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caste.go
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caste.go
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// Copyright © 2014 Steve Francia <spf@spf13.com>.
//
// Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file.
package cast
import (
"encoding/json"
"errors"
"fmt"
"html/template"
"reflect"
"strconv"
"strings"
"time"
)
var errNegativeNotAllowed = errors.New("unable to cast negative value")
// ToTimeE casts an interface to a time.Time type.
func ToTimeE(i interface{}) (tim time.Time, err error) {
return ToTimeInDefaultLocationE(i, time.UTC)
}
// ToTimeInDefaultLocationE casts an empty interface to time.Time,
// interpreting inputs without a timezone to be in the given location,
// or the local timezone if nil.
func ToTimeInDefaultLocationE(i interface{}, location *time.Location) (tim time.Time, err error) {
i = indirect(i)
switch v := i.(type) {
case time.Time:
return v, nil
case string:
return StringToDateInDefaultLocation(v, location)
case json.Number:
s, err1 := ToInt64E(v)
if err1 != nil {
return time.Time{}, fmt.Errorf("unable to cast %#v of type %T to Time", i, i)
}
return time.Unix(s, 0), nil
case int:
return time.Unix(int64(v), 0), nil
case int64:
return time.Unix(v, 0), nil
case int32:
return time.Unix(int64(v), 0), nil
case uint:
return time.Unix(int64(v), 0), nil
case uint64:
return time.Unix(int64(v), 0), nil
case uint32:
return time.Unix(int64(v), 0), nil
default:
return time.Time{}, fmt.Errorf("unable to cast %#v of type %T to Time", i, i)
}
}
// ToDurationE casts an interface to a time.Duration type.
func ToDurationE(i interface{}) (d time.Duration, err error) {
i = indirect(i)
switch s := i.(type) {
case time.Duration:
return s, nil
case int, int64, int32, int16, int8, uint, uint64, uint32, uint16, uint8:
d = time.Duration(ToInt64(s))
return
case float32, float64:
d = time.Duration(ToFloat64(s))
return
case string:
if strings.ContainsAny(s, "nsuµmh") {
d, err = time.ParseDuration(s)
} else {
d, err = time.ParseDuration(s + "ns")
}
return
case json.Number:
var v float64
v, err = s.Float64()
d = time.Duration(v)
return
default:
err = fmt.Errorf("unable to cast %#v of type %T to Duration", i, i)
return
}
}
// ToBoolE casts an interface to a bool type.
func ToBoolE(i interface{}) (bool, error) {
i = indirect(i)
switch b := i.(type) {
case bool:
return b, nil
case nil:
return false, nil
case int:
return b != 0, nil
case int64:
return b != 0, nil
case int32:
return b != 0, nil
case int16:
return b != 0, nil
case int8:
return b != 0, nil
case uint:
return b != 0, nil
case uint64:
return b != 0, nil
case uint32:
return b != 0, nil
case uint16:
return b != 0, nil
case uint8:
return b != 0, nil
case float64:
return b != 0, nil
case float32:
return b != 0, nil
case time.Duration:
return b != 0, nil
case string:
return strconv.ParseBool(i.(string))
case json.Number:
v, err := ToInt64E(b)
if err == nil {
return v != 0, nil
}
return false, fmt.Errorf("unable to cast %#v of type %T to bool", i, i)
default:
return false, fmt.Errorf("unable to cast %#v of type %T to bool", i, i)
}
}
// ToFloat64E casts an interface to a float64 type.
func ToFloat64E(i interface{}) (float64, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
return float64(intv), nil
}
switch s := i.(type) {
case float64:
return s, nil
case float32:
return float64(s), nil
case int64:
return float64(s), nil
case int32:
return float64(s), nil
case int16:
return float64(s), nil
case int8:
return float64(s), nil
case uint:
return float64(s), nil
case uint64:
return float64(s), nil
case uint32:
return float64(s), nil
case uint16:
return float64(s), nil
case uint8:
return float64(s), nil
case string:
v, err := strconv.ParseFloat(s, 64)
if err == nil {
return v, nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to float64", i, i)
case json.Number:
v, err := s.Float64()
if err == nil {
return v, nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to float64", i, i)
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to float64", i, i)
}
}
// ToFloat32E casts an interface to a float32 type.
func ToFloat32E(i interface{}) (float32, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
return float32(intv), nil
}
switch s := i.(type) {
case float64:
return float32(s), nil
case float32:
return s, nil
case int64:
return float32(s), nil
case int32:
return float32(s), nil
case int16:
return float32(s), nil
case int8:
return float32(s), nil
case uint:
return float32(s), nil
case uint64:
return float32(s), nil
case uint32:
return float32(s), nil
case uint16:
return float32(s), nil
case uint8:
return float32(s), nil
case string:
v, err := strconv.ParseFloat(s, 32)
if err == nil {
return float32(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to float32", i, i)
case json.Number:
v, err := s.Float64()
if err == nil {
return float32(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to float32", i, i)
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to float32", i, i)
}
}
// ToInt64E casts an interface to an int64 type.
func ToInt64E(i interface{}) (int64, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
return int64(intv), nil
}
switch s := i.(type) {
case int64:
return s, nil
case int32:
return int64(s), nil
case int16:
return int64(s), nil
case int8:
return int64(s), nil
case uint:
return int64(s), nil
case uint64:
return int64(s), nil
case uint32:
return int64(s), nil
case uint16:
return int64(s), nil
case uint8:
return int64(s), nil
case float64:
return int64(s), nil
case float32:
return int64(s), nil
case string:
v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
if err == nil {
return v, nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to int64", i, i)
case json.Number:
return ToInt64E(string(s))
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to int64", i, i)
}
}
// ToInt32E casts an interface to an int32 type.
func ToInt32E(i interface{}) (int32, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
return int32(intv), nil
}
switch s := i.(type) {
case int64:
return int32(s), nil
case int32:
return s, nil
case int16:
return int32(s), nil
case int8:
return int32(s), nil
case uint:
return int32(s), nil
case uint64:
return int32(s), nil
case uint32:
return int32(s), nil
case uint16:
return int32(s), nil
case uint8:
return int32(s), nil
case float64:
return int32(s), nil
case float32:
return int32(s), nil
case string:
v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
if err == nil {
return int32(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to int32", i, i)
case json.Number:
return ToInt32E(string(s))
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to int32", i, i)
}
}
// ToInt16E casts an interface to an int16 type.
func ToInt16E(i interface{}) (int16, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
return int16(intv), nil
}
switch s := i.(type) {
case int64:
return int16(s), nil
case int32:
return int16(s), nil
case int16:
return s, nil
case int8:
return int16(s), nil
case uint:
return int16(s), nil
case uint64:
return int16(s), nil
case uint32:
return int16(s), nil
case uint16:
return int16(s), nil
case uint8:
return int16(s), nil
case float64:
return int16(s), nil
case float32:
return int16(s), nil
case string:
v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
if err == nil {
return int16(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to int16", i, i)
case json.Number:
return ToInt16E(string(s))
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to int16", i, i)
}
}
// ToInt8E casts an interface to an int8 type.
func ToInt8E(i interface{}) (int8, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
return int8(intv), nil
}
switch s := i.(type) {
case int64:
return int8(s), nil
case int32:
return int8(s), nil
case int16:
return int8(s), nil
case int8:
return s, nil
case uint:
return int8(s), nil
case uint64:
return int8(s), nil
case uint32:
return int8(s), nil
case uint16:
return int8(s), nil
case uint8:
return int8(s), nil
case float64:
return int8(s), nil
case float32:
return int8(s), nil
case string:
v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
if err == nil {
return int8(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to int8", i, i)
case json.Number:
return ToInt8E(string(s))
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to int8", i, i)
}
}
// ToIntE casts an interface to an int type.
func ToIntE(i interface{}) (int, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
return intv, nil
}
switch s := i.(type) {
case int64:
return int(s), nil
case int32:
return int(s), nil
case int16:
return int(s), nil
case int8:
return int(s), nil
case uint:
return int(s), nil
case uint64:
return int(s), nil
case uint32:
return int(s), nil
case uint16:
return int(s), nil
case uint8:
return int(s), nil
case float64:
return int(s), nil
case float32:
return int(s), nil
case string:
v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
if err == nil {
return int(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to int64", i, i)
case json.Number:
return ToIntE(string(s))
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to int", i, i)
}
}
// ToUintE casts an interface to a uint type.
func ToUintE(i interface{}) (uint, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
if intv < 0 {
return 0, errNegativeNotAllowed
}
return uint(intv), nil
}
switch s := i.(type) {
case string:
v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
if err == nil {
if v < 0 {
return 0, errNegativeNotAllowed
}
return uint(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to uint", i, i)
case json.Number:
return ToUintE(string(s))
case int64:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint(s), nil
case int32:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint(s), nil
case int16:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint(s), nil
case int8:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint(s), nil
case uint:
return s, nil
case uint64:
return uint(s), nil
case uint32:
return uint(s), nil
case uint16:
return uint(s), nil
case uint8:
return uint(s), nil
case float64:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint(s), nil
case float32:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint(s), nil
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to uint", i, i)
}
}
// ToUint64E casts an interface to a uint64 type.
func ToUint64E(i interface{}) (uint64, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
if intv < 0 {
return 0, errNegativeNotAllowed
}
return uint64(intv), nil
}
switch s := i.(type) {
case string:
v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
if err == nil {
if v < 0 {
return 0, errNegativeNotAllowed
}
return uint64(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to uint64", i, i)
case json.Number:
return ToUint64E(string(s))
case int64:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint64(s), nil
case int32:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint64(s), nil
case int16:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint64(s), nil
case int8:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint64(s), nil
case uint:
return uint64(s), nil
case uint64:
return s, nil
case uint32:
return uint64(s), nil
case uint16:
return uint64(s), nil
case uint8:
return uint64(s), nil
case float32:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint64(s), nil
case float64:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint64(s), nil
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to uint64", i, i)
}
}
// ToUint32E casts an interface to a uint32 type.
func ToUint32E(i interface{}) (uint32, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
if intv < 0 {
return 0, errNegativeNotAllowed
}
return uint32(intv), nil
}
switch s := i.(type) {
case string:
v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
if err == nil {
if v < 0 {
return 0, errNegativeNotAllowed
}
return uint32(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to uint32", i, i)
case json.Number:
return ToUint32E(string(s))
case int64:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint32(s), nil
case int32:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint32(s), nil
case int16:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint32(s), nil
case int8:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint32(s), nil
case uint:
return uint32(s), nil
case uint64:
return uint32(s), nil
case uint32:
return s, nil
case uint16:
return uint32(s), nil
case uint8:
return uint32(s), nil
case float64:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint32(s), nil
case float32:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint32(s), nil
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to uint32", i, i)
}
}
// ToUint16E casts an interface to a uint16 type.
func ToUint16E(i interface{}) (uint16, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
if intv < 0 {
return 0, errNegativeNotAllowed
}
return uint16(intv), nil
}
switch s := i.(type) {
case string:
v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
if err == nil {
if v < 0 {
return 0, errNegativeNotAllowed
}
return uint16(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to uint16", i, i)
case json.Number:
return ToUint16E(string(s))
case int64:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint16(s), nil
case int32:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint16(s), nil
case int16:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint16(s), nil
case int8:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint16(s), nil
case uint:
return uint16(s), nil
case uint64:
return uint16(s), nil
case uint32:
return uint16(s), nil
case uint16:
return s, nil
case uint8:
return uint16(s), nil
case float64:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint16(s), nil
case float32:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint16(s), nil
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to uint16", i, i)
}
}
// ToUint8E casts an interface to a uint type.
func ToUint8E(i interface{}) (uint8, error) {
i = indirect(i)
intv, ok := toInt(i)
if ok {
if intv < 0 {
return 0, errNegativeNotAllowed
}
return uint8(intv), nil
}
switch s := i.(type) {
case string:
v, err := strconv.ParseInt(trimZeroDecimal(s), 0, 0)
if err == nil {
if v < 0 {
return 0, errNegativeNotAllowed
}
return uint8(v), nil
}
return 0, fmt.Errorf("unable to cast %#v of type %T to uint8", i, i)
case json.Number:
return ToUint8E(string(s))
case int64:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint8(s), nil
case int32:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint8(s), nil
case int16:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint8(s), nil
case int8:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint8(s), nil
case uint:
return uint8(s), nil
case uint64:
return uint8(s), nil
case uint32:
return uint8(s), nil
case uint16:
return uint8(s), nil
case uint8:
return s, nil
case float64:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint8(s), nil
case float32:
if s < 0 {
return 0, errNegativeNotAllowed
}
return uint8(s), nil
case bool:
if s {
return 1, nil
}
return 0, nil
case nil:
return 0, nil
default:
return 0, fmt.Errorf("unable to cast %#v of type %T to uint8", i, i)
}
}
// From html/template/content.go
// Copyright 2011 The Go Authors. All rights reserved.
// indirect returns the value, after dereferencing as many times
// as necessary to reach the base type (or nil).
func indirect(a interface{}) interface{} {
if a == nil {
return nil
}
if t := reflect.TypeOf(a); t.Kind() != reflect.Ptr {
// Avoid creating a reflect.Value if it's not a pointer.
return a
}
v := reflect.ValueOf(a)
for v.Kind() == reflect.Ptr && !v.IsNil() {
v = v.Elem()
}
return v.Interface()
}
// From html/template/content.go
// Copyright 2011 The Go Authors. All rights reserved.
// indirectToStringerOrError returns the value, after dereferencing as many times
// as necessary to reach the base type (or nil) or an implementation of fmt.Stringer
// or error,
func indirectToStringerOrError(a interface{}) interface{} {
if a == nil {
return nil
}
var errorType = reflect.TypeOf((*error)(nil)).Elem()
var fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
v := reflect.ValueOf(a)
for !v.Type().Implements(fmtStringerType) && !v.Type().Implements(errorType) && v.Kind() == reflect.Ptr && !v.IsNil() {
v = v.Elem()
}
return v.Interface()
}
// ToStringE casts an interface to a string type.
func ToStringE(i interface{}) (string, error) {
i = indirectToStringerOrError(i)
switch s := i.(type) {
case string:
return s, nil
case bool:
return strconv.FormatBool(s), nil
case float64:
return strconv.FormatFloat(s, 'f', -1, 64), nil
case float32:
return strconv.FormatFloat(float64(s), 'f', -1, 32), nil
case int:
return strconv.Itoa(s), nil
case int64:
return strconv.FormatInt(s, 10), nil
case int32:
return strconv.Itoa(int(s)), nil
case int16:
return strconv.FormatInt(int64(s), 10), nil
case int8:
return strconv.FormatInt(int64(s), 10), nil
case uint:
return strconv.FormatUint(uint64(s), 10), nil
case uint64:
return strconv.FormatUint(uint64(s), 10), nil
case uint32:
return strconv.FormatUint(uint64(s), 10), nil
case uint16:
return strconv.FormatUint(uint64(s), 10), nil
case uint8:
return strconv.FormatUint(uint64(s), 10), nil
case json.Number:
return s.String(), nil
case []byte:
return string(s), nil
case template.HTML:
return string(s), nil
case template.URL:
return string(s), nil
case template.JS:
return string(s), nil
case template.CSS:
return string(s), nil
case template.HTMLAttr:
return string(s), nil
case nil:
return "", nil
case fmt.Stringer:
return s.String(), nil
case error:
return s.Error(), nil
default:
return "", fmt.Errorf("unable to cast %#v of type %T to string", i, i)
}
}
// ToStringMapStringE casts an interface to a map[string]string type.
func ToStringMapStringE(i interface{}) (map[string]string, error) {
var m = map[string]string{}
switch v := i.(type) {
case map[string]string:
return v, nil
case map[string]interface{}:
for k, val := range v {
m[ToString(k)] = ToString(val)
}
return m, nil
case map[interface{}]string: