fix #176 parse infinity

Author: taowen

src/main/java/com/jsoniter/IterImplForStreaming.java

@@ -540,6 +540,16 @@ static int readIntSlowPath(final JsonIterator iter, int value) throws IOExceptio
     public static final double readDoubleSlowPath(final JsonIterator iter) throws IOException {
         try {
             numberChars numberChars = readNumber(iter);
+            if (numberChars.charsLength == 0 && iter.whatIsNext() == ValueType.STRING) {
+                String possibleInf = iter.readString();
+                if ("infinity".equals(possibleInf)) {
+                    return Double.POSITIVE_INFINITY;
+                }
+                if ("-infinity".equals(possibleInf)) {
+                    return Double.NEGATIVE_INFINITY;
+                }
+                throw iter.reportError("readDoubleSlowPath", "expect number but found string: " + possibleInf);
+            }
             return Double.valueOf(new String(numberChars.chars, 0, numberChars.charsLength));
         } catch (NumberFormatException e) {
             throw iter.reportError("readDoubleSlowPath", e.toString());

src/main/java/com/jsoniter/output/StreamImplNumber.java

@@ -212,10 +212,18 @@ public static final void writeLong(final JsonStream stream, long value) throws I
 
     public static final void writeFloat(JsonStream stream, float val) throws IOException {
         if (val < 0) {
+            if (val == Float.NEGATIVE_INFINITY) {
+                stream.writeVal("-Infinity");
+                return;
+            }
             stream.write('-');
             val = -val;
         }
         if (val > 0x4ffffff) {
+            if (val == Float.POSITIVE_INFINITY) {
+                stream.writeVal("Infinity");
+                return;
+            }
             stream.writeRaw(Float.toString(val));
             return;
         }
@@ -240,10 +248,18 @@ public static final void writeFloat(JsonStream stream, float val) throws IOExcep
 
     public static final void writeDouble(JsonStream stream, double val) throws IOException {
         if (val < 0) {
+            if (val == Double.NEGATIVE_INFINITY) {
+                stream.writeVal("-Infinity");
+                return;
+            }
             val = -val;
             stream.write('-');
         }
         if (val > 0x4ffffff) {
+            if (val == Double.POSITIVE_INFINITY) {
+                stream.writeVal("Infinity");
+                return;
+            }
             stream.writeRaw(Double.toString(val));
             return;
         }

src/test/java/com/jsoniter/TestFloat.java

@@ -1,6 +1,5 @@
 package com.jsoniter;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
 import junit.framework.TestCase;
 import org.junit.experimental.categories.Category;
 
@@ -90,4 +89,12 @@ public void testChooseDouble() {
         number = JsonIterator.deserialize("1.0", Object.class);
         assertEquals(1.0, number);
     }
+
+    public void testInfinity() {
+        assertTrue(JsonIterator.deserialize("\"-infinity\"", Double.class) == Double.NEGATIVE_INFINITY);
+        assertTrue(JsonIterator.deserialize("\"-infinity\"", Float.class) == Float.NEGATIVE_INFINITY);
+        assertTrue(JsonIterator.deserialize("\"infinity\"", Double.class) == Double.POSITIVE_INFINITY);
+        assertTrue(JsonIterator.deserialize("\"infinity\"", Float.class) == Float.POSITIVE_INFINITY);
+    }
+
 }

src/test/java/com/jsoniter/output/TestFloat.java

@@ -8,4 +8,10 @@ public class TestFloat extends TestCase {
     public void testBigDecimal() {
         assertEquals("100.1", JsonStream.serialize(new BigDecimal("100.1")));
     }
+    public void test_infinity() {
+        assertEquals("\"Infinity\"", JsonStream.serialize(Double.POSITIVE_INFINITY));
+        assertEquals("\"Infinity\"", JsonStream.serialize(Float.POSITIVE_INFINITY));
+        assertEquals("\"-Infinity\"", JsonStream.serialize(Double.NEGATIVE_INFINITY));
+        assertEquals("\"-Infinity\"", JsonStream.serialize(Float.NEGATIVE_INFINITY));
+    }
 }