(op, oend - op, zds->outBuff + zds->outStart, toFlushSize);
+			op += flushedSize;
+			zds->outStart += flushedSize;
+			if (flushedSize == toFlushSize) { /* flush completed */
+				zds->stage = zdss_read;
+				if (zds->outStart + zds->blockSize > zds->outBuffSize)
+					zds->outStart = zds->outEnd = 0;
+				break;
+			}
+			/* cannot complete flush */
+			someMoreWork = 0;
+			break;
+		}
+		default:
+			return ERROR(GENERIC); /* impossible */
+		}
+	}
+
+	/* result */
+	input->pos += (size_t)(ip - istart);
+	output->pos += (size_t)(op - ostart);
+	{
+		size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(zds->dctx);
+		if (!nextSrcSizeHint) {			    /* frame fully decoded */
+			if (zds->outEnd == zds->outStart) { /* output fully flushed */
+				if (zds->hostageByte) {
+					if (input->pos >= input->size) {
+						zds->stage = zdss_read;
+						return 1;
+					}	     /* can't release hostage (not present) */
+					input->pos++; /* release hostage */
+				}
+				return 0;
+			}
+			if (!zds->hostageByte) { /* output not fully flushed; keep last byte as hostage; will be released when all output is flushed */
+				input->pos--;    /* note : pos > 0, otherwise, impossible to finish reading last block */
+				zds->hostageByte = 1;
+			}
+			return 1;
+		}
+		nextSrcSizeHint += ZSTD_blockHeaderSize * (ZSTD_nextInputType(zds->dctx) == ZSTDnit_block); /* preload header of next block */
+		if (zds->inPos > nextSrcSizeHint)
+			return ERROR(GENERIC); /* should never happen */
+		nextSrcSizeHint -= zds->inPos; /* already loaded*/
+		return nextSrcSizeHint;
+	}
+}
+
+EXPORT_SYMBOL(ZSTD_DCtxWorkspaceBound);
+EXPORT_SYMBOL(ZSTD_initDCtx);
+EXPORT_SYMBOL(ZSTD_decompressDCtx);
+EXPORT_SYMBOL(ZSTD_decompress_usingDict);
+
+EXPORT_SYMBOL(ZSTD_DDictWorkspaceBound);
+EXPORT_SYMBOL(ZSTD_initDDict);
+EXPORT_SYMBOL(ZSTD_decompress_usingDDict);
+
+EXPORT_SYMBOL(ZSTD_DStreamWorkspaceBound);
+EXPORT_SYMBOL(ZSTD_initDStream);
+EXPORT_SYMBOL(ZSTD_initDStream_usingDDict);
+EXPORT_SYMBOL(ZSTD_resetDStream);
+EXPORT_SYMBOL(ZSTD_decompressStream);
+EXPORT_SYMBOL(ZSTD_DStreamInSize);
+EXPORT_SYMBOL(ZSTD_DStreamOutSize);
+
+EXPORT_SYMBOL(ZSTD_findFrameCompressedSize);
+EXPORT_SYMBOL(ZSTD_getFrameContentSize);
+EXPORT_SYMBOL(ZSTD_findDecompressedSize);
+
+EXPORT_SYMBOL(ZSTD_isFrame);
+EXPORT_SYMBOL(ZSTD_getDictID_fromDict);
+EXPORT_SYMBOL(ZSTD_getDictID_fromDDict);
+EXPORT_SYMBOL(ZSTD_getDictID_fromFrame);
+
+EXPORT_SYMBOL(ZSTD_getFrameParams);
+EXPORT_SYMBOL(ZSTD_decompressBegin);
+EXPORT_SYMBOL(ZSTD_decompressBegin_usingDict);
+EXPORT_SYMBOL(ZSTD_copyDCtx);
+EXPORT_SYMBOL(ZSTD_nextSrcSizeToDecompress);
+EXPORT_SYMBOL(ZSTD_decompressContinue);
+EXPORT_SYMBOL(ZSTD_nextInputType);
+
+EXPORT_SYMBOL(ZSTD_decompressBlock);
+EXPORT_SYMBOL(ZSTD_insertBlock);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("Zstd Decompressor");