-
Notifications
You must be signed in to change notification settings - Fork 23
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
Showing
5 changed files
with
356 additions
and
34 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,221 @@ | ||
| #pragma once | ||
|
|
||
| #include <limits> | ||
| /** | ||
| * This type is designed to provide automatic checks for | ||
| * integer overflow and default initialization. It will | ||
| * throw an exception on overflow conditions. | ||
| * | ||
| * It can only be used on built-in types. In particular, | ||
| * safe<uint128_t> is buggy and should not be used. | ||
| * | ||
| * Implemented using spec from: | ||
| * https://www.securecoding.cert.org/confluence/display/c/INT32-C.+Ensure+that+operations+on+signed+integers+do+not+result+in+overflow | ||
| */ | ||
| template<typename T> | ||
| struct safe | ||
| { | ||
| T value = 0; | ||
|
|
||
| template<typename O> | ||
| safe( O o ):value(o){} | ||
| safe(){} | ||
| safe( const safe& o ):value(o.value){} | ||
|
|
||
| static safe min() | ||
| { | ||
| return std::numeric_limits<T>::min(); | ||
| } | ||
| static safe max() | ||
| { | ||
| return std::numeric_limits<T>::max(); | ||
| } | ||
|
|
||
| friend safe operator + ( const safe& a, const safe& b ) | ||
| { | ||
| if( b.value > 0 && a.value > (std::numeric_limits<T>::max() - b.value) ) check(false, "overflow_exception, (a)(b)" ); | ||
| if( b.value < 0 && a.value < (std::numeric_limits<T>::min() - b.value) ) check(false, "underflow_exception, (a)(b)" ); | ||
| return safe( a.value + b.value ); | ||
| } | ||
| friend safe operator - ( const safe& a, const safe& b ) | ||
| { | ||
| if( b.value > 0 && a.value < (std::numeric_limits<T>::min() + b.value) ) check(false, "underflow_exception, (a)(b)" ); | ||
| if( b.value < 0 && a.value > (std::numeric_limits<T>::max() + b.value) ) check(false, "overflow_exception, (a)(b)" ); | ||
| return safe( a.value - b.value ); | ||
| } | ||
|
|
||
| friend safe operator * ( const safe& a, const safe& b ) | ||
| { | ||
| if( a.value > 0 ) | ||
| { | ||
| if( b.value > 0 ) | ||
| { | ||
| if( a.value > (std::numeric_limits<T>::max() / b.value) ) check(false, "overflow_exception, (a)(b)" ); | ||
| } | ||
| else | ||
| { | ||
| if( b.value < (std::numeric_limits<T>::min() / a.value) ) check(false, "underflow_exception, (a)(b)" ); | ||
| } | ||
| } | ||
| else | ||
| { | ||
| if( b.value > 0 ) | ||
| { | ||
| if( a.value < (std::numeric_limits<T>::min() / b.value) ) check(false, "underflow_exception, (a)(b)" ); | ||
| } | ||
| else | ||
| { | ||
| if( a.value != 0 && b.value < (std::numeric_limits<T>::max() / a.value) ) check(false, "overflow_exception, (a)(b)" ); | ||
| } | ||
| } | ||
|
|
||
| return safe( a.value * b.value ); | ||
| } | ||
|
|
||
| friend safe operator / ( const safe& a, const safe& b ) | ||
| { | ||
| if( b.value == 0 ) check(false, "divide_by_zero_exception, (a)(b)" ); | ||
| if( a.value == std::numeric_limits<T>::min() && b.value == -1 ) check(false, "overflow_exception, (a)(b)" ); | ||
| return safe( a.value / b.value ); | ||
| } | ||
| friend safe operator % ( const safe& a, const safe& b ) | ||
| { | ||
| if( b.value == 0 ) check(false, "divide_by_zero_exception, (a)(b)" ); | ||
| if( a.value == std::numeric_limits<T>::min() && b.value == -1 ) check(false, "overflow_exception, (a)(b)" ); | ||
| return safe( a.value % b.value ); | ||
| } | ||
|
|
||
| safe operator - ()const | ||
| { | ||
| if( value == std::numeric_limits<T>::min() ) check(false, "overflow_exception, (*this)" ); | ||
| return safe( -value ); | ||
| } | ||
|
|
||
| safe& operator += ( const safe& b ) | ||
| { | ||
| value = (*this + b).value; | ||
| return *this; | ||
| } | ||
| safe& operator -= ( const safe& b ) | ||
| { | ||
| value = (*this - b).value; | ||
| return *this; | ||
| } | ||
| safe& operator *= ( const safe& b ) | ||
| { | ||
| value = (*this * b).value; | ||
| return *this; | ||
| } | ||
| safe& operator /= ( const safe& b ) | ||
| { | ||
| value = (*this / b).value; | ||
| return *this; | ||
| } | ||
| safe& operator %= ( const safe& b ) | ||
| { | ||
| value = (*this % b).value; | ||
| return *this; | ||
| } | ||
|
|
||
| safe& operator++() | ||
| { | ||
| *this += 1; | ||
| return *this; | ||
| } | ||
| safe operator++( int ) | ||
| { | ||
| safe bak = *this; | ||
| *this += 1; | ||
| return bak; | ||
| } | ||
|
|
||
| safe& operator--() | ||
| { | ||
| *this -= 1; | ||
| return *this; | ||
| } | ||
| safe operator--( int ) | ||
| { | ||
| safe bak = *this; | ||
| *this -= 1; | ||
| return bak; | ||
| } | ||
|
|
||
| friend bool operator == ( const safe& a, const safe& b ) | ||
| { | ||
| return a.value == b.value; | ||
| } | ||
| friend bool operator == ( const safe& a, const T& b ) | ||
| { | ||
| return a.value == b; | ||
| } | ||
| friend bool operator == ( const T& a, const safe& b ) | ||
| { | ||
| return a == b.value; | ||
| } | ||
|
|
||
| friend bool operator < ( const safe& a, const safe& b ) | ||
| { | ||
| return a.value < b.value; | ||
| } | ||
| friend bool operator < ( const safe& a, const T& b ) | ||
| { | ||
| return a.value < b; | ||
| } | ||
| friend bool operator < ( const T& a, const safe& b ) | ||
| { | ||
| return a < b.value; | ||
| } | ||
|
|
||
| friend bool operator > ( const safe& a, const safe& b ) | ||
| { | ||
| return a.value > b.value; | ||
| } | ||
| friend bool operator > ( const safe& a, const T& b ) | ||
| { | ||
| return a.value > b; | ||
| } | ||
| friend bool operator > ( const T& a, const safe& b ) | ||
| { | ||
| return a > b.value; | ||
| } | ||
|
|
||
| friend bool operator != ( const safe& a, const safe& b ) | ||
| { | ||
| return !(a == b); | ||
| } | ||
| friend bool operator != ( const safe& a, const T& b ) | ||
| { | ||
| return !(a == b); | ||
| } | ||
| friend bool operator != ( const T& a, const safe& b ) | ||
| { | ||
| return !(a == b); | ||
| } | ||
|
|
||
| friend bool operator <= ( const safe& a, const safe& b ) | ||
| { | ||
| return !(a > b); | ||
| } | ||
| friend bool operator <= ( const safe& a, const T& b ) | ||
| { | ||
| return !(a > b); | ||
| } | ||
| friend bool operator <= ( const T& a, const safe& b ) | ||
| { | ||
| return !(a > b); | ||
| } | ||
|
|
||
| friend bool operator >= ( const safe& a, const safe& b ) | ||
| { | ||
| return !(a < b); | ||
| } | ||
| friend bool operator >= ( const safe& a, const T& b ) | ||
| { | ||
| return !(a < b); | ||
| } | ||
| friend bool operator >= ( const T& a, const safe& b ) | ||
| { | ||
| return !(a < b); | ||
| } | ||
| }; |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.