GCC Code Coverage Report

Directory: src/
File: src/mpq-md5.c
Date: 2026-10-06 13:47:41
Exec Total Coverage
Lines: 59 59 100.0%
Functions: 4 4 100.0%
Branches: 18 18 100.0%
Line Branch Exec Source
1 /*
2 * mpq-md5.c -- MD5 checksums for MPQ format compatibility.
3 *
4 * Copyright (c) 2003-2026 Maik Broemme <mbroemme@libmpq.org>
5 *
6 * This file is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU Lesser General Public License as published by
8 * the Free Software Foundation; either version 2.1 of the License, or
9 * (at your option) any later version.
10 *
11 * This file is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public License
17 * along with this file; if not, see <https://www.gnu.org/licenses/>.
18 */
19
20 #include "mpq-md5.h"
21 #include "mpq-endian.h"
22
23 #include <string.h>
24
25 /*
26 * Transform one complete block using fixed-width unsigned arithmetic.
27 * Explicit little-endian loads make the result independent of host byte order.
28 */
29 static void
30 132613 transform(mpq_md5_s *context, const uint8_t block[64])
31 {
32 static const uint32_t constants[64] = {
33 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a, 0xa8304613,
34 0xfd469501, 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193,
35 0xa679438e, 0x49b40821, 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, 0xd62f105d,
36 0x02441453, 0xd8a1e681, 0xe7d3fbc8, 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
37 0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122,
38 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70, 0x289b7ec6, 0xeaa127fa,
39 0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, 0xf4292244,
40 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
41 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb,
42 0xeb86d391
43 };
44 static const uint8_t shifts[16] = { 7, 12, 17, 22, 5, 9, 14, 20, 4, 11, 16, 23, 6, 10, 15, 21 };
45 uint32_t words[16];
46 132613 uint32_t a = context->state[0];
47 132613 uint32_t b = context->state[1];
48 132613 uint32_t c = context->state[2];
49 132613 uint32_t d = context->state[3];
50 uint32_t i;
51
52
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 2254421 for (i = 0; i < 16; ++i)
53 2121808 words[i] = libmpq__load_le32(block + 4 * i);
54
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 8619845 for (i = 0; i < 64; ++i) {
55 uint32_t f;
56 uint32_t index;
57 uint32_t value;
58 8487232 uint32_t previous = d;
59 8487232 uint8_t shift = shifts[(i / 16) * 4 + i % 4];
60
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 8487232 if (i < 16) {
61 2121808 f = (b & c) | (~b & d);
62 2121808 index = i;
63
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 6365424 } else if (i < 32) {
64 2121808 f = (d & b) | (~d & c);
65 2121808 index = (5 * i + 1) % 16;
66
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 4243616 } else if (i < 48) {
67 2121808 f = b ^ c ^ d;
68 2121808 index = (3 * i + 5) % 16;
69 } else {
70 2121808 f = c ^ (b | ~d);
71 2121808 index = (7 * i) % 16;
72 }
73 8487232 value = a + f + constants[i] + words[index];
74 8487232 d = c;
75 8487232 c = b;
76 8487232 b += (value << shift) | (value >> (32 - shift));
77 8487232 a = previous;
78 }
79 132613 context->state[0] += a;
80 132613 context->state[1] += b;
81 132613 context->state[2] += c;
82 132613 context->state[3] += d;
83 132613 }
84
85 /*
86 * Initialize a caller-owned incremental checksum context.
87 * No allocation or external cryptographic provider is needed.
88 */
89 void
90 2980 libmpq__md5_init(mpq_md5_s *context)
91 {
92 2980 memset(context, 0, sizeof(*context));
93 2980 context->state[0] = 0x67452301;
94 2980 context->state[1] = 0xefcdab89;
95 2980 context->state[2] = 0x98badcfe;
96 2980 context->state[3] = 0x10325476;
97 2980 }
98
99 /*
100 * Add bytes to the checksum, buffering at most one incomplete block.
101 * The byte count wraps modulo 2^64 as required for the encoded bit length.
102 */
103 void
104 15617 libmpq__md5_update(mpq_md5_s *context, const uint8_t *data, size_t size)
105 {
106
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 154969 while (size != 0) {
107 139352 size_t used = (size_t)(context->size % 64);
108 139352 size_t take = size < 64 - used ? size : 64 - used;
109 139352 memcpy(context->buffer + used, data, take);
110 139352 context->size += take;
111 139352 data += take;
112 139352 size -= take;
113
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 139352 if (context->size % 64 == 0)
114 132613 transform(context, context->buffer);
115 }
116 15617 }
117
118 /*
119 * Append RFC padding and return the canonical sixteen-byte digest.
120 * Finalization consumes the context and clears its buffered input.
121 */
122 void
123 2963 libmpq__md5_final(mpq_md5_s *context, uint8_t digest[LIBMPQ_MD5_SIZE])
124 {
125 2963 uint8_t padding[64] = { 0x80 };
126 uint8_t length[8];
127 2963 size_t used = (size_t)(context->size % 64);
128 uint32_t i;
129
130 2963 libmpq__store_le64(length, context->size * 8);
131
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 2963 libmpq__md5_update(context, padding, used < 56 ? 56 - used : 120 - used);
132 2963 libmpq__md5_update(context, length, sizeof(length));
133
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 14815 for (i = 0; i < 4; ++i)
134 11852 libmpq__store_le32(digest + i * 4, context->state[i]);
135 2963 memset(context, 0, sizeof(*context));
136 2963 }
137