Merge pull request #185 from boostorg/more_fuzz

Fuzz `to_chars` for integers

fuzzing/fuzz_to_chars_int.cpp

@@ -0,0 +1,60 @@
+// Copyright 2024 Matt Borland
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/charconv.hpp>
+#include <boost/core/detail/string_view.hpp>
+#include <iostream>
+#include <exception>
+
+extern "C" int LLVMFuzzerTestOneInput(const std::uint8_t* data, std::size_t size)
+{
+    try
+    {
+        auto c_data = reinterpret_cast<const char*>(data);
+
+        for (int base = 2; base < 36; ++base)
+        {
+            char buffer[10]; // Small enough it should force overflows
+
+            char c_val {};
+            boost::charconv::from_chars(c_data, c_data + size, c_val, base);
+            boost::charconv::to_chars(buffer, buffer + sizeof(buffer), c_val, base);
+
+            int i_val {};
+            boost::charconv::from_chars(c_data, c_data + size, i_val, base);
+            boost::charconv::to_chars(buffer, buffer + sizeof(buffer), i_val, base);
+
+            long l_val {};
+            boost::charconv::from_chars(c_data, c_data + size, l_val, base);
+            boost::charconv::to_chars(buffer, buffer + sizeof(buffer), l_val, base);
+
+            long long ll_val {};
+            boost::charconv::from_chars(c_data, c_data + size, ll_val, base);
+            boost::charconv::to_chars(buffer, buffer + sizeof(buffer), ll_val, base);
+
+            unsigned char uc_val {};
+            boost::charconv::from_chars(c_data, c_data + size, uc_val, base);
+            boost::charconv::to_chars(buffer, buffer + sizeof(buffer), uc_val, base);
+
+            unsigned int ui_val {};
+            boost::charconv::from_chars(c_data, c_data + size, ui_val, base);
+            boost::charconv::to_chars(buffer, buffer + sizeof(buffer), ui_val, base);
+
+            unsigned long ul_val {};
+            boost::charconv::from_chars(c_data, c_data + size, ul_val, base);
+            boost::charconv::to_chars(buffer, buffer + sizeof(buffer), ul_val, base);
+
+            unsigned long long ull_val {};
+            boost::charconv::from_chars(c_data, c_data + size, ull_val, base);
+            boost::charconv::to_chars(buffer, buffer + sizeof(buffer), ull_val, base);
+        }
+    }
+    catch(...)
+    {
+        std::cerr << "Error with: " << data << std::endl;
+        std::terminate();
+    }
+
+    return 0;
+}