// disect
//
// This is a Unix program for preprocessing and splitting a source file up into
// multiple target files.  Invoke it with "disect source-file-name".  It 
// does not use standard input or standard output.  First "m4" is invoked
// on the source file, yielding a temporary file, the "modified source file".
// Then, in the modified source file, a line of the form:
//                 |-> file_1,file_2,...,file_n
// (starting in column 1) causes subsequent lines in the modified source file 
// to be copied (in duplicate) to the files file_1,...,file_n.  This rule holds 
// until another |-> directive is encountered.  Note the following 
// clarifications:
//
//       1.  Lines in the modified source file prior to the first directive 
//           are ignored.
//
//       2.  If a file name appears in multiple directives, the file will be
//           written to more than once, appending at each stage.  However,
//           initially the file contents are purged.
//
//       3.  The "|->" must appear in the first three columns.  Thereafter,
//           white space in the directive is ignored, up to the end of line.
//
//       4.  A directive may refer to between 0 and 100 files.
//
//       5.  Directives are not written to any file.
//
//       6.  Input lines longer than 5000 characters will cause trouble.
//           File names appearing in directives should not have commas or
//           white space in them.
//
// The source code for disect is C++, and it uses the gnu C++ libraries.
// Compile with "g++ disect.cc -s -o disect".

#include <String.h>
#include <SLList.h>
#include <fstream.h>
#include <stdlib.h>
#include <stdio.h>

main( int argc, char* argv[ ] )
{    if ( argc != 2 ) 
     {    cerr << "syntax error -- use \"disect filename\"\n";
          exit(1);    }
     system("m4 -B50000 < " + String( argv[1] ) +  " > .infile");
     ifstream infile( ".infile" );
     SLList<String> known;
     SLList<ofstream*> current;
     char line[5000];
     Pix p;
     int i;
     while(1)
     {    infile.getline( line, 5000 );
          if (!infile) break;
          if ( line[0] == '|' && line[1] == '-' && line[2] == '>' )
          {    for ( Pix p = current.first( ); p != 0; current.next(p) )
               {    current(p)->close( );
                    delete current(p);    }
               current.clear( );
               String linex(line);
               linex.gsub(RXwhite, "");
               linex.del("|->");
               String files[100];
               int n = 0;
               n = split( linex, files, 100, ',' );
               for ( i = 0; i < n; i++ )
               {    for ( p = known.first( ); p != 0; known.next(p) )
                         if ( files[i] == known(p) ) break;
                    if ( p == 0 )
                    {    known.append( files[i] );
                         current.append( new ofstream( files[i] ) );    }
                    else current.append( 
                         new ofstream( files[i], ios::app ) );    }    }
          else 
               for ( Pix p = current.first( ); p != 0; current.next(p) )
                    *current(p) << line << "\n";    }
     remove(".infile");    }