diff options
Diffstat (limited to '')
-rw-r--r-- | dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/slices/slices.go | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/slices/slices.go b/dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/slices/slices.go new file mode 100644 index 0000000..8a237c5 --- /dev/null +++ b/dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/slices/slices.go @@ -0,0 +1,218 @@ +// Copyright 2021 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 slices defines various functions useful with slices of any type. +// Unless otherwise specified, these functions all apply to the elements +// of a slice at index 0 <= i < len(s). +// +// Note that the less function in IsSortedFunc, SortFunc, SortStableFunc requires a +// strict weak ordering (https://en.wikipedia.org/wiki/Weak_ordering#Strict_weak_orderings), +// or the sorting may fail to sort correctly. A common case is when sorting slices of +// floating-point numbers containing NaN values. +package slices + +import "golang.org/x/exp/constraints" + +// Equal reports whether two slices are equal: the same length and all +// elements equal. If the lengths are different, Equal returns false. +// Otherwise, the elements are compared in increasing index order, and the +// comparison stops at the first unequal pair. +// Floating point NaNs are not considered equal. +func Equal[E comparable](s1, s2 []E) bool { + if len(s1) != len(s2) { + return false + } + for i := range s1 { + if s1[i] != s2[i] { + return false + } + } + return true +} + +// EqualFunc reports whether two slices are equal using a comparison +// function on each pair of elements. If the lengths are different, +// EqualFunc returns false. Otherwise, the elements are compared in +// increasing index order, and the comparison stops at the first index +// for which eq returns false. +func EqualFunc[E1, E2 any](s1 []E1, s2 []E2, eq func(E1, E2) bool) bool { + if len(s1) != len(s2) { + return false + } + for i, v1 := range s1 { + v2 := s2[i] + if !eq(v1, v2) { + return false + } + } + return true +} + +// Compare compares the elements of s1 and s2. +// The elements are compared sequentially, starting at index 0, +// until one element is not equal to the other. +// The result of comparing the first non-matching elements is returned. +// If both slices are equal until one of them ends, the shorter slice is +// considered less than the longer one. +// The result is 0 if s1 == s2, -1 if s1 < s2, and +1 if s1 > s2. +// Comparisons involving floating point NaNs are ignored. +func Compare[E constraints.Ordered](s1, s2 []E) int { + s2len := len(s2) + for i, v1 := range s1 { + if i >= s2len { + return +1 + } + v2 := s2[i] + switch { + case v1 < v2: + return -1 + case v1 > v2: + return +1 + } + } + if len(s1) < s2len { + return -1 + } + return 0 +} + +// CompareFunc is like Compare but uses a comparison function +// on each pair of elements. The elements are compared in increasing +// index order, and the comparisons stop after the first time cmp +// returns non-zero. +// The result is the first non-zero result of cmp; if cmp always +// returns 0 the result is 0 if len(s1) == len(s2), -1 if len(s1) < len(s2), +// and +1 if len(s1) > len(s2). +func CompareFunc[E1, E2 any](s1 []E1, s2 []E2, cmp func(E1, E2) int) int { + s2len := len(s2) + for i, v1 := range s1 { + if i >= s2len { + return +1 + } + v2 := s2[i] + if c := cmp(v1, v2); c != 0 { + return c + } + } + if len(s1) < s2len { + return -1 + } + return 0 +} + +// Index returns the index of the first occurrence of v in s, +// or -1 if not present. +func Index[E comparable](s []E, v E) int { + for i, vs := range s { + if v == vs { + return i + } + } + return -1 +} + +// IndexFunc returns the first index i satisfying f(s[i]), +// or -1 if none do. +func IndexFunc[E any](s []E, f func(E) bool) int { + for i, v := range s { + if f(v) { + return i + } + } + return -1 +} + +// Contains reports whether v is present in s. +func Contains[E comparable](s []E, v E) bool { + return Index(s, v) >= 0 +} + +// Insert inserts the values v... into s at index i, +// returning the modified slice. +// In the returned slice r, r[i] == v[0]. +// Insert panics if i is out of range. +// This function is O(len(s) + len(v)). +func Insert[S ~[]E, E any](s S, i int, v ...E) S { + tot := len(s) + len(v) + if tot <= cap(s) { + s2 := s[:tot] + copy(s2[i+len(v):], s[i:]) + copy(s2[i:], v) + return s2 + } + s2 := make(S, tot) + copy(s2, s[:i]) + copy(s2[i:], v) + copy(s2[i+len(v):], s[i:]) + return s2 +} + +// Delete removes the elements s[i:j] from s, returning the modified slice. +// Delete panics if s[i:j] is not a valid slice of s. +// Delete modifies the contents of the slice s; it does not create a new slice. +// Delete is O(len(s)-(j-i)), so if many items must be deleted, it is better to +// make a single call deleting them all together than to delete one at a time. +func Delete[S ~[]E, E any](s S, i, j int) S { + return append(s[:i], s[j:]...) +} + +// Clone returns a copy of the slice. +// The elements are copied using assignment, so this is a shallow clone. +func Clone[S ~[]E, E any](s S) S { + // Preserve nil in case it matters. + if s == nil { + return nil + } + return append(S([]E{}), s...) +} + +// Compact replaces consecutive runs of equal elements with a single copy. +// This is like the uniq command found on Unix. +// Compact modifies the contents of the slice s; it does not create a new slice. +func Compact[S ~[]E, E comparable](s S) S { + if len(s) == 0 { + return s + } + i := 1 + last := s[0] + for _, v := range s[1:] { + if v != last { + s[i] = v + i++ + last = v + } + } + return s[:i] +} + +// CompactFunc is like Compact but uses a comparison function. +func CompactFunc[S ~[]E, E any](s S, eq func(E, E) bool) S { + if len(s) == 0 { + return s + } + i := 1 + last := s[0] + for _, v := range s[1:] { + if !eq(v, last) { + s[i] = v + i++ + last = v + } + } + return s[:i] +} + +// Grow increases the slice's capacity, if necessary, to guarantee space for +// another n elements. After Grow(n), at least n elements can be appended +// to the slice without another allocation. Grow may modify elements of the +// slice between the length and the capacity. If n is negative or too large to +// allocate the memory, Grow panics. +func Grow[S ~[]E, E any](s S, n int) S { + return append(s, make(S, n)...)[:len(s)] +} + +// Clip removes unused capacity from the slice, returning s[:len(s):len(s)]. +func Clip[S ~[]E, E any](s S) S { + return s[:len(s):len(s)] +} |