1 /* 2 * Copyright (c) 2016 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_i32_encode(void *dst, size_t len, const uint32_t *x) 30 { 31 unsigned char *buf; 32 size_t k; 33 34 buf = dst; 35 36 /* 37 * Compute the announced size of x in bytes; extra bytes are 38 * filled with zeros. 39 */ 40 k = (x[0] + 7) >> 3; 41 while (len > k) { 42 *buf ++ = 0; 43 len --; 44 } 45 46 /* 47 * Now we use k as index within x[]. That index starts at 1; 48 * we initialize it to the topmost complete word, and process 49 * any remaining incomplete word. 50 */ 51 k = (len + 3) >> 2; 52 switch (len & 3) { 53 case 3: 54 *buf ++ = x[k] >> 16; 55 /* fall through */ 56 case 2: 57 *buf ++ = x[k] >> 8; 58 /* fall through */ 59 case 1: 60 *buf ++ = x[k]; 61 k --; 62 } 63 64 /* 65 * Encode all complete words. 66 */ 67 while (k > 0) { 68 br_enc32be(buf, x[k]); 69 k --; 70 buf += 4; 71 } 72 } 73