Handle very large and very small numbers with scientific notation #27

Author: maciejhirsz

src/codegen.rs

@@ -51,6 +51,11 @@ pub trait Generator {
             self.write_char(b'-');
         }
 
+        if num > 1e19 || num < 1e-15 {
+            self.write(format!("{:e}", num).as_bytes());
+            return;
+        }
+
         let start = self.current_index();
 
         self.write_digits_from_u64(num as u64);

tests/lib.rs

@@ -137,7 +137,22 @@ fn stringify_integer() {
 
 #[test]
 fn stringify_small_number() {
-    assert_eq!(stringify(0.000000000000001), "0.000000000000001");
+    assert_eq!(stringify(1e-15), "0.000000000000001");
+}
+
+#[test]
+fn stringify_large_number() {
+    assert_eq!(stringify(1e19), "10000000000000000000");
+}
+
+#[test]
+fn stringify_very_large_number() {
+    assert_eq!(stringify(3.141592653589793e20), "3.141592653589793e20");
+}
+
+#[test]
+fn stringify_very_small_number() {
+    assert_eq!(stringify(3.141592653589793e-16), "3.141592653589793e-16");
 }
 
 #[test]