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 "brssl.h" 26 27 /* 28 * Prepare a vector buffer for adding 'extra' elements. 29 * buf current buffer 30 * esize size of a vector element 31 * ptr pointer to the 'ptr' vector field 32 * len pointer to the 'len' vector field 33 * extra number of elements to add 34 * 35 * If the buffer must be enlarged, then this function allocates the new 36 * buffer and releases the old one. The new buffer address is then returned. 37 * If the buffer needs not be enlarged, then the buffer address is returned. 38 * 39 * In case of enlargement, the 'len' field is adjusted accordingly. The 40 * 'ptr' field is not modified. 41 */ 42 void * 43 vector_expand(void *buf, 44 size_t esize, size_t *ptr, size_t *len, size_t extra) 45 { 46 size_t nlen; 47 void *nbuf; 48 49 if (*len - *ptr >= extra) { 50 return buf; 51 } 52 nlen = (*len << 1); 53 if (nlen - *ptr < extra) { 54 nlen = extra + *ptr; 55 if (nlen < 8) { 56 nlen = 8; 57 } 58 } 59 nbuf = xmalloc(nlen * esize); 60 if (buf != NULL) { 61 memcpy(nbuf, buf, *len * esize); 62 xfree(buf); 63 } 64 *len = nlen; 65 return nbuf; 66 } 67