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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cldr
import (
"fmt"
"reflect"
"sort"
)
// Slice provides utilities for modifying slices of elements.
// It can be wrapped around any slice of which the element type implements
// interface Elem.
type Slice struct {
ptr reflect.Value
typ reflect.Type
}
// Value returns the reflect.Value of the underlying slice.
func (s *Slice) Value() reflect.Value {
return s.ptr.Elem()
}
// MakeSlice wraps a pointer to a slice of Elems.
// It replaces the array pointed to by the slice so that subsequent modifications
// do not alter the data in a CLDR type.
// It panics if an incorrect type is passed.
func MakeSlice(slicePtr interface{}) Slice {
ptr := reflect.ValueOf(slicePtr)
if ptr.Kind() != reflect.Ptr {
panic(fmt.Sprintf("MakeSlice: argument must be pointer to slice, found %v", ptr.Type()))
}
sl := ptr.Elem()
if sl.Kind() != reflect.Slice {
panic(fmt.Sprintf("MakeSlice: argument must point to a slice, found %v", sl.Type()))
}
intf := reflect.TypeOf((*Elem)(nil)).Elem()
if !sl.Type().Elem().Implements(intf) {
panic(fmt.Sprintf("MakeSlice: element type of slice (%v) does not implement Elem", sl.Type().Elem()))
}
nsl := reflect.MakeSlice(sl.Type(), sl.Len(), sl.Len())
reflect.Copy(nsl, sl)
sl.Set(nsl)
return Slice{
ptr: ptr,
typ: sl.Type().Elem().Elem(),
}
}
func (s Slice) indexForAttr(a string) []int {
for i := iter(reflect.Zero(s.typ)); !i.done(); i.next() {
if n, _ := xmlName(i.field()); n == a {
return i.index
}
}
panic(fmt.Sprintf("MakeSlice: no attribute %q for type %v", a, s.typ))
}
// Filter filters s to only include elements for which fn returns true.
func (s Slice) Filter(fn func(e Elem) bool) {
k := 0
sl := s.Value()
for i := 0; i < sl.Len(); i++ {
vi := sl.Index(i)
if fn(vi.Interface().(Elem)) {
sl.Index(k).Set(vi)
k++
}
}
sl.Set(sl.Slice(0, k))
}
// Group finds elements in s for which fn returns the same value and groups
// them in a new Slice.
func (s Slice) Group(fn func(e Elem) string) []Slice {
m := make(map[string][]reflect.Value)
sl := s.Value()
for i := 0; i < sl.Len(); i++ {
vi := sl.Index(i)
key := fn(vi.Interface().(Elem))
m[key] = append(m[key], vi)
}
keys := []string{}
for k, _ := range m {
keys = append(keys, k)
}
sort.Strings(keys)
res := []Slice{}
for _, k := range keys {
nsl := reflect.New(sl.Type())
nsl.Elem().Set(reflect.Append(nsl.Elem(), m[k]...))
res = append(res, MakeSlice(nsl.Interface()))
}
return res
}
// SelectAnyOf filters s to contain only elements for which attr matches
// any of the values.
func (s Slice) SelectAnyOf(attr string, values ...string) {
index := s.indexForAttr(attr)
s.Filter(func(e Elem) bool {
vf := reflect.ValueOf(e).Elem().FieldByIndex(index)
return in(values, vf.String())
})
}
// SelectOnePerGroup filters s to include at most one element e per group of
// elements matching Key(attr), where e has an attribute a that matches any
// the values in v.
// If more than one element in a group matches a value in v preference
// is given to the element that matches the first value in v.
func (s Slice) SelectOnePerGroup(a string, v []string) {
index := s.indexForAttr(a)
grouped := s.Group(func(e Elem) string { return Key(e, a) })
sl := s.Value()
sl.Set(sl.Slice(0, 0))
for _, g := range grouped {
e := reflect.Value{}
found := len(v)
gsl := g.Value()
for i := 0; i < gsl.Len(); i++ {
vi := gsl.Index(i).Elem().FieldByIndex(index)
j := 0
for ; j < len(v) && v[j] != vi.String(); j++ {
}
if j < found {
found = j
e = gsl.Index(i)
}
}
if found < len(v) {
sl.Set(reflect.Append(sl, e))
}
}
}
// SelectDraft drops all elements from the list with a draft level smaller than d
// and selects the highest draft level of the remaining.
// This method assumes that the input CLDR is canonicalized.
func (s Slice) SelectDraft(d Draft) {
s.SelectOnePerGroup("draft", drafts[len(drafts)-2-int(d):])
}
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