[#257] Fixed failures on decoding ASCII text memos

src/main/java/org/stellar/sdk/Memo.java

@@ -2,6 +2,8 @@
 
 import com.google.common.io.BaseEncoding;
 
+import java.nio.charset.Charset;
+
 /**
  * <p>The memo contains optional extra information. It is the responsibility of the client to interpret this value. Memos can be one of the following types:</p>
  * <ul>
@@ -24,10 +26,18 @@ public static MemoNone none() {
 
     /**
      * Creates new {@link MemoText} instance.
-     * @param text
+     * @param text text in utf8 encoding
      */
     public static MemoText text(String text) {
-        return new MemoText(text);
+        return new MemoText(text, Charset.forName("UTF8"));
+    }
+
+    /**
+     * Creates new {@link MemoText} instance.
+     * @param text text in unknown encoding
+     */
+    public static MemoText textUnknownEncoding(String text) {
+        return new MemoText(text,null);
     }
 
     /**

src/main/java/org/stellar/sdk/MemoText.java

@@ -3,6 +3,7 @@
 import com.google.common.base.Objects;
 import org.stellar.sdk.xdr.MemoType;
 
+import javax.annotation.Nullable;
 import java.nio.charset.Charset;
 
 import static com.google.common.base.Preconditions.checkNotNull;
@@ -13,12 +14,19 @@
 public class MemoText extends Memo {
   private String text;
 
-  public MemoText(String text) {
+  public MemoText(String text, @Nullable Charset encoding) {
     this.text = checkNotNull(text, "text cannot be null");
 
-    int length = text.getBytes((Charset.forName("UTF-8"))).length;
+    int length;
+    if (encoding != null) {
+      length = text.getBytes(encoding).length;
+    } else {
+      int lengthUtf8 = text.getBytes((Charset.forName("UTF-8"))).length;
+      int lengthAscii = text.getBytes((Charset.forName("ASCII"))).length;
+      length = Math.min(lengthUtf8, lengthAscii);
+    }
     if (length > 28) {
-      throw new MemoTooLongException("text must be <= 28 bytes. length=" + String.valueOf(length));
+      throw new MemoTooLongException("text must be <= 28 bytes. length=" + length);
     }
   }
 

src/main/java/org/stellar/sdk/responses/TransactionDeserializer.java

@@ -33,7 +33,7 @@ public TransactionResponse deserialize(JsonElement json, Type typeOfT, JsonDeser
       if (memoType.equals("text")) {
         JsonElement memoField = json.getAsJsonObject().get("memo");
         if (memoField != null) {
-          memo = Memo.text(memoField.getAsString());
+          memo = Memo.textUnknownEncoding(memoField.getAsString());
         } else {
           memo = Memo.text("");
         }

src/test/java/org/stellar/sdk/MemoTest.java

@@ -9,6 +9,7 @@
 import org.stellar.sdk.responses.TransactionDeserializer;
 import org.stellar.sdk.responses.TransactionResponse;
 
+import java.nio.charset.Charset;
 import java.util.Arrays;
 
 import static org.junit.Assert.*;
@@ -50,7 +51,7 @@ public void testMemoTextTooLong() {
     @Test
     public void testMemoTextTooLongUtf8() {
         try {
-            Memo.text("价值交易的开源协议!!");
+            new MemoText("价值交易的开源协议!!", Charset.forName("UTF8"));
             fail();
         } catch (RuntimeException exception) {
             assertTrue(exception.getMessage().contains("text must be <= 28 bytes."));
@@ -136,4 +137,29 @@ public void testMemoReturnHashSuccess() {
         assertEquals("4142434445464748494a4b4c0000000000000000000000000000000000000000", BaseEncoding.base16().lowerCase().encode(memoXdr.getRetHash().getHash()));
         assertEquals("4142434445464748494a4b4c", memo.getTrimmedHexValue());
     }
+
+    @Test
+    public void testMemoTextAscii() {
+        String asciiStr = "\u0223\u0025\ufffd\u0060\ufffd\ufffd\ufffd\u006d\u005a\u0041\u0076\u000e\ufffd\ufffd\u0002\u0049\u0004\ufffd\ufffd\ufffd\ufffd\ufffd\u0062\ufffd\u0031\ufffd\u0010";
+        try {
+            Memo.text(asciiStr);
+            fail(); // More then 28 bytes in UTF8 encoding
+        } catch (MemoTooLongException e) {
+        }
+        MemoText memo = Memo.textUnknownEncoding(asciiStr);
+        assertEquals(asciiStr, memo.getText());
+        assertEquals(asciiStr, memo.toString());
+    }
+
+    @Test
+    public void testMemoTextAsciiTooLong() {
+        String longStr = "\u0223\u0025\ufffd\u0060\ufffd\ufffd\ufffd\u006d\u005a\u0041\u0076\u000e\ufffd\ufffd\u0002\u0049\u0004\ufffd\ufffd\ufffd\ufffd\ufffd\u0062\ufffd\u0031\ufffd\u0010\u0028\u0029";
+
+        try {
+            Memo.textUnknownEncoding(longStr);
+            fail();
+        } catch (MemoTooLongException exception) {
+            assertTrue(exception.getMessage().contains("text must be <= 28 bytes."));
+        }
+    }
 }