mirror of
https://github.com/cryb-to/cryb-to.git
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102 lines
3.2 KiB
C
102 lines
3.2 KiB
C
/*-
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* Copyright (c) 2013-2014 The University of Oslo
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "cryb/impl.h"
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#include <errno.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <cryb/rfc4648.h>
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static const char b32enc[] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
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/*
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* Encode data in RFC 4648 base 32 representation. The target buffer must
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* have room for base32_enclen(len) characters and a terminating NUL.
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*/
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int
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base32_encode(const uint8_t *in, size_t ilen, char *out, size_t *olen)
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{
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uint64_t bits;
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if (*olen <= base32_enclen(ilen)) {
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*olen = base32_enclen(ilen) + 1;
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errno = ENOSPC;
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return (-1);
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}
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*olen = base32_enclen(ilen) + 1;
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while (ilen >= 5) {
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bits = 0;
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bits |= (uint64_t)*in++ << 32;
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bits |= (uint64_t)*in++ << 24;
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bits |= (uint64_t)*in++ << 16;
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bits |= (uint64_t)*in++ << 8;
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bits |= (uint64_t)*in++;
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*out++ = b32enc[bits >> 35 & 0x1f];
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*out++ = b32enc[bits >> 30 & 0x1f];
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*out++ = b32enc[bits >> 25 & 0x1f];
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*out++ = b32enc[bits >> 20 & 0x1f];
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*out++ = b32enc[bits >> 15 & 0x1f];
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*out++ = b32enc[bits >> 10 & 0x1f];
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*out++ = b32enc[bits >> 5 & 0x1f];
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*out++ = b32enc[bits & 0x1f];
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ilen -= 5;
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}
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if (ilen > 0) {
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bits = 0;
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switch (ilen) {
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case 4:
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bits |= (uint64_t)in[3] << 8;
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/* fall through */
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case 3:
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bits |= (uint64_t)in[2] << 16;
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/* fall through */
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case 2:
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bits |= (uint64_t)in[1] << 24;
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/* fall through */
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case 1:
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bits |= (uint64_t)in[0] << 32;
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break;
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CRYB_NO_DEFAULT_CASE;
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}
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*out++ = b32enc[bits >> 35 & 0x1f];
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*out++ = b32enc[bits >> 30 & 0x1f];
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*out++ = ilen > 1 ? b32enc[bits >> 25 & 0x1f] : '=';
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*out++ = ilen > 1 ? b32enc[bits >> 20 & 0x1f] : '=';
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*out++ = ilen > 2 ? b32enc[bits >> 15 & 0x1f] : '=';
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*out++ = ilen > 3 ? b32enc[bits >> 10 & 0x1f] : '=';
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*out++ = ilen > 3 ? b32enc[bits >> 5 & 0x1f] : '=';
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*out++ = '=';
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}
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*out++ = '\0';
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return (0);
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}
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