mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-12 11:29:30 +00:00
299 lines
6.0 KiB
Go
299 lines
6.0 KiB
Go
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// Copyright 2014 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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package runtime
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import (
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"unsafe"
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)
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func concatstrings(a []string) string {
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idx := 0
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l := 0
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count := 0
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for i, x := range a {
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n := len(x)
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if n == 0 {
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continue
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}
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if l+n < l {
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gothrow("string concatenation too long")
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}
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l += n
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count++
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idx = i
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}
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if count == 0 {
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return ""
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}
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if count == 1 {
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return a[idx]
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}
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s, b := rawstring(l)
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l = 0
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for _, x := range a {
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copy(b[l:], x)
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l += len(x)
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}
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return s
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}
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//go:nosplit
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func concatstring2(a [2]string) string {
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return concatstrings(a[:])
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}
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//go:nosplit
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func concatstring3(a [3]string) string {
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return concatstrings(a[:])
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}
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//go:nosplit
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func concatstring4(a [4]string) string {
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return concatstrings(a[:])
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}
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//go:nosplit
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func concatstring5(a [5]string) string {
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return concatstrings(a[:])
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}
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func slicebytetostring(b []byte) string {
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if raceenabled && len(b) > 0 {
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racereadrangepc(unsafe.Pointer(&b[0]),
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uintptr(len(b)),
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getcallerpc(unsafe.Pointer(&b)),
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funcPC(slicebytetostring))
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}
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s, c := rawstring(len(b))
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copy(c, b)
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return s
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}
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func slicebytetostringtmp(b []byte) string {
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// Return a "string" referring to the actual []byte bytes.
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// This is only for use by internal compiler optimizations
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// that know that the string form will be discarded before
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// the calling goroutine could possibly modify the original
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// slice or synchronize with another goroutine.
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// Today, the only such case is a m[string(k)] lookup where
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// m is a string-keyed map and k is a []byte.
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if raceenabled && len(b) > 0 {
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racereadrangepc(unsafe.Pointer(&b[0]),
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uintptr(len(b)),
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getcallerpc(unsafe.Pointer(&b)),
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funcPC(slicebytetostringtmp))
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}
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return *(*string)(unsafe.Pointer(&b))
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}
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func stringtoslicebyte(s string) []byte {
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b := rawbyteslice(len(s))
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copy(b, s)
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return b
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}
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func stringtoslicerune(s string) []rune {
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// two passes.
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// unlike slicerunetostring, no race because strings are immutable.
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n := 0
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t := s
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for len(s) > 0 {
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_, k := charntorune(s)
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s = s[k:]
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n++
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}
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a := rawruneslice(n)
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n = 0
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for len(t) > 0 {
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r, k := charntorune(t)
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t = t[k:]
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a[n] = r
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n++
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}
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return a
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}
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func slicerunetostring(a []rune) string {
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if raceenabled && len(a) > 0 {
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racereadrangepc(unsafe.Pointer(&a[0]),
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uintptr(len(a))*unsafe.Sizeof(a[0]),
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getcallerpc(unsafe.Pointer(&a)),
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funcPC(slicerunetostring))
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}
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var dum [4]byte
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size1 := 0
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for _, r := range a {
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size1 += runetochar(dum[:], r)
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}
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s, b := rawstring(size1 + 3)
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size2 := 0
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for _, r := range a {
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// check for race
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if size2 >= size1 {
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break
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}
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size2 += runetochar(b[size2:], r)
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}
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return s[:size2]
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}
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type stringStruct struct {
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str unsafe.Pointer
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len int
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}
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func intstring(v int64) string {
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s, b := rawstring(4)
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n := runetochar(b, rune(v))
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return s[:n]
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}
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// stringiter returns the index of the next
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// rune after the rune that starts at s[k].
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func stringiter(s string, k int) int {
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if k >= len(s) {
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// 0 is end of iteration
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return 0
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}
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c := s[k]
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if c < runeself {
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return k + 1
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}
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// multi-char rune
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_, n := charntorune(s[k:])
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return k + n
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}
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// stringiter2 returns the rune that starts at s[k]
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// and the index where the next rune starts.
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func stringiter2(s string, k int) (int, rune) {
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if k >= len(s) {
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// 0 is end of iteration
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return 0, 0
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}
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c := s[k]
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if c < runeself {
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return k + 1, rune(c)
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}
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// multi-char rune
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r, n := charntorune(s[k:])
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return k + n, r
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}
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// rawstring allocates storage for a new string. The returned
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// string and byte slice both refer to the same storage.
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// The storage is not zeroed. Callers should use
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// b to set the string contents and then drop b.
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func rawstring(size int) (s string, b []byte) {
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p := mallocgc(uintptr(size), nil, flagNoScan|flagNoZero)
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(*stringStruct)(unsafe.Pointer(&s)).str = p
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(*stringStruct)(unsafe.Pointer(&s)).len = size
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(*slice)(unsafe.Pointer(&b)).array = (*uint8)(p)
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(*slice)(unsafe.Pointer(&b)).len = uint(size)
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(*slice)(unsafe.Pointer(&b)).cap = uint(size)
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for {
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ms := maxstring
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if uintptr(size) <= uintptr(ms) || casuintptr((*uintptr)(unsafe.Pointer(&maxstring)), uintptr(ms), uintptr(size)) {
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return
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}
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}
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}
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// rawbyteslice allocates a new byte slice. The byte slice is not zeroed.
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func rawbyteslice(size int) (b []byte) {
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cap := goroundupsize(uintptr(size))
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p := mallocgc(cap, nil, flagNoScan|flagNoZero)
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if cap != uintptr(size) {
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memclr(add(p, uintptr(size)), cap-uintptr(size))
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}
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(*slice)(unsafe.Pointer(&b)).array = (*uint8)(p)
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(*slice)(unsafe.Pointer(&b)).len = uint(size)
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(*slice)(unsafe.Pointer(&b)).cap = uint(cap)
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return
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}
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// rawruneslice allocates a new rune slice. The rune slice is not zeroed.
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func rawruneslice(size int) (b []rune) {
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if uintptr(size) > maxmem/4 {
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gothrow("out of memory")
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}
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mem := goroundupsize(uintptr(size) * 4)
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p := mallocgc(mem, nil, flagNoScan|flagNoZero)
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if mem != uintptr(size)*4 {
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memclr(add(p, uintptr(size)*4), mem-uintptr(size)*4)
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}
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(*slice)(unsafe.Pointer(&b)).array = (*uint8)(p)
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(*slice)(unsafe.Pointer(&b)).len = uint(size)
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(*slice)(unsafe.Pointer(&b)).cap = uint(mem / 4)
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return
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}
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// used by cmd/cgo
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func gobytes(p *byte, n int) []byte {
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if n == 0 {
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return make([]byte, 0)
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}
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x := make([]byte, n)
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memmove(unsafe.Pointer(&x[0]), unsafe.Pointer(p), uintptr(n))
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return x
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}
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func gostringsize(n int) string {
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s, _ := rawstring(n)
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return s
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}
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//go:noescape
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func findnull(*byte) int
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func gostring(p *byte) string {
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l := findnull(p)
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if l == 0 {
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return ""
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}
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s, b := rawstring(l)
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memmove(unsafe.Pointer(&b[0]), unsafe.Pointer(p), uintptr(l))
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return s
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}
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func gostringn(p *byte, l int) string {
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if l == 0 {
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return ""
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}
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s, b := rawstring(l)
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memmove(unsafe.Pointer(&b[0]), unsafe.Pointer(p), uintptr(l))
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return s
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}
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func index(s, t string) int {
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if len(t) == 0 {
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return 0
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}
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for i := 0; i < len(s); i++ {
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if s[i] == t[0] && hasprefix(s[i:], t) {
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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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func contains(s, t string) bool {
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return index(s, t) >= 0
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}
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func hasprefix(s, t string) bool {
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return len(s) >= len(t) && s[:len(t)] == t
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}
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