id3lib
3.8.3
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00001 // $Id: frame_render.cpp,v 1.27 2002/07/31 13:45:18 t1mpy Exp $ 00002 00003 // id3lib: a C++ library for creating and manipulating id3v1/v2 tags 00004 // Copyright 1999, 2000 Scott Thomas Haug 00005 // Copyright 2002 Thijmen Klok (thijmen@id3lib.org) 00006 00007 // This library is free software; you can redistribute it and/or modify it 00008 // under the terms of the GNU Library General Public License as published by 00009 // the Free Software Foundation; either version 2 of the License, or (at your 00010 // option) any later version. 00011 // 00012 // This library is distributed in the hope that it will be useful, but WITHOUT 00013 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 00014 // FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public 00015 // License for more details. 00016 // 00017 // You should have received a copy of the GNU Library General Public License 00018 // along with this library; if not, write to the Free Software Foundation, 00019 // Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 00020 00021 // The id3lib authors encourage improvements and optimisations to be sent to 00022 // the id3lib coordinator. Please see the README file for details on where to 00023 // send such submissions. See the AUTHORS file for a list of people who have 00024 // contributed to id3lib. See the ChangeLog file for a list of changes to 00025 // id3lib. These files are distributed with id3lib at 00026 // http://download.sourceforge.net/id3lib/ 00027 00028 #if defined HAVE_CONFIG_H 00029 #include <config.h> 00030 #endif 00031 00032 00033 00034 //#include <string.h> 00035 #include <memory.h> 00036 #include <zlib.h> 00037 00038 #include "tag.h" 00039 #include "frame_impl.h" 00040 #include "id3/io_decorators.h" //has "readers.h" "io_helpers.h" "utils.h" 00041 #include "io_strings.h" 00042 #include "io_helpers.h" 00043 00044 using namespace dami; 00045 00046 namespace 00047 { 00048 void renderFields(ID3_Writer& writer, const ID3_FrameImpl& frame) 00049 { 00050 ID3_TextEnc enc = ID3TE_ASCII; 00051 for (ID3_FrameImpl::const_iterator fi = frame.begin(); fi != frame.end(); ++fi) 00052 { 00053 ID3_Field* fld = *fi; 00054 if (fld != NULL && fld->InScope(frame.GetSpec())) 00055 { 00056 if (fld->GetID() == ID3FN_TEXTENC) 00057 { 00058 enc = static_cast<ID3_TextEnc>(fld->Get()); 00059 ID3D_NOTICE( "id3::v2::renderFields(): found encoding = " << enc ); 00060 } 00061 else 00062 { 00063 fld->SetEncoding(enc); 00064 } 00065 fld->Render(writer); 00066 } 00067 } 00068 } 00069 } 00070 00071 void ID3_FrameImpl::Render(ID3_Writer& writer) const 00072 { 00073 // Return immediately if we have no fields, which (usually) means we're 00074 // trying to render a frame which has been Cleared or hasn't been initialized 00075 if (!this->NumFields()) 00076 { 00077 return; 00078 } 00079 00080 ID3_FrameHeader hdr; 00081 00082 const size_t hdr_size = hdr.Size(); 00083 00084 // 1. Write out the field data to the buffer, with the assumption that 00085 // we won't be decompressing, since this is the usual behavior 00086 String flds; 00087 io::StringWriter fldWriter(flds); 00088 size_t origSize = 0; 00089 if (!this->GetCompression()) 00090 { 00091 renderFields(fldWriter, *this); 00092 origSize = flds.size(); 00093 ID3D_NOTICE ( "ID3_FrameImpl::Render(): uncompressed fields" ); 00094 } 00095 else 00096 { 00097 io::CompressedWriter cr(fldWriter); 00098 renderFields(cr, *this); 00099 cr.flush(); 00100 origSize = cr.getOrigSize(); 00101 ID3D_NOTICE ( "ID3_FrameImpl::Render(): compressed fields, orig size = " << 00102 origSize ); 00103 } 00104 00105 size_t fldSize = flds.size(); 00106 ID3D_NOTICE ( "ID3_FrameImpl::Render(): field size = " << fldSize ); 00107 // No need to not write empty frames, why would we not? They can be used to fill up padding space 00108 // which is even recommended in the id3 spec. 00109 // if (fldSize == 0) 00110 // { 00111 // ID3D_WARNING ( "ID3_FrameImpl::Render(): no field data" ); 00112 // return; 00113 // } 00114 00115 // determine which flags need to be set 00116 uchar eID = this->GetEncryptionID(), gID = this->GetGroupingID(); 00117 ID3_FrameID fid = this->GetID(); 00118 if (fid == ID3FID_NOFRAME) 00119 { 00120 const char *tid = this->GetTextID(); 00121 hdr.SetUnknownFrame(tid); 00122 } 00123 else 00124 { 00125 hdr.SetFrameID(fid); 00126 } 00127 hdr.SetEncryption(eID > 0); 00128 hdr.SetGrouping(gID > 0); 00129 hdr.SetCompression(origSize > fldSize); 00130 hdr.SetDataSize(fldSize + ((hdr.GetCompression() ? 4 : 0) + 00131 (hdr.GetEncryption() ? 1 : 0) + 00132 (hdr.GetGrouping() ? 1 : 0))); 00133 00134 // write out the header 00135 hdr.Render(writer); 00136 00137 if (fldSize != 0) 00138 { 00139 // No-man's land! Not part of the header, not part of the data 00140 if (hdr.GetCompression()) 00141 { 00142 io::writeBENumber(writer, origSize, sizeof(uint32)); 00143 ID3D_NOTICE( "ID3_FrameImpl::Render(): frame is compressed, wrote origSize = " << origSize ); 00144 } 00145 if (hdr.GetEncryption()) 00146 { 00147 writer.writeChar(eID); 00148 ID3D_NOTICE( "ID3_FrameImpl::Render(): frame is compressed, encryption id = " << eID ); 00149 } 00150 if (hdr.GetGrouping()) 00151 { 00152 writer.writeChar(gID); 00153 ID3D_NOTICE( "ID3_FrameImpl::Render(): frame is compressed, grouping id = " << gID ); 00154 } 00155 00156 // Write the field data 00157 writer.writeChars(flds.data(), fldSize); 00158 } 00159 _changed = false; 00160 } 00161