commit - 5788893e052e36c9c54c8ab6781ed97a5fca6f91
commit + 69aa0e90839745f70c6fc7e33c78bbe949f3500d
blob - ae0934bc97fbc1d6580fa4db26df7f5b13306f70
blob + 8a0eff6fcacb802bbb187c60a24de4447dc455fe
--- lib/deltify.c
+++ lib/deltify.c
/*
* Copyright (c) 2020 Ori Bernstein
+ * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
#include <sys/queue.h>
#include <assert.h>
+#include <errno.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <sha1.h>
#include "got_error.h"
-#include "got_object.h"
-#include "got_lib_delta.h"
-#include "got_lib_object.h"
+#include "got_lib_deltify.h"
-struct Dblock {
- unsigned char *buf;
- int len;
- int off;
- uint64_t hash;
-};
+#ifndef MIN
+#define MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
+#endif
-struct Dtab {
- unsigned char *base;
- int nbase;
- struct Dblock *b;
- int nb;
- int sz;
-};
-
-struct Delta {
- int cpy;
- int off;
- int len;
-};
-
-enum {
- Minchunk = 128,
- Maxchunk = 8192,
- Splitmask = (1 << 8) - 1,
-
-};
-
static uint32_t geartab[] = {
- 0x67ed26b7, 0x32da500c, 0x53d0fee0, 0xce387dc7, 0xcd406d90, 0x2e83a4d4, 0x9fc9a38d, 0xb67259dc,
- 0xca6b1722, 0x6d2ea08c, 0x235cea2e, 0x3149bb5f, 0x1beda787, 0x2a6b77d5, 0x2f22d9ac, 0x91fc0544,
- 0xe413acfa, 0x5a30ff7a, 0xad6fdde0, 0x444fd0f5, 0x7ad87864, 0x58c5ff05, 0x8d2ec336, 0x2371f853,
- 0x550f8572, 0x6aa448dd, 0x7c9ddbcf, 0x95221e14, 0x2a82ec33, 0xcbec5a78, 0xc6795a0d, 0x243995b7,
- 0x1c909a2f, 0x4fded51c, 0x635d334b, 0x0e2b9999, 0x2702968d, 0x856de1d5, 0x3325d60e, 0xeb6a7502,
- 0xec2a9844, 0x0905835a, 0xa1820375, 0xa4be5cab, 0x96a6c058, 0x2c2ccd70, 0xba40fce3, 0xd794c46b,
- 0x8fbae83e, 0xc3aa7899, 0x3d3ff8ed, 0xa0d42b5b, 0x571c0c97, 0xd2811516, 0xf7e7b96c, 0x4fd2fcbd,
- 0xe2fdec94, 0x282cc436, 0x78e8e95c, 0x80a3b613, 0xcfbee20c, 0xd4a32d1c, 0x2a12ff13, 0x6af82936,
- 0xe5630258, 0x8efa6a98, 0x294fb2d1, 0xdeb57086, 0x5f0fddb3, 0xeceda7ce, 0x4c87305f, 0x3a6d3307,
- 0xe22d2942, 0x9d060217, 0x1e42ed02, 0xb6f63b52, 0x4367f39f, 0x055cf262, 0x03a461b2, 0x5ef9e382,
- 0x386bc03a, 0x2a1e79c7, 0xf1a0058b, 0xd4d2dea9, 0x56baf37d, 0x5daff6cc, 0xf03a951d, 0xaef7de45,
- 0xa8f4581e, 0x3960b555, 0xffbfff6d, 0xbe702a23, 0x8f5b6d6f, 0x061739fb, 0x98696f47, 0x3fd596d4,
- 0x151eac6b, 0xa9fcc4f5, 0x69181a12, 0x3ac5a107, 0xb5198fe7, 0x96bcb1da, 0x1b5ddf8e, 0xc757d650,
- 0x65865c3a, 0x8fc0a41a, 0x87435536, 0x99eda6f2, 0x41874794, 0x29cff4e8, 0xb70efd9a, 0x3103f6e7,
- 0x84d2453b, 0x15a450bd, 0x74f49af1, 0x60f664b1, 0xa1c86935, 0xfdafbce1, 0xe36353e3, 0x5d9ba739,
- 0xbc0559ba, 0x708b0054, 0xd41d808c, 0xb2f31723, 0x9027c41f, 0xf136d165, 0xb5374b12, 0x9420a6ac,
- 0x273958b6, 0xe6c2fad0, 0xebdc1f21, 0xfb33af8b, 0xc71c25cd, 0xe9a2d8e5, 0xbeb38a50, 0xbceb7cc2,
- 0x4e4e73f0, 0xcd6c251d, 0xde4c032c, 0x4b04ac30, 0x725b8b21, 0x4eb8c33b, 0x20d07b75, 0x0567aa63,
- 0xb56b2bb7, 0xc1f5fd3a, 0xcafd35ca, 0x470dd4da, 0xfe4f94cd, 0xfb8de424, 0xe8dbcf40, 0xfe50a37a,
- 0x62db5b5d, 0xf32f4ab6, 0x2c4a8a51, 0x18473dc0, 0xfe0cbb6e, 0xfe399efd, 0xdf34ecc9, 0x6ccd5055,
- 0x46097073, 0x139135c2, 0x721c76f6, 0x1c6a94b4, 0x6eee014d, 0x8a508e02, 0x3da538f5, 0x280d394f,
- 0x5248a0c4, 0x3ce94c6c, 0x9a71ad3a, 0x8493dd05, 0xe43f0ab6, 0x18e4ed42, 0x6c5c0e09, 0x42b06ec9,
- 0x8d330343, 0xa45b6f59, 0x2a573c0c, 0xd7fd3de6, 0xeedeab68, 0x5c84dafc, 0xbbd1b1a8, 0xa3ce1ad1,
- 0x85b70bed, 0xb6add07f, 0xa531309c, 0x8f8ab852, 0x564de332, 0xeac9ed0c, 0x73da402c, 0x3ec52761,
- 0x43af2f4d, 0xd6ff45c8, 0x4c367462, 0xd553bd6a, 0x44724855, 0x3b2aa728, 0x56e5eb65, 0xeaf16173,
- 0x33fa42ff, 0xd714bb5d, 0xfbd0a3b9, 0xaf517134, 0x9416c8cd, 0x534cf94f, 0x548947c2, 0x34193569,
- 0x32f4389a, 0xfe7028bc, 0xed73b1ed, 0x9db95770, 0x468e3922, 0x0440c3cd, 0x60059a62, 0x33504562,
- 0x2b229fbd, 0x5174dca5, 0xf7028752, 0xd63c6aa8, 0x31276f38, 0x0646721c, 0xb0191da8, 0xe00e6de0,
- 0x9eac1a6e, 0x9f7628a5, 0xed6c06ea, 0x0bb8af15, 0xf119fb12, 0x38693c1c, 0x732bc0fe, 0x84953275,
- 0xb82ec888, 0x33a4f1b3, 0x3099835e, 0x028a8782, 0x5fdd51d7, 0xc6c717b3, 0xb06caf71, 0x17c8c111,
- 0x61bad754, 0x9fd03061, 0xe09df1af, 0x3bc9eb73, 0x85878413, 0x9889aaf2, 0x3f5a9e46, 0x42c9f01f,
- 0x9984a4f4, 0xd5de43cc, 0xd294daed, 0xbecba2d2, 0xf1f6e72c, 0x5551128a, 0x83af87e2, 0x6f0342ba,
+ 0x67ed26b7, 0x32da500c, 0x53d0fee0, 0xce387dc7, 0xcd406d90, 0x2e83a4d4,
+ 0x9fc9a38d, 0xb67259dc, 0xca6b1722, 0x6d2ea08c, 0x235cea2e, 0x3149bb5f,
+ 0x1beda787, 0x2a6b77d5, 0x2f22d9ac, 0x91fc0544, 0xe413acfa, 0x5a30ff7a,
+ 0xad6fdde0, 0x444fd0f5, 0x7ad87864, 0x58c5ff05, 0x8d2ec336, 0x2371f853,
+ 0x550f8572, 0x6aa448dd, 0x7c9ddbcf, 0x95221e14, 0x2a82ec33, 0xcbec5a78,
+ 0xc6795a0d, 0x243995b7, 0x1c909a2f, 0x4fded51c, 0x635d334b, 0x0e2b9999,
+ 0x2702968d, 0x856de1d5, 0x3325d60e, 0xeb6a7502, 0xec2a9844, 0x0905835a,
+ 0xa1820375, 0xa4be5cab, 0x96a6c058, 0x2c2ccd70, 0xba40fce3, 0xd794c46b,
+ 0x8fbae83e, 0xc3aa7899, 0x3d3ff8ed, 0xa0d42b5b, 0x571c0c97, 0xd2811516,
+ 0xf7e7b96c, 0x4fd2fcbd, 0xe2fdec94, 0x282cc436, 0x78e8e95c, 0x80a3b613,
+ 0xcfbee20c, 0xd4a32d1c, 0x2a12ff13, 0x6af82936, 0xe5630258, 0x8efa6a98,
+ 0x294fb2d1, 0xdeb57086, 0x5f0fddb3, 0xeceda7ce, 0x4c87305f, 0x3a6d3307,
+ 0xe22d2942, 0x9d060217, 0x1e42ed02, 0xb6f63b52, 0x4367f39f, 0x055cf262,
+ 0x03a461b2, 0x5ef9e382, 0x386bc03a, 0x2a1e79c7, 0xf1a0058b, 0xd4d2dea9,
+ 0x56baf37d, 0x5daff6cc, 0xf03a951d, 0xaef7de45, 0xa8f4581e, 0x3960b555,
+ 0xffbfff6d, 0xbe702a23, 0x8f5b6d6f, 0x061739fb, 0x98696f47, 0x3fd596d4,
+ 0x151eac6b, 0xa9fcc4f5, 0x69181a12, 0x3ac5a107, 0xb5198fe7, 0x96bcb1da,
+ 0x1b5ddf8e, 0xc757d650, 0x65865c3a, 0x8fc0a41a, 0x87435536, 0x99eda6f2,
+ 0x41874794, 0x29cff4e8, 0xb70efd9a, 0x3103f6e7, 0x84d2453b, 0x15a450bd,
+ 0x74f49af1, 0x60f664b1, 0xa1c86935, 0xfdafbce1, 0xe36353e3, 0x5d9ba739,
+ 0xbc0559ba, 0x708b0054, 0xd41d808c, 0xb2f31723, 0x9027c41f, 0xf136d165,
+ 0xb5374b12, 0x9420a6ac, 0x273958b6, 0xe6c2fad0, 0xebdc1f21, 0xfb33af8b,
+ 0xc71c25cd, 0xe9a2d8e5, 0xbeb38a50, 0xbceb7cc2, 0x4e4e73f0, 0xcd6c251d,
+ 0xde4c032c, 0x4b04ac30, 0x725b8b21, 0x4eb8c33b, 0x20d07b75, 0x0567aa63,
+ 0xb56b2bb7, 0xc1f5fd3a, 0xcafd35ca, 0x470dd4da, 0xfe4f94cd, 0xfb8de424,
+ 0xe8dbcf40, 0xfe50a37a, 0x62db5b5d, 0xf32f4ab6, 0x2c4a8a51, 0x18473dc0,
+ 0xfe0cbb6e, 0xfe399efd, 0xdf34ecc9, 0x6ccd5055, 0x46097073, 0x139135c2,
+ 0x721c76f6, 0x1c6a94b4, 0x6eee014d, 0x8a508e02, 0x3da538f5, 0x280d394f,
+ 0x5248a0c4, 0x3ce94c6c, 0x9a71ad3a, 0x8493dd05, 0xe43f0ab6, 0x18e4ed42,
+ 0x6c5c0e09, 0x42b06ec9, 0x8d330343, 0xa45b6f59, 0x2a573c0c, 0xd7fd3de6,
+ 0xeedeab68, 0x5c84dafc, 0xbbd1b1a8, 0xa3ce1ad1, 0x85b70bed, 0xb6add07f,
+ 0xa531309c, 0x8f8ab852, 0x564de332, 0xeac9ed0c, 0x73da402c, 0x3ec52761,
+ 0x43af2f4d, 0xd6ff45c8, 0x4c367462, 0xd553bd6a, 0x44724855, 0x3b2aa728,
+ 0x56e5eb65, 0xeaf16173, 0x33fa42ff, 0xd714bb5d, 0xfbd0a3b9, 0xaf517134,
+ 0x9416c8cd, 0x534cf94f, 0x548947c2, 0x34193569, 0x32f4389a, 0xfe7028bc,
+ 0xed73b1ed, 0x9db95770, 0x468e3922, 0x0440c3cd, 0x60059a62, 0x33504562,
+ 0x2b229fbd, 0x5174dca5, 0xf7028752, 0xd63c6aa8, 0x31276f38, 0x0646721c,
+ 0xb0191da8, 0xe00e6de0, 0x9eac1a6e, 0x9f7628a5, 0xed6c06ea, 0x0bb8af15,
+ 0xf119fb12, 0x38693c1c, 0x732bc0fe, 0x84953275, 0xb82ec888, 0x33a4f1b3,
+ 0x3099835e, 0x028a8782, 0x5fdd51d7, 0xc6c717b3, 0xb06caf71, 0x17c8c111,
+ 0x61bad754, 0x9fd03061, 0xe09df1af, 0x3bc9eb73, 0x85878413, 0x9889aaf2,
+ 0x3f5a9e46, 0x42c9f01f, 0x9984a4f4, 0xd5de43cc, 0xd294daed, 0xbecba2d2,
+ 0xf1f6e72c, 0x5551128a, 0x83af87e2, 0x6f0342ba,
};
static uint64_t
-hash(unsigned char *p, int n)
+hashblk(const unsigned char *p, off_t n)
{
unsigned char buf[SHA1_DIGEST_LENGTH];
uint64_t h;
- SHA1Data(p, n, buf);
+ SHA1_CTX ctx;
+ SHA1Init(&ctx);
+ SHA1Update(&ctx, p, n);
+ SHA1Final(buf, &ctx);
memcpy(&h, buf, sizeof(h));
return be64toh(h);
}
static const struct got_error *
-addblk(struct Dtab *dt, void *buf, int len, int off, uint64_t h)
+addblk(struct got_delta_table *dt, FILE *f, off_t len, off_t offset, uint64_t h)
{
- int i, sz, probe;
- struct Dblock *db;
+ const struct got_error *err = NULL;
+ int i, nalloc;
+ uint8_t buf[GOT_DELTIFY_MAXCHUNK];
+ size_t r = 0;
- probe = h % dt->sz;
- while (dt->b[probe].buf != NULL) {
- if (len == dt->b[probe].len &&
- memcmp(buf, dt->b[probe].buf, len) == 0)
- return NULL;
- probe = (probe + 1) % dt->sz;
+ if (len == 0)
+ return NULL;
+
+ i = h % dt->nalloc;
+ while (dt->blocks[i].len != 0) {
+ if (r == 0) {
+ if (fseeko(f, offset, SEEK_SET) == -1)
+ return got_error_from_errno("fseeko");
+ r = fread(buf, 1, len, f);
+ if (r != len) {
+ if (ferror(f))
+ return got_ferror(f, GOT_ERR_IO);
+ return NULL;
+ }
+ }
+ /*
+ * Avoid adding duplicate blocks.
+ * NB: A matching hash is insufficient for detecting equality.
+ * The hash can only detect inequality, so only check 'len'.
+ */
+ if (len == dt->blocks[i].len) {
+ uint8_t buf2[GOT_DELTIFY_MAXCHUNK];
+ if (fseeko(f, dt->blocks[i].offset, SEEK_SET) == -1)
+ return got_error_from_errno("fseeko");
+ if (fread(buf2, 1, len, f) != len)
+ return got_ferror(f, GOT_ERR_IO);
+ if (memcmp(buf, buf2, len) == 0)
+ return NULL;
+ }
+
+ i = (i + 1) % dt->nalloc;
}
- assert(dt->b[probe].buf == NULL);
- dt->b[probe].buf = buf;
- dt->b[probe].len = len;
- dt->b[probe].off = off;
- dt->b[probe].hash = h;
- dt->nb++;
- if (dt->sz < 2 * dt->nb) {
- sz = dt->sz;
- db = dt->b;
- dt->sz *= 2;
- dt->nb = 0;
- dt->b = calloc(dt->sz, sizeof(struct Dblock));
- if (dt->b == NULL)
- return got_error_from_errno("calloc");
- for (i = 0; i < sz; i++) {
- if (db[i].buf != NULL)
- return addblk(dt, db[i].buf, db[i].len,
- db[i].off, db[i].hash);
+ assert(dt->blocks[i].len == 0);
+ dt->blocks[i].len = len;
+ dt->blocks[i].offset = offset;
+ dt->blocks[i].hash = h;
+ dt->nblocks++;
+ if (dt->nalloc < 2 * dt->nblocks) {
+ struct got_delta_block *db;
+ nalloc = dt->nalloc * 2;
+ db = dt->blocks;
+ dt->blocks = calloc(nalloc, sizeof(struct got_delta_block));
+ if (dt->blocks == NULL) {
+ err = got_error_from_errno("calloc");
+ dt->blocks = db;
+ return err;
}
+ dt->nalloc = nalloc;
+ /*
+ * Recompute all block positions. Hash-based indices of blocks
+ * in the array depend on the allocated length of the array.
+ */
+ dt->nblocks = 0;
+ for (i = 0; i < nalloc; i++) {
+ if (db[i].len == 0)
+ continue;
+ err = addblk(dt, f, db[i].len, db[i].offset,
+ db[i].hash);
+ if (err)
+ break;
+ }
free(db);
}
- return NULL;
+ return err;
}
-static struct Dblock *
-lookup(struct Dtab *dt, unsigned char *p, int n)
+static const struct got_error *
+lookupblk(struct got_delta_block **block, struct got_delta_table *dt,
+ unsigned char *p, off_t len, FILE *basefile)
{
- int probe;
+ int i;
uint64_t h;
+ uint8_t buf[GOT_DELTIFY_MAXCHUNK];
+ size_t r;
- h = hash(p, n);
- for (probe = h % dt->sz; dt->b[probe].buf != NULL;
- probe = (probe + 1) % dt->sz) {
- if (dt->b[probe].hash != h)
+ *block = NULL;
+
+ h = hashblk(p, len);
+ for (i = h % dt->nalloc; dt->blocks[i].len != 0;
+ i = (i + 1) % dt->nalloc) {
+ if (dt->blocks[i].hash != h ||
+ dt->blocks[i].len != len)
continue;
- if (n != dt->b[probe].len)
- continue;
- if (memcmp(p, dt->b[probe].buf, n) != 0)
- continue;
- return &dt->b[probe];
+ if (fseeko(basefile, dt->blocks[i].offset, SEEK_SET) == -1)
+ return got_error_from_errno("fseeko");
+ r = fread(buf, 1, len, basefile);
+ if (r != len)
+ return got_ferror(basefile, GOT_ERR_IO);
+ if (memcmp(p, buf, len) == 0) {
+ *block = &dt->blocks[i];
+ break;
+ }
}
return NULL;
}
-static int
-nextblk(unsigned char *s, unsigned char *e)
+static const struct got_error *
+nextblk(uint8_t *buf, off_t *blocklen, FILE *f)
{
uint32_t gh;
- unsigned char *p;
+ const unsigned char *p;
+ size_t r;
+ off_t pos = ftello(f);
- if ((e - s) < Minchunk)
- return e - s;
- p = s + Minchunk;
- if ((e - s) > Maxchunk)
- e = s + Maxchunk;
- gh = 0;
- while (p != e) {
+ *blocklen = 0;
+
+ r = fread(buf, 1, GOT_DELTIFY_MAXCHUNK, f);
+ if (r == 0 && ferror(f))
+ return got_ferror(f, GOT_ERR_IO);
+ if (r < GOT_DELTIFY_MINCHUNK)
+ return NULL; /* no more delta-worthy blocks left */
+
+ /* Got a deltifiable block. Find the split-point where it ends. */
+ p = buf + GOT_DELTIFY_MINCHUNK;
+ gh = 0;
+ while (p != buf + r) {
gh = (gh << 1) + geartab[*p++];
- if ((gh & Splitmask) == 0)
+ if ((gh & GOT_DELTIFY_SPLITMASK) == 0)
break;
}
- return p - s;
+
+ *blocklen = (p - buf);
+ if (fseeko(f, pos + *blocklen, SEEK_SET) == -1)
+ return got_error_from_errno("fseeko");
+
+ return NULL;
}
const struct got_error *
-dtinit(struct Dtab *dt, struct got_object *obj)
+got_deltify_init(struct got_delta_table **dt, FILE *f, off_t fileoffset,
+ off_t filesize)
{
- unsigned char *s = NULL, *e;
+ const struct got_error *err = NULL;
uint64_t h;
- long n, o;
-
- o = 0;
-#ifdef notyet
- s = (unsigned char *)obj->data;
-#endif
- e = s + obj->size;
- dt->nb = 0;
- dt->sz = 128;
- dt->b = calloc(dt->sz, sizeof(struct Dblock));
- if (dt->b == NULL)
+
+ *dt = calloc(1, sizeof(**dt));
+ if (*dt == NULL)
return got_error_from_errno("calloc");
-#ifdef notyet
- dt->base = (unsigned char *)obj->data;
-#endif
- dt->nbase = obj->size;
- while (s != e) {
- n = nextblk(s, e);
- h = hash(s, n);
- addblk(dt, s, n, o, h);
- s += n;
- o += n;
+
+ (*dt)->nblocks = 0;
+ (*dt)->nalloc = 128;
+ (*dt)->blocks = calloc((*dt)->nalloc, sizeof(struct got_delta_block));
+ if ((*dt)->blocks == NULL) {
+ err = got_error_from_errno("calloc");
+ goto done;
}
- return NULL;
+ if (fseeko(f, fileoffset, SEEK_SET) == -1)
+ return got_error_from_errno("fseeko");
+
+ while (fileoffset < filesize) {
+ uint8_t buf[GOT_DELTIFY_MAXCHUNK];
+ off_t blocklen;
+ err = nextblk(buf, &blocklen, f);
+ if (err)
+ goto done;
+ if (blocklen == 0)
+ break;
+ h = hashblk(buf, blocklen);
+ err = addblk(*dt, f, blocklen, fileoffset, h);
+ if (err)
+ goto done;
+ fileoffset += blocklen;
+ }
+done:
+ if (err) {
+ free((*dt)->blocks);
+ free(*dt);
+ *dt = NULL;
+ }
+
+ return err;
}
void
-dtclear(struct Dtab *dt)
+got_deltify_free(struct got_delta_table *dt)
{
- free(dt->b);
+ free(dt->blocks);
+ free(dt);
}
static const struct got_error *
-emitdelta(struct Delta **pd, int *nd, int cpy, int off, int len)
+emitdelta(struct got_delta_instruction **deltas, int *ndeltas, int copy,
+ off_t offset, off_t len)
{
- struct Delta *d, *p;
+ struct got_delta_instruction *d, *p;
- *nd += 1;
- p = reallocarray(*pd, *nd, sizeof(struct Delta));
+ *ndeltas += 1;
+ p = reallocarray(*deltas, *ndeltas,
+ sizeof(struct got_delta_instruction));
if (p == NULL)
return got_error_from_errno("realloc");
- *pd = p;
- d = &(*pd)[*nd - 1];
- d->cpy = cpy;
- d->off = off;
+ *deltas = p;
+ d = &(*deltas)[*ndeltas - 1];
+ d->copy = copy;
+ d->offset = offset;
d->len = len;
return NULL;
}
-static int
-stretch(struct Dtab *dt, struct Dblock *b, unsigned char *s,
- unsigned char *e, int n)
+static const struct got_error *
+stretchblk(FILE *basefile, struct got_delta_block *block, FILE *f,
+ off_t filesize, off_t *blocklen)
{
- unsigned char *p, *q, *eb;
+ uint8_t basebuf[GOT_DELTIFY_MAXCHUNK], buf[GOT_DELTIFY_MAXCHUNK];
+ size_t base_r, r, i;
+ off_t orig_blocklen = *blocklen;
+ off_t pos = ftello(f);
+ int buf_equal = 1;
- if (b == NULL)
- return n;
- p = s + n;
- q = dt->base + b->off + n;
- eb = dt->base + dt->nbase;
- while (n < (1 << 24) - 1) {
- if (p == e || q == eb)
+ if (fseeko(basefile, block->offset, SEEK_SET) == -1)
+ return got_error_from_errno("fseeko");
+
+ while (buf_equal && *blocklen < (1 << 24) - 1) {
+ base_r = fread(basebuf, 1, sizeof(basebuf), basefile);
+ if (base_r == 0) {
+ if (ferror(basefile))
+ return got_ferror(basefile, GOT_ERR_IO);
break;
- if (*p != *q)
+ }
+ r = fread(buf, 1, sizeof(buf), f);
+ if (r == 0) {
+ if (ferror(f))
+ return got_ferror(f, GOT_ERR_IO);
break;
- p++;
- q++;
- n++;
+ }
+ for (i = 0; i < MIN(base_r, r); i++) {
+ if (buf[i] != basebuf[i]) {
+ buf_equal = 0;
+ break;
+ }
+ (*blocklen)++;
+ }
}
- return n;
+
+ if (fseeko(f, pos + *blocklen - orig_blocklen, SEEK_SET) == -1)
+ return got_error_from_errno("fseeko");
+
+ return NULL;
}
-struct Delta *
-deltify(struct got_object *obj, struct Dtab *dt, int *pnd)
+const struct got_error *
+got_deltify(struct got_delta_instruction **deltas, int *ndeltas,
+ FILE *f, off_t fileoffset, off_t filesize,
+ struct got_delta_table *dt, FILE *basefile,
+ off_t basefile_size)
{
- struct Delta *d;
- struct Dblock *b;
- unsigned char *s = NULL, *e;
- long n, o;
-
- o = 0;
- d = NULL;
-#ifdef notyet
- s = (unsigned char *)obj->data;
-#endif
- e = s + obj->size;
- *pnd = 0;
- while (s != e) {
- n = nextblk(s, e);
- b = lookup(dt, s, n);
- n = stretch(dt, b, s, e, n);
- if (b != NULL)
- emitdelta(&d, pnd, 1, b->off, n);
- else
- emitdelta(&d, pnd, 0, o, n);
- s += n;
- o += n;
+ const struct got_error *err = NULL;
+ const off_t offset0 = fileoffset;
+
+ *deltas = NULL;
+ *ndeltas = 0;
+
+ /*
+ * offset0 indicates where data to be deltified begins.
+ * For example, we want to avoid deltifying a Git object header at
+ * the beginning of the file.
+ */
+ if (fseeko(f, offset0, SEEK_SET) == -1)
+ return got_error_from_errno("fseeko");
+
+ while (fileoffset < filesize) {
+ uint8_t buf[GOT_DELTIFY_MAXCHUNK];
+ off_t blocklen;
+ struct got_delta_block *block;
+ err = nextblk(buf, &blocklen, f);
+ if (err)
+ break;
+ if (blocklen == 0)
+ break;
+ err = lookupblk(&block, dt, buf, blocklen, basefile);
+ if (err)
+ break;
+ if (block != NULL) {
+ /*
+ * We have found a matching block in the delta base.
+ * Attempt to stretch the block as far as possible and
+ * generate a copy instruction.
+ */
+ err = stretchblk(basefile, block, f, filesize,
+ &blocklen);
+ if (err)
+ break;
+ emitdelta(deltas, ndeltas, 1, block->offset, blocklen);
+ } else {
+ /*
+ * No match.
+ * This block needs to be sourced from the file itself.
+ */
+ emitdelta(deltas, ndeltas, 0, fileoffset - offset0,
+ blocklen);
+ }
+ fileoffset += blocklen;
}
- return d;
+
+ if (err) {
+ free(*deltas);
+ *deltas = NULL;
+ *ndeltas = 0;
+ }
+ return err;
}
blob - /dev/null
blob + 39069a604eca508347a2f734e6fe70185a3febea (mode 644)
--- /dev/null
+++ lib/got_lib_deltify.h
+/*
+ * Copyright (c) 2020 Ori Bernstein
+ * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+struct got_delta_block {
+ off_t len;
+ off_t offset;
+ uint64_t hash;
+};
+
+struct got_delta_table {
+ struct got_delta_block *blocks;
+ int nblocks;
+ int nalloc;
+};
+
+struct got_delta_instruction {
+ int copy;
+ off_t offset;
+ off_t len;
+};
+
+enum {
+ GOT_DELTIFY_MINCHUNK = 128,
+ GOT_DELTIFY_MAXCHUNK = 8192,
+ GOT_DELTIFY_SPLITMASK = (1 << 8) - 1,
+
+};
+
+const struct got_error *got_deltify_init(struct got_delta_table **dt, FILE *f,
+ off_t fileoffset, off_t filesize);
+const struct got_error *got_deltify(struct got_delta_instruction **deltas,
+ int *ndeltas, FILE *f, off_t fileoffset, off_t filesize,
+ struct got_delta_table *dt, FILE *basefile, off_t basefile_size);
+void got_deltify_free(struct got_delta_table *dt);
