org.antlr.v4.runtime.ANTLRInputStream Maven / Gradle / Ivy
/*
* [The "BSD license"]
* Copyright (c) 2012 Terence Parr
* Copyright (c) 2012 Sam Harwell
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.antlr.v4.runtime;
import org.antlr.v4.runtime.misc.Interval;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.Arrays;
/** Vacuum all input from a Reader/InputStream and then treat it like a char[] buffer.
* Can also pass in a string or char[] to use.
*
* If you need encoding, pass in stream/reader with correct encoding.
*/
public class ANTLRInputStream implements CharStream {
public static final int READ_BUFFER_SIZE = 1024;
public static final int INITIAL_BUFFER_SIZE = 1024;
/** The data being scanned */
protected char[] data;
/** How many characters are actually in the buffer */
protected int n;
/** 0..n-1 index into string of next char */
protected int p=0;
/** What is name or source of this char stream? */
public String name;
public ANTLRInputStream() { }
/** Copy data in string to a local char array */
public ANTLRInputStream(String input) {
this.data = input.toCharArray();
this.n = input.length();
}
/** This is the preferred constructor for strings as no data is copied */
public ANTLRInputStream(char[] data, int numberOfActualCharsInArray) {
this.data = data;
this.n = numberOfActualCharsInArray;
}
public ANTLRInputStream(Reader r) throws IOException {
this(r, INITIAL_BUFFER_SIZE, READ_BUFFER_SIZE);
}
public ANTLRInputStream(Reader r, int initialSize) throws IOException {
this(r, initialSize, READ_BUFFER_SIZE);
}
public ANTLRInputStream(Reader r, int initialSize, int readChunkSize) throws IOException {
load(r, initialSize, readChunkSize);
}
public ANTLRInputStream(InputStream input) throws IOException {
this(new InputStreamReader(input), INITIAL_BUFFER_SIZE);
}
public ANTLRInputStream(InputStream input, int initialSize) throws IOException {
this(new InputStreamReader(input), initialSize);
}
public ANTLRInputStream(InputStream input, int initialSize, int readChunkSize) throws IOException {
this(new InputStreamReader(input), initialSize, readChunkSize);
}
public void load(Reader r, int size, int readChunkSize)
throws IOException
{
if ( r==null ) {
return;
}
if ( size<=0 ) {
size = INITIAL_BUFFER_SIZE;
}
if ( readChunkSize<=0 ) {
readChunkSize = READ_BUFFER_SIZE;
}
// System.out.println("load "+size+" in chunks of "+readChunkSize);
try {
// alloc initial buffer size.
data = new char[size];
// read all the data in chunks of readChunkSize
int numRead=0;
int p = 0;
do {
if ( p+readChunkSize > data.length ) { // overflow?
// System.out.println("### overflow p="+p+", data.length="+data.length);
data = Arrays.copyOf(data, data.length * 2);
}
numRead = r.read(data, p, readChunkSize);
// System.out.println("read "+numRead+" chars; p was "+p+" is now "+(p+numRead));
p += numRead;
} while (numRead!=-1); // while not EOF
// set the actual size of the data available;
// EOF subtracted one above in p+=numRead; add one back
n = p+1;
//System.out.println("n="+n);
}
finally {
r.close();
}
}
/** Reset the stream so that it's in the same state it was
* when the object was created *except* the data array is not
* touched.
*/
public void reset() {
p = 0;
}
@Override
public void consume() {
if (p >= n) {
assert LA(1) == IntStream.EOF;
throw new IllegalStateException("cannot consume EOF");
}
//System.out.println("prev p="+p+", c="+(char)data[p]);
if ( p < n ) {
p++;
//System.out.println("p moves to "+p+" (c='"+(char)data[p]+"')");
}
}
@Override
public int LA(int i) {
if ( i==0 ) {
return 0; // undefined
}
if ( i<0 ) {
i++; // e.g., translate LA(-1) to use offset i=0; then data[p+0-1]
if ( (p+i-1) < 0 ) {
return IntStream.EOF; // invalid; no char before first char
}
}
if ( (p+i-1) >= n ) {
//System.out.println("char LA("+i+")=EOF; p="+p);
return IntStream.EOF;
}
//System.out.println("char LA("+i+")="+(char)data[p+i-1]+"; p="+p);
//System.out.println("LA("+i+"); p="+p+" n="+n+" data.length="+data.length);
return data[p+i-1];
}
public int LT(int i) {
return LA(i);
}
/** Return the current input symbol index 0..n where n indicates the
* last symbol has been read. The index is the index of char to
* be returned from LA(1).
*/
@Override
public int index() {
return p;
}
@Override
public int size() {
return n;
}
/** mark/release do nothing; we have entire buffer */
@Override
public int mark() {
return -1;
}
@Override
public void release(int marker) {
}
/** consume() ahead until p==index; can't just set p=index as we must
* update line and charPositionInLine. If we seek backwards, just set p
*/
@Override
public void seek(int index) {
if ( index<=p ) {
p = index; // just jump; don't update stream state (line, ...)
return;
}
// seek forward, consume until p hits index
while ( p= n ) stop = n-1;
int count = stop - start + 1;
if ( start >= n ) return "";
// System.err.println("data: "+Arrays.toString(data)+", n="+n+
// ", start="+start+
// ", stop="+stop);
return new String(data, start, count);
}
@Override
public String getSourceName() {
return name;
}
@Override
public String toString() { return new String(data); }
}
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