Roll our own implementation of parse

src/openrct2/core/String.hpp

@@ -11,7 +11,6 @@
 
 #include "../common.h"
 
-#include <charconv>
 #include <cstdarg>
 #include <cstddef>
 #include <optional>
@@ -122,13 +121,31 @@ namespace String
 
     template<typename T> std::optional<T> Parse(std::string_view input)
     {
-        T out;
-        const std::from_chars_result result = std::from_chars(input.data(), input.data() + input.size(), out);
-        if (result.ec == std::errc::invalid_argument || result.ec == std::errc::result_out_of_range)
-        {
+        if (input.size() == 0)
             return std::nullopt;
+
+        T result = 0;
+        for (size_t i = 0; i < input.size(); i++)
+        {
+            auto chr = input[i];
+            if (chr >= '0' && chr <= '9')
+            {
+                auto digit = chr - '0';
+                auto last = result;
+                result = static_cast<T>((result * 10) + digit);
+                if (result <= last)
+                {
+                    // Overflow, number too large for type
+                    return std::nullopt;
+                }
+            }
+            else
+            {
+                // Bad character
+                return std::nullopt;
+            }
         }
-        return out;
+        return result;
     }
 } // namespace String