2008-09-12 17:12:20 -06:00
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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2009-03-05 18:02:34 -07:00
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// A package of simple functions to manipulate strings.
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2008-09-12 17:12:20 -06:00
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package strings
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2008-12-04 22:00:34 -07:00
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import "utf8"
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2008-09-12 17:12:20 -06:00
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// Explode splits s into an array of UTF-8 sequences, one per Unicode character (still strings).
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// Invalid UTF-8 sequences become correct encodings of U+FFF8.
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func Explode(s string) []string {
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a := make([]string, utf8.RuneCountInString(s, 0, len(s)));
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j := 0;
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var size, rune int;
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for i := 0; i < len(a); i++ {
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rune, size = utf8.DecodeRuneInString(s, j);
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a[i] = string(rune);
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j += size;
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}
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return a
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}
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2009-03-05 18:02:34 -07:00
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// Count counts the number of non-overlapping instances of sep in s.
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func Count(s, sep string) int {
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if sep == "" {
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return utf8.RuneCountInString(s, 0, len(s))+1
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}
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c := sep[0];
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n := 0;
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for i := 0; i+len(sep) <= len(s); i++ {
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if s[i] == c && (len(sep) == 1 || s[i:i+len(sep)] == sep) {
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n++;
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i += len(sep)-1
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}
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}
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return n
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}
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// Index returns the index of the first instance of sep in s.
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func Index(s, sep string) int {
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if sep == "" {
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return 0
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}
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c := sep[0];
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for i := 0; i+len(sep) <= len(s); i++ {
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if s[i] == c && (len(sep) == 1 || s[i:i+len(sep)] == sep) {
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return i
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}
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}
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return -1
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}
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// Split returns the array representing the substrings of s separated by string sep. Adjacent
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// occurrences of sep produce empty substrings. If sep is empty, it is the same as Explode.
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func Split(s, sep string) []string {
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if sep == "" {
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return Explode(s)
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}
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c := sep[0];
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start := 0;
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n := Count(s, sep)+1;
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a := make([]string, n);
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na := 0;
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for i := 0; i+len(sep) <= len(s); i++ {
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if s[i] == c && (len(sep) == 1 || s[i:i+len(sep)] == sep) {
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a[na] = s[start:i];
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na++;
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start = i+len(sep);
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i += len(sep)-1
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}
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}
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a[na] = s[start:len(s)];
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return a
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}
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// Join concatenates the elements of a to create a single string. The separator string
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// sep is placed between elements in the resulting string.
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func Join(a []string, sep string) string {
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if len(a) == 0 {
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return ""
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}
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if len(a) == 1 {
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return a[0]
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}
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n := len(sep) * (len(a)-1);
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for i := 0; i < len(a); i++ {
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n += len(a[i])
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}
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b := make([]byte, n);
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bp := 0;
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for i := 0; i < len(a); i++ {
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s := a[i];
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for j := 0; j < len(s); j++ {
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b[bp] = s[j];
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bp++
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}
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if i + 1 < len(a) {
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s = sep;
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for j := 0; j < len(s); j++ {
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b[bp] = s[j];
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bp++
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}
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}
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}
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return string(b)
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}
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