1 files changed, 508 insertions, 0 deletions

diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
new file mode 100644
index 000000000..141734d25
--- /dev/null
+++ b/lib/lz4/lz4_decompress.c
@@ -0,0 +1,508 @@
+/*
+ * LZ4 - Fast LZ compression algorithm
+ * Copyright (C) 2011 - 2016, 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/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <asm/unaligned.h>
+
+/*-*****************************
+ *	Decompression functions
+ *******************************/
+/* LZ4_decompress_generic() :
+ * This generic decompression function cover all use cases.
+ * It shall be instantiated several times, using different sets of directives
+ * Note that it is important this generic function is really inlined,
+ * in order to remove useless branches during compilation optimization.
+ */
+static FORCE_INLINE int LZ4_decompress_generic(
+	 const char * const source,
+	 char * const dest,
+	 int inputSize,
+		/*
+		 * If endOnInput == endOnInputSize,
+		 * this value is the max size of Output Buffer.
+		 */
+	 int outputSize,
+	 /* endOnOutputSize, endOnInputSize */
+	 int endOnInput,
+	 /* full, partial */
+	 int partialDecoding,
+	 /* only used if partialDecoding == partial */
+	 int targetOutputSize,
+	 /* noDict, withPrefix64k, usingExtDict */
+	 int dict,
+	 /* == dest when no prefix */
+	 const BYTE * const lowPrefix,
+	 /* only if dict == usingExtDict */
+	 const BYTE * const dictStart,
+	 /* note : = 0 if noDict */
+	 const size_t dictSize
+	 )
+{
+	/* Local Variables */
+	const BYTE *ip = (const BYTE *) source;
+	const BYTE * const iend = ip + inputSize;
+
+	BYTE *op = (BYTE *) dest;
+	BYTE * const oend = op + outputSize;
+	BYTE *cpy;
+	BYTE *oexit = op + targetOutputSize;
+	const BYTE * const lowLimit = lowPrefix - dictSize;
+
+	const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize;
+	static const unsigned int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 };
+	static const int dec64table[] = { 0, 0, 0, -1, 0, 1, 2, 3 };
+
+	const int safeDecode = (endOnInput == endOnInputSize);
+	const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));
+
+	/* Special cases */
+	/* targetOutputSize too high => decode everything */
+	if ((partialDecoding) && (oexit > oend - MFLIMIT))
+		oexit = oend - MFLIMIT;
+
+	/* Empty output buffer */
+	if ((endOnInput) && (unlikely(outputSize == 0)))
+		return ((inputSize == 1) && (*ip == 0)) ? 0 : -1;
+
+	if ((!endOnInput) && (unlikely(outputSize == 0)))
+		return (*ip == 0 ? 1 : -1);
+
+	/* Main Loop : decode sequences */
+	while (1) {
+		size_t length;
+		const BYTE *match;
+		size_t offset;
+
+		/* get literal length */
+		unsigned int const token = *ip++;
+
+		length = token>>ML_BITS;
+
+		if (length == RUN_MASK) {
+			unsigned int s;
+
+			do {
+				s = *ip++;
+				length += s;
+			} while (likely(endOnInput
+				? ip < iend - RUN_MASK
+				: 1) & (s == 255));
+
+			if ((safeDecode)
+				&& unlikely(
+					(size_t)(op + length) < (size_t)(op))) {
+				/* overflow detection */
+				goto _output_error;
+			}
+			if ((safeDecode)
+				&& unlikely(
+					(size_t)(ip + length) < (size_t)(ip))) {
+				/* overflow detection */
+				goto _output_error;
+			}
+		}
+
+		/* copy literals */
+		cpy = op + length;
+		if (((endOnInput) && ((cpy > (partialDecoding ? oexit : oend - MFLIMIT))
+			|| (ip + length > iend - (2 + 1 + LASTLITERALS))))
+			|| ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
+			if (partialDecoding) {
+				if (cpy > oend) {
+					/*
+					 * Error :
+					 * write attempt beyond end of output buffer
+					 */
+					goto _output_error;
+				}
+				if ((endOnInput)
+					&& (ip + length > iend)) {
+					/*
+					 * Error :
+					 * read attempt beyond
+					 * end of input buffer
+					 */
+					goto _output_error;
+				}
+			} else {
+				if ((!endOnInput)
+					&& (cpy != oend)) {
+					/*
+					 * Error :
+					 * block decoding must
+					 * stop exactly there
+					 */
+					goto _output_error;
+				}
+				if ((endOnInput)
+					&& ((ip + length != iend)
+					|| (cpy > oend))) {
+					/*
+					 * Error :
+					 * input must be consumed
+					 */
+					goto _output_error;
+				}
+			}
+
+			memcpy(op, ip, length);
+			ip += length;
+			op += length;
+			/* Necessarily EOF, due to parsing restrictions */
+			break;
+		}
+
+		LZ4_wildCopy(op, ip, cpy);
+		ip += length;
+		op = cpy;
+
+		/* get offset */
+		offset = LZ4_readLE16(ip);
+		ip += 2;
+		match = op - offset;
+
+		if ((checkOffset) && (unlikely(match < lowLimit))) {
+			/* Error : offset outside buffers */
+			goto _output_error;
+		}
+
+		/* costs ~1%; silence an msan warning when offset == 0 */
+		LZ4_write32(op, (U32)offset);
+
+		/* get matchlength */
+		length = token & ML_MASK;
+		if (length == ML_MASK) {
+			unsigned int s;
+
+			do {
+				s = *ip++;
+
+				if ((endOnInput) && (ip > iend - LASTLITERALS))
+					goto _output_error;
+
+				length += s;
+			} while (s == 255);
+
+			if ((safeDecode)
+				&& unlikely(
+					(size_t)(op + length) < (size_t)op)) {
+				/* overflow detection */
+				goto _output_error;
+			}
+		}
+
+		length += MINMATCH;
+
+		/* check external dictionary */
+		if ((dict == usingExtDict) && (match < lowPrefix)) {
+			if (unlikely(op + length > oend - LASTLITERALS)) {
+				/* doesn't respect parsing restriction */
+				goto _output_error;
+			}
+
+			if (length <= (size_t)(lowPrefix - match)) {
+				/*
+				 * match can be copied as a single segment
+				 * from external dictionary
+				 */
+				memmove(op, dictEnd - (lowPrefix - match),
+					length);
+				op += length;
+			} else {
+				/*
+				 * match encompass external
+				 * dictionary and current block
+				 */
+				size_t const copySize = (size_t)(lowPrefix - match);
+				size_t const restSize = length - copySize;
+
+				memcpy(op, dictEnd - copySize, copySize);
+				op += copySize;
+
+				if (restSize > (size_t)(op - lowPrefix)) {
+					/* overlap copy */
+					BYTE * const endOfMatch = op + restSize;
+					const BYTE *copyFrom = lowPrefix;
+
+					while (op < endOfMatch)
+						*op++ = *copyFrom++;
+				} else {
+					memcpy(op, lowPrefix, restSize);
+					op += restSize;
+				}
+			}
+
+			continue;
+		}
+
+		/* copy match within block */
+		cpy = op + length;
+
+		if (unlikely(offset < 8)) {
+			const int dec64 = dec64table[offset];
+
+			op[0] = match[0];
+			op[1] = match[1];
+			op[2] = match[2];
+			op[3] = match[3];
+			match += dec32table[offset];
+			memcpy(op + 4, match, 4);
+			match -= dec64;
+		} else {
+			LZ4_copy8(op, match);
+			match += 8;
+		}
+
+		op += 8;
+
+		if (unlikely(cpy > oend - 12)) {
+			BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
+
+			if (cpy > oend - LASTLITERALS) {
+				/*
+				 * Error : last LASTLITERALS bytes
+				 * must be literals (uncompressed)
+				 */
+				goto _output_error;
+			}
+
+			if (op < oCopyLimit) {
+				LZ4_wildCopy(op, match, oCopyLimit);
+				match += oCopyLimit - op;
+				op = oCopyLimit;
+			}
+
+			while (op < cpy)
+				*op++ = *match++;
+		} else {
+			LZ4_copy8(op, match);
+
+			if (length > 16)
+				LZ4_wildCopy(op + 8, match + 8, cpy);
+		}
+
+		op = cpy; /* correction */
+	}
+
+	/* end of decoding */
+	if (endOnInput) {
+		/* Nb of output bytes decoded */
+		return (int) (((char *)op) - dest);
+	} else {
+		/* Nb of input bytes read */
+		return (int) (((const char *)ip) - source);
+	}
+
+	/* Overflow error detected */
+_output_error:
+	return -1;
+}
+
+int LZ4_decompress_safe(const char *source, char *dest,
+	int compressedSize, int maxDecompressedSize)
+{
+	return LZ4_decompress_generic(source, dest, compressedSize,
+		maxDecompressedSize, endOnInputSize, full, 0,
+		noDict, (BYTE *)dest, NULL, 0);
+}
+
+int LZ4_decompress_safe_partial(const char *source, char *dest,
+	int compressedSize, int targetOutputSize, int maxDecompressedSize)
+{
+	return LZ4_decompress_generic(source, dest, compressedSize,
+		maxDecompressedSize, endOnInputSize, partial,
+		targetOutputSize, noDict, (BYTE *)dest, NULL, 0);
+}
+
+int LZ4_decompress_fast(const char *source, char *dest, int originalSize)
+{
+	return LZ4_decompress_generic(source, dest, 0, originalSize,
+		endOnOutputSize, full, 0, withPrefix64k,
+		(BYTE *)(dest - 64 * KB), NULL, 64 * KB);
+}
+
+int LZ4_setStreamDecode(LZ4_streamDecode_t *LZ4_streamDecode,
+	const char *dictionary, int dictSize)
+{
+	LZ4_streamDecode_t_internal *lz4sd = (LZ4_streamDecode_t_internal *) LZ4_streamDecode;
+
+	lz4sd->prefixSize = (size_t) dictSize;
+	lz4sd->prefixEnd = (const BYTE *) dictionary + dictSize;
+	lz4sd->externalDict = NULL;
+	lz4sd->extDictSize	= 0;
+	return 1;
+}
+
+/*
+ * *_continue() :
+ * These decoding functions allow decompression of multiple blocks
+ * in "streaming" mode.
+ * Previously decoded blocks must still be available at the memory
+ * position where they were decoded.
+ * If it's not possible, save the relevant part of
+ * decoded data into a safe buffer,
+ * and indicate where it stands using LZ4_setStreamDecode()
+ */
+int LZ4_decompress_safe_continue(LZ4_streamDecode_t *LZ4_streamDecode,
+	const char *source, char *dest, int compressedSize, int maxOutputSize)
+{
+	LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse;
+	int result;
+
+	if (lz4sd->prefixEnd == (BYTE *)dest) {
+		result = LZ4_decompress_generic(source, dest,
+			compressedSize,
+			maxOutputSize,
+			endOnInputSize, full, 0,
+			usingExtDict, lz4sd->prefixEnd - lz4sd->prefixSize,
+			lz4sd->externalDict,
+			lz4sd->extDictSize);
+
+		if (result <= 0)
+			return result;
+
+		lz4sd->prefixSize += result;
+		lz4sd->prefixEnd	+= result;
+	} else {
+		lz4sd->extDictSize = lz4sd->prefixSize;
+		lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
+		result = LZ4_decompress_generic(source, dest,
+			compressedSize, maxOutputSize,
+			endOnInputSize, full, 0,
+			usingExtDict, (BYTE *)dest,
+			lz4sd->externalDict, lz4sd->extDictSize);
+		if (result <= 0)
+			return result;
+		lz4sd->prefixSize = result;
+		lz4sd->prefixEnd	= (BYTE *)dest + result;
+	}
+
+	return result;
+}
+
+int LZ4_decompress_fast_continue(LZ4_streamDecode_t *LZ4_streamDecode,
+	const char *source, char *dest, int originalSize)
+{
+	LZ4_streamDecode_t_internal *lz4sd = &LZ4_streamDecode->internal_donotuse;
+	int result;
+
+	if (lz4sd->prefixEnd == (BYTE *)dest) {
+		result = LZ4_decompress_generic(source, dest, 0, originalSize,
+			endOnOutputSize, full, 0,
+			usingExtDict,
+			lz4sd->prefixEnd - lz4sd->prefixSize,
+			lz4sd->externalDict, lz4sd->extDictSize);
+
+		if (result <= 0)
+			return result;
+
+		lz4sd->prefixSize += originalSize;
+		lz4sd->prefixEnd	+= originalSize;
+	} else {
+		lz4sd->extDictSize = lz4sd->prefixSize;
+		lz4sd->externalDict = lz4sd->prefixEnd - lz4sd->extDictSize;
+		result = LZ4_decompress_generic(source, dest, 0, originalSize,
+			endOnOutputSize, full, 0,
+			usingExtDict, (BYTE *)dest,
+			lz4sd->externalDict, lz4sd->extDictSize);
+		if (result <= 0)
+			return result;
+		lz4sd->prefixSize = originalSize;
+		lz4sd->prefixEnd	= (BYTE *)dest + originalSize;
+	}
+
+	return result;
+}
+
+/*
+ * Advanced decoding functions :
+ * *_usingDict() :
+ * These decoding functions work the same as "_continue" ones,
+ * the dictionary must be explicitly provided within parameters
+ */
+static FORCE_INLINE int LZ4_decompress_usingDict_generic(const char *source,
+	char *dest, int compressedSize, int maxOutputSize, int safe,
+	const char *dictStart, int dictSize)
+{
+	if (dictSize == 0)
+		return LZ4_decompress_generic(source, dest,
+			compressedSize, maxOutputSize, safe, full, 0,
+			noDict, (BYTE *)dest, NULL, 0);
+	if (dictStart + dictSize == dest) {
+		if (dictSize >= (int)(64 * KB - 1))
+			return LZ4_decompress_generic(source, dest,
+				compressedSize, maxOutputSize, safe, full, 0,
+				withPrefix64k, (BYTE *)dest - 64 * KB, NULL, 0);
+		return LZ4_decompress_generic(source, dest, compressedSize,
+			maxOutputSize, safe, full, 0, noDict,
+			(BYTE *)dest - dictSize, NULL, 0);
+	}
+	return LZ4_decompress_generic(source, dest, compressedSize,
+		maxOutputSize, safe, full, 0, usingExtDict,
+		(BYTE *)dest, (const BYTE *)dictStart, dictSize);
+}
+
+int LZ4_decompress_safe_usingDict(const char *source, char *dest,
+	int compressedSize, int maxOutputSize,
+	const char *dictStart, int dictSize)
+{
+	return LZ4_decompress_usingDict_generic(source, dest,
+		compressedSize, maxOutputSize, 1, dictStart, dictSize);
+}
+
+int LZ4_decompress_fast_usingDict(const char *source, char *dest,
+	int originalSize, const char *dictStart, int dictSize)
+{
+	return LZ4_decompress_usingDict_generic(source, dest, 0,
+		originalSize, 0, dictStart, dictSize);
+}
+
+#ifndef STATIC
+EXPORT_SYMBOL(LZ4_decompress_safe);
+EXPORT_SYMBOL(LZ4_decompress_safe_partial);
+EXPORT_SYMBOL(LZ4_decompress_fast);
+EXPORT_SYMBOL(LZ4_setStreamDecode);
+EXPORT_SYMBOL(LZ4_decompress_safe_continue);
+EXPORT_SYMBOL(LZ4_decompress_fast_continue);
+EXPORT_SYMBOL(LZ4_decompress_safe_usingDict);
+EXPORT_SYMBOL(LZ4_decompress_fast_usingDict);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("LZ4 decompressor");
+#endif