Add ability to convert larger numbers without fast_float, write unit tests

include/ss/extract.hpp

@@ -1,13 +1,13 @@
 #pragma once
 
 #include "type_traits.hpp"
+#include <charconv>
 #include <cstring>
 #include <functional>
 #include <optional>
 #include <string>
 #include <string_view>
 #include <variant>
-#include <charconv>
 
 #ifndef SSP_DISABLE_FAST_FLOAT
 #include <fast_float/fast_float.h>
@@ -42,16 +42,23 @@ std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
 template <typename T>
 std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
     const char* const begin, const char* const end) {
+    static_assert(!std::is_same_v<T, long double>,
+                  "Conversion to long double is disabled");
+
     constexpr static auto buff_max = 64;
-    char buff[buff_max];
+    char short_buff[buff_max];
     size_t string_range = std::distance(begin, end);
+    std::string long_buff;
 
+    char* buff;
     if (string_range > buff_max) {
-        return std::nullopt;
+        long_buff = std::string{begin, end};
-    }
+        buff = long_buff.data();
-
+    } else {
-    std::copy_n(begin, string_range, buff);
+        buff = short_buff;
         buff[string_range] = '\0';
+        std::copy_n(begin, string_range, buff);
+    }
 
     T ret;
     char* parse_end = nullptr;
@@ -60,8 +67,6 @@ std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
         ret = std::strtof(buff, &parse_end);
     } else if constexpr (std::is_same_v<T, double>) {
         ret = std::strtod(buff, &parse_end);
-    } else if constexpr (std::is_same_v<T, long double>) {
-        ret = std::strtold(buff, &parse_end);
     }
 
     if (parse_end != buff + string_range) {

test/test_extractions.cpp

@@ -63,11 +63,6 @@ TEST_CASE("extract test functions for numbers with invalid inputs") {
     // random input for float
     CHECK_INVALID_CONVERSION("xxx1", float);
 
-    // number too big
-    CHECK_INVALID_CONVERSION((std::string(40, '1') + "." +
-                              std::string(40, '2')),
-                             double);
-
     // random input for int
     CHECK_INVALID_CONVERSION("xxx1", int);
 
@@ -280,3 +275,20 @@ TEST_CASE("extract test functions for std::variant") {
         }
     }
 }
+
+TEST_CASE("extract test with long number string") {
+    {
+        std::string string_num =
+            std::string(20, '1') + "." + std::string(20, '2');
+
+        CHECK_FLOATING_CONVERSION_LONG_NUMBER(string_num, float, stof);
+        CHECK_FLOATING_CONVERSION_LONG_NUMBER(string_num, double, stod);
+    }
+
+    {
+        std::string string_num =
+            std::string(50, '1') + "." + std::string(50, '2');
+
+        CHECK_FLOATING_CONVERSION_LONG_NUMBER(string_num, double, stod);
+    }
+}

test/test_extractions_without_fast_float.cpp

@@ -29,11 +29,6 @@ TEST_CASE("extract test functions for numbers with invalid inputs without fast "
 
     // random input for float
     CHECK_INVALID_CONVERSION("xxx1", float);
-
-    // number too big
-    CHECK_INVALID_CONVERSION((std::string(40, '1') + "." +
-                              std::string(40, '2')),
-                             double);
 }
 
 TEST_CASE("extract test functions for std::variant without fast float") {
@@ -135,3 +130,20 @@ TEST_CASE("extract test functions for std::variant without fast float") {
         }
     }
 }
+
+TEST_CASE("extract test with long number string without fast float") {
+    {
+        std::string string_num =
+            std::string(20, '1') + "." + std::string(20, '2');
+
+        CHECK_FLOATING_CONVERSION_LONG_NUMBER(string_num, float, stof);
+        CHECK_FLOATING_CONVERSION_LONG_NUMBER(string_num, double, stod);
+    }
+
+    {
+        std::string string_num =
+            std::string(50, '1') + "." + std::string(50, '2');
+
+        CHECK_FLOATING_CONVERSION_LONG_NUMBER(string_num, double, stod);
+    }
+}

test/test_helpers.hpp

@@ -1,10 +1,10 @@
 #pragma once
 #include <ctime>
+#include <filesystem>
 #include <iomanip>
 #include <sstream>
 #include <string>
 #include <vector>
-#include <filesystem>
 
 #ifdef CMAKE_GITHUB_CI
 #include <doctest/doctest.h>
@@ -75,6 +75,18 @@ struct unique_file_name {
         CHECK_LT(std::abs(t.value() - type(-input)), eps);                     \
     }
 
+#define CHECK_FLOATING_CONVERSION_LONG_NUMBER(STRING_NUMBER, TYPE, CONVERTER)  \
+    {                                                                          \
+        auto begin = STRING_NUMBER.c_str();                                    \
+        auto end = begin + STRING_NUMBER.size();                               \
+                                                                               \
+        auto number = ss::to_num<TYPE>(begin, end);                            \
+        REQUIRE(number.has_value());                                           \
+                                                                               \
+        auto expected_number = CONVERTER(STRING_NUMBER);                       \
+        CHECK_EQ(number.value(), expected_number);                             \
+    }
+
 #define CHECK_INVALID_CONVERSION(input, type)                                  \
     {                                                                          \
         std::string s = input;                                                 \