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/*
* msi.c -- encoding for MSI-Plessey
*
* Copyright (c) 2000 Leonid A. Broukhis (leob@mailcom.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.
*
* 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"
/* Patterns */
static char *patterns[] = { "13", "31" };
static char *fillers[] = { "031", "131" };
static int width = 16 /* each character uses 4 patterns */,
startpos = 6 /* length of the first filler */;
/*
* Check that the text can be encoded. Returns 0 or -1.
*/
int Barcode_msi_verify(unsigned char *text)
{
int i;
if (!strlen(text))
return -1;
for (i=0; text[i]; i++) {
if (!isdigit(text[i]))
return -1;
}
return 0;
}
static int add_one(char *ptr, int code)
{
sprintf(ptr, "%s%s%s%s",
patterns[(code >> 3) & 1],
patterns[(code >> 2) & 1],
patterns[(code >> 1) & 1],
patterns[code & 1]);
return 0;
}
/*
* The encoding functions fills the "partial" and "textinfo" fields.
* Lowercase chars are converted to uppercase
*/
int Barcode_msi_encode(struct Barcode_Item *bc)
{
static char *text;
static char *partial; /* dynamic */
static char *textinfo; /* dynamic */
char *ptr, *textptr;
int i, code, textpos, usesum, checksum = 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("msi");
if ((bc->flags & BARCODE_NO_CHECKSUM))
usesum = 0;
else
usesum = 1;
text = bc->ascii;
/* the partial code is head + 8 * (text + check) + tail + margin + term. */
partial = malloc( 3 + 8 * (strlen(text) + 1) + 3 + 2 );
if (!partial) {
bc->error = errno;
return -1;
}
/* the text information is at most "nnn:fff:c " * strlen +term */
textinfo = malloc(10*strlen(text) + 2);
if (!textinfo) {
bc->error = errno;
free(partial);
return -1;
}
strcpy(partial, fillers[0]);
ptr = partial + strlen(partial);
textptr = textinfo;
textpos = startpos;
for (i=0; i<strlen(text); i++) {
code = text[i] - '0';
add_one(ptr, code);
sprintf(textptr, "%i:12:%c ", textpos, text[i]);
textpos += width; /* width of each code */
textptr += strlen(textptr);
ptr += strlen(ptr);
if (usesum) {
/* For a code ...FEDCBA the checksum is computed
* as the sum of digits of the number ...FDB plus
* the sum of digits of the number ...ECA * 2.
* Which is equivalent to the sum of each digit of ...ECA doubled
* plus carry.
*/
if ((i ^ strlen(text)) & 1) {
/* a last digit, 2 away from last, etc. */
checksum += 2 * code + (2 * code) / 10;
} else {
checksum += code;
}
}
}
/* Some implementations use a double checksum. Currently the only way
* to print a barcode with double checksum is to put the checksum
* digit printed below at the end of a code in the command line
* and re-run the program.
*/
if (usesum) {
/* the check digit is the complement of the checksum
* to a multiple of 10.
*/
checksum = (checksum + 9) / 10 * 10 - checksum;
/* fprintf(stderr, "Checksum: %d\n", checksum); */
add_one(ptr, checksum);
ptr += strlen(ptr);
}
strcpy(ptr, fillers[1]);
bc->partial = partial;
bc->textinfo = textinfo;
return 0;
}
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