package org.orbeon.saxon.tree;

/**
  * System IDs are not held in nodes in the tree, because they are usually the same
  * for a whole document.
  * This class provides a map from element sequence numbers to System IDs: it is
  * linked to the root node of the tree.
  * Note that the System ID is not necessarily the same as the Base URI. The System ID relates
  * to the external entity in which a node was physically located; this provides a default for
  * the Base URI, but this may be modified by specifying an xml:base attribute
  *
  * @author Michael H. Kay
  */

public class SystemIdMap {

    private int[] sequenceNumbers;
    private String[] uris;
    private int allocated;

    public SystemIdMap() {
        sequenceNumbers = new int[4];
        uris = new String[4];
        allocated = 0;
    }

    /**
    * Set the system ID corresponding to a given sequence number
    */

    public void setSystemId(int sequence, String uri) {
        // ignore it if same as previous
        if (allocated>0 && uri.equals(uris[allocated-1])) {
            return;
        }
        if (sequenceNumbers.length <= allocated + 1) {
            int[] s = new int[allocated * 2];
            String[] u = new String[allocated * 2];
            System.arraycopy(sequenceNumbers, 0, s, 0, allocated);
            System.arraycopy(uris, 0, u, 0, allocated);
            sequenceNumbers = s;
            uris = u;
        }
        sequenceNumbers[allocated] = sequence;
        uris[allocated] = uri;
        allocated++;
    }

    /**
    * Get the system ID corresponding to a given sequence number
    */

    public String getSystemId(int sequence) {
        if (allocated==0) return null;
        // could use a binary chop, but it's not important
        for (int i=1; i<allocated; i++) {
            if (sequenceNumbers[i] > sequence) {
                return uris[i-1];
            }
        }
        return uris[allocated-1];
    }


}

//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
// you may not use this file except in compliance with the License. You may obtain a copy of the
// License at http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file.
//
// The Initial Developer of the Original Code is Michael H. Kay.
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
// Contributor(s): none.
//
