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