What Is poi-scratchpad-5.2.3.jar?
What Is poi-scratchpad-5.2.3.jar?
✍: FYIcenter.com
poi-scratchpad-5.2.3.jar is one of the JAR files for Apache POI 5.2.3, which
provides an API for Microsoft document files of Word, Excel, PowerPoint, and Visio.
poi-scratchpad-5.2.3.jar provides support for older versions of Microsoft document files like Word 97, Excel 97, PowerPoint 97, etc.
poi-scratchpad-5.2.3.jar is distributed as part of the poi-bin-5.2.3-20220909.zip download file.
JAR File Size and Download Location:
JAR name: poi-scratchpad-5.2.3.jar Target JDK version: 9 Dependency: poi.jar File name: poi-scratchpad.jar, poi-scratchpad-5.2.3.jar File size: 1897121 bytes Release date: 09-09-2022 Download: Apache POI Website
Here are Java Source Code files for poi-scratchpad-5.2.3.jar:
⏎ org/apache/poi/hdgf/HDGFLZWCompressor.java
/* ====================================================================
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You 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.
==================================================================== */
package org.apache.poi.hdgf;
import static org.apache.poi.util.LZWDecompresser.DICT_MASK;
import static org.apache.poi.util.LZWDecompresser.DICT_SIZE;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* Helper class to handle the Visio compatible streaming LZW compression.
* Need our own class to handle keeping track of the code buffer, pending bytes to write out etc.
* <p>
* TODO Fix this, as it starts to go wrong on large streams
*/
/* package */ final class HDGFLZWCompressor {
// We use 12 bit codes:
// * 0-255 are real bytes
// * 256-4095 are the substring codes
// Java handily initialises our buffer / dictionary
// to all zeros
private final byte[] dict = new byte[DICT_SIZE];
// The next block of data to be written out, minus its mask byte
private final byte[] buffer = new byte[16];
// And how long it is
// (Un-compressed codes are 1 byte each, compressed codes are two)
private int bufferLen;
// The raw length of a code is limited to 4 bits + 2
private final byte[] rawCode = new byte[18];
// And how much we're using
private int rawCodeLen;
// How far through the input and output streams we are
private int posInp;
private int posOut;
// What the next mask byte to output will be
private int nextMask;
// And how many bits we've already set
private int maskBitsSet;
private final OutputStream res;
public HDGFLZWCompressor(OutputStream res) {
this.res = res;
}
/**
* Returns the last place that the bytes from rawCode are found
* at in the buffer, or -1 if they can't be found
*/
private int findRawCodeInBuffer() {
// Work our way through all the codes until we
// find the right one. Visio starts from the end
for (int i = rawCodeLen+1; i < DICT_SIZE; i++) {
int pos = (posInp - i) & DICT_MASK;
// in the example data it seems, that the compressor doesn't like to wrap beyond DICT_SIZE
// if (pos + rawCodeLen > DICT_SIZE) continue;
boolean matches = true;
for (int j = 0; j < rawCodeLen; j++) {
if (dict[(pos + j) & DICT_MASK] != rawCode[j]) {
// Doesn't fit, can't be a match
matches = false;
break;
}
}
// Was this position a match?
if (matches) {
return pos;
}
}
// Not found
return -1;
}
/**
* Output the compressed representation for the bytes
* found in rawCode
*/
private void outputCompressed() throws IOException {
// It's not worth compressing only 1 or two bytes, due to the overheads
// So if asked, just output uncompressed
if (rawCodeLen < 3) {
final int rcl = rawCodeLen;
for (int i = 0; i < rcl; i++) {
outputUncompressed(rawCode[i]);
}
return;
}
// Grab where the data lives
int codesAt = findRawCodeInBuffer();
codesAt = (codesAt-18) & DICT_MASK;
// Increment the mask bit count, we've done another code
maskBitsSet++;
// Add the length+code to the buffer
// (The position is the first 12 bits, the length is the last 4 bits)
int bp1 = (codesAt & 0xFF);
int bp2 = (rawCodeLen - 3) + ((codesAt - bp1) >>> 4);
buffer[bufferLen++] = (byte) bp1;
buffer[bufferLen++] = (byte) bp2;
assert(maskBitsSet <= 8);
// If we're now at 8 codes, output
if (maskBitsSet == 8) {
output8Codes();
}
rawCodeLen = 0;
}
/**
* Output the un-compressed byte
*/
private void outputUncompressed(byte b) throws IOException {
// Set the mask bit for us
nextMask += (1 << maskBitsSet);
maskBitsSet++;
// And add us to the buffer + dictionary
buffer[bufferLen++] = b;
// If we're now at 8 codes, output
if (maskBitsSet == 8) {
output8Codes();
}
rawCodeLen = 0;
}
/**
* We've got 8 code worth to write out, so
* output along with the header
*/
private void output8Codes() throws IOException {
// Output the mask and the data
res.write(nextMask);
res.write(buffer, 0, bufferLen);
posOut += 1 + bufferLen;
// Reset things
nextMask = 0;
maskBitsSet = 0;
bufferLen = 0;
}
/**
* Does the compression
*/
public void compress(InputStream src) throws IOException {
int dataI = -1;
while (true) {
if (dataI > -1) {
// copy the last read byte into the dictionary.
// the example data compressor used self references, so we don't wait for filling the dictionary
// until we know if it's a un-/compressed token.
dict[(posInp++) & DICT_MASK] = (byte)dataI;
}
// This is an unsigned byte read from the stream
// It needs to be unsigned, so that bit stuff works
dataI = src.read();
// If we've run out of data, output anything that's pending then finish
if (dataI == -1) {
if (rawCodeLen > 0) {
outputCompressed();
if (maskBitsSet > 0) {
output8Codes();
}
}
break;
}
// This is a byte as looked up in the dictionary
// It needs to be signed, as it'll get passed on to the output stream
byte dataB = (byte) dataI;
// Try adding this new byte onto rawCode, and see if all of that is still found
// in the buffer dictionary or not
rawCode[rawCodeLen++] = dataB;
int rawAt = findRawCodeInBuffer();
if (rawAt > -1) {
// If we found it and are now at 18 bytes, we need to output our pending code block
if (rawCodeLen == 18) {
outputCompressed();
}
// If we did find all of rawCode with our new byte added on,
// we can wait to see what happens with the next byte
continue;
}
// If we get here, then the rawCode + this byte weren't found in the dictionary
// If there was something in rawCode before, then that was
// found in the dictionary, so output that compressed
rawCodeLen--;
if (rawCodeLen > 0) {
// Output the old rawCode
outputCompressed();
// Can this byte start a new rawCode, or does it need outputting itself?
rawCode[0] = dataB;
rawCodeLen = 1;
if (findRawCodeInBuffer() > -1) {
// Fits in, wait for next byte
continue;
}
// Doesn't fit, output
outputUncompressed(dataB);
} else {
// Nothing in rawCode before, so this byte isn't in the buffer dictionary
// Output it un-compressed
outputUncompressed(dataB);
}
}
}
}
⏎ org/apache/poi/hdgf/HDGFLZWCompressor.java
Or download all of them as a single archive file:
File name: poi-scratchpad-5.2.3-src.zip File size: 1238744 bytes Release date: 2022-09-09 Download
⇒ What Is poi-examples-5.2.3.jar?
⇐ What Is poi-excelant-5.2.3.jar?
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