libgo/go/path/filepath/path_windows.go

   1 // Copyright 2010 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package filepath
   6
   7 import (
   8         "strings"
   9 )
  10
  11 func isSlash(c uint8) bool {
  12         return c == '\\' || c == '/'
  13 }
  14
  15 // IsAbs returns true if the path is absolute.
  16 func IsAbs(path string) (b bool) {
  17         v := VolumeName(path)
  18         if v == "" {
  19                 return false
  20         }
  21         path = path[len(v):]
  22         if path == "" {
  23                 return false
  24         }
  25         return isSlash(path[0])
  26 }
  27
  28 // VolumeName returns leading volume name.
  29 // Given "C:\foo\bar" it returns "C:" under windows.
  30 // Given "\\host\share\foo" it returns "\\host\share".
  31 // On other platforms it returns "".
  32 func VolumeName(path string) (v string) {
  33         if len(path) < 2 {
  34                 return ""
  35         }
  36         // with drive letter
  37         c := path[0]
  38         if path[1] == ':' &&
  39                 ('0' <= c && c <= '9' || 'a' <= c && c <= 'z' ||
  40                         'A' <= c && c <= 'Z') {
  41                 return path[:2]
  42         }
  43         // is it UNC
  44         if l := len(path); l >= 5 && isSlash(path[0]) && isSlash(path[1]) &&
  45                 !isSlash(path[2]) && path[2] != '.' {
  46                 // first, leading `\\` and next shouldn't be `\`. its server name.
  47                 for n := 3; n < l-1; n++ {
  48                         // second, next '\' shouldn't be repeated.
  49                         if isSlash(path[n]) {
  50                                 n++
  51                                 // third, following something characters. its share name.
  52                                 if !isSlash(path[n]) {
  53                                         if path[n] == '.' {
  54                                                 break
  55                                         }
  56                                         for ; n < l; n++ {
  57                                                 if isSlash(path[n]) {
  58                                                         break
  59                                                 }
  60                                         }
  61                                         return path[:n]
  62                                 }
  63                                 break
  64                         }
  65                 }
  66         }
  67         return ""
  68 }
  69
  70 // HasPrefix tests whether the path p begins with prefix.
  71 // It ignores case while comparing.
  72 func HasPrefix(p, prefix string) bool {
  73         if strings.HasPrefix(p, prefix) {
  74                 return true
  75         }
  76         return strings.HasPrefix(strings.ToLower(p), strings.ToLower(prefix))
  77 }