Added, at least, parsing of ECI mode in QR Code

[zxing.git] / core / src / com / google / zxing / qrcode / decoder / DecodedBitStreamParser.java

diff --git a/core/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java b/core/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java
index b53a7cf..b6dda58 100644 (file)
--- a/core/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java
+++ b/core/src/com/google/zxing/qrcode/decoder/DecodedBitStreamParser.java
@@ -60,20 +60,34 @@ final class DecodedBitStreamParser {
     Mode mode;
     do {
       // While still another segment to read...
-      mode = Mode.forBits(bits.readBits(4)); // mode is encoded by 4 bits
+      if (bits.available() == 0) {
+        // OK, assume we're done. Really, a TERMINATOR mode should have been recorded here
+        mode = Mode.TERMINATOR;
+      } else {
+        mode = Mode.forBits(bits.readBits(4)); // mode is encoded by 4 bits
+      }
       if (!mode.equals(Mode.TERMINATOR)) {
-        // How many characters will follow, encoded in this mode?
-        int count = bits.readBits(mode.getCharacterCountBits(version));
-        if (mode.equals(Mode.NUMERIC)) {
-          decodeNumericSegment(bits, result, count);
-        } else if (mode.equals(Mode.ALPHANUMERIC)) {
-          decodeAlphanumericSegment(bits, result, count);
-        } else if (mode.equals(Mode.BYTE)) {
-          decodeByteSegment(bits, result, count);
-        } else if (mode.equals(Mode.KANJI)) {
-          decodeKanjiSegment(bits, result, count);
+        if (mode.equals(Mode.ECI)) {
+          // Count doesn't apply to ECI
+          parseECI(bits);
+          // We don't currently do anything with ECI, since there seems to be no reference
+          // defining what each value means. AIM's "Extended Channel Interpretations" does
+          // not define it. I have never observed a QR Code using it. So for now, we at least
+          // parse it but don't know how to take action on it.
         } else {
-          throw new ReaderException("Unsupported mode indicator");
+          // How many characters will follow, encoded in this mode?
+         int count = bits.readBits(mode.getCharacterCountBits(version));
+          if (mode.equals(Mode.NUMERIC)) {
+            decodeNumericSegment(bits, result, count);
+          } else if (mode.equals(Mode.ALPHANUMERIC)) {
+            decodeAlphanumericSegment(bits, result, count);
+          } else if (mode.equals(Mode.BYTE)) {
+            decodeByteSegment(bits, result, count);
+          } else if (mode.equals(Mode.KANJI)) {
+            decodeKanjiSegment(bits, result, count);
+          } else {
+            throw new ReaderException("Unsupported mode indicator");
+          }
         }
       }
     } while (!mode.equals(Mode.TERMINATOR));
@@ -90,6 +104,23 @@ 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 secondByte = bits.readBits(8);
+      int thirdByte = bits.readBits(8);
+      return ((firstByte & 0x1F) << 16) | (secondByte << 8) | thirdByte;
+    }
+  }
+
   private static void decodeKanjiSegment(BitSource bits,
                                          StringBuffer result,
                                          int count) throws ReaderException {