/* libpgm2.c - pgm utility library part 2
**
** Copyright (C) 1989 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 "pgm.h"
#include "libpgm.h"

void
pgm_writepgminit( FILE* file, int cols, int rows, gray maxval, int forceplain )
    {
#ifdef PGM_BIGGRAYS
    if ( maxval <= 65535 && ! forceplain )
#else /* PGM_BIGGRAYS */
    if ( maxval <= 255 && ! forceplain )
#endif /* PGM_BIGGRAYS */
	fprintf(
	    file, "%c%c\n%d %d\n%d\n", PGM_MAGIC1, RPGM_MAGIC2,
	    cols, rows, maxval );
    else
	fprintf(
	    file, "%c%c\n%d %d\n%d\n", PGM_MAGIC1, PGM_MAGIC2,
	    cols, rows, maxval );
    }

static void
putus( unsigned short n, FILE* file )
    {
    if ( n >= 10 )
	putus( n / 10, file );
    (void) putc( n % 10 + '0', file );
    }

static void
pgm_writepgmrowraw( FILE* file, gray* grayrow, int cols, gray maxval )
    {
#if defined(DEBUG) || defined(PGM_BIGGRAYS)
    int col;
    gray* gP;
#endif

#ifdef DEBUG
    for ( col = 0, gP = grayrow; col < cols; ++col, ++gP )
	if ( *gP > maxval )
	    pm_error( "value out of bounds (%u > %u)", *gP, maxval );
#endif /*DEBUG*/

#ifdef PGM_BIGGRAYS
    if ( maxval > 255 )
	{
	for ( col = 0, gP = grayrow; col < cols; ++col, ++gP )
	    if ( pm_writelittleshort( file, *gP ) < 0 )
		pm_error( "write error" );
	}
    else
	if ( fwrite( grayrow, 1, cols, file ) != cols )
	    pm_error( "write error" );
#else /* PGM_BIGGRAYS */
    if ( fwrite( grayrow, 1, cols, file ) != cols )
	pm_error( "write error" );
#endif /* PGM_BIGGRAYS */
    }

static void
pgm_writepgmrowplain( FILE* file, gray* grayrow, int cols, gray maxval )
    {
    int col, charcount;
    gray* gP;

    charcount = 0;
    for ( col = 0, gP = grayrow; col < cols; ++col, ++gP )
	{
	if ( charcount >= 65 )
	    {
	    (void) putc( '\n', file );
	    charcount = 0;
	    }
	else if ( charcount > 0 )
	    {
	    (void) putc( ' ', file );
	    ++charcount;
	    }
#ifdef DEBUG
	if ( *gP > maxval )
	    pm_error( "value out of bounds (%u > %u)", *gP, maxval );
#endif /*DEBUG*/
	putus( (unsigned long) *gP, file );
	charcount += 3;
	}
    if ( charcount > 0 )
	(void) putc( '\n', file );
    }

void
pgm_writepgmrow( FILE* file, gray* grayrow, int cols, gray maxval, int forceplain )
    {
#ifdef PGM_BIGGRAYS
    if ( maxval <= 65535 && ! forceplain )
#else /* PGM_BIGGRAYS */
    if ( maxval <= 255 && ! forceplain )
#endif /* PGM_BIGGRAYS */
	pgm_writepgmrowraw( file, grayrow, cols, maxval );
    else
	pgm_writepgmrowplain( file, grayrow, cols, maxval );
    }

void
pgm_writepgm( FILE* file, gray** grays, int cols, int rows, gray maxval, int forceplain )
    {
    int row;

    pgm_writepgminit( file, cols, rows, maxval, forceplain );

    for ( row = 0; row < rows; ++row )
	 pgm_writepgmrow( file, grays[row], cols, maxval, forceplain );
    }