all: add internal/itoa package

This replaces five implementations scattered across low level packages.
(And I plan to use it in a sixth soon.)
Three of the five were byte-for-byte identical.

Change-Id: I3bbbeeac63723a487986c912b604e10ad1e042f4
Reviewed-on: https://go-review.googlesource.com/c/go/+/301549
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>

10 files changed, 23 insertions, 62 deletions

diff --git a/src/syscall/dll_windows.go b/src/syscall/dll_windows.go
index d99da00089..16210ca5b5 100644
--- a/src/syscall/dll_windows.go
+++ b/src/syscall/dll_windows.go
@@ -5,6 +5,7 @@
 package syscall
 
 import (
+	"internal/itoa"
 	"internal/syscall/windows/sysdll"
 	"sync"
 	"sync/atomic"
@@ -215,7 +216,7 @@ func (p *Proc) Call(a ...uintptr) (r1, r2 uintptr, lastErr error) {
 	case 18:
 		return Syscall18(p.Addr(), uintptr(len(a)), a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7], a[8], a[9], a[10], a[11], a[12], a[13], a[14], a[15], a[16], a[17])
 	default:
-		panic("Call " + p.Name + " with too many arguments " + itoa(len(a)) + ".")
+		panic("Call " + p.Name + " with too many arguments " + itoa.Itoa(len(a)) + ".")
 	}
 }
 
diff --git a/src/syscall/exec_linux.go b/src/syscall/exec_linux.go
index 6353da4048..deb8aa38b7 100644
--- a/src/syscall/exec_linux.go
+++ b/src/syscall/exec_linux.go
@@ -8,6 +8,7 @@
 package syscall
 
 import (
+	"internal/itoa"
 	"runtime"
 	"unsafe"
 )
@@ -568,7 +569,7 @@ func forkExecPipe(p []int) (err error) {
 func formatIDMappings(idMap []SysProcIDMap) []byte {
 	var data []byte
 	for _, im := range idMap {
-		data = append(data, []byte(itoa(im.ContainerID)+" "+itoa(im.HostID)+" "+itoa(im.Size)+"\n")...)
+		data = append(data, []byte(itoa.Itoa(im.ContainerID)+" "+itoa.Itoa(im.HostID)+" "+itoa.Itoa(im.Size)+"\n")...)
 	}
 	return data
 }
@@ -597,7 +598,7 @@ func writeIDMappings(path string, idMap []SysProcIDMap) error {
 // This is needed since kernel 3.19, because you can't write gid_map without
 // disabling setgroups() system call.
 func writeSetgroups(pid int, enable bool) error {
-	sgf := "/proc/" + itoa(pid) + "/setgroups"
+	sgf := "/proc/" + itoa.Itoa(pid) + "/setgroups"
 	fd, err := Open(sgf, O_RDWR, 0)
 	if err != nil {
 		return err
@@ -622,7 +623,7 @@ func writeSetgroups(pid int, enable bool) error {
 // for a process and it is called from the parent process.
 func writeUidGidMappings(pid int, sys *SysProcAttr) error {
 	if sys.UidMappings != nil {
-		uidf := "/proc/" + itoa(pid) + "/uid_map"
+		uidf := "/proc/" + itoa.Itoa(pid) + "/uid_map"
 		if err := writeIDMappings(uidf, sys.UidMappings); err != nil {
 			return err
 		}
@@ -633,7 +634,7 @@ func writeUidGidMappings(pid int, sys *SysProcAttr) error {
 		if err := writeSetgroups(pid, sys.GidMappingsEnableSetgroups); err != nil && err != ENOENT {
 			return err
 		}
-		gidf := "/proc/" + itoa(pid) + "/gid_map"
+		gidf := "/proc/" + itoa.Itoa(pid) + "/gid_map"
 		if err := writeIDMappings(gidf, sys.GidMappings); err != nil {
 			return err
 		}
diff --git a/src/syscall/exec_plan9.go b/src/syscall/exec_plan9.go
index 12c4237f69..c469fe1812 100644
--- a/src/syscall/exec_plan9.go
+++ b/src/syscall/exec_plan9.go
@@ -7,6 +7,7 @@
 package syscall
 
 import (
+	"internal/itoa"
 	"runtime"
 	"sync"
 	"unsafe"
@@ -320,7 +321,7 @@ func cexecPipe(p []int) error {
 		return e
 	}
 
-	fd, e := Open("#d/"+itoa(p[1]), O_RDWR|O_CLOEXEC)
+	fd, e := Open("#d/"+itoa.Itoa(p[1]), O_RDWR|O_CLOEXEC)
 	if e != nil {
 		Close(p[0])
 		Close(p[1])
diff --git a/src/syscall/export_test.go b/src/syscall/export_test.go
deleted file mode 100644
index 55c09e667e..0000000000
--- a/src/syscall/export_test.go
+++ /dev/null
@@ -1,7 +0,0 @@
-// 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 syscall
-
-var Itoa = itoa
diff --git a/src/syscall/str.go b/src/syscall/str.go
deleted file mode 100644
index 2ddf04b227..0000000000
--- a/src/syscall/str.go
+++ /dev/null
@@ -1,24 +0,0 @@
-// Copyright 2009 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 syscall
-
-func itoa(val int) string { // do it here rather than with fmt to avoid dependency
-	if val < 0 {
-		return "-" + uitoa(uint(-val))
-	}
-	return uitoa(uint(val))
-}
-
-func uitoa(val uint) string {
-	var buf [32]byte // big enough for int64
-	i := len(buf) - 1
-	for val >= 10 {
-		buf[i] = byte(val%10 + '0')
-		i--
-		val /= 10
-	}
-	buf[i] = byte(val + '0')
-	return string(buf[i:])
-}
diff --git a/src/syscall/syscall_js.go b/src/syscall/syscall_js.go
index c17c6fcdcf..ed70d62284 100644
--- a/src/syscall/syscall_js.go
+++ b/src/syscall/syscall_js.go
@@ -8,6 +8,7 @@
 package syscall
 
 import (
+	"internal/itoa"
 	"internal/oserror"
 	"sync"
 	"unsafe"
@@ -60,7 +61,7 @@ func (e Errno) Error() string {
 			return s
 		}
 	}
-	return "errno " + itoa(int(e))
+	return "errno " + itoa.Itoa(int(e))
 }
 
 func (e Errno) Is(target error) bool {
@@ -106,7 +107,7 @@ func (s Signal) String() string {
 			return str
 		}
 	}
-	return "signal " + itoa(int(s))
+	return "signal " + itoa.Itoa(int(s))
 }
 
 var signals = [...]string{}
diff --git a/src/syscall/syscall_linux.go b/src/syscall/syscall_linux.go
index 3041f6f8fc..24e051dcbd 100644
--- a/src/syscall/syscall_linux.go
+++ b/src/syscall/syscall_linux.go
@@ -11,7 +11,10 @@
 
 package syscall
 
-import "unsafe"
+import (
+	"internal/itoa"
+	"unsafe"
+)
 
 func rawSyscallNoError(trap, a1, a2, a3 uintptr) (r1, r2 uintptr)
 
@@ -225,7 +228,7 @@ func Futimesat(dirfd int, path string, tv []Timeval) (err error) {
 func Futimes(fd int, tv []Timeval) (err error) {
 	// Believe it or not, this is the best we can do on Linux
 	// (and is what glibc does).
-	return Utimes("/proc/self/fd/"+itoa(fd), tv)
+	return Utimes("/proc/self/fd/"+itoa.Itoa(fd), tv)
 }
 
 const ImplementsGetwd = true
diff --git a/src/syscall/syscall_test.go b/src/syscall/syscall_test.go
index 5390f8aace..b2b9463b0f 100644
--- a/src/syscall/syscall_test.go
+++ b/src/syscall/syscall_test.go
@@ -5,7 +5,6 @@
 package syscall_test
 
 import (
-	"fmt"
 	"internal/testenv"
 	"os"
 	"runtime"
@@ -33,22 +32,6 @@ func TestEnv(t *testing.T) {
 	testSetGetenv(t, "TESTENV", "")
 }
 
-func TestItoa(t *testing.T) {
-	// Make most negative integer: 0x8000...
-	i := 1
-	for i<<1 != 0 {
-		i <<= 1
-	}
-	if i >= 0 {
-		t.Fatal("bad math")
-	}
-	s := syscall.Itoa(i)
-	f := fmt.Sprint(i)
-	if s != f {
-		t.Fatalf("itoa(%d) = %s, want %s", i, s, f)
-	}
-}
-
 // Check that permuting child process fds doesn't interfere with
 // reporting of fork/exec status. See Issue 14979.
 func TestExecErrPermutedFds(t *testing.T) {
diff --git a/src/syscall/syscall_unix.go b/src/syscall/syscall_unix.go
index 40fc8b8a30..5b405b99b4 100644
--- a/src/syscall/syscall_unix.go
+++ b/src/syscall/syscall_unix.go
@@ -8,6 +8,7 @@
 package syscall
 
 import (
+	"internal/itoa"
 	"internal/oserror"
 	"internal/race"
 	"internal/unsafeheader"
@@ -121,7 +122,7 @@ func (e Errno) Error() string {
 			return s
 		}
 	}
-	return "errno " + itoa(int(e))
+	return "errno " + itoa.Itoa(int(e))
 }
 
 func (e Errno) Is(target error) bool {
@@ -181,7 +182,7 @@ func (s Signal) String() string {
 			return str
 		}
 	}
-	return "signal " + itoa(int(s))
+	return "signal " + itoa.Itoa(int(s))
 }
 
 func Read(fd int, p []byte) (n int, err error) {
diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index 65af6637ae..f9f78bd2b3 100644
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -8,6 +8,7 @@ package syscall
 
 import (
 	errorspkg "errors"
+	"internal/itoa"
 	"internal/oserror"
 	"internal/race"
 	"internal/unsafeheader"
@@ -132,7 +133,7 @@ func (e Errno) Error() string {
 	if err != nil {
 		n, err = formatMessage(flags, 0, uint32(e), 0, b, nil)
 		if err != nil {
-			return "winapi error #" + itoa(int(e))
+			return "winapi error #" + itoa.Itoa(int(e))
 		}
 	}
 	// trim terminating \r and \n
@@ -1152,7 +1153,7 @@ func (s Signal) String() string {
 			return str
 		}
 	}
-	return "signal " + itoa(int(s))
+	return "signal " + itoa.Itoa(int(s))
 }
 
 func LoadCreateSymbolicLink() error {