Ported r2387 from ZXing

Original commit message: "Issue 1332 fix EDIFACT decoding"

ZXingObjC/common/ZXBitSource.h

@@ -24,6 +24,7 @@
 
 @interface ZXBitSource : NSObject
 
+@property (nonatomic, assign, readonly) int bitOffset;
 @property (nonatomic, assign, readonly) int byteOffset;
 
 - (id)initWithBytes:(unsigned char *)bytes length:(unsigned int)length;

ZXingObjC/datamatrix/decoder/ZXDataMatrixDecodedBitStreamParser.m

@@ -435,7 +435,6 @@ + (void)parseTwoBytes:(int)firstByte secondByte:(int)secondByte result:(int[])re
  * See ISO 16022:2006, 5.2.8 and Annex C Table C.3
  */
 + (void)decodeEdifactSegment:(ZXBitSource *)bits result:(NSMutableString *)result {
-  BOOL unlatch = NO;
   do {
     // If there is only two or less bytes left then it will be encoded as ASCII
     if (bits.available <= 16) {
@@ -447,19 +446,20 @@ + (void)decodeEdifactSegment:(ZXBitSource *)bits result:(NSMutableString *)resul
 
       // Check for the unlatch character
       if (edifactValue == 0x1F) {  // 011111
-        unlatch = YES;
-        // If we encounter the unlatch code then continue reading because the Codeword triple
-        // is padded with 0's
+        // Read rest of byte, which should be 0, and stop
+        int bitsLeft = 8 - bits.bitOffset;
+        if (bitsLeft != 8) {
+          [bits readBits:bitsLeft];
+        }
+        return;
       }
 
-      if (!unlatch) {
-        if ((edifactValue & 0x20) == 0) {  // no 1 in the leading (6th) bit
-          edifactValue |= 0x40;  // Add a leading 01 to the 6 bit binary value
-        }
-        [result appendFormat:@"%c", (char)edifactValue];
+      if ((edifactValue & 0x20) == 0) {  // no 1 in the leading (6th) bit
+        edifactValue |= 0x40;  // Add a leading 01 to the 6 bit binary value
       }
+      [result appendFormat:@"%c", (char)edifactValue];
     }
-  } while (!unlatch && bits.available > 0);
+  } while (bits.available > 0);
 }