+
−/*
+
− * 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 - 2020 MonetDB B.V.
+
− */
+
−
+
−package nl.cwi.monetdb.mcl.parser;
+
−
+
−import java.nio.CharBuffer;
+
−
+
−/**
+
− * The StartOfHeaderParser allows easy examination of a start of header
+
− * line.  It does not fit into the general MCLParser framework because
+
− * it uses a different interface.  While the parser is very shallow, it
+
− * requires the caller to know about the header lines that are parsed.
+
− * All this parser does is detect the (valid) type of a soheader, and
+
− * allow to return the fields in it as integer or string.  An extra
+
− * bonus is that it can return if another field should be present in the
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− * soheader.
+
− *
+
− * @author Fabian Groffen
+
− */
+
−public final class StartOfHeaderParser {
+
−	private CharBuffer soh = null;
+
−	private int len;
+
−	private int pos;
+
−
+
−	/* Query types (copied from sql_query.mx) */
+
−
+
−	/** A parse response (not handled) */
+
−	public final static int Q_PARSE    = '0';
+
−	/** A tabular response (typical ResultSet) */
+
−	public final static int Q_TABLE    = '1';
+
−	/** A response to an update statement, contains number of affected
+
−	 * rows and generated key-id */
+
−	public final static int Q_UPDATE   = '2';
+
−	/** A response to a schema update */
+
−	public final static int Q_SCHEMA   = '3';
+
−	/** A response to a transation statement (start, rollback, abort,
+
−	 * commit) */
+
−	public final static int Q_TRANS    = '4';
+
−	/** A tabular response in response to a PREPARE statement containing
+
−	 * information about the wildcard values that need to be supplied */
+
−	public final static int Q_PREPARE  = '5';
+
−	/** A tabular continuation response (for a ResultSet) */
+
−	public final static int Q_BLOCK    = '6';
+
−	/** An unknown and unsupported response */
+
−	public final static int Q_UNKNOWN  =  0 ;
+
−
+
−	public final int parse(final String in) throws MCLParseException {
+
−		soh = CharBuffer.wrap(in);
+
−		soh.get();	// skip the &
+
−		final int type = soh.get();
+
−		switch (type) {
+
−			case Q_PARSE:
+
−			case Q_SCHEMA:
+
−				len = 0;
+
−				break;
+
−			case Q_TABLE:
+
−			case Q_PREPARE:
+
−				len = 4;
+
−				soh.get();
+
−				break;
+
−			case Q_UPDATE:
+
−				len = 2;
+
−				soh.get();
+
−				break;
+
−			case Q_TRANS:
+
−				len = 1;
+
−				soh.get();
+
−				break;
+
−			case Q_BLOCK:
+
−				len = 3;
+
−				soh.get();
+
−				break;
+
−			default:
+
−				throw new MCLParseException("invalid or unknown header", 1);
+
−		}
+
−		pos = 0;
+
−		return type;
+
−	}
+
−
+
−	public final boolean hasNext() {
+
−		return pos < len;
+
−	}
+
−
+
−	/**
+
−	 * Returns the next token in the CharBuffer as integer. The value is
+
−	 * considered to end at the end of the CharBuffer or at a space.  If
+
−	 * a non-numeric character is encountered an MCLParseException is
+
−	 * thrown.
+
−	 *
+
−	 * @return The next token in the CharBuffer as integer
+
−	 * @throws MCLParseException if no numeric value could be read
+
−	 */
+
−	public final int getNextAsInt() throws MCLParseException {
+
−		pos++;
+
−		if (!soh.hasRemaining())
+
−			throw new MCLParseException("unexpected end of string", soh.position() - 1);
+
−
+
−		boolean positive = true;
+
−		char chr = soh.get();
+
−		// note: don't use Character.isDigit() here, because
+
−		// we only want ISO-LATIN-1 digits
+
−		if (chr == '-') {
+
−			positive = false;
+
−			if (!soh.hasRemaining())
+
−				throw new MCLParseException("unexpected end of string", soh.position() - 1);
+
−			chr = soh.get();
+
−		}
+
−
+
−		int tmp = 0;
+
−		if (chr >= '0' && chr <= '9') {
+
−			tmp = (int)chr - (int)'0';
+
−		} else {
+
−			throw new MCLParseException("expected a digit", soh.position() - 1);
+
−		}
+
−
+
−		while (soh.hasRemaining() && (chr = soh.get()) != ' ') {
+
−			if (chr >= '0' && chr <= '9') {
+
−				tmp *= 10;
+
−				tmp += (int)chr - (int)'0';
+
−			} else {
+
−				throw new MCLParseException("expected a digit", soh.position() - 1);
+
−			}
+
−		}
+
−
+
−		return positive ? tmp : -tmp;
+
−	}
+
−
+
−	public final String getNextAsString() throws MCLParseException {
+
−		pos++;
+
−		if (!soh.hasRemaining())
+
−			throw new MCLParseException("unexpected end of string", soh.position() - 1);
+
−
+
−		int cnt = 0;
+
−		soh.mark();
+
−		while (soh.hasRemaining() && soh.get() != ' ') {
+
−			cnt++;
+
−		}
+
−		soh.reset();
+
−
+
−		return soh.subSequence(0, cnt).toString();
+
−	}
+
−}