Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 768 insertions, 0 deletions

diff --git a/lib/lz4/lz4hc_compress.c b/lib/lz4/lz4hc_compress.c
new file mode 100644
index 000000000..e7ac8694b
--- /dev/null
+++ b/lib/lz4/lz4hc_compress.c
@@ -0,0 +1,768 @@
+/*
+ * LZ4 HC - High Compression Mode of LZ4
+ * Copyright (C) 2011-2015, Yann Collet.
+ *
+ * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd - license.php)
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *	* Redistributions of source code must retain the above copyright
+ *	  notice, this list of conditions and the following disclaimer.
+ *	* Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * You can contact the author at :
+ *	- LZ4 homepage : http://www.lz4.org
+ *	- LZ4 source repository : https://github.com/lz4/lz4
+ *
+ *	Changed for kernel usage by:
+ *	Sven Schmidt <4sschmid@informatik.uni-hamburg.de>
+ */
+
+/*-************************************
+ *	Dependencies
+ **************************************/
+#include <linux/lz4.h>
+#include "lz4defs.h"
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/string.h> /* memset */
+
+/* *************************************
+ *	Local Constants and types
+ ***************************************/
+
+#define OPTIMAL_ML (int)((ML_MASK - 1) + MINMATCH)
+
+#define HASH_FUNCTION(i)	(((i) * 2654435761U) \
+	>> ((MINMATCH*8) - LZ4HC_HASH_LOG))
+#define DELTANEXTU16(p)	chainTable[(U16)(p)] /* faster */
+
+static U32 LZ4HC_hashPtr(const void *ptr)
+{
+	return HASH_FUNCTION(LZ4_read32(ptr));
+}
+
+/**************************************
+ *	HC Compression
+ **************************************/
+static void LZ4HC_init(LZ4HC_CCtx_internal *hc4, const BYTE *start)
+{
+	memset((void *)hc4->hashTable, 0, sizeof(hc4->hashTable));
+	memset(hc4->chainTable, 0xFF, sizeof(hc4->chainTable));
+	hc4->nextToUpdate = 64 * KB;
+	hc4->base = start - 64 * KB;
+	hc4->end = start;
+	hc4->dictBase = start - 64 * KB;
+	hc4->dictLimit = 64 * KB;
+	hc4->lowLimit = 64 * KB;
+}
+
+/* Update chains up to ip (excluded) */
+static FORCE_INLINE void LZ4HC_Insert(LZ4HC_CCtx_internal *hc4,
+	const BYTE *ip)
+{
+	U16 * const chainTable = hc4->chainTable;
+	U32 * const hashTable	= hc4->hashTable;
+	const BYTE * const base = hc4->base;
+	U32 const target = (U32)(ip - base);
+	U32 idx = hc4->nextToUpdate;
+
+	while (idx < target) {
+		U32 const h = LZ4HC_hashPtr(base + idx);
+		size_t delta = idx - hashTable[h];
+
+		if (delta > MAX_DISTANCE)
+			delta = MAX_DISTANCE;
+
+		DELTANEXTU16(idx) = (U16)delta;
+
+		hashTable[h] = idx;
+		idx++;
+	}
+
+	hc4->nextToUpdate = target;
+}
+
+static FORCE_INLINE int LZ4HC_InsertAndFindBestMatch(
+	LZ4HC_CCtx_internal *hc4, /* Index table will be updated */
+	const BYTE *ip,
+	const BYTE * const iLimit,
+	const BYTE **matchpos,
+	const int maxNbAttempts)
+{
+	U16 * const chainTable = hc4->chainTable;
+	U32 * const HashTable = hc4->hashTable;
+	const BYTE * const base = hc4->base;
+	const BYTE * const dictBase = hc4->dictBase;
+	const U32 dictLimit = hc4->dictLimit;
+	const U32 lowLimit = (hc4->lowLimit + 64 * KB > (U32)(ip - base))
+		? hc4->lowLimit
+		: (U32)(ip - base) - (64 * KB - 1);
+	U32 matchIndex;
+	int nbAttempts = maxNbAttempts;
+	size_t ml = 0;
+
+	/* HC4 match finder */
+	LZ4HC_Insert(hc4, ip);
+	matchIndex = HashTable[LZ4HC_hashPtr(ip)];
+
+	while ((matchIndex >= lowLimit)
+		&& (nbAttempts)) {
+		nbAttempts--;
+		if (matchIndex >= dictLimit) {
+			const BYTE * const match = base + matchIndex;
+
+			if (*(match + ml) == *(ip + ml)
+				&& (LZ4_read32(match) == LZ4_read32(ip))) {
+				size_t const mlt = LZ4_count(ip + MINMATCH,
+					match + MINMATCH, iLimit) + MINMATCH;
+
+				if (mlt > ml) {
+					ml = mlt;
+					*matchpos = match;
+				}
+			}
+		} else {
+			const BYTE * const match = dictBase + matchIndex;
+
+			if (LZ4_read32(match) == LZ4_read32(ip)) {
+				size_t mlt;
+				const BYTE *vLimit = ip
+					+ (dictLimit - matchIndex);
+
+				if (vLimit > iLimit)
+					vLimit = iLimit;
+				mlt = LZ4_count(ip + MINMATCH,
+					match + MINMATCH, vLimit) + MINMATCH;
+				if ((ip + mlt == vLimit)
+					&& (vLimit < iLimit))
+					mlt += LZ4_count(ip + mlt,
+						base + dictLimit,
+						iLimit);
+				if (mlt > ml) {
+					/* virtual matchpos */
+					ml = mlt;
+					*matchpos = base + matchIndex;
+				}
+			}
+		}
+		matchIndex -= DELTANEXTU16(matchIndex);
+	}
+
+	return (int)ml;
+}
+
+static FORCE_INLINE int LZ4HC_InsertAndGetWiderMatch(
+	LZ4HC_CCtx_internal *hc4,
+	const BYTE * const ip,
+	const BYTE * const iLowLimit,
+	const BYTE * const iHighLimit,
+	int longest,
+	const BYTE **matchpos,
+	const BYTE **startpos,
+	const int maxNbAttempts)
+{
+	U16 * const chainTable = hc4->chainTable;
+	U32 * const HashTable = hc4->hashTable;
+	const BYTE * const base = hc4->base;
+	const U32 dictLimit = hc4->dictLimit;
+	const BYTE * const lowPrefixPtr = base + dictLimit;
+	const U32 lowLimit = (hc4->lowLimit + 64 * KB > (U32)(ip - base))
+		? hc4->lowLimit
+		: (U32)(ip - base) - (64 * KB - 1);
+	const BYTE * const dictBase = hc4->dictBase;
+	U32 matchIndex;
+	int nbAttempts = maxNbAttempts;
+	int delta = (int)(ip - iLowLimit);
+
+	/* First Match */
+	LZ4HC_Insert(hc4, ip);
+	matchIndex = HashTable[LZ4HC_hashPtr(ip)];
+
+	while ((matchIndex >= lowLimit)
+		&& (nbAttempts)) {
+		nbAttempts--;
+		if (matchIndex >= dictLimit) {
+			const BYTE *matchPtr = base + matchIndex;
+
+			if (*(iLowLimit + longest)
+				== *(matchPtr - delta + longest)) {
+				if (LZ4_read32(matchPtr) == LZ4_read32(ip)) {
+					int mlt = MINMATCH + LZ4_count(
+						ip + MINMATCH,
+						matchPtr + MINMATCH,
+						iHighLimit);
+					int back = 0;
+
+					while ((ip + back > iLowLimit)
+						&& (matchPtr + back > lowPrefixPtr)
+						&& (ip[back - 1] == matchPtr[back - 1]))
+						back--;
+
+					mlt -= back;
+
+					if (mlt > longest) {
+						longest = (int)mlt;
+						*matchpos = matchPtr + back;
+						*startpos = ip + back;
+					}
+				}
+			}
+		} else {
+			const BYTE * const matchPtr = dictBase + matchIndex;
+
+			if (LZ4_read32(matchPtr) == LZ4_read32(ip)) {
+				size_t mlt;
+				int back = 0;
+				const BYTE *vLimit = ip + (dictLimit - matchIndex);
+
+				if (vLimit > iHighLimit)
+					vLimit = iHighLimit;
+
+				mlt = LZ4_count(ip + MINMATCH,
+					matchPtr + MINMATCH, vLimit) + MINMATCH;
+
+				if ((ip + mlt == vLimit) && (vLimit < iHighLimit))
+					mlt += LZ4_count(ip + mlt, base + dictLimit,
+						iHighLimit);
+				while ((ip + back > iLowLimit)
+					&& (matchIndex + back > lowLimit)
+					&& (ip[back - 1] == matchPtr[back - 1]))
+					back--;
+
+				mlt -= back;
+
+				if ((int)mlt > longest) {
+					longest = (int)mlt;
+					*matchpos = base + matchIndex + back;
+					*startpos = ip + back;
+				}
+			}
+		}
+
+		matchIndex -= DELTANEXTU16(matchIndex);
+	}
+
+	return longest;
+}
+
+static FORCE_INLINE int LZ4HC_encodeSequence(
+	const BYTE **ip,
+	BYTE **op,
+	const BYTE **anchor,
+	int matchLength,
+	const BYTE * const match,
+	limitedOutput_directive limitedOutputBuffer,
+	BYTE *oend)
+{
+	int length;
+	BYTE *token;
+
+	/* Encode Literal length */
+	length = (int)(*ip - *anchor);
+	token = (*op)++;
+
+	if ((limitedOutputBuffer)
+		&& ((*op + (length>>8)
+			+ length + (2 + 1 + LASTLITERALS)) > oend)) {
+		/* Check output limit */
+		return 1;
+	}
+	if (length >= (int)RUN_MASK) {
+		int len;
+
+		*token = (RUN_MASK<<ML_BITS);
+		len = length - RUN_MASK;
+		for (; len > 254 ; len -= 255)
+			*(*op)++ = 255;
+		*(*op)++ = (BYTE)len;
+	} else
+		*token = (BYTE)(length<<ML_BITS);
+
+	/* Copy Literals */
+	LZ4_wildCopy(*op, *anchor, (*op) + length);
+	*op += length;
+
+	/* Encode Offset */
+	LZ4_writeLE16(*op, (U16)(*ip - match));
+	*op += 2;
+
+	/* Encode MatchLength */
+	length = (int)(matchLength - MINMATCH);
+
+	if ((limitedOutputBuffer)
+		&& (*op + (length>>8)
+			+ (1 + LASTLITERALS) > oend)) {
+		/* Check output limit */
+		return 1;
+	}
+
+	if (length >= (int)ML_MASK) {
+		*token += ML_MASK;
+		length -= ML_MASK;
+
+		for (; length > 509 ; length -= 510) {
+			*(*op)++ = 255;
+			*(*op)++ = 255;
+		}
+
+		if (length > 254) {
+			length -= 255;
+			*(*op)++ = 255;
+		}
+
+		*(*op)++ = (BYTE)length;
+	} else
+		*token += (BYTE)(length);
+
+	/* Prepare next loop */
+	*ip += matchLength;
+	*anchor = *ip;
+
+	return 0;
+}
+
+static int LZ4HC_compress_generic(
+	LZ4HC_CCtx_internal *const ctx,
+	const char * const source,
+	char * const dest,
+	int const inputSize,
+	int const maxOutputSize,
+	int compressionLevel,
+	limitedOutput_directive limit
+	)
+{
+	const BYTE *ip = (const BYTE *) source;
+	const BYTE *anchor = ip;
+	const BYTE * const iend = ip + inputSize;
+	const BYTE * const mflimit = iend - MFLIMIT;
+	const BYTE * const matchlimit = (iend - LASTLITERALS);
+
+	BYTE *op = (BYTE *) dest;
+	BYTE * const oend = op + maxOutputSize;
+
+	unsigned int maxNbAttempts;
+	int ml, ml2, ml3, ml0;
+	const BYTE *ref = NULL;
+	const BYTE *start2 = NULL;
+	const BYTE *ref2 = NULL;
+	const BYTE *start3 = NULL;
+	const BYTE *ref3 = NULL;
+	const BYTE *start0;
+	const BYTE *ref0;
+
+	/* init */
+	if (compressionLevel > LZ4HC_MAX_CLEVEL)
+		compressionLevel = LZ4HC_MAX_CLEVEL;
+	if (compressionLevel < 1)
+		compressionLevel = LZ4HC_DEFAULT_CLEVEL;
+	maxNbAttempts = 1 << (compressionLevel - 1);
+	ctx->end += inputSize;
+
+	ip++;
+
+	/* Main Loop */
+	while (ip < mflimit) {
+		ml = LZ4HC_InsertAndFindBestMatch(ctx, ip,
+			matchlimit, (&ref), maxNbAttempts);
+		if (!ml) {
+			ip++;
+			continue;
+		}
+
+		/* saved, in case we would skip too much */
+		start0 = ip;
+		ref0 = ref;
+		ml0 = ml;
+
+_Search2:
+		if (ip + ml < mflimit)
+			ml2 = LZ4HC_InsertAndGetWiderMatch(ctx,
+				ip + ml - 2, ip + 0,
+				matchlimit, ml, &ref2,
+				&start2, maxNbAttempts);
+		else
+			ml2 = ml;
+
+		if (ml2 == ml) {
+			/* No better match */
+			if (LZ4HC_encodeSequence(&ip, &op,
+				&anchor, ml, ref, limit, oend))
+				return 0;
+			continue;
+		}
+
+		if (start0 < ip) {
+			if (start2 < ip + ml0) {
+				/* empirical */
+				ip = start0;
+				ref = ref0;
+				ml = ml0;
+			}
+		}
+
+		/* Here, start0 == ip */
+		if ((start2 - ip) < 3) {
+			/* First Match too small : removed */
+			ml = ml2;
+			ip = start2;
+			ref = ref2;
+			goto _Search2;
+		}
+
+_Search3:
+		/*
+		* Currently we have :
+		* ml2 > ml1, and
+		* ip1 + 3 <= ip2 (usually < ip1 + ml1)
+		*/
+		if ((start2 - ip) < OPTIMAL_ML) {
+			int correction;
+			int new_ml = ml;
+
+			if (new_ml > OPTIMAL_ML)
+				new_ml = OPTIMAL_ML;
+			if (ip + new_ml > start2 + ml2 - MINMATCH)
+				new_ml = (int)(start2 - ip) + ml2 - MINMATCH;
+
+			correction = new_ml - (int)(start2 - ip);
+
+			if (correction > 0) {
+				start2 += correction;
+				ref2 += correction;
+				ml2 -= correction;
+			}
+		}
+		/*
+		 * Now, we have start2 = ip + new_ml,
+		 * with new_ml = min(ml, OPTIMAL_ML = 18)
+		 */
+
+		if (start2 + ml2 < mflimit)
+			ml3 = LZ4HC_InsertAndGetWiderMatch(ctx,
+				start2 + ml2 - 3, start2,
+				matchlimit, ml2, &ref3, &start3,
+				maxNbAttempts);
+		else
+			ml3 = ml2;
+
+		if (ml3 == ml2) {
+			/* No better match : 2 sequences to encode */
+			/* ip & ref are known; Now for ml */
+			if (start2 < ip + ml)
+				ml = (int)(start2 - ip);
+			/* Now, encode 2 sequences */
+			if (LZ4HC_encodeSequence(&ip, &op, &anchor,
+				ml, ref, limit, oend))
+				return 0;
+			ip = start2;
+			if (LZ4HC_encodeSequence(&ip, &op, &anchor,
+				ml2, ref2, limit, oend))
+				return 0;
+			continue;
+		}
+
+		if (start3 < ip + ml + 3) {
+			/* Not enough space for match 2 : remove it */
+			if (start3 >= (ip + ml)) {
+				/* can write Seq1 immediately
+				 * ==> Seq2 is removed,
+				 * so Seq3 becomes Seq1
+				 */
+				if (start2 < ip + ml) {
+					int correction = (int)(ip + ml - start2);
+
+					start2 += correction;
+					ref2 += correction;
+					ml2 -= correction;
+					if (ml2 < MINMATCH) {
+						start2 = start3;
+						ref2 = ref3;
+						ml2 = ml3;
+					}
+				}
+
+				if (LZ4HC_encodeSequence(&ip, &op, &anchor,
+					ml, ref, limit, oend))
+					return 0;
+				ip = start3;
+				ref = ref3;
+				ml = ml3;
+
+				start0 = start2;
+				ref0 = ref2;
+				ml0 = ml2;
+				goto _Search2;
+			}
+
+			start2 = start3;
+			ref2 = ref3;
+			ml2 = ml3;
+			goto _Search3;
+		}
+
+		/*
+		* OK, now we have 3 ascending matches;
+		* let's write at least the first one
+		* ip & ref are known; Now for ml
+		*/
+		if (start2 < ip + ml) {
+			if ((start2 - ip) < (int)ML_MASK) {
+				int correction;
+
+				if (ml > OPTIMAL_ML)
+					ml = OPTIMAL_ML;
+				if (ip + ml > start2 + ml2 - MINMATCH)
+					ml = (int)(start2 - ip) + ml2 - MINMATCH;
+				correction = ml - (int)(start2 - ip);
+				if (correction > 0) {
+					start2 += correction;
+					ref2 += correction;
+					ml2 -= correction;
+				}
+			} else
+				ml = (int)(start2 - ip);
+		}
+		if (LZ4HC_encodeSequence(&ip, &op, &anchor, ml,
+			ref, limit, oend))
+			return 0;
+
+		ip = start2;
+		ref = ref2;
+		ml = ml2;
+
+		start2 = start3;
+		ref2 = ref3;
+		ml2 = ml3;
+
+		goto _Search3;
+	}
+
+	/* Encode Last Literals */
+	{
+		int lastRun = (int)(iend - anchor);
+
+		if ((limit)
+			&& (((char *)op - dest) + lastRun + 1
+				+ ((lastRun + 255 - RUN_MASK)/255)
+					> (U32)maxOutputSize)) {
+			/* Check output limit */
+			return 0;
+		}
+		if (lastRun >= (int)RUN_MASK) {
+			*op++ = (RUN_MASK<<ML_BITS);
+			lastRun -= RUN_MASK;
+			for (; lastRun > 254 ; lastRun -= 255)
+				*op++ = 255;
+			*op++ = (BYTE) lastRun;
+		} else
+			*op++ = (BYTE)(lastRun<<ML_BITS);
+		LZ4_memcpy(op, anchor, iend - anchor);
+		op += iend - anchor;
+	}
+
+	/* End */
+	return (int) (((char *)op) - dest);
+}
+
+static int LZ4_compress_HC_extStateHC(
+	void *state,
+	const char *src,
+	char *dst,
+	int srcSize,
+	int maxDstSize,
+	int compressionLevel)
+{
+	LZ4HC_CCtx_internal *ctx = &((LZ4_streamHC_t *)state)->internal_donotuse;
+
+	if (((size_t)(state)&(sizeof(void *) - 1)) != 0) {
+		/* Error : state is not aligned
+		 * for pointers (32 or 64 bits)
+		 */
+		return 0;
+	}
+
+	LZ4HC_init(ctx, (const BYTE *)src);
+
+	if (maxDstSize < LZ4_compressBound(srcSize))
+		return LZ4HC_compress_generic(ctx, src, dst,
+			srcSize, maxDstSize, compressionLevel, limitedOutput);
+	else
+		return LZ4HC_compress_generic(ctx, src, dst,
+			srcSize, maxDstSize, compressionLevel, noLimit);
+}
+
+int LZ4_compress_HC(const char *src, char *dst, int srcSize,
+	int maxDstSize, int compressionLevel, void *wrkmem)
+{
+	return LZ4_compress_HC_extStateHC(wrkmem, src, dst,
+		srcSize, maxDstSize, compressionLevel);
+}
+EXPORT_SYMBOL(LZ4_compress_HC);
+
+/**************************************
+ *	Streaming Functions
+ **************************************/
+void LZ4_resetStreamHC(LZ4_streamHC_t *LZ4_streamHCPtr, int compressionLevel)
+{
+	LZ4_streamHCPtr->internal_donotuse.base = NULL;
+	LZ4_streamHCPtr->internal_donotuse.compressionLevel = (unsigned int)compressionLevel;
+}
+
+int LZ4_loadDictHC(LZ4_streamHC_t *LZ4_streamHCPtr,
+	const char *dictionary,
+	int dictSize)
+{
+	LZ4HC_CCtx_internal *ctxPtr = &LZ4_streamHCPtr->internal_donotuse;
+
+	if (dictSize > 64 * KB) {
+		dictionary += dictSize - 64 * KB;
+		dictSize = 64 * KB;
+	}
+	LZ4HC_init(ctxPtr, (const BYTE *)dictionary);
+	if (dictSize >= 4)
+		LZ4HC_Insert(ctxPtr, (const BYTE *)dictionary + (dictSize - 3));
+	ctxPtr->end = (const BYTE *)dictionary + dictSize;
+	return dictSize;
+}
+EXPORT_SYMBOL(LZ4_loadDictHC);
+
+/* compression */
+
+static void LZ4HC_setExternalDict(
+	LZ4HC_CCtx_internal *ctxPtr,
+	const BYTE *newBlock)
+{
+	if (ctxPtr->end >= ctxPtr->base + 4) {
+		/* Referencing remaining dictionary content */
+		LZ4HC_Insert(ctxPtr, ctxPtr->end - 3);
+	}
+
+	/*
+	 * Only one memory segment for extDict,
+	 * so any previous extDict is lost at this stage
+	 */
+	ctxPtr->lowLimit	= ctxPtr->dictLimit;
+	ctxPtr->dictLimit = (U32)(ctxPtr->end - ctxPtr->base);
+	ctxPtr->dictBase	= ctxPtr->base;
+	ctxPtr->base = newBlock - ctxPtr->dictLimit;
+	ctxPtr->end	= newBlock;
+	/* match referencing will resume from there */
+	ctxPtr->nextToUpdate = ctxPtr->dictLimit;
+}
+
+static int LZ4_compressHC_continue_generic(
+	LZ4_streamHC_t *LZ4_streamHCPtr,
+	const char *source,
+	char *dest,
+	int inputSize,
+	int maxOutputSize,
+	limitedOutput_directive limit)
+{
+	LZ4HC_CCtx_internal *ctxPtr = &LZ4_streamHCPtr->internal_donotuse;
+
+	/* auto - init if forgotten */
+	if (ctxPtr->base == NULL)
+		LZ4HC_init(ctxPtr, (const BYTE *) source);
+
+	/* Check overflow */
+	if ((size_t)(ctxPtr->end - ctxPtr->base) > 2 * GB) {
+		size_t dictSize = (size_t)(ctxPtr->end - ctxPtr->base)
+			- ctxPtr->dictLimit;
+		if (dictSize > 64 * KB)
+			dictSize = 64 * KB;
+		LZ4_loadDictHC(LZ4_streamHCPtr,
+			(const char *)(ctxPtr->end) - dictSize, (int)dictSize);
+	}
+
+	/* Check if blocks follow each other */
+	if ((const BYTE *)source != ctxPtr->end)
+		LZ4HC_setExternalDict(ctxPtr, (const BYTE *)source);
+
+	/* Check overlapping input/dictionary space */
+	{
+		const BYTE *sourceEnd = (const BYTE *) source + inputSize;
+		const BYTE * const dictBegin = ctxPtr->dictBase + ctxPtr->lowLimit;
+		const BYTE * const dictEnd = ctxPtr->dictBase + ctxPtr->dictLimit;
+
+		if ((sourceEnd > dictBegin)
+			&& ((const BYTE *)source < dictEnd)) {
+			if (sourceEnd > dictEnd)
+				sourceEnd = dictEnd;
+			ctxPtr->lowLimit = (U32)(sourceEnd - ctxPtr->dictBase);
+
+			if (ctxPtr->dictLimit - ctxPtr->lowLimit < 4)
+				ctxPtr->lowLimit = ctxPtr->dictLimit;
+		}
+	}
+
+	return LZ4HC_compress_generic(ctxPtr, source, dest,
+		inputSize, maxOutputSize, ctxPtr->compressionLevel, limit);
+}
+
+int LZ4_compress_HC_continue(
+	LZ4_streamHC_t *LZ4_streamHCPtr,
+	const char *source,
+	char *dest,
+	int inputSize,
+	int maxOutputSize)
+{
+	if (maxOutputSize < LZ4_compressBound(inputSize))
+		return LZ4_compressHC_continue_generic(LZ4_streamHCPtr,
+			source, dest, inputSize, maxOutputSize, limitedOutput);
+	else
+		return LZ4_compressHC_continue_generic(LZ4_streamHCPtr,
+			source, dest, inputSize, maxOutputSize, noLimit);
+}
+EXPORT_SYMBOL(LZ4_compress_HC_continue);
+
+/* dictionary saving */
+
+int LZ4_saveDictHC(
+	LZ4_streamHC_t *LZ4_streamHCPtr,
+	char *safeBuffer,
+	int dictSize)
+{
+	LZ4HC_CCtx_internal *const streamPtr = &LZ4_streamHCPtr->internal_donotuse;
+	int const prefixSize = (int)(streamPtr->end
+		- (streamPtr->base + streamPtr->dictLimit));
+
+	if (dictSize > 64 * KB)
+		dictSize = 64 * KB;
+	if (dictSize < 4)
+		dictSize = 0;
+	if (dictSize > prefixSize)
+		dictSize = prefixSize;
+
+	memmove(safeBuffer, streamPtr->end - dictSize, dictSize);
+
+	{
+		U32 const endIndex = (U32)(streamPtr->end - streamPtr->base);
+
+		streamPtr->end = (const BYTE *)safeBuffer + dictSize;
+		streamPtr->base = streamPtr->end - endIndex;
+		streamPtr->dictLimit = endIndex - dictSize;
+		streamPtr->lowLimit = endIndex - dictSize;
+
+		if (streamPtr->nextToUpdate < streamPtr->dictLimit)
+			streamPtr->nextToUpdate = streamPtr->dictLimit;
+	}
+	return dictSize;
+}
+EXPORT_SYMBOL(LZ4_saveDictHC);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("LZ4 HC compressor");