123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186 |
- /*
- * Copyright 1999-2004 The Apache Software Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
- /* $Id$ */
-
- package org.apache.fop.util;
-
- import java.io.FilterOutputStream;
- import java.io.OutputStream;
- import java.io.IOException;
-
-
- /**
- * This class applies a RunLengthEncode filter to the stream.
- *
- * @author <a href="mailto:smwolke@geistig.com">Stephen Wolke</a>
- * @version $Id$
- */
- public class RunLengthEncodeOutputStream extends FilterOutputStream
- implements Finalizable {
-
- private static final int MAX_SEQUENCE_COUNT = 127;
- private static final int END_OF_DATA = 128;
- private static final int BYTE_MAX = 256;
-
- private static final int NOT_IDENTIFY_SEQUENCE = 0;
- private static final int START_SEQUENCE = 1;
- private static final int IN_SEQUENCE = 2;
- private static final int NOT_IN_SEQUENCE = 3;
-
- private int runCount = 0;
- private int isSequence = NOT_IDENTIFY_SEQUENCE;
- private byte[] runBuffer = new byte[MAX_SEQUENCE_COUNT + 1];
-
-
- /** @see java.io.FilterOutputStream **/
- public RunLengthEncodeOutputStream(OutputStream out) {
- super(out);
- }
-
-
- /** @see java.io.FilterOutputStream **/
- public void write(byte b)
- throws java.io.IOException {
- runBuffer[runCount] = b;
-
- switch (runCount) {
- case 0:
- runCount = 0;
- isSequence = NOT_IDENTIFY_SEQUENCE;
- runCount++;
- break;
- case 1:
- if (runBuffer[runCount] != runBuffer[runCount - 1]) {
- isSequence = NOT_IN_SEQUENCE;
- }
- runCount++;
- break;
- case 2:
- if (runBuffer[runCount] != runBuffer[runCount - 1]) {
- isSequence = NOT_IN_SEQUENCE;
- } else {
- if (isSequence == NOT_IN_SEQUENCE) {
- isSequence = START_SEQUENCE;
- } else {
- isSequence = IN_SEQUENCE;
- }
- }
- runCount++;
- break;
- case MAX_SEQUENCE_COUNT:
- if (isSequence == IN_SEQUENCE) {
- out.write(BYTE_MAX - (MAX_SEQUENCE_COUNT - 1));
- out.write(runBuffer[runCount - 1]);
- runBuffer[0] = runBuffer[runCount];
- runCount = 1;
- } else {
- out.write(MAX_SEQUENCE_COUNT);
- out.write(runBuffer, 0, runCount + 1);
- runCount = 0;
- }
- isSequence = NOT_IDENTIFY_SEQUENCE;
- break;
- default:
- switch (isSequence) {
- case IN_SEQUENCE:
- if (runBuffer[runCount] != runBuffer[runCount - 1]) {
- out.write(BYTE_MAX - (runCount - 1));
- out.write(runBuffer[runCount - 1]);
- runBuffer[0] = runBuffer[runCount];
- runCount = 1;
- isSequence = NOT_IDENTIFY_SEQUENCE;
- break;
- }
- runCount++;
- break;
- case NOT_IN_SEQUENCE:
- if (runBuffer[runCount] == runBuffer[runCount - 1]) {
- isSequence = START_SEQUENCE;
- }
- runCount++;
- break;
- case START_SEQUENCE:
- if (runBuffer[runCount] == runBuffer[runCount - 1]) {
- out.write(runCount - 3);
- out.write(runBuffer, 0, runCount - 2);
- runBuffer[0] = runBuffer[runCount];
- runBuffer[1] = runBuffer[runCount];
- runBuffer[2] = runBuffer[runCount];
- runCount = 3;
- isSequence = IN_SEQUENCE;
- break;
- } else {
- isSequence = NOT_IN_SEQUENCE;
- runCount++;
- break;
- }
- }
- }
- }
-
-
- /** @see java.io.FilterOutputStream **/
- public void write(byte[] b)
- throws IOException {
-
- for (int i = 0; i < b.length; i++) {
- this.write(b[i]);
- }
- }
-
-
- /** @see java.io.FilterOutputStream **/
- public void write(byte[] b, int off, int len)
- throws IOException {
-
- for (int i = 0; i < len; i++) {
- this.write(b[off + i]);
- }
- }
-
-
- /** @see Finalizable **/
- public void finalizeStream()
- throws IOException {
- switch (isSequence) {
- case IN_SEQUENCE:
- out.write(BYTE_MAX - (runCount - 1));
- out.write(runBuffer[runCount - 1]);
- break;
- default:
- out.write(runCount - 1);
- out.write(runBuffer, 0, runCount);
- }
-
- out.write(END_OF_DATA);
-
- flush();
- if (out instanceof Finalizable) {
- ((Finalizable) out).finalizeStream();
- }
- }
-
-
- /** @see java.io.FilterOutputStream **/
- public void close()
- throws IOException {
- finalizeStream();
- super.close();
- }
-
- }
|