fixing issue 261

fastfloat · Aug 22, 2024 · 311e4c2 · 311e4c2
1 parent 3642e92
commit 311e4c2
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Showing 2 changed files with 14 additions and 2 deletions.
diff --git a/include/fast_float/parse_number.h b/include/fast_float/parse_number.h
@@ -199,7 +199,7 @@ from_chars(UC const *first, UC const *last, T &value,
 template <typename T, typename UC>
 FASTFLOAT_CONSTEXPR20 from_chars_result_t<UC>
 from_chars_advanced(parsed_number_string_t<UC> &pns, T &value) noexcept {
-
+printf("from_chars_advanced\n");
   static_assert(is_supported_float_type<T>(),
                 "only some floating-point types are supported");
   static_assert(is_supported_char_type<UC>(),
@@ -275,11 +275,12 @@ from_chars_advanced(parsed_number_string_t<UC> &pns, T &value) noexcept {
   if (am.power2 < 0) {
     am = digit_comp<T>(pns, am);
   }
-  to_float(pns.negative, am, value);
   // Test for over/underflow.
   if ((pns.mantissa != 0 && am.mantissa == 0 && am.power2 == 0) ||
       am.power2 == binary_format<T>::infinite_power()) {
     answer.ec = std::errc::result_out_of_range;
+  } else {
+    to_float(pns.negative, am, value);
   }
   return answer;
 }

diff --git a/tests/basictest.cpp b/tests/basictest.cpp
@@ -76,6 +76,15 @@ const char *round_name(int d) {
 #define FASTFLOAT_STR(x) #x
 #define SHOW_DEFINE(x) printf("%s='%s'\n", #x, FASTFLOAT_STR(x))
 
+TEST_CASE("issue261") {
+  std::string_view str = "5.47382e-48";
+  float value = 100.0f;
+  auto res = fast_float::from_chars(str.data(), str.data() + str.size(), value, fast_float::general);
+  CHECK_MESSAGE(res.ec == std::errc::result_out_of_range, "value is out of range (interpretation of the standard)");
+  std::cout << "value = " << fHexAndDec(value) << std::endl;
+  CHECK_MESSAGE(value == 100.0f, "value should be unchanged");
+  CHECK_MESSAGE(res.ptr == str.data() + str.size(), "should point to end of matching pattern");
+}
 TEST_CASE("system_info") {
   std::cout << "system info:" << std::endl;
 #ifdef FASTFLOAT_CONSTEXPR_TESTS
@@ -400,6 +409,8 @@ TEST_CASE("full_multiplication") {
   test_full_multiplication(bit << 63, bit << 63, 0u, bit << 62);
 }
 
+
+
 TEST_CASE("issue8") {
   const char *s =
       "3."