Fix #139

Author: cowtowncoder

cbor/src/main/java/com/fasterxml/jackson/dataformat/cbor/CBORGenerator.java

@@ -1032,11 +1032,11 @@ public void writeNumber(BigDecimal dec) throws IOException {
         _writeByte(BYTE_TAG_DECIMAL_FRACTION);
         _writeByte(BYTE_ARRAY_2_ELEMENTS);
 
+        // 27-Nov-2019, tatu: As per [dataformats-binary#139] need to change sign here
         int scale = dec.scale();
-        _writeIntValue(scale);
-        /* Hmmmh. Specification suggest use of regular integer for mantissa. But
-         * if it doesn't fit, use "bignum"
-         */
+        _writeIntValue(-scale);
+        // Hmmmh. Specification suggest use of regular integer for mantissa. But
+        // if it doesn't fit, use "bignum"
         BigInteger unscaled = dec.unscaledValue();
         int bitLength = unscaled.bitLength();
         if (bitLength <= 31) {

cbor/src/main/java/com/fasterxml/jackson/dataformat/cbor/CBORParser.java

@@ -882,7 +882,8 @@ protected JsonToken _handleTaggedArray(int tag, int len) throws IOException
         if (t != JsonToken.VALUE_NUMBER_INT) {
             _reportError("Unexpected token ("+t+") as the first part of 'bigfloat' value: should get VALUE_NUMBER_INT");
         }
-        int exp = getIntValue();
+        // 27-Nov-2019, tatu: As per [dataformats-binary#139] need to change sign here
+        int exp = -getIntValue();
 
         t = nextToken();
         // Should get an integer value; int/long/BigInteger

cbor/src/test/java/com/fasterxml/jackson/dataformat/cbor/GeneratorSimpleTest.java

@@ -197,6 +197,27 @@ public void testFloatValues() throws Exception
                 (byte) rawL);
     }
 
+    // [dataformats-binary#139]: wrong encoding of BigDecimal
+    public void testBigDecimalValues() throws Exception
+    {
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        CBORGenerator gen = cborGenerator(out);
+        final BigDecimal NR = new BigDecimal("273.15");
+        gen.writeNumber(NR);
+        gen.close();
+        byte[] b = out.toByteArray();
+
+        // [https://tools.ietf.org/html/rfc7049#section-2.4.2]
+        final byte[] spec = new byte[] {
+                (byte) 0xC4,  // tag 4
+                (byte) 0x82,  // Array of length 2
+                0x21,  // int -- -2
+                0x19, 0x6a, (byte) 0xb3 // int 27315
+        };
+        assertEquals(spec.length, b.length);
+        Assert.assertArrayEquals(spec, b);
+    }
+    
     public void testEmptyArray() throws Exception
     {
         // First: empty array (2 bytes)

cbor/src/test/java/com/fasterxml/jackson/dataformat/cbor/parse/ParserNumbersTest.java

@@ -328,7 +328,7 @@ public void testFloatNumberType() throws IOException {
     }
 
     public void testBigDecimalType() throws IOException {
-        final BigDecimal NR = new BigDecimal("273.15");
+        final BigDecimal NR = new BigDecimal("172.125");
         ByteArrayOutputStream out = new ByteArrayOutputStream();
         CBORGenerator generator = cborGenerator(out);
         generator.writeNumber(NR);
@@ -343,7 +343,20 @@ public void testBigDecimalType() throws IOException {
             assertEquals(NR.intValue(), parser.getIntValue());
             assertNull(parser.nextToken());
         }
-        // Almost good. But [dataformats#139] to consider too...
-        // ... but that'll need to wait for 2.10
+
+        // Almost good. But [dataformats#139] to consider too, see
+        // [https://tools.ietf.org/html/rfc7049#section-2.4.2]
+        final byte[] spec = new byte[] {
+                (byte) 0xC4,  // tag 4
+                (byte) 0x82,  // Array of length 2
+                0x21,  // int -- -2
+                0x19, 0x6a, (byte) 0xb3 // int 27315
+        };
+        try (CBORParser parser = cborParser(spec)) {
+            assertEquals(JsonToken.VALUE_NUMBER_FLOAT, parser.nextToken());
+            assertEquals(NumberType.BIG_DECIMAL, parser.getNumberType());
+            assertEquals(new BigDecimal("273.15"), parser.getDecimalValue());
+            assertNull(parser.nextToken());
+        }
     }
 }

release-notes/VERSION

@@ -8,6 +8,11 @@ Project: jackson-datatypes-binaryModules:
 === Releases ===
 ------------------------------------------------------------------------
 
+2.10.0 (not yet released)
+
+#139: Incorrect decimal fraction representation
+ (reported by wlukowicz@github)
+
 2.9.7 (19-Sep-2018)
 
 #142: (ion) `IonParser.getNumberType()` returns `null` for `IonType.FLOAT`