| 13 | #include "delta.h" |
| 14 | |
| 15 | void *patch_delta(const void *src_buf, size_t src_size, |
| 16 | const void *delta_buf, size_t delta_size, |
| 17 | size_t *dst_size) |
| 18 | { |
| 19 | const unsigned char *data, *top; |
| 20 | unsigned char *dst_buf, *out, cmd; |
| 21 | size_t size; |
| 22 | |
| 23 | if (delta_size < DELTA_SIZE_MIN) |
| 24 | return NULL; |
| 25 | |
| 26 | data = delta_buf; |
| 27 | top = (const unsigned char *) delta_buf + delta_size; |
| 28 | |
| 29 | /* make sure the orig file size matches what we expect */ |
| 30 | size = get_delta_hdr_size(&data, top); |
| 31 | if (size != src_size) |
| 32 | return NULL; |
| 33 | |
| 34 | /* now the result size */ |
| 35 | size = get_delta_hdr_size(&data, top); |
| 36 | dst_buf = xmallocz(size); |
| 37 | |
| 38 | out = dst_buf; |
| 39 | while (data < top) { |
| 40 | cmd = *data++; |
| 41 | if (cmd & 0x80) { |
| 42 | unsigned long cp_off = 0, cp_size = 0; |
| 43 | #define PARSE_CP_PARAM(bit, var, shift) do { \ |
| 44 | if (cmd & (bit)) { \ |
| 45 | if (data >= top) \ |
| 46 | goto bad_length; \ |
| 47 | var |= ((unsigned) *data++ << (shift)); \ |
| 48 | } } while (0) |
| 49 | PARSE_CP_PARAM(0x01, cp_off, 0); |
| 50 | PARSE_CP_PARAM(0x02, cp_off, 8); |
| 51 | PARSE_CP_PARAM(0x04, cp_off, 16); |
| 52 | PARSE_CP_PARAM(0x08, cp_off, 24); |
| 53 | PARSE_CP_PARAM(0x10, cp_size, 0); |
| 54 | PARSE_CP_PARAM(0x20, cp_size, 8); |
| 55 | PARSE_CP_PARAM(0x40, cp_size, 16); |
| 56 | #undef PARSE_CP_PARAM |
| 57 | if (cp_size == 0) cp_size = 0x10000; |
| 58 | if (unsigned_add_overflows(cp_off, cp_size) || |
| 59 | cp_off + cp_size > src_size || |
| 60 | cp_size > size) |
| 61 | goto bad_length; |
| 62 | memcpy(out, (char *) src_buf + cp_off, cp_size); |
| 63 | out += cp_size; |
| 64 | size -= cp_size; |
| 65 | } else if (cmd) { |
| 66 | if (cmd > size || cmd > top - data) |
| 67 | goto bad_length; |
| 68 | memcpy(out, data, cmd); |
| 69 | out += cmd; |
| 70 | data += cmd; |
| 71 | size -= cmd; |
| 72 | } else { |