forked from mirror/go-json
439 lines
12 KiB
Go
439 lines
12 KiB
Go
package decoder
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import (
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"fmt"
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"reflect"
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"strconv"
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)
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var (
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nilValue = reflect.ValueOf(nil)
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)
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func AssignValue(src, dst reflect.Value) error {
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if dst.Type().Kind() != reflect.Ptr {
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return fmt.Errorf("invalid dst type. required pointer type: %T", dst.Type())
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}
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casted, err := castValue(dst.Elem().Type(), src)
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if err != nil {
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return err
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}
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dst.Elem().Set(casted)
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return nil
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}
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func castValue(t reflect.Type, v reflect.Value) (reflect.Value, error) {
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switch t.Kind() {
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case reflect.Int:
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vv, err := castInt(v)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(int(vv.Int())), nil
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case reflect.Int8:
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vv, err := castInt(v)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(int8(vv.Int())), nil
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case reflect.Int16:
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vv, err := castInt(v)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(int16(vv.Int())), nil
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case reflect.Int32:
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vv, err := castInt(v)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(int32(vv.Int())), nil
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case reflect.Int64:
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return castInt(v)
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case reflect.Uint:
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vv, err := castUint(v)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(uint(vv.Uint())), nil
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case reflect.Uint8:
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vv, err := castUint(v)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(uint8(vv.Uint())), nil
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case reflect.Uint16:
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vv, err := castUint(v)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(uint16(vv.Uint())), nil
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case reflect.Uint32:
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vv, err := castUint(v)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(uint32(vv.Uint())), nil
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case reflect.Uint64:
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return castUint(v)
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case reflect.Uintptr:
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vv, err := castUint(v)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(uintptr(vv.Uint())), nil
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case reflect.String:
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return castString(v)
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case reflect.Bool:
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return castBool(v)
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case reflect.Float32:
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vv, err := castFloat(v)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(float32(vv.Float())), nil
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case reflect.Float64:
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return castFloat(v)
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case reflect.Array:
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return castArray(t, v)
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case reflect.Slice:
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return castSlice(t, v)
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case reflect.Map:
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return castMap(t, v)
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case reflect.Struct:
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return castStruct(t, v)
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}
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return v, nil
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}
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func castInt(v reflect.Value) (reflect.Value, error) {
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switch v.Type().Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return v, nil
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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return reflect.ValueOf(int64(v.Uint())), nil
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case reflect.String:
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i64, err := strconv.ParseInt(v.String(), 10, 64)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(i64), nil
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case reflect.Bool:
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if v.Bool() {
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return reflect.ValueOf(int64(1)), nil
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}
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return reflect.ValueOf(int64(0)), nil
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case reflect.Float32, reflect.Float64:
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return reflect.ValueOf(int64(v.Float())), nil
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case reflect.Array:
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if v.Len() > 0 {
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return castInt(v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to int64 from empty array")
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case reflect.Slice:
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if v.Len() > 0 {
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return castInt(v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to int64 from empty slice")
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case reflect.Interface:
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return castInt(reflect.ValueOf(v.Interface()))
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case reflect.Map:
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return nilValue, fmt.Errorf("failed to cast to int64 from map")
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case reflect.Struct:
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return nilValue, fmt.Errorf("failed to cast to int64 from struct")
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case reflect.Ptr:
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return castInt(v.Elem())
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}
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return nilValue, fmt.Errorf("failed to cast to int64 from %s", v.Type().Kind())
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}
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func castUint(v reflect.Value) (reflect.Value, error) {
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switch v.Type().Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return reflect.ValueOf(uint64(v.Int())), nil
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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return v, nil
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case reflect.String:
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u64, err := strconv.ParseUint(v.String(), 10, 64)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(u64), nil
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case reflect.Bool:
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if v.Bool() {
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return reflect.ValueOf(uint64(1)), nil
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}
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return reflect.ValueOf(uint64(0)), nil
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case reflect.Float32, reflect.Float64:
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return reflect.ValueOf(uint64(v.Float())), nil
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case reflect.Array:
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if v.Len() > 0 {
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return castUint(v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to uint64 from empty array")
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case reflect.Slice:
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if v.Len() > 0 {
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return castUint(v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to uint64 from empty slice")
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case reflect.Interface:
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return castUint(reflect.ValueOf(v.Interface()))
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case reflect.Map:
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return nilValue, fmt.Errorf("failed to cast to uint64 from map")
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case reflect.Struct:
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return nilValue, fmt.Errorf("failed to cast to uint64 from struct")
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case reflect.Ptr:
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return castUint(v.Elem())
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}
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return nilValue, fmt.Errorf("failed to cast to uint64 from %s", v.Type().Kind())
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}
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func castString(v reflect.Value) (reflect.Value, error) {
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switch v.Type().Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return reflect.ValueOf(fmt.Sprint(v.Int())), nil
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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return reflect.ValueOf(fmt.Sprint(v.Uint())), nil
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case reflect.String:
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return v, nil
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case reflect.Bool:
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if v.Bool() {
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return reflect.ValueOf("true"), nil
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}
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return reflect.ValueOf("false"), nil
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case reflect.Float32, reflect.Float64:
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return reflect.ValueOf(fmt.Sprint(v.Float())), nil
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case reflect.Array:
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if v.Len() > 0 {
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return castString(v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to string from empty array")
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case reflect.Slice:
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if v.Len() > 0 {
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return castString(v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to string from empty slice")
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case reflect.Interface:
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return castString(reflect.ValueOf(v.Interface()))
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case reflect.Map:
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return nilValue, fmt.Errorf("failed to cast to string from map")
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case reflect.Struct:
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return nilValue, fmt.Errorf("failed to cast to string from struct")
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case reflect.Ptr:
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return castString(v.Elem())
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}
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return nilValue, fmt.Errorf("failed to cast to string from %s", v.Type().Kind())
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}
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func castBool(v reflect.Value) (reflect.Value, error) {
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switch v.Type().Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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switch v.Int() {
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case 0:
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return reflect.ValueOf(false), nil
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case 1:
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return reflect.ValueOf(true), nil
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}
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return nilValue, fmt.Errorf("failed to cast to bool from %d", v.Int())
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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switch v.Uint() {
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case 0:
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return reflect.ValueOf(false), nil
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case 1:
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return reflect.ValueOf(true), nil
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}
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return nilValue, fmt.Errorf("failed to cast to bool from %d", v.Uint())
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case reflect.String:
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b, err := strconv.ParseBool(v.String())
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(b), nil
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case reflect.Bool:
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return v, nil
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case reflect.Float32, reflect.Float64:
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switch v.Float() {
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case 0:
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return reflect.ValueOf(false), nil
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case 1:
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return reflect.ValueOf(true), nil
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}
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return nilValue, fmt.Errorf("failed to cast to bool from %f", v.Float())
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case reflect.Array:
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if v.Len() > 0 {
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return castBool(v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to string from empty array")
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case reflect.Slice:
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if v.Len() > 0 {
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return castBool(v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to string from empty slice")
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case reflect.Interface:
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return castBool(reflect.ValueOf(v.Interface()))
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case reflect.Map:
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return nilValue, fmt.Errorf("failed to cast to string from map")
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case reflect.Struct:
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return nilValue, fmt.Errorf("failed to cast to string from struct")
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case reflect.Ptr:
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return castBool(v.Elem())
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}
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return nilValue, fmt.Errorf("failed to cast to bool from %s", v.Type().Kind())
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}
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func castFloat(v reflect.Value) (reflect.Value, error) {
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switch v.Type().Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return reflect.ValueOf(float64(v.Int())), nil
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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return reflect.ValueOf(float64(v.Uint())), nil
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case reflect.String:
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f64, err := strconv.ParseFloat(v.String(), 64)
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if err != nil {
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return nilValue, err
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}
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return reflect.ValueOf(f64), nil
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case reflect.Bool:
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if v.Bool() {
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return reflect.ValueOf(float64(1)), nil
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}
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return reflect.ValueOf(float64(0)), nil
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case reflect.Float32, reflect.Float64:
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return v, nil
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case reflect.Array:
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if v.Len() > 0 {
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return castFloat(v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to float64 from empty array")
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case reflect.Slice:
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if v.Len() > 0 {
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return castFloat(v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to float64 from empty slice")
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case reflect.Interface:
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return castFloat(reflect.ValueOf(v.Interface()))
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case reflect.Map:
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return nilValue, fmt.Errorf("failed to cast to float64 from map")
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case reflect.Struct:
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return nilValue, fmt.Errorf("failed to cast to float64 from struct")
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case reflect.Ptr:
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return castFloat(v.Elem())
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}
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return nilValue, fmt.Errorf("failed to cast to float64 from %s", v.Type().Kind())
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}
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func castArray(t reflect.Type, v reflect.Value) (reflect.Value, error) {
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kind := v.Type().Kind()
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if kind == reflect.Interface {
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return castArray(t, reflect.ValueOf(v.Interface()))
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}
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if kind != reflect.Slice && kind != reflect.Array {
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return nilValue, fmt.Errorf("failed to cast to array from %s", kind)
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}
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if t.Elem() == v.Type().Elem() {
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return v, nil
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}
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if t.Len() != v.Len() {
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return nilValue, fmt.Errorf("failed to cast [%d]array from slice of %d length", t.Len(), v.Len())
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}
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ret := reflect.New(t).Elem()
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for i := 0; i < v.Len(); i++ {
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vv, err := castValue(t.Elem(), v.Index(i))
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if err != nil {
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return nilValue, err
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}
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ret.Index(i).Set(vv)
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}
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return ret, nil
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}
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func castSlice(t reflect.Type, v reflect.Value) (reflect.Value, error) {
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kind := v.Type().Kind()
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if kind == reflect.Interface {
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return castSlice(t, reflect.ValueOf(v.Interface()))
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}
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if kind != reflect.Slice && kind != reflect.Array {
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return nilValue, fmt.Errorf("failed to cast to slice from %s", kind)
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}
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if t.Elem() == v.Type().Elem() {
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return v, nil
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}
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ret := reflect.MakeSlice(t, v.Len(), v.Len())
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for i := 0; i < v.Len(); i++ {
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vv, err := castValue(t.Elem(), v.Index(i))
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if err != nil {
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return nilValue, err
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}
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ret.Index(i).Set(vv)
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}
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return ret, nil
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}
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func castMap(t reflect.Type, v reflect.Value) (reflect.Value, error) {
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ret := reflect.MakeMap(t)
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switch v.Type().Kind() {
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case reflect.Map:
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iter := v.MapRange()
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for iter.Next() {
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key, err := castValue(t.Key(), iter.Key())
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if err != nil {
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return nilValue, err
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}
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value, err := castValue(t.Elem(), iter.Value())
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if err != nil {
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return nilValue, err
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}
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ret.SetMapIndex(key, value)
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}
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return ret, nil
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case reflect.Interface:
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return castMap(t, reflect.ValueOf(v.Interface()))
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case reflect.Slice:
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if v.Len() > 0 {
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return castMap(t, v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to map from empty slice")
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}
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return nilValue, fmt.Errorf("failed to cast to map from %s", v.Type().Kind())
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}
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func castStruct(t reflect.Type, v reflect.Value) (reflect.Value, error) {
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ret := reflect.New(t).Elem()
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switch v.Type().Kind() {
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case reflect.Map:
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iter := v.MapRange()
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for iter.Next() {
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key := iter.Key()
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k, err := castString(key)
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if err != nil {
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return nilValue, err
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}
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fieldName := k.String()
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field, ok := t.FieldByName(fieldName)
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if ok {
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value, err := castValue(field.Type, iter.Value())
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if err != nil {
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return nilValue, err
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}
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ret.FieldByName(fieldName).Set(value)
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}
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}
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return ret, nil
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case reflect.Struct:
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for i := 0; i < v.Type().NumField(); i++ {
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name := v.Type().Field(i).Name
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ret.FieldByName(name).Set(v.FieldByName(name))
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}
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return ret, nil
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case reflect.Interface:
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return castStruct(t, reflect.ValueOf(v.Interface()))
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case reflect.Slice:
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if v.Len() > 0 {
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return castStruct(t, v.Index(0))
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}
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return nilValue, fmt.Errorf("failed to cast to struct from empty slice")
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default:
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return nilValue, fmt.Errorf("failed to cast to struct from %s", v.Type().Kind())
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}
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}
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