/* pbmtoybm.c - read a pbm and write a file for Bennet Yee's 'xbm' and 'face'
** programs.
**
** Written by Jamie Zawinski based on code (C) 1988 by Jef Poskanzer.
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation.  This software is provided "as is" without express or
** implied warranty.
*/

#include <stdio.h>
#include "pbm.h"

#define YBM_MAGIC  ( ( '!' << 8 ) | '!' )

static void putinit ARGS(( int cols, int rows ));
static void putbit ARGS(( bit b ));
static void putrest ARGS(( void ));
static void putitem ARGS(( void ));

int
main( argc, argv )
    int argc;
    char* argv[];
    {
    FILE* ifp;
    bit* bitrow;
    register bit* bP;
    int rows, cols, format, padright, row, col;


    pbm_init( &argc, argv );

    if ( argc > 2 )
	pm_usage( "[pbmfile]" );
    if ( argc == 2 )
	ifp = pm_openr( argv[1] );
    else
	ifp = stdin;

    pbm_readpbminit( ifp, &cols, &rows, &format );
    bitrow = pbm_allocrow( cols );
    
    /* Compute padding to round cols up to the nearest multiple of 16. */
    padright = ( ( cols + 15 ) / 16 ) * 16 - cols;

    putinit( cols, rows );
    for ( row = 0; row < rows; ++row )
	{
	pbm_readpbmrow( ifp, bitrow, cols, format );
        for ( col = 0, bP = bitrow; col < cols; ++col, ++bP )
	    putbit( *bP );
	for ( col = 0; col < padright; ++col )
	    putbit( 0 );
        }

    if ( ifp != stdin )
	fclose( ifp );

    putrest( );

    exit( 0 );
    }

static long item;
static int bitsperitem, bitshift;

static void
putinit( cols, rows )
    int cols, rows;
    {
    pm_writebigshort( stdout, YBM_MAGIC );
    pm_writebigshort( stdout, cols );
    pm_writebigshort( stdout, rows );
    item = 0;
    bitsperitem = 0;
    bitshift = 0;
    }

static void
putbit( bit b )
    {
    if ( bitsperitem == 16 )
	putitem( );
    ++bitsperitem;
    if ( b == PBM_BLACK )
	item += 1 << bitshift;
    ++bitshift;
    }

static void
putrest( )
    {
    if ( bitsperitem > 0 )
	putitem( );
    }

static void
putitem( )
    {
    pm_writebigshort( stdout, item );
    item = 0;
    bitsperitem = 0;
    bitshift = 0;
    }