std.overflow Package

Function Description

The overflow package provides the capability of processing overflows in integer operations.

In an integer operation, an overflow occurs if the operation result is greater than the maximum value of a type or less than the minimum value of a type. By default, an exception is thrown when an overflow occurs.

The overflow package provides four overflow processing policies and defines corresponding interfaces as follows:

Policy	Interface	Description
Returning Option	CheckedOp	When an overflow occurs in an integer operation, `None` is returned.
Saturating	SaturatingOp	If the operation result is greater than the MAX value of the target type, the MAX value is returned. If the operation result is less than the MIN value of the target type, the MIN value is returned.
Throwing exception	ThrowingOp	When an overflow occurs in an integer operation, an exception is thrown.
Most significant bit truncation	WrappingOp	When an overflow occurs in an integer operation, the most significant bits exceeding the number of bits of the target type in the operation result are truncated.

The overflow package implements these interfaces for all integer types through extension. Users can implement the overflow interfaces for other types in the same way.

API List

Interface

Name	Description
CheckedOp	Returns `None` when an overflow occurs in an integer operation.
SaturatingOp	Performs saturation processing when an overflow occurs in an integer operation.
ThrowingOp	Throws an exception when an overflow occurs in an integer operation.
WrappingOp	When an overflow occurs in an integer operation, the most significant bits exceeding the number of bits of the target type in the operation result are truncated.

Exception Class

Name	Description
OvershiftException	Specifies an exception thrown when the number of shifted bits exceeds the number of operand bits in a shift operation.
UndershiftException	Specifies an exception thrown when the number of shifted bits is less than 0 in a shift operation.