Added some degree of support for Character Set ECIs

git-svn-id: https://zxing.googlecode.com/svn/trunk@467 59b500cc-1b3d-0410-9834-0bbf25fbcc57

core/src/com/google/zxing/qrcode/decoder/CharacterSetECI.java

@@ -0,0 +1,73 @@
+/*
+ * 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.qrcode.decoder;
+
+import java.util.Hashtable;
+
+/**
+ * Encapsulates a Character Set ECI, according to "Extended Channel Interpretations" 5.3.1.1.
+ *
+ * @author srowen@google.com (Sean Owen)
+ */
+final class CharacterSetECI extends ECI {
+
+  private static final Hashtable VALUE_TO_ECI;
+  static {
+    VALUE_TO_ECI = new Hashtable(29);
+    // TODO figure out if these values are even right!
+    addCharacterSet(3, "ISO8859_1");
+    addCharacterSet(4, "ISO8859_2");
+    addCharacterSet(5, "ISO8859_3");
+    addCharacterSet(6, "ISO8859_4");
+    addCharacterSet(7, "ISO8859_5");
+    addCharacterSet(8, "ISO8859_6");
+    addCharacterSet(9, "ISO8859_7");
+    addCharacterSet(10, "ISO8859_8");
+    addCharacterSet(11, "ISO8859_9");
+    addCharacterSet(12, "ISO8859_10");
+    addCharacterSet(13, "ISO8859_11");
+    addCharacterSet(15, "ISO8859_13");
+    addCharacterSet(16, "ISO8859_14");
+    addCharacterSet(17, "ISO8859_15");
+    addCharacterSet(18, "ISO8859_16");
+    addCharacterSet(20, "Shift_JIS");
+  }
+
+  private final String encodingName;
+
+  private CharacterSetECI(int value, String encodingName) {
+    super(value);
+    this.encodingName = encodingName;
+  }
+
+  String getEncodingName() {
+    return encodingName;
+  }
+
+  private static void addCharacterSet(int value, String encodingName) {
+    VALUE_TO_ECI.put(new Integer(value), new CharacterSetECI(value, encodingName));
+  }
+
+  static CharacterSetECI getCharacterSetECIByValue(int value) {
+    CharacterSetECI eci = (CharacterSetECI) VALUE_TO_ECI.get(new Integer(value));
+    if (eci == null) {
+      throw new IllegalArgumentException("Unsupported value: " + value);
+    }
+    return eci;
+  }
+
+}

core/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java

@@ -57,6 +57,7 @@ final class DecodedBitStreamParser {
   static String decode(byte[] bytes, Version version) throws ReaderException {
     BitSource bits = new BitSource(bytes);
     StringBuffer result = new StringBuffer();
+    CharacterSetECI currentCharacterSetECI = null;
     Mode mode;
     do {
       // While still another segment to read...
@@ -69,11 +70,12 @@ final class DecodedBitStreamParser {
       if (!mode.equals(Mode.TERMINATOR)) {
         if (mode.equals(Mode.ECI)) {
           // Count doesn't apply to ECI
-          parseECI(bits);
+          int value = ECI.parseECI(bits);
-          // We don't currently do anything with ECI, since there seems to be no reference
+          try {
-          // defining what each value means. AIM's "Extended Channel Interpretations" does
+            currentCharacterSetECI = CharacterSetECI.getCharacterSetECIByValue(value);
-          // not define it. I have never observed a QR Code using it. So for now, we at least
+          } catch (IllegalArgumentException iae) {
-          // parse it but don't know how to take action on it.
+            // unsupported... just continue?
+          }
         } else {
           // How many characters will follow, encoded in this mode?
          int count = bits.readBits(mode.getCharacterCountBits(version));
@@ -82,7 +84,7 @@ final class DecodedBitStreamParser {
           } else if (mode.equals(Mode.ALPHANUMERIC)) {
             decodeAlphanumericSegment(bits, result, count);
           } else if (mode.equals(Mode.BYTE)) {
-            decodeByteSegment(bits, result, count);
+            decodeByteSegment(bits, result, count, currentCharacterSetECI);
           } else if (mode.equals(Mode.KANJI)) {
             decodeKanjiSegment(bits, result, count);
           } else {
@@ -104,23 +106,6 @@ final class DecodedBitStreamParser {
     return result.toString();
   }
 
-  private static int parseECI(BitSource bits) {
-    int firstByte = bits.readBits(8);
-    if ((firstByte & 0x80) == 0) {
-      // just one byte
-      return firstByte & 0x7F;
-    } else if ((firstByte & 0xC0) == 0x80) {
-      // two bytes
-      int secondByte = bits.readBits(8);
-      return ((firstByte & 0x3F) << 8) | secondByte;
-    } else if ((firstByte & 0xE0) == 0xC0) {
-      // three bytes
-      int secondThirdBytes = bits.readBits(16);
-      return ((firstByte & 0x1F) << 16) | secondThirdBytes;
-    }
-    throw new IllegalArgumentException("Bad ECI bits starting with byte " + firstByte);
-  }
-
   private static void decodeKanjiSegment(BitSource bits,
                                          StringBuffer result,
                                          int count) throws ReaderException {
@@ -154,7 +139,8 @@ final class DecodedBitStreamParser {
 
   private static void decodeByteSegment(BitSource bits,
                                         StringBuffer result,
-                                        int count) throws ReaderException {
+                                        int count,
+                                        CharacterSetECI currentCharacterSetECI) throws ReaderException {
     byte[] readBytes = new byte[count];
     if (count << 3 > bits.available()) {
       throw new ReaderException("Count too large: " + count);
@@ -162,12 +148,17 @@ final class DecodedBitStreamParser {
     for (int i = 0; i < count; i++) {
       readBytes[i] = (byte) bits.readBits(8);
     }
+    String encoding;
+    if (currentCharacterSetECI == null) {
     // The spec isn't clear on this mode; see
     // section 6.4.5: t does not say which encoding to assuming
     // upon decoding. I have seen ISO-8859-1 used as well as
     // Shift_JIS -- without anything like an ECI designator to
     // give a hint.
-    String encoding = guessEncoding(readBytes);
+      encoding = guessEncoding(readBytes);
+    } else {
+      encoding = currentCharacterSetECI.getEncodingName();
+    }
     try {
       result.append(new String(readBytes, encoding));
     } catch (UnsupportedEncodingException uce) {

core/src/com/google/zxing/qrcode/decoder/ECI.java

@@ -0,0 +1,65 @@
+/*
+ * 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.qrcode.decoder;
+
+import com.google.zxing.common.BitSource;
+
+/**
+ * Superclass of classes encapsulating types ECIs, according to "Extended Channel Interpretations" 5.3.
+ *
+ * @author srowen@google.com (Sean Owen)
+ */
+abstract class ECI {
+
+  private final int value;
+
+  ECI(int value) {
+    this.value = value;
+  }
+
+  int getValue() {
+    return value;
+  }
+
+  static ECI getECIByValue(int value) {
+    if (value < 0 || value > 999999) {
+      throw new IllegalArgumentException("Bad ECI value: " + value);
+    }
+    if (value < 900) { // Character set ECIs use 000000 - 000899
+      return CharacterSetECI.getCharacterSetECIByValue(value);
+    }
+    throw new IllegalArgumentException("Unsupported ECI value: " + value);
+  }
+
+  static int parseECI(BitSource bits) {
+    int firstByte = bits.readBits(8);
+    if ((firstByte & 0x80) == 0) {
+      // just one byte
+      return firstByte & 0x7F;
+    } else if ((firstByte & 0xC0) == 0x80) {
+      // two bytes
+      int secondByte = bits.readBits(8);
+      return ((firstByte & 0x3F) << 8) | secondByte;
+    } else if ((firstByte & 0xE0) == 0xC0) {
+      // three bytes
+      int secondThirdBytes = bits.readBits(16);
+      return ((firstByte & 0x1F) << 16) | secondThirdBytes;
+    }
+    throw new IllegalArgumentException("Bad ECI bits starting with byte " + firstByte);
+  }
+
+}

core/test/src/com/google/zxing/qrcode/decoder/ECITestCase.java

@@ -0,0 +1,42 @@
+/*
+ * 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.qrcode.decoder;
+
+import com.google.zxing.common.BitSource;
+import junit.framework.TestCase;
+
+/**
+ * @author srowen@google.com (Sean Owen)
+ */
+public final class ECITestCase extends TestCase {
+
+  public void testParseECI() {
+    doTestParseECI(0, new byte[] { (byte) 0x00 });
+    doTestParseECI(127, new byte[] { (byte) 0x7F });
+    doTestParseECI(128, new byte[] { (byte) 0x80, (byte) 0x80 });
+    doTestParseECI(16383, new byte[] { (byte) 0xBF, (byte) 0xFF });
+    doTestParseECI(16384, new byte[] { (byte) 0xC0, (byte) 0x40, (byte) 0x00 });
+    doTestParseECI(2097151, new byte[] { (byte) 0xDF, (byte) 0xFF, (byte) 0xFF });
+  }
+
+  private static void doTestParseECI(int expectedValue, byte[] bytes) {
+    BitSource bitSource = new BitSource(bytes);
+    int actual = ECI.parseECI(bitSource);
+    assertEquals(expectedValue, actual);
+  }
+
+}