From c4f2b74e999758b4a95f7f16c2c05c0af8b69de1 Mon Sep 17 00:00:00 2001
From: Madeline Busig <madeline.busig@outlook.com>
Date: Mon, 25 Mar 2024 21:24:28 -0600
Subject: [PATCH] Add string_stream

---
 include/mtl/string_stream.hpp | 142 ++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 include/mtl/string_stream.hpp

diff --git a/include/mtl/string_stream.hpp b/include/mtl/string_stream.hpp
new file mode 100644
index 0000000..0b29b3d
--- /dev/null
+++ b/include/mtl/string_stream.hpp
@@ -0,0 +1,142 @@
+#pragma once
+
+#include "mtl/stream.hpp"
+#include "mtl/string.hpp"
+
+namespace mtl {
+
+/**
+ * \brief Basic string builder
+ *
+ * Mimics std::stringstream basic functionality. Does not provide thorough
+ * formatting options, only decimal/hexadecimal switching. If more extensive
+ * formatting is needed, use mtl::string_streamx instead.
+ *
+ * Variables are piped to the stream using operator<<. The string is buffered
+ * until flush is called, mtl::flush is piped, or mtl::endl is piped.
+ */
+class string_stream {
+	istring& m_str;
+	bool m_hex = false;
+
+public:
+	string_stream(istring& str) : m_str(str) {}
+
+	/**
+	 * \brief Flushes the buffer to the underlying output sequence and
+	 * clears the buffer
+	 *
+	 * By default simply clears the buffer, but can be overriden to
+	 * provide more functionality. This function is called internally when
+	 * mtl::flush and mtl::endl are piped to the stream. The derived
+	 * class must be sure to clear the buffer when finished.
+	 */
+	virtual void flush() {
+		m_str.clear();
+	}
+
+	void clear() {
+		m_str.clear();
+	}
+
+	string_stream& operator<<(const string_view& str) {
+		m_str.append(str);
+		return *this;
+	}
+
+	string_stream& operator<<(char ch) {
+		m_str += ch;
+		return *this;
+	}
+
+	/**
+	 * \brief Appends the signed integer x
+	 *
+	 * Writes the integer in decimal if the stream was piped mtl::dec,
+	 * hexidecimal if the stream was piped mtl::hex. Defaults to mtl::dec.
+	 *
+	 * The template does not need to check that the integer is a boolean
+	 * because booleans are not signed.
+	 */
+	template <typename T, std::enable_if_t<std::is_signed_v<T>, bool> = true>
+	string_stream& operator<<(T x) {
+		string<16> str;
+		m_str.append(to_string(x, str, m_hex));
+
+		return *this;
+	}
+
+	/**
+	 * \brief Appends the unsigned integer x
+	 *
+	 * Writes the integer in decimal if the stream was piped mtl::dec,
+	 * hexidecimal if the stream was piped mtl::hex. Defaults to mtl::dec.
+	 *
+	 * The template must check that the integer is not a boolean because
+	 * std::is_unsigned counts booleans as unsigned integers.
+	 */
+	template <typename T, std::enable_if_t<std::is_unsigned_v<T> && !std::is_same_v<T, bool>, bool> = true>
+	string_stream& operator<<(T x) {
+		string<16> str;
+		m_str.append(to_string(x, str, m_hex));
+
+		return *this;
+	}
+
+	/**
+	 * \brief Appends the boolean x
+	 *
+	 * Writes the boolean as either "true" or "false".
+	 *
+	 * This function needs to be templated otherwise non-boolean arguments
+	 * might be implicitly converted to boolean. Ex. const char* would be
+	 * implicitly converted to boolean instead of mtl::string_view.
+	 */
+	template <typename T, std::enable_if_t<std::is_same_v<T, bool>, bool> = true>
+	string_stream& operator<<(T x) {
+		m_str.append(x ? "true" : "false");
+
+		return *this;
+	}
+
+	/**
+	 * \brief Appends the address of the pointer addr
+	 *
+	 * Always writes the address is hexidecimal format. Does not pad the
+	 * value to the address width.
+	 *
+	 * The template must check that the pointer is not a character pointer
+	 * otherwise C strings will not be converted to a mtl::string_view and
+	 * the address of the string will be printed instead.
+	 */
+	template <typename T, std::enable_if_t<std::is_pointer_v<T>
+	                      && !std::is_same_v<T, char*>
+			      && !std::is_same_v<T, const char*>, bool> = true>
+	string_stream& operator<<(T addr) {
+		string<16> str;
+		m_str.append(to_string(addr, str));
+
+		return *this;
+	}
+
+	string_stream& operator<<(_flush) {
+		flush();
+		return *this;
+	}
+	string_stream& operator<<(_endl) {
+		m_str += '\n';
+		flush();
+		return *this;
+	}
+
+	string_stream& operator<<(_dec) {
+		m_hex = false;
+		return *this;
+	}
+	string_stream& operator<<(_hex) {
+		m_hex = true;
+		return *this;
+	}
+};
+
+} // namespace mtl