Added a Code 93 encoder

AUTHORS

@@ -77,6 +77,7 @@ Luka Finžgar
 Malte Starostik
 Manuel Kasten
 Marcelo
+Marcin Górny
 Markus Helm
 Mateusz Jędrasik
 Matthew Schulkind (Google)

core/src/main/java/com/google/zxing/MultiFormatWriter.java

@@ -22,6 +22,7 @@ import com.google.zxing.datamatrix.DataMatrixWriter;
 import com.google.zxing.oned.CodaBarWriter;
 import com.google.zxing.oned.Code128Writer;
 import com.google.zxing.oned.Code39Writer;
+import com.google.zxing.oned.Code93Writer;
 import com.google.zxing.oned.EAN13Writer;
 import com.google.zxing.oned.EAN8Writer;
 import com.google.zxing.oned.ITFWriter;
@@ -74,6 +75,9 @@ public final class MultiFormatWriter implements Writer {
       case CODE_39:
         writer = new Code39Writer();
         break;
+      case CODE_93:
+        writer = new Code93Writer();
+        break;
       case CODE_128:
         writer = new Code128Writer();
         break;

core/src/main/java/com/google/zxing/oned/Code93Reader.java

@@ -37,14 +37,14 @@ import java.util.Map;
 public final class Code93Reader extends OneDReader {
 
   // Note that 'abcd' are dummy characters in place of control characters.
-  private static final String ALPHABET_STRING = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%abcd*";
+  static final String ALPHABET_STRING = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%abcd*";
   private static final char[] ALPHABET = ALPHABET_STRING.toCharArray();
 
   /**
    * These represent the encodings of characters, as patterns of wide and narrow bars.
    * The 9 least-significant bits of each int correspond to the pattern of wide and narrow.
    */
-  private static final int[] CHARACTER_ENCODINGS = {
+  static final int[] CHARACTER_ENCODINGS = {
       0x114, 0x148, 0x144, 0x142, 0x128, 0x124, 0x122, 0x150, 0x112, 0x10A, // 0-9
       0x1A8, 0x1A4, 0x1A2, 0x194, 0x192, 0x18A, 0x168, 0x164, 0x162, 0x134, // A-J
       0x11A, 0x158, 0x14C, 0x146, 0x12C, 0x116, 0x1B4, 0x1B2, 0x1AC, 0x1A6, // K-T

core/src/main/java/com/google/zxing/oned/Code93Writer.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2015 ZXing authors
+ *
+ * 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.oned;
+
+import com.google.zxing.BarcodeFormat;
+import com.google.zxing.EncodeHintType;
+import com.google.zxing.WriterException;
+import com.google.zxing.common.BitMatrix;
+
+import java.util.Map;
+
+/**
+ * This object renders a CODE93 code as a BitMatrix
+ */
+public class Code93Writer extends OneDimensionalCodeWriter {
+  @Override
+  public BitMatrix encode(String contents,
+                          BarcodeFormat format,
+                          int width,
+                          int height,
+                          Map<EncodeHintType,?> hints) throws WriterException {
+    if (format != BarcodeFormat.CODE_93) {
+      throw new IllegalArgumentException("Can only encode CODE_93, but got " + format);
+    }
+    return super.encode(contents, format, width, height, hints);
+  }
+
+  @Override
+  public boolean[] encode(String contents) {
+    int length = contents.length();
+    if (length > 80) {
+      throw new IllegalArgumentException(
+        "Requested contents should be less than 80 digits long, but got " + length);
+    }
+    //each character is encoded by 9 of 0/1's
+    int[] widths = new int[9];
+
+    //lenght of code + 2 start/stop characters + 2 checksums, each of 9 bits, plus a termination bar
+    int codeWidth = (contents.length() + 2 + 2) * 9 + 1;
+
+    boolean[] result = new boolean[codeWidth];
+
+    //start character (*)
+    toIntArray(Code93Reader.CHARACTER_ENCODINGS[47], widths);
+    int pos = appendPattern(result, 0, widths, true);
+
+    for (int i = 0; i < length; i++) {
+      int indexInString = Code93Reader.ALPHABET_STRING.indexOf(contents.charAt(i));
+      toIntArray(Code93Reader.CHARACTER_ENCODINGS[indexInString], widths);
+      pos += appendPattern(result, pos, widths, true);
+    }
+
+    //add two checksums
+    int check1 = computeChecksumIndex(contents, 20);
+    toIntArray(Code93Reader.CHARACTER_ENCODINGS[check1], widths);
+    pos += appendPattern(result, pos, widths, true);
+
+    //append the contents to reflect the first checksum added
+    contents += Code93Reader.ALPHABET_STRING.charAt(check1);
+
+    int check2 = computeChecksumIndex(contents, 15);
+    toIntArray(Code93Reader.CHARACTER_ENCODINGS[check2], widths);
+    pos += appendPattern(result, pos, widths, true);
+
+    //end character (*)
+    toIntArray(Code93Reader.CHARACTER_ENCODINGS[47], widths);
+    pos += appendPattern(result, pos, widths, true);
+
+    //termination bar (single black bar)
+    result[pos] = true;
+
+    return result;
+  }
+
+  private static void toIntArray(int a, int[] toReturn) {
+    for (int i = 0; i < 9; i++) {
+      int temp = a & (1 << (8 - i));
+      toReturn[i] = temp == 0 ? 0 : 1;
+    }
+  }
+
+  protected static int appendPattern(boolean[] target, int pos, int[] pattern, boolean startColor) {
+    for (int bit : pattern) {
+      target[pos++] = bit != 0;
+    }
+    return 9;
+  }
+
+  private static int computeChecksumIndex(String contents, int maxWeight) {
+    int weight = 1;
+    int total = 0;
+
+    for (int i = contents.length() - 1; i >= 0; i--) {
+      int indexInString = Code93Reader.ALPHABET_STRING.indexOf(contents.charAt(i));
+      total += indexInString * weight;
+      if (++weight > maxWeight) {
+        weight = 1;
+      }
+    }
+    return total % 47;
+  }
+}