1 /* 2 * Copyright (c) 2014-2017 Pavel Kalvoda <me@pavelkalvoda.com> 3 * 4 * libcbor is free software; you can redistribute it and/or modify 5 * it under the terms of the MIT license. See LICENSE for details. 6 */ 7 8 #include "memory_utils.h" 9 #include "cbor/common.h" 10 11 // TODO: Consider builtins (https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html) 12 13 /** Highest on bit position */ 14 size_t _cbor_highest_bit(size_t number) 15 { 16 size_t bit = 0; 17 while (number != 0) { 18 bit++; 19 number >>= 1; 20 } 21 22 return bit; 23 } 24 25 bool _cbor_safe_to_multiply(size_t a, size_t b) 26 { 27 return _cbor_highest_bit(a) + _cbor_highest_bit(b) <= sizeof(size_t) * 8; 28 } 29 30 void * _cbor_alloc_multiple(size_t item_size, size_t item_count) 31 { 32 if (_cbor_safe_to_multiply(item_size, item_count)) { 33 return _CBOR_MALLOC(item_size * item_count); 34 } else { 35 return NULL; 36 } 37 } 38 39 void * _cbor_realloc_multiple(void * pointer, size_t item_size, size_t item_count) 40 { 41 if (_cbor_safe_to_multiply(item_size, item_count)) { 42 return _CBOR_REALLOC(pointer, item_size * item_count); 43 } else { 44 return NULL; 45 } 46 } 47