/***************************************************************************
                       i25.cpp  -  description
                           -------------------
  begin                : Mie Jun 18 2003
  copyright            : (C) 2003 by InfoSiAL, S.L.
  email                : mail@infosial.com
***************************************************************************/ 
/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

/*
 * i25.c -- "interleaved 2 of 5"
 *
 * Copyright (c) 1999,2000 Alessandro Rubini (rubini@gnu.org)
 * Copyright (c) 1999      Prosa Srl. (prosa@prosa.it)
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>

#include "barcode.h"

static char *codes[] = {
                           "11331", "31113", "13113", "33111", "11313",
                           "31311", "13311", "11133", "31131", "13131"
                       };

static char *guard[] = { "a1a1", "c1a" };	/* begin end */

int Barcode_i25_verify( char *text ) {
	if ( !text[ 0 ] )
		return -1;
	while ( *text && isdigit( *text ) )
		text++;
	if ( *text )
		return -1;							/* a non-digit char */
	return 0;										/* ok */
}

int Barcode_i25_encode( struct Barcode_Item *bc ) {
	char *text;
	char *partial;							/* dynamic */
	char *textinfo;							/* dynamic */
	char *textptr, *p1, *p2, *pd;
	int i, len, sum[ 2 ], textpos, usesum = 0;

	if ( bc->partial )
		free( bc->partial );
	if ( bc->textinfo )
		free( bc->textinfo );
	bc->partial = bc->textinfo = NULL;	/* safe */

	if ( !bc->encoding )
		bc->encoding = strdup( "interleaved 2 of 5" );

	text = bc->ascii;
	if ( !bc->ascii ) {
		bc->error = EINVAL;
		return -1;
	}

	if ( ( bc->flags & BARCODE_NO_CHECKSUM ) )
		usesum = 0;
	else
		usesum = 1;

	/* create the real text string, padded to an even number of digits */
	text = ( char * ) malloc( strlen( bc->ascii ) + 3 );	/* leading 0, checksum, term. */
	if ( !text ) {
		bc->error = errno;
		return -1;
	}
	/* add the leading 0 if needed */
	i = strlen( bc->ascii ) + usesum;
	if ( i % 2 ) {
		/* add a leading 0 */
		text[ 0 ] = '0';
		strcpy( text + 1, bc->ascii );
	} else {
		strcpy( text, bc->ascii );
	}
	/* add the trailing checksum if needed, the leading 0 is ignored */
	if ( usesum ) {
		sum[ 0 ] = sum[ 1 ] = 0;
		for ( i = 0; text[ i ]; i++ )
			sum[ i % 2 ] += text[ i ] - '0';
		/*
		 * The "even" sum must be multiplied by three, and the *
		 * rightmost digit is defined as "even". The digits' position
		 * is already correct, whether or not we added a leading zero.
		 * (e.g., they are in pos. 0..4 or 1..4 of the string)
		 */
		i = sum[ 0 ] * 3 + sum[ 1 ];
		strcat( text, "0" );
		text[ strlen( text ) - 1 ] += ( 10 - ( i % 10 ) ) % 10;
	}

	/* the partial code is 5 * (text + check) + 4(head) + 3(tail) + term. */
	partial = ( char * ) malloc( ( strlen( text ) + 3 ) * 5 + 2 );	/* be large... */
	if ( !partial ) {
		bc->error = errno;
		free( text );
		return -1;
	}

	/* the text information is at most "nnn:fff:c " * (strlen+1) +term */
	textinfo = ( char * ) malloc( 10 * ( strlen( text ) + 1 ) + 2 );
	if ( !textinfo ) {
		bc->error = errno;
		free( partial );
		free( text );
		return -1;
	}


	strcpy( partial, "0" );				/* the first space */
	strcat( partial, guard[ 0 ] );	/* start */
	textpos = 4;								/* width of initial guard */
	textptr = textinfo;

	len = strlen( text );
	for ( i = 0; i < len; i += 2 ) {
		if ( !isdigit( text[ i ] ) || !isdigit( text[ i + 1 ] ) ) {
			bc->error = EINVAL;	/* impossible if text is verified */
			free( partial );
			free( textinfo );
			free( text );
			return -1;
		}
		/* interleave two digits */
		p1 = codes[ text[ i ] - '0' ];
		p2 = codes[ text[ i + 1 ] - '0' ];
		pd = partial + strlen( partial );	/* destination */
		while ( *p1 ) {
			*( pd++ ) = *( p1++ );
			*( pd++ ) = *( p2++ );
		}
		*pd = '\0';
		/* and print the ascii text (but don't print the checksum, if any */
		if ( usesum && strlen( text + i ) == 2 ) {
			/* print only one digit, discard the checksum */
			sprintf( textptr, "%i:12:%c ", textpos, text[ i ] );
		} else {
			sprintf( textptr, "%i:12:%c %i:12:%c ", textpos, text[ i ],
			         textpos + 9, text[ i + 1 ] );
		}
		textpos += 18;					/* width of two codes */
		textptr += strlen( textptr );
	}
	strcat( partial, guard[ 1 ] );

	bc->partial = partial;
	bc->textinfo = textinfo;
	free( text );

	return 0;
}