1// Copyright 2021 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 slices defines various functions useful with slices of any type.
6package slices
7
8import (
9 "cmp"
10 "slices"
11)
12
13// Equal reports whether two slices are equal: the same length and all
14// elements equal. If the lengths are different, Equal returns false.
15// Otherwise, the elements are compared in increasing index order, and the
16// comparison stops at the first unequal pair.
17// Floating point NaNs are not considered equal.
18//
19//go:fix inline
20func Equal[S ~[]E, E comparable](s1, s2 S) bool {
21 return slices.Equal(s1, s2)
22}
23
24// EqualFunc reports whether two slices are equal using an equality
25// function on each pair of elements. If the lengths are different,
26// EqualFunc returns false. Otherwise, the elements are compared in
27// increasing index order, and the comparison stops at the first index
28// for which eq returns false.
29//
30//go:fix inline
31func EqualFunc[S1 ~[]E1, S2 ~[]E2, E1, E2 any](s1 S1, s2 S2, eq func(E1, E2) bool) bool {
32 return slices.EqualFunc(s1, s2, eq)
33}
34
35// Compare compares the elements of s1 and s2, using [cmp.Compare] on each pair
36// of elements. The elements are compared sequentially, starting at index 0,
37// until one element is not equal to the other.
38// The result of comparing the first non-matching elements is returned.
39// If both slices are equal until one of them ends, the shorter slice is
40// considered less than the longer one.
41// The result is 0 if s1 == s2, -1 if s1 < s2, and +1 if s1 > s2.
42//
43//go:fix inline
44func Compare[S ~[]E, E cmp.Ordered](s1, s2 S) int {
45 return slices.Compare(s1, s2)
46}
47
48// CompareFunc is like [Compare] but uses a custom comparison function on each
49// pair of elements.
50// The result is the first non-zero result of cmp; if cmp always
51// returns 0 the result is 0 if len(s1) == len(s2), -1 if len(s1) < len(s2),
52// and +1 if len(s1) > len(s2).
53//
54//go:fix inline
55func CompareFunc[S1 ~[]E1, S2 ~[]E2, E1, E2 any](s1 S1, s2 S2, cmp func(E1, E2) int) int {
56 return slices.CompareFunc(s1, s2, cmp)
57}
58
59// Index returns the index of the first occurrence of v in s,
60// or -1 if not present.
61//
62//go:fix inline
63func Index[S ~[]E, E comparable](s S, v E) int {
64 return slices.Index(s, v)
65}
66
67// IndexFunc returns the first index i satisfying f(s[i]),
68// or -1 if none do.
69//
70//go:fix inline
71func IndexFunc[S ~[]E, E any](s S, f func(E) bool) int {
72 return slices.IndexFunc(s, f)
73}
74
75// Contains reports whether v is present in s.
76//
77//go:fix inline
78func Contains[S ~[]E, E comparable](s S, v E) bool {
79 return slices.Contains(s, v)
80}
81
82// ContainsFunc reports whether at least one
83// element e of s satisfies f(e).
84//
85//go:fix inline
86func ContainsFunc[S ~[]E, E any](s S, f func(E) bool) bool {
87 return slices.ContainsFunc(s, f)
88}
89
90// Insert inserts the values v... into s at index i,
91// returning the modified slice.
92// The elements at s[i:] are shifted up to make room.
93// In the returned slice r, r[i] == v[0],
94// and r[i+len(v)] == value originally at r[i].
95// Insert panics if i is out of range.
96// This function is O(len(s) + len(v)).
97//
98//go:fix inline
99func Insert[S ~[]E, E any](s S, i int, v ...E) S {
100 return slices.Insert(s, i, v...)
101}
102
103// Delete removes the elements s[i:j] from s, returning the modified slice.
104// Delete panics if j > len(s) or s[i:j] is not a valid slice of s.
105// Delete is O(len(s)-i), so if many items must be deleted, it is better to
106// make a single call deleting them all together than to delete one at a time.
107// Delete zeroes the elements s[len(s)-(j-i):len(s)].
108//
109//go:fix inline
110func Delete[S ~[]E, E any](s S, i, j int) S {
111 return slices.Delete(s, i, j)
112}
113
114// DeleteFunc removes any elements from s for which del returns true,
115// returning the modified slice.
116// DeleteFunc zeroes the elements between the new length and the original length.
117//
118//go:fix inline
119func DeleteFunc[S ~[]E, E any](s S, del func(E) bool) S {
120 return slices.DeleteFunc(s, del)
121}
122
123// Replace replaces the elements s[i:j] by the given v, and returns the
124// modified slice. Replace panics if s[i:j] is not a valid slice of s.
125// When len(v) < (j-i), Replace zeroes the elements between the new length and the original length.
126//
127//go:fix inline
128func Replace[S ~[]E, E any](s S, i, j int, v ...E) S {
129 return slices.Replace(s, i, j, v...)
130}
131
132// Clone returns a copy of the slice.
133// The elements are copied using assignment, so this is a shallow clone.
134//
135//go:fix inline
136func Clone[S ~[]E, E any](s S) S {
137 return slices.Clone(s)
138}
139
140// Compact replaces consecutive runs of equal elements with a single copy.
141// This is like the uniq command found on Unix.
142// Compact modifies the contents of the slice s and returns the modified slice,
143// which may have a smaller length.
144// Compact zeroes the elements between the new length and the original length.
145//
146//go:fix inline
147func Compact[S ~[]E, E comparable](s S) S {
148 return slices.Compact(s)
149}
150
151// CompactFunc is like [Compact] but uses an equality function to compare elements.
152// For runs of elements that compare equal, CompactFunc keeps the first one.
153// CompactFunc zeroes the elements between the new length and the original length.
154//
155//go:fix inline
156func CompactFunc[S ~[]E, E any](s S, eq func(E, E) bool) S {
157 return slices.CompactFunc(s, eq)
158}
159
160// Grow increases the slice's capacity, if necessary, to guarantee space for
161// another n elements. After Grow(n), at least n elements can be appended
162// to the slice without another allocation. If n is negative or too large to
163// allocate the memory, Grow panics.
164//
165//go:fix inline
166func Grow[S ~[]E, E any](s S, n int) S {
167 return slices.Grow(s, n)
168}
169
170// Clip removes unused capacity from the slice, returning s[:len(s):len(s)].
171//
172//go:fix inline
173func Clip[S ~[]E, E any](s S) S {
174 return slices.Clip(s)
175}
176
177// Reverse reverses the elements of the slice in place.
178//
179//go:fix inline
180func Reverse[S ~[]E, E any](s S) {
181 slices.Reverse(s)
182}