+
−/*
+
− * This Source Code Form is subject to the terms of the Mozilla Public
+
− * License, v. 2.0.  If a copy of the MPL was not distributed with this
+
− * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
− *
+
− * Copyright 1997 - July 2008 CWI, August 2008 - 2016 MonetDB B.V.
+
− */
+
−
+
−package nl.cwi.monetdb.mcl.parser;
+
−
+
−
+
−/**
+
− * The HeaderLineParser is a generic MCLParser that extracts values from
+
− * a metadata header in the MCL protocol either as string or integer
+
− * values.
+
− *
+
− * @author Fabian Groffen <Fabian.Groffen>
+
− */
+
−public class HeaderLineParser extends MCLParser {
+
−	private int type;
+
−
+
−	public final static int NAME       = 1;
+
−	public final static int LENGTH     = 2;
+
−	public final static int TABLE      = 3;
+
−	public final static int TYPE       = 4;
+
−
+
−	/**
+
−	 * Constructs a HeaderLineParser which expects columncount columns.
+
−	 *
+
−	 * @param columncount the number of columns in the to be parsed string
+
−	 */
+
−	public HeaderLineParser(int columncount) {
+
−		super(columncount);
+
−	}
+
−
+
−	/**
+
−	 * Parses the given String source as header line.  If source cannot
+
−	 * be parsed, an MCLParseException is thrown.  The columncount argument
+
−	 * given during construction is used for allocation of the backing
+
−	 * array.  Parsing a header line with has more fields will therefore
+
−	 * result in a crash.  While this seems illogical, the caller should
+
−	 * know this size, since the StartOfHeader contains this
+
−	 * information.
+
−	 *
+
−	 * @param source a String which should be parsed
+
−	 * @return the type of then parsed header line
+
−	 * @throws MCLParseException if an error occurs during parsing
+
−	 */
+
−	@Override
+
−	public int parse(String source) throws MCLParseException {
+
−		char[] chrLine = source.toCharArray();
+
−		int len = chrLine.length;
+
−		int pos = 0;
+
−		boolean foundChar = false;
+
−		boolean nameFound = false;
+
−		// find header name
+
−		for (int i = len - 1; i >= 0; i--) {
+
−			switch (chrLine[i]) {
+
−				case ' ':
+
−				case '\n':
+
−				case '\t':
+
−				case '\r':
+
−					if (!foundChar) {
+
−						len = i - 1;
+
−					} else {
+
−						pos = i + 1;
+
−					}
+
−					break;
+
−				case '#':
+
−					// found!
+
−					nameFound = true;
+
−					if (pos == 0) pos = i + 1;
+
−					i = 0;	// force the loop to terminate
+
−					break;
+
−				default:
+
−					foundChar = true;
+
−					pos = 0;
+
−					break;
+
−			}
+
−		}
+
−		if (!nameFound)
+
−			throw new MCLParseException("invalid header, no header name found", pos);
+
−
+
−		// depending on the name of the header, we continue
+
−		switch (chrLine[pos]) {
+
−			case 'n':
+
−				if (len - pos == 4 &&
+
−						source.regionMatches(pos + 1, "name", 1, 3))
+
−				{
+
−					getValues(chrLine, 2, pos - 3);
+
−					type = NAME;
+
−				}
+
−				break;
+
−			case 'l':
+
−				if (len - pos == 6 &&
+
−						source.regionMatches(pos + 1, "length", 1, 5))
+
−				{
+
−					getIntValues(chrLine, 2, pos - 3);
+
−					type = LENGTH;
+
−				}
+
−				break;
+
−			case 't':
+
−				if (len - pos == 4 &&
+
−						source.regionMatches(pos + 1, "type", 1, 3))
+
−				{
+
−					getValues(chrLine, 2, pos - 3);
+
−					type = TYPE;
+
−				} else if (len - pos == 10 &&
+
−						source.regionMatches(pos + 1, "table_name", 1, 9))
+
−				{
+
−					getValues(chrLine, 2, pos - 3);
+
−					type = TABLE;
+
−				}
+
−				break;
+
−			default:
+
−				throw new MCLParseException("unknown header: " +
+
−						(new String(chrLine, pos, len - pos)));
+
−		}
+
−
+
−		// adjust colno
+
−		reset();
+
−
+
−		return type;
+
−	}
+
−
+
−	/**
+
−	 * Returns an array of Strings containing the values between
+
−	 * ',\t' separators.  Note that no quoting/dequoting is done in this
+
−	 * method.
+
−	 *
+
−	 * @param chrLine a character array holding the input data
+
−	 * @param start where the relevant data starts
+
−	 * @param stop where the relevant data stops
+
−	 */
+
−	final private void getValues(char[] chrLine, int start, int stop) {
+
−		int elem = 0;
+
−
+
−		for (int i = start + 1; i < stop; i++) {
+
−			if (chrLine[i] == '\t' && chrLine[i - 1] == ',') {
+
−				values[elem++] =
+
−					new String(chrLine, start, i - 1 - start);
+
−				start = i + 1;
+
−			}
+
−		}
+
−		// add the left over part
+
−		values[elem++] = new String(chrLine, start, stop - start);
+
−	}
+
−
+
−	/**
+
−	 * Returns an array of ints containing the values between
+
−	 * ',\t' separators.
+
−	 *
+
−	 * @param chrLine a character array holding the input data
+
−	 * @param start where the relevant data starts
+
−	 * @param stop where the relevant data stops
+
−	 */
+
−	final private void getIntValues(char[] chrLine, int start, int stop)
+
−		throws MCLParseException
+
−	{
+
−		int elem = 0;
+
−		int tmp = 0;
+
−
+
−		for (int i = start; i < stop; i++) {
+
−			if (chrLine[i] == ',' && chrLine[i + 1] == '\t') {
+
−				intValues[elem++] = tmp;
+
−				tmp = 0;
+
−				start = i++;
+
−			} else {
+
−				tmp *= 10;
+
−				// note: don't use Character.isDigit() here, because
+
−				// we only want ISO-LATIN-1 digits
+
−				if (chrLine[i] >= '0' && chrLine[i] <= '9') {
+
−					tmp += (int)chrLine[i] - (int)'0';
+
−				} else {
+
−					throw new MCLParseException("expected a digit in " + new String(chrLine) + " at " + i);
+
−				}
+
−			}
+
−		}
+
−		// add the left over part
+
−		intValues[elem++] = tmp;
+
−	}
+
−}