| /* |
| * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| #ifndef SIZECALC_H |
| #define SIZECALC_H |
| |
| /* |
| * A machinery for safe calculation of sizes used when allocating memory. |
| * |
| * All size checks are performed against the SIZE_MAX (the maximum value for |
| * size_t). All numerical arguments as well as the result of calculation must |
| * be non-negative integers less than or equal to SIZE_MAX, otherwise the |
| * calculated size is considered unsafe. |
| * |
| * If the SIZECALC_ALLOC_THROWING_BAD_ALLOC macro is defined, then _ALLOC_ |
| * helper macros throw the std::bad_alloc instead of returning NULL. |
| */ |
| |
| #include <stdint.h> /* SIZE_MAX for C99+ */ |
| /* http://stackoverflow.com/questions/3472311/what-is-a-portable-method-to-find-the-maximum-value-of-size-t */ |
| #ifndef SIZE_MAX |
| #define SIZE_MAX ((size_t)-1) |
| #endif |
| |
| #define IS_SAFE_SIZE_T(x) ((x) >= 0 && (unsigned long long)(x) <= SIZE_MAX) |
| |
| #define IS_SAFE_SIZE_MUL(m, n) \ |
| (IS_SAFE_SIZE_T(m) && IS_SAFE_SIZE_T(n) && ((m) == 0 || (n) == 0 || (size_t)(n) <= (SIZE_MAX / (size_t)(m)))) |
| |
| #define IS_SAFE_SIZE_ADD(a, b) \ |
| (IS_SAFE_SIZE_T(a) && IS_SAFE_SIZE_T(b) && (size_t)(b) <= (SIZE_MAX - (size_t)(a))) |
| |
| |
| |
| /* Helper macros */ |
| |
| #ifdef SIZECALC_ALLOC_THROWING_BAD_ALLOC |
| #define FAILURE_RESULT throw std::bad_alloc() |
| #else |
| #define FAILURE_RESULT NULL |
| #endif |
| |
| /* |
| * A helper macro to safely allocate an array of size m*n. |
| * Example usage: |
| * int* p = (int*)SAFE_SIZE_ARRAY_ALLOC(malloc, sizeof(int), n); |
| * if (!p) throw OutOfMemory; |
| * // Use the allocated array... |
| */ |
| #define SAFE_SIZE_ARRAY_ALLOC(func, m, n) \ |
| (IS_SAFE_SIZE_MUL((m), (n)) ? ((func)((m) * (n))) : FAILURE_RESULT) |
| |
| #define SAFE_SIZE_ARRAY_REALLOC(func, p, m, n) \ |
| (IS_SAFE_SIZE_MUL((m), (n)) ? ((func)((p), (m) * (n))) : FAILURE_RESULT) |
| |
| /* |
| * A helper macro to safely allocate an array of type 'type' with 'n' items |
| * using the C++ new[] operator. |
| * Example usage: |
| * MyClass* p = SAFE_SIZE_NEW_ARRAY(MyClass, n); |
| * // Use the pointer. |
| * This macro throws the std::bad_alloc C++ exception to indicate |
| * a failure. |
| * NOTE: if 'n' is calculated, the calling code is responsible for using the |
| * IS_SAFE_... macros to check if the calculations are safe. |
| */ |
| #define SAFE_SIZE_NEW_ARRAY(type, n) \ |
| (IS_SAFE_SIZE_MUL(sizeof(type), (n)) ? (new type[(n)]) : throw std::bad_alloc()) |
| |
| #define SAFE_SIZE_NEW_ARRAY2(type, n, m) \ |
| (IS_SAFE_SIZE_MUL((m), (n)) && IS_SAFE_SIZE_MUL(sizeof(type), (n) * (m)) ? \ |
| (new type[(n) * (m)]) : throw std::bad_alloc()) |
| |
| /* |
| * Checks if a data structure of size (a + m*n) can be safely allocated |
| * w/o producing an integer overflow when calculating its size. |
| */ |
| #define IS_SAFE_STRUCT_SIZE(a, m, n) \ |
| ( \ |
| IS_SAFE_SIZE_MUL((m), (n)) && IS_SAFE_SIZE_ADD((m) * (n), (a)) \ |
| ) |
| |
| /* |
| * A helper macro for implementing safe memory allocation for a data structure |
| * of size (a + m * n). |
| * Example usage: |
| * void * p = SAFE_SIZE_ALLOC(malloc, header, num, itemSize); |
| * if (!p) throw OutOfMemory; |
| * // Use the allocated memory... |
| */ |
| #define SAFE_SIZE_STRUCT_ALLOC(func, a, m, n) \ |
| (IS_SAFE_STRUCT_SIZE((a), (m), (n)) ? ((func)((a) + (m) * (n))) : FAILURE_RESULT) |
| |
| |
| #endif /* SIZECALC_H */ |
| |