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Jython is an implementation of the high-level, dynamic, object-oriented
language Python written in 100% Pure Java, and seamlessly integrated with
the Java platform. It thus allows you to run Python on any Java platform.
/* Copyright (c) 2007 Jython Developers */
package org.python.core.io;
import java.nio.ByteBuffer;
import java.util.EnumSet;
import org.python.core.Py;
import org.python.core.PyObject;
import org.python.core.PyString;
import org.python.core.PyTuple;
/**
* A Buffered text stream in universal newlines mode.
*
* @author Philip Jenvey
*/
public class UniversalIOWrapper extends TextIOBase {
/** Whether the next character, if it's an LF, should be skipped
* (the previous character was a CR) */
private boolean skipNextLF = false;
/** The Newlines encountered in this file */
private EnumSet newlineTypes = EnumSet.noneOf(Newline.class);
/**
* Contruct a UniversalIOWrapper wrapping the given
* BufferedIOBase.
*
* @param bufferedIO {@inheritDoc}
*/
public UniversalIOWrapper(BufferedIOBase bufferedIO) {
super(bufferedIO);
}
@Override
public String read(int size) {
if (size < 0) {
return readall();
}
// Avoid ByteBuffer (this.readahead) method calls in the inner
// loop by reading directly from the readahead's backing array
byte[] readaheadArray;
int readaheadPos;
char[] builderArray = new char[size];
int builderPos = 0;
do {
readaheadArray = readahead.array();
readaheadPos = readahead.position();
while (readaheadPos < readahead.limit() && builderPos < size) {
char next = (char)(readaheadArray[readaheadPos++] & 0xff);
switch (next) {
case '\r':
next = '\n';
// Don't skipNextLF (identify CR immediately) at
// EOF
if (readaheadPos == readahead.limit()) {
if (readChunk() == 0) {
// EOF
newlineTypes.add(Newline.CR);
builderArray[builderPos++] = next;
return new String(builderArray, 0, builderPos);
}
// Not EOF and readChunk replaced the
// readahead; reset the readahead info
readaheadArray = readahead.array();
readaheadPos = readahead.position();
}
skipNextLF = true;
break;
case '\n':
if (skipNextLF) {
skipNextLF = false;
newlineTypes.add(Newline.CRLF);
continue;
}
newlineTypes.add(Newline.LF);
break;
default:
if (skipNextLF) {
skipNextLF = false;
newlineTypes.add(Newline.CR);
}
}
builderArray[builderPos++] = next;
}
} while (builderPos < size && readChunk(size - builderPos) > 0);
// Finally reposition the readahead to where we ended. The
// position is invalid if the readahead is empty (at EOF;
// readChunk() returned 0)
if (readahead.hasRemaining()) {
readahead.position(readaheadPos);
}
// Shrink the readahead if it grew
packReadahead();
return new String(builderArray, 0, builderPos);
}
@Override
public String readall() {
// Read the remainder of file
ByteBuffer remaining = bufferedIO.readall();
// Create an array that accommodates the readahead and the
// remainder
char[] all = new char[readahead.remaining() + remaining.remaining()];
// Consume the readahead
int length = readLoop(readahead.array(), readahead.position(), all, 0,
readahead.remaining());
readahead.position(readahead.limit());
// Consume the remainder of the file
length += readLoop(remaining.array(), remaining.position(), all, length,
remaining.remaining());
// Handle skipNextLF at EOF
if (skipNextLF) {
skipNextLF = false;
newlineTypes.add(Newline.CR);
}
return new String(all, 0, length);
}
/**
* Read and convert the src byte array into the dest char array.
*
* Converts CR and CRLF to LF. No attempt is made to handle CRLF
* at EOF; skipNextLF may be toggled true after this method
* returns.
*
* @param src the source byte array
* @param srcPos starting position in the source array
* @param dest the destination char array
* @param destPos starting position in the destination array
* @param length the number of array elements to be copied
* @return the number of chars written to the destination array
*/
private int readLoop(byte[] src, int srcPos, char[] dest, int destPos, int length) {
int destStartPos = destPos;
int srcEndPos = srcPos + length;
while (srcPos < srcEndPos) {
char next = (char)(src[srcPos++] & 0xff);
switch (next) {
case '\r':
next = '\n';
skipNextLF = true;
break;
case '\n':
if (skipNextLF) {
skipNextLF = false;
newlineTypes.add(Newline.CRLF);
continue;
}
newlineTypes.add(Newline.LF);
break;
default:
if (skipNextLF) {
skipNextLF = false;
newlineTypes.add(Newline.CR);
}
}
dest[destPos++] = next;
}
return destPos - destStartPos;
}
@Override
public String readline(int size) {
// Avoid ByteBuffer (this.readahead) and StringBuilder
// (this.builder) method calls in the inner loop by reading
// directly from the readahead's backing array and writing to
// an interim char array (this.interimBuilder)
byte[] readaheadArray;
int readaheadPos;
int interimBuilderPos;
do {
readaheadArray = readahead.array();
readaheadPos = readahead.position();
interimBuilderPos = 0;
while (readaheadPos < readahead.limit() &&
(size < 0 || builder.length() + interimBuilderPos < size)) {
char next = (char)(readaheadArray[readaheadPos++] & 0xff);
switch (next) {
case '\r':
next = '\n';
// Don't skipNextLF (identify CR immediately) at
// EOF
if (readaheadPos == readahead.limit()) {
if (readChunk() == 0) {
// EOF
newlineTypes.add(Newline.CR);
interimBuilder[interimBuilderPos++] = next;
builder.append(interimBuilder, 0, interimBuilderPos);
// The readahead position is already valid
// (it's at 0)
return drainBuilder();
}
// Not EOF and readChunk replaced the
// readahead; reset the readahead info
readaheadPos = readahead.position();
}
skipNextLF = true;
interimBuilder[interimBuilderPos++] = next;
builder.append(interimBuilder, 0, interimBuilderPos);
// Reposition the readahead to where we ended
readahead.position(readaheadPos);
return drainBuilder();
case '\n':
if (skipNextLF) {
skipNextLF = false;
newlineTypes.add(Newline.CRLF);
continue;
}
newlineTypes.add(Newline.LF);
interimBuilder[interimBuilderPos++] = next;
builder.append(interimBuilder, 0, interimBuilderPos);
// Reposition the readahead to where we ended
readahead.position(readaheadPos);
return drainBuilder();
default:
if (skipNextLF) {
skipNextLF = false;
newlineTypes.add(Newline.CR);
}
}
interimBuilder[interimBuilderPos++] = next;
}
builder.append(interimBuilder, 0, interimBuilderPos);
} while ((size < 0 || builder.length() < size) && readChunk() > 0);
// Finally reposition the readahead to where we ended. The
// position is invalid if the readahead is empty (at EOF;
// readChunk() returned 0)
if (readahead.hasRemaining()) {
readahead.position(readaheadPos);
}
return drainBuilder();
}
@Override
public int write(String buf) {
// Universal newlines doesn't support writing; just raise the
// appropriate exception
checkClosed();
checkWritable();
return -1;
}
@Override
public long seek(long pos, int whence) {
pos = super.seek(pos, whence);
skipNextLF = false;
return pos;
}
@Override
public long tell() {
long pos = super.tell();
if (skipNextLF) {
// Look for a succeeding LF; if it exists, consume it and
// report the position as the beginning of the next
// newline
if (!atEOF()) {
int readaheadPos = readahead.position();
if (readahead.get(readaheadPos) == LF_BYTE) {
skipNextLF = false;
newlineTypes.add(Newline.CRLF);
readahead.position(++readaheadPos);
pos++;
}
}
}
return pos;
}
@Override
public PyObject getNewlines() {
int size = newlineTypes.size();
if (size == 0) {
return Py.None;
} else if (size == 1) {
Newline newline = newlineTypes.iterator().next();
return new PyString(newline.getValue());
}
PyObject[] newlines = new PyObject[size];
int i = 0;
for (Newline newline : newlineTypes) {
newlines[i++] = new PyString(newline.getValue());
}
return new PyTuple(newlines);
}
/**
* Newline types.
*
*/
private enum Newline {
/** Carriage return */
CR("\r"),
/** Line feed */
LF("\n"),
/** Carriage return line feed **/
CRLF("\r\n");
/** The String value */
private final String value;
/**
* Return the String value of this newline
*
* @return the newline character as a String
*/
public String getValue() { return value; }
/**
* Construct a new Newline.
*
* @param value the newline character as a String
*/
Newline(String value) {
this.value = value;
}
}
}