gecko-dev/grendel/calypso/util/ByteLineBuffer.java
1999-11-02 01:51:54 +00:00

350 lines
13 KiB
Java

/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil -*-
*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the Grendel mail/news client.
*
* The Initial Developer of the Original Code is Netscape Communications
* Corporation. Portions created by Netscape are
* Copyright (C) 1997 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*/
package calypso.util;
/**
* This class is stores data in a private ByteBuf appending new
* data as needed, and returning line separated data.
*/
public class ByteLineBuffer {
private static final boolean DEBUG = false;
private boolean buffer_full;
private ByteBuf buffer;
private ByteBuf outputeol;
private ByteBuf inputeol;
/**
* Constructs an empty ByteLineBuffer.
*/
public ByteLineBuffer() {
buffer = new ByteBuf();
buffer_full = false;
if (DEBUG) {
System.err.println("BLB " + hashCode() + ": created");
}
}
/**
* Appends data to the end of the internal ByteBuf.
* @param buf data to append to internal buffer
*/
public void pushBytes(ByteBuf buf) {
if (DEBUG) {
System.err.print("BLB " + hashCode() + ": pushBytes(\"");
byte b[] = buf.toBytes();
for (int i = 0; i < buf.length(); i++)
System.err.print((b[i] == '\r' ? "\\r" :
b[i] == '\n' ? "\\n" :
b[i] == '\t' ? "\\t" :
b[i] == '"' ? "\\\"" :
b[i] == '\\' ? "\\\\" :
new String(b, i, 1)));
System.err.print("\")\n");
}
buffer.append(buf);
}
/**
* indicates that the last piece of data is now present.
*/
public void pushEOF() {
if (DEBUG) {
System.err.println("BLB " + hashCode() + ": pushEOF()");
}
buffer_full = true;
}
/** Sets the EOL characters to look for in the incoming stream. Setting
* this to be null will cause it to look for any of <CR>, <LF>, or <CRLF>.
* Note that null (the default) could cause up to one extra to be held in
* the buffer (in the case where the last byte read from the underlying
* stream was <CR>, and no following byte (or EOF) has yet been read.)
*/
public void setInputEOL(ByteBuf buf) {
Assert.Assertion(buf == null || buf.length() > 0);
inputeol = buf;
}
/**
* End of line characters <CR> & <LF> or any combination
* will be replaced by this string if it is present. Setting
* this to a zero length string will cause them to be stripped.
* Setting this to null will cause the EOL characters to be passed
* through unchanged (the default).
* @param buf ByteBuf representing EOL replacement string
*/
public void setOutputEOL(ByteBuf buf) {
outputeol = buf;
}
/**
* Returns a ByteBuf with a line of data which was separated by
* <CR><LF> or any combination. Holds the last line in the ByteBuf
* until pushEOF() is called. If a ByteBuf containing data is sent in,
* the data is removed.
* @param buf single line of data in a ByteBuf
* @return true if a line was retrieved, false if not
*/
public boolean pullLine(ByteBuf buf) {
int position;
int buffer_length;
byte value;
// Remove any data that already exists in the buffer sent in
buf.setLength(0);
if (buffer_full && buffer == null)
return false;
buffer_length = buffer.length();
if (inputeol != null) {
int last = buffer_length - inputeol.length() + 1;
byte first = inputeol.byteAt(0);
byte[] peekbuf = buffer.toBytes();
for (position = 0 ; position < last ; position++) {
if (peekbuf[position] == first) {
boolean match = true;
for (int j=inputeol.length() - 1 ; j>=1 ; j--) {
if (peekbuf[position + j] != inputeol.byteAt(j)) {
match = false;
break;
}
}
if (match) {
buf.setLength(0);
if (outputeol != null) {
buf.append(peekbuf, 0, position);
buf.append(outputeol);
} else {
buf.append(peekbuf, 0,
position + inputeol.length());
}
buffer.remove(0, position + inputeol.length());
if (DEBUG) {
System.err.print("BLB " + hashCode() +
": EOL matched; returning: \"");
byte b[] = buf.toBytes();
for (int i = 0; i < buf.length(); i++)
System.err.print((b[i] == '\r' ? "\\r" :
b[i] == '\n' ? "\\n" :
b[i] == '\t' ? "\\t" :
b[i] == '"' ? "\\\"" :
b[i] == '\\' ? "\\\\" :
new String(b, i, 1)));
System.err.print("\"\n");
}
return true;
}
}
}
} else {
// process the entire buffer, or until a newline character is hit
for (position = 0; position < buffer_length; position++) {
value = buffer.byteAt(position);
if (value == '\n' || value == '\r') {
boolean ambiguous = true;
position++;
// got a newline, pass it
if (value == '\r' && position < buffer_length) {
if (DEBUG) {
System.err.println("BLB " + hashCode() +
": got \\r not at end of buffer");
}
// if we have seen \r, and we know what character
// lies after it, then there is no ambiguity:
// the linebreak is "\r" or "\r\n", and we can
// tell which it is.
//
ambiguous = false;
// if we are not replacing the EOL chars, return the
// existing ones
if (outputeol == null)
buf.append(value);
value = buffer.byteAt(position);
if (value == '\n') {
position++;
if (outputeol == null)
buf.append(value);
}
} else {
if (DEBUG) {
if (value == '\r')
System.err.println("BLB " + hashCode() +
": got \\r at end of buffer");
else
System.err.println("BLB " + hashCode() +
": got \\n without \\r");
}
// If we have seen \n, then the linebreak is
// unambiguously "\n". If we have seen \r, but we
// don't know what character follows it (because
// it happened to be at the end of the buffer) then
// the linebreak is ambiguous ("\r" or "\r\n").
//
ambiguous = (value == '\r');
if (outputeol == null) {
buf.append(value);
}
}
// if this is the last line in the buffer, and pushEOF()
// hasn't been called, and the linebreak was ambiguous,
// then wait for more data or a call to pushEOF() before
// returning this line.
//
if (position == buffer_length &&
!buffer_full &&
ambiguous) {
if (DEBUG) {
System.err.println("BLB " + hashCode() +
": waiting for next line");
}
return false;
}
// remove the string from the internal ByteBuf
buffer.remove(0,position);
// if we have a replacement EOL string, use it
if (outputeol != null)
buf.append(outputeol);
if (DEBUG) {
System.err.print("BLB " + hashCode() +
": returning line: \"");
byte b[] = buf.toBytes();
for (int i = 0; i < buf.length(); i++)
System.err.print((b[i] == '\r' ? "\\r" :
b[i] == '\n' ? "\\n" :
b[i] == '\t' ? "\\t" :
b[i] == '"' ? "\\\"" :
b[i] == '\\' ? "\\\\" :
new String(b, i, 1)));
System.err.print("\"\n");
}
return true;
}
else
// append bytes to output ByteBuf
buf.append(value);
}
}
// process full buffer
if (buffer_full && buffer_length > 0)
{
if (outputeol != null)
buf.append(outputeol);
buffer.remove(0,position);
buffer.Recycle(buffer);
buffer = null;
if (DEBUG) {
System.err.print("BLB " + hashCode() +
": at EOF; returning line: \"");
byte b[] = buf.toBytes();
for (int i = 0; i < buf.length(); i++)
System.err.print((b[i] == '\r' ? "\\r" :
b[i] == '\n' ? "\\n" :
b[i] == '\t' ? "\\t" :
b[i] == '"' ? "\\\"" :
b[i] == '\\' ? "\\\\" :
new String(b, i, 1)));
System.err.print("\"\n");
}
return true;
}
// didn't get a string this time around.
buf.setLength(0);
if (DEBUG) {
System.err.println("BLB " + hashCode() +
": don't have a line yet");
}
return false;
}
// public static void main(String args[]) {
//
// ByteLineBuffer blb = new ByteLineBuffer();
// ByteBuf bb = new ByteBuf();
// ByteBuf line_bytes = new ByteBuf(100);
//
// bb.setLength(0);
// bb.append("from: jwz");
// System.err.println("\npushed \"" + bb + "\""); blb.pushBytes(bb);
// while(blb.pullLine(line_bytes)) {
// System.err.println(" pulled \"" + line_bytes + "\"");
// }
//
// bb.setLength(0);
// bb.append("\r\n");
// System.err.println("\npushed \"" + bb + "\""); blb.pushBytes(bb);
// while(blb.pullLine(line_bytes)) {
// System.err.println(" pulled \"" + line_bytes + "\"");
// }
//
// bb.setLength(0);
// bb.append("content-type: text/plain");
// System.err.println("\npushed \"" + bb + "\""); blb.pushBytes(bb);
// while(blb.pullLine(line_bytes)) {
// System.err.println(" pulled \"" + line_bytes + "\"");
// }
//
// bb.setLength(0);
// bb.append("\r\n");
// System.err.println("\npushed \"" + bb + "\""); blb.pushBytes(bb);
// while(blb.pullLine(line_bytes)) {
// System.err.println(" pulled \"" + line_bytes + "\"");
// }
//
// bb.setLength(0);
// System.err.println("\npushed EOF"); blb.pushEOF();
// while(blb.pullLine(line_bytes)) {
// System.err.println(" pulled \"" + line_bytes + "\"");
// }
// }
}