gecko-dev/xpcom/io/nsLinebreakConverter.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef nsLinebreakConverter_h_
#define nsLinebreakConverter_h_

#include "nscore.h"
#include "nsString.h"

// utility class for converting between different line breaks.

class nsLinebreakConverter {
 public:
  // Note: enum must match char* array in GetLinebreakString
  typedef enum {
    eLinebreakAny,  // any kind of linebreak (i.e. "don't care" source)

    eLinebreakPlatform,  // platform linebreak
    eLinebreakContent,   // Content model linebreak (LF)
    eLinebreakNet,       // Form submission linebreak (CRLF)

    eLinebreakMac,      // CR
    eLinebreakUnix,     // LF
    eLinebreakWindows,  // CRLF

    eLinebreakSpace  // space characters. Only valid as destination type

  } ELinebreakType;

  enum { kIgnoreLen = -1 };

  /* ConvertLineBreaks
   * Convert line breaks in the supplied string, allocating and returning
   * a new buffer. Returns nullptr on failure.
   * @param aSrc: the source string. if aSrcLen == kIgnoreLen this string is
   *              assumed to be null terminated, otherwise it must be at least
   *              aSrcLen long.
   * @param aSrcBreaks: the line breaks in the source. If unknown, pass
   *              eLinebreakAny.  If known, pass the known value, as this may
   *              be more efficient.
   * @param aDestBreaks: the line breaks you want in the output.
   * @param aSrcLen: length of the source. If -1, the source is assumed to be a
   *              null-terminated string.
   * @param aOutLen: used to return character length of returned buffer, if not
   *              null.
   */
  static char* ConvertLineBreaks(const char* aSrc, ELinebreakType aSrcBreaks,
                                 ELinebreakType aDestBreaks,
                                 int32_t aSrcLen = kIgnoreLen,
                                 int32_t* aOutLen = nullptr);

  /* ConvertUnicharLineBreaks
   * Convert line breaks in the supplied string, allocating and returning
   * a new buffer. Returns nullptr on failure.
   * @param aSrc: the source string. if aSrcLen == kIgnoreLen this string is
   *              assumed to be null terminated, otherwise it must be at least
   *              aSrcLen long.
   * @param aSrcBreaks: the line breaks in the source. If unknown, pass
   *              eLinebreakAny.  If known, pass the known value, as this may
   *              be more efficient.
   * @param aDestBreaks: the line breaks you want in the output.
   * @param aSrcLen: length of the source, in characters. If -1, the source is
   *              assumed to be a null-terminated string.
   * @param aOutLen: used to return character length of returned buffer, if not
   *              null.
   */
  static char16_t* ConvertUnicharLineBreaks(const char16_t* aSrc,
                                            ELinebreakType aSrcBreaks,
                                            ELinebreakType aDestBreaks,
                                            int32_t aSrcLen = kIgnoreLen,
                                            int32_t* aOutLen = nullptr);

  /* ConvertStringLineBreaks
   * Convert line breaks in the supplied string, changing the string buffer
   * (i.e. in-place conversion)
   * @param ioString: the string to be converted.
   * @param aSrcBreaks: the line breaks in the source. If unknown, pass
   *              eLinebreakAny.  If known, pass the known value, as this may
   *              be more efficient.
   * @param aDestBreaks: the line breaks you want in the output.
   * @param aSrcLen: length of the source, in characters. If -1, the source is
   *              assumed to be a null-terminated string.
   */
  static nsresult ConvertStringLineBreaks(nsString& aIoString,
                                          ELinebreakType aSrcBreaks,
                                          ELinebreakType aDestBreaks);

  /* ConvertLineBreaksInSitu
   * Convert line breaks in place if possible. NOTE: THIS MAY REALLOCATE THE
   * BUFFER, BUT IT WON'T FREE THE OLD BUFFER (because it doesn't know how). So
   * be prepared to keep a copy of the old pointer, and free it if this passes
   * back a new pointer.  ALSO NOTE: DON'T PASS A STATIC STRING POINTER TO THIS
   * FUNCTION.
   *
   * @param ioBuffer: the source buffer. if aSrcLen == kIgnoreLen this string
   *              is assumed to be null terminated, otherwise it must be at
   *              least aSrcLen long.
   * @param aSrcBreaks: the line breaks in the source. If unknown, pass
   *              eLinebreakAny.  If known, pass the known value, as this may
   *              be more efficient.
   * @param aDestBreaks: the line breaks you want in the output.
   * @param aSrcLen: length of the source. If -1, the source is assumed to be a
   *              null-terminated string.
   * @param aOutLen: used to return character length of returned buffer, if not
   *              null.
   */
  static nsresult ConvertLineBreaksInSitu(char** aIoBuffer,
                                          ELinebreakType aSrcBreaks,
                                          ELinebreakType aDestBreaks,
                                          int32_t aSrcLen = kIgnoreLen,
                                          int32_t* aOutLen = nullptr);

  /* ConvertUnicharLineBreaksInSitu
   * Convert line breaks in place if possible. NOTE: THIS MAY REALLOCATE THE
   * BUFFER, BUT IT WON'T FREE THE OLD BUFFER (because it doesn't know how). So
   * be prepared to keep a copy of the old pointer, and free it if this passes
   * back a new pointer.
   *
   * @param ioBuffer: the source buffer. if aSrcLen == kIgnoreLen this string
   *              is assumed to be null terminated, otherwise it must be at
   *              least aSrcLen long.
   * @param aSrcBreaks: the line breaks in the source. If unknown, pass
   *              eLinebreakAny.  If known, pass the known value, as this may
   *              be more efficient.
   * @param aDestBreaks: the line breaks you want in the output.
   * @param aSrcLen: length of the source in characters. If -1, the source is
   *              assumed to be a null-terminated string.
   * @param aOutLen: used to return character length of returned buffer, if not
   *              null.
   */
  static nsresult ConvertUnicharLineBreaksInSitu(char16_t** aIoBuffer,
                                                 ELinebreakType aSrcBreaks,
                                                 ELinebreakType aDestBreaks,
                                                 int32_t aSrcLen = kIgnoreLen,
                                                 int32_t* aOutLen = nullptr);
};

#endif  // nsLinebreakConverter_h_