[mirror_ubuntu-artful-kernel.git] / lib / lz4 / lz4_decompress.c

/*
 * LZ4 Decompressor for Linux kernel
 *
 * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
 *
 * Based on LZ4 implementation by Yann Collet.
 *
 * LZ4 - Fast LZ compression algorithm
 * Copyright (C) 2011-2012, 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://fastcompression.blogspot.com/p/lz4.html
 *  - LZ4 source repository : http://code.google.com/p/lz4/
 */

#ifndef STATIC
#include <linux/module.h>
#include <linux/kernel.h>
#endif
#include <linux/lz4.h>

#include <asm/unaligned.h>

#include "lz4defs.h"

static const int dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
#if LZ4_ARCH64
static const int dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
#endif

static int lz4_uncompress(const char *source, char *dest, int osize)
{
	const BYTE *ip = (const BYTE *) source;
	const BYTE *ref;
	BYTE *op = (BYTE *) dest;
	BYTE * const oend = op + osize;
	BYTE *cpy;
	unsigned token;
	size_t length;

	while (1) {

		/* get runlength */
		token = *ip++;
		length = (token >> ML_BITS);
		if (length == RUN_MASK) {
			size_t len;

			len = *ip++;
			for (; len == 255; length += 255)
				len = *ip++;
			if (unlikely(length > (size_t)(length + len)))
				goto _output_error;
			length += len;
		}

		/* copy literals */
		cpy = op + length;
		if (unlikely(cpy > oend - COPYLENGTH)) {
			/*
			 * Error: not enough place for another match
			 * (min 4) + 5 literals
			 */
			if (cpy != oend)
				goto _output_error;

			memcpy(op, ip, length);
			ip += length;
			break; /* EOF */
		}
		LZ4_WILDCOPY(ip, op, cpy);
		ip -= (op - cpy);
		op = cpy;

		/* get offset */
		LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
		ip += 2;

		/* Error: offset create reference outside destination buffer */
		if (unlikely(ref < (BYTE *const) dest))
			goto _output_error;

		/* get matchlength */
		length = token & ML_MASK;
		if (length == ML_MASK) {
			for (; *ip == 255; length += 255)
				ip++;
			if (unlikely(length > (size_t)(length + *ip)))
				goto _output_error;
			length += *ip++;
		}

		/* copy repeated sequence */
		if (unlikely((op - ref) < STEPSIZE)) {
#if LZ4_ARCH64
			int dec64 = dec64table[op - ref];
#else
			const int dec64 = 0;
#endif
			op[0] = ref[0];
			op[1] = ref[1];
			op[2] = ref[2];
			op[3] = ref[3];
			op += 4;
			ref += 4;
			ref -= dec32table[op-ref];
			PUT4(ref, op);
			op += STEPSIZE - 4;
			ref -= dec64;
		} else {
			LZ4_COPYSTEP(ref, op);
		}
		cpy = op + length - (STEPSIZE - 4);
		if (cpy > (oend - COPYLENGTH)) {

			/* Error: request to write beyond destination buffer */
			if (cpy > oend)
				goto _output_error;
			if ((ref + COPYLENGTH) > oend ||
					(op + COPYLENGTH) > oend)
				goto _output_error;
			LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
			while (op < cpy)
				*op++ = *ref++;
			op = cpy;
			/*
			 * Check EOF (should never happen, since last 5 bytes
			 * are supposed to be literals)
			 */
			if (op == oend)
				goto _output_error;
			continue;
		}
		LZ4_SECURECOPY(ref, op, cpy);
		op = cpy; /* correction */
	}
	/* end of decoding */
	return (int) (((char *)ip) - source);

	/* write overflow error detected */
_output_error:
	return -1;
}

static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
				int isize, size_t maxoutputsize)
{
	const BYTE *ip = (const BYTE *) source;
	const BYTE *const iend = ip + isize;
	const BYTE *ref;


	BYTE *op = (BYTE *) dest;
	BYTE * const oend = op + maxoutputsize;
	BYTE *cpy;

	/* Main Loop */
	while (ip < iend) {

		unsigned token;
		size_t length;

		/* get runlength */
		token = *ip++;
		length = (token >> ML_BITS);
		if (length == RUN_MASK) {
			int s = 255;
			while ((ip < iend) && (s == 255)) {
				s = *ip++;
				if (unlikely(length > (size_t)(length + s)))
					goto _output_error;
				length += s;
			}
		}
		/* copy literals */
		cpy = op + length;
		if ((cpy > oend - COPYLENGTH) ||
			(ip + length > iend - COPYLENGTH)) {

			if (cpy > oend)
				goto _output_error;/* writes beyond buffer */

			if (ip + length != iend)
				goto _output_error;/*
						    * Error: LZ4 format requires
						    * to consume all input
						    * at this stage
						    */
			memcpy(op, ip, length);
			op += length;
			break;/* Necessarily EOF, due to parsing restrictions */
		}
		LZ4_WILDCOPY(ip, op, cpy);
		ip -= (op - cpy);
		op = cpy;

		/* get offset */
		LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
		ip += 2;
		if (ref < (BYTE * const) dest)
			goto _output_error;
			/*
			 * Error : offset creates reference
			 * outside of destination buffer
			 */

		/* get matchlength */
		length = (token & ML_MASK);
		if (length == ML_MASK) {
			while (ip < iend) {
				int s = *ip++;
				if (unlikely(length > (size_t)(length + s)))
					goto _output_error;
				length += s;
				if (s == 255)
					continue;
				break;
			}
		}

		/* copy repeated sequence */
		if (unlikely((op - ref) < STEPSIZE)) {
#if LZ4_ARCH64
			int dec64 = dec64table[op - ref];
#else
			const int dec64 = 0;
#endif
				op[0] = ref[0];
				op[1] = ref[1];
				op[2] = ref[2];
				op[3] = ref[3];
				op += 4;
				ref += 4;
				ref -= dec32table[op - ref];
				PUT4(ref, op);
				op += STEPSIZE - 4;
				ref -= dec64;
		} else {
			LZ4_COPYSTEP(ref, op);
		}
		cpy = op + length - (STEPSIZE-4);
		if (cpy > oend - COPYLENGTH) {
			if (cpy > oend)
				goto _output_error; /* write outside of buf */

			LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
			while (op < cpy)
				*op++ = *ref++;
			op = cpy;
			/*
			 * Check EOF (should never happen, since last 5 bytes
			 * are supposed to be literals)
			 */
			if (op == oend)
				goto _output_error;
			continue;
		}
		LZ4_SECURECOPY(ref, op, cpy);
		op = cpy; /* correction */
	}
	/* end of decoding */
	return (int) (((char *) op) - dest);

	/* write overflow error detected */
_output_error:
	return -1;
}

int lz4_decompress(const unsigned char *src, size_t *src_len,
		unsigned char *dest, size_t actual_dest_len)
{
	int ret = -1;
	int input_len = 0;

	input_len = lz4_uncompress(src, dest, actual_dest_len);
	if (input_len < 0)
		goto exit_0;
	*src_len = input_len;

	return 0;
exit_0:
	return ret;
}
#ifndef STATIC
EXPORT_SYMBOL(lz4_decompress);
#endif

int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
		unsigned char *dest, size_t *dest_len)
{
	int ret = -1;
	int out_len = 0;

	out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len,
					*dest_len);
	if (out_len < 0)
		goto exit_0;
	*dest_len = out_len;

	return 0;
exit_0:
	return ret;
}
#ifndef STATIC
EXPORT_SYMBOL(lz4_decompress_unknownoutputsize);

MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("LZ4 Decompressor");
#endif
Commit	Line	Data
cffb78b0 KL	1	/*
	2	* LZ4 Decompressor for Linux kernel
	3	*
e76e1fdf	4	* Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
cffb78b0 KL	5	*
	6	* Based on LZ4 implementation by Yann Collet.
	7	*
	8	* LZ4 - Fast LZ compression algorithm
	9	* Copyright (C) 2011-2012, Yann Collet.
	10	* BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
	11	*
	12	* Redistribution and use in source and binary forms, with or without
	13	* modification, are permitted provided that the following conditions are
	14	* met:
	15	*
	16	* * Redistributions of source code must retain the above copyright
	17	* notice, this list of conditions and the following disclaimer.
	18	* * Redistributions in binary form must reproduce the above
	19	* copyright notice, this list of conditions and the following disclaimer
	20	* in the documentation and/or other materials provided with the
	21	* distribution.
	22	*
	23	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	24	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	25	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	26	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	27	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	28	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	29	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	30	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	31	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	32	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	33	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	34	*
	35	* You can contact the author at :
	36	* - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
	37	* - LZ4 source repository : http://code.google.com/p/lz4/
	38	*/
	39
	40	#ifndef STATIC
	41	#include <linux/module.h>
	42	#include <linux/kernel.h>
	43	#endif
	44	#include <linux/lz4.h>
	45
	46	#include <asm/unaligned.h>
	47
	48	#include "lz4defs.h"
	49
bea2b592 RV	50	static const int dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
	51	#if LZ4_ARCH64
	52	static const int dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
	53	#endif
	54
cffb78b0 KL	55	static int lz4_uncompress(const char source, char dest, int osize)
	56	{
	57	const BYTE ip = (const BYTE ) source;
	58	const BYTE *ref;
	59	BYTE op = (BYTE ) dest;
	60	BYTE * const oend = op + osize;
	61	BYTE *cpy;
	62	unsigned token;
	63	size_t length;
cffb78b0 KL	64
	65	while (1) {
	66
	67	/* get runlength */
	68	token = *ip++;
	69	length = (token >> ML_BITS);
	70	if (length == RUN_MASK) {
	71	size_t len;
	72
	73	len = *ip++;
	74	for (; len == 255; length += 255)
	75	len = *ip++;
206204a1 GKH	76	if (unlikely(length > (size_t)(length + len)))
206204a1 GKH	77	goto _output_error;
cffb78b0 KL	78	length += len;
	79	}
	80
	81	/* copy literals */
	82	cpy = op + length;
	83	if (unlikely(cpy > oend - COPYLENGTH)) {
	84	/*
	85	* Error: not enough place for another match
	86	* (min 4) + 5 literals
	87	*/
	88	if (cpy != oend)
	89	goto _output_error;
	90
	91	memcpy(op, ip, length);
	92	ip += length;
	93	break; /* EOF */
	94	}
	95	LZ4_WILDCOPY(ip, op, cpy);
	96	ip -= (op - cpy);
	97	op = cpy;
	98
	99	/* get offset */
	100	LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
	101	ip += 2;
	102
	103	/* Error: offset create reference outside destination buffer */
	104	if (unlikely(ref < (BYTE *const) dest))
	105	goto _output_error;
	106
	107	/* get matchlength */
	108	length = token & ML_MASK;
	109	if (length == ML_MASK) {
	110	for (; *ip == 255; length += 255)
	111	ip++;
4148c1f6 GKH	112	if (unlikely(length > (size_t)(length + *ip)))
4148c1f6 GKH	113	goto _output_error;
cffb78b0 KL	114	length += *ip++;
	115	}
	116
	117	/* copy repeated sequence */
	118	if (unlikely((op - ref) < STEPSIZE)) {
	119	#if LZ4_ARCH64
bea2b592	120	int dec64 = dec64table[op - ref];
cffb78b0 KL	121	#else
	122	const int dec64 = 0;
	123	#endif
	124	op[0] = ref[0];
	125	op[1] = ref[1];
	126	op[2] = ref[2];
	127	op[3] = ref[3];
	128	op += 4;
	129	ref += 4;
	130	ref -= dec32table[op-ref];
	131	PUT4(ref, op);
	132	op += STEPSIZE - 4;
	133	ref -= dec64;
	134	} else {
	135	LZ4_COPYSTEP(ref, op);
	136	}
	137	cpy = op + length - (STEPSIZE - 4);
	138	if (cpy > (oend - COPYLENGTH)) {
	139
	140	/* Error: request to write beyond destination buffer */
	141	if (cpy > oend)
	142	goto _output_error;
d5e7cafd JY	143	if ((ref + COPYLENGTH) > oend \|\|
	144	(op + COPYLENGTH) > oend)
	145	goto _output_error;
cffb78b0 KL	146	LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
	147	while (op < cpy)
	148	op++ = ref++;
	149	op = cpy;
	150	/*
	151	* Check EOF (should never happen, since last 5 bytes
	152	* are supposed to be literals)
	153	*/
	154	if (op == oend)
	155	goto _output_error;
	156	continue;
	157	}
	158	LZ4_SECURECOPY(ref, op, cpy);
	159	op = cpy; /* correction */
	160	}
	161	/* end of decoding */
	162	return (int) (((char *)ip) - source);
	163
	164	/* write overflow error detected */
	165	_output_error:
4148c1f6	166	return -1;
cffb78b0 KL	167	}
	168
	169	static int lz4_uncompress_unknownoutputsize(const char source, char dest,
	170	int isize, size_t maxoutputsize)
	171	{
	172	const BYTE ip = (const BYTE ) source;
	173	const BYTE *const iend = ip + isize;
	174	const BYTE *ref;
	175
	176
	177	BYTE op = (BYTE ) dest;
	178	BYTE * const oend = op + maxoutputsize;
	179	BYTE *cpy;
	180
cffb78b0 KL	181	/* Main Loop */
	182	while (ip < iend) {
	183
	184	unsigned token;
	185	size_t length;
	186
	187	/* get runlength */
	188	token = *ip++;
	189	length = (token >> ML_BITS);
	190	if (length == RUN_MASK) {
	191	int s = 255;
	192	while ((ip < iend) && (s == 255)) {
	193	s = *ip++;
4a3a9904 GKH	194	if (unlikely(length > (size_t)(length + s)))
4a3a9904 GKH	195	goto _output_error;
cffb78b0 KL	196	length += s;
	197	}
	198	}
	199	/* copy literals */
	200	cpy = op + length;
	201	if ((cpy > oend - COPYLENGTH) \|\|
	202	(ip + length > iend - COPYLENGTH)) {
	203
	204	if (cpy > oend)
	205	goto _output_error;/* writes beyond buffer */
	206
	207	if (ip + length != iend)
	208	goto _output_error;/*
	209	* Error: LZ4 format requires
	210	* to consume all input
	211	* at this stage
	212	*/
	213	memcpy(op, ip, length);
	214	op += length;
	215	break;/* Necessarily EOF, due to parsing restrictions */
	216	}
	217	LZ4_WILDCOPY(ip, op, cpy);
	218	ip -= (op - cpy);
	219	op = cpy;
	220
	221	/* get offset */
	222	LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
	223	ip += 2;
	224	if (ref < (BYTE * const) dest)
	225	goto _output_error;
	226	/*
	227	* Error : offset creates reference
	228	* outside of destination buffer
	229	*/
	230
	231	/* get matchlength */
	232	length = (token & ML_MASK);
	233	if (length == ML_MASK) {
	234	while (ip < iend) {
	235	int s = *ip++;
4a3a9904 GKH	236	if (unlikely(length > (size_t)(length + s)))
4a3a9904 GKH	237	goto _output_error;
cffb78b0 KL	238	length += s;
	239	if (s == 255)
	240	continue;
	241	break;
	242	}
	243	}
	244
	245	/* copy repeated sequence */
	246	if (unlikely((op - ref) < STEPSIZE)) {
	247	#if LZ4_ARCH64
bea2b592	248	int dec64 = dec64table[op - ref];
cffb78b0 KL	249	#else
	250	const int dec64 = 0;
	251	#endif
	252	op[0] = ref[0];
	253	op[1] = ref[1];
	254	op[2] = ref[2];
	255	op[3] = ref[3];
	256	op += 4;
	257	ref += 4;
	258	ref -= dec32table[op - ref];
	259	PUT4(ref, op);
	260	op += STEPSIZE - 4;
	261	ref -= dec64;
	262	} else {
	263	LZ4_COPYSTEP(ref, op);
	264	}
	265	cpy = op + length - (STEPSIZE-4);
	266	if (cpy > oend - COPYLENGTH) {
	267	if (cpy > oend)
	268	goto _output_error; /* write outside of buf */
	269
	270	LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
	271	while (op < cpy)
	272	op++ = ref++;
	273	op = cpy;
	274	/*
	275	* Check EOF (should never happen, since last 5 bytes
	276	* are supposed to be literals)
	277	*/
	278	if (op == oend)
	279	goto _output_error;
	280	continue;
	281	}
	282	LZ4_SECURECOPY(ref, op, cpy);
	283	op = cpy; /* correction */
	284	}
	285	/* end of decoding */
	286	return (int) (((char *) op) - dest);
	287
	288	/* write overflow error detected */
	289	_output_error:
4a3a9904	290	return -1;
cffb78b0 KL	291	}
cffb78b0 KL	292
b34081f1 SS	293	int lz4_decompress(const unsigned char src, size_t src_len,
b34081f1 SS	294	unsigned char *dest, size_t actual_dest_len)
cffb78b0 KL	295	{
	296	int ret = -1;
	297	int input_len = 0;
	298
	299	input_len = lz4_uncompress(src, dest, actual_dest_len);
	300	if (input_len < 0)
	301	goto exit_0;
	302	*src_len = input_len;
	303
	304	return 0;
	305	exit_0:
	306	return ret;
	307	}
	308	#ifndef STATIC
ee8a99bd	309	EXPORT_SYMBOL(lz4_decompress);
cffb78b0 KL	310	#endif
cffb78b0 KL	311
b34081f1 SS	312	int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
b34081f1 SS	313	unsigned char dest, size_t dest_len)
cffb78b0 KL	314	{
	315	int ret = -1;
	316	int out_len = 0;
	317
	318	out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len,
	319	*dest_len);
	320	if (out_len < 0)
	321	goto exit_0;
	322	*dest_len = out_len;
	323
	324	return 0;
	325	exit_0:
	326	return ret;
	327	}
	328	#ifndef STATIC
ee8a99bd	329	EXPORT_SYMBOL(lz4_decompress_unknownoutputsize);
cffb78b0	330
ee8a99bd	331	MODULE_LICENSE("Dual BSD/GPL");
cffb78b0 KL	332	MODULE_DESCRIPTION("LZ4 Decompressor");
cffb78b0 KL	333	#endif