externalize zxing lib, fix gradle build

1 files changed, 75 insertions, 0 deletions

diff --git a/libraries/zxing/src/com/google/zxing/common/reedsolomon/ReedSolomonEncoder.java b/libraries/zxing/src/com/google/zxing/common/reedsolomon/ReedSolomonEncoder.java
new file mode 100644
index 000000000..05e2ae03a
--- /dev/null
+++ b/libraries/zxing/src/com/google/zxing/common/reedsolomon/ReedSolomonEncoder.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2008 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.common.reedsolomon;
+
+import java.util.Vector;
+
+/**
+ * <p>Implements Reed-Solomon enbcoding, as the name implies.</p>
+ *
+ * @author Sean Owen
+ * @author William Rucklidge
+ */
+public final class ReedSolomonEncoder {
+
+  private final GenericGF field;
+  private final Vector cachedGenerators;
+
+  public ReedSolomonEncoder(GenericGF field) {
+    if (!GenericGF.QR_CODE_FIELD_256.equals(field)) {
+      throw new IllegalArgumentException("Only QR Code is supported at this time");
+    }
+    this.field = field;
+    this.cachedGenerators = new Vector();
+    cachedGenerators.addElement(new GenericGFPoly(field, new int[] { 1 }));
+  }
+
+  private GenericGFPoly buildGenerator(int degree) {
+    if (degree >= cachedGenerators.size()) {
+      GenericGFPoly lastGenerator = (GenericGFPoly) cachedGenerators.elementAt(cachedGenerators.size() - 1);
+      for (int d = cachedGenerators.size(); d <= degree; d++) {
+        GenericGFPoly nextGenerator = lastGenerator.multiply(new GenericGFPoly(field, new int[] { 1, field.exp(d - 1) }));
+        cachedGenerators.addElement(nextGenerator);
+        lastGenerator = nextGenerator;
+      }
+    }
+    return (GenericGFPoly) cachedGenerators.elementAt(degree);    
+  }
+
+  public void encode(int[] toEncode, int ecBytes) {
+    if (ecBytes == 0) {
+      throw new IllegalArgumentException("No error correction bytes");
+    }
+    int dataBytes = toEncode.length - ecBytes;
+    if (dataBytes <= 0) {
+      throw new IllegalArgumentException("No data bytes provided");
+    }
+    GenericGFPoly generator = buildGenerator(ecBytes);
+    int[] infoCoefficients = new int[dataBytes];
+    System.arraycopy(toEncode, 0, infoCoefficients, 0, dataBytes);
+    GenericGFPoly info = new GenericGFPoly(field, infoCoefficients);
+    info = info.multiplyByMonomial(ecBytes, 1);
+    GenericGFPoly remainder = info.divide(generator)[1];
+    int[] coefficients = remainder.getCoefficients();
+    int numZeroCoefficients = ecBytes - coefficients.length;
+    for (int i = 0; i < numZeroCoefficients; i++) {
+      toEncode[dataBytes + i] = 0;
+    }
+    System.arraycopy(coefficients, 0, toEncode, dataBytes + numZeroCoefficients, coefficients.length);
+  }
+
+}