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asserters.go
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asserters.go
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package safecast
func assertNotNegative[T Type, T2 Type](i T, zero T2) error {
if i < 0 {
return Error{
err: ErrExceedMinimumValue,
value: i,
boundary: zero,
}
}
return nil
}
func checkUpperBoundary[T Type, T2 Type](value T, boundary T2) error {
if value <= 0 {
return nil
}
var greater bool
switch f := any(value).(type) {
case float64:
// for float64, everything fits in float64 without overflow.
// We are using a greater or equal because float cannot be compared easily because of precision loss.
greater = f >= float64(boundary)
case float32:
// everything fits in float32, except float64 greater than math.MaxFloat32.
// So, we must convert to float64 and check.
// We are using a greater or equal because float cannot be compared easily because of precision loss.
greater = float64(f) >= float64(boundary)
default:
// for all other integer types, it fits in an uint64 without overflow as we know value is positive.
greater = uint64(value) > uint64(boundary)
}
if greater {
return Error{
value: value,
boundary: boundary,
err: ErrExceedMaximumValue,
}
}
return nil
}
func checkLowerBoundary[T Type, T2 Type](value T, boundary T2) error {
if value >= 0 {
return nil
}
var smaller bool
switch f := any(value).(type) {
case float64:
// everything fits in float64 without overflow.
// We are using a lower or equal because float cannot be compared easily because of precision loss.
smaller = f <= float64(boundary)
case float32:
// everything fits in float32, except float64 smaller than -math.MaxFloat32.
// So, we must convert to float64 and check.
// We are using a lower or equal because float cannot be compared easily because of precision loss.
smaller = float64(f) <= float64(boundary)
default:
// for all other integer types, it fits in an int64 without overflow as we know value is negative.
smaller = int64(value) < int64(boundary)
}
if smaller {
return Error{
value: value,
boundary: boundary,
err: ErrExceedMinimumValue,
}
}
return nil
}