83 lines
1.8 KiB
Go
83 lines
1.8 KiB
Go
package cache
|
|
|
|
import (
|
|
"fmt"
|
|
"math"
|
|
)
|
|
|
|
func incr(originVal interface{}) (interface{}, error) {
|
|
switch val := originVal.(type) {
|
|
case int:
|
|
tmp := val + 1
|
|
if val > 0 && tmp < 0 {
|
|
return nil, fmt.Errorf("increment would overflow")
|
|
}
|
|
return tmp, nil
|
|
case int32:
|
|
if val == math.MaxInt32 {
|
|
return nil, fmt.Errorf("increment would overflow")
|
|
}
|
|
return val + 1, nil
|
|
case int64:
|
|
if val == math.MaxInt64 {
|
|
return nil, fmt.Errorf("increment would overflow")
|
|
}
|
|
return val + 1, nil
|
|
case uint:
|
|
tmp := val + 1
|
|
if tmp < val {
|
|
return nil, fmt.Errorf("increment would overflow")
|
|
}
|
|
return tmp, nil
|
|
case uint32:
|
|
if val == math.MaxUint32 {
|
|
return nil, fmt.Errorf("increment would overflow")
|
|
}
|
|
return val + 1, nil
|
|
case uint64:
|
|
if val == math.MaxUint64 {
|
|
return nil, fmt.Errorf("increment would overflow")
|
|
}
|
|
return val + 1, nil
|
|
default:
|
|
return nil, fmt.Errorf("item val is not (u)int (u)int32 (u)int64")
|
|
}
|
|
}
|
|
|
|
func decr(originVal interface{}) (interface{}, error) {
|
|
switch val := originVal.(type) {
|
|
case int:
|
|
tmp := val - 1
|
|
if val < 0 && tmp > 0 {
|
|
return nil, fmt.Errorf("decrement would overflow")
|
|
}
|
|
return tmp, nil
|
|
case int32:
|
|
if val == math.MinInt32 {
|
|
return nil, fmt.Errorf("decrement would overflow")
|
|
}
|
|
return val - 1, nil
|
|
case int64:
|
|
if val == math.MinInt64 {
|
|
return nil, fmt.Errorf("decrement would overflow")
|
|
}
|
|
return val - 1, nil
|
|
case uint:
|
|
if val == 0 {
|
|
return nil, fmt.Errorf("decrement would overflow")
|
|
}
|
|
return val - 1, nil
|
|
case uint32:
|
|
if val == 0 {
|
|
return nil, fmt.Errorf("increment would overflow")
|
|
}
|
|
return val - 1, nil
|
|
case uint64:
|
|
if val == 0 {
|
|
return nil, fmt.Errorf("increment would overflow")
|
|
}
|
|
return val - 1, nil
|
|
default:
|
|
return nil, fmt.Errorf("item val is not (u)int (u)int32 (u)int64")
|
|
}
|
|
} |