id3lib  3.8.3
header_tag.cpp
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1 // $Id: header_tag.cpp,v 1.25 2003/03/02 14:30:46 t1mpy Exp $
2 
3 // id3lib: a C++ library for creating and manipulating id3v1/v2 tags
4 // Copyright 1999, 2000 Scott Thomas Haug
5 // Copyright 2002 Thijmen Klok (thijmen@id3lib.org)
6 
7 // This library is free software; you can redistribute it and/or modify it
8 // under the terms of the GNU Library General Public License as published by
9 // the Free Software Foundation; either version 2 of the License, or (at your
10 // option) any later version.
11 //
12 // This library is distributed in the hope that it will be useful, but WITHOUT
13 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 // FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
15 // License for more details.
16 //
17 // You should have received a copy of the GNU Library General Public License
18 // along with this library; if not, write to the Free Software Foundation,
19 // Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 
21 // The id3lib authors encourage improvements and optimisations to be sent to
22 // the id3lib coordinator. Please see the README file for details on where to
23 // send such submissions. See the AUTHORS file for a list of people who have
24 // contributed to id3lib. See the ChangeLog file for a list of changes to
25 // id3lib. These files are distributed with id3lib at
26 // http://download.sourceforge.net/id3lib/
27 
28 
29 #include "header_tag.h"
30 #include "id3/utils.h" // has <config.h> "id3/id3lib_streams.h" "id3/globals.h" "id3/id3lib_strings.h"
31 #include "tag.h"
32 #include "io_helpers.h"
33 #include "spec.h"
34 
35 using namespace dami;
36 
37 const char* const ID3_TagHeader::ID = "ID3";
38 
40 {
41  bool changed = this->ID3_Header::SetSpec(spec);
42  if (changed)
43  {
44  if (_info)
45  {
46  _flags.set(HEADER_FLAG_EXPERIMENTAL, _info->is_experimental);
47  _flags.set(HEADER_FLAG_EXTENDED, _info->is_extended);
48  }
49  }
50  return changed;
51 }
52 
53 size_t ID3_TagHeader::Size() const
54 {
55  size_t bytesUsed = ID3_TagHeader::SIZE;
56 
57  if (_info && _info->is_extended)
58  {
59  bytesUsed += _info->extended_bytes;
60  }
61 
62  return bytesUsed;
63 }
64 
65 
66 void ID3_TagHeader::Render(ID3_Writer& writer) const
67 {
68  writer.writeChars((uchar *) ID, strlen(ID));
69 
72 
73  // set the flags byte in the header
74  writer.writeChar(static_cast<uchar>(_flags.get() & MASK8));
75  io::writeUInt28(writer, this->GetDataSize()); //now includes the extended header
76 
77  // now we render the extended header
78  if (_flags.test(HEADER_FLAG_EXTENDED))
79  {
80  if (this->GetSpec() == ID3V2_4_0)
81  {
82  io::writeUInt28(writer, 6); //write 4 bytes of v2.4.0 ext header containing size '6'
83  io::writeBENumber(writer, 1, 1); //write that it has only one flag byte (value '1')
84  io::writeBENumber(writer, 0, 1); //write flag byte with value '0'
85  }
86  else if (this->GetSpec() == ID3V2_3_0)
87  {
88  io::writeBENumber(writer, 6, sizeof(uint32));
89  for (size_t i = 0; i < 6; ++i)
90  {
91  if (writer.writeChar('\0') == ID3_Writer::END_OF_WRITER)
92  {
93  break;
94  }
95  }
96  }
97  // else //not implemented
98  }
99 }
100 
102 {
103  io::ExitTrigger et(reader);
104  if (!ID3_Tag::IsV2Tag(reader))
105  {
106  ID3D_NOTICE( "ID3_TagHeader::Parse(): not an id3v2 header" );
107  return false;
108  }
109 
110  uchar id[3];
111  reader.readChars(id, 3);
112  // The spec version is determined with the MAJOR and MINOR OFFSETs
113  uchar major = reader.readChar();
114  uchar minor = reader.readChar();
115  this->SetSpec(ID3_VerRevToV2Spec(major, minor));
116 
117  // Get the flags at the appropriate offset
118  _flags.set(static_cast<ID3_Flags::TYPE>(reader.readChar()));
119 
120  // set the data size
121  this->SetDataSize(io::readUInt28(reader));
122 
123  if (_flags.test(HEADER_FLAG_EXTENDED) && this->GetSpec() == ID3V2_2_1)
124  {
125  //couldn't find anything about this in the draft specifying 2.2.1 -> http://www.id3.org/pipermail/id3v2/2000-April/000126.html
126  _flags.set(HEADER_FLAG_EXTENDED, false);
127  _info->extended_bytes = 0;
128  // rest is checked at ParseExtended()
129  }
130  et.setExitPos(reader.getCur());
131  return true;
132 }
133 
135 {
136  if (this->GetSpec() == ID3V2_3_0)
137  {
138 /*
139  Extended header size $xx xx xx xx
140  Extended Flags $xx xx
141  Size of padding $xx xx xx xx
142 */
143  // skip over header size, we are not using it anyway, we calculate it
144  reader.setCur(reader.getCur()+4); //Extended header size
145  //io::readBENumber(reader, 4); //Extended header size
146  uint16 tmpval = io::readBENumber(reader, 2); //Extended Flags
147  // skip over padding size, we are not using it anyway
148  reader.setCur(reader.getCur()+4); //Size of padding
149  // io::readBENumber(reader, 4); //Size of padding
150  if (tmpval != 0) //there is only one flag defined in ID3V2_3_0: crc
151  {
152  //skip over crc data, we are not using it anyway
153  reader.setCur(reader.getCur()+4); //Crc
154  //io::readBENumber(reader, 4); //Crc
155  _info->extended_bytes = 14;
156  }
157  else
158  _info->extended_bytes = 10;
159  }
160  if (this->GetSpec() == ID3V2_4_0)
161  {
162 /*
163  Extended header size 4 * %0xxxxxxx
164  Number of flag bytes $01
165  Extended Flags $xx
166 */
167  uint16 i;
168  uint16 extrabytes;
169 
170  io::readUInt28(reader);
171  const int extflagbytes = reader.readChar(); //Number of flag bytes
172  ID3_Flags* extflags[1]; // ID3V2_4_0 has 1 flag byte, extflagbytes should be equal to 1
173  for (i = 0; i < extflagbytes; ++i)
174  {
175  extflags[i] = new ID3_Flags;
176  extflags[i]->set(reader.readChar()); //flags
177  }
178  extrabytes = 0;
179  //extflags[0]->test(EXT_HEADER_FLAG_BIT1); // ID3V2_4_0 ext header flag bit 1 *should* be 0
180  if (extflags[0]->test(EXT_HEADER_FLAG_BIT2))
181  {
182  // ID3V2_4_0 ext header flag bit 2 = Tag is an update
183  // read size
184  extrabytes += 1; // add a byte for the char containing the extflagdatasize
185  const int extheaderflagdatasize = reader.readChar();
186  extrabytes += extheaderflagdatasize;
187  // Set the cursor right; we are not parsing the data, no-one is using extended flags anyway
188  reader.setCur(reader.getCur() + extheaderflagdatasize);
189  //reader.readChars(buf, extheaderflagdatasize); //buf should be at least 127 bytes = max extended header flagdata size
190  }
191  if (extflags[0]->test(EXT_HEADER_FLAG_BIT3))
192  {
193  // ID3V2_4_0 ext header flag bit 3 = CRC data present
194  // read size
195  extrabytes += 1; // add a byte for the char containing the extflagdatasize
196  const int extheaderflagdatasize = reader.readChar();
197  extrabytes += extheaderflagdatasize;
198  // Set the cursor right; we are not parsing the data, no-one is using extended flags anyway
199  reader.setCur(reader.getCur() + extheaderflagdatasize);
200  //reader.readChars(buf, extheaderflagdatasize); //buf should be at least 127 bytes = max extended header flagdata size
201  }
202  if (extflags[0]->test(EXT_HEADER_FLAG_BIT4))
203  {
204  // ID3V2_4_0 ext header flag bit 4 = Tag restrictions
205  // read size
206  extrabytes += 1; // add a byte for the char containing the extflagdatasize
207  const int extheaderflagdatasize = reader.readChar();
208  extrabytes += extheaderflagdatasize;
209  // Set the cursor right; we are not parsing the data, no-one is using extended flags anyway
210  reader.setCur(reader.getCur() + extheaderflagdatasize);
211  //reader.readChars(buf, extheaderflagdatasize); //buf should be at least 127 bytes = max extended header flagdata size
212  }
213  _info->extended_bytes = 5 + extflagbytes + extrabytes;
214  }
215  // a bit unorthodox, but since we are not using any of the extended header, but were merely
216  // parsing it to get the cursor right, we delete it. Be Gone !
217  _flags.set(HEADER_FLAG_EXTENDED, false);
218  if (_info)
219  {
220  _data_size -= _info->extended_bytes;
221  _info->extended_bytes = 0;
222  }//else there is a tag with a higher or lower version than supported
223 }
224 
flags_t TYPE
Definition: flags.h:36
bool set(TYPE f)
Definition: flags.h:43
virtual bool SetSpec(ID3_V2Spec)
Definition: header.cpp:34
virtual pos_type setCur(pos_type pos)=0
Set the value of the current position for reading.
virtual pos_type getCur()=0
Return the current position in the reader.
virtual size_type readChars(char_type buf[], size_type len)=0
Read up to len characters into buf and advance the internal position accordingly.
virtual int_type readChar()
Read a single character and advance the internal position.
Definition: reader.h:65
void Render(ID3_Writer &) const
Definition: header_tag.cpp:66
bool Parse(ID3_Reader &)
Definition: header_tag.cpp:101
void ParseExtended(ID3_Reader &)
Definition: header_tag.cpp:134
static const char *const ID
Definition: header_tag.h:100
size_t Size() const
Definition: header_tag.cpp:53
bool SetSpec(ID3_V2Spec)
Definition: header_tag.cpp:39
static size_t IsV2Tag(const uchar *)
Analyses a buffer to determine if we have a valid ID3v2 tag header.
Definition: tag.cpp:955
virtual size_type writeChars(const char_type buf[], size_type len)=0
Write up to len characters into buf and advance the internal position accordingly.
virtual int_type writeChar(char_type ch)
Write a single character and advance the internal position.
Definition: writer.h:71
static const int_type END_OF_WRITER
Definition: writer.h:41
#define MASK8
Definition: globals.h:705
ID3_V2Spec
Definition: globals.h:162
@ ID3V2_LATEST
Definition: globals.h:169
@ ID3V2_4_0
Definition: globals.h:167
@ ID3V2_2_1
Definition: globals.h:165
@ ID3V2_3_0
Definition: globals.h:166
unsigned char uchar
Definition: globals.h:114
Definition: tag_impl.h:42
uchar ID3_V2SpecToRev(ID3_V2Spec spec)
Definition: spec.cpp:87
ID3_V2Spec ID3_VerRevToV2Spec(uchar ver, uchar rev)
Definition: spec.cpp:34
uchar ID3_V2SpecToVer(ID3_V2Spec spec)
Definition: spec.cpp:66