MdePkg/Library/BaseLib/FilePaths.c

   1 /** @file
   2   Defines file-path manipulation functions.
   3
   4   Copyright (c) 2011 - 2016, 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 #include  <Library/BaseMemoryLib.h>
  14 #include  <Library/BaseLib.h>
  15
  16 /**
  17   Removes the last directory or file entry in a path. For a path which is
  18   like L"fs0:startup.nsh", it's converted to L"fs0:".
  19
  20   @param[in,out] Path     A pointer to the path to modify.
  21
  22   @retval FALSE     Nothing was found to remove.
  23   @retval TRUE      A directory or file was removed.
  24 **/
  25 BOOLEAN
  26 EFIAPI
  27 PathRemoveLastItem(
  28   IN OUT CHAR16 *Path
  29   )
  30 {
  31   CHAR16        *Walker;
  32   CHAR16        *LastSlash;
  33   //
  34   // get directory name from path... ('chop' off extra)
  35   //
  36   for ( Walker = Path, LastSlash = NULL
  37       ; Walker != NULL && *Walker != CHAR_NULL
  38       ; Walker++
  39      ){
  40     if (*Walker == L'\\' && *(Walker + 1) != CHAR_NULL) {
  41       LastSlash = Walker+1;
  42     } else if (*Walker == L':' && *(Walker + 1) != L'\\' && *(Walker + 1) != CHAR_NULL) {
  43       LastSlash = Walker+1;
  44     }
  45   }
  46   if (LastSlash != NULL) {
  47     *LastSlash = CHAR_NULL;
  48     return (TRUE);
  49   }
  50   return (FALSE);
  51 }
  52
  53 /**
  54   Function to clean up paths.
  55
  56   - Single periods in the path are removed.
  57   - Double periods in the path are removed along with a single parent directory.
  58   - Forward slashes L'/' are converted to backward slashes L'\'.
  59
  60   This will be done inline and the existing buffer may be larger than required
  61   upon completion.
  62
  63   @param[in] Path       The pointer to the string containing the path.
  64
  65   @return       Returns Path, otherwise returns NULL to indicate that an error has occured.
  66 **/
  67 CHAR16*
  68 EFIAPI
  69 PathCleanUpDirectories(
  70   IN CHAR16 *Path
  71   )
  72 {
  73   CHAR16  *TempString;
  74   UINTN   TempSize;
  75
  76   if (Path==NULL) {
  77     return(NULL);
  78   }
  79   //
  80   // Fix up the '/' vs '\'
  81   //
  82   for (TempString = Path ; TempString != NULL && *TempString != CHAR_NULL ; TempString++) {
  83     if (*TempString == L'/') {
  84       *TempString = L'\\';
  85     }
  86   }
  87   //
  88   // Fix up the ..
  89   //
  90   while ((TempString = StrStr(Path, L"\\..\\")) != NULL) {
  91     *TempString = CHAR_NULL;
  92     TempString  += 4;
  93     PathRemoveLastItem(Path);
  94     TempSize = StrSize(TempString);
  95     CopyMem(Path+StrLen(Path), TempString, TempSize);
  96   }
  97   if ((TempString = StrStr(Path, L"\\..")) != NULL && *(TempString + 3) == CHAR_NULL) {
  98     *TempString = CHAR_NULL;
  99     if (!PathRemoveLastItem(Path)) {
 100       *TempString = L'\\';
 101     }
 102   }
 103   //
 104   // Fix up the .
 105   //
 106   while ((TempString = StrStr(Path, L"\\.\\")) != NULL) {
 107     *TempString = CHAR_NULL;
 108     TempString  += 2;
 109     TempSize = StrSize(TempString);
 110     CopyMem(Path+StrLen(Path), TempString, TempSize);
 111   }
 112   if ((TempString = StrStr(Path, L"\\.")) != NULL && *(TempString + 2) == CHAR_NULL) {
 113     *(TempString + 1) = CHAR_NULL;
 114   }
 115
 116   while ((TempString = StrStr(Path, L"\\\\")) != NULL) {
 117     *TempString = CHAR_NULL;
 118     TempString  += 1;
 119     TempSize = StrSize(TempString);
 120     CopyMem(Path+StrLen(Path), TempString, TempSize);
 121   }
 122   if ((TempString = StrStr(Path, L"\\\\")) != NULL && *(TempString + 1) == CHAR_NULL) {
 123     *(TempString) = CHAR_NULL;
 124   }
 125
 126   return (Path);
 127 }
 128