47 lines
1.3 KiB
Go
47 lines
1.3 KiB
Go
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package slices
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import (
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"reflect"
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"github.com/bradfitz/iter"
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)
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// Returns a copy of all the elements of slice []T as a slice of interface{}.
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func ToEmptyInterface(slice interface{}) (ret []interface{}) {
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v := reflect.ValueOf(slice)
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l := v.Len()
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ret = make([]interface{}, 0, l)
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for i := range iter.N(v.Len()) {
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ret = append(ret, v.Index(i).Interface())
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}
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return
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}
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// Makes and sets a slice at *ptrTo, and type asserts all the elements from
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// from to it.
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func MakeInto(ptrTo interface{}, from interface{}) {
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fromSliceValue := reflect.ValueOf(from)
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fromLen := fromSliceValue.Len()
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if fromLen == 0 {
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return
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}
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// Deref the pointer to slice.
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slicePtrValue := reflect.ValueOf(ptrTo)
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if slicePtrValue.Kind() != reflect.Ptr {
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panic("destination is not a pointer")
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}
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destSliceValue := slicePtrValue.Elem()
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// The type of the elements of the destination slice.
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destSliceElemType := destSliceValue.Type().Elem()
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destSliceValue.Set(reflect.MakeSlice(destSliceValue.Type(), fromLen, fromLen))
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for i := range iter.N(fromSliceValue.Len()) {
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// The value inside the interface in the slice element.
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itemValue := fromSliceValue.Index(i)
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if itemValue.Kind() == reflect.Interface {
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itemValue = itemValue.Elem()
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}
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convertedItem := itemValue.Convert(destSliceElemType)
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destSliceValue.Index(i).Set(convertedItem)
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}
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}
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