third-party/leptonica/src/bardecode.c
/*====================================================================*
- Copyright (C) 2001 Leptonica. All rights reserved.
-
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions
- are met:
- 1. Redistributions of source code must retain the above copyright
- notice, this list of conditions and the following disclaimer.
- 2. Redistributions in binary form must reproduce the above
- copyright notice, this list of conditions and the following
- disclaimer in the documentation and/or other materials
- provided with the distribution.
-
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY
- CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
- OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*====================================================================*/
/*
* bardecode.c
*
* Dispatcher
* char *barcodeDispatchDecoder()
*
* Format Determination
* static l_int32 barcodeFindFormat()
* l_int32 barcodeFormatIsSupported()
* static l_int32 barcodeVerifyFormat()
*
* Decode 2 of 5
* static char *barcodeDecode2of5()
*
* Decode Interleaved 2 of 5
* static char *barcodeDecodeI2of5()
*
* Decode Code 93
* static char *barcodeDecode93()
*
* Decode Code 39
* static char *barcodeDecode39()
*
* Decode Codabar
* static char *barcodeDecodeCodabar()
*
* Decode UPC-A
* static char *barcodeDecodeUpca()
*
* Decode EAN 13
* static char *barcodeDecodeEan13()
*/
#include <string.h>
#include "allheaders.h"
#include "readbarcode.h"
static l_int32 barcodeFindFormat(char *barstr);
static l_int32 barcodeVerifyFormat(char *barstr, l_int32 format,
l_int32 *pvalid, l_int32 *preverse);
static char *barcodeDecode2of5(char *barstr, l_int32 debugflag);
static char *barcodeDecodeI2of5(char *barstr, l_int32 debugflag);
static char *barcodeDecode93(char *barstr, l_int32 debugflag);
static char *barcodeDecode39(char *barstr, l_int32 debugflag);
static char *barcodeDecodeCodabar(char *barstr, l_int32 debugflag);
static char *barcodeDecodeUpca(char *barstr, l_int32 debugflag);
static char *barcodeDecodeEan13(char *barstr, l_int32 first, l_int32 debugflag);
#ifndef NO_CONSOLE_IO
#define DEBUG_CODES 0
#endif /* ~NO_CONSOLE_IO */
/*------------------------------------------------------------------------*
* Decoding dispatcher *
*------------------------------------------------------------------------*/
/*!
* barcodeDispatchDecoder()
*
* Input: barstr (string of integers in set {1,2,3,4} of bar widths)
* format (L_BF_ANY, L_BF_CODEI2OF5, L_BF_CODE93, ...)
* debugflag (use 1 to generate debug output)
* Return: data (string of decoded barcode data), or null on error
*/
char *
barcodeDispatchDecoder(char *barstr,
l_int32 format,
l_int32 debugflag)
{
char *data = NULL;
PROCNAME("barcodeDispatchDecoder");
if (!barstr)
return (char *)ERROR_PTR("barstr not defined", procName, NULL);
debugflag = FALSE; /* not used yet */
if (format == L_BF_ANY)
format = barcodeFindFormat(barstr);
if (format == L_BF_CODE2OF5)
data = barcodeDecode2of5(barstr, debugflag);
else if (format == L_BF_CODEI2OF5)
data = barcodeDecodeI2of5(barstr, debugflag);
else if (format == L_BF_CODE93)
data = barcodeDecode93(barstr, debugflag);
else if (format == L_BF_CODE39)
data = barcodeDecode39(barstr, debugflag);
else if (format == L_BF_CODABAR)
data = barcodeDecodeCodabar(barstr, debugflag);
else if (format == L_BF_UPCA)
data = barcodeDecodeUpca(barstr, debugflag);
else if (format == L_BF_EAN13)
data = barcodeDecodeEan13(barstr, 0, debugflag);
else
return (char *)ERROR_PTR("format not implemented", procName, NULL);
return data;
}
/*------------------------------------------------------------------------*
* Barcode format determination *
*------------------------------------------------------------------------*/
/*!
* barcodeFindFormat()
*
* Input: barstr (of barcode widths, in set {1,2,3,4})
* Return: format (for barcode), or L_BF_UNKNOWN if not recognized
*/
static l_int32
barcodeFindFormat(char *barstr)
{
l_int32 i, format, valid;
PROCNAME("barcodeFindFormat");
if (!barstr)
return ERROR_INT("barstr not defined", procName, L_BF_UNKNOWN);
for (i = 0; i < NumSupportedBarcodeFormats; i++) {
format = SupportedBarcodeFormat[i];
barcodeVerifyFormat(barstr, format, &valid, NULL);
if (valid) {
L_INFO("Barcode format: %s\n", procName,
SupportedBarcodeFormatName[i]);
return format;
}
}
return L_BF_UNKNOWN;
}
/*!
* barcodeFormatIsSupported()
*
* Input: format
* Return: 1 if format is one of those supported; 0 otherwise
*
*/
l_int32
barcodeFormatIsSupported(l_int32 format)
{
l_int32 i;
for (i = 0; i < NumSupportedBarcodeFormats; i++) {
if (format == SupportedBarcodeFormat[i])
return 1;
}
return 0;
}
/*!
* barcodeVerifyFormat()
*
* Input: barstr (of barcode widths, in set {1,2,3,4})
* format (L_BF_CODEI2OF5, L_BF_CODE93, ...)
* &valid (<return> 0 if not valid, 1 and 2 if valid)
* &reverse (<optional return> 1 if reversed; 0 otherwise)
* Return: 0 if OK, 1 on error
*
* Notes:
* (1) If valid == 1, the barcode is of the given format in the
* forward order; if valid == 2, it is backwards.
* (2) If the barcode needs to be reversed to read it, and &reverse
* is provided, a 1 is put into @reverse.
* (3) Add to this as more formats are supported.
*/
static l_int32
barcodeVerifyFormat(char *barstr,
l_int32 format,
l_int32 *pvalid,
l_int32 *preverse)
{
char *revbarstr;
l_int32 i, start, len, stop, mid;
PROCNAME("barcodeVerifyFormat");
if (!pvalid)
return ERROR_INT("barstr not defined", procName, 1);
*pvalid = 0;
if (preverse) *preverse = 0;
if (!barstr)
return ERROR_INT("barstr not defined", procName, 1);
switch (format)
{
case L_BF_CODE2OF5:
start = !strncmp(barstr, Code2of5[C25_START], 3);
len = strlen(barstr);
stop = !strncmp(&barstr[len - 5], Code2of5[C25_STOP], 5);
if (start && stop) {
*pvalid = 1;
} else {
revbarstr = stringReverse(barstr);
start = !strncmp(revbarstr, Code2of5[C25_START], 3);
stop = !strncmp(&revbarstr[len - 5], Code2of5[C25_STOP], 5);
FREE(revbarstr);
if (start && stop) {
*pvalid = 1;
if (preverse) *preverse = 1;
}
}
break;
case L_BF_CODEI2OF5:
start = !strncmp(barstr, CodeI2of5[CI25_START], 4);
len = strlen(barstr);
stop = !strncmp(&barstr[len - 3], CodeI2of5[CI25_STOP], 3);
if (start && stop) {
*pvalid = 1;
} else {
revbarstr = stringReverse(barstr);
start = !strncmp(revbarstr, CodeI2of5[CI25_START], 4);
stop = !strncmp(&revbarstr[len - 3], CodeI2of5[CI25_STOP], 3);
FREE(revbarstr);
if (start && stop) {
*pvalid = 1;
if (preverse) *preverse = 1;
}
}
break;
case L_BF_CODE93:
start = !strncmp(barstr, Code93[C93_START], 6);
len = strlen(barstr);
stop = !strncmp(&barstr[len - 7], Code93[C93_STOP], 6);
if (start && stop) {
*pvalid = 1;
} else {
revbarstr = stringReverse(barstr);
start = !strncmp(revbarstr, Code93[C93_START], 6);
stop = !strncmp(&revbarstr[len - 7], Code93[C93_STOP], 6);
FREE(revbarstr);
if (start && stop) {
*pvalid = 1;
if (preverse) *preverse = 1;
}
}
break;
case L_BF_CODE39:
start = !strncmp(barstr, Code39[C39_START], 9);
len = strlen(barstr);
stop = !strncmp(&barstr[len - 9], Code39[C39_STOP], 9);
if (start && stop) {
*pvalid = 1;
} else {
revbarstr = stringReverse(barstr);
start = !strncmp(revbarstr, Code39[C39_START], 9);
stop = !strncmp(&revbarstr[len - 9], Code39[C39_STOP], 9);
FREE(revbarstr);
if (start && stop) {
*pvalid = 1;
if (preverse) *preverse = 1;
}
}
break;
case L_BF_CODABAR:
start = stop = 0;
len = strlen(barstr);
for (i = 16; i <= 19; i++) /* any of these will do */
start += !strncmp(barstr, Codabar[i], 7);
for (i = 16; i <= 19; i++) /* ditto */
stop += !strncmp(&barstr[len - 7], Codabar[i], 7);
if (start && stop) {
*pvalid = 1;
} else {
start = stop = 0;
revbarstr = stringReverse(barstr);
for (i = 16; i <= 19; i++)
start += !strncmp(revbarstr, Codabar[i], 7);
for (i = 16; i <= 19; i++)
stop += !strncmp(&revbarstr[len - 7], Codabar[i], 7);
FREE(revbarstr);
if (start && stop) {
*pvalid = 1;
if (preverse) *preverse = 1;
}
}
break;
case L_BF_UPCA:
case L_BF_EAN13:
len = strlen(barstr);
if (len == 59) {
start = !strncmp(barstr, Upca[UPCA_START], 3);
mid = !strncmp(&barstr[27], Upca[UPCA_MID], 5);
stop = !strncmp(&barstr[len - 3], Upca[UPCA_STOP], 3);
if (start && mid && stop)
*pvalid = 1;
}
break;
default:
return ERROR_INT("format not supported", procName, 1);
}
return 0;
}
/*------------------------------------------------------------------------*
* Code 2 of 5 *
*------------------------------------------------------------------------*/
/*!
* barcodeDecode2of5()
*
* Input: barstr (of widths, in set {1, 2})
* debugflag
* Return: data (string of digits), or null if none found or on error
*
* Notes:
* (1) Ref: http://en.wikipedia.org/wiki/Two-out-of-five_code (Note:
* the codes given here are wrong!)
* http://morovia.com/education/symbology/code25.asp
* (2) This is a very low density encoding for the 10 digits.
* Each digit is encoded with 5 black bars, of which 2 are wide
* and 3 are narrow. No information is carried in the spaces
* between the bars, which are all equal in width, represented by
* a "1" in our encoding.
* (3) The mapping from the sequence of five bar widths to the
* digit is identical to the mapping used by the interleaved
* 2 of 5 code. The start code is 21211, representing two
* wide bars and a narrow bar, and the interleaved "1" spaces
* are explicit. The stop code is 21112. For all codes
* (including start and stop), the trailing space "1" is
* implicit -- there is no reason to represent it in the
* Code2of5[] array.
*/
static char *
barcodeDecode2of5(char *barstr,
l_int32 debugflag)
{
char *data, *vbarstr;
char code[10];
l_int32 valid, reverse, i, j, len, error, ndigits, start, found;
PROCNAME("barcodeDecodeI2of5");
if (!barstr)
return (char *)ERROR_PTR("barstr not defined", procName, NULL);
/* Verify format; reverse if necessary */
barcodeVerifyFormat(barstr, L_BF_CODE2OF5, &valid, &reverse);
if (!valid)
return (char *)ERROR_PTR("barstr not in 2of5 format", procName, NULL);
if (reverse)
vbarstr = stringReverse(barstr);
else
vbarstr = stringNew(barstr);
/* Verify size */
len = strlen(vbarstr);
if ((len - 11) % 10 != 0)
return (char *)ERROR_PTR("size not divisible by 10: invalid 2of5 code",
procName, NULL);
error = FALSE;
ndigits = (len - 11) / 10;
data = (char *)CALLOC(ndigits + 1, sizeof(char));
memset(code, 0, 10);
for (i = 0; i < ndigits; i++) {
start = 6 + 10 * i;
for (j = 0; j < 9; j++)
code[j] = vbarstr[start + j];
if (debugflag)
fprintf(stderr, "code: %s\n", code);
found = FALSE;
for (j = 0; j < 10; j++) {
if (!strcmp(code, Code2of5[j])) {
data[i] = 0x30 + j;
found = TRUE;
break;
}
}
if (!found) error = TRUE;
}
FREE(vbarstr);
if (error) {
FREE(data);
return (char *)ERROR_PTR("error in decoding", procName, NULL);
}
return data;
}
/*------------------------------------------------------------------------*
* Interleaved Code 2 of 5 *
*------------------------------------------------------------------------*/
/*!
* barcodeDecodeI2of5()
*
* Input: barstr (of widths, in set {1, 2})
* debugflag
* Return: data (string of digits), or null if none found or on error
*
* Notes:
* (1) Ref: http://en.wikipedia.org/wiki/Interleaved_2_of_5
* (2) This always encodes an even number of digits.
* The start code is 1111; the stop code is 211.
*/
static char *
barcodeDecodeI2of5(char *barstr,
l_int32 debugflag)
{
char *data, *vbarstr;
char code1[6], code2[6];
l_int32 valid, reverse, i, j, len, error, npairs, start, found;
PROCNAME("barcodeDecodeI2of5");
if (!barstr)
return (char *)ERROR_PTR("barstr not defined", procName, NULL);
/* Verify format; reverse if necessary */
barcodeVerifyFormat(barstr, L_BF_CODEI2OF5, &valid, &reverse);
if (!valid)
return (char *)ERROR_PTR("barstr not in i2of5 format", procName, NULL);
if (reverse)
vbarstr = stringReverse(barstr);
else
vbarstr = stringNew(barstr);
/* Verify size */
len = strlen(vbarstr);
if ((len - 7) % 10 != 0)
return (char *)ERROR_PTR("size not divisible by 10: invalid I2of5 code",
procName, NULL);
error = FALSE;
npairs = (len - 7) / 10;
data = (char *)CALLOC(2 * npairs + 1, sizeof(char));
memset(code1, 0, 6);
memset(code2, 0, 6);
for (i = 0; i < npairs; i++) {
start = 4 + 10 * i;
for (j = 0; j < 5; j++) {
code1[j] = vbarstr[start + 2 * j];
code2[j] = vbarstr[start + 2 * j + 1];
}
if (debugflag)
fprintf(stderr, "code1: %s, code2: %s\n", code1, code2);
found = FALSE;
for (j = 0; j < 10; j++) {
if (!strcmp(code1, CodeI2of5[j])) {
data[2 * i] = 0x30 + j;
found = TRUE;
break;
}
}
if (!found) error = TRUE;
found = FALSE;
for (j = 0; j < 10; j++) {
if (!strcmp(code2, CodeI2of5[j])) {
data[2 * i + 1] = 0x30 + j;
found = TRUE;
break;
}
}
if (!found) error = TRUE;
}
FREE(vbarstr);
if (error) {
FREE(data);
return (char *)ERROR_PTR("error in decoding", procName, NULL);
}
return data;
}
/*------------------------------------------------------------------------*
* Code 93 *
*------------------------------------------------------------------------*/
/*!
* barcodeDecode93()
*
* Input: barstr (of widths, in set {1, 2, 3, 4})
* debugflag
* Return: data (string of digits), or null if none found or on error
*
* Notes:
* (1) Ref: http://en.wikipedia.org/wiki/Code93
* http://morovia.com/education/symbology/code93.asp
* (2) Each symbol has 3 black and 3 white bars.
* The start and stop codes are 111141; the stop code then is
* terminated with a final (1) bar.
* (3) The last two codes are check codes. We are checking them
* for correctness, and issuing a warning on failure. Should
* probably not return any data on failure.
*/
static char *
barcodeDecode93(char *barstr,
l_int32 debugflag)
{
const char *checkc, *checkk;
char *data, *vbarstr;
char code[7];
l_int32 valid, reverse, i, j, len, error, nsymb, start, found, sum;
l_int32 *index;
PROCNAME("barcodeDecode93");
if (!barstr)
return (char *)ERROR_PTR("barstr not defined", procName, NULL);
/* Verify format; reverse if necessary */
barcodeVerifyFormat(barstr, L_BF_CODE93, &valid, &reverse);
if (!valid)
return (char *)ERROR_PTR("barstr not in code93 format", procName, NULL);
if (reverse)
vbarstr = stringReverse(barstr);
else
vbarstr = stringNew(barstr);
/* Verify size; skip the first 6 and last 7 bars. */
len = strlen(vbarstr);
if ((len - 13) % 6 != 0)
return (char *)ERROR_PTR("size not divisible by 6: invalid code 93",
procName, NULL);
/* Decode the symbols */
nsymb = (len - 13) / 6;
data = (char *)CALLOC(nsymb + 1, sizeof(char));
index = (l_int32 *)CALLOC(nsymb, sizeof(l_int32));
memset(code, 0, 7);
error = FALSE;
for (i = 0; i < nsymb; i++) {
start = 6 + 6 * i;
for (j = 0; j < 6; j++)
code[j] = vbarstr[start + j];
if (debugflag)
fprintf(stderr, "code: %s\n", code);
found = FALSE;
for (j = 0; j < C93_START; j++) {
if (!strcmp(code, Code93[j])) {
data[i] = Code93Val[j];
index[i] = j;
found = TRUE;
break;
}
}
if (!found) error = TRUE;
}
FREE(vbarstr);
if (error) {
FREE(index);
FREE(data);
return (char *)ERROR_PTR("error in decoding", procName, NULL);
}
/* Do check sums. For character "C", use only the
* actual data in computing the sum. For character "K",
* use the actual data plus the check character "C". */
sum = 0;
for (i = 0; i < nsymb - 2; i++) /* skip the "C" and "K" */
sum += ((i % 20) + 1) * index[nsymb - 3 - i];
if (data[nsymb - 2] != Code93Val[sum % 47])
L_WARNING("Error for check C\n", procName);
if (debugflag) {
checkc = Code93[sum % 47];
fprintf(stderr, "checkc = %s\n", checkc);
}
sum = 0;
for (i = 0; i < nsymb - 1; i++) /* skip the "K" */
sum += ((i % 15) + 1) * index[nsymb - 2 - i];
if (data[nsymb - 1] != Code93Val[sum % 47])
L_WARNING("Error for check K\n", procName);
if (debugflag) {
checkk = Code93[sum % 47];
fprintf(stderr, "checkk = %s\n", checkk);
}
/* Remove the two check codes from the output */
data[nsymb - 2] = '\0';
FREE(index);
return data;
}
/*------------------------------------------------------------------------*
* Code 39 *
*------------------------------------------------------------------------*/
/*!
* barcodeDecode39()
*
* Input: barstr (of widths, in set {1, 2})
* debugflag
* Return: data (string of digits), or null if none found or on error
*
* Notes:
* (1) Ref: http://en.wikipedia.org/wiki/Code39
* http://morovia.com/education/symbology/code39.asp
* (2) Each symbol has 5 black and 4 white bars.
* The start and stop codes are 121121211 (the asterisk)
* (3) This decoder was contributed by Roger Hyde.
*/
static char *
barcodeDecode39(char *barstr,
l_int32 debugflag)
{
char *data, *vbarstr;
char code[10];
l_int32 valid, reverse, i, j, len, error, nsymb, start, found;
PROCNAME("barcodeDecode39");
if (!barstr)
return (char *)ERROR_PTR("barstr not defined", procName, NULL);
/* Verify format; reverse if necessary */
barcodeVerifyFormat(barstr, L_BF_CODE39, &valid, &reverse);
if (!valid)
return (char *)ERROR_PTR("barstr not in code39 format", procName, NULL);
if (reverse)
vbarstr = stringReverse(barstr);
else
vbarstr = stringNew(barstr);
/* Verify size */
len = strlen(vbarstr);
if ((len + 1) % 10 != 0)
return (char *)ERROR_PTR("size+1 not divisible by 10: invalid code 39",
procName, NULL);
/* Decode the symbols */
nsymb = (len - 19) / 10;
data = (char *)CALLOC(nsymb + 1, sizeof(char));
memset(code, 0, 10);
error = FALSE;
for (i = 0; i < nsymb; i++) {
start = 10 + 10 * i;
for (j = 0; j < 9; j++)
code[j] = vbarstr[start + j];
if (debugflag)
fprintf(stderr, "code: %s\n", code);
found = FALSE;
for (j = 0; j < C39_START; j++) {
if (!strcmp(code, Code39[j])) {
data[i] = Code39Val[j];
found = TRUE;
break;
}
}
if (!found) error = TRUE;
}
FREE(vbarstr);
if (error) {
FREE(data);
return (char *)ERROR_PTR("error in decoding", procName, NULL);
}
return data;
}
/*------------------------------------------------------------------------*
* Codabar *
*------------------------------------------------------------------------*/
/*!
* barcodeDecodeCodabar()
*
* Input: barstr (of widths, in set {1, 2})
* debugflag
* Return: data (string of digits), or null if none found or on error
*
* Notes:
* (1) Ref: http://en.wikipedia.org/wiki/Codabar
* http://morovia.com/education/symbology/codabar.asp
* (2) Each symbol has 4 black and 3 white bars. They represent the
* 10 digits, and optionally 6 other characters. The start and
* stop codes can be any of four (typically denoted A,B,C,D).
*/
static char *
barcodeDecodeCodabar(char *barstr,
l_int32 debugflag)
{
char *data, *vbarstr;
char code[8];
l_int32 valid, reverse, i, j, len, error, nsymb, start, found;
PROCNAME("barcodeDecodeCodabar");
if (!barstr)
return (char *)ERROR_PTR("barstr not defined", procName, NULL);
/* Verify format; reverse if necessary */
barcodeVerifyFormat(barstr, L_BF_CODABAR, &valid, &reverse);
if (!valid)
return (char *)ERROR_PTR("barstr not in codabar format",
procName, NULL);
if (reverse)
vbarstr = stringReverse(barstr);
else
vbarstr = stringNew(barstr);
/* Verify size */
len = strlen(vbarstr);
if ((len + 1) % 8 != 0)
return (char *)ERROR_PTR("size+1 not divisible by 8: invalid codabar",
procName, NULL);
/* Decode the symbols */
nsymb = (len - 15) / 8;
data = (char *)CALLOC(nsymb + 1, sizeof(char));
memset(code, 0, 8);
error = FALSE;
for (i = 0; i < nsymb; i++) {
start = 8 + 8 * i;
for (j = 0; j < 7; j++)
code[j] = vbarstr[start + j];
if (debugflag)
fprintf(stderr, "code: %s\n", code);
found = FALSE;
for (j = 0; j < 16; j++) {
if (!strcmp(code, Codabar[j])) {
data[i] = CodabarVal[j];
found = TRUE;
break;
}
}
if (!found) error = TRUE;
}
FREE(vbarstr);
if (error) {
FREE(data);
return (char *)ERROR_PTR("error in decoding", procName, NULL);
}
return data;
}
/*------------------------------------------------------------------------*
* Code UPC-A *
*------------------------------------------------------------------------*/
/*!
* barcodeDecodeUpca()
*
* Input: barstr (of widths, in set {1, 2, 3, 4})
* debugflag
* Return: data (string of digits), or null if none found or on error
*
* Notes:
* (1) Ref: http://en.wikipedia.org/wiki/UniversalProductCode
* http://morovia.com/education/symbology/upc-a.asp
* (2) Each symbol has 2 black and 2 white bars, and encodes a digit.
* The start and stop codes are 111 and 111. There are a total of
* 30 black bars, encoding 12 digits in two sets of 6, with
* 2 black bars separating the sets.
* (3) The last digit is a check digit. We check for correctness, and
* issue a warning on failure. Should probably not return any
* data on failure.
*/
static char *
barcodeDecodeUpca(char *barstr,
l_int32 debugflag)
{
char *data, *vbarstr;
char code[5];
l_int32 valid, i, j, len, error, start, found, sum, checkdigit;
PROCNAME("barcodeDecodeUpca");
if (!barstr)
return (char *)ERROR_PTR("barstr not defined", procName, NULL);
/* Verify format; reverse has no meaning here -- we must test both */
barcodeVerifyFormat(barstr, L_BF_UPCA, &valid, NULL);
if (!valid)
return (char *)ERROR_PTR("barstr not in UPC-A format", procName, NULL);
/* Verify size */
len = strlen(barstr);
if (len != 59)
return (char *)ERROR_PTR("size not 59; invalid UPC-A barcode",
procName, NULL);
/* Check the first digit. If invalid, reverse the string. */
memset(code, 0, 5);
for (i = 0; i < 4; i++)
code[i] = barstr[i + 3];
found = FALSE;
for (i = 0; i < 10; i++) {
if (!strcmp(code, Upca[i])) {
found = TRUE;
break;
}
}
if (found == FALSE)
vbarstr = stringReverse(barstr);
else
vbarstr = stringNew(barstr);
/* Decode the 12 symbols */
data = (char *)CALLOC(13, sizeof(char));
memset(code, 0, 5);
error = FALSE;
for (i = 0; i < 12; i++) {
if (i < 6)
start = 3 + 4 * i;
else
start = 32 + 4 * (i - 6);
for (j = 0; j < 4; j++)
code[j] = vbarstr[start + j];
if (debugflag)
fprintf(stderr, "code: %s\n", code);
found = FALSE;
for (j = 0; j < 10; j++) {
if (!strcmp(code, Upca[j])) {
data[i] = 0x30 + j;
found = TRUE;
break;
}
}
if (!found) error = TRUE;
}
FREE(vbarstr);
if (error) {
FREE(data);
return (char *)ERROR_PTR("error in decoding", procName, NULL);
}
/* Calculate the check digit (data[11]). */
sum = 0;
for (i = 0; i < 12; i += 2) /* "even" digits */
sum += 3 * (data[i] - 0x30);
for (i = 1; i < 11; i += 2) /* "odd" digits */
sum += (data[i] - 0x30);
checkdigit = sum % 10;
if (checkdigit) /* not 0 */
checkdigit = 10 - checkdigit;
if (checkdigit + 0x30 != data[11])
L_WARNING("Error for UPC-A check character\n", procName);
return data;
}
/*------------------------------------------------------------------------*
* Code EAN-13 *
*------------------------------------------------------------------------*/
/*!
* barcodeDecodeEan13()
*
* Input: barstr (of widths, in set {1, 2, 3, 4})
* first (first digit: 0 - 9)
* debugflag
* Return: data (string of digits), or null if none found or on error
*
* Notes:
* (1) Ref: http://en.wikipedia.org/wiki/UniversalProductCode
* http://morovia.com/education/symbology/ean-13.asp
* (2) The encoding is essentially the same as UPC-A, except
* there are 13 digits in total, of which 12 are encoded
* by bars (as with UPC-A) and the 13th is a leading digit
* that determines the encoding of the next 6 digits,
* selecting each digit from one of two tables.
* encoded in the bars (as with UPC-A). If the first digit
* is 0, the encoding is identical to UPC-A.
* (3) As with UPC-A, the last digit is a check digit.
* (4) For now, we assume the first digit is input to this function.
* Eventually, we will read it by pattern matching.
*
* TODO: fix this for multiple tables, depending on the value of @first
*/
static char *
barcodeDecodeEan13(char *barstr,
l_int32 first,
l_int32 debugflag)
{
char *data, *vbarstr;
char code[5];
l_int32 valid, i, j, len, error, start, found, sum, checkdigit;
PROCNAME("barcodeDecodeEan13");
if (!barstr)
return (char *)ERROR_PTR("barstr not defined", procName, NULL);
/* Verify format. You can't tell the orientation by the start
* and stop codes, but you can by the location of the digits.
* Use the UPCA verifier for EAN 13 -- it is identical. */
barcodeVerifyFormat(barstr, L_BF_UPCA, &valid, NULL);
if (!valid)
return (char *)ERROR_PTR("barstr not in EAN 13 format", procName, NULL);
/* Verify size */
len = strlen(barstr);
if (len != 59)
return (char *)ERROR_PTR("size not 59; invalid EAN 13 barcode",
procName, NULL);
/* Check the first digit. If invalid, reverse the string. */
memset(code, 0, 5);
for (i = 0; i < 4; i++)
code[i] = barstr[i + 3];
found = FALSE;
for (i = 0; i < 10; i++) {
if (!strcmp(code, Upca[i])) {
found = TRUE;
break;
}
}
if (found == FALSE)
vbarstr = stringReverse(barstr);
else
vbarstr = stringNew(barstr);
/* Decode the 12 symbols */
data = (char *)CALLOC(13, sizeof(char));
memset(code, 0, 5);
error = FALSE;
for (i = 0; i < 12; i++) {
if (i < 6)
start = 3 + 4 * i;
else
start = 32 + 4 * (i - 6);
for (j = 0; j < 4; j++)
code[j] = vbarstr[start + j];
if (debugflag)
fprintf(stderr, "code: %s\n", code);
found = FALSE;
for (j = 0; j < 10; j++) {
if (!strcmp(code, Upca[j])) {
data[i] = 0x30 + j;
found = TRUE;
break;
}
}
if (!found) error = TRUE;
}
FREE(vbarstr);
if (error) {
FREE(data);
return (char *)ERROR_PTR("error in decoding", procName, NULL);
}
/* Calculate the check digit (data[11]). */
sum = 0;
for (i = 0; i < 12; i += 2) /* "even" digits */
sum += 3 * (data[i] - 0x30);
for (i = 1; i < 12; i += 2) /* "odd" digits */
sum += (data[i] - 0x30);
checkdigit = sum % 10;
if (checkdigit) /* not 0 */
checkdigit = 10 - checkdigit;
if (checkdigit + 0x30 != data[11])
L_WARNING("Error for EAN-13 check character\n", procName);
return data;
}