MdePkg BaseLib: API PathRemoveLastItem not handle root paths properly

[mirror_edk2.git] / MdePkg / Library / BaseLib / FilePaths.c

/** @file\r
  Defines file-path manipulation functions.\r
\r
  Copyright (c) 2011 - 2016, Intel Corporation. All rights reserved.<BR>\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php.\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
**/\r
#include  <Library/BaseMemoryLib.h>\r
#include  <Library/BaseLib.h>\r
\r
/**\r
  Removes the last directory or file entry in a path. For a path which is\r
  like L"fs0:startup.nsh", it's converted to L"fs0:".\r
\r
  @param[in,out] Path     A pointer to the path to modify.\r
\r
  @retval FALSE     Nothing was found to remove.\r
  @retval TRUE      A directory or file was removed.\r
**/\r
BOOLEAN\r
EFIAPI\r
PathRemoveLastItem(\r
  IN OUT CHAR16 *Path\r
  )\r
{\r
  CHAR16        *Walker;\r
  CHAR16        *LastSlash;\r
  //\r
  // get directory name from path... ('chop' off extra)\r
  //\r
  for ( Walker = Path, LastSlash = NULL\r
      ; Walker != NULL && *Walker != CHAR_NULL\r
      ; Walker++\r
     ){\r
    if (*Walker == L'\\' && *(Walker + 1) != CHAR_NULL) {\r
      LastSlash = Walker+1;\r
    } else if (*Walker == L':' && *(Walker + 1) != L'\\' && *(Walker + 1) != CHAR_NULL) {\r
      LastSlash = Walker+1;\r
    }\r
  }\r
  if (LastSlash != NULL) {\r
    *LastSlash = CHAR_NULL;\r
    return (TRUE);\r
  }\r
  return (FALSE);\r
}\r
\r
/**\r
  Function to clean up paths.\r
\r
  - Single periods in the path are removed.\r
  - Double periods in the path are removed along with a single parent directory.\r
  - Forward slashes L'/' are converted to backward slashes L'\'.\r
\r
  This will be done inline and the existing buffer may be larger than required\r
  upon completion.\r
\r
  @param[in] Path       The pointer to the string containing the path.\r
\r
  @return       Returns Path, otherwise returns NULL to indicate that an error has occured.\r
**/\r
CHAR16*\r
EFIAPI\r
PathCleanUpDirectories(\r
  IN CHAR16 *Path\r
  )\r
{\r
  CHAR16  *TempString;\r
  UINTN   TempSize;\r
\r
  if (Path==NULL) {\r
    return(NULL);\r
  }\r
  //\r
  // Fix up the '/' vs '\'\r
  //\r
  for (TempString = Path ; TempString != NULL && *TempString != CHAR_NULL ; TempString++) {\r
    if (*TempString == L'/') {\r
      *TempString = L'\\';\r
    }\r
  }\r
  //\r
  // Fix up the ..\r
  //\r
  while ((TempString = StrStr(Path, L"\\..\\")) != NULL) {\r
    *TempString = CHAR_NULL;\r
    TempString  += 4;\r
    PathRemoveLastItem(Path);\r
    TempSize = StrSize(TempString);\r
    CopyMem(Path+StrLen(Path), TempString, TempSize);\r
  }\r
  if ((TempString = StrStr(Path, L"\\..")) != NULL && *(TempString + 3) == CHAR_NULL) {\r
    *TempString = CHAR_NULL;\r
    if (!PathRemoveLastItem(Path)) {\r
      *TempString = L'\\';\r
    }\r
  }\r
  //\r
  // Fix up the .\r
  //\r
  while ((TempString = StrStr(Path, L"\\.\\")) != NULL) {\r
    *TempString = CHAR_NULL;\r
    TempString  += 2;\r
    TempSize = StrSize(TempString);\r
    CopyMem(Path+StrLen(Path), TempString, TempSize);\r
  }\r
  if ((TempString = StrStr(Path, L"\\.")) != NULL && *(TempString + 2) == CHAR_NULL) {\r
    *(TempString + 1) = CHAR_NULL;\r
  }\r
\r
  while ((TempString = StrStr(Path, L"\\\\")) != NULL) {\r
    *TempString = CHAR_NULL;\r
    TempString  += 1;\r
    TempSize = StrSize(TempString);\r
    CopyMem(Path+StrLen(Path), TempString, TempSize);\r
  }\r
  if ((TempString = StrStr(Path, L"\\\\")) != NULL && *(TempString + 1) == CHAR_NULL) {\r
    *(TempString) = CHAR_NULL;\r
  }\r
\r
  return (Path);\r
}\r
\r