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 * $FreeBSD$
35 */
36 int lz4_decompress(void *, void *, size_t, size_t, int);
37
38 static int LZ4_uncompress_unknownOutputSize(const char *source, char *dest,
39 int isize, int maxOutputSize);
40
41 /* ARGSUSED */
42 int
lz4_decompress(void * s_start,void * d_start,size_t s_len,size_t d_len,int dummy __unused)43 lz4_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len, int dummy __unused)
44 {
45 const uint8_t *src = s_start;
46 uint32_t bufsiz = htonl(*(uint32_t *)src);
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((const char *)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 BYTE_ORDER == BIG_ENDIAN
78 #define LZ4_BIG_ENDIAN 1
79 #else
80 /*
81 * Little Endian assumed. PDP Endian and other very rare endian format
82 * are unsupported.
83 */
84 #endif
85
86 /*
87 * Unaligned memory access is automatically enabled for "common" CPU,
88 * such as x86. For others CPU, the compiler will be more cautious, and
89 * insert extra code to ensure aligned access is respected. If you know
90 * your target CPU supports unaligned memory access, you may want to
91 * force this option manually to improve performance
92 */
93 #if defined(__ARM_FEATURE_UNALIGNED)
94 #define LZ4_FORCE_UNALIGNED_ACCESS 1
95 #endif
96
97 /*
98 * Compiler Options
99 */
100 #if __STDC_VERSION__ >= 199901L /* C99 */
101 /* "restrict" is a known keyword */
102 #else
103 /* Disable restrict */
104 #define restrict
105 #endif
106
107 #define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
108
109 #define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) \
110 | (((x) & 0xffu) << 8)))
111
112 #if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__)
113 #define expect(expr, value) (__builtin_expect((expr), (value)))
114 #else
115 #define expect(expr, value) (expr)
116 #endif
117
118 #define likely(expr) expect((expr) != 0, 1)
119 #define unlikely(expr) expect((expr) != 0, 0)
120
121 /* Basic types */
122 #define BYTE uint8_t
123 #define U16 uint16_t
124 #define U32 uint32_t
125 #define S32 int32_t
126 #define U64 uint64_t
127
128 #ifndef LZ4_FORCE_UNALIGNED_ACCESS
129 #pragma pack(1)
130 #endif
131
132 typedef struct _U16_S {
133 U16 v;
134 } U16_S;
135 typedef struct _U32_S {
136 U32 v;
137 } U32_S;
138 typedef struct _U64_S {
139 U64 v;
140 } U64_S;
141
142 #ifndef LZ4_FORCE_UNALIGNED_ACCESS
143 #pragma pack()
144 #endif
145
146 #define A64(x) (((U64_S *)(x))->v)
147 #define A32(x) (((U32_S *)(x))->v)
148 #define A16(x) (((U16_S *)(x))->v)
149
150 /*
151 * Constants
152 */
153 #define MINMATCH 4
154
155 #define COPYLENGTH 8
156 #define LASTLITERALS 5
157
158 #define ML_BITS 4
159 #define ML_MASK ((1U<<ML_BITS)-1)
160 #define RUN_BITS (8-ML_BITS)
161 #define RUN_MASK ((1U<<RUN_BITS)-1)
162
163 /*
164 * Architecture-specific macros
165 */
166 #if LZ4_ARCH64
167 #define STEPSIZE 8
168 #define UARCH U64
169 #define AARCH A64
170 #define LZ4_COPYSTEP(s, d) A64(d) = A64(s); d += 8; s += 8;
171 #define LZ4_COPYPACKET(s, d) LZ4_COPYSTEP(s, d)
172 #define LZ4_SECURECOPY(s, d, e) if (d < e) LZ4_WILDCOPY(s, d, e)
173 #define HTYPE U32
174 #define INITBASE(base) const BYTE* const base = ip
175 #else
176 #define STEPSIZE 4
177 #define UARCH U32
178 #define AARCH A32
179 #define LZ4_COPYSTEP(s, d) A32(d) = A32(s); d += 4; s += 4;
180 #define LZ4_COPYPACKET(s, d) LZ4_COPYSTEP(s, d); LZ4_COPYSTEP(s, d);
181 #define LZ4_SECURECOPY LZ4_WILDCOPY
182 #define HTYPE const BYTE*
183 #define INITBASE(base) const int base = 0
184 #endif
185
186 #if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE))
187 #define LZ4_READ_LITTLEENDIAN_16(d, s, p) \
188 { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }
189 #define LZ4_WRITE_LITTLEENDIAN_16(p, i) \
190 { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p += 2; }
191 #else
192 #define LZ4_READ_LITTLEENDIAN_16(d, s, p) { d = (s) - A16(p); }
193 #define LZ4_WRITE_LITTLEENDIAN_16(p, v) { A16(p) = v; p += 2; }
194 #endif
195
196 /* Macros */
197 #define LZ4_WILDCOPY(s, d, e) do { LZ4_COPYPACKET(s, d) } while (d < e);
198
199 /* Decompression functions */
200
201 static int
LZ4_uncompress_unknownOutputSize(const char * source,char * dest,int isize,int maxOutputSize)202 LZ4_uncompress_unknownOutputSize(const char *source,
203 char *dest, int isize, int maxOutputSize)
204 {
205 /* Local Variables */
206 const BYTE *restrict ip = (const BYTE *) source;
207 const BYTE *const iend = ip + isize;
208 const BYTE *restrict ref;
209
210 BYTE *restrict op = (BYTE *) dest;
211 BYTE *const oend = op + maxOutputSize;
212 BYTE *cpy;
213
214 size_t dec[] = { 0, 3, 2, 3, 0, 0, 0, 0 };
215
216 /* Main Loop */
217 while (ip < iend) {
218 BYTE token;
219 int length;
220
221 /* get runlength */
222 token = *ip++;
223 if ((length = (token >> ML_BITS)) == RUN_MASK) {
224 int s = 255;
225 while ((ip < iend) && (s == 255)) {
226 s = *ip++;
227 length += s;
228 }
229 }
230 /* copy literals */
231 cpy = op + length;
232 if ((cpy > oend - COPYLENGTH) ||
233 (ip + length > iend - COPYLENGTH)) {
234 if (cpy > oend)
235 /*
236 * Error: request to write beyond destination
237 * buffer.
238 */
239 goto _output_error;
240 if (ip + length > iend)
241 /*
242 * Error : request to read beyond source
243 * buffer.
244 */
245 goto _output_error;
246 memcpy(op, ip, length);
247 op += length;
248 ip += length;
249 if (ip < iend)
250 /* Error : LZ4 format violation */
251 goto _output_error;
252 /* Necessarily EOF, due to parsing restrictions. */
253 break;
254 }
255 LZ4_WILDCOPY(ip, op, cpy);
256 ip -= (op - cpy);
257 op = cpy;
258
259 /* get offset */
260 LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
261 ip += 2;
262 if (ref < (BYTE * const) dest)
263 /*
264 * Error: offset creates reference outside of
265 * destination buffer.
266 */
267 goto _output_error;
268
269 /* get matchlength */
270 if ((length = (token & ML_MASK)) == ML_MASK) {
271 while (ip < iend) {
272 int s = *ip++;
273 length += s;
274 if (s == 255)
275 continue;
276 break;
277 }
278 }
279 /* copy repeated sequence */
280 if unlikely(op - ref < STEPSIZE) {
281 #if LZ4_ARCH64
282 size_t dec2table[] = { 0, 0, 0, -1, 0, 1, 2, 3 };
283 size_t dec2 = dec2table[op - ref];
284 #else
285 const int dec2 = 0;
286 #endif
287 *op++ = *ref++;
288 *op++ = *ref++;
289 *op++ = *ref++;
290 *op++ = *ref++;
291 ref -= dec[op - ref];
292 A32(op) = A32(ref);
293 op += STEPSIZE - 4;
294 ref -= dec2;
295 } else {
296 LZ4_COPYSTEP(ref, op);
297 }
298 cpy = op + length - (STEPSIZE - 4);
299 if (cpy > oend - COPYLENGTH) {
300 if (cpy > oend)
301 /*
302 * Error: request to write outside of
303 * destination buffer.
304 */
305 goto _output_error;
306 LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
307 while (op < cpy)
308 *op++ = *ref++;
309 op = cpy;
310 if (op == oend)
311 /*
312 * Check EOF (should never happen, since last
313 * 5 bytes are supposed to be literals).
314 */
315 break;
316 continue;
317 }
318 LZ4_SECURECOPY(ref, op, cpy);
319 op = cpy; /* correction */
320 }
321
322 /* end of decoding */
323 return (int)(((char *)op) - dest);
324
325 /* write overflow error detected */
326 _output_error:
327 return (int)(-(((char *)ip) - source));
328 }
329