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// Copyright 2014 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.
package runtime
import (
"unsafe"
)
func concatstrings(a []string) string {
idx := 0
l := 0
count := 0
for i, x := range a {
n := len(x)
if n == 0 {
continue
}
if l+n < l {
panic("string concatenation too long")
}
l += n
count++
idx = i
}
if count == 0 {
return ""
}
if count == 1 {
return a[idx]
}
s, b := rawstring(l)
l = 0
for _, x := range a {
copy(b[l:], x)
l += len(x)
}
return s
}
//go:nosplit
func concatstring2(a [2]string) string {
return concatstrings(a[:])
}
//go:nosplit
func concatstring3(a [3]string) string {
return concatstrings(a[:])
}
//go:nosplit
func concatstring4(a [4]string) string {
return concatstrings(a[:])
}
//go:nosplit
func concatstring5(a [5]string) string {
return concatstrings(a[:])
}
func slicebytetostring(b []byte) string {
if raceenabled && len(b) > 0 {
fn := slicebytetostring
racereadrangepc(unsafe.Pointer(&b[0]),
len(b),
gogetcallerpc(unsafe.Pointer(&b)),
**(**uintptr)(unsafe.Pointer(&fn)))
}
s, c := rawstring(len(b))
copy(c, b)
return s
}
func slicebytetostringtmp(b []byte) string {
// Return a "string" referring to the actual []byte bytes.
// This is only for use by internal compiler optimizations
// that know that the string form will be discarded before
// the calling goroutine could possibly modify the original
// slice or synchronize with another goroutine.
// Today, the only such case is a m[string(k)] lookup where
// m is a string-keyed map and k is a []byte.
if raceenabled && len(b) > 0 {
fn := slicebytetostringtmp
racereadrangepc(unsafe.Pointer(&b[0]),
len(b),
gogetcallerpc(unsafe.Pointer(&b)),
**(**uintptr)(unsafe.Pointer(&fn)))
}
return *(*string)(unsafe.Pointer(&b))
}
func stringtoslicebyte(s string) []byte {
b := rawbyteslice(len(s))
copy(b, s)
return b
}
func stringtoslicerune(s string) []rune {
// two passes.
// unlike slicerunetostring, no race because strings are immutable.
n := 0
t := s
for len(s) > 0 {
_, k := charntorune(s)
s = s[k:]
n++
}
a := rawruneslice(n)
n = 0
for len(t) > 0 {
r, k := charntorune(t)
t = t[k:]
a[n] = r
n++
}
return a
}
func slicerunetostring(a []rune) string {
if raceenabled && len(a) > 0 {
fn := slicerunetostring
racereadrangepc(unsafe.Pointer(&a[0]),
len(a)*int(unsafe.Sizeof(a[0])),
gogetcallerpc(unsafe.Pointer(&a)),
**(**uintptr)(unsafe.Pointer(&fn)))
}
var dum [4]byte
size1 := 0
for _, r := range a {
size1 += runetochar(dum[:], r)
}
s, b := rawstring(size1 + 3)
size2 := 0
for _, r := range a {
// check for race
if size2 >= size1 {
break
}
size2 += runetochar(b[size2:], r)
}
return s[:size2]
}
type stringStruct struct {
str unsafe.Pointer
len int
}
func cstringToGo(str uintptr) (s string) {
i := 0
for ; ; i++ {
if *(*byte)(unsafe.Pointer(str + uintptr(i))) == 0 {
break
}
}
t := (*stringStruct)(unsafe.Pointer(&s))
t.str = unsafe.Pointer(str)
t.len = i
return
}
func intstring(v int64) string {
s, b := rawstring(4)
n := runetochar(b, rune(v))
return s[:n]
}
// stringiter returns the index of the next
// rune after the rune that starts at s[k].
func stringiter(s string, k int) int {
if k >= len(s) {
// 0 is end of iteration
return 0
}
c := s[k]
if c < runeself {
return k + 1
}
// multi-char rune
_, n := charntorune(s[k:])
return k + n
}
// stringiter2 returns the rune that starts at s[k]
// and the index where the next rune starts.
func stringiter2(s string, k int) (int, rune) {
if k >= len(s) {
// 0 is end of iteration
return 0, 0
}
c := s[k]
if c < runeself {
return k + 1, rune(c)
}
// multi-char rune
r, n := charntorune(s[k:])
return k + n, r
}
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