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- // 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 cmpopts provides common options for the cmp package.
- package cmpopts
-
- import (
- "math"
- "reflect"
-
- "github.com/google/go-cmp/cmp"
- )
-
- func equateAlways(_, _ interface{}) bool { return true }
-
- // EquateEmpty returns a Comparer option that determines all maps and slices
- // with a length of zero to be equal, regardless of whether they are nil.
- //
- // EquateEmpty can be used in conjunction with SortSlices and SortMaps.
- func EquateEmpty() cmp.Option {
- return cmp.FilterValues(isEmpty, cmp.Comparer(equateAlways))
- }
-
- func isEmpty(x, y interface{}) bool {
- vx, vy := reflect.ValueOf(x), reflect.ValueOf(y)
- return (x != nil && y != nil && vx.Type() == vy.Type()) &&
- (vx.Kind() == reflect.Slice || vx.Kind() == reflect.Map) &&
- (vx.Len() == 0 && vy.Len() == 0)
- }
-
- // EquateApprox returns a Comparer option that determines float32 or float64
- // values to be equal if they are within a relative fraction or absolute margin.
- // This option is not used when either x or y is NaN or infinite.
- //
- // The fraction determines that the difference of two values must be within the
- // smaller fraction of the two values, while the margin determines that the two
- // values must be within some absolute margin.
- // To express only a fraction or only a margin, use 0 for the other parameter.
- // The fraction and margin must be non-negative.
- //
- // The mathematical expression used is equivalent to:
- // |x-y| ≤ max(fraction*min(|x|, |y|), margin)
- //
- // EquateApprox can be used in conjunction with EquateNaNs.
- func EquateApprox(fraction, margin float64) cmp.Option {
- if margin < 0 || fraction < 0 || math.IsNaN(margin) || math.IsNaN(fraction) {
- panic("margin or fraction must be a non-negative number")
- }
- a := approximator{fraction, margin}
- return cmp.Options{
- cmp.FilterValues(areRealF64s, cmp.Comparer(a.compareF64)),
- cmp.FilterValues(areRealF32s, cmp.Comparer(a.compareF32)),
- }
- }
-
- type approximator struct{ frac, marg float64 }
-
- func areRealF64s(x, y float64) bool {
- return !math.IsNaN(x) && !math.IsNaN(y) && !math.IsInf(x, 0) && !math.IsInf(y, 0)
- }
- func areRealF32s(x, y float32) bool {
- return areRealF64s(float64(x), float64(y))
- }
- func (a approximator) compareF64(x, y float64) bool {
- relMarg := a.frac * math.Min(math.Abs(x), math.Abs(y))
- return math.Abs(x-y) <= math.Max(a.marg, relMarg)
- }
- func (a approximator) compareF32(x, y float32) bool {
- return a.compareF64(float64(x), float64(y))
- }
-
- // EquateNaNs returns a Comparer option that determines float32 and float64
- // NaN values to be equal.
- //
- // EquateNaNs can be used in conjunction with EquateApprox.
- func EquateNaNs() cmp.Option {
- return cmp.Options{
- cmp.FilterValues(areNaNsF64s, cmp.Comparer(equateAlways)),
- cmp.FilterValues(areNaNsF32s, cmp.Comparer(equateAlways)),
- }
- }
-
- func areNaNsF64s(x, y float64) bool {
- return math.IsNaN(x) && math.IsNaN(y)
- }
- func areNaNsF32s(x, y float32) bool {
- return areNaNsF64s(float64(x), float64(y))
- }
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