diff options
Diffstat (limited to 'vendor/github.com/google/go-cmp/cmp/internal/value/sort.go')
-rw-r--r-- | vendor/github.com/google/go-cmp/cmp/internal/value/sort.go | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/vendor/github.com/google/go-cmp/cmp/internal/value/sort.go b/vendor/github.com/google/go-cmp/cmp/internal/value/sort.go new file mode 100644 index 00000000..fe8aa27a --- /dev/null +++ b/vendor/github.com/google/go-cmp/cmp/internal/value/sort.go @@ -0,0 +1,111 @@ +// Copyright 2017, 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.md file. + +package value + +import ( + "fmt" + "math" + "reflect" + "sort" +) + +// SortKeys sorts a list of map keys, deduplicating keys if necessary. +// The type of each value must be comparable. +func SortKeys(vs []reflect.Value) []reflect.Value { + if len(vs) == 0 { + return vs + } + + // Sort the map keys. + sort.Sort(valueSorter(vs)) + + // Deduplicate keys (fails for NaNs). + vs2 := vs[:1] + for _, v := range vs[1:] { + if isLess(vs2[len(vs2)-1], v) { + vs2 = append(vs2, v) + } + } + return vs2 +} + +// TODO: Use sort.Slice once Google AppEngine is on Go1.8 or above. +type valueSorter []reflect.Value + +func (vs valueSorter) Len() int { return len(vs) } +func (vs valueSorter) Less(i, j int) bool { return isLess(vs[i], vs[j]) } +func (vs valueSorter) Swap(i, j int) { vs[i], vs[j] = vs[j], vs[i] } + +// isLess is a generic function for sorting arbitrary map keys. +// The inputs must be of the same type and must be comparable. +func isLess(x, y reflect.Value) bool { + switch x.Type().Kind() { + case reflect.Bool: + return !x.Bool() && y.Bool() + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + return x.Int() < y.Int() + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + return x.Uint() < y.Uint() + case reflect.Float32, reflect.Float64: + fx, fy := x.Float(), y.Float() + return fx < fy || math.IsNaN(fx) && !math.IsNaN(fy) + case reflect.Complex64, reflect.Complex128: + cx, cy := x.Complex(), y.Complex() + rx, ix, ry, iy := real(cx), imag(cx), real(cy), imag(cy) + if rx == ry || (math.IsNaN(rx) && math.IsNaN(ry)) { + return ix < iy || math.IsNaN(ix) && !math.IsNaN(iy) + } + return rx < ry || math.IsNaN(rx) && !math.IsNaN(ry) + case reflect.Ptr, reflect.UnsafePointer, reflect.Chan: + return x.Pointer() < y.Pointer() + case reflect.String: + return x.String() < y.String() + case reflect.Array: + for i := 0; i < x.Len(); i++ { + if isLess(x.Index(i), y.Index(i)) { + return true + } + if isLess(y.Index(i), x.Index(i)) { + return false + } + } + return false + case reflect.Struct: + for i := 0; i < x.NumField(); i++ { + if isLess(x.Field(i), y.Field(i)) { + return true + } + if isLess(y.Field(i), x.Field(i)) { + return false + } + } + return false + case reflect.Interface: + vx, vy := x.Elem(), y.Elem() + if !vx.IsValid() || !vy.IsValid() { + return !vx.IsValid() && vy.IsValid() + } + tx, ty := vx.Type(), vy.Type() + if tx == ty { + return isLess(x.Elem(), y.Elem()) + } + if tx.Kind() != ty.Kind() { + return vx.Kind() < vy.Kind() + } + if tx.String() != ty.String() { + return tx.String() < ty.String() + } + if tx.PkgPath() != ty.PkgPath() { + return tx.PkgPath() < ty.PkgPath() + } + // This can happen in rare situations, so we fallback to just comparing + // the unique pointer for a reflect.Type. This guarantees deterministic + // ordering within a program, but it is obviously not stable. + return reflect.ValueOf(vx.Type()).Pointer() < reflect.ValueOf(vy.Type()).Pointer() + default: + // Must be Func, Map, or Slice; which are not comparable. + panic(fmt.Sprintf("%T is not comparable", x.Type())) + } +} |