package org.osgeo.proj4j.io;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;
import java.util.ArrayList;
import java.util.List;
public class Proj4FileReader
{
public Proj4FileReader() {
super();
}
public String[] readParametersFromFile( String authorityCode, String name )
throws IOException
{
// TODO: read comment preceding CS string as CS description
// TODO: use simpler parser than StreamTokenizer for speed and flexibility
// TODO: parse CSes line-at-a-time (this allows preserving CS param string for later access)
String filename = "/nad/" + authorityCode.toLowerCase();
InputStream inStr = Proj4FileReader.class.getResourceAsStream( filename );
if (inStr == null) {
throw new IllegalStateException("Unable to access CRS file: " + filename);
}
BufferedReader reader = new BufferedReader( new InputStreamReader(inStr) );
String[] args;
try {
args = readFile(reader, name);
}
finally {
if (reader != null)
reader.close();
}
return args;
}
private StreamTokenizer createTokenizer(BufferedReader reader)
{
StreamTokenizer t = new StreamTokenizer( reader );
t.commentChar( '#' );
t.ordinaryChars( '0', '9' );
t.ordinaryChars( '.', '.' );
t.ordinaryChars( '-', '-' );
t.ordinaryChars( '+', '+' );
t.wordChars( '0', '9' );
t.wordChars( '\'', '\'' );
t.wordChars( '"', '"' );
t.wordChars( '_', '_' );
t.wordChars( '.', '.' );
t.wordChars( '-', '-' );
t.wordChars( '+', '+' );
t.wordChars( ',', ',' );
t.wordChars( '@', '@' );
return t;
}
private String[] readFile( BufferedReader reader, String name)
throws IOException
{
StreamTokenizer t = createTokenizer(reader);
t.nextToken();
while ( t.ttype == '<' ) {
t.nextToken();
if ( t.ttype != StreamTokenizer.TT_WORD )
throw new IOException( t.lineno()+": Word expected after '<'" );
String crsName = t.sval;
t.nextToken();
if ( t.ttype != '>' )
throw new IOException( t.lineno()+": '>' expected" );
t.nextToken();
List v = new ArrayList();
while ( t.ttype != '<' ) {
if ( t.ttype == '+' )
t.nextToken();
if ( t.ttype != StreamTokenizer.TT_WORD )
throw new IOException( t.lineno()+": Word expected after '+'" );
String key = t.sval;
t.nextToken();
// parse =arg, if any
if ( t.ttype == '=' ) {
t.nextToken();
//Removed check to allow for proj4 hack +nadgrids=@null
//if ( t.ttype != StreamTokenizer.TT_WORD )
// throw new IOException( t.lineno()+": Value expected after '='" );
String value = t.sval;
t.nextToken();
addParam(v, key, value);
}
else {
// add param with no value
addParam(v, key, null);
}
}
t.nextToken();
if ( t.ttype != '>' )
throw new IOException( t.lineno()+": '<>' expected" );
t.nextToken();
// found requested CRS?
if ( crsName.equals( name ) ) {
String[] args = (String[]) v.toArray( new String[0] );
return args;
}
}
return null;
}
private static void addParam(List v, String key, String value)
{
String plusKey = key;
if ( ! key.startsWith("+") )
plusKey = "+" + key;
if (value != null)
v.add( plusKey+"="+value );
else
v.add(plusKey);
}
/**
* Gets the list of PROJ.4 parameters which define
* the coordinate system specified by <tt>name</tt>.
*
* @param crsName the name of the coordinate system
* @return the PROJ.4 projection parameters which define the coordinate system
*/
public String[] getParameters(String crsName) {
try {
int p = crsName.indexOf(':');
if (p >= 0) {
String auth = crsName.substring(0, p);
String id = crsName.substring(p + 1);
return readParametersFromFile(auth, id);
}
}
catch (IOException e) {
e.printStackTrace();
}
return null;
}
}