mirror of
https://github.com/golang/go
synced 2024-11-20 08:04:42 -07:00
0c3c2c1724
float.c held bit patterns for special float64 values, hiding from the real uses. Rewrite Go code not to refer to those values directly. Convert library routines in runtime.c and string.c. LGTM=r R=r, dave CC=austin, dvyukov, golang-codereviews, iant, khr https://golang.org/cl/170330043
109 lines
1.8 KiB
Go
109 lines
1.8 KiB
Go
// Copyright 2009 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 "unsafe"
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//go:nosplit
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func findnull(s *byte) int {
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if s == nil {
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return 0
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}
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p := (*[_MaxMem/2 - 1]byte)(unsafe.Pointer(s))
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l := 0
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for p[l] != 0 {
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l++
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}
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return l
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}
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func findnullw(s *uint16) int {
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if s == nil {
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return 0
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}
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p := (*[_MaxMem/2/2 - 1]uint16)(unsafe.Pointer(s))
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l := 0
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for p[l] != 0 {
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l++
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}
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return l
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}
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var maxstring uintptr = 256 // a hint for print
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//go:nosplit
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func gostringnocopy(str *byte) string {
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var s string
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sp := (*stringStruct)(unsafe.Pointer(&s))
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sp.str = unsafe.Pointer(str)
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sp.len = findnull(str)
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for {
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ms := maxstring
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if uintptr(len(s)) <= ms || casuintptr(&maxstring, ms, uintptr(len(s))) {
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break
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}
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}
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return s
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}
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func gostringw(strw *uint16) string {
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var buf [8]byte
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str := (*[_MaxMem/2/2 - 1]uint16)(unsafe.Pointer(strw))
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n1 := 0
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for i := 0; str[i] != 0; i++ {
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n1 += runetochar(buf[:], rune(str[i]))
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}
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s, b := rawstring(n1 + 4)
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n2 := 0
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for i := 0; str[i] != 0; i++ {
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// check for race
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if n2 >= n1 {
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break
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}
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n2 += runetochar(b[n2:], rune(str[i]))
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}
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b[n2] = 0 // for luck
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return s[:n2]
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}
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func strcmp(s1, s2 *byte) int32 {
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p1 := (*[_MaxMem/2 - 1]byte)(unsafe.Pointer(s1))
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p2 := (*[_MaxMem/2 - 1]byte)(unsafe.Pointer(s2))
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for i := uintptr(0); ; i++ {
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c1 := p1[i]
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c2 := p2[i]
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if c1 < c2 {
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return -1
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}
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if c1 > c2 {
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return +1
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}
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if c1 == 0 {
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return 0
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}
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}
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}
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func strncmp(s1, s2 *byte, n uintptr) int32 {
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p1 := (*[_MaxMem/2 - 1]byte)(unsafe.Pointer(s1))
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p2 := (*[_MaxMem/2 - 1]byte)(unsafe.Pointer(s2))
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for i := uintptr(0); i < n; i++ {
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c1 := p1[i]
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c2 := p2[i]
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if c1 < c2 {
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return -1
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}
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if c1 > c2 {
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return +1
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}
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if c1 == 0 {
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break
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}
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}
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return 0
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}
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