5 Author: Pekka Riikonen <priikone@silcnet.org>
7 Copyright (C) 2000 - 2005 Pekka Riikonen
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; version 2 of the License.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
20 #include "silccrypto.h"
22 /* Encodes MP integer into binary data. Returns allocated data that
23 must be free'd by the caller. If `len' is provided the destination
24 buffer is allocated that large. If zero then the size is approximated. */
26 unsigned char *silc_mp_mp2bin(SilcMPInt *val, SilcUInt32 len,
32 size = (len ? len : ((silc_mp_sizeinbase(val, 2) + 7) / 8));
33 ret = silc_calloc(size, sizeof(*ret));
37 silc_mp_mp2bin_noalloc(val, ret, size);
45 /* Samve as above but does not allocate any memory. The encoded data is
46 returned into `dst' and it's length to the `ret_len'. */
48 void silc_mp_mp2bin_noalloc(SilcMPInt *val, unsigned char *dst,
52 SilcUInt32 size = dst_len;
56 silc_mp_set(&tmp, val);
58 for (i = size; i > 0; i--) {
59 dst[i - 1] = (unsigned char)(silc_mp_get_ui(&tmp) & 0xff);
60 silc_mp_div_2exp(&tmp, &tmp, 8);
66 /* Decodes binary data into MP integer. The integer sent as argument
67 must be initialized. */
69 void silc_mp_bin2mp(unsigned char *data, SilcUInt32 len, SilcMPInt *ret)
73 silc_mp_set_ui(ret, 0);
75 for (i = 0; i < len; i++) {
76 silc_mp_mul_2exp(ret, ret, 8);
77 silc_mp_add_ui(ret, ret, data[i]);
81 /* MP integer encoding with silc_buffer_format. */
83 int silc_mp_format(SilcStack stack, SilcBuffer buffer,
84 void *value, void *context)
86 SilcMPInt *mp = value;
92 m = silc_mp_mp2bin(mp, 0, &m_len);
96 ret = silc_buffer_sformat(stack, buffer,
97 SILC_STR_UINT32(m_len),
98 SILC_STR_DATA(m, m_len),
106 /* MP integer decoding with silc_buffer_unformat. */
108 int silc_mp_unformat(SilcStack stack, SilcBuffer buffer,
109 void **value, void *context)
111 SilcMPInt *mp = *value;
116 ret = silc_buffer_sunformat(stack, buffer,
117 SILC_STR_UI32_NSTRING(&m, &m_len),
122 silc_mp_bin2mp(m, m_len, mp);