2 * Copyright (c) 2020 Ori Bernstein
3 * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 #include <sys/types.h>
19 #include <sys/queue.h>
30 #include "got_error.h"
32 #include "got_lib_deltify.h"
33 #include "murmurhash2.h"
36 #define MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
40 * The algorihm used here is FastCDC (Fast Content-Defined Chunking)
41 * https://www.usenix.org/conference/atc16/technical-sessions/presentation/xia
44 static const uint32_t geartab[256] = {
45 0x67ed26b7, 0x32da500c, 0x53d0fee0, 0xce387dc7, 0xcd406d90, 0x2e83a4d4,
46 0x9fc9a38d, 0xb67259dc, 0xca6b1722, 0x6d2ea08c, 0x235cea2e, 0x3149bb5f,
47 0x1beda787, 0x2a6b77d5, 0x2f22d9ac, 0x91fc0544, 0xe413acfa, 0x5a30ff7a,
48 0xad6fdde0, 0x444fd0f5, 0x7ad87864, 0x58c5ff05, 0x8d2ec336, 0x2371f853,
49 0x550f8572, 0x6aa448dd, 0x7c9ddbcf, 0x95221e14, 0x2a82ec33, 0xcbec5a78,
50 0xc6795a0d, 0x243995b7, 0x1c909a2f, 0x4fded51c, 0x635d334b, 0x0e2b9999,
51 0x2702968d, 0x856de1d5, 0x3325d60e, 0xeb6a7502, 0xec2a9844, 0x0905835a,
52 0xa1820375, 0xa4be5cab, 0x96a6c058, 0x2c2ccd70, 0xba40fce3, 0xd794c46b,
53 0x8fbae83e, 0xc3aa7899, 0x3d3ff8ed, 0xa0d42b5b, 0x571c0c97, 0xd2811516,
54 0xf7e7b96c, 0x4fd2fcbd, 0xe2fdec94, 0x282cc436, 0x78e8e95c, 0x80a3b613,
55 0xcfbee20c, 0xd4a32d1c, 0x2a12ff13, 0x6af82936, 0xe5630258, 0x8efa6a98,
56 0x294fb2d1, 0xdeb57086, 0x5f0fddb3, 0xeceda7ce, 0x4c87305f, 0x3a6d3307,
57 0xe22d2942, 0x9d060217, 0x1e42ed02, 0xb6f63b52, 0x4367f39f, 0x055cf262,
58 0x03a461b2, 0x5ef9e382, 0x386bc03a, 0x2a1e79c7, 0xf1a0058b, 0xd4d2dea9,
59 0x56baf37d, 0x5daff6cc, 0xf03a951d, 0xaef7de45, 0xa8f4581e, 0x3960b555,
60 0xffbfff6d, 0xbe702a23, 0x8f5b6d6f, 0x061739fb, 0x98696f47, 0x3fd596d4,
61 0x151eac6b, 0xa9fcc4f5, 0x69181a12, 0x3ac5a107, 0xb5198fe7, 0x96bcb1da,
62 0x1b5ddf8e, 0xc757d650, 0x65865c3a, 0x8fc0a41a, 0x87435536, 0x99eda6f2,
63 0x41874794, 0x29cff4e8, 0xb70efd9a, 0x3103f6e7, 0x84d2453b, 0x15a450bd,
64 0x74f49af1, 0x60f664b1, 0xa1c86935, 0xfdafbce1, 0xe36353e3, 0x5d9ba739,
65 0xbc0559ba, 0x708b0054, 0xd41d808c, 0xb2f31723, 0x9027c41f, 0xf136d165,
66 0xb5374b12, 0x9420a6ac, 0x273958b6, 0xe6c2fad0, 0xebdc1f21, 0xfb33af8b,
67 0xc71c25cd, 0xe9a2d8e5, 0xbeb38a50, 0xbceb7cc2, 0x4e4e73f0, 0xcd6c251d,
68 0xde4c032c, 0x4b04ac30, 0x725b8b21, 0x4eb8c33b, 0x20d07b75, 0x0567aa63,
69 0xb56b2bb7, 0xc1f5fd3a, 0xcafd35ca, 0x470dd4da, 0xfe4f94cd, 0xfb8de424,
70 0xe8dbcf40, 0xfe50a37a, 0x62db5b5d, 0xf32f4ab6, 0x2c4a8a51, 0x18473dc0,
71 0xfe0cbb6e, 0xfe399efd, 0xdf34ecc9, 0x6ccd5055, 0x46097073, 0x139135c2,
72 0x721c76f6, 0x1c6a94b4, 0x6eee014d, 0x8a508e02, 0x3da538f5, 0x280d394f,
73 0x5248a0c4, 0x3ce94c6c, 0x9a71ad3a, 0x8493dd05, 0xe43f0ab6, 0x18e4ed42,
74 0x6c5c0e09, 0x42b06ec9, 0x8d330343, 0xa45b6f59, 0x2a573c0c, 0xd7fd3de6,
75 0xeedeab68, 0x5c84dafc, 0xbbd1b1a8, 0xa3ce1ad1, 0x85b70bed, 0xb6add07f,
76 0xa531309c, 0x8f8ab852, 0x564de332, 0xeac9ed0c, 0x73da402c, 0x3ec52761,
77 0x43af2f4d, 0xd6ff45c8, 0x4c367462, 0xd553bd6a, 0x44724855, 0x3b2aa728,
78 0x56e5eb65, 0xeaf16173, 0x33fa42ff, 0xd714bb5d, 0xfbd0a3b9, 0xaf517134,
79 0x9416c8cd, 0x534cf94f, 0x548947c2, 0x34193569, 0x32f4389a, 0xfe7028bc,
80 0xed73b1ed, 0x9db95770, 0x468e3922, 0x0440c3cd, 0x60059a62, 0x33504562,
81 0x2b229fbd, 0x5174dca5, 0xf7028752, 0xd63c6aa8, 0x31276f38, 0x0646721c,
82 0xb0191da8, 0xe00e6de0, 0x9eac1a6e, 0x9f7628a5, 0xed6c06ea, 0x0bb8af15,
83 0xf119fb12, 0x38693c1c, 0x732bc0fe, 0x84953275, 0xb82ec888, 0x33a4f1b3,
84 0x3099835e, 0x028a8782, 0x5fdd51d7, 0xc6c717b3, 0xb06caf71, 0x17c8c111,
85 0x61bad754, 0x9fd03061, 0xe09df1af, 0x3bc9eb73, 0x85878413, 0x9889aaf2,
86 0x3f5a9e46, 0x42c9f01f, 0x9984a4f4, 0xd5de43cc, 0xd294daed, 0xbecba2d2,
87 0xf1f6e72c, 0x5551128a, 0x83af87e2, 0x6f0342ba,
90 static const struct got_error *addblk(struct got_delta_table *, FILE *,
91 uint8_t *, off_t, off_t, off_t, uint32_t);
94 hashblk(const unsigned char *p, off_t n, uint32_t seed)
96 return murmurhash2(p, n, seed);
99 static const struct got_error *
100 lookup(int *n, struct got_delta_table *dt, FILE *f, off_t file_offset0,
101 off_t len, off_t offset, uint32_t h)
103 struct got_delta_block *block;
104 uint8_t buf[GOT_DELTIFY_MAXCHUNK];
105 uint8_t buf2[GOT_DELTIFY_MAXCHUNK];
109 for (i = h % dt->size; dt->offs[i] != 0; i = (i + 1) % dt->size) {
110 block = &dt->blocks[dt->offs[i] - 1];
111 if (block->len != len || block->hash != h)
115 if (fseeko(f, file_offset0 + offset, SEEK_SET) == -1)
116 return got_error_from_errno("fseeko");
117 r = fread(buf, 1, len, f);
121 return got_ferror(f, GOT_ERR_IO);
125 if (fseeko(f, file_offset0 + block->offset, SEEK_SET) == -1)
126 return got_error_from_errno("fseeko");
127 if (fread(buf2, 1, len, f) != len)
128 return got_ferror(f, GOT_ERR_IO);
129 if (memcmp(buf, buf2, len) == 0)
137 static const struct got_error *
138 lookup_mem(int *n, struct got_delta_table *dt, uint8_t *basedata,
139 off_t basefile_offset0, uint8_t *p, off_t len, uint32_t h)
141 struct got_delta_block *block;
145 for (i = h % dt->size; dt->offs[i] != 0; i = (i + 1) % dt->size) {
146 block = &dt->blocks[dt->offs[i] - 1];
147 if (len == block->len && h == block->hash) {
148 d = basedata + basefile_offset0 + block->offset;
149 if (memcmp(d, p, len) == 0)
158 static const struct got_error *
159 resizeht(struct got_delta_table *dt, FILE *f, off_t offset0, uint8_t *data,
162 const struct got_error *err;
163 struct got_delta_block *b;
164 size_t newsize, oldsize;
167 if (dt->nblocks == dt->nalloc) {
168 newsize = dt->nalloc + 256;
169 b = reallocarray(dt->blocks, newsize, sizeof(*dt->blocks));
171 return got_error_from_errno("reallocarray");
173 dt->nalloc = newsize;
176 if (dt->blocks == NULL || dt->len * 100 / dt->size > 70) {
180 dt->offs = calloc(dt->size, sizeof(*dt->offs));
181 if (dt->offs == NULL) {
183 return got_error_from_errno("calloc");
186 for (i = 0; i < dt->nblocks; ++i) {
189 err = lookup(&n, dt, f, offset0, b->len,
192 err = lookup_mem(&n, dt, data, offset0,
193 data + b->offset, b->len, b->hash);
200 assert(dt->offs[n] == 0);
208 static const struct got_error *
209 addblk(struct got_delta_table *dt, FILE *f, uint8_t *data, off_t file_offset0,
210 off_t len, off_t offset, uint32_t h)
212 const struct got_error *err;
213 struct got_delta_block *block;
219 err = resizeht(dt, f, file_offset0, data, len);
224 err = lookup(&i, dt, f, file_offset0, len, offset, h);
226 err = lookup_mem(&i, dt, data, file_offset0, data + offset,
231 if (dt->offs[i] != 0)
232 return NULL; /* found */
234 dt->offs[i] = dt->nblocks + 1;
235 block = &dt->blocks[dt->nblocks];
237 block->offset = offset;
246 static const struct got_error *
247 lookupblk(struct got_delta_block **block, struct got_delta_table *dt,
248 unsigned char *p, off_t len, uint32_t seed, FILE *basefile,
249 off_t basefile_offset0)
253 uint8_t buf[GOT_DELTIFY_MAXCHUNK];
254 struct got_delta_block *b;
259 h = hashblk(p, len, seed);
261 for (i = h % dt->size; dt->offs[i] != 0; i = (i + 1) % dt->size) {
262 b = &dt->blocks[dt->offs[i] - 1];
263 if (b->hash != h || b->len != len)
265 if (fseeko(basefile, basefile_offset0 + b->offset,
267 return got_error_from_errno("fseeko");
268 r = fread(buf, 1, len, basefile);
270 return got_ferror(basefile, GOT_ERR_IO);
271 if (memcmp(p, buf, len) == 0) {
279 static const struct got_error *
280 lookupblk_mem(struct got_delta_block **block, struct got_delta_table *dt,
281 unsigned char *p, off_t len, uint32_t seed, uint8_t *basedata,
282 off_t basefile_offset0)
284 const struct got_error *err;
289 h = hashblk(p, len, seed);
290 err = lookup_mem(&n, dt, basedata, basefile_offset0, p, len, h);
293 if (dt->offs[n] != 0)
294 *block = &dt->blocks[dt->offs[n] - 1];
298 static const struct got_error *
299 nextblk(uint8_t *buf, off_t *blocklen, FILE *f)
302 const unsigned char *p;
304 off_t pos = ftello(f);
308 r = fread(buf, 1, GOT_DELTIFY_MAXCHUNK, f);
309 if (r == 0 && ferror(f))
310 return got_ferror(f, GOT_ERR_IO);
311 if (r < GOT_DELTIFY_MINCHUNK)
312 return NULL; /* no more delta-worthy blocks left */
314 /* Got a deltifiable block. Find the split-point where it ends. */
315 p = buf + GOT_DELTIFY_MINCHUNK;
317 while (p != buf + r) {
318 gh = (gh << 1) + geartab[*p++];
319 if ((gh & GOT_DELTIFY_SPLITMASK) == 0)
323 *blocklen = (p - buf);
324 if (fseeko(f, pos + *blocklen, SEEK_SET) == -1)
325 return got_error_from_errno("fseeko");
330 static const struct got_error *
331 nextblk_mem(off_t *blocklen, uint8_t *data, off_t fileoffset, off_t filesize)
334 const unsigned char *p;
338 if (fileoffset >= filesize ||
339 filesize - fileoffset < GOT_DELTIFY_MINCHUNK)
340 return NULL; /* no more delta-worthy blocks left */
342 /* Got a deltifiable block. Find the split-point where it ends. */
343 p = data + fileoffset + GOT_DELTIFY_MINCHUNK;
345 while (p != data + MIN(fileoffset + GOT_DELTIFY_MAXCHUNK, filesize)) {
346 gh = (gh << 1) + geartab[*p++];
347 if ((gh & GOT_DELTIFY_SPLITMASK) == 0)
351 *blocklen = (p - (data + fileoffset));
355 const struct got_error *
356 got_deltify_init(struct got_delta_table **dt, FILE *f, off_t fileoffset,
357 off_t filesize, uint32_t seed)
359 const struct got_error *err = NULL;
361 const off_t offset0 = fileoffset;
363 *dt = calloc(1, sizeof(**dt));
365 return got_error_from_errno("calloc");
369 (*dt)->blocks = calloc((*dt)->nalloc, sizeof(struct got_delta_block));
370 if ((*dt)->blocks == NULL) {
371 err = got_error_from_errno("calloc");
376 (*dt)->offs = calloc((*dt)->size, sizeof(*(*dt)->offs));
377 if ((*dt)->offs == NULL) {
378 err = got_error_from_errno("calloc");
382 if (fseeko(f, fileoffset, SEEK_SET) == -1)
383 return got_error_from_errno("fseeko");
385 while (fileoffset < filesize) {
386 uint8_t buf[GOT_DELTIFY_MAXCHUNK];
388 err = nextblk(buf, &blocklen, f);
393 h = hashblk(buf, blocklen, seed);
394 err = addblk(*dt, f, NULL, offset0, blocklen,
395 fileoffset - offset0, h);
398 fileoffset += blocklen;
399 if (fseeko(f, fileoffset, SEEK_SET) == -1)
400 return got_error_from_errno("fseeko");
412 const struct got_error *
413 got_deltify_init_mem(struct got_delta_table **dt, uint8_t *data,
414 off_t fileoffset, off_t filesize, uint32_t seed)
416 const struct got_error *err = NULL;
418 const off_t offset0 = fileoffset;
420 *dt = calloc(1, sizeof(**dt));
422 return got_error_from_errno("calloc");
426 (*dt)->blocks = calloc((*dt)->nalloc, sizeof(struct got_delta_block));
427 if ((*dt)->blocks == NULL) {
428 err = got_error_from_errno("calloc");
433 (*dt)->offs = calloc((*dt)->size, sizeof(*(*dt)->offs));
434 if ((*dt)->offs == NULL) {
435 err = got_error_from_errno("calloc");
439 while (fileoffset < filesize) {
441 err = nextblk_mem(&blocklen, data, fileoffset, filesize);
446 h = hashblk(data + fileoffset, blocklen, seed);
447 err = addblk(*dt, NULL, data, offset0, blocklen,
448 fileoffset - offset0, h);
451 fileoffset += blocklen;
464 got_deltify_free(struct got_delta_table *dt)
473 static const struct got_error *
474 emitdelta(struct got_delta_instruction **deltas, size_t *nalloc, int *ndeltas,
475 const size_t alloc_chunk_size, int copy, off_t offset, off_t len)
477 struct got_delta_instruction *d, *p;
479 if (*nalloc < *ndeltas + alloc_chunk_size) {
480 p = reallocarray(*deltas, *nalloc + alloc_chunk_size,
481 sizeof(struct got_delta_instruction));
483 return got_error_from_errno("reallocarray");
485 *nalloc += alloc_chunk_size;
488 d = &(*deltas)[*ndeltas - 1];
495 static const struct got_error *
496 stretchblk(FILE *basefile, off_t base_offset0, struct got_delta_block *block,
497 FILE *f, off_t filesize, off_t *blocklen)
499 uint8_t basebuf[GOT_DELTIFY_MAXCHUNK], buf[GOT_DELTIFY_MAXCHUNK];
503 if (fseeko(basefile, base_offset0 + block->offset + *blocklen,
505 return got_error_from_errno("fseeko");
507 while (buf_equal && *blocklen < (1 << 24) - 1) {
508 base_r = fread(basebuf, 1, sizeof(basebuf), basefile);
510 if (ferror(basefile))
511 return got_ferror(basefile, GOT_ERR_IO);
514 r = fread(buf, 1, sizeof(buf), f);
517 return got_ferror(f, GOT_ERR_IO);
520 for (i = 0; i < MIN(base_r, r); i++) {
521 if (buf[i] != basebuf[i]) {
532 static const struct got_error *
533 stretchblk_file_mem(uint8_t *basedata, off_t base_offset0, off_t basefile_size,
534 struct got_delta_block *block, FILE *f, off_t filesize, off_t *blocklen)
536 uint8_t buf[GOT_DELTIFY_MAXCHUNK];
539 off_t base_offset = base_offset0 + block->offset + *blocklen;
541 if (base_offset > basefile_size) {
542 return got_error_fmt(GOT_ERR_RANGE,
543 "read beyond the size of delta base at offset %lld",
544 (long long)base_offset);
547 while (buf_equal && *blocklen < (1 << 24) - 1) {
548 if (base_offset + *blocklen >= basefile_size)
550 r = fread(buf, 1, sizeof(buf), f);
553 return got_ferror(f, GOT_ERR_IO);
556 for (i = 0; i < MIN(basefile_size - base_offset, r); i++) {
557 if (buf[i] != *(basedata + base_offset + i)) {
568 static const struct got_error *
569 stretchblk_mem_file(FILE *basefile, off_t base_offset0,
570 struct got_delta_block *block, uint8_t *data, off_t fileoffset,
571 off_t filesize, off_t *blocklen)
573 uint8_t basebuf[GOT_DELTIFY_MAXCHUNK];
577 if (fileoffset > filesize) {
578 return got_error_fmt(GOT_ERR_RANGE,
579 "read beyond the size of deltify file at offset %lld",
580 (long long)fileoffset);
583 if (fseeko(basefile, base_offset0 + block->offset + *blocklen,
585 return got_error_from_errno("fseeko");
587 while (buf_equal && *blocklen < (1 << 24) - 1) {
588 if (fileoffset + *blocklen >= filesize)
590 base_r = fread(basebuf, 1, sizeof(basebuf), basefile);
592 if (ferror(basefile))
593 return got_ferror(basefile, GOT_ERR_IO);
596 for (i = 0; i < MIN(base_r, filesize - fileoffset); i++) {
597 if (*(data + fileoffset + i) != basebuf[i]) {
608 static const struct got_error *
609 stretchblk_mem_mem(uint8_t *basedata, off_t base_offset0, off_t basefile_size,
610 struct got_delta_block *block, uint8_t *data, off_t fileoffset,
611 off_t filesize, off_t *blocklen)
614 off_t base_offset = base_offset0 + block->offset + *blocklen;
617 if (base_offset > basefile_size) {
618 return got_error_fmt(GOT_ERR_RANGE,
619 "read beyond the size of delta base at offset %lld",
620 (long long)base_offset);
623 if (fileoffset > filesize) {
624 return got_error_fmt(GOT_ERR_RANGE,
625 "read beyond the size of deltify file at offset %lld",
626 (long long)fileoffset);
629 p = data + fileoffset;
630 q = basedata + base_offset;
631 maxlen = MIN(basefile_size - base_offset, filesize - fileoffset);
632 for (i = 0; i < maxlen && *blocklen < (1 << 24) - 1; i++) {
641 const struct got_error *
642 got_deltify(struct got_delta_instruction **deltas, int *ndeltas,
643 FILE *f, off_t fileoffset, off_t filesize, uint32_t seed,
644 struct got_delta_table *dt, FILE *basefile,
645 off_t basefile_offset0, off_t basefile_size)
647 const struct got_error *err = NULL;
648 const off_t offset0 = fileoffset;
650 const size_t alloc_chunk_size = 64;
656 * offset0 indicates where data to be deltified begins.
657 * For example, we want to avoid deltifying a Git object header at
658 * the beginning of the file.
660 if (fseeko(f, offset0, SEEK_SET) == -1)
661 return got_error_from_errno("fseeko");
663 *deltas = reallocarray(NULL, alloc_chunk_size,
664 sizeof(struct got_delta_instruction));
666 return got_error_from_errno("reallocarray");
667 nalloc = alloc_chunk_size;
669 while (fileoffset < filesize) {
670 uint8_t buf[GOT_DELTIFY_MAXCHUNK];
672 struct got_delta_block *block;
673 err = nextblk(buf, &blocklen, f);
677 /* Source remainder from the file itself. */
678 if (fileoffset < filesize) {
679 err = emitdelta(deltas, &nalloc, ndeltas,
680 alloc_chunk_size, 0, fileoffset - offset0,
681 filesize - fileoffset);
685 err = lookupblk(&block, dt, buf, blocklen, seed, basefile,
691 * We have found a matching block in the delta base.
692 * Attempt to stretch the block as far as possible and
693 * generate a copy instruction.
695 err = stretchblk(basefile, basefile_offset0, block,
696 f, filesize, &blocklen);
699 err = emitdelta(deltas, &nalloc, ndeltas,
700 alloc_chunk_size, 1, block->offset, blocklen);
706 * This block needs to be sourced from the file itself.
708 err = emitdelta(deltas, &nalloc, ndeltas,
709 alloc_chunk_size, 0, fileoffset - offset0, blocklen);
713 fileoffset += blocklen;
714 if (fseeko(f, fileoffset, SEEK_SET) == -1) {
715 err = got_error_from_errno("fseeko");
728 const struct got_error *
729 got_deltify_file_mem(struct got_delta_instruction **deltas, int *ndeltas,
730 FILE *f, off_t fileoffset, off_t filesize, uint32_t seed,
731 struct got_delta_table *dt, uint8_t *basedata,
732 off_t basefile_offset0, off_t basefile_size)
734 const struct got_error *err = NULL;
735 const off_t offset0 = fileoffset;
737 const size_t alloc_chunk_size = 64;
743 * offset0 indicates where data to be deltified begins.
744 * For example, we want to avoid deltifying a Git object header at
745 * the beginning of the file.
747 if (fseeko(f, offset0, SEEK_SET) == -1)
748 return got_error_from_errno("fseeko");
750 *deltas = reallocarray(NULL, alloc_chunk_size,
751 sizeof(struct got_delta_instruction));
753 return got_error_from_errno("reallocarray");
754 nalloc = alloc_chunk_size;
756 while (fileoffset < filesize) {
757 uint8_t buf[GOT_DELTIFY_MAXCHUNK];
759 struct got_delta_block *block;
760 err = nextblk(buf, &blocklen, f);
764 /* Source remainder from the file itself. */
765 if (fileoffset < filesize) {
766 err = emitdelta(deltas, &nalloc, ndeltas,
767 alloc_chunk_size, 0, fileoffset - offset0,
768 filesize - fileoffset);
772 err = lookupblk_mem(&block, dt, buf, blocklen, seed, basedata,
778 * We have found a matching block in the delta base.
779 * Attempt to stretch the block as far as possible and
780 * generate a copy instruction.
782 err = stretchblk_file_mem(basedata, basefile_offset0,
783 basefile_size, block, f, filesize, &blocklen);
786 err = emitdelta(deltas, &nalloc, ndeltas,
787 alloc_chunk_size, 1, block->offset, blocklen);
793 * This block needs to be sourced from the file itself.
795 err = emitdelta(deltas, &nalloc, ndeltas,
796 alloc_chunk_size, 0, fileoffset - offset0, blocklen);
800 fileoffset += blocklen;
801 if (fseeko(f, fileoffset, SEEK_SET) == -1) {
802 err = got_error_from_errno("fseeko");
815 const struct got_error *
816 got_deltify_mem_file(struct got_delta_instruction **deltas, int *ndeltas,
817 uint8_t *data, off_t fileoffset, off_t filesize, uint32_t seed,
818 struct got_delta_table *dt, FILE *basefile,
819 off_t basefile_offset0, off_t basefile_size)
821 const struct got_error *err = NULL;
822 const off_t offset0 = fileoffset;
824 const size_t alloc_chunk_size = 64;
829 *deltas = reallocarray(NULL, alloc_chunk_size,
830 sizeof(struct got_delta_instruction));
832 return got_error_from_errno("reallocarray");
833 nalloc = alloc_chunk_size;
835 while (fileoffset < filesize) {
837 struct got_delta_block *block;
838 err = nextblk_mem(&blocklen, data, fileoffset, filesize);
842 /* Source remainder from the file itself. */
843 if (fileoffset < filesize) {
844 err = emitdelta(deltas, &nalloc, ndeltas,
845 alloc_chunk_size, 0, fileoffset - offset0,
846 filesize - fileoffset);
850 err = lookupblk(&block, dt, data + fileoffset, blocklen, seed,
851 basefile, basefile_offset0);
856 * We have found a matching block in the delta base.
857 * Attempt to stretch the block as far as possible and
858 * generate a copy instruction.
860 err = stretchblk_mem_file(basefile, basefile_offset0,
861 block, data, fileoffset + blocklen, filesize,
865 err = emitdelta(deltas, &nalloc, ndeltas,
866 alloc_chunk_size, 1, block->offset, blocklen);
872 * This block needs to be sourced from the file itself.
874 err = emitdelta(deltas, &nalloc, ndeltas,
875 alloc_chunk_size, 0, fileoffset - offset0, blocklen);
879 fileoffset += blocklen;
890 const struct got_error *
891 got_deltify_mem_mem(struct got_delta_instruction **deltas, int *ndeltas,
892 uint8_t *data, off_t fileoffset, off_t filesize, uint32_t seed,
893 struct got_delta_table *dt, uint8_t *basedata,
894 off_t basefile_offset0, off_t basefile_size)
896 const struct got_error *err = NULL;
897 const off_t offset0 = fileoffset;
899 const size_t alloc_chunk_size = 64;
904 *deltas = reallocarray(NULL, alloc_chunk_size,
905 sizeof(struct got_delta_instruction));
907 return got_error_from_errno("reallocarray");
908 nalloc = alloc_chunk_size;
910 while (fileoffset < filesize) {
912 struct got_delta_block *block;
913 err = nextblk_mem(&blocklen, data, fileoffset, filesize);
917 /* Source remainder from the file itself. */
918 if (fileoffset < filesize) {
919 err = emitdelta(deltas, &nalloc, ndeltas,
920 alloc_chunk_size, 0, fileoffset - offset0,
921 filesize - fileoffset);
925 err = lookupblk_mem(&block, dt, data + fileoffset, blocklen,
926 seed, basedata, basefile_offset0);
931 * We have found a matching block in the delta base.
932 * Attempt to stretch the block as far as possible and
933 * generate a copy instruction.
935 err = stretchblk_mem_mem(basedata, basefile_offset0,
936 basefile_size, block, data, fileoffset + blocklen,
937 filesize, &blocklen);
940 err = emitdelta(deltas, &nalloc, ndeltas,
941 alloc_chunk_size, 1, block->offset, blocklen);
947 * This block needs to be sourced from the file itself.
949 err = emitdelta(deltas, &nalloc, ndeltas,
950 alloc_chunk_size, 0, fileoffset - offset0, blocklen);
954 fileoffset += blocklen;