+
−/*
+
− * 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 TupleLineParser extracts the values from a given tuple.  The
+
− * number of values that are expected are known upfront to speed up
+
− * allocation and validation.
+
− *
+
− * @author Fabian Groffen <Fabian.Groffen>
+
− */
+
−public class TupleLineParser extends MCLParser {
+
−	/**
+
−	 * Constructs a TupleLineParser which expects columncount columns.
+
−	 *
+
−	 * @param columncount the number of columns in the to be parsed string
+
−	 */
+
−	public TupleLineParser(int columncount) {
+
−		super(columncount);
+
−	}
+
−
+
−	/**
+
−	 * Parses the given String source as tuple line.  If source cannot
+
−	 * be parsed, a ParseException is thrown.  The columncount argument
+
−	 * is used for allocation of the returned array.  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 0, as there is no 'type' of TupleLine
+
−	 * @throws ParseException if an error occurs during parsing
+
−	 */
+
−	@Override
+
−	public int parse(String source) throws MCLParseException {
+
−		int len = source.length();
+
−		char[] chrLine = new char[len];
+
−		source.getChars(0, len, chrLine, 0);
+
−
+
−		// first detect whether this is a single value line (=) or a
+
−		// real tuple ([)
+
−		if (chrLine[0] == '=') {
+
−			if (values.length != 1)
+
−				throw new MCLParseException(values.length +
+
−						" columns expected, but only single value found");
+
−
+
−			// return the whole string but the leading =
+
−			values[0] = source.substring(1);
+
−
+
−			// reset colnr
+
−			reset();
+
−
+
−			return 0;
+
−		}
+
−
+
−		// extract separate fields by examining string, char for char
+
−		boolean inString = false, escaped = false;
+
−		int cursor = 2, column = 0, i = 2;
+
−		StringBuilder uesc = new StringBuilder();
+
−		for (; i < len; i++) {
+
−			switch(chrLine[i]) {
+
−				default:
+
−					escaped = false;
+
−				break;
+
−				case '\\':
+
−					escaped = !escaped;
+
−				break;
+
−				case '"':
+
−					/**
+
−					 * If all strings are wrapped between two quotes, a \" can
+
−					 * never exist outside a string. Thus if we believe that we
+
−					 * are not within a string, we can safely assume we're about
+
−					 * to enter a string if we find a quote.
+
−					 * If we are in a string we should stop being in a string if
+
−					 * we find a quote which is not prefixed by a \, for that
+
−					 * would be an escaped quote. However, a nasty situation can
+
−					 * occur where the string is like "test \\" as obvious, a
+
−					 * test for a \ in front of a " doesn't hold here for all
+
−					 * cases. Because "test \\\"" can exist as well, we need to
+
−					 * know if a quote is prefixed by an escaping slash or not.
+
−					 */
+
−					if (!inString) {
+
−						inString = true;
+
−					} else if (!escaped) {
+
−						inString = false;
+
−					}
+
−
+
−					// reset escaped flag
+
−					escaped = false;
+
−				break;
+
−				case '\t':
+
−					if (!inString &&
+
−						(i > 0 && chrLine[i - 1] == ',') ||
+
−						(i + 1 == len - 1 && chrLine[++i] == ']')) // dirty
+
−					{
+
−						// split!
+
−						if (chrLine[cursor] == '"' &&
+
−							chrLine[i - 2] == '"')
+
−						{
+
−							// reuse the StringBuilder by cleaning it
+
−							uesc.delete(0, uesc.length());
+
−							// prevent capacity increasements
+
−							uesc.ensureCapacity((i - 2) - (cursor + 1));
+
−							for (int pos = cursor + 1; pos < i - 2; pos++) {
+
−								if (chrLine[pos] == '\\' && pos + 1 < i - 2) {
+
−									pos++;
+
−									// strToStr and strFromStr in gdk_atoms.mx only
+
−									// support \t \n \\ \" and \377
+
−									switch (chrLine[pos]) {
+
−										case '\\':
+
−											uesc.append('\\');
+
−										break;
+
−										case 'n':
+
−											uesc.append('\n');
+
−										break;
+
−										case 't':
+
−											uesc.append('\t');
+
−										break;
+
−										case '"':
+
−											uesc.append('"');
+
−										break;
+
−										case '0': case '1': case '2': case '3':
+
−											// this could be an octal number, let's check it out
+
−											if (pos + 2 < i - 2 &&
+
−												chrLine[pos + 1] >= '0' && chrLine[pos + 1] <= '7' &&
+
−												chrLine[pos + 2] >= '0' && chrLine[pos + 2] <= '7'
+
−											) {
+
−												// we got the number!
+
−												try {
+
−													uesc.append((char)(Integer.parseInt("" + chrLine[pos] + chrLine[pos + 1] + chrLine[pos + 2], 8)));
+
−													pos += 2;
+
−												} catch (NumberFormatException e) {
+
−													// hmmm, this point should never be reached actually...
+
−													throw new AssertionError("Flow error, should never try to parse non-number");
+
−												}
+
−											} else {
+
−												// do default action if number seems not to be correct
+
−												uesc.append(chrLine[pos]);
+
−											}
+
−										break;
+
−										default:
+
−											// this is wrong, just ignore the escape, and print the char
+
−											uesc.append(chrLine[pos]);
+
−										break;
+
−									}
+
−								} else {
+
−									uesc.append(chrLine[pos]);
+
−								}
+
−							}
+
−
+
−							// put the unescaped string in the right place
+
−							values[column++] = uesc.toString();
+
−						} else if ((i - 1) - cursor == 4 &&
+
−								source.indexOf("NULL", cursor) == cursor)
+
−						{
+
−							values[column++] = null;
+
−						} else {
+
−							values[column++] =
+
−								source.substring(cursor, i - 1);
+
−						}
+
−						cursor = i + 1;
+
−					}
+
−
+
−					// reset escaped flag
+
−					escaped = false;
+
−				break;
+
−			}
+
−		}
+
−		// check if this result is of the size we expected it to be
+
−		if (column != values.length)
+
−			throw new MCLParseException("illegal result length: " + column + "\nlast read: " + (column > 0 ? values[column - 1] : "<none>"));
+
−
+
−		// reset colnr
+
−		reset();
+
−		
+
−		return 0;
+
−	}
+
−}