You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

286 lines
9.7 KiB

/*
* [The "BSD licence"]
* Copyright (c) 2005-2008 Terence Parr
* All rights reserved.
*
* Conversion to C#:
* Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
* 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.
*/
namespace Antlr.Runtime {
using System.Collections.Generic;
using ArgumentException = System.ArgumentException;
using ArgumentOutOfRangeException = System.ArgumentOutOfRangeException;
using ArgumentNullException = System.ArgumentNullException;
/** <summary>
* A pretty quick CharStream that pulls all data from an array
* directly. Every method call counts in the lexer. Java's
* strings aren't very good so I'm avoiding.
* </summary>
*/
[System.Serializable]
public class ANTLRStringStream : ICharStream {
/** <summary>The data being scanned</summary> */
protected char[] data;
/** <summary>How many characters are actually in the buffer</summary> */
protected int n;
/** <summary>0..n-1 index into string of next char</summary> */
protected int p = 0;
/** <summary>line number 1..n within the input</summary> */
int line = 1;
/** <summary>The index of the character relative to the beginning of the line 0..n-1</summary> */
int charPositionInLine = 0;
/** <summary>tracks how deep mark() calls are nested</summary> */
protected int markDepth = 0;
/** <summary>
* A list of CharStreamState objects that tracks the stream state
* values line, charPositionInLine, and p that can change as you
* move through the input stream. Indexed from 1..markDepth.
* A null is kept @ index 0. Create upon first call to mark().
* </summary>
*/
protected IList<CharStreamState> markers;
/** <summary>Track the last mark() call result value for use in rewind().</summary> */
protected int lastMarker;
/** <summary>What is name or source of this char stream?</summary> */
public string name;
/** <summary>Copy data in string to a local char array</summary> */
public ANTLRStringStream(string input)
: this(input, null) {
}
public ANTLRStringStream(string input, string sourceName)
: this(input.ToCharArray(), input.Length, sourceName) {
}
/** <summary>This is the preferred constructor as no data is copied</summary> */
public ANTLRStringStream(char[] data, int numberOfActualCharsInArray)
: this(data, numberOfActualCharsInArray, null) {
}
public ANTLRStringStream(char[] data, int numberOfActualCharsInArray, string sourceName) {
if (data == null)
throw new ArgumentNullException("data");
if (numberOfActualCharsInArray < 0)
throw new ArgumentOutOfRangeException();
if (numberOfActualCharsInArray > data.Length)
throw new ArgumentException();
this.data = data;
this.n = numberOfActualCharsInArray;
this.name = sourceName;
}
protected ANTLRStringStream() {
this.data = new char[0];
}
/** <summary>
* 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).
* </summary>
*/
public virtual int Index {
get {
return p;
}
}
public virtual int Line {
get {
return line;
}
set {
line = value;
}
}
public virtual int CharPositionInLine {
get {
return charPositionInLine;
}
set {
charPositionInLine = value;
}
}
/** <summary>
* 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.
* </summary>
*/
public virtual void Reset() {
p = 0;
line = 1;
charPositionInLine = 0;
markDepth = 0;
}
public virtual void Consume() {
//System.out.println("prev p="+p+", c="+(char)data[p]);
if (p < n) {
charPositionInLine++;
if (data[p] == '\n') {
/*
System.out.println("newline char found on line: "+line+
"@ pos="+charPositionInLine);
*/
line++;
charPositionInLine = 0;
}
p++;
//System.out.println("p moves to "+p+" (c='"+(char)data[p]+"')");
}
}
public virtual 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 CharStreamConstants.EndOfFile; // invalid; no char before first char
}
}
if ((p + i - 1) >= n) {
//System.out.println("char LA("+i+")=EOF; p="+p);
return CharStreamConstants.EndOfFile;
}
//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 virtual int LT(int i) {
return LA(i);
}
public virtual int Count {
get {
return n;
}
}
public virtual int Mark() {
if (markers == null) {
markers = new List<CharStreamState>();
markers.Add(null); // depth 0 means no backtracking, leave blank
}
markDepth++;
CharStreamState state = null;
if (markDepth >= markers.Count) {
state = new CharStreamState();
markers.Add(state);
} else {
state = markers[markDepth];
}
state.p = p;
state.line = line;
state.charPositionInLine = charPositionInLine;
lastMarker = markDepth;
return markDepth;
}
public virtual void Rewind(int m) {
if (m < 0)
throw new ArgumentOutOfRangeException();
//if (m > markDepth)
// throw new ArgumentException();
CharStreamState state = markers[m];
// restore stream state
Seek(state.p);
line = state.line;
charPositionInLine = state.charPositionInLine;
Release(m);
}
public virtual void Rewind() {
Rewind(lastMarker);
}
public virtual void Release(int marker) {
// unwind any other markers made after m and release m
markDepth = marker;
// release this marker
markDepth--;
}
/** <summary>
* consume() ahead until p==index; can't just set p=index as we must
* update line and charPositionInLine.
* </summary>
*/
public virtual 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 < index) {
Consume();
}
}
public virtual string Substring(int start, int length) {
if (start < 0)
throw new ArgumentOutOfRangeException();
if (length < 0)
throw new ArgumentOutOfRangeException();
if (start + length > data.Length)
throw new ArgumentException();
if (length == 0)
return string.Empty;
return new string(data, start, length);
}
public virtual string SourceName {
get {
return name;
}
}
public override string ToString() {
return new string(data);
}
}
}