ShellPkg/Library/BasePathLib/BasePathLib.c

   1 /** @file
   2   Provides interface to path manipulation functions.
   3
   4   Copyright (c) 2011 - 2014, 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 #include <Protocol/SimpleTextIn.h>
  19
  20 /**
  21   Removes the last directory or file entry in a path by changing the last
  22   L'\' to a CHAR_NULL.
  23
  24   @param[in, out] Path    The pointer to the path to modify.
  25
  26   @retval FALSE     Nothing was found to remove.
  27   @retval TRUE      A directory or file was removed.
  28 **/
  29 BOOLEAN
  30 EFIAPI
  31 PathRemoveLastItem(
  32   IN OUT CHAR16 *Path
  33   )
  34 {
  35   CHAR16        *Walker;
  36   CHAR16        *LastSlash;
  37   //
  38   // get directory name from path... ('chop' off extra)
  39   //
  40   for ( Walker = Path, LastSlash = NULL
  41       ; Walker != NULL && *Walker != CHAR_NULL
  42       ; Walker++
  43      ){
  44     if (*Walker == L'\\' && *(Walker + 1) != CHAR_NULL) {
  45       LastSlash = Walker+1;
  46     }
  47   }
  48   if (LastSlash != NULL) {
  49     *LastSlash = CHAR_NULL;
  50     return (TRUE);
  51   }
  52   return (FALSE);
  53 }
  54
  55 /**
  56   Function to clean up paths.
  57
  58   - Single periods in the path are removed.
  59   - Double periods in the path are removed along with a single parent directory.
  60   - Forward slashes L'/' are converted to backward slashes L'\'.
  61
  62   This will be done inline and the existing buffer may be larger than required
  63   upon completion.
  64
  65   @param[in] Path       The pointer to the string containing the path.
  66
  67   @retval NULL          An error occured.
  68   @return Path in all other instances.
  69 **/
  70 CHAR16*
  71 EFIAPI
  72 PathCleanUpDirectories(
  73   IN CHAR16 *Path
  74   )
  75 {
  76   CHAR16  *TempString;
  77   UINTN   TempSize;
  78   if (Path==NULL) {
  79     return(NULL);
  80   }
  81
  82   //
  83   // Fix up the '/' vs '\'
  84   //
  85   for (TempString = Path ; TempString != NULL && *TempString != CHAR_NULL ; TempString++) {
  86     if (*TempString == L'/') {
  87       *TempString = L'\\';
  88     }
  89   }
  90
  91   //
  92   // Fix up the ..
  93   //
  94   while ((TempString = StrStr(Path, L"\\..\\")) != NULL) {
  95     *TempString = CHAR_NULL;
  96     TempString  += 4;
  97     PathRemoveLastItem(Path);
  98     TempSize = StrSize(TempString);
  99     CopyMem(Path+StrLen(Path), TempString, TempSize);
 100   }
 101   if ((TempString = StrStr(Path, L"\\..")) != NULL && *(TempString + 3) == CHAR_NULL) {
 102     *TempString = CHAR_NULL;
 103     PathRemoveLastItem(Path);
 104   }
 105
 106   //
 107   // Fix up the .
 108   //
 109   while ((TempString = StrStr(Path, L"\\.\\")) != NULL) {
 110     *TempString = CHAR_NULL;
 111     TempString  += 2;
 112     TempSize = StrSize(TempString);
 113     CopyMem(Path+StrLen(Path), TempString, TempSize);
 114   }
 115   if ((TempString = StrStr(Path, L"\\.")) != NULL && *(TempString + 2) == CHAR_NULL) {
 116     *(TempString + 1) = CHAR_NULL;
 117   }
 118
 119   while ((TempString = StrStr(Path, L"\\\\")) != NULL) {
 120     *TempString = CHAR_NULL;
 121     TempString  += 1;
 122     TempSize = StrSize(TempString);
 123     CopyMem(Path+StrLen(Path), TempString, TempSize);
 124   }
 125   if ((TempString = StrStr(Path, L"\\\\")) != NULL && *(TempString + 1) == CHAR_NULL) {
 126     *(TempString) = CHAR_NULL;
 127   }
 128
 129   return (Path);
 130 }
 131