Implemented ArrayParser and unit tests to verify its working.

pgsql/ArrayParser.h

@@ -0,0 +1,53 @@
+#ifndef ARRAYPARSER_H
+#define ARRAYPARSER_H
+
+#include <optional>
+#include <tuple>
+#include <string>
+#include <string_view>
+
+namespace Pgsql {
+	/** Class for parsing array values coming from postgresql
+	 *
+	 * exceptions are used to report serious errors
+	 * in production these kind of errors should rarely happen as
+	 * they are either a bug in this parser or postgres changed its format.
+	 */
+	class ArrayParser {
+	public:
+		/**
+		 * \param data The string that needs parsing (warning just the pointer is stored, the string is not copied)
+		 */
+		explicit ArrayParser(const char *array_string);
+
+		class NextElemResult {
+		public:
+			bool ok;
+			std::optional<std::string_view> value;
+		};
+		/**
+		 *
+		 * Usage:
+		 *   auto [ok, val] = parser.GetNextElem();
+		 *
+		 * \return the bool signals if there was a next element when it is true or the end of the array in which
+		 *   case it is false. The optional is not set when the next element IS NULL. Otherwise it refers to the
+		 *   string value of the element. If the element was quoted it has been stripped of quotes and escapes.
+		 */
+		NextElemResult GetNextElem();
+	private:
+		const char *data;
+		const char *end;
+		std::string temp; // internal buffer for when a value needs escaping
+		const char *pos;
+
+		void parseQuotedValue();
+		void initializeParse();
+		/** Moves pos forward to the first non whitespace character.
+		 */
+		void skipWhitespace();
+	};
+
+} // end namespace Pgsql
+
+#endif // ARRAYPARSER_H