include/nettle/base16.h

0001 /* base16.h
0002
0003    Hex encoding and decoding, following spki conventions (i.e.
0004    allowing whitespace between digits).
0005
0006    Copyright (C) 2002 Niels Möller
0007
0008    This file is part of GNU Nettle.
0009
0010    GNU Nettle is free software: you can redistribute it and/or
0011    modify it under the terms of either:
0012
0013      * the GNU Lesser General Public License as published by the Free
0014        Software Foundation; either version 3 of the License, or (at your
0015        option) any later version.
0016
0017    or
0018
0019      * the GNU General Public License as published by the Free
0020        Software Foundation; either version 2 of the License, or (at your
0021        option) any later version.
0022
0023    or both in parallel, as here.
0024
0025    GNU Nettle is distributed in the hope that it will be useful,
0026    but WITHOUT ANY WARRANTY; without even the implied warranty of
0027    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
0028    General Public License for more details.
0029
0030    You should have received copies of the GNU General Public License and
0031    the GNU Lesser General Public License along with this program.  If
0032    not, see http://www.gnu.org/licenses/.
0033 */
0034
0035 #ifndef NETTLE_BASE16_H_INCLUDED
0036 #define NETTLE_BASE16_H_INCLUDED
0037
0038 #include "nettle-types.h"
0039
0040 #ifdef __cplusplus
0041 extern "C" {
0042 #endif
0043
0044 /* Name mangling */
0045 #define base16_encode_single nettle_base16_encode_single
0046 #define base16_encode_update nettle_base16_encode_update
0047 #define base16_decode_init nettle_base16_decode_init
0048 #define base16_decode_single nettle_base16_decode_single
0049 #define base16_decode_update nettle_base16_decode_update
0050 #define base16_decode_final nettle_base16_decode_final
0051
0052 /* Base16 encoding */
0053
0054 /* Maximum length of output for base16_encode_update. */
0055 #define BASE16_ENCODE_LENGTH(length) ((length) * 2)
0056
0057 /* Encodes a single byte. Always stores two digits in dst[0] and dst[1]. */
0058 void
0059 base16_encode_single(char *dst,
0060              uint8_t src);
0061
0062 /* Always stores BASE16_ENCODE_LENGTH(length) digits in dst. */
0063 void
0064 base16_encode_update(char *dst,
0065              size_t length,
0066              const uint8_t *src);
0067
0068
0069 /* Base16 decoding */
0070
0071 /* Maximum length of output for base16_decode_update. */
0072 /* We have at most 4 buffered bits, and a total of (length + 1) * 4 bits. */
0073 #define BASE16_DECODE_LENGTH(length) (((length) + 1) / 2)
0074
0075 struct base16_decode_ctx
0076 {
0077   unsigned char word; /* Leftover bits */
0078   unsigned char bits; /* Number buffered bits */
0079 };
0080
0081 void
0082 base16_decode_init(struct base16_decode_ctx *ctx);
0083
0084 /* Decodes a single byte. Returns amount of output (0 or 1), or -1 on
0085  * errors. */
0086 int
0087 base16_decode_single(struct base16_decode_ctx *ctx,
0088              uint8_t *dst,
0089              char src);
0090
0091 /* Returns 1 on success, 0 on error. DST should point to an area of
0092  * size at least BASE16_DECODE_LENGTH(length). The amount of data
0093  * generated is returned in *DST_LENGTH. */
0094
0095 int
0096 base16_decode_update(struct base16_decode_ctx *ctx,
0097              size_t *dst_length,
0098              uint8_t *dst,
0099              size_t src_length,
0100              const char *src);
0101
0102 /* Returns 1 on success. */
0103 int
0104 base16_decode_final(struct base16_decode_ctx *ctx);
0105
0106 #ifdef __cplusplus
0107 }
0108 #endif
0109
0110 #endif /* NETTLE_BASE16_H_INCLUDED */