1 /* $NetBSD: h_hexdump_r.c,v 1.1 2024/04/28 14:39:22 rillig Exp $ */
2
3 /*
4 * Copyright (c) 2024 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code was contributed to The NetBSD Foundation by Roland Illig.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
22 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 /* Given the output from "hexdump -C", reconstruct the original file. */
32
33 #include <err.h>
34 #include <inttypes.h>
35 #include <regex.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <string.h>
39
40 #define H "[0-9a-f]"
41 #define HH " (" H H ")"
42
43 static off_t off, noff;
44 static unsigned char prev_bytes[16], bytes[16], zeroes[16];
45
46 int
main(void)47 main(void)
48 {
49 char line[81];
50 regex_t data_re, end_re;
51 regmatch_t m[18];
52
53 if (regcomp(&data_re, "^(" H "{8,9})"
54 " " HH HH HH HH HH HH HH HH " " HH HH HH HH HH HH HH HH
55 " \\|.{16}\\|$", REG_EXTENDED) != 0)
56 err(1, "regcomp");
57 if (regcomp(&end_re, "^(" H "{8,9})$", REG_EXTENDED) != 0)
58 err(1, "regcomp");
59
60 while (fgets(line, sizeof(line), stdin) != NULL) {
61 line[strcspn(line, "\n")] = '\0';
62
63 if (strcmp(line, "*") == 0)
64 continue;
65
66 if (regexec(&data_re, line, 18, m, 0) == 0) {
67 noff = (off_t)strtoimax(line + m[1].rm_so, NULL, 16);
68 for (size_t i = 0; i < 16; i++)
69 bytes[i] = (unsigned char)strtoumax(
70 line + m[2 + i].rm_so, NULL, 16);
71
72 } else if (regexec(&end_re, line, 2, m, 0) == 0) {
73 noff = (off_t)strtoimax(line + m[1].rm_so, NULL, 16);
74 if (off < noff) {
75 if (fseeko(stdout, noff - 16, SEEK_SET) != 0)
76 err(1, "fseeko");
77 if (fwrite(prev_bytes, 1, 16, stdout) != 16)
78 err(1, "fwrite");
79 }
80 } else
81 err(1, "invalid line '%s'", line);
82
83 if (memcmp(prev_bytes, zeroes, 16) != 0) {
84 while (off < noff) {
85 if (fwrite(prev_bytes, 1, 16, stdout) != 16)
86 err(1, "fwrite");
87 off += 16;
88 }
89 if (off != noff)
90 err(1, "off");
91 } else {
92 if (fseeko(stdout, noff, SEEK_SET) != 0)
93 err(1, "fseeko");
94 off = noff;
95 }
96
97 memcpy(prev_bytes, bytes, 16);
98 }
99 return 0;
100 }
101