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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:19:13 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:19:13 +0000 |
commit | ccd992355df7192993c666236047820244914598 (patch) | |
tree | f00fea65147227b7743083c6148396f74cd66935 /src/cmp/cmp.go | |
parent | Initial commit. (diff) | |
download | golang-1.21-ccd992355df7192993c666236047820244914598.tar.xz golang-1.21-ccd992355df7192993c666236047820244914598.zip |
Adding upstream version 1.21.8.upstream/1.21.8
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/cmp/cmp.go')
-rw-r--r-- | src/cmp/cmp.go | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/src/cmp/cmp.go b/src/cmp/cmp.go new file mode 100644 index 0000000..0fba5c1 --- /dev/null +++ b/src/cmp/cmp.go @@ -0,0 +1,59 @@ +// Copyright 2023 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 cmp provides types and functions related to comparing +// ordered values. +package cmp + +// Ordered is a constraint that permits any ordered type: any type +// that supports the operators < <= >= >. +// If future releases of Go add new ordered types, +// this constraint will be modified to include them. +// +// Note that floating-point types may contain NaN ("not-a-number") values. +// An operator such as == or < will always report false when +// comparing a NaN value with any other value, NaN or not. +// See the [Compare] function for a consistent way to compare NaN values. +type Ordered interface { + ~int | ~int8 | ~int16 | ~int32 | ~int64 | + ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr | + ~float32 | ~float64 | + ~string +} + +// Less reports whether x is less than y. +// For floating-point types, a NaN is considered less than any non-NaN, +// and -0.0 is not less than (is equal to) 0.0. +func Less[T Ordered](x, y T) bool { + return (isNaN(x) && !isNaN(y)) || x < y +} + +// Compare returns +// +// -1 if x is less than y, +// 0 if x equals y, +// +1 if x is greater than y. +// +// For floating-point types, a NaN is considered less than any non-NaN, +// a NaN is considered equal to a NaN, and -0.0 is equal to 0.0. +func Compare[T Ordered](x, y T) int { + xNaN := isNaN(x) + yNaN := isNaN(y) + if xNaN && yNaN { + return 0 + } + if xNaN || x < y { + return -1 + } + if yNaN || x > y { + return +1 + } + return 0 +} + +// isNaN reports whether x is a NaN without requiring the math package. +// This will always return false if T is not floating-point. +func isNaN[T Ordered](x T) bool { + return x != x +} |