tag_parse_v1.cpp

更新mp3

// $Id: tag_parse_v1.cpp,v 1.27 2002/07/31 13:45:18 t1mpy Exp $

// id3lib: a C++ library for creating and manipulating id3v1/v2 tags
// Copyright 1999, 2000  Scott Thomas Haug
// Copyright 2002 Thijmen Klok ([e-mail])

// This library is free software; you can redistribute it and/or modify it
// under the terms of the GNU Library General Public License as published by
// the Free Software Foundation; either version 2 of the License, or (at your
// option) any later version.
//
// This library is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
// License for more details.
//
// You should have received a copy of the GNU Library General Public License
// along with this library; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

// The id3lib authors encourage improvements and optimisations to be sent to
// the id3lib coordinator.  Please see the README file for details on where to
// send such submissions.  See the AUTHORS file for a list of people who have
// contributed to id3lib.  See the ChangeLog file for a list of changes to
// id3lib.  These files are distributed with id3lib at
// http://download.sourceforge.net/id3lib/

#include "tag_impl.h" //has <stdio.h> "tag.h" "header_tag.h" "frame.h" "field.h" "spec.h" "id3lib_strings.h" "utils.h"
#include "helpers.h"
#include "id3/io_decorators.h" //has "readers.h" "io_helpers.h" "utils.h"
#include "io_strings.h"

using namespace dami;

bool id3::v1::parse(ID3_TagImpl& tag, ID3_Reader& reader)
{
  io::ExitTrigger et(reader);
  
  ID3_Reader::pos_type end = reader.getCur();
  // posn ourselves at 128 bytes from the current position
  if (end < reader.getBeg() + ID3_V1_LEN)
  {
    ID3D_NOTICE( "id3::v1::parse: not enough bytes to parse, pos = " << end );
    return false;
  }
  reader.setCur(end - ID3_V1_LEN);
  ID3_Reader::pos_type beg = reader.getCur();
  //file.seekg(-static_cast<long>(ID3_V1_LEN), ios::cur);
  if (end != beg + ID3_V1_LEN)
  {
    ID3D_WARNING( "id3::v1::parse: failed to reposition " << ID3_V1_LEN << 
                  " bytes" );
    return false;
  }
  
  // read the next 128 bytes in;
  String field = io::readText(reader, ID3_V1_LEN_ID);
  
  // check to see if it was a tag
  if (field != "TAG")
  {
    return false;
  }
  et.setExitPos(beg);
  
  // guess so, let's start checking the v2 tag for frames which are the
  // equivalent of the v1 fields.  When we come across a v1 field that has
  // no current equivalent v2 frame, we create the frame, copy the data
  // from the v1 frame and attach it to the tag

  // (Scott Wheeler) The above comment was nice in theory, but it wasn't
  // first checking (before my hacks) to see if there already was v2 data.

  ID3D_NOTICE("id3::v1::parse: read bytes: " << reader.getCur() - beg);
  String title = io::readTrailingSpaces(reader, ID3_V1_LEN_TITLE);
  field = id3::v2::getTitle(tag);
  if (title.size() > 0 && (field.size() == 0 || field == ""))
  {
    id3::v2::setTitle(tag, title);
  }
  ID3D_NOTICE( "id3::v1::parse: title = \"" << title << "\"" );
  
  ID3D_NOTICE("id3::v1::parse: read bytes: " << reader.getCur() - beg);
  String artist = io::readTrailingSpaces(reader, ID3_V1_LEN_ARTIST);
  field = id3::v2::getArtist(tag);
  if (artist.size() > 0 && (field.size() == 0 || field == ""))
  {
    id3::v2::setArtist(tag, artist);
  }
  ID3D_NOTICE( "id3::v1::parse: artist = \"" << artist << "\"" );
  
  ID3D_NOTICE("id3::v1::parse: read bytes: " << reader.getCur() - beg);
  String album = io::readTrailingSpaces(reader, ID3_V1_LEN_ALBUM);
  field = id3::v2::getAlbum(tag);
  if (album.size() > 0 && (field.size() == 0 || field == ""))
  {
    id3::v2::setAlbum(tag, album);
  }
  ID3D_NOTICE( "id3::v1::parse: album = \"" << title << "\"" );
  
  ID3D_NOTICE("id3::v1::parse: read bytes: " << reader.getCur() - beg);
  String year = io::readTrailingSpaces(reader, ID3_V1_LEN_YEAR);
  field = id3::v2::getYear(tag);
  if (year.size() > 0 && (field.size() == 0 || field == ""))
  {
    id3::v2::setYear(tag, year);
  }
  ID3D_NOTICE( "id3::v1::parse: year = \"" << year << "\"" );
  
  ID3D_NOTICE("id3::v1::parse: read bytes: " << reader.getCur() - beg);
  String comment = io::readTrailingSpaces(reader, ID3_V1_LEN_COMMENT-2);
  // fixes bug for when tracknumber is 0x20
  BString trackno = io::readBinary(reader, ID3_V1_LEN_COMMENT-28);
  if (trackno[0] == '\0')
  {
    if (trackno[1] != '\0')
    { //we've got a tracknumber
      size_t track = trackno[1];
      field = id3::v2::getTrack(tag);
      if (field.size() == 0 || field == "00")
      {
        id3::v2::setTrack(tag, track, 0);
      }
      ID3D_NOTICE( "id3::v1::parse: track = \"" << track << "\"" );
      ID3D_NOTICE( "id3::v1::parse: comment length = \"" << comment.length() << "\"" );
    }
  }
  else
  {
    // trackno[0] != '\0'
    const int paddingsize = (ID3_V1_LEN_COMMENT-2) - comment.size();
    const char * padding = "                            "; //28 spaces

    if (trackno[1] == '\0' || trackno[1] == 0x20 && trackno[0] != 0x20)
    {
      // if there used to be spaces they are gone now, we need to rebuild them
      comment.append(padding, paddingsize);
      comment.append((const char *)trackno.data(), 1);
    }
    else if (trackno[1] != '\0' && trackno[1] != 0x20 &&  trackno[0] != 0x20)
    {
      // if there used to be spaces they are gone now, we need to rebuild them
      comment.append(padding, paddingsize);
      comment.append((const char *)trackno.data(), 2);
    }
  }
  ID3D_NOTICE( "id3::v1::parse: comment = \"" << comment << "\"" );
  if (comment.size() > 0)
  {
    id3::v2::setComment(tag, comment, STR_V1_COMMENT_DESC, "XXX");
  }
  
  ID3D_NOTICE("id3::v1::parse: read bytes: " << reader.getCur() - beg);
  // the GENRE field/frame
  uchar genre = reader.readChar();
  field = id3::v2::getGenre(tag);
  if (genre != 0xFF && (field.size() == 0 || field == ""))
  {
    id3::v2::setGenre(tag, genre);
  }
  ID3D_NOTICE( "id3::v1::parse: genre = \"" << (int) genre << "\"" );

  ID3D_NOTICE("id3::v1::parse: read bytes: " << reader.getCur() - beg);
  return true;
}