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/*
* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "inner.h"
/* see inner.h */
void
br_i31_encode(void *dst, size_t len, const uint32_t *x)
{
unsigned char *buf;
size_t k, xlen;
uint32_t acc;
int acc_len;
xlen = (x[0] + 31) >> 5;
if (xlen == 0) {
memset(dst, 0, len);
return;
}
buf = (unsigned char *)dst + len;
k = 1;
acc = 0;
acc_len = 0;
while (len != 0) {
uint32_t w;
w = (k <= xlen) ? x[k] : 0;
k ++;
if (acc_len == 0) {
acc = w;
acc_len = 31;
} else {
uint32_t z;
z = acc | (w << acc_len);
acc_len --;
acc = w >> (31 - acc_len);
if (len >= 4) {
buf -= 4;
len -= 4;
br_enc32be(buf, z);
} else {
switch (len) {
case 3:
buf[-3] = (unsigned char)(z >> 16);
/* fall through */
case 2:
buf[-2] = (unsigned char)(z >> 8);
/* fall through */
case 1:
buf[-1] = (unsigned char)z;
break;
}
return;
}
}
}
}
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