typeConver.go

package validate

import (
	"encoding/binary"
	"encoding/json"
	"fmt"
	"math"
	"reflect"
	"strconv"
	"time"
)

func String(i interface{}) string {
	if i == nil {
		return ""
	}
	switch value := i.(type) {
	case int:
		return strconv.Itoa(value)
	case int8:
		return strconv.Itoa(int(value))
	case int16:
		return strconv.Itoa(int(value))
	case int32:
		return strconv.Itoa(int(value))
	case int64:
		return strconv.FormatInt(value, 10)
	case uint:
		return strconv.FormatUint(uint64(value), 10)
	case uint8:
		return strconv.FormatUint(uint64(value), 10)
	case uint16:
		return strconv.FormatUint(uint64(value), 10)
	case uint32:
		return strconv.FormatUint(uint64(value), 10)
	case uint64:
		return strconv.FormatUint(value, 10)
	case float32:
		return strconv.FormatFloat(float64(value), 'f', -1, 32)
	case float64:
		return strconv.FormatFloat(value, 'f', -1, 64)
	case bool:
		return strconv.FormatBool(value)
	case string:
		return value
	case []byte:
		return string(value)
	case time.Time:
		if value.IsZero() {
			return ""
		}
		return value.String()
	case *time.Time:
		if value == nil {
			return ""
		}
		return value.String()
	default:
		if value == nil {
			return ""
		}
		rv := reflect.ValueOf(value)
		kind := rv.Kind()
		switch kind {
		case reflect.Chan,
			reflect.Map,
			reflect.Slice,
			reflect.Func,
			reflect.Ptr,
			reflect.Interface,
			reflect.UnsafePointer:
			if rv.IsNil() {
				return ""
			}
		}
		if kind == reflect.Ptr {
			return String(rv.Elem().Interface())
		}

		if jsonContent, err := json.Marshal(value); err != nil {
			return fmt.Sprint(value)
		} else {
			return string(jsonContent)
		}
	}
}

func Float64(i interface{}) float64 {
	if i == nil {
		return 0
	}
	switch value := i.(type) {
	case float32:
		return float64(value)
	case float64:
		return value
	case []byte:
		return LeDecodeToFloat64(value)
	default:
		v, _ := strconv.ParseFloat(String(i), 64)
		return v
	}
}

func Int(i interface{}) int {
	if i == nil {
		return 0
	}
	if v, ok := i.(int); ok {
		return v
	}
	return int(Int64(i))
}

func Int64(i interface{}) int64 {
	if i == nil {
		return 0
	}
	switch value := i.(type) {
	case int:
		return int64(value)
	case int8:
		return int64(value)
	case int16:
		return int64(value)
	case int32:
		return int64(value)
	case int64:
		return value
	case uint:
		return int64(value)
	case uint8:
		return int64(value)
	case uint16:
		return int64(value)
	case uint32:
		return int64(value)
	case uint64:
		return int64(value)
	case float32:
		return int64(value)
	case float64:
		return int64(value)
	case bool:
		if value {
			return 1
		}
		return 0
	case []byte:
		return LeDecodeToInt64(value)
	default:
		s := String(value)
		isMinus := false
		if len(s) > 0 {
			if s[0] == '-' {
				isMinus = true
				s = s[1:]
			} else if s[0] == '+' {
				s = s[1:]
			}
		}
		// Hexadecimal
		if len(s) > 2 && s[0] == '0' && (s[1] == 'x' || s[1] == 'X') {
			if v, e := strconv.ParseInt(s[2:], 16, 64); e == nil {
				if isMinus {
					return -v
				}
				return v
			}
		}
		// Octal
		if len(s) > 1 && s[0] == '0' {
			if v, e := strconv.ParseInt(s[1:], 8, 64); e == nil {
				if isMinus {
					return -v
				}
				return v
			}
		}
		// Decimal
		if v, e := strconv.ParseInt(s, 10, 64); e == nil {
			if isMinus {
				return -v
			}
			return v
		}
		// Float64
		return int64(Float64(value))
	}
}

func Uint64(i interface{}) uint64 {
	if i == nil {
		return 0
	}
	switch value := i.(type) {
	case int:
		return uint64(value)
	case int8:
		return uint64(value)
	case int16:
		return uint64(value)
	case int32:
		return uint64(value)
	case int64:
		return uint64(value)
	case uint:
		return uint64(value)
	case uint8:
		return uint64(value)
	case uint16:
		return uint64(value)
	case uint32:
		return uint64(value)
	case uint64:
		return value
	case float32:
		return uint64(value)
	case float64:
		return uint64(value)
	case bool:
		if value {
			return 1
		}
		return 0
	case []byte:
		return LeDecodeToUint64(value)
	default:
		s := String(value)
		// Hexadecimal
		if len(s) > 2 && s[0] == '0' && (s[1] == 'x' || s[1] == 'X') {
			if v, e := strconv.ParseUint(s[2:], 16, 64); e == nil {
				return v
			}
		}
		// Octal
		if len(s) > 1 && s[0] == '0' {
			if v, e := strconv.ParseUint(s[1:], 8, 64); e == nil {
				return v
			}
		}
		// Decimal
		if v, e := strconv.ParseUint(s, 10, 64); e == nil {
			return v
		}
		// Float64
		return uint64(Float64(value))
	}
}

func LeDecodeToUint64(b []byte) uint64 {
	return binary.LittleEndian.Uint64(LeFillUpSize(b, 8))
}

func LeDecodeToInt64(b []byte) int64 {
	return int64(binary.LittleEndian.Uint64(LeFillUpSize(b, 8)))
}

func LeDecodeToFloat64(b []byte) float64 {
	return math.Float64frombits(binary.LittleEndian.Uint64(LeFillUpSize(b, 8)))
}

func LeFillUpSize(b []byte, l int) []byte {
	if len(b) >= l {
		return b[:l]
	}
	c := make([]byte, l)
	copy(c, b)
	return c
}