1 /*
2 * LZ4 - Fast LZ compression algorithm
3 * Header File
4 * Copyright (C) 2011-2013, Yann Collet.
5 * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are
9 * met:
10 *
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * * Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following disclaimer
15 * in the documentation and/or other materials provided with the
16 * distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * You can contact the author at :
31 * - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
32 * - LZ4 source repository : http://code.google.com/p/lz4/
33 */
34
35 #include "fsys_zfs.h"
36 #include <string.h>
37
38 static int LZ4_uncompress_unknownOutputSize(const char *source, char *dest,
39 int isize, int maxOutputSize);
40
41 int
lz4_decompress(void * s_start,void * d_start,size_t s_len,size_t d_len)42 lz4_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len)
43 {
44 const uint8_t *src = s_start;
45 uint32_t bufsiz = (src[0] << 24) | (src[1] << 16) | (src[2] << 8) |
46 src[3];
47
48 /* invalid compressed buffer size encoded at start */
49 if (bufsiz + 4 > s_len)
50 return (1);
51
52 /*
53 * Returns 0 on success (decompression function returned non-negative)
54 * and non-zero on failure (decompression function returned negative).
55 */
56 return (LZ4_uncompress_unknownOutputSize(s_start + 4, d_start, bufsiz,
57 d_len) < 0);
58 }
59
60 /*
61 * CPU Feature Detection
62 */
63
64 /* 32 or 64 bits ? */
65 #if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || \
66 defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || \
67 defined(__LP64__) || defined(_LP64))
68 #define LZ4_ARCH64 1
69 #else
70 #define LZ4_ARCH64 0
71 #endif
72
73 /*
74 * Little Endian or Big Endian?
75 * Note: overwrite the below #define if you know your architecture endianess.
76 */
77 #if (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || \
78 defined(_BIG_ENDIAN) || defined(_ARCH_PPC) || defined(__PPC__) || \
79 defined(__PPC) || defined(PPC) || defined(__powerpc__) || \
80 defined(__powerpc) || defined(powerpc) || \
81 ((defined(__BYTE_ORDER__)&&(__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))))
82 #define LZ4_BIG_ENDIAN 1
83 #else
84 /*
85 * Little Endian assumed. PDP Endian and other very rare endian format
86 * are unsupported.
87 */
88 #endif
89
90 /*
91 * Compiler Options
92 */
93 #if __STDC_VERSION__ >= 199901L /* C99 */
94 /* "restrict" is a known keyword */
95 #else
96 /* Disable restrict */
97 #define restrict
98 #endif
99
100 #define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
101
102 #define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) \
103 | (((x) & 0xffu) << 8)))
104
105 #if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__)
106 #define expect(expr, value) (__builtin_expect((expr), (value)))
107 #else
108 #define expect(expr, value) (expr)
109 #endif
110
111 #define likely(expr) expect((expr) != 0, 1)
112 #define unlikely(expr) expect((expr) != 0, 0)
113
114 /* Basic types */
115 #define BYTE uint8_t
116 #define U16 uint16_t
117 #define U32 uint32_t
118 #define S32 int32_t
119 #define U64 uint64_t
120
121 typedef struct _U16_S {
122 U16 v;
123 } U16_S;
124 typedef struct _U32_S {
125 U32 v;
126 } U32_S;
127 typedef struct _U64_S {
128 U64 v;
129 } U64_S;
130
131 #define A64(x) (((U64_S *)(x))->v)
132 #define A32(x) (((U32_S *)(x))->v)
133 #define A16(x) (((U16_S *)(x))->v)
134
135 /*
136 * Constants
137 */
138 #define MINMATCH 4
139
140 #define COPYLENGTH 8
141 #define LASTLITERALS 5
142
143 #define ML_BITS 4
144 #define ML_MASK ((1U<<ML_BITS)-1)
145 #define RUN_BITS (8-ML_BITS)
146 #define RUN_MASK ((1U<<RUN_BITS)-1)
147
148 /*
149 * Architecture-specific macros
150 */
151 #if LZ4_ARCH64
152 #define STEPSIZE 8
153 #define UARCH U64
154 #define AARCH A64
155 #define LZ4_COPYSTEP(s, d) A64(d) = A64(s); d += 8; s += 8;
156 #define LZ4_COPYPACKET(s, d) LZ4_COPYSTEP(s, d)
157 #define LZ4_SECURECOPY(s, d, e) if (d < e) LZ4_WILDCOPY(s, d, e)
158 #define HTYPE U32
159 #define INITBASE(base) const BYTE* const base = ip
160 #else
161 #define STEPSIZE 4
162 #define UARCH U32
163 #define AARCH A32
164 #define LZ4_COPYSTEP(s, d) A32(d) = A32(s); d += 4; s += 4;
165 #define LZ4_COPYPACKET(s, d) LZ4_COPYSTEP(s, d); LZ4_COPYSTEP(s, d);
166 #define LZ4_SECURECOPY LZ4_WILDCOPY
167 #define HTYPE const BYTE*
168 #define INITBASE(base) const int base = 0
169 #endif
170
171 #if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE))
172 #define LZ4_READ_LITTLEENDIAN_16(d, s, p) \
173 { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }
174 #define LZ4_WRITE_LITTLEENDIAN_16(p, i) \
175 { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p += 2; }
176 #else
177 #define LZ4_READ_LITTLEENDIAN_16(d, s, p) { d = (s) - A16(p); }
178 #define LZ4_WRITE_LITTLEENDIAN_16(p, v) { A16(p) = v; p += 2; }
179 #endif
180
181 /* Macros */
182 #define LZ4_WILDCOPY(s, d, e) do { LZ4_COPYPACKET(s, d) } while (d < e);
183
184 /* Decompression functions */
185
186 static int
LZ4_uncompress_unknownOutputSize(const char * source,char * dest,int isize,int maxOutputSize)187 LZ4_uncompress_unknownOutputSize(const char *source,
188 char *dest, int isize, int maxOutputSize)
189 {
190 /* Local Variables */
191 const BYTE *restrict ip = (const BYTE *) source;
192 const BYTE *const iend = ip + isize;
193 const BYTE *restrict ref;
194
195 BYTE *restrict op = (BYTE *) dest;
196 BYTE *const oend = op + maxOutputSize;
197 BYTE *cpy;
198
199 size_t dec[] = { 0, 3, 2, 3, 0, 0, 0, 0 };
200
201 /* Main Loop */
202 while (ip < iend) {
203 BYTE token;
204 int length;
205
206 /* get runlength */
207 token = *ip++;
208 if ((length = (token >> ML_BITS)) == RUN_MASK) {
209 int s = 255;
210 while ((ip < iend) && (s == 255)) {
211 s = *ip++;
212 length += s;
213 }
214 }
215 /* copy literals */
216 cpy = op + length;
217 /* CORNER-CASE: cpy might overflow. */
218 if (cpy < op)
219 goto _output_error; /* cpy was overflowed, bail! */
220 if ((cpy > oend - COPYLENGTH) ||
221 (ip + length > iend - COPYLENGTH)) {
222 if (cpy > oend)
223 /*
224 * Error: request to write beyond destination
225 * buffer.
226 */
227 goto _output_error;
228 if (ip + length > iend)
229 /*
230 * Error : request to read beyond source
231 * buffer.
232 */
233 goto _output_error;
234 memcpy(op, ip, length);
235 op += length;
236 ip += length;
237 if (ip < iend)
238 /* Error : LZ4 format violation */
239 goto _output_error;
240 /* Necessarily EOF, due to parsing restrictions. */
241 break;
242 }
243 LZ4_WILDCOPY(ip, op, cpy);
244 ip -= (op - cpy);
245 op = cpy;
246
247 /* get offset */
248 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
249 ip += 2;
250 if (ref < (BYTE * const) dest)
251 /*
252 * Error: offset creates reference outside of
253 * destination buffer.
254 */
255 goto _output_error;
256
257 /* get matchlength */
258 if ((length = (token & ML_MASK)) == ML_MASK) {
259 while (ip < iend) {
260 int s = *ip++;
261 length += s;
262 if (s == 255)
263 continue;
264 break;
265 }
266 }
267 /* copy repeated sequence */
268 if unlikely(op - ref < STEPSIZE) {
269 #if LZ4_ARCH64
270 size_t dec2table[] = { 0, 0, 0, -1, 0, 1, 2, 3 };
271 size_t dec2 = dec2table[op - ref];
272 #else
273 const int dec2 = 0;
274 #endif
275 *op++ = *ref++;
276 *op++ = *ref++;
277 *op++ = *ref++;
278 *op++ = *ref++;
279 ref -= dec[op - ref];
280 A32(op) = A32(ref);
281 op += STEPSIZE - 4;
282 ref -= dec2;
283 } else {
284 LZ4_COPYSTEP(ref, op);
285 }
286 cpy = op + length - (STEPSIZE - 4);
287 if (cpy > oend - COPYLENGTH) {
288 if (cpy > oend)
289 /*
290 * Error: request to write outside of
291 * destination buffer.
292 */
293 goto _output_error;
294 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
295 while (op < cpy)
296 *op++ = *ref++;
297 op = cpy;
298 if (op == oend)
299 /*
300 * Check EOF (should never happen, since last
301 * 5 bytes are supposed to be literals).
302 */
303 break;
304 continue;
305 }
306 LZ4_SECURECOPY(ref, op, cpy);
307 op = cpy; /* correction */
308 }
309
310 /* end of decoding */
311 return (int)(((char *)op) - dest);
312
313 /* write overflow error detected */
314 _output_error:
315 return (int)(-(((char *)ip) - source));
316 }
317