mirrors/zint
2
0
Fork 0
mirror of https://github.com/zint/zint synced 2024-11-16 20:57:25 +13:00
Code Issues Actions Packages Projects Releases Wiki Activity

Ultracode: Add error correction

Browse Source
This commit is contained in:
Robin Stuart 2019-12-15 12:58:59 +00:00
parent 7216202f06
commit 77c8e76bfa
1 changed files with 165 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

177
backend/ultra.c
View File

@ -44,6 +44,8 @@
#define PREDICT_WINDOW 12
#define GFMUL(i, j) ((((i) == 0)||((j) == 0)) ? 0 : gfPwr[(gfLog[i] + gfLog[j])])
static const char fragment[27][14] = {"http://", "https://", "http://www.", "https://www.",
"ftp://", "www.", ".com", ".edu", ".gov", ".int", ".mil", ".net", ".org",
".mobi", ".coop", ".biz", ".info", "mailto:", "tel:", ".cgi", ".asp",
@ -54,6 +56,86 @@ static const char ultra_c43_set2[] = "abcdefghijklmnopqrstuvwxyz:/?#[]@=_~!.,-";
static const char ultra_c43_set3[] = "{}`()\"+'<>|$;&\\^*";
static const char ultra_digit[] = "0123456789,/";
/* The following adapted from ECC283.C "RSEC codeword generator"
* from Annex B of Ultracode draft
* originally written by Ted Williams of Symbol Vision Corp.
* Dated 2001-03-09
* Corrected thanks to input from Terry Burton */
/* Generate divisor polynomial gQ(x) for GF283() given the required ECC size, 3 to 101 */
void ultra_genPoly(short EccSize, unsigned short gPoly[], unsigned short gfPwr[], unsigned short gfLog[]) {
int i, j;
gPoly[0] = 1;
for (i = 1; i < (EccSize + 1); i++) gPoly[i] = 0;
for (i = 0; i < EccSize; i++) {
for (j = i; j >= 0; j--)
gPoly[j + 1] = (gPoly[j] + GFMUL(gPoly[j + 1], gfPwr[i + 1])) % 283;
gPoly[0] = GFMUL(gPoly[0], gfPwr[i + 1]);
}
for (i = EccSize - 1; i >= 0; i -= 2) gPoly[i] = 283 - gPoly[i];
/* gPoly[i] is > 0 so modulo operation not needed */
}
/* Generate the log and antilog tables for GF283() multiplication & division */
void ultra_initLogTables(unsigned short gfPwr[], unsigned short gfLog[]) {
int i, j;
for (j = 0; j < 283; j++) gfLog[j] = 0;
i = 1;
for (j = 0; j < 282; j++) {
/* j + 282 indicies save doing the modulo operation in GFMUL */
gfPwr[j + 282] = gfPwr[j] = (short) i;
gfLog[i] = (short) j;
i = (i * 3) % 283;
}
}
void ultra_gf283(short DataSize, short EccSize, int Message[]) {
/* Input is complete message codewords in array Message[282]
* DataSize is number of message codewords
* EccSize is number of Reed-Solomon GF(283) check codewords to generate
*
* Upon exit, Message[282] contains complete 282 codeword Symbol Message
* including leading zeroes corresponding to each truncated codeword */
unsigned short gPoly[283], gfPwr[(282 * 2)], gfLog[283];
int i, j, n;
unsigned short t;
/* first build the log & antilog tables used in multiplication & division */
ultra_initLogTables(gfPwr, gfLog);
/* then generate the division polynomial of length EccSize */
ultra_genPoly(EccSize, gPoly, gfPwr, gfLog);
/* zero all EccSize codeword values */
for (j = 281; (j > (281 - EccSize)); j--) Message[j] = 0;
/* shift message codewords to the right, leave space for ECC checkwords */
for (i = DataSize - 1; (i >= 0); j--, i--) Message[j] = Message[i];
/* add zeroes to pad left end Message[] for truncated codewords */
j++;
for (i = 0; i < j; i++) Message[i] = 0;
/* generate (EccSize) Reed-Solomon checkwords */
for (n = j; n < (j + DataSize); n++) {
t = (Message[j + DataSize] + Message[n]) % 283;
for (i = 0; i < (EccSize - 1); i++) {
Message[j + DataSize + i] = (Message[j + DataSize + i + 1] + 283
- GFMUL(t, gPoly[EccSize - 1 - i])) % 283;
}
Message[j + DataSize + EccSize - 1] = (283 - GFMUL(t, gPoly[0])) % 283;
}
for (i = j + DataSize; i < (j + DataSize + EccSize); i++)
Message[i] = (283 - Message[i]) % 283;
}
/* End of Ted Williams code */
int ultra_find_fragment(unsigned char source[], int source_length, int position) {
int retval = -1;
int j, k, latch;
@ -543,8 +625,8 @@ int ultra_generate_codewords(struct zint_symbol *symbol, const unsigned char sou
}
codeword_count++;
for (i = input_posn + 7; i < (in_length - 2); i++) {
crop_source[i - input_posn] = source[i];
for (i = 7; i < (in_length - 2); i++) {
crop_source[i - 7] = source[i];
}
crop_length = in_length - 9;
crop_source[crop_length] = '\0';
@ -639,24 +721,36 @@ int ultra_generate_codewords(struct zint_symbol *symbol, const unsigned char sou
int ultracode(struct zint_symbol *symbol, const unsigned char source[], const size_t in_length) {
int data_cw_count = 0;
int ecc_cw;
int ecc_level; // = Q in section 7.7.1
int ecc_cw; // = Q in section 7.7.1
int ecc_level;
int misdecode_cw; // = P in section 7.7.1
int rows, columns;
int total_cws;
int pads;
int cw_memalloc;
int codeword[283];
int i, posn;
int acc;
cw_memalloc = in_length * 2;
if (cw_memalloc < 283) {
cw_memalloc = 283;
}
#ifndef _MSC_VER
int data_codewords[in_length * 2];
int data_codewords[cw_memalloc];
#else
int* data_codewords = (int *) _alloca(in_length * 2 * sizeof (int));
int* data_codewords = (int *) _alloca(cw_memalloc * sizeof (int));
#endif /* _MSC_VER */
data_cw_count = ultra_generate_codewords(symbol, source, in_length, data_codewords);
printf("Codewords returned = %d\n", data_cw_count);
//printf("Codewords returned = %d\n", data_cw_count);
for (int i = 0; i < data_cw_count; i++) {
printf("%d ", data_codewords[i]);
}
printf("\n");
//for (int i = 0; i < data_cw_count; i++) {
// printf("%d ", data_codewords[i]);
//}
//printf("\n");
/* Default ECC level is EC2 */
if ((symbol->option_1 <= 0) || (symbol->option_1 > 6)) {
@ -678,7 +772,7 @@ int ultracode(struct zint_symbol *symbol, const unsigned char source[], const si
ecc_cw = (ecc_level * ((data_cw_count / 25) + 1)) + misdecode_cw + 2;
}
printf("ECC codewords: %d\n", ecc_cw);
//printf("ECC codewords: %d\n", ecc_cw);
/* Maximum capacity is 282 codewords */
if (data_cw_count + ecc_cw > 282) {
@ -686,6 +780,65 @@ int ultracode(struct zint_symbol *symbol, const unsigned char source[], const si
return ZINT_ERROR_TOO_LONG;
}
total_cws = data_cw_count + ecc_cw;
rows = 5;
if (total_cws < 164) {
rows = 4;
}
if (total_cws < 84) {
rows = 3;
}
if (total_cws < 40) {
rows = 2;
}
if ((total_cws % rows) == 0) {
pads = 0;
columns = total_cws / rows;
} else {
pads = rows - (total_cws % rows);
columns = (total_cws + pads) / rows;
}
printf("Calculated size is %d rows by %d columns\n", rows, columns);
acc = ecc_cw - misdecode_cw; // ACC = (Q-P) - section 6.11.6
/* Insert MCC and ACC into data codewords */
for (i = 282; i > 2; i--) {
data_codewords[i] = data_codewords[i - 2];
}
data_codewords[1] = data_cw_count += 2; // MCC
data_codewords[2] = acc; // ACC
/* Calculate error correction codewords (RSEC) */
ultra_gf283((short) data_cw_count, (short) ecc_cw, data_codewords);
/* Rearrange to make final codeword sequence */
posn = 0;
codeword[posn++] = data_codewords[282 - (data_cw_count + ecc_cw)]; // Start Character
codeword[posn++] = data_cw_count; // MCC
for (i = 0; i < ecc_cw; i++) {
codeword[posn++] = data_codewords[(282 - ecc_cw) + i]; // RSEC Region
}
codeword[posn++] = data_cw_count + ecc_cw; // TCC = C + Q - section 6.11.4
codeword[posn++] = 283; // Separator
codeword[posn++] = acc; // ACC
for (i = 0; i < (data_cw_count - 3); i++) {
codeword[posn++] = data_codewords[(282 - ((data_cw_count - 3) + ecc_cw)) + i]; // Data Region
}
for (i = 0; i < pads; i++) {
codeword[posn++] = 284; // Pad pattern
}
codeword[posn++] = ecc_cw; // QCC
printf("Rearranged codewords with ECC:\n");
for (i = 0; i < posn; i++) {
printf("%d ", codeword[i]);
}
printf("\n");
strcpy(symbol->errtxt, "1000: Ultracode has not been implemented - yet!");
return ZINT_ERROR_INVALID_OPTION;
}