1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
|
/*
LZ4 - Fast LZ compression algorithm
Copyright (C) 2011, Yann Collet.
BSD License
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.
*/
//**************************************
// Includes
//**************************************
#include <stdlib.h> // for malloc
#include <string.h> // for memset
#include "lz4.h"
//**************************************
// Performance parameter
//**************************************
// Increasing this value improves compression ratio
// Lowering this value reduces memory usage
// Lowering may also improve speed, typically on reaching cache size limits (L1 32KB for Intel, 64KB for AMD)
// Memory usage formula for 32 bits systems : N->2^(N+2) Bytes (examples : 17 -> 512KB ; 12 -> 16KB)
#define HASH_LOG 12
//**************************************
// Basic Types
//**************************************
#if defined(_MSC_VER)
#define BYTE unsigned __int8
#define U16 unsigned __int16
#define U32 unsigned __int32
#define S32 __int32
#else
#include <stdint.h>
#define BYTE uint8_t
#define U16 uint16_t
#define U32 uint32_t
#define S32 int32_t
#endif
//**************************************
// Constants
//**************************************
#define MINMATCH 4
#define SKIPSTRENGTH 6
#define STACKLIMIT 13
#define HEAPMODE (HASH_LOG>STACKLIMIT) // Defines if memory is allocated into the stack (local variable), or into the heap (malloc()).
#define COPYTOKEN 4
#define COPYLENGTH 8
#define LASTLITERALS 5
#define MFLIMIT (COPYLENGTH+MINMATCH)
#define MINLENGTH (MFLIMIT+1)
#define MAXD_LOG 16
#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
#define HASHTABLESIZE (1 << HASH_LOG)
#define HASH_MASK (HASHTABLESIZE - 1)
#define ML_BITS 4
#define ML_MASK ((1U<<ML_BITS)-1)
#define RUN_BITS (8-ML_BITS)
#define RUN_MASK ((1U<<RUN_BITS)-1)
//**************************************
// Local structures
//**************************************
struct refTables
{
const BYTE* hashTable[HASHTABLESIZE];
};
#ifdef __GNUC__
# define _PACKED __attribute__ ((packed))
#else
# define _PACKED
#endif
typedef struct _U32_S
{
U32 v;
} _PACKED U32_S;
typedef struct _U16_S
{
U16 v;
} _PACKED U16_S;
#define A32(x) (((U32_S *)(x))->v)
#define A16(x) (((U16_S *)(x))->v)
//**************************************
// Macros
//**************************************
#define LZ4_HASH_FUNCTION(i) (((i) * 2654435761U) >> ((MINMATCH*8)-HASH_LOG))
#define LZ4_HASH_VALUE(p) LZ4_HASH_FUNCTION(A32(p))
#define LZ4_COPYPACKET(s,d) A32(d) = A32(s); d+=4; s+=4; A32(d) = A32(s); d+=4; s+=4;
#define LZ4_WILDCOPY(s,d,e) do { LZ4_COPYPACKET(s,d) } while (d<e);
#define LZ4_BLINDCOPY(s,d,l) { BYTE* e=d+l; LZ4_WILDCOPY(s,d,e); d=e; }
//****************************
// Compression CODE
//****************************
int LZ4_compressCtx(void** ctx,
char* source,
char* dest,
int isize)
{
#if HEAPMODE
struct refTables *srt = (struct refTables *) (*ctx);
const BYTE** HashTable;
#else
const BYTE* HashTable[HASHTABLESIZE] = {0};
#endif
const BYTE* ip = (BYTE*) source;
const BYTE* anchor = ip;
const BYTE* const iend = ip + isize;
const BYTE* const mflimit = iend - MFLIMIT;
#define matchlimit (iend - LASTLITERALS)
BYTE* op = (BYTE*) dest;
int len, length;
const int skipStrength = SKIPSTRENGTH;
U32 forwardH;
// Init
if (isize<MINLENGTH) goto _last_literals;
#if HEAPMODE
if (*ctx == NULL)
{
srt = (struct refTables *) malloc ( sizeof(struct refTables) );
*ctx = (void*) srt;
}
HashTable = srt->hashTable;
memset((void*)HashTable, 0, sizeof(srt->hashTable));
#else
(void) ctx;
#endif
// First Byte
HashTable[LZ4_HASH_VALUE(ip)] = ip;
ip++; forwardH = LZ4_HASH_VALUE(ip);
// Main Loop
for ( ; ; )
{
int findMatchAttempts = (1U << skipStrength) + 3;
const BYTE* forwardIp = ip;
const BYTE* ref;
BYTE* token;
// Find a match
do {
U32 h = forwardH;
int step = findMatchAttempts++ >> skipStrength;
ip = forwardIp;
forwardIp = ip + step;
if (forwardIp > mflimit) { goto _last_literals; }
forwardH = LZ4_HASH_VALUE(forwardIp);
ref = HashTable[h];
HashTable[h] = ip;
} while ((ref < ip - MAX_DISTANCE) || (A32(ref) != A32(ip)));
// Catch up
while ((ip>anchor) && (ref>(BYTE*)source) && (ip[-1]==ref[-1])) { ip--; ref--; }
// Encode Literal length
length = ip - anchor;
token = op++;
if (length>=(int)RUN_MASK) { *token=(RUN_MASK<<ML_BITS); len = length-RUN_MASK; for(; len > 254 ; len-=255) *op++ = 255; *op++ = (BYTE)len; }
else *token = (length<<ML_BITS);
// Copy Literals
LZ4_BLINDCOPY(anchor, op, length);
_next_match:
// Encode Offset
A16(op) = (ip-ref); op+=2;
// Start Counting
ip+=MINMATCH; ref+=MINMATCH; // MinMatch verified
anchor = ip;
while (ip<matchlimit-3)
{
if (A32(ref) == A32(ip)) { ip+=4; ref+=4; continue; }
if (A16(ref) == A16(ip)) { ip+=2; ref+=2; }
if (*ref == *ip) ip++;
goto _endCount;
}
if ((ip<(matchlimit-1)) && (A16(ref) == A16(ip))) { ip+=2; ref+=2; }
if ((ip<matchlimit) && (*ref == *ip)) ip++;
_endCount:
len = (ip - anchor);
// Encode MatchLength
if (len>=(int)ML_MASK) { *token+=ML_MASK; len-=ML_MASK; for(; len > 509 ; len-=510) { *op++ = 255; *op++ = 255; } if (len > 254) { len-=255; *op++ = 255; } *op++ = (BYTE)len; }
else *token += len;
// Test end of chunk
if (ip > mflimit) { anchor = ip; break; }
// Test next position
ref = HashTable[LZ4_HASH_VALUE(ip)];
HashTable[LZ4_HASH_VALUE(ip)] = ip;
if ((ref > ip - (MAX_DISTANCE + 1)) && (A32(ref) == A32(ip))) { token = op++; *token=0; goto _next_match; }
// Prepare next loop
anchor = ip++;
forwardH = LZ4_HASH_VALUE(ip);
}
_last_literals:
// Encode Last Literals
{
int lastRun = iend - anchor;
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++ = (lastRun<<ML_BITS);
memcpy(op, anchor, iend - anchor);
op += iend-anchor;
}
// End
return (int) (((char*)op)-dest);
}
int LZ4_compress(char* source,
char* dest,
int isize)
{
#if HEAPMODE
void* ctx = malloc(sizeof(struct refTables));
int result = LZ4_compressCtx(&ctx, source, dest, isize);
free(ctx);
return result;
#else
return LZ4_compressCtx(NULL, source, dest, isize);
#endif
}
//****************************
// Decompression CODE
//****************************
// Note : The decoding functions LZ4_uncompress() and LZ4_uncompress_unknownOutputSize()
// are safe against "buffer overflow" attack type
// since they will *never* write outside of the provided output buffer :
// they both check this condition *before* writing anything.
// A corrupted packet however can make them *read* within the first 64K before the output buffer.
int LZ4_uncompress(char* source,
char* dest,
int osize)
{
// Local Variables
const BYTE* ip = (const BYTE*) source;
BYTE* ref;
BYTE* op = (BYTE*) dest;
BYTE* const oend = op + osize;
BYTE* cpy;
BYTE token;
U32 dec[4]={0, 3, 2, 3};
int len, length;
// Main Loop
while (1)
{
// get runlength
token = *ip++;
if ((length=(token>>ML_BITS)) == RUN_MASK) { for (;(len=*ip++)==255;length+=255){} length += len; }
// copy literals
ref = op+length;
if (ref>oend-COPYLENGTH)
{
if (ref > oend) goto _output_error;
memcpy(op, ip, length);
ip += length;
break; // Necessarily EOF
}
LZ4_WILDCOPY(ip, op, ref); ip -= (op-ref); op = ref;
// get offset
ref -= A16(ip); ip+=2;
// get matchlength
if ((length=(token&ML_MASK)) == ML_MASK) { for (;*ip==255;length+=255) {ip++;} length += *ip++; }
// copy repeated sequence
if (op-ref<COPYTOKEN)
{
*op++ = *ref++;
*op++ = *ref++;
*op++ = *ref++;
*op++ = *ref++;
ref -= dec[op-ref];
A32(op)=A32(ref);
} else { A32(op)=A32(ref); op+=4; ref+=4; }
cpy = op + length;
if (cpy > oend-COPYLENGTH)
{
if (cpy > oend) goto _output_error;
LZ4_WILDCOPY(ref, op, (oend-COPYLENGTH));
while(op<cpy) *op++=*ref++;
op=cpy;
if (op == oend) break; // Check EOF (should never happen, since last 5 bytes are supposed to be literals)
continue;
}
LZ4_WILDCOPY(ref, op, cpy);
op=cpy; // correction
}
// end of decoding
return (int) (((char*)ip)-source);
// write overflow error detected
_output_error:
return (int) (-(((char*)ip)-source));
}
int LZ4_uncompress_unknownOutputSize(
char* source,
char* dest,
int isize,
int maxOutputSize)
{
// Local Variables
const BYTE* ip = (const BYTE*) source;
const BYTE* const iend = ip + isize;
BYTE* ref;
BYTE* op = (BYTE*) dest;
BYTE* const oend = op + maxOutputSize;
BYTE* cpy;
BYTE token;
U32 dec[4]={0, 3, 2, 3};
int len, length;
// Main Loop
while (ip<iend)
{
// get runlength
token = *ip++;
if ((length=(token>>ML_BITS)) == RUN_MASK) { for (;(len=*ip++)==255;length+=255){} length += len; }
// copy literals
ref = op+length;
if (ref>oend-COPYLENGTH)
{
if (ref > oend) goto _output_error;
memcpy(op, ip, length);
ip += length;
break; // Necessarily EOF
}
LZ4_WILDCOPY(ip, op, ref); ip -= (op-ref); op = ref;
if (ip>=iend) break; // check EOF
// get offset
ref -= A16(ip); ip+=2;
// get matchlength
if ((length=(token&ML_MASK)) == ML_MASK) { for (;(len=*ip++)==255;length+=255){} length += len; }
// copy repeated sequence
if (op-ref<COPYTOKEN)
{
*op++ = *ref++;
*op++ = *ref++;
*op++ = *ref++;
*op++ = *ref++;
ref -= dec[op-ref];
A32(op)=A32(ref);
} else { A32(op)=A32(ref); op+=4; ref+=4; }
cpy = op + length;
if (cpy>oend-COPYLENGTH)
{
if (cpy > oend) goto _output_error;
LZ4_WILDCOPY(ref, op, (oend-COPYLENGTH));
while(op<cpy) *op++=*ref++;
op=cpy;
if (op == oend) break; // Check EOF (should never happen, since last 5 bytes are supposed to be literals)
continue;
}
LZ4_WILDCOPY(ref, op, cpy);
op=cpy; // correction
}
// end of decoding
return (int) (((char*)op)-dest);
// write overflow error detected
_output_error:
return (int) (-(((char*)ip)-source));
}
|