adds changes for correctly setting stream position when error occurs while reading binary int64

ionc/ion_reader_binary.c

@@ -969,7 +969,7 @@ iERR _ion_reader_binary_read_int64(ION_READER *preader, int64_t *p_value)
 {
     iENTER;
     ION_BINARY_READER *binary;
-    int                tid, len;
+    int                tid, len, i;
     uint64_t           unsignedInt64 = 0;
     BOOL               is_negative;
     BOOL               is_null;
@@ -1006,7 +1006,17 @@ iERR _ion_reader_binary_read_int64(ION_READER *preader, int64_t *p_value)
     IONCHECK(ion_binary_read_uint_64(preader->istream, len, &unsignedInt64));
 
     is_negative = (tid == TID_NEG_INT)? TRUE: FALSE;
-    IONCHECK(cast_to_int64(unsignedInt64, is_negative, p_value));
+    iERR result = cast_to_int64(unsignedInt64, is_negative, p_value);
+
+    // if an error is thrown reset reader stream's current pointer to the beginning of current value again
+    if(result) {
+        i = len;
+        while(i--) {
+            preader->istream->_curr--;
+        }
+        FAILWITH(result);
+    }
+
     if (is_negative && *p_value == 0) {
         FAILWITH(IERR_INVALID_BINARY);
     }

test/test_ion_binary.cpp

@@ -402,6 +402,38 @@ TEST(IonBinaryInt, ReaderRejectsNegativeZeroMixedIntTwoByte) {
     test_ion_binary_write_from_reader_rejects_negative_zero_int((BYTE *)"\xE0\x01\x00\xEA\x31\x00", 6);
 }
 
+void test_ion_binary_reader_threshold_for_int64(BYTE *data, size_t len, char *actual_value) {
+    hREADER reader;
+    ION_TYPE type;
+    int64_t value;
+    ION_INT big_int_expected;
+    SIZE str_len, written;
+
+    ION_ASSERT_OK(ion_reader_open_buffer(&reader, data, len, NULL));
+    ION_ASSERT_OK(ion_reader_next(reader, &type));
+    ASSERT_EQ(tid_INT, type);
+
+    // reading value as int64 will throw numeric overflow error
+    ASSERT_EQ(IERR_NUMERIC_OVERFLOW,ion_reader_read_int64(reader, &value));
+
+    // initialize ION_INT and read it as big integer
+    ION_ASSERT_OK(ion_int_init(&big_int_expected, NULL));
+    ION_ASSERT_OK(ion_reader_read_ion_int(reader, &big_int_expected));
+
+    // convert big integer to string for comparison
+    ion_int_char_length(&big_int_expected, &str_len);
+    char *int_str = (char *)malloc(str_len * sizeof(char));
+    ion_int_to_char(&big_int_expected, (BYTE *)int_str, str_len, &written);
+
+    // compare string representation of the value
+    ASSERT_STREQ(actual_value, int_str);
+}
+
+TEST(IonBinaryReader, ReaderThresholdForInt64) {
+    test_ion_binary_reader_threshold_for_int64((BYTE *)"\xE0\x01\x00\xEA\x28\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 13, "18446744073709551615");
+    test_ion_binary_reader_threshold_for_int64((BYTE *)"\xE0\x01\x00\xEA\x39\x00\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 14, "-18446744073709551615");
+}
+
 void test_ion_binary_reader_requires_timestamp_fraction_less_than_one(BYTE *data, size_t len) {
     hREADER reader;
     ION_TYPE type;