c2047754c3
Compiler changes:
* Change map assignment to use mapassign and assign value directly.
* Change string iteration to use decoderune, faster for ASCII strings.
* Change makeslice to take int, and use makeslice64 for larger values.
* Add new noverflow field to hmap struct used for maps.
Unresolved problems, to be fixed later:
* Commented out test in go/types/sizes_test.go that doesn't compile.
* Commented out reflect.TestStructOf test for padding after zero-sized field.
Reviewed-on: https://go-review.googlesource.com/35231
gotools/:
Updates for Go 1.8rc1.
* Makefile.am (go_cmd_go_files): Add bug.go.
(s-zdefaultcc): Write defaultPkgConfig.
* Makefile.in: Rebuild.
From-SVN: r244456
101 lines
2.1 KiB
Go
101 lines
2.1 KiB
Go
// Copyright 2016 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 ignore
|
|
|
|
package strings
|
|
|
|
//go:noescape
|
|
|
|
// indexShortStr returns the index of the first instance of sep in s,
|
|
// or -1 if sep is not present in s.
|
|
// indexShortStr requires 2 <= len(sep) <= shortStringLen
|
|
func indexShortStr(s, sep string) int // ../runtime/asm_$GOARCH.s
|
|
|
|
// supportsVX reports whether the vector facility is available.
|
|
// indexShortStr must not be called if the vector facility is not
|
|
// available.
|
|
func supportsVX() bool // ../runtime/asm_s390x.s
|
|
|
|
var shortStringLen = -1
|
|
|
|
func init() {
|
|
if supportsVX() {
|
|
shortStringLen = 64
|
|
}
|
|
}
|
|
|
|
// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
|
|
func Index(s, sep string) int {
|
|
n := len(sep)
|
|
switch {
|
|
case n == 0:
|
|
return 0
|
|
case n == 1:
|
|
return IndexByte(s, sep[0])
|
|
case n == len(s):
|
|
if sep == s {
|
|
return 0
|
|
}
|
|
return -1
|
|
case n > len(s):
|
|
return -1
|
|
case n <= shortStringLen:
|
|
// Use brute force when s and sep both are small
|
|
if len(s) <= 64 {
|
|
return indexShortStr(s, sep)
|
|
}
|
|
c := sep[0]
|
|
i := 0
|
|
t := s[:len(s)-n+1]
|
|
fails := 0
|
|
for i < len(t) {
|
|
if t[i] != c {
|
|
// IndexByte skips 16/32 bytes per iteration,
|
|
// so it's faster than indexShortStr.
|
|
o := IndexByte(t[i:], c)
|
|
if o < 0 {
|
|
return -1
|
|
}
|
|
i += o
|
|
}
|
|
if s[i:i+n] == sep {
|
|
return i
|
|
}
|
|
fails++
|
|
i++
|
|
// Switch to indexShortStr when IndexByte produces too many false positives.
|
|
// Too many means more that 1 error per 8 characters.
|
|
// Allow some errors in the beginning.
|
|
if fails > (i+16)/8 {
|
|
r := indexShortStr(s[i:], sep)
|
|
if r >= 0 {
|
|
return r + i
|
|
}
|
|
return -1
|
|
}
|
|
}
|
|
return -1
|
|
}
|
|
// Rabin-Karp search
|
|
hashsep, pow := hashStr(sep)
|
|
var h uint32
|
|
for i := 0; i < n; i++ {
|
|
h = h*primeRK + uint32(s[i])
|
|
}
|
|
if h == hashsep && s[:n] == sep {
|
|
return 0
|
|
}
|
|
for i := n; i < len(s); {
|
|
h *= primeRK
|
|
h += uint32(s[i])
|
|
h -= pow * uint32(s[i-n])
|
|
i++
|
|
if h == hashsep && s[i-n:i] == sep {
|
|
return i - n
|
|
}
|
|
}
|
|
return -1
|
|
}
|