antlr/runtime/CSharp/Antlr4.Runtime/ANTLRInputStream.cs

327 lines
10 KiB
C#

/*
* [The "BSD license"]
* Copyright (c) 2013 Terence Parr
* Copyright (c) 2013 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.
*/
using System;
using System.IO;
using Antlr4.Runtime;
using Antlr4.Runtime.Misc;
using Sharpen;
namespace Antlr4.Runtime
{
/// <summary>
/// Vacuum all input from a
/// <see cref="System.IO.StreamReader">System.IO.StreamReader</see>
/// /
/// <see cref="System.IO.Stream">System.IO.Stream</see>
/// and then treat it
/// like a
/// <code>char[]</code>
/// buffer. Can also pass in a
/// <see cref="string">string</see>
/// or
/// <code>char[]</code>
/// to use.
/// <p/>
/// If you need encoding, pass in stream/reader with correct encoding.
/// </summary>
public class AntlrInputStream : ICharStream
{
public const int ReadBufferSize = 1024;
public const int InitialBufferSize = 1024;
/// <summary>The data being scanned</summary>
protected internal char[] data;
/// <summary>How many characters are actually in the buffer</summary>
protected internal int n;
/// <summary>0..n-1 index into string of next char</summary>
protected internal int p = 0;
/// <summary>What is name or source of this char stream?</summary>
public string name;
public AntlrInputStream()
{
}
/// <summary>Copy data in string to a local char array</summary>
public AntlrInputStream(string input)
{
this.data = input.ToCharArray();
this.n = input.Length;
}
/// <summary>This is the preferred constructor for strings as no data is copied</summary>
public AntlrInputStream(char[] data, int numberOfActualCharsInArray)
{
this.data = data;
this.n = numberOfActualCharsInArray;
}
/// <exception cref="System.IO.IOException"></exception>
public AntlrInputStream(StreamReader r) : this(r, InitialBufferSize, ReadBufferSize
)
{
}
/// <exception cref="System.IO.IOException"></exception>
public AntlrInputStream(StreamReader r, int initialSize) : this(r, initialSize, ReadBufferSize
)
{
}
/// <exception cref="System.IO.IOException"></exception>
public AntlrInputStream(StreamReader r, int initialSize, int readChunkSize)
{
Load(r, initialSize, readChunkSize);
}
/// <exception cref="System.IO.IOException"></exception>
public AntlrInputStream(Stream input) : this(new StreamReader(input), InitialBufferSize
)
{
}
/// <exception cref="System.IO.IOException"></exception>
public AntlrInputStream(Stream input, int initialSize) : this(new StreamReader(input
), initialSize)
{
}
/// <exception cref="System.IO.IOException"></exception>
public AntlrInputStream(Stream input, int initialSize, int readChunkSize) : this(
new StreamReader(input), initialSize, readChunkSize)
{
}
/// <exception cref="System.IO.IOException"></exception>
public virtual void Load(StreamReader r, int size, int readChunkSize)
{
if (r == null)
{
return;
}
if (size <= 0)
{
size = InitialBufferSize;
}
if (readChunkSize <= 0)
{
readChunkSize = ReadBufferSize;
}
// 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;
}
finally
{
//System.out.println("n="+n);
r.Close();
}
}
/// <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>
/// <remarks>
/// 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.
/// </remarks>
public virtual void Reset()
{
p = 0;
}
public virtual void Consume()
{
if (p >= n)
{
System.Diagnostics.Debug.Assert(La(1) == IntStreamConstants.Eof);
throw new InvalidOperationException("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]+"')");
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 IntStreamConstants.Eof;
}
}
// invalid; no char before first char
if ((p + i - 1) >= n)
{
//System.out.println("char LA("+i+")=EOF; p="+p);
return IntStreamConstants.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 virtual int Lt(int i)
{
return La(i);
}
/// <summary>
/// Return the current input symbol index 0..n where n indicates the
/// last symbol has been read.
/// </summary>
/// <remarks>
/// 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).
/// </remarks>
public virtual int Index
{
get
{
return p;
}
}
public virtual int Size
{
get
{
return n;
}
}
/// <summary>mark/release do nothing; we have entire buffer</summary>
public virtual int Mark()
{
return -1;
}
public virtual void Release(int marker)
{
}
/// <summary>
/// consume() ahead until p==index; can't just set p=index as we must
/// update line and charPositionInLine.
/// </summary>
/// <remarks>
/// 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
/// </remarks>
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 && index < n)
{
Consume();
}
}
public virtual string GetText(Interval interval)
{
int start = interval.a;
int stop = interval.b;
if (stop >= n)
{
stop = n - 1;
}
int count = stop - start + 1;
if (start >= n)
{
return string.Empty;
}
// System.err.println("data: "+Arrays.toString(data)+", n="+n+
// ", start="+start+
// ", stop="+stop);
return new string(data, start, count);
}
public virtual string SourceName
{
get
{
return name;
}
}
public override string ToString()
{
return new string(data);
}
}
}