From fcdca58617caf6a8c034a91588d6abb399be6b57 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Tue, 18 May 2021 00:06:37 +0100
Subject: Initial commit, still lots to do!

---
 lib/rawDataReader.h | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 lib/rawDataReader.h

(limited to 'lib/rawDataReader.h')

diff --git a/lib/rawDataReader.h b/lib/rawDataReader.h
new file mode 100644
index 0000000..0ed2847
--- /dev/null
+++ b/lib/rawDataReader.h
@@ -0,0 +1,76 @@
+#ifndef MYGRATE_RAW_DATA_READER_H
+#define MYGRATE_RAW_DATA_READER_H
+
+#include "helpers.h"
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+#include <ctime>
+#include <mysql.h> // IWYU pragma: keep
+#include <span>
+#include <stdexcept>
+#include <string_view>
+
+#include <mariadb_rpl.h>
+
+namespace MyGrate {
+	struct PackedInteger {
+	};
+	template<typename T> struct type_map {
+		using target = T;
+	};
+	template<> struct type_map<PackedInteger> {
+		using target = uint64_t;
+	};
+
+	class RawDataReader {
+	public:
+		explicit RawDataReader(const void * const d, std::size_t len);
+		explicit RawDataReader(const MARIADB_STRING & str);
+
+		template<typename T, size_t L = sizeof(T)>
+		typename type_map<T>::target
+		readValue()
+		{
+			static_assert(L > 0 && L <= sizeof(T), "Read exceeds target size");
+			return readValue<T>(L);
+		}
+
+		template<typename T>
+		typename type_map<T>::target
+		readValue(size_t L)
+		{
+			verify<std::logic_error>(L > 0 && L <= sizeof(T), "Read exceeds target size");
+			offsetSizeCheck(L);
+			T v {};
+			memcpy(&v, rawdata + offset, L);
+			offset += L;
+			return v;
+		}
+
+		template<typename T>
+		T
+		viewValue(size_t L)
+		{
+			static_assert(sizeof(typename T::value_type) == sizeof(std::byte));
+			offsetSizeCheck(L);
+			T v {reinterpret_cast<const typename T::value_type *>(rawdata + offset), L};
+			offset += L;
+			return v;
+		}
+
+		void discard(size_t);
+
+	private:
+		void offsetSizeCheck(size_t) const;
+
+		const std::byte * const rawdata;
+		const std::size_t len;
+		std::size_t offset {0};
+	};
+
+	template<> uint64_t RawDataReader::readValue<PackedInteger>();
+}
+
+#endif
-- 
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