include/o3tl/safeint.hxx | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+)
New commits: commit 7b0bb820bb27d298eb4abec3ff4b09e7b6b299e7 Author: Caolán McNamara <[email protected]> Date: Wed Oct 25 09:44:59 2017 +0100 add checked_sub Change-Id: I440cd18c249f38194cfd3dfd4a1fc4b7f80858d6 Reviewed-on: https://gerrit.libreoffice.org/43810 Reviewed-by: Caolán McNamara <[email protected]> Tested-by: Caolán McNamara <[email protected]> diff --git a/include/o3tl/safeint.hxx b/include/o3tl/safeint.hxx index 1c8bf280171e..8b735fe2edfa 100644 --- a/include/o3tl/safeint.hxx +++ b/include/o3tl/safeint.hxx @@ -68,6 +68,11 @@ template<typename T> inline bool checked_add(T a, T b, T& result) return !msl::utilities::SafeAdd(a, b, result); } +template<typename T> inline bool checked_sub(T a, T b, T& result) +{ + return !msl::utilities::SafeSubtract(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) @@ -80,6 +85,11 @@ template<typename T> inline bool checked_add(T a, T b, T& result) return __builtin_add_overflow(a, b, &result); } +template<typename T> inline bool checked_sub(T a, T b, T& result) +{ + return __builtin_sub_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 @@ -149,6 +159,31 @@ template<typename T> inline typename std::enable_if<std::is_unsigned<T>::value, 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_sub(T a, T b, T& result) +{ + if ((b > 0 && a < std::numeric_limits<T>::min() + b) || + (b < 0 && a > std::numeric_limits<T>::max() + 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_sub(T a, T b, T& result) +{ + if (a < b) { + return true; + } + + result = a - b; + + return false; +} + #endif }
_______________________________________________ Libreoffice-commits mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/libreoffice-commits
