ShellPkg/Library/BasePathLib/BasePathLib.c

   1 /** @file
   2   Provides interface to path manipulation functions.
   3
   4   Copyright (c) 2011, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12 **/
  13
  14 #include <Base.h>
  15 #include <Library/BaseMemoryLib.h>
  16 #include <Library/PathLib.h>
  17 #include <Library/BaseLib.h>
  18
  19 /**
  20   Removes the last directory or file entry in a path by changing the last
  21   L'\' to a CHAR_NULL.
  22
  23   @param[in, out] Path    The pointer to the path to modify.
  24
  25   @retval FALSE     Nothing was found to remove.
  26   @retval TRUE      A directory or file was removed.
  27 **/
  28 BOOLEAN
  29 EFIAPI
  30 PathRemoveLastItem(
  31   IN OUT CHAR16 *Path
  32   )
  33 {
  34   CHAR16        *Walker;
  35   CHAR16        *LastSlash;
  36   //
  37   // get directory name from path... ('chop' off extra)
  38   //
  39   for ( Walker = Path, LastSlash = NULL
  40       ; Walker != NULL && *Walker != CHAR_NULL
  41       ; Walker++
  42      ){
  43     if (*Walker == L'\\' && *(Walker + 1) != CHAR_NULL) {
  44       LastSlash = Walker+1;
  45     }
  46   }
  47   if (LastSlash != NULL) {
  48     *LastSlash = CHAR_NULL;
  49     return (TRUE);
  50   }
  51   return (FALSE);
  52 }
  53
  54 /**
  55   Function to clean up paths.
  56
  57   - Single periods in the path are removed.
  58   - Double periods in the path are removed along with a single parent directory.
  59   - Forward slashes L'/' are converted to backward slashes L'\'.
  60
  61   This will be done inline and the existing buffer may be larger than required
  62   upon completion.
  63
  64   @param[in] Path       The pointer to the string containing the path.
  65
  66   @retval NULL          An error occured.
  67   @return Path in all other instances.
  68 **/
  69 CHAR16*
  70 EFIAPI
  71 PathCleanUpDirectories(
  72   IN CHAR16 *Path
  73   )
  74 {
  75   CHAR16  *TempString;
  76   UINTN   TempSize;
  77   if (Path==NULL) {
  78     return(NULL);
  79   }
  80
  81   //
  82   // Fix up the '/' vs '\'
  83   //
  84   for (TempString = Path ; TempString != NULL && *TempString != CHAR_NULL ; TempString++) {
  85     if (*TempString == L'/') {
  86       *TempString = L'\\';
  87     }
  88   }
  89
  90   //
  91   // Fix up the ..
  92   //
  93   while ((TempString = StrStr(Path, L"\\..\\")) != NULL) {
  94     *TempString = CHAR_NULL;
  95     TempString  += 4;
  96     PathRemoveLastItem(Path);
  97     TempSize = StrSize(TempString);
  98     CopyMem(Path+StrLen(Path), TempString, TempSize);
  99   }
 100   if ((TempString = StrStr(Path, L"\\..")) != NULL && *(TempString + 3) == CHAR_NULL) {
 101     *TempString = CHAR_NULL;
 102     PathRemoveLastItem(Path);
 103   }
 104
 105   //
 106   // Fix up the .
 107   //
 108   while ((TempString = StrStr(Path, L"\\.\\")) != NULL) {
 109     *TempString = CHAR_NULL;
 110     TempString  += 2;
 111     TempSize = StrSize(TempString);
 112     CopyMem(Path+StrLen(Path), TempString, TempSize);
 113   }
 114   if ((TempString = StrStr(Path, L"\\.")) != NULL && *(TempString + 2) == CHAR_NULL) {
 115     *TempString = CHAR_NULL;
 116   }
 117
 118
 119
 120   return (Path);
 121 }
 122