mirror of git://gcc.gnu.org/git/gcc.git
62 lines
1.3 KiB
Go
62 lines
1.3 KiB
Go
// Copyright 2015 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.
|
|
|
|
// -build !amd64,!s390x
|
|
|
|
package strings
|
|
|
|
// TODO: implements short string optimization on non amd64 platforms
|
|
// and get rid of strings_amd64.go
|
|
|
|
// Index returns the index of the first instance of substr in s, or -1 if substr is not present in s.
|
|
func Index(s, substr string) int {
|
|
n := len(substr)
|
|
switch {
|
|
case n == 0:
|
|
return 0
|
|
case n == 1:
|
|
return IndexByte(s, substr[0])
|
|
case n == len(s):
|
|
if substr == s {
|
|
return 0
|
|
}
|
|
return -1
|
|
case n > len(s):
|
|
return -1
|
|
}
|
|
c := substr[0]
|
|
i := 0
|
|
t := s[:len(s)-n+1]
|
|
fails := 0
|
|
for i < len(t) {
|
|
if t[i] != c {
|
|
o := IndexByte(t[i:], c)
|
|
if o < 0 {
|
|
return -1
|
|
}
|
|
i += o
|
|
}
|
|
if s[i:i+n] == substr {
|
|
return i
|
|
}
|
|
i++
|
|
fails++
|
|
if fails >= 4+i>>4 && i < len(t) {
|
|
// See comment in ../bytes/bytes_generic.go.
|
|
j := indexRabinKarp(s[i:], substr)
|
|
if j < 0 {
|
|
return -1
|
|
}
|
|
return i + j
|
|
}
|
|
}
|
|
return -1
|
|
}
|
|
|
|
// Count counts the number of non-overlapping instances of substr in s.
|
|
// If substr is an empty string, Count returns 1 + the number of Unicode code points in s.
|
|
func Count(s, substr string) int {
|
|
return countGeneric(s, substr)
|
|
}
|