// XmlParser.java: the main parser class.
// NO WARRANTY! See README, and copyright below.
// $Id: XmlParser.java,v 1.3 2004/02/22 20:00:47 spestov Exp $

package com.microstar.xml;

import java.io.BufferedInputStream;
import java.io.EOFException;
import java.io.InputStream;
import java.io.Reader;
import java.net.URL;
import java.net.URLConnection;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Stack;


/**
  * Parse XML documents and return parse events through call-backs.
  * 
You need to define a class implementing the XmlHandler
  * interface: an object belonging to this class will receive the
  * callbacks for the events.  (As an alternative to implementing
  * the full XmlHandler interface, you can simply extend the 
  * HandlerBase convenience class.)
  * 
Usage (assuming that MyHandler is your implementation
  * of the XmlHandler interface):
  * 
  * XmlHandler handler = new MyHandler();
  * XmlParser parser = new XmlParser();
  * parser.setHandler(handler);
  * try {
  *   parser.parse("http://www.host.com/doc.xml", null);
  * } catch (Exception e) {
  *   [do something interesting]
  * }
  * 
  * 
Alternatively, you can use the standard SAX interfaces
  * with the SAXDriver class as your entry point.
  * @author Copyright (c) 1997, 1998 by Microstar Software Ltd.
  * @author Written by David Megginson <dmeggins@microstar.com>
  * @version 1.1
  * @see XmlHandler
  * @see HandlerBase
  * @see SAXDriver
  */
public class XmlParser {

  //
  // Use special cheats that speed up the code (currently about 50%),
  // but may cause problems with future maintenance and add to the
  // class file size (about 500 bytes).
  //
  private final static boolean USE_CHEATS = true;



  //////////////////////////////////////////////////////////////////////
  // Constructors.
  ////////////////////////////////////////////////////////////////////////


  /**
    * Construct a new parser with no associated handler.
    * @see #setHandler
    * @see #parse
    */
  public XmlParser ()
  {
  }


  /**
    * Set the handler that will receive parsing events.
    * @param handler The handler to receive callback events.
    * @see #parse
    * @see XmlHandler
    */
  public void setHandler (XmlHandler handler)
  {
    this.handler = handler;
  }


  /**
    * Parse an XML document from a URI.
    * 
You may parse a document more than once, but only one thread
    * may call this method for an object at one time.
    * @param systemId The URI of the document.
    * @param publicId The public identifier of the document, or null.
    * @param encoding The suggested encoding, or null if unknown.
    * @exception java.lang.Exception Any exception thrown by your
    *            own handlers, or any derivation of java.io.IOException
    *            thrown by the parser itself.
    */
  public void parse (String systemId, String publicId, String encoding)
    throws java.lang.Exception
  {
    doParse(systemId, publicId, null, null, encoding);
  }


  /**
    * Parse an XML document from a byte stream.
    * 
The URI that you supply will become the base URI for
    * resolving relative links, but Ælfred will actually read
    * the document from the supplied input stream.
    * 
You may parse a document more than once, but only one thread
    * may call this method for an object at one time.
    * @param systemId The base URI of the document, or null if not
    *                 known.
    * @param publicId The public identifier of the document, or null
    *                 if not known.
    * @param stream A byte input stream.
    * @param encoding The suggested encoding, or null if unknown.
    * @exception java.lang.Exception Any exception thrown by your
    *            own handlers, or any derivation of java.io.IOException
    *            thrown by the parser itself.
    */
  public void parse (String systemId, String publicId,
		     InputStream stream, String encoding)
    throws java.lang.Exception
  {
    doParse(systemId, publicId, null, stream, encoding);
  }


  /**
    * Parse an XML document from a character stream.
    * 
The URI that you supply will become the base URI for
    * resolving relative links, but Ælfred will actually read
    * the document from the supplied input stream.
    * 
You may parse a document more than once, but only one thread
    * may call this method for an object at one time.
    * @param systemId The base URI of the document, or null if not
    *                 known.
    * @param publicId The public identifier of the document, or null
    *                 if not known.
    * @param reader A character stream.
    * @exception java.lang.Exception Any exception thrown by your
    *            own handlers, or any derivation of java.io.IOException
    *            thrown by the parser itself.
    */
  public void parse (String systemId, String publicId, Reader reader)
    throws java.lang.Exception
  {
    doParse(systemId, publicId, reader, null, null);
  }


  private synchronized void doParse (String systemId, String publicId,
				     Reader reader, InputStream stream,
				     String encoding)
    throws java.lang.Exception
  {
    basePublicId = publicId;
    baseURI = systemId;
    baseReader = reader;
    baseInputStream = stream;

    initializeVariables();

				// Set the default entities here.
    setInternalEntity(intern("amp"), "&");
    setInternalEntity(intern("lt"), "<");
    setInternalEntity(intern("gt"), ">");
    setInternalEntity(intern("apos"), "'");
    setInternalEntity(intern("quot"), """);

    if (handler != null) {
      handler.startDocument();
    }

    pushURL("[document]", basePublicId, baseURI, baseReader, baseInputStream,
	    encoding);

    parseDocument();

    if (handler != null) {
      handler.endDocument();
    }
    cleanupVariables();
  }



  ////////////////////////////////////////////////////////////////////////
  // Constants.
  ////////////////////////////////////////////////////////////////////////

  //
  // Constants for element content type.
  //

  /**
    * Constant: an element has not been declared.
    * @see #getElementContentType
    */
  public final static int CONTENT_UNDECLARED = 0;

  /**
    * Constant: the element has a content model of ANY.
    * @see #getElementContentType
    */
  public final static int CONTENT_ANY = 1;

  /**
    * Constant: the element has declared content of EMPTY.
    * @see #getElementContentType
    */
  public final static int CONTENT_EMPTY = 2;

  /**
    * Constant: the element has mixed content.
    * @see #getElementContentType
    */
  public final static int CONTENT_MIXED = 3;

  /**
    * Constant: the element has element content.
    * @see #getElementContentType
    */
  public final static int CONTENT_ELEMENTS = 4;


  //
  // Constants for the entity type.
  //

  /**
    * Constant: the entity has not been declared.
    * @see #getEntityType
    */
  public final static int ENTITY_UNDECLARED = 0;

  /**
    * Constant: the entity is internal.
    * @see #getEntityType
    */
  public final static int ENTITY_INTERNAL = 1;

  /**
    * Constant: the entity is external, non-XML data.
    * @see #getEntityType
    */
  public final static int ENTITY_NDATA = 2;

  /**
    * Constant: the entity is external XML data.
    * @see #getEntityType
    */
  public final static int ENTITY_TEXT = 3;


  //
  // Constants for attribute type.
  //

  /**
    * Constant: the attribute has not been declared for this element type.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_UNDECLARED = 0;

  /**
    * Constant: the attribute value is a string value.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_CDATA = 1;

  /**
    * Constant: the attribute value is a unique identifier.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_ID = 2;

  /**
    * Constant: the attribute value is a reference to a unique identifier.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_IDREF = 3;

  /**
    * Constant: the attribute value is a list of ID references.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_IDREFS = 4;

  /**
    * Constant: the attribute value is the name of an entity.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_ENTITY = 5;

  /**
    * Constant: the attribute value is a list of entity names.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_ENTITIES = 6;

  /**
    * Constant: the attribute value is a name token.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_NMTOKEN = 7;

  /**
    * Constant: the attribute value is a list of name tokens.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_NMTOKENS = 8;

  /**
    * Constant: the attribute value is a token from an enumeration.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_ENUMERATED = 9;

  /**
    * Constant: the attribute is the name of a notation.
    * @see #getAttributeType
    */
  public final static int ATTRIBUTE_NOTATION = 10;


  //
  // When the class is loaded, populate the hash table of
  // attribute types.
  //

  /**
    * Hash table of attribute types.
    */
  private static Hashtable attributeTypeHash;
  static {
    attributeTypeHash = new Hashtable();
    attributeTypeHash.put("CDATA", new Integer(ATTRIBUTE_CDATA));
    attributeTypeHash.put("ID", new Integer(ATTRIBUTE_ID));
    attributeTypeHash.put("IDREF", new Integer(ATTRIBUTE_IDREF));
    attributeTypeHash.put("IDREFS", new Integer(ATTRIBUTE_IDREFS));
    attributeTypeHash.put("ENTITY", new Integer(ATTRIBUTE_ENTITY));
    attributeTypeHash.put("ENTITIES", new Integer(ATTRIBUTE_ENTITIES));
    attributeTypeHash.put("NMTOKEN", new Integer(ATTRIBUTE_NMTOKEN));
    attributeTypeHash.put("NMTOKENS", new Integer(ATTRIBUTE_NMTOKENS));
    attributeTypeHash.put("NOTATION", new Integer(ATTRIBUTE_NOTATION));
  }


  //
  // Constants for supported encodings.
  //
  private final static int ENCODING_UTF_8 = 1;
  private final static int ENCODING_ISO_8859_1 = 2;
  private final static int ENCODING_UCS_2_12 = 3;
  private final static int ENCODING_UCS_2_21 = 4;
  private final static int ENCODING_UCS_4_1234 = 5;
  private final static int ENCODING_UCS_4_4321 = 6;
  private final static int ENCODING_UCS_4_2143 = 7;
  private final static int ENCODING_UCS_4_3412 = 8;


  //
  // Constants for attribute default value.
  //

  /**
    * Constant: the attribute is not declared.
    * @see #getAttributeDefaultValueType
    */
  public final static int ATTRIBUTE_DEFAULT_UNDECLARED = 0;

  /**
    * Constant: the attribute has a literal default value specified.
    * @see #getAttributeDefaultValueType
    * @see #getAttributeDefaultValue
    */
  public final static int ATTRIBUTE_DEFAULT_SPECIFIED = 1;

  /**
    * Constant: the attribute was declared #IMPLIED.
    * @see #getAttributeDefaultValueType
    */
  public final static int ATTRIBUTE_DEFAULT_IMPLIED = 2;

  /**
    * Constant: the attribute was declared #REQUIRED.
    * @see #getAttributeDefaultValueType
    */
  public final static int ATTRIBUTE_DEFAULT_REQUIRED = 3;

  /**
    * Constant: the attribute was declared #FIXED.
    * @see #getAttributeDefaultValueType
    * @see #getAttributeDefaultValue
    */
  public final static int ATTRIBUTE_DEFAULT_FIXED = 4;


  //
  // Constants for input.
  //
  private final static int INPUT_NONE = 0;
  private final static int INPUT_INTERNAL = 1;
  private final static int INPUT_EXTERNAL = 2;
  private final static int INPUT_STREAM = 3;
  private final static int INPUT_BUFFER = 4;
  private final static int INPUT_READER = 5;


  //
  // Flags for reading literals.
  //
  private final static int LIT_CHAR_REF = 1;
  private final static int LIT_ENTITY_REF = 2;
  private final static int LIT_PE_REF = 4;
  private final static int LIT_NORMALIZE = 8;


  //
  // Flags for parsing context.
  //
  private final static int CONTEXT_NONE = 0;
  private final static int CONTEXT_DTD = 1;
  private final static int CONTEXT_ENTITYVALUE = 2;
  private final static int CONTEXT_ATTRIBUTEVALUE = 3;



  //////////////////////////////////////////////////////////////////////
  // Error reporting.
  //////////////////////////////////////////////////////////////////////


  /**
    * Report an error.
    * @param message The error message.
    * @param textFound The text that caused the error (or null).
    * @see XmlHandler#error
    * @see #line
    */
  void error (String message, String textFound, String textExpected)
    throws java.lang.Exception
  {
    errorCount++;
    if (textFound != null) {
      message = message + " (found \"" + textFound + "\")";
    }
    if (textExpected != null) {
      message = message + " (expected \"" + textExpected + "\")";
    }
    if (handler != null) {
      String uri = null;

      if (externalEntity != null) {
	uri = externalEntity.getURL().toString();
      }
      handler.error(message, uri, line, column);
    }
  }


  /**
    * Report a serious error.
    * @param message The error message.
    * @param textFound The text that caused the error (or null).
    */
  void error (String message, char textFound, String textExpected)
    throws java.lang.Exception
  {
    error(message, new Character(textFound).toString(), textExpected);
  }



  //////////////////////////////////////////////////////////////////////
  // Major syntactic productions.
  //////////////////////////////////////////////////////////////////////


  /**
    * Parse an XML document.
    * 
    * [1] document ::= prolog element Misc*
    * 
    * 
This is the top-level parsing function for a single XML
    * document.  As a minimum, a well-formed document must have
    * a document element, and a valid document must have a prolog
    * as well.
    */
  void parseDocument ()
    throws java.lang.Exception
    {
    char c;

    parseProlog();
    require('<');
    parseElement();
    try
      {
      parseMisc();  //skip all white, PIs, and comments
      c=readCh();   //if this doesn't throw an exception...
      error("unexpected characters after document end",c,null);
      }
    catch (EOFException e)
      {return;}
    }


  /**
    * Skip a comment.
    * 
    * [18] Comment ::= '<!--' ((Char - '-') | ('-' (Char - '-')))* "-->"
    * 
    * 
(The <!-- has already been read.)
    */
  void parseComment ()
    throws java.lang.Exception
  {
    skipUntil("-->");
  }


  /**
    * Parse a processing instruction and do a call-back.
    * 
    * [19] PI ::= '<?' Name (S (Char* - (Char* '?>' Char*)))? '?>'
    * 
    * 
(The <? has already been read.)
    * 
An XML processing instruction must begin with
    * a Name, which is the instruction's target.
    */
  void parsePI ()
    throws java.lang.Exception
  {
    String name;

    name = readNmtoken(true);
    if (!tryRead("?>")) {
      requireWhitespace();
      parseUntil("?>");
    }
    if (handler != null) {
      handler.processingInstruction(name, dataBufferToString());
    }
  }


  /**
    * Parse a CDATA marked section.
    * 
    * [20] CDSect ::= CDStart CData CDEnd
    * [21] CDStart ::= '<![CDATA['
    * [22] CData ::= (Char* - (Char* ']]>' Char*))
    * [23] CDEnd ::= ']]>'
    * 
    * 
(The '<![CDATA[' has already been read.)
    * 
Note that this just appends characters to the dataBuffer,
    * without actually generating an event.
    */
  void parseCDSect ()
    throws java.lang.Exception
  {
    parseUntil("]]>");
  }


  /**
    * Parse the prolog of an XML document.
    * 
    * [24] prolog ::= XMLDecl? Misc* (Doctypedecl Misc*)?
    * 
    * 
There are a couple of tricks here.  First, it is necessary to
    * declare the XML default attributes after the DTD (if present)
    * has been read.  Second, it is not possible to expand general
    * references in attribute value literals until after the entire
    * DTD (if present) has been parsed.
    * 
We do not look for the XML declaration here, because it is
    * handled by pushURL().
    * @see pushURL
    */
  void parseProlog ()
    throws java.lang.Exception
  {
    parseMisc();

    if (tryRead("
    * [25] XMLDecl ::= '<?xml' VersionInfo EncodingDecl? SDDecl? S? '?>'
    * [26] VersionInfo ::= S 'version' Eq ('"1.0"' | "'1.0'")
    * [33] SDDecl ::= S 'standalone' Eq "'" ('yes' | 'no') "'"
    *               | S 'standalone' Eq '"' ("yes" | "no") '"'
    * [78] EncodingDecl ::= S 'encoding' Eq QEncoding
    * 

([80] to [82] are also significant.) *

(The <?xml and whitespace have already been read.) *

TODO: validate value of standalone. * @see #parseTextDecl * @see #checkEncoding */ void parseXMLDecl (boolean ignoreEncoding) throws java.lang.Exception { String version; String encodingName = null; String standalone = null; // Read the version. require("version"); parseEq(); version = readLiteral(0); if (!version.equals("1.0")) { error("unsupported XML version", version, "1.0"); } // Try reading an encoding declaration. skipWhitespace(); if (tryRead("encoding")) { parseEq(); encodingName = readLiteral(0); checkEncoding(encodingName, ignoreEncoding); } // Try reading a standalone declaration skipWhitespace(); if (tryRead("standalone")) { parseEq(); standalone = readLiteral(0); } skipWhitespace(); require("?>"); } /** * Parse the Encoding PI. *

    * [78] EncodingDecl ::= S 'encoding' Eq QEncoding
    * [79] EncodingPI ::= '<?xml' S 'encoding' Eq QEncoding S? '?>'
    * [80] QEncoding ::= '"' Encoding '"' | "'" Encoding "'"
    * [81] Encoding ::= LatinName
    * [82] LatinName ::= [A-Za-z] ([A-Za-z0-9._] | '-')*
    * 

(The <?xml' and whitespace have already been read.) * @see #parseXMLDecl * @see #checkEncoding */ void parseTextDecl (boolean ignoreEncoding) throws java.lang.Exception { String encodingName = null; // Read an optional version. if (tryRead("version")) { String version; parseEq(); version = readLiteral(0); if (!version.equals("1.0")) { error("unsupported XML version", version, "1.0"); } requireWhitespace(); } // Read the encoding. require("encoding"); parseEq(); encodingName = readLiteral(0); checkEncoding(encodingName, ignoreEncoding); skipWhitespace(); require("?>"); } /** * Check that the encoding specified makes sense. *

Compare what the author has specified in the XML declaration * or encoding PI with what we have detected. *

This is also important for distinguishing among the various * 7- and 8-bit encodings, such as ISO-LATIN-1 (I cannot autodetect * those). * @param encodingName The name of the encoding specified by the user. * @see #parseXMLDecl * @see #parseTextDecl */ void checkEncoding (String encodingName, boolean ignoreEncoding) throws java.lang.Exception { encodingName = encodingName.toUpperCase(); if (ignoreEncoding) { return; } switch (encoding) { // 8-bit encodings case ENCODING_UTF_8: if (encodingName.equals("ISO-8859-1")) { encoding = ENCODING_ISO_8859_1; } else if (!encodingName.equals("UTF-8")) { error("unsupported 8-bit encoding", encodingName, "UTF-8 or ISO-8859-1"); } break; // 16-bit encodings case ENCODING_UCS_2_12: case ENCODING_UCS_2_21: if (!encodingName.equals("ISO-10646-UCS-2") && !encodingName.equals("UTF-16")) { error("unsupported 16-bit encoding", encodingName, "ISO-10646-UCS-2"); } break; // 32-bit encodings case ENCODING_UCS_4_1234: case ENCODING_UCS_4_4321: case ENCODING_UCS_4_2143: case ENCODING_UCS_4_3412: if (!encodingName.equals("ISO-10646-UCS-4")) { error("unsupported 32-bit encoding", encodingName, "ISO-10646-UCS-4"); } } } /** * Parse miscellaneous markup outside the document element and DOCTYPE * declaration. *

    * [27] Misc ::= Comment | PI | S
    * 

(The <!DOCTYPE has already been read.) */ void parseDoctypedecl () throws java.lang.Exception { char c; String doctypeName, ids[]; // Read the document type name. requireWhitespace(); doctypeName = readNmtoken(true); // Read the ExternalIDs. skipWhitespace(); ids = readExternalIds(false); // Look for a declaration subset. skipWhitespace(); if (tryRead('[')) { // loop until the subset ends while (true) { context = CONTEXT_DTD; skipWhitespace(); context = CONTEXT_NONE; if (tryRead(']')) { break; // end of subset } else { context = CONTEXT_DTD; parseMarkupdecl(); context = CONTEXT_NONE; } } } // Read the external subset, if any if (ids[1] != null) { pushURL("[external subset]", ids[0], ids[1], null, null, null); // Loop until we end up back at '>' while (true) { context = CONTEXT_DTD; skipWhitespace(); context = CONTEXT_NONE; if (tryRead('>')) { break; } else { context = CONTEXT_DTD; parseMarkupdecl(); context = CONTEXT_NONE; } } } else { // No external subset. skipWhitespace(); require('>'); } if (handler != null) { handler.doctypeDecl(doctypeName, ids[0], ids[1]); } // Expand general entities in // default values of attributes. // (Do this after the doctypeDecl // event!). // expandAttributeDefaultValues(); } /** * Parse a markup declaration in the internal or external DTD subset. *

    * [29] markupdecl ::= ( %elementdecl | %AttlistDecl | %EntityDecl |
    *                       %NotationDecl | %PI | %S | %Comment |
    *                       InternalPERef )
    * [30] InternalPERef ::= PEReference
    * [31] extSubset ::= (%markupdecl | %conditionalSect)*
    * 

(The '<' has already been read.) *

NOTE: this method actually chains onto parseContent(), if necessary, * and parseContent() will take care of calling parseETag(). */ void parseElement () throws java.lang.Exception { String gi; char c; int oldElementContent = currentElementContent; String oldElement = currentElement; // This is the (global) counter for the // array of specified attributes. tagAttributePos = 0; // Read the element type name. gi = readNmtoken(true); // Determine the current content type. currentElement = gi; currentElementContent = getElementContentType(gi); if (currentElementContent == CONTENT_UNDECLARED) { currentElementContent = CONTENT_ANY; } // Read the attributes, if any. // After this loop, we should be just // in front of the closing delimiter. skipWhitespace(); c = readCh(); while (c != '/' && c != '>') { unread(c); parseAttribute(gi); skipWhitespace(); c = readCh(); } unread(c); // Supply any defaulted attributes. Enumeration atts = declaredAttributes(gi); if (atts != null) { String aname; loop: while (atts.hasMoreElements()) { aname = (String)atts.nextElement(); // See if it was specified. for (int i = 0; i < tagAttributePos; i++) { if (tagAttributes[i] == aname) { continue loop; } } // I guess not... if (handler != null) { handler.attribute(aname, getAttributeExpandedValue(gi, aname), false); } } } // Figure out if this is a start tag // or an empty element, and dispatch an // event accordingly. c = readCh(); switch (c) { case '>': if (handler != null) { handler.startElement(gi); } parseContent(); break; case '/': require('>'); if (handler != null) { handler.startElement(gi); handler.endElement(gi); } break; } // Restore the previous state. currentElement = oldElement; currentElementContent = oldElementContent; } /** * Parse an attribute assignment. *

    * [34] Attribute ::= Name Eq AttValue
    * 

    * [16] PCData ::= [^<&]*
    * 

The trick here is that the data stays in the dataBuffer without * necessarily being converted to a string right away. */ void parsePCData () throws java.lang.Exception { char c; // Start with a little cheat -- in most // cases, the entire sequence of // character data will already be in // the readBuffer; if not, fall through to // the normal approach. if (USE_CHEATS) { int lineAugment = 0; int columnAugment = 0; loop: for (int i = readBufferPos; i < readBufferLength; i++) { switch (readBuffer[i]) { case '\n': lineAugment++; columnAugment = 0; break; case '&': case '<': int start = readBufferPos; columnAugment++; readBufferPos = i; if (lineAugment > 0) { line += lineAugment; column = columnAugment; } else { column += columnAugment; } dataBufferAppend(readBuffer, start, i-start); return; default: columnAugment++; } } } // OK, the cheat didn't work; start over // and do it by the book. while (true) { c = readCh(); switch (c) { case '<': case '&': unread(c); return; default: dataBufferAppend(c); break; } } }  ////////////////////////////////////////////////////////////////////// // High-level reading and scanning methods. ////////////////////////////////////////////////////////////////////// /** * Require whitespace characters. * [1] S ::= (#x20 | #x9 | #xd | #xa)+ */ void requireWhitespace () throws java.lang.Exception { char c = readCh(); if (isWhitespace(c)) { skipWhitespace(); } else { error("whitespace expected", c, null); } } /** * Parse whitespace characters, and leave them in the data buffer. */ void parseWhitespace () throws java.lang.Exception { char c = readCh(); while (isWhitespace(c)) { dataBufferAppend(c); c = readCh(); } unread(c); } /** * Skip whitespace characters. * [1] S ::= (#x20 | #x9 | #xd | #xa)+ */ void skipWhitespace () throws java.lang.Exception { // Start with a little cheat. Most of // the time, the white space will fall // within the current read buffer; if // not, then fall through. if (USE_CHEATS) { int lineAugment = 0; int columnAugment = 0; loop: for (int i = readBufferPos; i < readBufferLength; i++) { switch (readBuffer[i]) { case ' ': case '\t': case '\r': columnAugment++; break; case '\n': lineAugment++; columnAugment = 0; break; case '%': if (context == CONTEXT_DTD || context == CONTEXT_ENTITYVALUE) { break loop; } // else fall through... default: readBufferPos = i; if (lineAugment > 0) { line += lineAugment; column = columnAugment; } else { column += columnAugment; } return; } } } // OK, do it by the book. char c = readCh(); while (isWhitespace(c)) { c = readCh(); } unread(c); } /** * Read a name or name token. * [5] Name ::= (Letter | '_' | ':') (NameChar)* * [7] Nmtoken ::= (NameChar)+ * *NOTE: [6] is implemented implicitly where required. */ String readNmtoken (boolean isName) throws java.lang.Exception { char c; if (USE_CHEATS) { loop: for (int i = readBufferPos; i < readBufferLength; i++) { switch (readBuffer[i]) { case '%': if (context == CONTEXT_DTD || context == CONTEXT_ENTITYVALUE) { break loop; } // else fall through... case '<': case '>': case '&': case ',': case '|': case '*': case '+': case '?': case ')': case '=': case '\'': case '"': case '[': case ' ': case '\t': case '\r': case '\n': case ';': case '/': case '#': int start = readBufferPos; if (i == start) { error("name expected", readBuffer[i], null); } readBufferPos = i; return intern(readBuffer, start, i - start); } } } nameBufferPos = 0; // Read the first character. loop: while (true) { c = readCh(); switch (c) { case '%': case '<': case '>': case '&': case ',': case '|': case '*': case '+': case '?': case ')': case '=': case '\'': case '"': case '[': case ' ': case '\t': case '\n': case '\r': case ';': case '/': unread(c); if (nameBufferPos == 0) { error("name expected", null, null); } String s = intern(nameBuffer,0,nameBufferPos); nameBufferPos = 0; return s; default: nameBuffer = (char[])extendArray(nameBuffer, nameBuffer.length, nameBufferPos); nameBuffer[nameBufferPos++] = c; } } } /** * Read a literal. * [10] AttValue ::= '"' ([^<&"] | Reference)* '"' * | "'" ([^<&'] | Reference)* "'" * [11] SystemLiteral ::= '"' URLchar* '"' | "'" (URLchar - "'")* "'" * [13] PubidLiteral ::= '"' PubidChar* '"' | "'" (PubidChar - "'")* "'" * [9] EntityValue ::= '"' ([^%&"] | PEReference | Reference)* '"' * | "'" ([^%&'] | PEReference | Reference)* "'" */ String readLiteral (int flags) throws java.lang.Exception { char delim, c; int startLine = line; // Find the delimiter. delim = readCh(); if (delim != '"' && delim != '\'' && delim != (char)0) { error("expected '\"' or \"'\"", delim, null); return null; } // Read the literal. try { c = readCh(); loop: while (c != delim) { switch (c) { // Literals never have line ends case '\n': case '\r': c = ' '; break; // References may be allowed case '&': if ((flags & LIT_CHAR_REF) > 0) { c = readCh(); if (c == '#') { parseCharRef(); c = readCh(); continue loop; // check the next character } else if ((flags & LIT_ENTITY_REF) > 0) { unread(c); parseEntityRef(false); c = readCh(); continue loop; } else { dataBufferAppend('&'); } } break; default: break; } dataBufferAppend(c); c = readCh(); } } catch (EOFException e) { error("end of input while looking for delimiter (started on line " + startLine + ')', null, new Character(delim).toString()); } // Normalise whitespace if necessary. if ((flags & LIT_NORMALIZE) > 0) { dataBufferNormalize(); } // Return the value. return dataBufferToString(); } /** * Try reading external identifiers. *

The system identifier is not required for notations. * @param inNotation Are we in a notation? * @return A two-member String array containing the identifiers. */ String[] readExternalIds (boolean inNotation) throws java.lang.Exception { char c; String ids[] = new String[2]; if (tryRead("PUBLIC")) { requireWhitespace(); ids[0] = readLiteral(LIT_NORMALIZE); // public id if (inNotation) { skipWhitespace(); if (tryRead('"') || tryRead('\'')) { ids[1] = readLiteral(0); } } else { requireWhitespace(); ids[1] = readLiteral(0); // system id } } else if (tryRead("SYSTEM")) { requireWhitespace(); ids[1] = readLiteral(0); // system id } return ids; } /** * Test if a character is whitespace. *

    * [1] S ::= (#x20 | #x9 | #xd | #xa)+
    * 

Ælfred uses this method to create an internalised version * of all names and attribute values, so that it can test equality * with == instead of String.equals(). *

If you want to be able to test for equality in the same way, * you can use this method to internalise your own strings first: *

    * String PARA = handler.intern("PARA");
    * 

Note that this will not return the same results as String.intern(). * @param s The string to internalise. * @return An internalised version of the string. * @see #intern(char[],int,int) * @see java.lang.String#intern */ public String intern (String s) { char ch[] = s.toCharArray(); return intern(ch, 0, ch.length); } /** * Create an internalised string from a character array. *

This is much more efficient than constructing a non-internalised * string first, and then internalising it. *

Note that this will not return the same results as String.intern(). * @param ch an array of characters for building the string. * @param start the starting position in the array. * @param length the number of characters to place in the string. * @return an internalised string. * @see #intern(String) * @see java.lang.String#intern */ public String intern (char ch[], int start, int length) { int index; int hash = 0; // Generate a hash code. for (int i = start; i < start + length; i++) { hash = ((hash << 1) & 0xffffff) + (int)ch[i]; } hash = hash % SYMBOL_TABLE_LENGTH; // Get the bucket. Object bucket[] = (Object[])symbolTable[hash]; if (bucket == null) { symbolTable[hash] = bucket = new Object[8]; } // Search for a matching tuple, and // return the string if we find one. for (index = 0; index < bucket.length; index += 2) { char chFound[] = (char[])bucket[index]; // Stop when we hit a null index. if (chFound == null) { break; } // If they're the same length, // check for a match. // If the loop finishes, 'index' will // contain the current bucket // position. if (chFound.length == length) { for (int i = 0; i < chFound.length; i++) { // Stop if there are no more tuples. if (ch[start+i] != chFound[i]) { break; } else if (i == length-1) { // That's it, we have a match! return (String)bucket[index+1]; } } } } // Not found -- we'll have to add it. // Do we have to grow the bucket? bucket = (Object[])extendArray(bucket, bucket.length, index); // OK, add it to the end of the // bucket. String s = new String(ch, start, length); bucket[index] = s.toCharArray(); bucket[index+1] = s; symbolTable[hash] = bucket; return s; } /** * Ensure the capacity of an array, allocating a new one if * necessary. */ Object extendArray (Object array, int currentSize, int requiredSize) { if (requiredSize < currentSize) { return array; } else { Object newArray = null; int newSize = currentSize * 2; if (newSize <= requiredSize) { newSize = requiredSize + 1; } if (array instanceof char[]) { newArray = new char[newSize]; } else if (array instanceof Object[]) { newArray = new Object[newSize]; } System.arraycopy(array, 0, newArray, 0, currentSize); return newArray; } }  ////////////////////////////////////////////////////////////////////// // XML query routines. ////////////////////////////////////////////////////////////////////// // // Elements // /** * Get the declared elements for an XML document. *

The results will be valid only after the DTD (if any) has been * parsed. * @return An enumeration of all element types declared for this * document (as Strings). * @see #getElementContentType * @see #getElementContentModel */ public Enumeration declaredElements () { return elementInfo.keys(); } /** * Look up the content type of an element. * @param name The element type name. * @return An integer constant representing the content type. * @see #getElementContentModel * @see #CONTENT_UNDECLARED * @see #CONTENT_ANY * @see #CONTENT_EMPTY * @see #CONTENT_MIXED * @see #CONTENT_ELEMENTS */ public int getElementContentType (String name) { Object element[] = (Object[])elementInfo.get(name); if (element == null) { return CONTENT_UNDECLARED; } else { return ((Integer)element[0]).intValue(); } } /** * Look up the content model of an element. *

The result will always be null unless the content type is * CONTENT_ELEMENTS or CONTENT_MIXED. * @param name The element type name. * @return The normalised content model, as a string. * @see #getElementContentType */ public String getElementContentModel (String name) { Object element[] = (Object[])elementInfo.get(name); if (element == null) { return null; } else { return (String)element[1]; } } /** * Register an element. * Array format: * element type * attribute hash table */ void setElement (String name, int contentType, String contentModel, Hashtable attributes) throws java.lang.Exception { Object element[]; // Try looking up the element element = (Object[])elementInfo.get(name); // Make a new one if necessary. if (element == null) { element = new Object[3]; element[0] = new Integer(CONTENT_UNDECLARED); element[1] = null; element[2] = null; } else if (contentType != CONTENT_UNDECLARED && ((Integer)element[0]).intValue() != CONTENT_UNDECLARED) { error("multiple declarations for element type", name, null); return; } // Insert the content type, if any. if (contentType != CONTENT_UNDECLARED) { element[0] = new Integer(contentType); } // Insert the content model, if any. if (contentModel != null) { element[1] = contentModel; } // Insert the attributes, if any. if (attributes != null) { element[2] =attributes; } // Save the element info. elementInfo.put(name,element); } /** * Look up the attribute hash table for an element. * The hash table is the second item in the element array. */ Hashtable getElementAttributes (String name) { Object element[] = (Object[])elementInfo.get(name); if (element == null) { return null; } else { return (Hashtable)element[2]; } } // // Attributes // /** * Get the declared attributes for an element type. * @param elname The name of the element type. * @return An Enumeration of all the attributes declared for * a specific element type. The results will be valid only * after the DTD (if any) has been parsed. * @see #getAttributeType * @see #getAttributeEnumeration * @see #getAttributeDefaultValueType * @see #getAttributeDefaultValue * @see #getAttributeExpandedValue */ public Enumeration declaredAttributes (String elname) { Hashtable attlist = getElementAttributes(elname); if (attlist == null) { return null; } else { return attlist.keys(); } } /** * Retrieve the declared type of an attribute. * @param name The name of the associated element. * @param aname The name of the attribute. * @return An integer constant representing the attribute type. * @see #ATTRIBUTE_UNDECLARED * @see #ATTRIBUTE_CDATA * @see #ATTRIBUTE_ID * @see #ATTRIBUTE_IDREF * @see #ATTRIBUTE_IDREFS * @see #ATTRIBUTE_ENTITY * @see #ATTRIBUTE_ENTITIES * @see #ATTRIBUTE_NMTOKEN * @see #ATTRIBUTE_NMTOKENS * @see #ATTRIBUTE_ENUMERATED * @see #ATTRIBUTE_NOTATION */ public int getAttributeType (String name, String aname) { Object attribute[] = getAttribute(name, aname); if (attribute == null) { return ATTRIBUTE_UNDECLARED; } else { return ((Integer)attribute[0]).intValue(); } } /** * Retrieve the allowed values for an enumerated attribute type. * @param name The name of the associated element. * @param aname The name of the attribute. * @return A string containing the token list. * @see #ATTRIBUTE_ENUMERATED * @see #ATTRIBUTE_NOTATION */ public String getAttributeEnumeration (String name, String aname) { Object attribute[] = getAttribute(name, aname); if (attribute == null) { return null; } else { return (String)attribute[3]; } } /** * Retrieve the default value of a declared attribute. * @param name The name of the associated element. * @param aname The name of the attribute. * @return The default value, or null if the attribute was * #IMPLIED or simply undeclared and unspecified. * @see #getAttributeExpandedValue */ public String getAttributeDefaultValue (String name, String aname) { Object attribute[] = getAttribute(name, aname); if (attribute == null) { return null; } else { return (String)attribute[1]; } } /** * Retrieve the expanded value of a declared attribute. *

All general entities will be expanded. * @param name The name of the associated element. * @param aname The name of the attribute. * @return The expanded default value, or null if the attribute was * #IMPLIED or simply undeclared * @see #getAttributeDefaultValue */ public String getAttributeExpandedValue (String name, String aname) { Object attribute[] = getAttribute(name, aname); if (attribute == null) { return null; } else if (attribute[4] == null && attribute[1] != null) { try { pushString(null, (char)0 + (String)attribute[1] + (char)0); attribute[4] = readLiteral(LIT_NORMALIZE | LIT_CHAR_REF | LIT_ENTITY_REF); } catch (Exception e) {} } return (String)attribute[4]; } /** * Retrieve the default value type of a declared attribute. * @see #ATTRIBUTE_DEFAULT_SPECIFIED * @see #ATTRIBUTE_DEFAULT_IMPLIED * @see #ATTRIBUTE_DEFAULT_REQUIRED * @see #ATTRIBUTE_DEFAULT_FIXED */ public int getAttributeDefaultValueType (String name, String aname) { Object attribute[] = getAttribute(name, aname); if (attribute == null) { return ATTRIBUTE_DEFAULT_UNDECLARED; } else { return ((Integer)attribute[2]).intValue(); } } /** * Register an attribute declaration for later retrieval. * Format: * - String type * - String default value * - int value type * *TODO: do something with attribute types. */ void setAttribute (String elName, String name, int type, String enumeration, String value, int valueType) throws java.lang.Exception { Hashtable attlist; Object attribute[]; // Create a new hashtable if necessary. attlist = getElementAttributes(elName); if (attlist == null) { attlist = new Hashtable(); } // Check that the attribute doesn't // already exist! if (attlist.get(name) != null) { return; } else { attribute = new Object[5]; attribute[0] = new Integer(type); attribute[1] = value; attribute[2] = new Integer(valueType); attribute[3] = enumeration; attribute[4] = null; attlist.put(name.intern(), attribute); // Use CONTENT_UNDECLARED to avoid overwriting // existing element declaration. setElement(elName,CONTENT_UNDECLARED, null, attlist); } } /** * Retrieve the three-member array representing an * attribute declaration. */ Object[] getAttribute (String elName, String name) { Hashtable attlist; Object attribute[]; attlist = getElementAttributes(elName); if (attlist == null) { return null; } attribute = (Object[])attlist.get(name); return attribute; } // // Entities // /** * Get declared entities. * @return An Enumeration of all the entities declared for * this XML document. The results will be valid only * after the DTD (if any) has been parsed. * @see #getEntityType * @see #getEntityPublicId * @see #getEntitySystemId * @see #getEntityValue * @see #getEntityNotationName */ public Enumeration declaredEntities () { return entityInfo.keys(); } /** * Find the type of an entity. * @returns An integer constant representing the entity type. * @see #ENTITY_UNDECLARED * @see #ENTITY_INTERNAL * @see #ENTITY_NDATA * @see #ENTITY_TEXT */ public int getEntityType (String ename) { Object entity[] = (Object[])entityInfo.get(ename); if (entity == null) { return ENTITY_UNDECLARED; } else { return ((Integer)entity[0]).intValue(); } } /** * Return an external entity's public identifier, if any. * @param ename The name of the external entity. * @return The entity's system identifier, or null if the * entity was not declared, if it is not an * external entity, or if no public identifier was * provided. * @see #getEntityType */ public String getEntityPublicId (String ename) { Object entity[] = (Object[])entityInfo.get(ename); if (entity == null) { return null; } else { return (String)entity[1]; } } /** * Return an external entity's system identifier. * @param ename The name of the external entity. * @return The entity's system identifier, or null if the * entity was not declared, or if it is not an * external entity. * @see #getEntityType */ public String getEntitySystemId (String ename) { Object entity[] = (Object[])entityInfo.get(ename); if (entity == null) { return null; } else { return (String)entity[2]; } } /** * Return the value of an internal entity. * @param ename The name of the internal entity. * @return The entity's value, or null if the entity was * not declared, or if it is not an internal entity. * @see #getEntityType */ public String getEntityValue (String ename) { Object entity[] = (Object[])entityInfo.get(ename); if (entity == null) { return null; } else { return (String)entity[3]; } } /** * Get the notation name associated with an NDATA entity. * @param ename The NDATA entity name. * @return The associated notation name, or null if the * entity was not declared, or if it is not an * NDATA entity. * @see #getEntityType */ public String getEntityNotationName (String eName) { Object entity[] = (Object[])entityInfo.get(eName); if (entity == null) { return null; } else { return (String)entity[4]; } } /** * Register an entity declaration for later retrieval. */ void setInternalEntity (String eName, String value) { setEntity(eName, ENTITY_INTERNAL, null, null, value, null); } /** * Register an external data entity. */ void setExternalDataEntity (String eName, String pubid, String sysid, String nName) { setEntity(eName, ENTITY_NDATA, pubid, sysid, null, nName); } /** * Register an external text entity. */ void setExternalTextEntity (String eName, String pubid, String sysid) { setEntity(eName, ENTITY_TEXT, pubid, sysid, null, null); } /** * Register an entity declaration for later retrieval. */ void setEntity (String eName, int eClass, String pubid, String sysid, String value, String nName) { Object entity[]; if (entityInfo.get(eName) == null) { entity = new Object[5]; entity[0] = new Integer(eClass); entity[1] = pubid; entity[2] = sysid; entity[3] = value; entity[4] = nName; entityInfo.put(eName,entity); } } // // Notations. // /** * Get declared notations. * @return An Enumeration of all the notations declared for * this XML document. The results will be valid only * after the DTD (if any) has been parsed. * @see #getNotationPublicId * @see #getNotationSystemId */ public Enumeration declaredNotations () { return notationInfo.keys(); } /** * Look up the public identifier for a notation. * You will normally use this method to look up a notation * that was provided as an attribute value or for an NDATA entity. * @param nname The name of the notation. * @return A string containing the public identifier, or null * if none was provided or if no such notation was * declared. * @see #getNotationSystemId */ public String getNotationPublicId (String nname) { Object notation[] = (Object[])notationInfo.get(nname); if (notation == null) { return null; } else { return (String)notation[0]; } } /** * Look up the system identifier for a notation. * You will normally use this method to look up a notation * that was provided as an attribute value or for an NDATA entity. * @param nname The name of the notation. * @return A string containing the system identifier, or null * if no such notation was declared. * @see #getNotationPublicId */ public String getNotationSystemId (String nname) { Object notation[] = (Object[])notationInfo.get(nname); if (notation == null) { return null; } else { return (String)notation[1]; } } /** * Register a notation declaration for later retrieval. * Format: * - public id * - system id */ void setNotation (String nname, String pubid, String sysid) throws java.lang.Exception { Object notation[]; if (notationInfo.get(nname) == null) { notation = new Object[2]; notation[0] = pubid; notation[1] = sysid; notationInfo.put(nname,notation); } else { error("multiple declarations of notation", nname, null); } } // // Location. // /** * Return the current line number. */ public int getLineNumber () { return line; } /** * Return the current column number. */ public int getColumnNumber () { return column; }  ////////////////////////////////////////////////////////////////////// // High-level I/O. ////////////////////////////////////////////////////////////////////// /** * Read a single character from the readBuffer. *

The readDataChunk() method maintains the buffer. *

If we hit the end of an entity, try to pop the stack and * keep going. *

(This approach doesn't really enforce XML's rules about * entity boundaries, but this is not currently a validating * parser). *

This routine also attempts to keep track of the current * position in external entities, but it's not entirely accurate. * @return The next available input character. * @see #unread(char) * @see #unread(String) * @see #readDataChunk * @see #readBuffer * @see #line * @return The next character from the current input source. */ char readCh () throws java.lang.Exception { char c; // As long as there's nothing in the // read buffer, try reading more data // (for an external entity) or popping // the entity stack (for either). while (readBufferPos >= readBufferLength) { switch (sourceType) { case INPUT_READER: case INPUT_EXTERNAL: case INPUT_STREAM: readDataChunk(); while (readBufferLength < 1) { popInput(); if (readBufferLength <1) { readDataChunk(); } } break; default: popInput(); break; } } c = readBuffer[readBufferPos++]; // This is a particularly nasty bit // of code, that checks for a parameter // entity reference but peeks ahead to // catch the '%' in parameter entity // declarations. if ( c == '%' && (context == CONTEXT_DTD || context == CONTEXT_ENTITYVALUE) ) { char c2 = readCh(); unread(c2); if (!isWhitespace(c2)) { parsePEReference(context == CONTEXT_ENTITYVALUE); return readCh(); } } if (c == '\n') { line++; column = 0; } else { column++; } return c; } /** * Push a single character back onto the current input stream. *

This method usually pushes the character back onto * the readBuffer, while the unread(String) method treats the * string as a new internal entity. *

I don't think that this would ever be called with * readBufferPos = 0, because the methods always reads a character * before unreading it, but just in case, I've added a boundary * condition. * @param c The character to push back. * @see #readCh * @see #unread(String) * @see #unread(char[]) * @see #readBuffer */ void unread (char c) throws java.lang.Exception { // Normal condition. if (c == '\n') { line--; column = -1; } if (readBufferPos > 0) { readBuffer[--readBufferPos] = c; } else { pushString(null, new Character(c).toString()); } } /** * Push a char array back onto the current input stream. *

NOTE: you must never push back characters that you * haven't actually read: use pushString() instead. * @see #readCh * @see #unread(char) * @see #unread(String) * @see #readBuffer * @see #pushString */ void unread (char ch[], int length) throws java.lang.Exception { for (int i = 0; i < length; i++) { if (ch[i] == '\n') {line--;column = -1;} } if (length < readBufferPos) {readBufferPos -= length;} else { pushCharArray(null, ch, 0, length); sourceType = INPUT_BUFFER; } } /** * Push a new external input source. *

The source will be either an external text entity, or the DTD * external subset. *

TO DO: Right now, this method always attempts to autodetect * the encoding; in the future, it should allow the caller to * request an encoding explicitly, and it should also look at the * headers with an HTTP connection. * @param url The java.net.URL object for the entity. * @see XmlHandler#resolveEntity * @see #pushString * @see #sourceType * @see #pushInput * @see #detectEncoding * @see #sourceType * @see #readBuffer */ void pushURL (String ename, String publicId, String systemId, Reader reader, InputStream stream, String encoding) throws java.lang.Exception { URL url; boolean ignoreEncoding = false; // Push the existing status. pushInput(ename); // Create a new read buffer. // (Note the four-character margin) readBuffer = new char[READ_BUFFER_MAX+4]; readBufferPos = 0; readBufferLength = 0; readBufferOverflow = -1; is = null; line = 1; currentByteCount = 0; // Flush any remaining data. dataBufferFlush(); // Make the URL absolute. if (systemId != null && externalEntity != null) { systemId = new URL(externalEntity.getURL(), systemId).toString(); } else if (baseURI != null) { try { systemId = new URL(new URL(baseURI), systemId).toString(); } catch (Exception e) {} } // See if the application wants to // redirect the system ID and/or // supply its own character stream. if (systemId != null && handler != null) { Object input = handler.resolveEntity(publicId, systemId); if (input != null) { if (input instanceof String) { systemId = (String)input; } else if (input instanceof InputStream) { stream = (InputStream)input; } else if (input instanceof Reader) { reader = (Reader)input; } } } // Start the entity. if (handler != null) { if (systemId != null) { handler.startExternalEntity(systemId); } else { handler.startExternalEntity("[external stream]"); } } // Figure out what we're reading from. if (reader != null) { // There's an explicit character stream. sourceType = INPUT_READER; this.reader = reader; tryEncodingDecl(true); return; } else if (stream != null) { sourceType = INPUT_STREAM; is = stream; } else { // We have to open our own stream // to the URL. // Set the new status sourceType = INPUT_EXTERNAL; url = new URL(systemId); externalEntity = url.openConnection(); externalEntity.connect(); is = externalEntity.getInputStream(); } // If we get to here, there must be // an InputStream available. if (!is.markSupported()) { is = new BufferedInputStream(is); } // Attempt to detect the encoding. if (encoding == null && externalEntity != null) { encoding = externalEntity.getContentEncoding(); } if (encoding != null) { checkEncoding(encoding, false); ignoreEncoding = true; } else { detectEncoding(); ignoreEncoding = false; } // Read an XML or text declaration. tryEncodingDecl(ignoreEncoding); } /** * Check for an encoding declaration. */ void tryEncodingDecl (boolean ignoreEncoding) throws java.lang.Exception { // Read the XML/Encoding declaration. if (tryRead(" 0) { parseTextDecl(ignoreEncoding); } else { parseXMLDecl(ignoreEncoding); } } else { unread("xml".toCharArray(), 3); parsePI(); } } } /** * Attempt to detect the encoding of an entity. *

The trick here (as suggested in the XML standard) is that * any entity not in UTF-8, or in UCS-2 with a byte-order mark, * must begin with an XML declaration or an encoding * declaration; we simply have to look for "<?XML" in various * encodings. *

This method has no way to distinguish among 8-bit encodings. * Instead, it assumes UTF-8, then (possibly) revises its assumption * later in checkEncoding(). Any ASCII-derived 8-bit encoding * should work, but most will be rejected later by checkEncoding(). *

I don't currently detect EBCDIC, since I'm concerned that it * could also be a valid UTF-8 sequence; I'll have to do more checking * later. * @see #tryEncoding(byte[], byte, byte, byte, byte) * @see #tryEncoding(byte[], byte, byte) * @see #checkEncoding * @see #read8bitEncodingDeclaration */ void detectEncoding () throws java.lang.Exception { byte signature[] = new byte[4]; // Read the first four bytes for // autodetection. is.mark(4); is.read(signature); is.reset(); // Look for a known signature. if (tryEncoding(signature, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x3c)) { // UCS-4 must begin with "Utility routine for detectEncoding(). *

Always looks for some part of "Looks for a UCS-2 byte-order mark. *

Utility routine for detectEncoding(). * @param sig The first four bytes read. * @param b1 The first byte of the signature * @param b2 The second byte of the signature * @see #detectEncoding */ boolean tryEncoding (byte sig[], byte b1, byte b2) { return ((sig[0] == b1) && (sig[1] == b2)); } /** * This method pushes a string back onto input. *

It is useful either as the expansion of an internal entity, * or for backtracking during the parse. *

Call pushCharArray() to do the actual work. * @param s The string to push back onto input. * @see #pushCharArray */ void pushString (String ename, String s) throws java.lang.Exception { char ch[] = s.toCharArray(); pushCharArray(ename, ch, 0, ch.length); } /** * Push a new internal input source. *

This method is useful for expanding an internal entity, * or for unreading a string of characters. It creates a new * readBuffer containing the characters in the array, instead * of characters converted from an input byte stream. *

I've added a couple of optimisations: don't push zero- * length strings, and just push back a single character * for 1-character strings; this should save some time and memory. * @param ch The char array to push. * @see #pushString * @see #pushURL * @see #readBuffer * @see #sourceType * @see #pushInput */ void pushCharArray (String ename, char ch[], int start, int length) throws java.lang.Exception { // Push the existing status pushInput(ename); sourceType = INPUT_INTERNAL; readBuffer = ch; readBufferPos = start; readBufferLength = length; readBufferOverflow = -1; } /** * Save the current input source onto the stack. *

This method saves all of the global variables associated with * the current input source, so that they can be restored when a new * input source has finished. It also tests for entity recursion. *

The method saves the following global variables onto a stack * using a fixed-length array: *

*
1. sourceType *
2. externalEntity *
3. readBuffer *
4. readBufferPos *
5. readBufferLength *
6. line *
7. encoding *

This method restores all of the global variables associated with * the current input source. * @exception java.io.EOFException * If there are no more entries on the input stack. * @see #pushInput * @see #sourceType * @see #externalEntity * @see #readBuffer * @see #readBufferPos * @see #readBufferLength * @see #line * @see #encoding */ void popInput () throws java.lang.Exception { Object input[]; switch (sourceType) { case INPUT_EXTERNAL: dataBufferFlush(); if (handler != null && externalEntity != null) { handler.endExternalEntity(externalEntity.getURL().toString()); } break; case INPUT_STREAM: dataBufferFlush(); if (baseURI != null) { if (handler != null) { handler.endExternalEntity(baseURI); } } break; case INPUT_READER: dataBufferFlush(); if (baseURI != null) { if (handler != null) { handler.endExternalEntity(baseURI); } } break; } // Throw an EOFException if there // is nothing else to pop. if (inputStack.isEmpty()) { throw new EOFException(); } else { String s; input = (Object[])inputStack.pop(); s = (String)entityStack.pop(); } sourceType = ((Integer)input[0]).intValue(); externalEntity = (URLConnection)input[1]; readBuffer = (char[])input[2]; readBufferPos = ((Integer)input[3]).intValue(); readBufferLength = ((Integer)input[4]).intValue(); line = ((Integer)input[5]).intValue(); encoding = ((Integer)input[6]).intValue(); readBufferOverflow = ((Integer)input[7]).intValue(); is = (InputStream)input[8]; currentByteCount = ((Integer)input[9]).intValue(); column = ((Integer)input[10]).intValue(); reader = (Reader)input[11]; } /** * Return true if we can read the expected character. *

Note that the character will be removed from the input stream * on success, but will be put back on failure. Do not attempt to * read the character again if the method succeeds. * @param delim The character that should appear next. For a * insensitive match, you must supply this in upper-case. * @return true if the character was successfully read, or false if * it was not. * @see #tryRead(String) */ boolean tryRead (char delim) throws java.lang.Exception { char c; // Read the character c = readCh(); // Test for a match, and push the character // back if the match fails. if (c == delim) { return true; } else { unread(c); return false; } } /** * Return true if we can read the expected string. *

This is simply a convenience method. *

Note that the string will be removed from the input stream * on success, but will be put back on failure. Do not attempt to * read the string again if the method succeeds. *

This method will push back a character rather than an * array whenever possible (probably the majority of cases). *

NOTE: This method currently has a hard-coded limit * of 100 characters for the delimiter. * @param delim The string that should appear next. * @return true if the string was successfully read, or false if * it was not. * @see #tryRead(char) */ boolean tryRead (String delim) throws java.lang.Exception { char ch[] = delim.toCharArray(); char c; // Compare the input, character- // by character. for (int i = 0; i < ch.length; i++) { c=readCh(); if (c!=ch[i]) { unread(c); if (i!=0) {unread(ch,i);} return false; } } return true; } /** * Return true if we can read some whitespace. *

This is simply a convenience method. *

This method will push back a character rather than an * array whenever possible (probably the majority of cases). * @return true if whitespace was found. */ boolean tryWhitespace () throws java.lang.Exception { char c; c = readCh(); if (isWhitespace(c)) { skipWhitespace(); return true; } else { unread(c); return false; } } /** * Read all data until we find the specified string. *

This is especially useful for scanning marked sections. *

This is a a little inefficient right now, since it calls tryRead() * for every character. * @param delim The string delimiter * @see #tryRead(String, boolean) * @see #readCh */ void parseUntil (String delim) throws java.lang.Exception { char c; int startLine = line; try { while (!tryRead(delim)) { c = readCh(); dataBufferAppend(c); } } catch (EOFException e) { error("end of input while looking for delimiter (started on line " + startLine + ')', null, delim); } } /** * Skip all data until we find the specified string. *

This is especially useful for scanning comments. *

This is a a little inefficient right now, since it calls tryRead() * for every character. * @param delim The string delimiter * @see #tryRead(String, boolean) * @see #readCh */ void skipUntil (String delim) throws java.lang.Exception { while (!tryRead(delim)) { readCh(); } } /** * Read just the encoding declaration (or XML declaration) at the * start of an external entity. * When this method is called, we know that the declaration is * present (or appears to be). We also know that the entity is * in some sort of ASCII-derived 8-bit encoding. * The idea of this is to let us read what the 8-bit encoding is * before we've committed to converting any more of the file; the * XML or encoding declaration must be in 7-bit ASCII, so we're * safe as long as we don't go past it. */ void read8bitEncodingDeclaration () throws java.lang.Exception { int ch; readBufferPos = readBufferLength = 0; while (true) { ch = is.read(); readBuffer[readBufferLength++] = (char)ch; switch (ch) { case (int)'>': return; case -1: error("end of file before end of XML or encoding declaration.", null, "?>"); return; } if (readBuffer.length == readBufferLength) { error("unfinished XML or encoding declaration", null, null); } } }  ////////////////////////////////////////////////////////////////////// // Low-level I/O. ////////////////////////////////////////////////////////////////////// /** * Read a chunk of data from an external input source. *

This is simply a front-end that fills the rawReadBuffer * with bytes, then calls the appropriate encoding handler. * @see #encoding * @see #rawReadBuffer * @see #readBuffer * @see #filterCR * @see #copyUtf8ReadBuffer * @see #copyIso8859_1ReadBuffer * @see #copyUcs_2ReadBuffer * @see #copyUcs_4ReadBuffer */ void readDataChunk () throws java.lang.Exception { int count, i, j; // See if we have any overflow. if (readBufferOverflow > -1) { readBuffer[0] = (char)readBufferOverflow; readBufferOverflow = -1; readBufferPos = 1; sawCR = true; } else { readBufferPos = 0; sawCR = false; } // Special situation -- we're taking // input from a character stream. if (sourceType == INPUT_READER) { count = reader.read(readBuffer, readBufferPos, READ_BUFFER_MAX-1); if (count < 0) {readBufferLength = -1;} else { readBufferLength = readBufferPos+count; filterCR(); sawCR = false; } return; } // Read as many bytes as possible // into the read buffer. count = is.read(rawReadBuffer, 0, READ_BUFFER_MAX); // Dispatch to an encoding-specific // reader method to populate the // readBuffer. switch (encoding) { case ENCODING_UTF_8: copyUtf8ReadBuffer(count); break; case ENCODING_ISO_8859_1: copyIso8859_1ReadBuffer(count); break; case ENCODING_UCS_2_12: copyUcs2ReadBuffer(count, 8, 0); break; case ENCODING_UCS_2_21: copyUcs2ReadBuffer(count, 0, 8); break; case ENCODING_UCS_4_1234: copyUcs4ReadBuffer(count, 24, 16, 8, 0); break; case ENCODING_UCS_4_4321: copyUcs4ReadBuffer(count, 0, 8, 16, 24); break; case ENCODING_UCS_4_2143: copyUcs4ReadBuffer(count, 16, 24, 0, 8); break; case ENCODING_UCS_4_3412: copyUcs4ReadBuffer(count, 8, 0, 24, 16); break; } // Filter out all carriage returns // if we've seen any. if (sawCR) { filterCR(); sawCR = false; } // Reset the position. readBufferPos = 0; currentByteCount += count; } /** * Filter carriage returns in the read buffer. *

CRLF becomes LF; CR becomes LF. * @see #readDataChunk * @see #readBuffer * @see #readBufferOverflow */ void filterCR () { int i, j; readBufferOverflow = -1; loop: for (i = 0, j = 0; j < readBufferLength; i++, j++) { switch (readBuffer[j]) { case '\r': if (j == readBufferLength - 1) { readBufferOverflow = '\r'; readBufferLength--; break loop; } else if (readBuffer[j+1] == '\n') {j++;} readBuffer[i] = '\n'; break; case '\n': default: readBuffer[i] = readBuffer[j]; break; } } readBufferLength = i; } /** * Convert a buffer of UTF-8-encoded bytes into UTF-16 characters. *

When readDataChunk() calls this method, the raw bytes are in * rawReadBuffer, and the final characters will appear in * readBuffer. *

The tricky part of this is dealing with UTF-8 multi-byte * sequences, but it doesn't seem to slow things down too much. * @param count The number of bytes to convert. * @see #readDataChunk * @see #rawReadBuffer * @see #readBuffer * @see #getNextUtf8Byte */ void copyUtf8ReadBuffer (int count) throws java.lang.Exception { int i = 0; int j = readBufferPos; int b1; boolean isSurrogate = false; while (i < count) { b1 = rawReadBuffer[i++]; isSurrogate = false; // Determine whether we are dealing // with a one-, two-, three-, or four- // byte sequence. if ((b1 & 0x80) == 0) { // 1-byte sequence: 000000000xxxxxxx = 0xxxxxxx readBuffer[j++] = (char)b1; } else if ((b1 & 0xe0) == 0xc0) { // 2-byte sequence: 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx readBuffer[j++] = (char)(((b1 & 0x1f) << 6) | getNextUtf8Byte(i++, count)); } else if ((b1 & 0xf0) == 0xe0) { // 3-byte sequence: zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx readBuffer[j++] = (char)(((b1 & 0x0f) << 12) | (getNextUtf8Byte(i++, count) << 6) | getNextUtf8Byte(i++, count)); } else if ((b1 & 0xf8) == 0xf0) { // 4-byte sequence: 11101110wwwwzzzzyy + 110111yyyyxxxxxx // = 11110uuu 10uuzzzz 10yyyyyy 10xxxxxx // (uuuuu = wwww + 1) isSurrogate = true; int b2 = getNextUtf8Byte(i++, count); int b3 = getNextUtf8Byte(i++, count); int b4 = getNextUtf8Byte(i++, count); readBuffer[j++] = (char)(0xd800 | ((((b1 & 0x07) << 2) | ((b2 & 0x30) >> 4) - 1) << 6) | ((b2 & 0x0f) << 2) | ((b3 & 0x30) >> 4)); readBuffer[j++] = (char)(0xdc | ((b3 & 0x0f) << 6) | b4); // TODO: test that surrogate value is legal. } else { // Otherwise, the 8th bit may not be set in UTF-8 encodingError("bad start for UTF-8 multi-byte sequence", b1, i); } if (readBuffer[j-1] == '\r') { sawCR = true; } } // How many characters have we read? readBufferLength = j; } /** * Return the next byte value in a UTF-8 sequence. * If it is not possible to get a byte from the current * entity, throw an exception. * @param pos The current position in the rawReadBuffer. * @param count The number of bytes in the rawReadBuffer * @return The significant six bits of a non-initial byte in * a UTF-8 sequence. * @exception EOFException If the sequence is incomplete. */ int getNextUtf8Byte (int pos, int count) throws java.lang.Exception { int val; // Take a character from the buffer // or from the actual input stream. if (pos < count) { val = rawReadBuffer[pos]; } else { val = is.read(); if (val == -1) { encodingError("unfinished multi-byte UTF-8 sequence at EOF", -1, pos); } } // Check for the correct bits at the // start. if ((val & 0xc0) != 0x80) { encodingError("bad continuation of multi-byte UTF-8 sequence", val, pos + 1); } // Return the significant bits. return (val & 0x3f); } /** * Convert a buffer of ISO-8859-1-encoded bytes into UTF-16 characters. *

When readDataChunk() calls this method, the raw bytes are in * rawReadBuffer, and the final characters will appear in * readBuffer. *

This is a direct conversion, with no tricks. * @param count The number of bytes to convert. * @see #readDataChunk * @see #rawReadBuffer * @see #readBuffer */ void copyIso8859_1ReadBuffer (int count) { int i, j; for (i = 0, j = readBufferPos; i < count; i++, j++) { readBuffer[j] = (char)(rawReadBuffer[i] & 0xff); if (readBuffer[j] == '\r') { sawCR = true; } } readBufferLength = j; } /** * Convert a buffer of UCS-2-encoded bytes into UTF-16 characters. *

When readDataChunk() calls this method, the raw bytes are in * rawReadBuffer, and the final characters will appear in * readBuffer. * @param count The number of bytes to convert. * @param shift1 The number of bits to shift byte 1. * @param shift2 The number of bits to shift byte 2 * @see #readDataChunk * @see #rawReadBuffer * @see #readBuffer */ void copyUcs2ReadBuffer (int count, int shift1, int shift2) throws java.lang.Exception { int j = readBufferPos; if (count > 0 && (count % 2) != 0) { encodingError("odd number of bytes in UCS-2 encoding", -1, count); } for (int i = 0; i < count; i+=2) { readBuffer[j++] = (char)(((rawReadBuffer[i] & 0xff) << shift1) | ((rawReadBuffer[i+1] & 0xff) << shift2)); if (readBuffer[j-1] == '\r') { sawCR = true; } } readBufferLength = j; } /** * Convert a buffer of UCS-4-encoded bytes into UTF-16 characters. *

When readDataChunk() calls this method, the raw bytes are in * rawReadBuffer, and the final characters will appear in * readBuffer. *

Java has 16-bit chars, but this routine will attempt to use * surrogates to encoding values between 0x00010000 and 0x000fffff. * @param count The number of bytes to convert. * @param shift1 The number of bits to shift byte 1. * @param shift2 The number of bits to shift byte 2 * @param shift3 The number of bits to shift byte 2 * @param shift4 The number of bits to shift byte 2 * @see #readDataChunk * @see #rawReadBuffer * @see #readBuffer */ void copyUcs4ReadBuffer (int count, int shift1, int shift2, int shift3, int shift4) throws java.lang.Exception { int j = readBufferPos; int value; if (count > 0 && (count % 4) != 0) { encodingError("number of bytes in UCS-4 encoding not divisible by 4", -1, count); } for (int i = 0; i < count; i+=4) { value = (((rawReadBuffer[i] & 0xff) << shift1) | ((rawReadBuffer[i+1] & 0xff) << shift2) | ((rawReadBuffer[i+2] & 0xff) << shift3) | ((rawReadBuffer[i+3] & 0xff) << shift4)); if (value < 0x0000ffff) { readBuffer[j++] = (char)value; if (value == (int)'\r') { sawCR = true; } } else if (value < 0x000fffff) { readBuffer[j++] = (char)(0xd8 | ((value & 0x000ffc00) >> 10)); readBuffer[j++] = (char)(0xdc | (value & 0x0003ff)); } else { encodingError("value cannot be represented in UTF-16", value, i); } } readBufferLength = j; } /** * Report a character encoding error. */ void encodingError (String message, int value, int offset) throws java.lang.Exception { String uri; if (value >= 0) { message = message + " (byte value: 0x" + Integer.toHexString(value) + ')'; } if (externalEntity != null) { uri = externalEntity.getURL().toString(); } else { uri = baseURI; } handler.error(message, uri, -1, offset + currentByteCount); }  ////////////////////////////////////////////////////////////////////// // Local Variables. ////////////////////////////////////////////////////////////////////// /** * Re-initialize the variables for each parse. */ void initializeVariables () { // No errors; first line errorCount = 0; line = 1; column = 0; // Set up the buffers for data and names dataBufferPos = 0; dataBuffer = new char[DATA_BUFFER_INITIAL]; nameBufferPos = 0; nameBuffer = new char[NAME_BUFFER_INITIAL]; // Set up the DTD hash tables elementInfo = new Hashtable(); entityInfo = new Hashtable(); notationInfo = new Hashtable(); // Set up the variables for the current // element context. currentElement = null; currentElementContent = CONTENT_UNDECLARED; // Set up the input variables sourceType = INPUT_NONE; inputStack = new Stack(); entityStack = new Stack(); externalEntity = null; tagAttributePos = 0; tagAttributes = new String[100]; rawReadBuffer = new byte[READ_BUFFER_MAX]; readBufferOverflow = -1; context = CONTEXT_NONE; symbolTable = new Object[SYMBOL_TABLE_LENGTH]; } /** * Clean up after the parse to allow some garbage collection. * Leave around anything that might be useful for queries. */ void cleanupVariables () { errorCount = -1; line = -1; column = -1; dataBuffer = null; nameBuffer = null; currentElement = null; currentElementContent = CONTENT_UNDECLARED; sourceType = INPUT_NONE; inputStack = null; externalEntity = null; entityStack = null; } // // The current XML handler interface. // XmlHandler handler; // // I/O information. // private Reader reader; // current reader private InputStream is; // current input stream private int line; // current line number private int column; // current column number private int sourceType; // type of input source private Stack inputStack; // stack of input soruces private URLConnection externalEntity; // current external entity private int encoding; // current character encoding. private int currentByteCount; // how many bytes read from current source. // // Maintain a count of errors. // private int errorCount; // // Buffers for decoded but unparsed character input. // private final static int READ_BUFFER_MAX = 16384; private char readBuffer[]; private int readBufferPos; private int readBufferLength; private int readBufferOverflow; // overflow character from last data chunk. // // Buffer for undecoded raw byte input. // private byte rawReadBuffer[]; // // Buffer for parsed character data. // private static int DATA_BUFFER_INITIAL = 4096; private char dataBuffer[]; private int dataBufferPos; // // Buffer for parsed names. // private static int NAME_BUFFER_INITIAL = 1024; private char nameBuffer[]; private int nameBufferPos; // // Hashtables for DTD information on elements, entities, and notations. // private Hashtable elementInfo; private Hashtable entityInfo; private Hashtable notationInfo; // // Element type currently in force. // private String currentElement; private int currentElementContent; // // Base external identifiers for resolution. // private String basePublicId; private String baseURI; private int baseEncoding; private Reader baseReader; private InputStream baseInputStream; private char baseInputBuffer[]; private int baseInputBufferStart; private int baseInputBufferLength; // // Stack of entity names, to help detect recursion. // private Stack entityStack; // // Are we in a context where PEs are allowed? // private int context; // // Symbol table, for internalising names. // private Object symbolTable[]; private final static int SYMBOL_TABLE_LENGTH = 1087; // // Hash table of attributes found in current start tag. // private String tagAttributes[]; private int tagAttributePos; // // Utility flag: have we noticed a CR while reading the last // data chunk? If so, we will have to go back and normalise // CR/LF. // private boolean sawCR; }