diff options
| -rw-r--r-- | base16-decode.c | 127 | ||||
| -rw-r--r-- | base16-encode.c | 54 | ||||
| -rw-r--r-- | base16-meta.c | 64 | ||||
| -rw-r--r-- | base16.h | 91 |
4 files changed, 336 insertions, 0 deletions
diff --git a/base16-decode.c b/base16-decode.c new file mode 100644 index 00000000..a5e6185c --- /dev/null +++ b/base16-decode.c @@ -0,0 +1,127 @@ +/* base16-encode.c + * + * Hex decoding. + */ + +/* nettle, low-level cryptographics library + * + * Copyright (C) 2002 Niels Möller + * + * The nettle library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or (at your + * option) any later version. + * + * The nettle library is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public + * License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the nettle library; see the file COPYING.LIB. If not, write to + * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + * MA 02111-1307, USA. + */ + +#include "base16.h" + +#include <assert.h> +#include <stdlib.h> + +void +base16_decode_init(struct base16_decode_ctx *ctx) +{ + ctx->word = ctx->bits = 0; +} + +enum { HEX_INVALID = -1, HEX_SPACE=-2 }; + +static const signed char +hex_decode_table[0x80] = + { + -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, + -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + }; + +/* Decodes a single byte. Returns amount of output (0 or 1), or -1 on + * errors. */ +int +base16_decode_single(struct base16_decode_ctx *ctx, + uint8_t *dst, + uint8_t src) +{ + int digit; + + if (src >= 0x80) + return -1; + + /* FIXME: This code could use more clever choices of constants. */ + digit = hex_decode_table[src]; + switch (digit) + { + case -1: + return -1; + case -2: + return 0; + default: + assert(digit >= 0); + assert(digit < 0x10); + + if (ctx->bits) + { + *dst = (ctx->word << 4) | digit; + ctx->bits = 0; + return 1; + } + else + { + ctx->word = digit; + ctx->bits = 4; + return 0; + } + } +} + +int +base16_decode_update(struct base16_decode_ctx *ctx, + unsigned *dst_length, + uint8_t *dst, + unsigned src_length, + const uint8_t *src) +{ + unsigned done; + unsigned i; + + assert(*dst_length >= BASE16_DECODE_LENGTH(src_length)); + + for (i = 0, done = 0; i<src_length; i++) + switch(base16_decode_single(ctx, dst + done, src[i])) + { + case -1: + return 0; + case 1: + done++; + /* Fall through */ + case 0: + break; + default: + abort(); + } + + assert(done <= BASE16_DECODE_LENGTH(src_length)); + + *dst_length = done; + return 1; +} + +int +base16_decode_final(struct base16_decode_ctx *ctx) +{ + return ctx->bits == 0; +} diff --git a/base16-encode.c b/base16-encode.c new file mode 100644 index 00000000..48ce3006 --- /dev/null +++ b/base16-encode.c @@ -0,0 +1,54 @@ +/* base16-encode.c + * + * Hex encoding. + */ + +/* nettle, low-level cryptographics library + * + * Copyright (C) 2002 Niels Möller + * + * The nettle library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or (at your + * option) any later version. + * + * The nettle library is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public + * License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the nettle library; see the file COPYING.LIB. If not, write to + * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + * MA 02111-1307, USA. + */ + +#include "base16.h" + + +static const uint8_t +hex_digits[16] = "0123456789abcdef"; + +#define DIGIT(x) (hex_digits[(x) & 0xf]) + +/* FIXME: Is this really needed? */ +/* Encodes a single byte. Always stores two digits in dst[0] and dst[1]. */ +void +base16_encode_single(uint8_t *dst, + uint8_t src) +{ + dst[0] = DIGIT(src/0x10); + dst[1] = DIGIT(src); +} + +/* Always stores BASE16_ENCODE_LENGTH(length) digits in dst. */ +void +base16_encode_update(uint8_t *dst, + unsigned length, + const uint8_t *src) +{ + unsigned i; + + for (i = 0, dst; i<length; i++, dst += 2) + base16_encode_single(dst, src[i]); +} diff --git a/base16-meta.c b/base16-meta.c new file mode 100644 index 00000000..ebfb7e25 --- /dev/null +++ b/base16-meta.c @@ -0,0 +1,64 @@ +/* base16-meta.c */ + +/* nettle, low-level cryptographics library + * + * Copyright (C) 2002 Niels Möller + * + * The nettle library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or (at your + * option) any later version. + * + * The nettle library is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public + * License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the nettle library; see the file COPYING.LIB. If not, write to + * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + * MA 02111-1307, USA. + */ + +#include "nettle-meta.h" + +#include "base16.h" + +/* Same as the macros with the same name */ +static unsigned +base16_encode_length(unsigned length) +{ + return BASE16_ENCODE_LENGTH(length); +} + +static unsigned +base16_decode_length(unsigned length) +{ + return BASE16_DECODE_LENGTH(length); +} + +static void +base16_encode_init(void *ctx) +{ (void) ctx; } + +static unsigned +base16_encode_update_wrapper(void *ctx, uint8_t *dst, + unsigned length, const uint8_t *src) +{ + (void) ctx; + + base16_encode_update(dst, length, src); + return BASE16_ENCODE_LENGTH(length); +} + +#define base16_encode_update base16_encode_update_wrapper + +static unsigned +base16_encode_final(void *ctx, uint8_t *dst) +{ (void) ctx; (void) dst; return 0; } + + +#define BASE16_ENCODE_FINAL_LENGTH 0 + +const struct nettle_armor nettle_base16 += _NETTLE_ARMOR_0(base16, BASE16); diff --git a/base16.h b/base16.h new file mode 100644 index 00000000..b00bc869 --- /dev/null +++ b/base16.h @@ -0,0 +1,91 @@ +/* base16.h + * + * Hex encoding and decoding, following spki conventions (i.e. + * allowing whitespace between digits). + */ + +/* nettle, low-level cryptographics library + * + * Copyright (C) 2002 Niels Möller + * + * The nettle library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or (at your + * option) any later version. + * + * The nettle library is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public + * License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with the nettle library; see the file COPYING.LIB. If not, write to + * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + * MA 02111-1307, USA. + */ + +#ifndef NETTLE_BASE16_H_INCLUDED +#define NETTLE_BASE16_H_INCLUDED + +#include <inttypes.h> + + +/* Base16 encoding */ + +/* Maximum length of output for base16_encode_update. */ +#define BASE16_ENCODE_LENGTH(length) ((length) * 2) + +/* Encodes a single byte. Always stores two digits in dst[0] and dst[1]. */ +void +base16_encode_single(uint8_t *dst, + uint8_t src); + +/* Always stores BASE16_ENCODE_LENGTH(length) digits in dst. */ +void +base16_encode_update(uint8_t *dst, + unsigned length, + const uint8_t *src); + + +/* Base16 decoding */ + +/* Maximum length of output for base16_decode_update. */ +/* We have at most 4 buffered bits, and a total of (length + 1) * 4 bits. */ +#define BASE16_DECODE_LENGTH(length) (((length) + 1) / 2) + +struct base16_decode_ctx +{ + unsigned word; /* Leftover bits */ + unsigned bits; /* Number buffered bits */ +}; + +void +base16_decode_init(struct base16_decode_ctx *ctx); + +/* Decodes a single byte. Returns amount of output (0 or 1), or -1 on + * errors. */ +int +base16_decode_single(struct base16_decode_ctx *ctx, + uint8_t *dst, + uint8_t src); + +/* Returns 1 on success, 0 on error. DST should point to an area of + * size at least BASE16_DECODE_LENGTH(length), and for sanity + * checking, *DST_LENGTH should be initialized to the size of that + * area before the call. *DST_LENGTH is updated to the amount of + * decoded output. */ + +/* FIXME: Currently results in an assertion failure if *DST_LENGTH is + * too small. Return some error instead? */ +int +base16_decode_update(struct base16_decode_ctx *ctx, + unsigned *dst_length, + uint8_t *dst, + unsigned src_length, + const uint8_t *src); + +/* Returns 1 on success. */ +int +base16_decode_final(struct base16_decode_ctx *ctx); + +#endif /* NETTLE_BASE16_H_INCLUDED */ |