/*
* Copyright 2006 Jeremias Maerki.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing.datamatrix.encoder;
import java.util.Arrays;
/**
* Symbol Character Placement Program. Adapted from Annex M.1 in ISO/IEC
* 16022:2000(E).
*/
public class DefaultPlacement {
private final CharSequence codewords;
private final int numrows;
private final int numcols;
private final byte[] bits;
/**
* Main constructor
*
* @param codewords
* the codewords to place
* @param numcols
* the number of columns
* @param numrows
* the number of rows
*/
public DefaultPlacement(CharSequence codewords, int numcols, int numrows) {
this.codewords = codewords;
this.numcols = numcols;
this.numrows = numrows;
this.bits = new byte[numcols * numrows];
Arrays.fill(this.bits, (byte) -1); // Initialize with "not set" value
}
final int getNumrows() {
return numrows;
}
final int getNumcols() {
return numcols;
}
final byte[] getBits() {
return bits;
}
public final boolean getBit(int col, int row) {
return bits[row * numcols + col] == 1;
}
final void setBit(int col, int row, boolean bit) {
bits[row * numcols + col] = bit ? (byte) 1 : (byte) 0;
}
final boolean hasBit(int col, int row) {
return bits[row * numcols + col] >= 0;
}
public final void place() {
int pos = 0;
int row = 4;
int col = 0;
do {
/*
* repeatedly first check for one of the special corner cases,
* then...
*/
if ((row == numrows) && (col == 0)) {
corner1(pos++);
}
if ((row == numrows - 2) && (col == 0) && ((numcols % 4) != 0)) {
corner2(pos++);
}
if ((row == numrows - 2) && (col == 0) && (numcols % 8 == 4)) {
corner3(pos++);
}
if ((row == numrows + 4) && (col == 2) && ((numcols % 8) == 0)) {
corner4(pos++);
}
/* sweep upward diagonally, inserting successive characters... */
do {
if ((row < numrows) && (col >= 0) && !hasBit(col, row)) {
utah(row, col, pos++);
}
row -= 2;
col += 2;
} while (row >= 0 && (col < numcols));
row++;
col += 3;
/*
* and then sweep downward diagonally, inserting successive
* characters, ...
*/
do {
if ((row >= 0) && (col < numcols) && !hasBit(col, row)) {
utah(row, col, pos++);
}
row += 2;
col -= 2;
} while ((row < numrows) && (col >= 0));
row += 3;
col++;
/* ...until the entire array is scanned */
} while ((row < numrows) || (col < numcols));
/*
* Lastly, if the lower righthand corner is untouched, fill in fixed
* pattern
*/
if (!hasBit(numcols - 1, numrows - 1)) {
setBit(numcols - 1, numrows - 1, true);
setBit(numcols - 2, numrows - 2, true);
}
}
private void module(int row, int col, int pos, int bit) {
if (row < 0) {
row += numrows;
col += 4 - ((numrows + 4) % 8);
}
if (col < 0) {
col += numcols;
row += 4 - ((numcols + 4) % 8);
}
// Note the conversion:
int v = codewords.charAt(pos);
v &= 1 << (8 - bit);
setBit(col, row, v != 0);
}
/**
* Places the 8 bits of a utah-shaped symbol character in ECC200.
*
* @param row
* the row
* @param col
* the column
* @param pos
* character position
*/
private void utah(int row, int col, int pos) {
module(row - 2, col - 2, pos, 1);
module(row - 2, col - 1, pos, 2);
module(row - 1, col - 2, pos, 3);
module(row - 1, col - 1, pos, 4);
module(row - 1, col, pos, 5);
module(row, col - 2, pos, 6);
module(row, col - 1, pos, 7);
module(row, col, pos, 8);
}
private void corner1(int pos) {
module(numrows - 1, 0, pos, 1);
module(numrows - 1, 1, pos, 2);
module(numrows - 1, 2, pos, 3);
module(0, numcols - 2, pos, 4);
module(0, numcols - 1, pos, 5);
module(1, numcols - 1, pos, 6);
module(2, numcols - 1, pos, 7);
module(3, numcols - 1, pos, 8);
}
private void corner2(int pos) {
module(numrows - 3, 0, pos, 1);
module(numrows - 2, 0, pos, 2);
module(numrows - 1, 0, pos, 3);
module(0, numcols - 4, pos, 4);
module(0, numcols - 3, pos, 5);
module(0, numcols - 2, pos, 6);
module(0, numcols - 1, pos, 7);
module(1, numcols - 1, pos, 8);
}
private void corner3(int pos) {
module(numrows - 3, 0, pos, 1);
module(numrows - 2, 0, pos, 2);
module(numrows - 1, 0, pos, 3);
module(0, numcols - 2, pos, 4);
module(0, numcols - 1, pos, 5);
module(1, numcols - 1, pos, 6);
module(2, numcols - 1, pos, 7);
module(3, numcols - 1, pos, 8);
}
private void corner4(int pos) {
module(numrows - 1, 0, pos, 1);
module(numrows - 1, numcols - 1, pos, 2);
module(0, numcols - 3, pos, 3);
module(0, numcols - 2, pos, 4);
module(0, numcols - 1, pos, 5);
module(1, numcols - 3, pos, 6);
module(1, numcols - 2, pos, 7);
module(1, numcols - 1, pos, 8);
}
}