Merge tag 'v2.14.1'
[git/git.git] / diff-delta.c
CommitLineData
a310d434
NP
1/*
2 * diff-delta.c: generate a delta between two buffers
3 *
366b53c1
NP
4 * This code was greatly inspired by parts of LibXDiff from Davide Libenzi
5 * http://www.xmailserver.org/xdiff-lib.html
a310d434 6 *
03aa8ff3 7 * Rewritten for GIT by Nicolas Pitre <nico@fluxnic.net>, (C) 2005-2007
a310d434 8 *
366b53c1
NP
9 * This code is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
a310d434
NP
12 */
13
63f17569 14#include "git-compat-util.h"
85023577 15#include "delta.h"
a310d434 16
08abe669
NP
17/* maximum hash entry list for the same hash bucket */
18#define HASH_LIMIT 64
a310d434 19
3dc5a9e4
NP
20#define RABIN_SHIFT 23
21#define RABIN_WINDOW 16
22
23static const unsigned int T[256] = {
24 0x00000000, 0xab59b4d1, 0x56b369a2, 0xfdeadd73, 0x063f6795, 0xad66d344,
25 0x508c0e37, 0xfbd5bae6, 0x0c7ecf2a, 0xa7277bfb, 0x5acda688, 0xf1941259,
26 0x0a41a8bf, 0xa1181c6e, 0x5cf2c11d, 0xf7ab75cc, 0x18fd9e54, 0xb3a42a85,
27 0x4e4ef7f6, 0xe5174327, 0x1ec2f9c1, 0xb59b4d10, 0x48719063, 0xe32824b2,
28 0x1483517e, 0xbfdae5af, 0x423038dc, 0xe9698c0d, 0x12bc36eb, 0xb9e5823a,
29 0x440f5f49, 0xef56eb98, 0x31fb3ca8, 0x9aa28879, 0x6748550a, 0xcc11e1db,
30 0x37c45b3d, 0x9c9defec, 0x6177329f, 0xca2e864e, 0x3d85f382, 0x96dc4753,
31 0x6b369a20, 0xc06f2ef1, 0x3bba9417, 0x90e320c6, 0x6d09fdb5, 0xc6504964,
32 0x2906a2fc, 0x825f162d, 0x7fb5cb5e, 0xd4ec7f8f, 0x2f39c569, 0x846071b8,
33 0x798aaccb, 0xd2d3181a, 0x25786dd6, 0x8e21d907, 0x73cb0474, 0xd892b0a5,
34 0x23470a43, 0x881ebe92, 0x75f463e1, 0xdeadd730, 0x63f67950, 0xc8afcd81,
35 0x354510f2, 0x9e1ca423, 0x65c91ec5, 0xce90aa14, 0x337a7767, 0x9823c3b6,
36 0x6f88b67a, 0xc4d102ab, 0x393bdfd8, 0x92626b09, 0x69b7d1ef, 0xc2ee653e,
37 0x3f04b84d, 0x945d0c9c, 0x7b0be704, 0xd05253d5, 0x2db88ea6, 0x86e13a77,
38 0x7d348091, 0xd66d3440, 0x2b87e933, 0x80de5de2, 0x7775282e, 0xdc2c9cff,
39 0x21c6418c, 0x8a9ff55d, 0x714a4fbb, 0xda13fb6a, 0x27f92619, 0x8ca092c8,
40 0x520d45f8, 0xf954f129, 0x04be2c5a, 0xafe7988b, 0x5432226d, 0xff6b96bc,
41 0x02814bcf, 0xa9d8ff1e, 0x5e738ad2, 0xf52a3e03, 0x08c0e370, 0xa39957a1,
42 0x584ced47, 0xf3155996, 0x0eff84e5, 0xa5a63034, 0x4af0dbac, 0xe1a96f7d,
43 0x1c43b20e, 0xb71a06df, 0x4ccfbc39, 0xe79608e8, 0x1a7cd59b, 0xb125614a,
44 0x468e1486, 0xedd7a057, 0x103d7d24, 0xbb64c9f5, 0x40b17313, 0xebe8c7c2,
45 0x16021ab1, 0xbd5bae60, 0x6cb54671, 0xc7ecf2a0, 0x3a062fd3, 0x915f9b02,
46 0x6a8a21e4, 0xc1d39535, 0x3c394846, 0x9760fc97, 0x60cb895b, 0xcb923d8a,
47 0x3678e0f9, 0x9d215428, 0x66f4eece, 0xcdad5a1f, 0x3047876c, 0x9b1e33bd,
48 0x7448d825, 0xdf116cf4, 0x22fbb187, 0x89a20556, 0x7277bfb0, 0xd92e0b61,
49 0x24c4d612, 0x8f9d62c3, 0x7836170f, 0xd36fa3de, 0x2e857ead, 0x85dcca7c,
50 0x7e09709a, 0xd550c44b, 0x28ba1938, 0x83e3ade9, 0x5d4e7ad9, 0xf617ce08,
51 0x0bfd137b, 0xa0a4a7aa, 0x5b711d4c, 0xf028a99d, 0x0dc274ee, 0xa69bc03f,
52 0x5130b5f3, 0xfa690122, 0x0783dc51, 0xacda6880, 0x570fd266, 0xfc5666b7,
53 0x01bcbbc4, 0xaae50f15, 0x45b3e48d, 0xeeea505c, 0x13008d2f, 0xb85939fe,
54 0x438c8318, 0xe8d537c9, 0x153feaba, 0xbe665e6b, 0x49cd2ba7, 0xe2949f76,
55 0x1f7e4205, 0xb427f6d4, 0x4ff24c32, 0xe4abf8e3, 0x19412590, 0xb2189141,
56 0x0f433f21, 0xa41a8bf0, 0x59f05683, 0xf2a9e252, 0x097c58b4, 0xa225ec65,
57 0x5fcf3116, 0xf49685c7, 0x033df00b, 0xa86444da, 0x558e99a9, 0xfed72d78,
58 0x0502979e, 0xae5b234f, 0x53b1fe3c, 0xf8e84aed, 0x17bea175, 0xbce715a4,
59 0x410dc8d7, 0xea547c06, 0x1181c6e0, 0xbad87231, 0x4732af42, 0xec6b1b93,
60 0x1bc06e5f, 0xb099da8e, 0x4d7307fd, 0xe62ab32c, 0x1dff09ca, 0xb6a6bd1b,
61 0x4b4c6068, 0xe015d4b9, 0x3eb80389, 0x95e1b758, 0x680b6a2b, 0xc352defa,
62 0x3887641c, 0x93ded0cd, 0x6e340dbe, 0xc56db96f, 0x32c6cca3, 0x999f7872,
63 0x6475a501, 0xcf2c11d0, 0x34f9ab36, 0x9fa01fe7, 0x624ac294, 0xc9137645,
64 0x26459ddd, 0x8d1c290c, 0x70f6f47f, 0xdbaf40ae, 0x207afa48, 0x8b234e99,
65 0x76c993ea, 0xdd90273b, 0x2a3b52f7, 0x8162e626, 0x7c883b55, 0xd7d18f84,
66 0x2c043562, 0x875d81b3, 0x7ab75cc0, 0xd1eee811
67};
68
69static const unsigned int U[256] = {
70 0x00000000, 0x7eb5200d, 0x5633f4cb, 0x2886d4c6, 0x073e5d47, 0x798b7d4a,
71 0x510da98c, 0x2fb88981, 0x0e7cba8e, 0x70c99a83, 0x584f4e45, 0x26fa6e48,
72 0x0942e7c9, 0x77f7c7c4, 0x5f711302, 0x21c4330f, 0x1cf9751c, 0x624c5511,
73 0x4aca81d7, 0x347fa1da, 0x1bc7285b, 0x65720856, 0x4df4dc90, 0x3341fc9d,
74 0x1285cf92, 0x6c30ef9f, 0x44b63b59, 0x3a031b54, 0x15bb92d5, 0x6b0eb2d8,
75 0x4388661e, 0x3d3d4613, 0x39f2ea38, 0x4747ca35, 0x6fc11ef3, 0x11743efe,
76 0x3eccb77f, 0x40799772, 0x68ff43b4, 0x164a63b9, 0x378e50b6, 0x493b70bb,
77 0x61bda47d, 0x1f088470, 0x30b00df1, 0x4e052dfc, 0x6683f93a, 0x1836d937,
78 0x250b9f24, 0x5bbebf29, 0x73386bef, 0x0d8d4be2, 0x2235c263, 0x5c80e26e,
79 0x740636a8, 0x0ab316a5, 0x2b7725aa, 0x55c205a7, 0x7d44d161, 0x03f1f16c,
80 0x2c4978ed, 0x52fc58e0, 0x7a7a8c26, 0x04cfac2b, 0x73e5d470, 0x0d50f47d,
81 0x25d620bb, 0x5b6300b6, 0x74db8937, 0x0a6ea93a, 0x22e87dfc, 0x5c5d5df1,
82 0x7d996efe, 0x032c4ef3, 0x2baa9a35, 0x551fba38, 0x7aa733b9, 0x041213b4,
83 0x2c94c772, 0x5221e77f, 0x6f1ca16c, 0x11a98161, 0x392f55a7, 0x479a75aa,
84 0x6822fc2b, 0x1697dc26, 0x3e1108e0, 0x40a428ed, 0x61601be2, 0x1fd53bef,
85 0x3753ef29, 0x49e6cf24, 0x665e46a5, 0x18eb66a8, 0x306db26e, 0x4ed89263,
86 0x4a173e48, 0x34a21e45, 0x1c24ca83, 0x6291ea8e, 0x4d29630f, 0x339c4302,
87 0x1b1a97c4, 0x65afb7c9, 0x446b84c6, 0x3adea4cb, 0x1258700d, 0x6ced5000,
88 0x4355d981, 0x3de0f98c, 0x15662d4a, 0x6bd30d47, 0x56ee4b54, 0x285b6b59,
89 0x00ddbf9f, 0x7e689f92, 0x51d01613, 0x2f65361e, 0x07e3e2d8, 0x7956c2d5,
90 0x5892f1da, 0x2627d1d7, 0x0ea10511, 0x7014251c, 0x5facac9d, 0x21198c90,
91 0x099f5856, 0x772a785b, 0x4c921c31, 0x32273c3c, 0x1aa1e8fa, 0x6414c8f7,
92 0x4bac4176, 0x3519617b, 0x1d9fb5bd, 0x632a95b0, 0x42eea6bf, 0x3c5b86b2,
93 0x14dd5274, 0x6a687279, 0x45d0fbf8, 0x3b65dbf5, 0x13e30f33, 0x6d562f3e,
94 0x506b692d, 0x2ede4920, 0x06589de6, 0x78edbdeb, 0x5755346a, 0x29e01467,
95 0x0166c0a1, 0x7fd3e0ac, 0x5e17d3a3, 0x20a2f3ae, 0x08242768, 0x76910765,
96 0x59298ee4, 0x279caee9, 0x0f1a7a2f, 0x71af5a22, 0x7560f609, 0x0bd5d604,
97 0x235302c2, 0x5de622cf, 0x725eab4e, 0x0ceb8b43, 0x246d5f85, 0x5ad87f88,
98 0x7b1c4c87, 0x05a96c8a, 0x2d2fb84c, 0x539a9841, 0x7c2211c0, 0x029731cd,
99 0x2a11e50b, 0x54a4c506, 0x69998315, 0x172ca318, 0x3faa77de, 0x411f57d3,
100 0x6ea7de52, 0x1012fe5f, 0x38942a99, 0x46210a94, 0x67e5399b, 0x19501996,
101 0x31d6cd50, 0x4f63ed5d, 0x60db64dc, 0x1e6e44d1, 0x36e89017, 0x485db01a,
102 0x3f77c841, 0x41c2e84c, 0x69443c8a, 0x17f11c87, 0x38499506, 0x46fcb50b,
103 0x6e7a61cd, 0x10cf41c0, 0x310b72cf, 0x4fbe52c2, 0x67388604, 0x198da609,
104 0x36352f88, 0x48800f85, 0x6006db43, 0x1eb3fb4e, 0x238ebd5d, 0x5d3b9d50,
105 0x75bd4996, 0x0b08699b, 0x24b0e01a, 0x5a05c017, 0x728314d1, 0x0c3634dc,
106 0x2df207d3, 0x534727de, 0x7bc1f318, 0x0574d315, 0x2acc5a94, 0x54797a99,
107 0x7cffae5f, 0x024a8e52, 0x06852279, 0x78300274, 0x50b6d6b2, 0x2e03f6bf,
108 0x01bb7f3e, 0x7f0e5f33, 0x57888bf5, 0x293dabf8, 0x08f998f7, 0x764cb8fa,
109 0x5eca6c3c, 0x207f4c31, 0x0fc7c5b0, 0x7172e5bd, 0x59f4317b, 0x27411176,
110 0x1a7c5765, 0x64c97768, 0x4c4fa3ae, 0x32fa83a3, 0x1d420a22, 0x63f72a2f,
111 0x4b71fee9, 0x35c4dee4, 0x1400edeb, 0x6ab5cde6, 0x42331920, 0x3c86392d,
112 0x133eb0ac, 0x6d8b90a1, 0x450d4467, 0x3bb8646a
113};
a310d434 114
08abe669 115struct index_entry {
a310d434 116 const unsigned char *ptr;
8e1454b5 117 unsigned int val;
d2100860
DK
118};
119
120struct unpacked_index_entry {
121 struct index_entry entry;
122 struct unpacked_index_entry *next;
8e1454b5 123};
a310d434 124
08abe669 125struct delta_index {
11779e79 126 unsigned long memsize;
08abe669
NP
127 const void *src_buf;
128 unsigned long src_size;
3dc5a9e4 129 unsigned int hash_mask;
63f17569 130 struct index_entry *hash[FLEX_ARRAY];
08abe669
NP
131};
132
133struct delta_index * create_delta_index(const void *buf, unsigned long bufsize)
a310d434 134{
06a9f920 135 unsigned int i, hsize, hmask, entries, prev_val, *hash_count;
08abe669
NP
136 const unsigned char *data, *buffer = buf;
137 struct delta_index *index;
d2100860
DK
138 struct unpacked_index_entry *entry, **hash;
139 struct index_entry *packed_entry, **packed_hash;
8e1454b5 140 void *mem;
06a9f920 141 unsigned long memsize;
8e1454b5 142
08abe669
NP
143 if (!buf || !bufsize)
144 return NULL;
145
3dc5a9e4 146 /* Determine index hash size. Note that indexing skips the
82e5a82f 147 first byte to allow for optimizing the Rabin's polynomial
3dc5a9e4 148 initialization in create_delta(). */
506049c7
NP
149 entries = (bufsize - 1) / RABIN_WINDOW;
150 if (bufsize >= 0xffffffffUL) {
151 /*
152 * Current delta format can't encode offsets into
153 * reference buffer with more than 32 bits.
154 */
155 entries = 0xfffffffeU / RABIN_WINDOW;
156 }
8e1454b5 157 hsize = entries / 4;
f7466e94 158 for (i = 4; (1u << i) < hsize; i++);
8e1454b5 159 hsize = 1 << i;
3dc5a9e4 160 hmask = hsize - 1;
8e1454b5
NP
161
162 /* allocate lookup index */
d2100860 163 memsize = sizeof(*hash) * hsize +
06a9f920
NP
164 sizeof(*entry) * entries;
165 mem = malloc(memsize);
8e1454b5
NP
166 if (!mem)
167 return NULL;
168 hash = mem;
08abe669
NP
169 mem = hash + hsize;
170 entry = mem;
171
8e1454b5
NP
172 memset(hash, 0, hsize * sizeof(*hash));
173
c13c6bf7
NP
174 /* allocate an array to count hash entries */
175 hash_count = calloc(hsize, sizeof(*hash_count));
176 if (!hash_count) {
d2100860 177 free(hash);
c13c6bf7
NP
178 return NULL;
179 }
180
181 /* then populate the index */
06a9f920
NP
182 prev_val = ~0;
183 for (data = buffer + entries * RABIN_WINDOW - RABIN_WINDOW;
184 data >= buffer;
185 data -= RABIN_WINDOW) {
3dc5a9e4
NP
186 unsigned int val = 0;
187 for (i = 1; i <= RABIN_WINDOW; i++)
188 val = ((val << 8) | data[i]) ^ T[val >> RABIN_SHIFT];
06a9f920
NP
189 if (val == prev_val) {
190 /* keep the lowest of consecutive identical blocks */
d2100860
DK
191 entry[-1].entry.ptr = data + RABIN_WINDOW;
192 --entries;
06a9f920
NP
193 } else {
194 prev_val = val;
195 i = val & hmask;
d2100860
DK
196 entry->entry.ptr = data + RABIN_WINDOW;
197 entry->entry.val = val;
06a9f920
NP
198 entry->next = hash[i];
199 hash[i] = entry++;
200 hash_count[i]++;
06a9f920 201 }
3dc5a9e4 202 }
a310d434 203
c13c6bf7
NP
204 /*
205 * Determine a limit on the number of entries in the same hash
82e5a82f 206 * bucket. This guards us against pathological data sets causing
c13c6bf7
NP
207 * really bad hash distribution with most entries in the same hash
208 * bucket that would bring us to O(m*n) computing costs (m and n
209 * corresponding to reference and target buffer sizes).
210 *
08abe669 211 * Make sure none of the hash buckets has more entries than
c13c6bf7
NP
212 * we're willing to test. Otherwise we cull the entry list
213 * uniformly to still preserve a good repartition across
214 * the reference buffer.
215 */
216 for (i = 0; i < hsize; i++) {
02e665ce
DK
217 int acc;
218
219 if (hash_count[i] <= HASH_LIMIT)
c13c6bf7 220 continue;
02e665ce 221
02e665ce 222 /* We leave exactly HASH_LIMIT entries in the bucket */
ce85b053 223 entries -= hash_count[i] - HASH_LIMIT;
02e665ce 224
c13c6bf7 225 entry = hash[i];
02e665ce 226 acc = 0;
ce85b053
NP
227
228 /*
229 * Assume that this loop is gone through exactly
230 * HASH_LIMIT times and is entered and left with
231 * acc==0. So the first statement in the loop
232 * contributes (hash_count[i]-HASH_LIMIT)*HASH_LIMIT
233 * to the accumulator, and the inner loop consequently
234 * is run (hash_count[i]-HASH_LIMIT) times, removing
235 * one element from the list each time. Since acc
236 * balances out to 0 at the final run, the inner loop
237 * body can't be left with entry==NULL. So we indeed
238 * encounter entry==NULL in the outer loop only.
239 */
c13c6bf7 240 do {
02e665ce
DK
241 acc += hash_count[i] - HASH_LIMIT;
242 if (acc > 0) {
243 struct unpacked_index_entry *keep = entry;
244 do {
245 entry = entry->next;
246 acc -= HASH_LIMIT;
247 } while (acc > 0);
248 keep->next = entry->next;
249 }
250 entry = entry->next;
251 } while (entry);
c13c6bf7
NP
252 }
253 free(hash_count);
254
ce85b053
NP
255 /*
256 * Now create the packed index in array form
257 * rather than linked lists.
258 */
d2100860
DK
259 memsize = sizeof(*index)
260 + sizeof(*packed_hash) * (hsize+1)
261 + sizeof(*packed_entry) * entries;
d2100860 262 mem = malloc(memsize);
d2100860
DK
263 if (!mem) {
264 free(hash);
265 return NULL;
266 }
267
268 index = mem;
269 index->memsize = memsize;
270 index->src_buf = buf;
271 index->src_size = bufsize;
272 index->hash_mask = hmask;
273
f9c5a80c 274 mem = index->hash;
d2100860
DK
275 packed_hash = mem;
276 mem = packed_hash + (hsize+1);
277 packed_entry = mem;
278
d2100860 279 for (i = 0; i < hsize; i++) {
ce85b053
NP
280 /*
281 * Coalesce all entries belonging to one linked list
282 * into consecutive array entries.
283 */
d2100860
DK
284 packed_hash[i] = packed_entry;
285 for (entry = hash[i]; entry; entry = entry->next)
286 *packed_entry++ = entry->entry;
287 }
288
ce85b053 289 /* Sentinel value to indicate the length of the last hash bucket */
d2100860 290 packed_hash[hsize] = packed_entry;
ce85b053 291
d2100860
DK
292 assert(packed_entry - (struct index_entry *)mem == entries);
293 free(hash);
294
08abe669
NP
295 return index;
296}
297
298void free_delta_index(struct delta_index *index)
299{
300 free(index);
a310d434
NP
301}
302
11779e79
BD
303unsigned long sizeof_delta_index(struct delta_index *index)
304{
305 if (index)
306 return index->memsize;
307 else
308 return 0;
309}
310
3dc5a9e4
NP
311/*
312 * The maximum size for any opcode sequence, including the initial header
82e5a82f 313 * plus Rabin window plus biggest copy.
3dc5a9e4
NP
314 */
315#define MAX_OP_SIZE (5 + 5 + 1 + RABIN_WINDOW + 7)
fe474b58 316
08abe669
NP
317void *
318create_delta(const struct delta_index *index,
319 const void *trg_buf, unsigned long trg_size,
320 unsigned long *delta_size, unsigned long max_size)
a310d434 321{
84336696 322 unsigned int i, outpos, outsize, moff, msize, val;
5a1fb2ca 323 int inscnt;
8e1454b5
NP
324 const unsigned char *ref_data, *ref_top, *data, *top;
325 unsigned char *out;
a310d434 326
08abe669 327 if (!trg_buf || !trg_size)
8e1454b5
NP
328 return NULL;
329
a310d434
NP
330 outpos = 0;
331 outsize = 8192;
fe474b58
NP
332 if (max_size && outsize >= max_size)
333 outsize = max_size + MAX_OP_SIZE + 1;
a310d434 334 out = malloc(outsize);
08abe669 335 if (!out)
a310d434 336 return NULL;
a310d434
NP
337
338 /* store reference buffer size */
08abe669
NP
339 i = index->src_size;
340 while (i >= 0x80) {
341 out[outpos++] = i | 0x80;
342 i >>= 7;
69a2d426 343 }
08abe669 344 out[outpos++] = i;
a310d434
NP
345
346 /* store target buffer size */
08abe669
NP
347 i = trg_size;
348 while (i >= 0x80) {
349 out[outpos++] = i | 0x80;
350 i >>= 7;
69a2d426 351 }
08abe669 352 out[outpos++] = i;
a310d434 353
08abe669
NP
354 ref_data = index->src_buf;
355 ref_top = ref_data + index->src_size;
356 data = trg_buf;
1d7f171c 357 top = (const unsigned char *) trg_buf + trg_size;
3dc5a9e4
NP
358
359 outpos++;
360 val = 0;
361 for (i = 0; i < RABIN_WINDOW && data < top; i++, data++) {
362 out[outpos++] = *data;
363 val = ((val << 8) | *data) ^ T[val >> RABIN_SHIFT];
364 }
365 inscnt = i;
a310d434 366
84336696
NP
367 moff = 0;
368 msize = 0;
8e1454b5 369 while (data < top) {
84336696
NP
370 if (msize < 4096) {
371 struct index_entry *entry;
372 val ^= U[data[-RABIN_WINDOW]];
373 val = ((val << 8) | *data) ^ T[val >> RABIN_SHIFT];
374 i = val & index->hash_mask;
d2100860 375 for (entry = index->hash[i]; entry < index->hash[i+1]; entry++) {
84336696
NP
376 const unsigned char *ref = entry->ptr;
377 const unsigned char *src = data;
378 unsigned int ref_size = ref_top - ref;
379 if (entry->val != val)
380 continue;
381 if (ref_size > top - src)
382 ref_size = top - src;
383 if (ref_size <= msize)
384 break;
385 while (ref_size-- && *src++ == *ref)
386 ref++;
387 if (msize < ref - entry->ptr) {
388 /* this is our best match so far */
389 msize = ref - entry->ptr;
390 moff = entry->ptr - ref_data;
391 if (msize >= 4096) /* good enough */
392 break;
393 }
a310d434
NP
394 }
395 }
396
3dc5a9e4 397 if (msize < 4) {
a310d434
NP
398 if (!inscnt)
399 outpos++;
400 out[outpos++] = *data++;
401 inscnt++;
402 if (inscnt == 0x7f) {
403 out[outpos - inscnt - 1] = inscnt;
404 inscnt = 0;
405 }
84336696 406 msize = 0;
a310d434 407 } else {
84336696 408 unsigned int left;
8e1454b5
NP
409 unsigned char *op;
410
a310d434 411 if (inscnt) {
5a1fb2ca 412 while (moff && ref_data[moff-1] == data[-1]) {
5a1fb2ca
NP
413 /* we can match one byte back */
414 msize++;
415 moff--;
416 data--;
417 outpos--;
418 if (--inscnt)
419 continue;
420 outpos--; /* remove count slot */
421 inscnt--; /* make it -1 */
422 break;
423 }
a310d434
NP
424 out[outpos - inscnt - 1] = inscnt;
425 inscnt = 0;
426 }
427
84336696
NP
428 /* A copy op is currently limited to 64KB (pack v2) */
429 left = (msize < 0x10000) ? 0 : (msize - 0x10000);
430 msize -= left;
431
8e1454b5 432 op = out + outpos++;
a310d434
NP
433 i = 0x80;
434
84336696
NP
435 if (moff & 0x000000ff)
436 out[outpos++] = moff >> 0, i |= 0x01;
437 if (moff & 0x0000ff00)
438 out[outpos++] = moff >> 8, i |= 0x02;
439 if (moff & 0x00ff0000)
440 out[outpos++] = moff >> 16, i |= 0x04;
441 if (moff & 0xff000000)
442 out[outpos++] = moff >> 24, i |= 0x08;
a310d434 443
84336696
NP
444 if (msize & 0x00ff)
445 out[outpos++] = msize >> 0, i |= 0x10;
446 if (msize & 0xff00)
447 out[outpos++] = msize >> 8, i |= 0x20;
a310d434 448
8e1454b5 449 *op = i;
84336696
NP
450
451 data += msize;
452 moff += msize;
453 msize = left;
454
455 if (msize < 4096) {
456 int j;
457 val = 0;
458 for (j = -RABIN_WINDOW; j < 0; j++)
459 val = ((val << 8) | data[j])
460 ^ T[val >> RABIN_SHIFT];
461 }
a310d434
NP
462 }
463
fe474b58 464 if (outpos >= outsize - MAX_OP_SIZE) {
a310d434
NP
465 void *tmp = out;
466 outsize = outsize * 3 / 2;
fe474b58
NP
467 if (max_size && outsize >= max_size)
468 outsize = max_size + MAX_OP_SIZE + 1;
469 if (max_size && outpos > max_size)
3dc5a9e4 470 break;
b75c6c6d 471 out = realloc(out, outsize);
a310d434
NP
472 if (!out) {
473 free(tmp);
a310d434
NP
474 return NULL;
475 }
476 }
477 }
478
479 if (inscnt)
480 out[outpos - inscnt - 1] = inscnt;
481
3dc5a9e4
NP
482 if (max_size && outpos > max_size) {
483 free(out);
484 return NULL;
485 }
486
a310d434
NP
487 *delta_size = outpos;
488 return out;
489}