Arithmetic operations with overflow checks. More...
#include <type_traits>
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Functions | |
| template<typename T1 , typename T2 , typename R > | |
| std::enable_if< std::is_unsigned< T1 >::value &&std::is_unsigned< T2 >::value &&std::is_unsigned< R >::value, bool >::type | add_overflows (T1 a, T2 b, R &res) |
| Addition with overflow checking. More... | |
| template<typename T1 , typename T2 , typename R > | |
| std::enable_if< std::is_unsigned< T1 >::value &&std::is_unsigned< T2 >::value &&std::is_unsigned< R >::value, bool >::type | sub_overflows (T1 a, T2 b, R &res) |
| Subtraction with overflow checking. More... | |
| template<typename T1 , typename T2 , typename R > | |
| std::enable_if< std::is_unsigned< T1 >::value &&std::is_unsigned< T2 >::value &&std::is_unsigned< R >::value, bool >::type | mul_overflows (T1 a, T2 b, R &res) |
| Multiplication with overflow checking. More... | |
Detailed Description
Arithmetic operations with overflow checks.
The operations are implemented with compiler builtins or equivalent where possible, so the overflow check will typically just require a check of the processor's overflow or carry flag.
Definition in file overflow.h.
Function Documentation
◆ add_overflows()
| std::enable_if<std::is_unsigned<T1>::value && std::is_unsigned<T2>::value && std::is_unsigned<R>::value, bool>::type add_overflows | ( | T1 | a, |
| T2 | b, | ||
| R & | res | ||
| ) |
Addition with overflow checking.
Add a and b in infinite precision, and store the result in res.
Where possible, compiler built-ins or intrinsics are used to try to ensure minimal overhead from the overflow check.
Currently only supported when types involved are unsigned.
- Returns
- true if the result can be represented exactly in res, false otherwise.
Definition at line 58 of file overflow.h.
Referenced by parse_unsigned(), test_addoverflows1(), and throw_timeout().
◆ mul_overflows()
| std::enable_if<std::is_unsigned<T1>::value && std::is_unsigned<T2>::value && std::is_unsigned<R>::value, bool>::type mul_overflows | ( | T1 | a, |
| T2 | b, | ||
| R & | res | ||
| ) |
Multiplication with overflow checking.
Multiply a and b in infinite precision, and store the result in res.
Where possible, compiler built-ins or intrinsics are used to try to ensure minimal overhead from the overflow check.
Currently only supported when types involved are unsigned.
- Returns
- true if the result can be represented exactly in res, false otherwise.
Definition at line 188 of file overflow.h.
Referenced by parse_unsigned(), Xapian::Document::Internal::remove_postings(), and test_muloverflows1().
◆ sub_overflows()
| std::enable_if<std::is_unsigned<T1>::value && std::is_unsigned<T2>::value && std::is_unsigned<R>::value, bool>::type sub_overflows | ( | T1 | a, |
| T2 | b, | ||
| R & | res | ||
| ) |
Subtraction with overflow checking.
Subtract b from a in infinite precision, and store the result in res.
Where possible, compiler built-ins or intrinsics are used to try to ensure minimal overhead from the overflow check.
Currently only supported when types involved are unsigned.
- Returns
- true if the result can be represented exactly in res, false otherwise.
Definition at line 125 of file overflow.h.
Referenced by test_suboverflows1().