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https://github.com/ClassiCube/ClassiCube.git
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58 lines
1.6 KiB
C
58 lines
1.6 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_decode(uint32_t *x, const void *src, size_t len)
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{
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const unsigned char *buf;
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size_t u, v;
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uint32_t acc;
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int acc_len;
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buf = src;
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u = len;
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v = 1;
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acc = 0;
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acc_len = 0;
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while (u -- > 0) {
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uint32_t b;
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b = buf[u];
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acc |= (b << acc_len);
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acc_len += 8;
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if (acc_len >= 31) {
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x[v ++] = acc & (uint32_t)0x7FFFFFFF;
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acc_len -= 31;
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acc = b >> (8 - acc_len);
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}
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}
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if (acc_len != 0) {
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x[v ++] = acc;
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}
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x[0] = br_i31_bit_length(x + 1, v - 1);
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}
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