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/*
* basE91 encoding/decoding routines
*
* Copyright (c) 2000-2006 Joachim Henke
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of Joachim Henke nor the names of his contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "base91.h"
const unsigned char enctab[91] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '!', '#', '$',
'%', '&', '(', ')', '*', '+', ',', '.', '/', ':', ';', '<', '=',
'>', '?', '@', '[', ']', '^', '_', '`', '{', '|', '}', '~', '"'
};
const unsigned char dectab[256] = {
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 62, 90, 63, 64, 65, 66, 91, 67, 68, 69, 70, 71, 91, 72, 73,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 74, 75, 76, 77, 78, 79,
80, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 81, 91, 82, 83, 84,
85, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 86, 87, 88, 89, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91
};
void basE91_init(struct basE91 *b)
{
b->queue = 0;
b->nbits = 0;
b->val = -1;
}
size_t basE91_encode(struct basE91 *b, const void *i, size_t len, void *o)
{
const unsigned char *ib = i;
unsigned char *ob = o;
size_t n = 0;
while (len--) {
b->queue |= *ib++ << b->nbits;
b->nbits += 8;
if (b->nbits > 13) { /* enough bits in queue */
unsigned int val = b->queue & 8191;
if (val > 88) {
b->queue >>= 13;
b->nbits -= 13;
} else { /* we can take 14 bits */
val = b->queue & 16383;
b->queue >>= 14;
b->nbits -= 14;
}
ob[n++] = enctab[val % 91];
ob[n++] = enctab[val / 91];
}
}
return n;
}
/* process remaining bits from bit queue; write up to 2 bytes */
size_t basE91_encode_end(struct basE91 *b, void *o)
{
unsigned char *ob = o;
size_t n = 0;
if (b->nbits) {
ob[n++] = enctab[b->queue % 91];
if (b->nbits > 7 || b->queue > 90)
ob[n++] = enctab[b->queue / 91];
}
b->queue = 0;
b->nbits = 0;
b->val = -1;
return n;
}
size_t basE91_decode(struct basE91 *b, const void *i, size_t len, void *o)
{
const unsigned char *ib = i;
unsigned char *ob = o;
size_t n = 0;
unsigned int d;
while (len--) {
d = dectab[*ib++];
if (d == 91)
continue; /* ignore non-alphabet chars */
if (b->val == -1)
b->val = d; /* start next value */
else {
b->val += d * 91;
b->queue |= b->val << b->nbits;
b->nbits += (b->val & 8191) > 88 ? 13 : 14;
do {
ob[n++] = b->queue;
b->queue >>= 8;
b->nbits -= 8;
} while (b->nbits > 7);
b->val = -1; /* mark value complete */
}
}
return n;
}
/* process remaining bits; write at most 1 byte */
size_t basE91_decode_end(struct basE91 *b, void *o)
{
unsigned char *ob = o;
size_t n = 0;
if (b->val != -1)
ob[n++] = b->queue | b->val << b->nbits;
b->queue = 0;
b->nbits = 0;
b->val = -1;
return n;
}
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