Added numberparsing

CMakeLists.txt

@@ -9,6 +9,7 @@ set(headers
     src/cpptypesafeenum.h
     src/cpputils.h
     src/delayedconstruction.h
+    src/numberparsing.h
     src/refwhenneeded.h
     src/strutils.h
 )

src/numberparsing.h

@@ -0,0 +1,75 @@
+#pragma once
+
+// system includes
+#include <cstdint>
+#include <optional>
+#include <cstdio>
+#include <inttypes.h>
+
+namespace cpputils {
+template<typename T> constexpr std::optional<T> fromString(std::string_view str) = delete;
+
+template<> constexpr inline std::optional<int8_t> fromString<int8_t>(std::string_view str)
+{
+    int8_t val{};
+    if (std::sscanf(str.data(), "%" SCNi8, &val) == 1)
+        return val;
+    return std::nullopt;
+}
+
+template<> constexpr inline std::optional<uint8_t> fromString<uint8_t>(std::string_view str)
+{
+    uint8_t val{};
+    if (std::sscanf(str.data(), "%" SCNu8, &val) == 1)
+        return val;
+    return std::nullopt;
+}
+
+template<> constexpr inline std::optional<int16_t> fromString<int16_t>(std::string_view str)
+{
+    int16_t val{};
+    if (std::sscanf(str.data(), "%" SCNi16, &val) == 1)
+        return val;
+    return std::nullopt;
+}
+
+template<> constexpr inline std::optional<uint16_t> fromString<uint16_t>(std::string_view str)
+{
+    uint16_t val{};
+    if (std::sscanf(str.data(), "%" SCNu16, &val) == 1)
+        return val;
+    return std::nullopt;
+}
+
+template<> constexpr inline std::optional<int32_t> fromString<int32_t>(std::string_view str)
+{
+    int32_t val{};
+    if (std::sscanf(str.data(), "%" SCNi32, &val) == 1)
+        return val;
+    return std::nullopt;
+}
+
+template<> constexpr inline std::optional<uint32_t> fromString<uint32_t>(std::string_view str)
+{
+    uint32_t val{};
+    if (std::sscanf(str.data(), "%" SCNu32, &val) == 1)
+        return val;
+    return std::nullopt;
+}
+
+template<> constexpr inline std::optional<int64_t> fromString<int64_t>(std::string_view str)
+{
+    int64_t val{};
+    if (std::sscanf(str.data(), "%" SCNi64, &val) == 1)
+        return val;
+    return std::nullopt;
+}
+
+template<> constexpr inline std::optional<uint64_t> fromString<uint64_t>(std::string_view str)
+{
+    uint64_t val{};
+    if (std::sscanf(str.data(), "%" SCNu64, &val) == 1)
+        return val;
+    return std::nullopt;
+}
+} // namespace cpputils