readercharstream.java

Python Development Environment (Python IDE plugin for Eclipse). Features editor, code completion, re

package org.python.pydev.parser.jython;

/**
 * An implementation of interface CharStream, where the data is read from a Reader. This file started life as a copy of ASCII_CharStream.java.
 */

public final class ReaderCharStream implements CharStream {
	int bufsize;

	int available;

	int tokenBegin;

	public int bufpos = -1;

	private int bufline[];

	private int bufcolumn[];

	private int column = 0;

	private int line = 1;

	private boolean prevCharIsCR = false;

	private boolean prevCharIsLF = false;

	private java.io.Reader inputStream;

	private char[] buffer;

	private int maxNextCharInd = 0;

	private int inBuf = 0;
	
	private static final boolean DEBUG = false;

	private final void ExpandBuff(boolean wrapAround) {
		char[] newbuffer = new char[bufsize + 2048];
		int newbufline[] = new int[bufsize + 2048];
		int newbufcolumn[] = new int[bufsize + 2048];

		try {
			if (wrapAround) {
				System.arraycopy(buffer, tokenBegin, newbuffer, 0, bufsize - tokenBegin);
				System.arraycopy(buffer, 0, newbuffer, bufsize - tokenBegin, bufpos);
				buffer = newbuffer;

				System.arraycopy(bufline, tokenBegin, newbufline, 0, bufsize - tokenBegin);
				System.arraycopy(bufline, 0, newbufline, bufsize - tokenBegin, bufpos);
				bufline = newbufline;

				System.arraycopy(bufcolumn, tokenBegin, newbufcolumn, 0, bufsize - tokenBegin);
				System.arraycopy(bufcolumn, 0, newbufcolumn, bufsize - tokenBegin, bufpos);
				bufcolumn = newbufcolumn;

				maxNextCharInd = (bufpos += (bufsize - tokenBegin));
			} else {
				System.arraycopy(buffer, tokenBegin, newbuffer, 0, bufsize - tokenBegin);
				buffer = newbuffer;

				System.arraycopy(bufline, tokenBegin, newbufline, 0, bufsize - tokenBegin);
				bufline = newbufline;

				System.arraycopy(bufcolumn, tokenBegin, newbufcolumn, 0, bufsize - tokenBegin);
				bufcolumn = newbufcolumn;

				maxNextCharInd = (bufpos -= tokenBegin);
			}
		} catch (Throwable t) {
			throw new Error(t.getMessage());
		}

		bufsize += 2048;
		available = bufsize;
		tokenBegin = 0;
	}

	private final void FillBuff() throws java.io.IOException {
		if (maxNextCharInd == available) {
			if (available == bufsize) {
				if (tokenBegin > 2048) {
					bufpos = maxNextCharInd = 0;
					available = tokenBegin;
				} else if (tokenBegin < 0)
					bufpos = maxNextCharInd = 0;
				else
					ExpandBuff(false);
			} else if (available > tokenBegin)
				available = bufsize;
			else if ((tokenBegin - available) < 2048)
				ExpandBuff(true);
			else
				available = tokenBegin;
		}

		int i;
		try {
			if ((i = inputStream.read(buffer, maxNextCharInd, available - maxNextCharInd)) == -1) {
				inputStream.close();
				throw new java.io.IOException();
			} else
				maxNextCharInd += i;
			return;
		} catch (java.io.IOException e) {
			--bufpos;
			backup(0);
			if (tokenBegin == -1)
				tokenBegin = bufpos;
			throw e;
		}
	}

	public final char BeginToken() throws java.io.IOException {
		tokenBegin = -1;
		char c = readChar();
		tokenBegin = bufpos;

		if(DEBUG){
			System.out.println("ReaderCharStream: BeginToken >>"+(int)c+"<<");
		}
		return c;
	}

	private final void UpdateLineColumn(char c) {
		column++;

		if (prevCharIsLF) {
			prevCharIsLF = false;
			line += (column = 1);
		} else if (prevCharIsCR) {
			prevCharIsCR = false;
			if (c == '\n') {
				prevCharIsLF = true;
			} else
				line += (column = 1);
		}

		switch (c) {
		case '\r':
			prevCharIsCR = true;
			break;
		case '\n':
			prevCharIsLF = true;
			break;
		// ok, this was commented out because the position would not reflect correctly the positions found in the ast.
		// this may have other problems, but they have to be analyzed better to see the problems this may bring
		// (files that mix tabs and spaces may suffer, but I could not find out very well the problems -- anyway,
		// restricting the analysis to files that have only tabs or only spaces seems reasonable -- shortcuts are available
		// so that we can convert a file from one type to another, so, what remains is making some lint analysis to be sure of it).
		// case '\t' :
		// column--;
		// column += (8 - (column & 07));
		// break;
		default:
			break;
		}

		bufline[bufpos] = line;
		bufcolumn[bufpos] = column;
	}

	public final char readChar() throws java.io.IOException {
		if (inBuf > 0) {
			--inBuf;
			return buffer[(bufpos == bufsize - 1) ? (bufpos = 0) : ++bufpos];
		}

		if (++bufpos >= maxNextCharInd)
			FillBuff();

		char c = buffer[bufpos];

		UpdateLineColumn(c);
		if(DEBUG){
			System.out.println("ReaderCharStream: readChar >>"+(int)c+"<<");
		}
		return (c);
	}

	/**
	 * @deprecated
	 * @see #getEndColumn
	 */

	public final int getColumn() {
		return bufcolumn[bufpos];
	}

	/**
	 * @deprecated
	 * @see #getEndLine
	 */

	public final int getLine() {
		return bufline[bufpos];
	}

	public final int getEndColumn() {
		return bufcolumn[bufpos];
	}

	public final int getEndLine() {
		return bufline[bufpos];
	}

	public final int getBeginColumn() {
		return bufcolumn[tokenBegin];
	}

	public final int getBeginLine() {
		return bufline[tokenBegin];
	}

	public final void backup(int amount) {
		if(DEBUG){
			System.out.println("ReaderCharStream: backup >>"+amount+"<<");
		}

		inBuf += amount;
		if ((bufpos -= amount) < 0)
			bufpos += bufsize;
	}

	public ReaderCharStream(java.io.Reader dstream) {
		inputStream = dstream;
		line = 1;
		column = 0;

		available = bufsize = 4096;
		buffer = new char[bufsize];
		bufline = new int[bufsize];
		bufcolumn = new int[bufsize];
	}

	public final String GetImage() {
		String s = null;
		if (bufpos >= tokenBegin)
			s = new String(buffer, tokenBegin, bufpos - tokenBegin + 1);
		else
			s = new String(buffer, tokenBegin, bufsize - tokenBegin) + new String(buffer, 0, bufpos + 1);
		
		if(DEBUG){
			System.out.println("ReaderCharStream: GetImage >>"+s+"<<");
		}
		return s;
	}

	public final char[] GetSuffix(int len) {
		char[] ret = new char[len];

		if ((bufpos + 1) >= len)
			System.arraycopy(buffer, bufpos - len + 1, ret, 0, len);
		else {
			System.arraycopy(buffer, bufsize - (len - bufpos - 1), ret, 0, len - bufpos - 1);
			System.arraycopy(buffer, 0, ret, len - bufpos - 1, bufpos + 1);
		}
		if(DEBUG){
			System.out.println("ReaderCharStream: GetSuffix:"+len+" >>"+new String(ret)+"<<");
		}

		return ret;
	}

	public void Done() {
		buffer = null;
		bufline = null;
		bufcolumn = null;
	}

}