add chrono duration fuzzer

fuzzing/chrono.cpp

@@ -0,0 +1,107 @@
+// Copyright (c) 2019, Paul Dreik
+// License: see LICENSE.rst in the fmt root directory
+
+#include <fmt/core.h>
+#include <cstdint>
+#include <stdexcept>
+#include <type_traits>
+#include <vector>
+
+#include <fmt/chrono.h>
+
+template <typename Item,typename Ratio> void doit_impl(const char* formatstring,Item item) {
+  std::chrono::duration<Item, Ratio> value(item); 
+  std::string message = fmt::format(formatstring, value);
+}
+
+//Item is the underlying type for duration (int, long etc)
+template <typename Item> void doit(const uint8_t* Data, std::size_t Size) {
+  const auto N = sizeof(Item);
+  if (Size <= N) {
+    return;
+  }
+  Item item{};
+    std::memcpy(&item, Data, N);
+  Data += N;
+  Size -= N;
+
+  // allocates as tight as possible, making it easier to catch buffer overruns
+  // also, make it null terminated.
+  std::vector<char> buf(Size + 1);
+  std::memcpy(buf.data(), Data, Size);
+ // doit_impl<Item,std::yocto>(buf.data(),item);
+ // doit_impl<Item,std::zepto>(buf.data(),item);
+  doit_impl<Item,std::atto>(buf.data(),item);
+  doit_impl<Item,std::femto>(buf.data(),item);
+  doit_impl<Item,std::pico>(buf.data(),item);
+  doit_impl<Item,std::nano>(buf.data(),item);
+  doit_impl<Item,std::micro>(buf.data(),item);
+  doit_impl<Item,std::milli>(buf.data(),item);
+  doit_impl<Item,std::centi>(buf.data(),item);
+  doit_impl<Item,std::deci>(buf.data(),item);
+  doit_impl<Item,std::deca>(buf.data(),item); 
+ doit_impl<Item,std::kilo>(buf.data(),item);
+  doit_impl<Item,std::mega>(buf.data(),item);  doit_impl<Item,std::giga>(buf.data(),item);  doit_impl<Item,std::tera>(buf.data(),item);  doit_impl<Item,std::peta>(buf.data(),item);  doit_impl<Item,std::exa>(buf.data(),item); 
+// doit_impl<Item,std::zeta>(buf.data(),item);  doit_impl<Item,std::yotta>(buf.data(),item);
+}
+
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, std::size_t Size) {
+  if (Size <= 3) {
+    return 0;
+  }
+
+  const auto first = Data[0];
+  Data++;
+  Size--;
+
+  try {
+    switch (first) {
+    case 1:
+      doit<char>(Data, Size);
+      break;
+    case 2:
+      doit<short>(Data, Size);
+      break;
+    case 3:
+      doit<int>(Data, Size);
+      break;
+    case 4:
+      doit<long>(Data, Size);
+      break;
+    case 5:
+      doit<float>(Data, Size);
+      break;
+    case 6:
+      doit<double>(Data, Size);
+      break;
+    case 7:
+      doit<long double>(Data, Size);
+      break;
+    default:
+      break;
+    }
+  } catch (std::exception& e) {
+  }
+  return 0;
+}
+
+#ifdef IMPLEMENT_MAIN
+#  include <cassert>
+#  include <fstream>
+#  include <sstream>
+#  include <vector>
+int main(int argc, char* argv[]) {
+  for (int i = 1; i < argc; ++i) {
+    std::ifstream in(argv[i]);
+    assert(in);
+    in.seekg(0, std::ios_base::end);
+    const auto pos = in.tellg();
+    in.seekg(0, std::ios_base::beg);
+    std::vector<char> buf(pos);
+    in.read(buf.data(), buf.size());
+    assert(in.gcount() == pos);
+    LLVMFuzzerTestOneInput((const uint8_t*)buf.data(), buf.size());
+  }
+}
+#endif