48 lines
1.6 KiB
C
48 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_ecdsa_i31_bits2int(uint32_t *x,
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const void *src, size_t len, uint32_t ebitlen)
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{
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uint32_t bitlen, hbitlen;
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int sc;
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bitlen = ebitlen - (ebitlen >> 5);
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hbitlen = (uint32_t)len << 3;
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if (hbitlen > bitlen) {
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len = (bitlen + 7) >> 3;
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sc = (int)((hbitlen - bitlen) & 7);
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} else {
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sc = 0;
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}
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br_i31_zero(x, ebitlen);
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br_i31_decode(x, src, len);
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br_i31_rshift(x, sc);
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x[0] = ebitlen;
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}
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