PeerCast.root/PeerCast_1/core/common/atom.h

   1 // ------------------------------------------------
   2 // File : atom.h
   3 // Date: 1-mar-2004
   4 // Author: giles
   5 //
   6 // (c) 2002-4 peercast.org
   7 // ------------------------------------------------
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 2 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17 // ------------------------------------------------
  18
  19 #ifndef _ATOM_H
  20 #define _ATOM_H
  21
  22 #include "stream.h"
  23
  24 #include "id.h"
  25
  26 // ------------------------------------------------
  27 class AtomStream
  28 {
  29 public:
  30         AtomStream(Stream &s) : io(s),numChildren(0),numData(0)
  31         {}
  32
  33         void checkData(int d)
  34         {
  35                 if (numData != d)
  36                         throw StreamException("Bad atom data");
  37         }
  38
  39         void writeParent(ID4 id,int nc)
  40         {
  41                 io.writeID4(id);
  42                 io.writeInt(nc|0x80000000);
  43         }
  44
  45         void writeInt(ID4 id,int d)
  46         {
  47                 io.writeID4(id);
  48                 io.writeInt(4);
  49                 io.writeInt(d);
  50         }
  51
  52         void writeID4(ID4 id,ID4 d)
  53         {
  54                 io.writeID4(id);
  55                 io.writeInt(4);
  56                 io.writeID4(d);
  57         }
  58
  59         void writeShort(ID4 id,short d)
  60         {
  61                 io.writeID4(id);
  62                 io.writeInt(2);
  63                 io.writeShort(d);
  64         }
  65
  66         void writeChar(ID4 id,char d)
  67         {
  68                 io.writeID4(id);
  69                 io.writeInt(1);
  70                 io.writeChar(d);
  71         }
  72
  73         void writeBytes(ID4 id,const void *p,int l)
  74         {
  75                 io.writeID4(id);
  76                 io.writeInt(l);
  77                 io.write(p,l);
  78         }
  79
  80
  81         int writeStream(ID4 id,Stream &in,int l)
  82         {
  83                 io.writeID4(id);
  84                 io.writeInt(l);
  85                 in.writeTo(io,l);
  86                 return (sizeof(int)*2)+l;
  87
  88         }
  89
  90         void writeString(ID4 id,const char *p)
  91         {
  92                 writeBytes(id,p,strlen(p)+1);
  93         }
  94
  95         ID4     read(int &numc,int &dlen)
  96         {
  97                 ID4 id = io.readID4();
  98
  99                 unsigned int v = io.readInt();
 100                 if (v & 0x80000000)
 101                 {
 102                         numc = v&0x7fffffff;
 103                         dlen = 0;
 104                 }else
 105                 {
 106                         numc = 0;
 107                         dlen = v;
 108                 }
 109
 110                 numChildren = numc;
 111                 numData = dlen;
 112
 113                 return id;
 114         }
 115
 116         void skip(int c, int d)
 117         {
 118                 if (d)
 119                         io.skip(d);
 120
 121                 for(int i=0; i<c; i++)
 122                 {
 123                         int numc,data;
 124                         read(numc,data);
 125                         skip(numc,data);
 126                 }
 127
 128         }
 129
 130         int             readInt()
 131         {
 132                 checkData(4);
 133                 return io.readInt();
 134         }
 135         int             readID4()
 136         {
 137                 checkData(4);
 138                 return io.readID4();
 139         }
 140
 141         int             readShort()
 142         {
 143                 checkData(2);
 144                 return io.readShort();
 145         }
 146         int             readChar()
 147         {
 148                 checkData(1);
 149                 return io.readChar();
 150         }
 151         int             readBytes(void *p,int l)
 152         {
 153                 checkData(l);
 154                 return io.read(p,l);
 155         }
 156
 157         void    readString(char *s,int max,int dlen)
 158         {
 159                 checkData(dlen);
 160                 readBytes(s,max,dlen);
 161                 s[max-1] = 0;
 162
 163         }
 164
 165         void    readBytes(void *s,int max,int dlen)
 166         {
 167                 checkData(dlen);
 168                 if (max > dlen)
 169                         readBytes(s,dlen);
 170                 else
 171                 {
 172                         readBytes(s,max);
 173                         io.skip(dlen-max);
 174                 }
 175         }
 176
 177         int             writeAtoms(ID4 id, Stream &in, int cnt, int data)
 178         {
 179                 int total=0;
 180
 181                 if (cnt)
 182                 {
 183                         writeParent(id,cnt);
 184                         total+=sizeof(int)*2;
 185
 186                         for(int i=0; i<cnt; i++)
 187                         {
 188                                 AtomStream ain(in);
 189                                 int c,d;
 190                                 ID4 cid = ain.read(c,d);
 191                                 total += writeAtoms(cid,in,c,d);
 192                         }
 193                 }else
 194                 {
 195                         total += writeStream(id,in,data);
 196                 }
 197
 198                 return total;
 199         }
 200
 201         bool    eof() {return io.eof();}
 202
 203
 204         int     numChildren,numData;
 205         Stream &io;
 206 };
 207
 208 #endif