Refactored number class out of VariantReader and added documentation

1 files changed, 171 insertions, 0 deletions

diff --git a/src/core/common/Number.hpp b/src/core/common/Number.hpp
new file mode 100644
index 0000000..89a689e
--- /dev/null
+++ b/src/core/common/Number.hpp
@@ -0,0 +1,171 @@
+/*
+    Ousía
+    Copyright (C) 2014, 2015  Benjamin Paaßen, Andreas Stöckel
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file Number.hpp
+ *
+ * Contains the Number class responsible for parsing integers and doubles of
+ * various bases.
+ *
+ * @author Andreas Stöckel (astoecke@techfak.uni-bielefeld.de)
+ */
+
+#include <cstdint>
+#include <string>
+#include <unordered_set>
+
+namespace ousia {
+
+// Forward declarations
+class CharReader;
+class Logger;
+
+/* Class Number */
+
+/**
+ * Class used internally to represent a number (integer or double). The number
+ * is represented by its components (base value a, nominator n, denominator d,
+ * exponent e, sign s and exponent sign sE).
+ */
+class Number {
+private:
+	/**
+	 * State used in the parser state machine
+	 */
+	enum class State {
+		INIT,
+		HAS_MINUS,
+		LEADING_ZERO,
+		LEADING_POINT,
+		INT,
+		HEX,
+		POINT,
+		EXP_INIT,
+		EXP_HAS_MINUS,
+		EXP
+	};
+
+	/**
+	 * Reprsents the part of the number: Base value a, nominator n, exponent e.
+	 */
+	enum class Part { A, N, E };
+
+	/**
+	 * Sign of the number and the exponent.
+	 */
+	int8_t s, sE;
+
+	/**
+	 * Exponent.
+	 */
+	int16_t e;
+
+	/**
+	 * Base value, nominator, denominator
+	 */
+	int64_t a, n, d;
+
+	/**
+	 * Variable specifying whether the parsed number actually was an integer.
+	 */
+	bool validInteger;
+
+	/**
+	 * Appends the value of the character c to the internal number
+	 * representation and reports any errors that might occur.
+	 *
+	 * @param c is the character that should be appended.
+	 * @param base is the current base.
+	 * @param p is the current number part.
+	 * @param reader is the char reader which points at the current reading
+	 * position.
+	 */
+	bool appendChar(char c, int base, Part p, CharReader &reader,
+	                Logger &logger);
+
+public:
+	/**
+	 * Constructor of the number class.
+	 */
+	Number() : s(1), sE(1), e(0), a(0), n(0), d(1), validInteger(true) {}
+
+	/**
+	 * Returns the represented double value.
+	 *
+	 * @return the double value the number is currently representing.
+	 */
+	double doubleValue();
+
+	/**
+	 * Returns the represented integer value. Only a lossless operation, if the
+	 * number is an integer (as can be checked via the isInt method), otherwise
+	 * the exponent and the fractional value will be truncated.
+	 *
+	 * @return the integer value (ignoring any exponent)
+	 */
+	int64_t intValue();
+
+	/**
+	 * Returns true, if the number was a valid integer.
+	 *
+	 * @return true if the number is an integer, false otherwise.
+	 */
+	bool isInt() { return validInteger; }
+
+	/**
+	 * Tries to parse the number from the given stream and loggs any errors to
+	 * the given logger instance. Numbers are terminated by one of the given
+	 * delimiters.
+	 *
+	 * @param reader is the char reader from which the number should be read.
+	 * @param logger is the logger instance to which error messages should be
+	 * written.
+	 * @param delims is a set of characters at which parsing should stop. The
+	 * reader is positioned at the delimiter.
+	 * @return true if parsing was successful, false otherwise.
+	 */
+	bool parse(
+	    CharReader &reader, Logger &logger,
+	    const std::unordered_set<char> &delims = std::unordered_set<char>{});
+
+	/**
+	 * Tries to parse the number from the given string and loggs any errors to
+	 * the given logger instance.
+	 *
+	 * @param str is the string from which the number should be read.
+	 * @param logger is the logger instance to which error messages should be
+	 * written.
+	 * @return true if parsing was successful, false otherwise.
+	 */
+	bool parse(const std::string &str, Logger &logger);
+
+	/**
+	 * Parses a number with a fixed length and the given base.
+	 *
+	 * @param reader is a reference at the char reader from which the number
+	 * should be read.
+	 * @param len is the length of the integer sequence.
+	 * @param base is the base of the number.
+	 * @param logger is the logger instance to which error messages should be
+	 * written.
+	 */
+	bool parseFixedLenInt(CharReader &reader, int len, int base,
+	                      Logger &logger);
+};
+}
+