diff options
Diffstat (limited to 'include/o3tl')
-rw-r--r-- | include/o3tl/safeint.hxx | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/include/o3tl/safeint.hxx b/include/o3tl/safeint.hxx new file mode 100644 index 000000000000..5ebf353b6bd6 --- /dev/null +++ b/include/o3tl/safeint.hxx @@ -0,0 +1,124 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#ifndef INCLUDED_O3TL_SAFEINT_HXX +#define INCLUDED_O3TL_SAFEINT_HXX + +#include <limits> +#if defined(_MSC_VER) +#include <safeint.h> +#else +#ifndef __has_builtin +# define __has_builtin(x) 0 +#endif +#endif + +namespace o3tl +{ + +#if defined(_MSC_VER) + +template<typename T> inline bool checked_multiply(T a, T b, T& result) +{ + return !msl::utilities::SafeMultiply(a, b, result); +} + +template<typename T> inline bool checked_add(T a, T b, T& result) +{ + return !msl::utilities::SafeAdd(a, b, result); +} + +#elif (defined __GNUC__ && __GNUC__ >= 5) || (__has_builtin(__builtin_mul_overflow) && !(defined ANDROID && defined __clang__)) + +template<typename T> inline bool checked_multiply(T a, T b, T& result) +{ + return __builtin_mul_overflow(a, b, &result); +} + +template<typename T> inline bool checked_add(T a, T b, T& result) +{ + return __builtin_add_overflow(a, b, &result); +} + +#else + +//https://www.securecoding.cert.org/confluence/display/c/INT32-C.+Ensure+that+operations+on+signed+integers+do+not+result+in+overflow +template<typename T> inline typename std::enable_if<std::is_signed<T>::value, bool>::type checked_multiply(T a, T b, T& result) +{ + if (a > 0) { /* a is positive */ + if (b > 0) { /* a and b are positive */ + if (a > (std::numeric_limits<T>::max() / b)) { + return true; /* Handle error */ + } + } else { /* a positive, b nonpositive */ + if (b < (std::numeric_limits<T>::min() / a)) { + return true; /* Handle error */ + } + } /* a positive, b nonpositive */ + } else { /* a is nonpositive */ + if (b > 0) { /* a is nonpositive, b is positive */ + if (a < (std::numeric_limits<T>::min() / b)) { + return true; /* Handle error */ + } + } else { /* a and b are nonpositive */ + if ( (a != 0) && (b < (std::numeric_limits<T>::max() / a))) { + return true; /* Handle error */ + } + } /* End if a and b are nonpositive */ + } /* End if a is nonpositive */ + + result = a * b; + + return false; +} + +//https://www.securecoding.cert.org/confluence/display/c/INT30-C.+Ensure+that+unsigned+integer+operations+do+not+wrap +template<typename T> inline typename std::enable_if<std::is_unsigned<T>::value, bool>::type checked_multiply(T a, T b, T& result) +{ + if (b && a > std::numeric_limits<T>::max() / b) { + return true;/* Handle error */ + } + + result = a * b; + + return false; +} + +//https://www.securecoding.cert.org/confluence/display/c/INT32-C.+Ensure+that+operations+on+signed+integers+do+not+result+in+overflow +template<typename T> inline typename std::enable_if<std::is_signed<T>::value, bool>::type checked_add(T a, T b, T& result) +{ + if (((b > 0) && (a > (std::numeric_limits<T>::max() - b))) || + ((b < 0) && (a < (std::numeric_limits<T>::min() - b)))) { + return true; + } + + result = a + b; + + return false; +} + +//https://www.securecoding.cert.org/confluence/display/c/INT30-C.+Ensure+that+unsigned+integer+operations+do+not+wrap +template<typename T> inline typename std::enable_if<std::is_unsigned<T>::value, bool>::type checked_add(T a, T b, T& result) +{ + if (std::numeric_limits<T>::max() - a < b) { + return true;/* Handle error */ + } + + result = a + b; + + return false; +} + +#endif + +} + +#endif + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |