fix hang when parsing egregiously long integer (#77)

Author: davidhewitt

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "jiter"
-version = "0.2.0"
+version = "0.2.1"
 edition = "2021"
 description = "Iterable JSON parser"
 readme = "README.md"

Cargo.toml

@@ -224,16 +224,16 @@ impl IntParse {
         // number is too big for i64, we need ot use a big int
         loop {
             let (chunk, new_index) = IntChunk::parse_big(data, index);
+            if (new_index - start) > 4300 {
+                return json_err!(NumberOutOfRange, start + 4301);
+            }
             match chunk {
                 IntChunk::Ongoing(value) => {
                     big_value *= ONGOING_CHUNK_MULTIPLIER;
                     big_value += value;
                     index = new_index;
                 }
                 IntChunk::Done(value) => {
-                    if (new_index - start) > 4300 {
-                        return json_err!(NumberOutOfRange, start + 4301);
-                    }
                     big_value *= POW_10[new_index - index];
                     big_value += value;
                     if !positive {

src/number_decoder.rs

@@ -981,23 +981,18 @@ fn test_4300_int() {
 }
 
 #[test]
-fn test_4302_int_err() {
-    let json = (0..4302).map(|_| "9".to_string()).collect::<Vec<_>>().join("");
-    let bytes = json.as_bytes();
-    let e = JsonValue::parse(bytes, false).unwrap_err();
-    assert_eq!(e.error_type, JsonErrorType::NumberOutOfRange);
-    assert_eq!(e.index, 4301);
-    assert_eq!(e.description(bytes), "number out of range at line 1 column 4302");
-}
-
-#[test]
-fn test_5000_int_err() {
-    let json = ["9"; 5000].join("");
-    let bytes = json.as_bytes();
-    let e = JsonValue::parse(bytes, false).unwrap_err();
-    assert_eq!(e.error_type, JsonErrorType::NumberOutOfRange);
-    assert_eq!(e.index, 4301);
-    assert_eq!(e.description(bytes), "number out of range at line 1 column 4302");
+fn test_big_int_errs() {
+    for json in [
+        &[b'9'; 4302][..],
+        &[b'9'; 5900][..],
+        // If the check is only done at the end, this will hang
+        &[b'9'; 10usize.pow(7)][..],
+    ] {
+        let e = JsonValue::parse(json, false).unwrap_err();
+        assert_eq!(e.error_type, JsonErrorType::NumberOutOfRange);
+        assert_eq!(e.index, 4301);
+        assert_eq!(e.description(json), "number out of range at line 1 column 4302");
+    }
 }
 
 #[test]