MdeModulePkg/Udf: Refine function description comments

[mirror_edk2.git] / MdeModulePkg / Universal / Disk / UdfDxe / FileName.c

/** @file\r
  Helper functions for mangling file names in UDF/ECMA-167 file systems.\r
\r
  Copyright (C) 2014-2017 Paulo Alcantara <pcacjr@zytor.com>\r
\r
  This program and the accompanying materials are licensed and made available\r
  under the terms and conditions of the BSD License which accompanies this\r
  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, WITHOUT\r
  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
**/\r
\r
#include "Udf.h"\r
\r
/**\r
  Trim the leading and trailing spaces for a give Unicode string.\r
\r
  @param[in]  String              The Unicode string to trim.\r
\r
  @return  A pointer to the trimmed string.\r
\r
**/\r
CHAR16 *\r
TrimString (\r
  IN CHAR16    *String\r
  )\r
{\r
  CHAR16       *TempString;\r
\r
  for ( ; *String != L'\0' && *String == L' '; String++) {\r
    ;\r
  }\r
\r
  TempString = String + StrLen (String) - 1;\r
  while ((TempString >= String) && (*TempString == L' ')) {\r
    TempString--;\r
  }\r
\r
  *(TempString + 1) = L'\0';\r
\r
  return String;\r
}\r
\r
/**\r
  Replace the content of a Unicode string with the content of another Unicode\r
  string.\r
\r
  @param[in]  Destination         A pointer to a Unicode string.\r
  @param[in]  Source              A pointer to a Unicode string.\r
\r
**/\r
VOID\r
ReplaceLeft (\r
  IN CHAR16         *Destination,\r
  IN CONST CHAR16   *Source\r
  )\r
{\r
  CONST CHAR16      *EndString;\r
\r
  EndString = Source + StrLen (Source);\r
  while (Source <= EndString) {\r
    *Destination++ = *Source++;\r
  }\r
}\r
\r
/**\r
  Remove one or more consecutive backslashes starting from the second character\r
  of a given Unicode string.\r
\r
  @param[in]  String              A pointer to a Unicode string.\r
\r
  @return  A pointer to the modified string.\r
\r
**/\r
CHAR16 *\r
ExcludeTrailingBackslashes (\r
  IN CHAR16                    *String\r
  )\r
{\r
  CHAR16                       *TempString;\r
\r
  switch (*(String + 1)) {\r
  case L'\\':\r
    break;\r
  case L'\0':\r
  default:\r
    String++;\r
    goto Exit;\r
  }\r
\r
  TempString = String;\r
  while (*TempString != L'\0' && *TempString == L'\\') {\r
    TempString++;\r
  }\r
\r
  if (TempString - 1 > String) {\r
    ReplaceLeft (String + 1, TempString);\r
  }\r
\r
  String++;\r
\r
Exit:\r
  return String;\r
}\r
\r
/**\r
  Mangle a filename by cutting off trailing whitespaces, "\\", "." and "..".\r
\r
  @param[in] FileName Filename.\r
\r
  @retval The mangled Filename.\r
\r
**/\r
CHAR16 *\r
MangleFileName (\r
  IN CHAR16        *FileName\r
  )\r
{\r
  CHAR16           *FileNameSavedPointer;\r
  CHAR16           *TempFileName;\r
  UINTN            BackslashesNo;\r
\r
  if (FileName == NULL || *FileName == L'\0') {\r
    FileName = NULL;\r
    goto Exit;\r
  }\r
\r
  FileName = TrimString (FileName);\r
  if (*FileName == L'\0') {\r
    goto Exit;\r
  }\r
\r
  if ((StrLen (FileName) > 1) && (FileName[StrLen (FileName) - 1] == L'\\')) {\r
    FileName[StrLen (FileName) - 1] = L'\0';\r
  }\r
\r
  FileNameSavedPointer = FileName;\r
\r
  if (FileName[0] == L'.') {\r
    if (FileName[1] == L'.') {\r
      if (FileName[2] == L'\0') {\r
        goto Exit;\r
      } else {\r
        FileName += 2;\r
      }\r
    } else if (FileName[1] == L'\0') {\r
      goto Exit;\r
    }\r
  }\r
\r
  while (*FileName != L'\0') {\r
    if (*FileName == L'\\') {\r
      FileName = ExcludeTrailingBackslashes (FileName);\r
    } else if (*FileName == L'.') {\r
      switch (*(FileName + 1)) {\r
      case L'\0':\r
        *FileName = L'\0';\r
        break;\r
      case L'\\':\r
        TempFileName = FileName + 1;\r
        TempFileName = ExcludeTrailingBackslashes (TempFileName);\r
        ReplaceLeft (FileName, TempFileName);\r
        break;\r
      case '.':\r
        if ((*(FileName - 1) != L'\\') && ((*(FileName + 2) != L'\\') ||\r
                                           (*(FileName + 2) != L'\0'))) {\r
          FileName++;\r
          continue;\r
        }\r
\r
        BackslashesNo = 0;\r
        TempFileName = FileName - 1;\r
        while (TempFileName >= FileNameSavedPointer) {\r
          if (*TempFileName == L'\\') {\r
            if (++BackslashesNo == 2) {\r
              break;\r
            }\r
          }\r
\r
          TempFileName--;\r
        }\r
\r
        TempFileName++;\r
\r
        if ((*TempFileName == L'.') && (*(TempFileName + 1) == L'.')) {\r
          FileName += 2;\r
        } else {\r
          if (*(FileName + 2) != L'\0') {\r
            ReplaceLeft (TempFileName, FileName + 3);\r
            if (*(TempFileName - 1) == L'\\') {\r
              FileName = TempFileName;\r
              ExcludeTrailingBackslashes (TempFileName - 1);\r
              TempFileName = FileName;\r
            }\r
          } else {\r
            *TempFileName = L'\0';\r
          }\r
\r
          FileName = TempFileName;\r
        }\r
\r
        break;\r
      default:\r
        FileName++;\r
      }\r
    } else {\r
      FileName++;\r
    }\r
  }\r
\r
  FileName = FileNameSavedPointer;\r
  if ((StrLen (FileName) > 1) && (FileName [StrLen (FileName) - 1] == L'\\')) {\r
    FileName [StrLen (FileName) - 1] = L'\0';\r
  }\r
\r
Exit:\r
  return FileName;\r
}\r