mirror of
https://github.com/vbatts/go-mtree.git
synced 2024-12-20 21:06:30 +00:00
102 lines
3 KiB
Go
102 lines
3 KiB
Go
// 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.
|
|
|
|
// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
|
|
|
|
package unix
|
|
|
|
import "unsafe"
|
|
|
|
// readInt returns the size-bytes unsigned integer in native byte order at offset off.
|
|
func readInt(b []byte, off, size uintptr) (u uint64, ok bool) {
|
|
if len(b) < int(off+size) {
|
|
return 0, false
|
|
}
|
|
if isBigEndian {
|
|
return readIntBE(b[off:], size), true
|
|
}
|
|
return readIntLE(b[off:], size), true
|
|
}
|
|
|
|
func readIntBE(b []byte, size uintptr) uint64 {
|
|
switch size {
|
|
case 1:
|
|
return uint64(b[0])
|
|
case 2:
|
|
_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
|
|
return uint64(b[1]) | uint64(b[0])<<8
|
|
case 4:
|
|
_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
|
|
return uint64(b[3]) | uint64(b[2])<<8 | uint64(b[1])<<16 | uint64(b[0])<<24
|
|
case 8:
|
|
_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
|
|
return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
|
|
uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
|
|
default:
|
|
panic("syscall: readInt with unsupported size")
|
|
}
|
|
}
|
|
|
|
func readIntLE(b []byte, size uintptr) uint64 {
|
|
switch size {
|
|
case 1:
|
|
return uint64(b[0])
|
|
case 2:
|
|
_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
|
|
return uint64(b[0]) | uint64(b[1])<<8
|
|
case 4:
|
|
_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
|
|
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24
|
|
case 8:
|
|
_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
|
|
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
|
|
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
|
|
default:
|
|
panic("syscall: readInt with unsupported size")
|
|
}
|
|
}
|
|
|
|
// ParseDirent parses up to max directory entries in buf,
|
|
// appending the names to names. It returns the number of
|
|
// bytes consumed from buf, the number of entries added
|
|
// to names, and the new names slice.
|
|
func ParseDirent(buf []byte, max int, names []string) (consumed int, count int, newnames []string) {
|
|
origlen := len(buf)
|
|
count = 0
|
|
for max != 0 && len(buf) > 0 {
|
|
reclen, ok := direntReclen(buf)
|
|
if !ok || reclen > uint64(len(buf)) {
|
|
return origlen, count, names
|
|
}
|
|
rec := buf[:reclen]
|
|
buf = buf[reclen:]
|
|
ino, ok := direntIno(rec)
|
|
if !ok {
|
|
break
|
|
}
|
|
if ino == 0 { // File absent in directory.
|
|
continue
|
|
}
|
|
const namoff = uint64(unsafe.Offsetof(Dirent{}.Name))
|
|
namlen, ok := direntNamlen(rec)
|
|
if !ok || namoff+namlen > uint64(len(rec)) {
|
|
break
|
|
}
|
|
name := rec[namoff : namoff+namlen]
|
|
for i, c := range name {
|
|
if c == 0 {
|
|
name = name[:i]
|
|
break
|
|
}
|
|
}
|
|
// Check for useless names before allocating a string.
|
|
if string(name) == "." || string(name) == ".." {
|
|
continue
|
|
}
|
|
max--
|
|
count++
|
|
names = append(names, string(name))
|
|
}
|
|
return origlen - len(buf), count, names
|
|
}
|