1/*
2 * Copyright (c) 2018 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 */
28br_asn1_uint
29br_asn1_uint_prepare(const void *xdata, size_t xlen)
30{
31	const unsigned char *x;
32	br_asn1_uint t;
33
34	x = xdata;
35	while (xlen > 0 && *x == 0) {
36		x ++;
37		xlen --;
38	}
39	t.data = x;
40	t.len = xlen;
41	t.asn1len = xlen;
42	if (xlen == 0 || x[0] >= 0x80) {
43		t.asn1len ++;
44	}
45	return t;
46}
47
48/* see inner.h */
49size_t
50br_asn1_encode_length(void *dest, size_t len)
51{
52	unsigned char *buf;
53	size_t z;
54	int i, j;
55
56	buf = dest;
57	if (len < 0x80) {
58		if (buf != NULL) {
59			*buf = len;
60		}
61		return 1;
62	}
63	i = 0;
64	for (z = len; z != 0; z >>= 8) {
65		i ++;
66	}
67	if (buf != NULL) {
68		*buf ++ = 0x80 + i;
69		for (j = i - 1; j >= 0; j --) {
70			*buf ++ = len >> (j << 3);
71		}
72	}
73	return i + 1;
74}
75
76/* see inner.h */
77size_t
78br_asn1_encode_uint(void *dest, br_asn1_uint pp)
79{
80	unsigned char *buf;
81	size_t lenlen;
82
83	if (dest == NULL) {
84		return 1 + br_asn1_encode_length(NULL, pp.asn1len) + pp.asn1len;
85	}
86	buf = dest;
87	*buf ++ = 0x02;
88	lenlen = br_asn1_encode_length(buf, pp.asn1len);
89	buf += lenlen;
90	*buf = 0x00;
91	memcpy(buf + pp.asn1len - pp.len, pp.data, pp.len);
92	return 1 + lenlen + pp.asn1len;
93}
94