khenaidoo | ac63710 | 2019-01-14 15:44:34 -0500 | [diff] [blame] | 1 | // Copyright 2013 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package cldr |
| 6 | |
| 7 | import ( |
| 8 | "fmt" |
| 9 | "reflect" |
| 10 | "sort" |
| 11 | ) |
| 12 | |
| 13 | // Slice provides utilities for modifying slices of elements. |
| 14 | // It can be wrapped around any slice of which the element type implements |
| 15 | // interface Elem. |
| 16 | type Slice struct { |
| 17 | ptr reflect.Value |
| 18 | typ reflect.Type |
| 19 | } |
| 20 | |
| 21 | // Value returns the reflect.Value of the underlying slice. |
| 22 | func (s *Slice) Value() reflect.Value { |
| 23 | return s.ptr.Elem() |
| 24 | } |
| 25 | |
| 26 | // MakeSlice wraps a pointer to a slice of Elems. |
| 27 | // It replaces the array pointed to by the slice so that subsequent modifications |
| 28 | // do not alter the data in a CLDR type. |
| 29 | // It panics if an incorrect type is passed. |
| 30 | func MakeSlice(slicePtr interface{}) Slice { |
| 31 | ptr := reflect.ValueOf(slicePtr) |
| 32 | if ptr.Kind() != reflect.Ptr { |
| 33 | panic(fmt.Sprintf("MakeSlice: argument must be pointer to slice, found %v", ptr.Type())) |
| 34 | } |
| 35 | sl := ptr.Elem() |
| 36 | if sl.Kind() != reflect.Slice { |
| 37 | panic(fmt.Sprintf("MakeSlice: argument must point to a slice, found %v", sl.Type())) |
| 38 | } |
| 39 | intf := reflect.TypeOf((*Elem)(nil)).Elem() |
| 40 | if !sl.Type().Elem().Implements(intf) { |
| 41 | panic(fmt.Sprintf("MakeSlice: element type of slice (%v) does not implement Elem", sl.Type().Elem())) |
| 42 | } |
| 43 | nsl := reflect.MakeSlice(sl.Type(), sl.Len(), sl.Len()) |
| 44 | reflect.Copy(nsl, sl) |
| 45 | sl.Set(nsl) |
| 46 | return Slice{ |
| 47 | ptr: ptr, |
| 48 | typ: sl.Type().Elem().Elem(), |
| 49 | } |
| 50 | } |
| 51 | |
| 52 | func (s Slice) indexForAttr(a string) []int { |
| 53 | for i := iter(reflect.Zero(s.typ)); !i.done(); i.next() { |
| 54 | if n, _ := xmlName(i.field()); n == a { |
| 55 | return i.index |
| 56 | } |
| 57 | } |
| 58 | panic(fmt.Sprintf("MakeSlice: no attribute %q for type %v", a, s.typ)) |
| 59 | } |
| 60 | |
| 61 | // Filter filters s to only include elements for which fn returns true. |
| 62 | func (s Slice) Filter(fn func(e Elem) bool) { |
| 63 | k := 0 |
| 64 | sl := s.Value() |
| 65 | for i := 0; i < sl.Len(); i++ { |
| 66 | vi := sl.Index(i) |
| 67 | if fn(vi.Interface().(Elem)) { |
| 68 | sl.Index(k).Set(vi) |
| 69 | k++ |
| 70 | } |
| 71 | } |
| 72 | sl.Set(sl.Slice(0, k)) |
| 73 | } |
| 74 | |
| 75 | // Group finds elements in s for which fn returns the same value and groups |
| 76 | // them in a new Slice. |
| 77 | func (s Slice) Group(fn func(e Elem) string) []Slice { |
| 78 | m := make(map[string][]reflect.Value) |
| 79 | sl := s.Value() |
| 80 | for i := 0; i < sl.Len(); i++ { |
| 81 | vi := sl.Index(i) |
| 82 | key := fn(vi.Interface().(Elem)) |
| 83 | m[key] = append(m[key], vi) |
| 84 | } |
| 85 | keys := []string{} |
| 86 | for k, _ := range m { |
| 87 | keys = append(keys, k) |
| 88 | } |
| 89 | sort.Strings(keys) |
| 90 | res := []Slice{} |
| 91 | for _, k := range keys { |
| 92 | nsl := reflect.New(sl.Type()) |
| 93 | nsl.Elem().Set(reflect.Append(nsl.Elem(), m[k]...)) |
| 94 | res = append(res, MakeSlice(nsl.Interface())) |
| 95 | } |
| 96 | return res |
| 97 | } |
| 98 | |
| 99 | // SelectAnyOf filters s to contain only elements for which attr matches |
| 100 | // any of the values. |
| 101 | func (s Slice) SelectAnyOf(attr string, values ...string) { |
| 102 | index := s.indexForAttr(attr) |
| 103 | s.Filter(func(e Elem) bool { |
| 104 | vf := reflect.ValueOf(e).Elem().FieldByIndex(index) |
| 105 | return in(values, vf.String()) |
| 106 | }) |
| 107 | } |
| 108 | |
| 109 | // SelectOnePerGroup filters s to include at most one element e per group of |
| 110 | // elements matching Key(attr), where e has an attribute a that matches any |
| 111 | // the values in v. |
| 112 | // If more than one element in a group matches a value in v preference |
| 113 | // is given to the element that matches the first value in v. |
| 114 | func (s Slice) SelectOnePerGroup(a string, v []string) { |
| 115 | index := s.indexForAttr(a) |
| 116 | grouped := s.Group(func(e Elem) string { return Key(e, a) }) |
| 117 | sl := s.Value() |
| 118 | sl.Set(sl.Slice(0, 0)) |
| 119 | for _, g := range grouped { |
| 120 | e := reflect.Value{} |
| 121 | found := len(v) |
| 122 | gsl := g.Value() |
| 123 | for i := 0; i < gsl.Len(); i++ { |
| 124 | vi := gsl.Index(i).Elem().FieldByIndex(index) |
| 125 | j := 0 |
| 126 | for ; j < len(v) && v[j] != vi.String(); j++ { |
| 127 | } |
| 128 | if j < found { |
| 129 | found = j |
| 130 | e = gsl.Index(i) |
| 131 | } |
| 132 | } |
| 133 | if found < len(v) { |
| 134 | sl.Set(reflect.Append(sl, e)) |
| 135 | } |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | // SelectDraft drops all elements from the list with a draft level smaller than d |
| 140 | // and selects the highest draft level of the remaining. |
| 141 | // This method assumes that the input CLDR is canonicalized. |
| 142 | func (s Slice) SelectDraft(d Draft) { |
| 143 | s.SelectOnePerGroup("draft", drafts[len(drafts)-2-int(d):]) |
| 144 | } |