1 /* 2 * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org> 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining 5 * a copy of this software and associated documentation files (the 6 * "Software"), to deal in the Software without restriction, including 7 * without limitation the rights to use, copy, modify, merge, publish, 8 * distribute, sublicense, and/or sell copies of the Software, and to 9 * permit persons to whom the Software is furnished to do so, subject to 10 * the following conditions: 11 * 12 * The above copyright notice and this permission notice shall be 13 * included in all copies or substantial portions of the Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 18 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 19 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 20 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 21 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 22 * SOFTWARE. 23 */ 24 25 #include "inner.h" 26 27 /* see inner.h */ 28 void 29 br_i15_encode(void *dst, size_t len, const uint16_t *x) 30 { 31 unsigned char *buf; 32 size_t u, xlen; 33 uint32_t acc; 34 int acc_len; 35 36 xlen = (x[0] + 15) >> 4; 37 if (xlen == 0) { 38 memset(dst, 0, len); 39 return; 40 } 41 u = 1; 42 acc = 0; 43 acc_len = 0; 44 buf = dst; 45 while (len -- > 0) { 46 if (acc_len < 8) { 47 if (u <= xlen) { 48 acc += (uint32_t)x[u ++] << acc_len; 49 } 50 acc_len += 15; 51 } 52 buf[len] = (unsigned char)acc; 53 acc >>= 8; 54 acc_len -= 8; 55 } 56 } 57