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by Marek Habersack
Import upstream version 1.10 |
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/* base64-encode.c
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*
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*/
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/* nettle, low-level cryptographics library
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*
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* Copyright (C) 2002 Niels Möller
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*
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* The nettle library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or (at your
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* option) any later version.
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*
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* The nettle library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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* License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with the nettle library; see the file COPYING.LIB. If not, write to
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* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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* MA 02111-1307, USA.
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*/
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#if HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <assert.h> |
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#include <stdlib.h> |
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#include "base64.h" |
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#define TABLE_INVALID -1
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#define TABLE_SPACE -2
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#define TABLE_END -3
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/* FIXME: Make sure that all whitespace characters, SPC, HT, VT, FF,
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* CR and LF are ignored. */
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static const signed char |
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decode_table[0x100] = |
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{
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -1, -1, -2, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, |
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -3, -1, -1, |
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-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, |
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, |
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-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, |
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, |
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};
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void
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base64_decode_init(struct base64_decode_ctx *ctx) |
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{
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ctx->word = ctx->bits = ctx->padding = 0; |
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}
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int
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base64_decode_single(struct base64_decode_ctx *ctx, |
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uint8_t *dst, |
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uint8_t src) |
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{
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int data; |
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data = decode_table[src]; |
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switch(data) |
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{
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default: |
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assert(data >= 0 && data < 0x40); |
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if (ctx->padding) |
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return -1; |
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ctx->word = ctx->word << 6 | data; |
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ctx->bits += 6; |
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if (ctx->bits >= 8) |
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{
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ctx->bits -= 8; |
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dst[0] = ctx->word >> ctx->bits; |
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return 1; |
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}
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else return 0; |
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case TABLE_INVALID: |
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return -1; |
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case TABLE_SPACE: |
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return 0; |
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case TABLE_END: |
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/* There can be at most two padding characters. */
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if (!ctx->bits || ctx->padding > 2) |
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return -1; |
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if (ctx->word & ( (1<<ctx->bits) - 1)) |
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/* We shouldn't have any leftover bits */
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return -1; |
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ctx->padding++; |
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ctx->bits -= 2; |
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return 0; |
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}
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}
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int
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base64_decode_update(struct base64_decode_ctx *ctx, |
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unsigned *dst_length, |
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uint8_t *dst, |
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unsigned src_length, |
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const uint8_t *src) |
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{
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unsigned done; |
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unsigned i; |
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assert(*dst_length >= BASE64_DECODE_LENGTH(src_length)); |
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for (i = 0, done = 0; i<src_length; i++) |
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switch(base64_decode_single(ctx, dst + done, src[i])) |
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{
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case -1: |
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return 0; |
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case 1: |
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done++; |
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/* Fall through */
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case 0: |
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break; |
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default: |
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abort(); |
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}
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assert(done <= BASE64_DECODE_LENGTH(src_length)); |
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*dst_length = done; |
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return 1; |
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}
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int
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base64_decode_final(struct base64_decode_ctx *ctx) |
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{
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return ctx->bits == 0; |
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}
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