core: implement basic message type

1 files changed, 75 insertions, 0 deletions

diff --git a/src/message.cpp b/src/message.cpp
new file mode 100644
index 0000000..ad76897
--- /dev/null
+++ b/src/message.cpp
@@ -0,0 +1,75 @@
+#include "message.hpp"
+
+#include <iterator>
+#include <ios>
+#include <sstream>
+
+namespace wanda
+{
+
+message::operator std::string() const
+{
+    std::ostringstream buffer{};
+    buffer << source
+           << ':'
+           << command;
+    if(argument.has_value())
+    {
+        buffer << ':' << *argument;
+    }
+    return buffer.str();
+}
+
+std::size_t message::size() const
+{
+    return static_cast<std::string>(*this).size();
+}
+
+template <typename InputIt, typename OutputIt, typename UnaryPredicate>
+OutputIt copy_until(InputIt first, InputIt last, OutputIt out, UnaryPredicate predicate)
+{
+    while (first != last && !predicate(*first))
+    {
+        *out++ = *first++;
+    }
+    return out;
+}
+
+std::istream &operator>>(std::istream &in, message &message)
+{
+    auto pos = std::istream_iterator<char>{in};
+    auto end = std::istream_iterator<char>{};
+    auto buffer = std::string{};
+
+    copy_until(pos, end, std::back_inserter(buffer), [](auto const &c) { return c == ':'; });
+    if (in.eof() || buffer.size() != 1)
+    {
+        in.setstate(std::ios_base::failbit);
+        return in;
+    }
+    message.source = buffer;
+
+    buffer.clear();
+    copy_until(++pos, end, std::back_inserter(buffer), [](auto const &c) { return c == ':'; });
+    if (in.eof())
+    {
+        in.setstate(std::ios_base::failbit);
+    }
+    message.command = buffer;
+
+    buffer.clear();
+    copy(++pos, end, std::back_inserter(buffer));
+    if (buffer.size())
+    {
+       message.argument = std::optional{std::move(buffer)};
+    }
+
+    return in;
+}
+
+std::ostream & operator<<(std::ostream & out, message const & message)
+{
+    return out << static_cast<std::string>(message);
+}
+
+} // namespace wanda
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