1 // Copyright 2016 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.
11 // indexShortStr returns the index of the first instance of sep in s,
12 // or -1 if sep is not present in s.
13 // indexShortStr requires 2 <= len(sep) <= shortStringLen
14 func indexShortStr(s
, sep
string) int // ../runtime/asm_$GOARCH.s
16 // supportsVX reports whether the vector facility is available.
17 // indexShortStr must not be called if the vector facility is not
19 func supportsVX() bool // ../runtime/asm_s390x.s
21 var shortStringLen
= -1
29 // Index returns the index of the first instance of substr in s, or -1 if substr is not present in s.
30 func Index(s
, substr
string) int {
36 return IndexByte(s
, substr
[0])
44 case n
<= shortStringLen
:
45 // Use brute force when s and substr both are small
47 return indexShortStr(s
, substr
)
55 // IndexByte skips 16/32 bytes per iteration,
56 // so it's faster than indexShortStr.
57 o
:= IndexByte(t
[i
:], c
)
63 if s
[i
:i
+n
] == substr
{
68 // Switch to indexShortStr when IndexByte produces too many false positives.
69 // Too many means more that 1 error per 8 characters.
70 // Allow some errors in the beginning.
72 r
:= indexShortStr(s
[i
:], substr
)
81 return indexRabinKarp(s
, substr
)
84 // Count counts the number of non-overlapping instances of substr in s.
85 // If substr is an empty string, Count returns 1 + the number of Unicode code points in s.
86 func Count(s
, substr
string) int {
87 return countGeneric(s
, substr
)