field_string_ascii.cpp

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// $Id: field_string_ascii.cpp,v 1.29 2003/03/02 14:23:58 t1mpy Exp $
 
// id3lib: a C++ library for creating and manipulating id3v1/v2 tags
// Copyright 1999, 2000  Scott Thomas Haug
 
// 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 "field_impl.h"
#include "id3/utils.h" // has <config.h> "id3/id3lib_streams.h" "id3/globals.h" "id3/id3lib_strings.h"
#include "io_helpers.h"
 
using namespace dami;


size_t ID3_FieldImpl::Set(const char* data)
{
  size_t len = 0;
  if ((this->GetType() == ID3FTY_TEXTSTRING) && data)
  {
    String str(data);
    len = this->SetText_i(str);
  }
  return len;
}
 
// the ::Get() function for ASCII

size_t ID3_FieldImpl::Get(char* buffer, size_t maxLength) const
{
  size_t size = 0;
  if (this->GetType() == ID3FTY_TEXTSTRING &&
      ID3TE_IS_SINGLE_BYTE_ENC(this->GetEncoding()) &&
      buffer != NULL && maxLength > 0)
  {
    String data = this->GetText();
    size = dami::min(maxLength, data.size());
    ::memcpy(buffer, data.data(), size);
    if (size < maxLength)
    {
      buffer[size] = '\0';
    }
  }
 
  return size;
}
 
size_t ID3_FieldImpl::Get(char* buf, size_t maxLen, size_t index) const
{
  size_t size = 0;
  if (this->GetType() == ID3FTY_TEXTSTRING &&
      ID3TE_IS_SINGLE_BYTE_ENC(this->GetEncoding()) &&
      buf != NULL && maxLen > 0)
  {
    String data = this->GetTextItem(index);
    size = dami::min(maxLen, data.size());
    ::memcpy(buf, data.data(), size);
    if (size < maxLen)
    {
      buf[size] = '\0';
    }
  }
  return size;
}
 
String ID3_FieldImpl::GetText() const
{
  String data;
  if (this->GetType() == ID3FTY_TEXTSTRING)
  {
    data = _text;
  }
  return data;
}
 
String ID3_FieldImpl::GetTextItem(size_t index) const
{
  String data;
  if (this->GetType() == ID3FTY_TEXTSTRING &&
      ID3TE_IS_SINGLE_BYTE_ENC(this->GetEncoding()))
  {
    const char* raw = this->GetRawTextItem(index);
    if (raw != NULL)
    {
      data = raw;
    }
  }
  return data;
}
 
namespace
{
  String getFixed(String data, size_t size)
  {
    String text(data, 0, size);
    if (text.size() < size)
    {
      text.append(size - text.size(), '\0');
    }
    return text;
  }
}
 
 
size_t ID3_FieldImpl::SetText_i(String data)
{
  this->Clear();
  if (_fixed_size > 0)
  {
    _text = getFixed(data, _fixed_size);
  }
  else
  {
    _text = data;
  }
  ID3D_NOTICE( "SetText_i: text = \"" << _text << "\"" );
  _changed = true;
 
  if (_text.size() == 0)
  {
    _num_items = 0;
  }
  else
  {
    _num_items = 1;
  }
 
  return _text.size();
}
 
size_t ID3_FieldImpl::SetText(String data)
{
  size_t len = 0;
  if (this->GetType() == ID3FTY_TEXTSTRING)
  {
    len = this->SetText_i(data);
  }
  return len;
}
 

size_t ID3_FieldImpl::AddText_i(String data)
{
  size_t len = 0;  // how much of str we copied into this field (max is strLen)
  ID3D_NOTICE ("ID3_FieldImpl::AddText_i: Adding \"" << data << "\"" );
  if (this->GetNumTextItems() == 0)
  {
    // there aren't any text items in the field so just assign the string to
    // the field
    len = this->SetText_i(data);
  }
  else
  {
 
    // ASSERT(_fixed_size == 0)
    _text += '\0';
    if (ID3TE_IS_DOUBLE_BYTE_ENC(this->GetEncoding()))
    {
      _text += '\0';
    }
    _text.append(data);
    len = data.size();
    _num_items++;
  }
 
  return len;
}
 
size_t ID3_FieldImpl::AddText(String data)
{
  size_t len = 0;
  if (this->GetType() == ID3FTY_TEXTSTRING)
  {
    len = this->AddText_i(data);
  }
  return len;
}
 
size_t ID3_FieldImpl::Add(const char* data)
{
  size_t len = 0;
  if (this->GetType() == ID3FTY_TEXTSTRING)
  {
    String str(data);
    len = this->AddText_i(str);
  }
  return len;
}
 
const char* ID3_FieldImpl::GetRawText() const
{
  const char* text = NULL;
  if (this->GetType() == ID3FTY_TEXTSTRING &&
      ID3TE_IS_SINGLE_BYTE_ENC(this->GetEncoding()))
  {
    text = _text.c_str();
  }
  return text;
}
 
const char* ID3_FieldImpl::GetRawTextItem(size_t index) const
{
  const char* text = NULL;
  if (this->GetType() == ID3FTY_TEXTSTRING &&
      ID3TE_IS_SINGLE_BYTE_ENC(this->GetEncoding()) &&
      index < this->GetNumTextItems())
  {
    text = _text.c_str();
    for (size_t i = 0; i < index; ++i)
    {
      text += strlen(text) + 1;
    }
  }
  return text;
}
 
namespace
{
  // UTF-16BE is stored big-endian without a BOM; id3lib keeps unicode text in
  // host byte order internally, so swap the byte pairs after reading.
  void swapPairs(String& s)
  {
    for (size_t i = 0; i + 1 < s.size(); i += 2)
    {
      char t = s[i]; s[i] = s[i+1]; s[i+1] = t;
    }
  }
 
  String readEncodedText(ID3_Reader& reader, size_t len, ID3_TextEnc enc)
  {
    if (ID3TE_IS_SINGLE_BYTE_ENC(enc))
    {
      return io::readText(reader, len);
    }
    String text = io::readUnicodeText(reader, len);
    if (enc == ID3TE_UTF16BE)
    {
      swapPairs(text);
    }
    return text;
  }
 
  String readEncodedString(ID3_Reader& reader, ID3_TextEnc enc)
  {
    if (ID3TE_IS_SINGLE_BYTE_ENC(enc))
    {
      return io::readString(reader);
    }
    String text = io::readUnicodeString(reader);
    if (enc == ID3TE_UTF16BE)
    {
      swapPairs(text);
    }
    return text;
  }
 
  size_t writeEncodedText(ID3_Writer& writer, String data, ID3_TextEnc enc)
  {
    if (ID3TE_IS_SINGLE_BYTE_ENC(enc))
    {
      return io::writeText(writer, data);
    }
    // UTF-16 carries a BOM, UTF-16BE does not.
    return io::writeUnicodeText(writer, data, enc != ID3TE_UTF16BE);
  }
 
  size_t writeEncodedString(ID3_Writer& writer, String data, ID3_TextEnc enc)
  {
    if (ID3TE_IS_SINGLE_BYTE_ENC(enc))
    {
      return io::writeString(writer, data);
    }
    // UTF-16 carries a BOM, UTF-16BE does not.
    return io::writeUnicodeString(writer, data, enc != ID3TE_UTF16BE);
  }
}
 
bool ID3_FieldImpl::ParseText(ID3_Reader& reader)
{
  ID3D_NOTICE( "ID3_Field::ParseText(): reader.getBeg() = " << reader.getBeg() );
  ID3D_NOTICE( "ID3_Field::ParseText(): reader.getCur() = " << reader.getCur() );
  ID3D_NOTICE( "ID3_Field::ParseText(): reader.getEnd() = " << reader.getEnd() );
  this->Clear();
 
  ID3_TextEnc enc = this->GetEncoding();
  size_t fixed_size = this->Size();
  if (fixed_size)
  {
    ID3D_NOTICE( "ID3_Field::ParseText(): fixed size string" );
    // The string is of fixed length
    String text = readEncodedText(reader, fixed_size, enc);
    this->SetText(text);
    ID3D_NOTICE( "ID3_Field::ParseText(): fixed size string = " << text );
  }
  else if (_flags & ID3FF_LIST)
  {
    ID3D_NOTICE( "ID3_Field::ParseText(): text list" );
    // lists are always the last field in a frame.  parse all remaining
    // characters in the reader
    while (!reader.atEnd())
    {
      String text = readEncodedString(reader, enc);
      this->AddText(text);
      ID3D_NOTICE( "ID3_Field::ParseText(): adding string = " << text );
    }
  }
  else if (_flags & ID3FF_CSTR)
  {
    ID3D_NOTICE( "ID3_Field::ParseText(): null terminated string" );
    String text = readEncodedString(reader, enc);
    this->SetText(text);
    ID3D_NOTICE( "ID3_Field::ParseText(): null terminated string = " << text );
  }
  else
  {
    ID3D_NOTICE( "ID3_Field::ParseText(): last field string" );
    String text = readEncodedText(reader, reader.remainingBytes(), enc);
    // not null terminated.
    this->AddText(text);
    ID3D_NOTICE( "ID3_Field::ParseText(): last field string = " << text );
  }
 
  _changed = false;
  return true;
}
 
void ID3_FieldImpl::RenderText(ID3_Writer& writer) const
{
  ID3_TextEnc enc = this->GetEncoding();
 
  if (_flags & ID3FF_CSTR)
  {
    writeEncodedString(writer, _text, enc);
  }
  else
  {
    writeEncodedText(writer, _text, enc);
  }
  _changed = false;
};

size_t ID3_FieldImpl::GetNumTextItems() const
{
  return _num_items;
}