Merge pull request #4 from ftiercelin/ISS1761

Refactor PDF417HighLevelEncoder to avoid code duplication

core/src/main/java/com/google/zxing/pdf417/encoder/PDF417HighLevelEncoder.java

@@ -176,24 +176,13 @@ final class PDF417HighLevelEncoder {
     }
     
     if (Compaction.TEXT == compaction) {
-      for (int i = 0; i < msg.length(); i++) {
+      checkCharset(msg,255,"Consider specifying Compaction.AUTO instead of Compaction.TEXT");
-        if (msg.charAt(i) > 255) {
-          throw new WriterException("Non-encodable character detected: " + msg.charAt(i) + " (Unicode: " +
-            (int) msg.charAt(i) +
-            "). Consider specifying Compaction.AUTO instead of Compaction.TEXT");
-        }
-      }
     }
 
     if (encoding == null && !autoECI) {
-      for (int i = 0; i < msg.length(); i++) {
+      checkCharset(msg,255,"Consider specifying EncodeHintType.PDF417_AUTO_ECI and/or EncodeTypeHint.CHARACTER_SET.");
-        if (msg.charAt(i) > 255) {
-          throw new WriterException("Non-encodable character detected: " + msg.charAt(i) + " (Unicode: " +
-              (int) msg.charAt(i) +
-              "). Consider specifying EncodeHintType.PDF417_AUTO_ECI and/or EncodeTypeHint.CHARACTER_SET.");
-        }
-      }
     }
+
     //the codewords 0..928 are encoded as Unicode characters
     StringBuilder sb = new StringBuilder(msg.length());
 
@@ -293,6 +282,22 @@ final class PDF417HighLevelEncoder {
 
     return sb.toString();
   }
+  
+  /**
+   * Check if input is only made of characters between 0 and the upper limit 
+   * @param input          the input
+   * @param max            the upper limit for charset
+   * @param errorMessage   the message to explain the error
+   * @throws WriterException exception highlighting the offending character and a suggestion to avoid the error
+   */
+  protected static void checkCharset(String input,int max, String errorMessage) throws WriterException {
+    for (int i = 0; i < input.length(); i++) {
+      if (input.charAt(i) > max) {
+        throw new WriterException("Non-encodable character detected: " + input.charAt(i) + " (Unicode: " +
+                (int) input.charAt(i) + "). " + errorMessage);
+      }
+    } 
+  }
 
   /**
    * Encode parts of the message using Text Compaction as described in ISO/IEC 15438:2001(E),

core/src/test/java/com/google/zxing/pdf417/encoder/PDF417EncoderTestCase.java

@@ -18,6 +18,7 @@ package com.google.zxing.pdf417.encoder;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.UUID;
 
 import com.google.zxing.BarcodeFormat;
 import com.google.zxing.EncodeHintType;
@@ -78,6 +79,26 @@ public final class PDF417EncoderTestCase extends Assert {
       assertTrue(e.getMessage().contains("Compaction.AUTO"));
     }
   }
+
+  @Test
+  public void testCheckCharset() throws Exception {
+    String input = "Hello!";
+    String errorMessage = UUID.randomUUID().toString();
+    
+    // no exception
+    PDF417HighLevelEncoder.checkCharset(input,255,errorMessage);
+    PDF417HighLevelEncoder.checkCharset(input,1255,errorMessage);
+    PDF417HighLevelEncoder.checkCharset(input,111,errorMessage);
+    
+    try {
+      // should throw an exception for character 'o' because it exceeds upper limit 110
+      PDF417HighLevelEncoder.checkCharset(input,110,errorMessage);
+    } catch (WriterException e) {
+      assertNotNull(e.getMessage());
+      assertTrue(e.getMessage().contains("111"));
+      assertTrue(e.getMessage().contains(errorMessage));
+    }
+  }
   
   @Test
   public void testEncodeIso88591WithSpecialChars() throws Exception {