Added generic API for date range validation (with callbacks).
[BearSSL] / int / i32_encode.c
1 /*
2 * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25 #include "inner.h"
26
27 /* see inner.h */
28 void
29 br_i32_encode(void *dst, size_t len, const uint32_t *x)
30 {
31 unsigned char *buf;
32 size_t k;
33
34 buf = dst;
35
36 /*
37 * Compute the announced size of x in bytes; extra bytes are
38 * filled with zeros.
39 */
40 k = (x[0] + 7) >> 3;
41 while (len > k) {
42 *buf ++ = 0;
43 len --;
44 }
45
46 /*
47 * Now we use k as index within x[]. That index starts at 1;
48 * we initialize it to the topmost complete word, and process
49 * any remaining incomplete word.
50 */
51 k = (len + 3) >> 2;
52 switch (len & 3) {
53 case 3:
54 *buf ++ = x[k] >> 16;
55 /* fall through */
56 case 2:
57 *buf ++ = x[k] >> 8;
58 /* fall through */
59 case 1:
60 *buf ++ = x[k];
61 k --;
62 }
63
64 /*
65 * Encode all complete words.
66 */
67 while (k > 0) {
68 br_enc32be(buf, x[k]);
69 k --;
70 buf += 4;
71 }
72 }