From c8bae7493d2f2910b57f13ded012e86bdcfb0532 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 16:47:53 +0200 Subject: Adding upstream version 1:2.39.2. Signed-off-by: Daniel Baumann --- patch-delta.c | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 94 insertions(+) create mode 100644 patch-delta.c (limited to 'patch-delta.c') diff --git a/patch-delta.c b/patch-delta.c new file mode 100644 index 0000000..b5c8594 --- /dev/null +++ b/patch-delta.c @@ -0,0 +1,94 @@ +/* + * patch-delta.c: + * recreate a buffer from a source and the delta produced by diff-delta.c + * + * (C) 2005 Nicolas Pitre + * + * This code is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include "git-compat-util.h" +#include "delta.h" + +void *patch_delta(const void *src_buf, unsigned long src_size, + const void *delta_buf, unsigned long delta_size, + unsigned long *dst_size) +{ + const unsigned char *data, *top; + unsigned char *dst_buf, *out, cmd; + unsigned long size; + + if (delta_size < DELTA_SIZE_MIN) + return NULL; + + data = delta_buf; + top = (const unsigned char *) delta_buf + delta_size; + + /* make sure the orig file size matches what we expect */ + size = get_delta_hdr_size(&data, top); + if (size != src_size) + return NULL; + + /* now the result size */ + size = get_delta_hdr_size(&data, top); + dst_buf = xmallocz(size); + + out = dst_buf; + while (data < top) { + cmd = *data++; + if (cmd & 0x80) { + unsigned long cp_off = 0, cp_size = 0; +#define PARSE_CP_PARAM(bit, var, shift) do { \ + if (cmd & (bit)) { \ + if (data >= top) \ + goto bad_length; \ + var |= ((unsigned) *data++ << (shift)); \ + } } while (0) + PARSE_CP_PARAM(0x01, cp_off, 0); + PARSE_CP_PARAM(0x02, cp_off, 8); + PARSE_CP_PARAM(0x04, cp_off, 16); + PARSE_CP_PARAM(0x08, cp_off, 24); + PARSE_CP_PARAM(0x10, cp_size, 0); + PARSE_CP_PARAM(0x20, cp_size, 8); + PARSE_CP_PARAM(0x40, cp_size, 16); +#undef PARSE_CP_PARAM + if (cp_size == 0) cp_size = 0x10000; + if (unsigned_add_overflows(cp_off, cp_size) || + cp_off + cp_size > src_size || + cp_size > size) + goto bad_length; + memcpy(out, (char *) src_buf + cp_off, cp_size); + out += cp_size; + size -= cp_size; + } else if (cmd) { + if (cmd > size || cmd > top - data) + goto bad_length; + memcpy(out, data, cmd); + out += cmd; + data += cmd; + size -= cmd; + } else { + /* + * cmd == 0 is reserved for future encoding + * extensions. In the mean time we must fail when + * encountering them (might be data corruption). + */ + error("unexpected delta opcode 0"); + goto bad; + } + } + + /* sanity check */ + if (data != top || size != 0) { + bad_length: + error("delta replay has gone wild"); + bad: + free(dst_buf); + return NULL; + } + + *dst_size = out - dst_buf; + return dst_buf; +} -- cgit v1.2.3