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JSONzip

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This commit is contained in:
Douglas Crockford 2013-04-19 14:04:06 -07:00
parent 327e9a56fd
commit 0cdef7d816
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169
zip/BitInputStream.java Normal file
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package org.json.zip;
import java.io.IOException;
import java.io.InputStream;
/*
Copyright (c) 2013 JSON.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The Software shall be used for Good, not Evil.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
/**
* This is a big endian bit reader. It reads its bits from an InputStream.
*
* @version 2013-04-18
*
*/
public class BitInputStream implements BitReader {
/**
* 2^n - 1
*/
static final int[] mask = { 0, 1, 3, 7, 15, 31, 63, 127, 255 };
/**
* The number of bits remaining in the current byte.
*/
private int available = 0;
/**
* Up to a byte's worth of unread bits.
*/
private int unread = 0;
/**
* The source of the bits.
*/
private InputStream in;
/**
* The number of bits read so far. This is used in padding.
*/
private long nrBits = 0;
/**
* Make a BitReader from an InputStream. The BitReader will take bytes from
* the InputStream and unpack them into bits.
*
* @param in
* An InputStream.
*/
public BitInputStream(InputStream in) {
this.in = in;
}
/**
* Make a BitReader. The first byte is passed in explicitly, the remaining
* bytes are obtained from the InputStream. This makes it possible to look
* at the first byte of a stream before deciding that it should be read as
* bits.
*
* @param in
* An InputStream
* @param firstByte
* The first byte, which was probably read from in.
*/
public BitInputStream(InputStream in, int firstByte) {
this.in = in;
this.unread = firstByte;
this.available = 8;
}
/**
* Read one bit.
*
* @return true if it is a 1 bit.
*/
public boolean bit() throws IOException {
return read(1) != 0;
}
/**
* Get the number of bits that have been read from this BitInputStream.
* This includes pad bits that have been skipped, but might not include
* bytes that have been read from the underlying InputStream that have not
* yet been delivered as bits.
*
* @return The number of bits read so far.
*/
public long nrBits() {
return this.nrBits;
}
/**
* Check that the rest of the block has been padded with zeroes.
*
* @param factor
* The size of the block to pad. This will typically be 8, 16,
* 32, 64, 128, 256, etc.
* @return true if the block was zero padded, or false if the the padding
* contains any one bits.
* @throws IOException
*/
public boolean pad(int factor) throws IOException {
int padding = factor - (int) (this.nrBits % factor);
boolean result = true;
for (int i = 0; i < padding; i += 1) {
if (bit()) {
result = false;
}
}
return result;
}
/**
* Read some bits.
*
* @param width
* The number of bits to read. (0..32)
* @throws IOException
* @return the bits
*/
public int read(int width) throws IOException {
if (width == 0) {
return 0;
}
if (width < 0 || width > 32) {
throw new IOException("Bad read width.");
}
int result = 0;
while (width > 0) {
if (this.available == 0) {
this.unread = this.in.read();
if (this.unread < 0) {
throw new IOException("Attempt to read past end.");
}
this.available = 8;
}
int take = width;
if (take > this.available) {
take = this.available;
}
result |= ((this.unread >>> (this.available - take)) & mask[take])
<< (width - take);
this.nrBits += take;
this.available -= take;
width -= take;
}
return result;
}
}

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package org.json.zip;
import java.io.IOException;
import java.io.OutputStream;
/*
Copyright (c) 2013 JSON.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The Software shall be used for Good, not Evil.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
/**
* This is a big endian bit writer. It writes its bits to an OutputStream.
*
* @version 2013-04-18
*
*/
public class BitOutputStream implements BitWriter {
/**
* The number of bits written.
*/
private long nrBits = 0;
/**
* The destination of the bits.
*/
private OutputStream out;
/**
* Holder of bits not yet written.
*/
private int unwritten;
/**
* The number of unused bits in this.unwritten.
*/
private int vacant = 8;
/**
* Use an OutputStream to produce a BitWriter. The BitWriter will send its
* bits to the OutputStream as each byte is filled.
*
* @param out
* An Output Stream
*/
public BitOutputStream(OutputStream out) {
this.out = out;
}
/**
* Returns the number of bits that have been written to this
* bitOutputStream. This may include bits that have not yet been written
* to the underlying outputStream.
*/
public long nrBits() {
return this.nrBits;
}
/**
* Write a 1 bit.
*
* @throws IOException
*/
public void one() throws IOException {
write(1, 1);
}
/**
* Pad the rest of the block with zeroes and flush. pad(8) flushes the last
* unfinished byte. The underlying OutputStream will be flushed.
*
* @param factor
* The size of the block to pad. This will typically be 8, 16,
* 32, 64, 128, 256, etc.
* @return this
* @throws IOException
*/
public void pad(int factor) throws IOException {
int padding = factor - (int) (nrBits % factor);
int excess = padding & 7;
if (excess > 0) {
this.write(0, excess);
padding -= excess;
}
while (padding > 0) {
this.write(0, 8);
padding -= 8;
}
this.out.flush();
}
/**
* Write some bits. Up to 32 bits can be written at a time.
*
* @param bits
* The bits to be written.
* @param width
* The number of bits to write. (0..32)
* @throws IOException
*/
public void write(int bits, int width) throws IOException {
if (bits == 0 && width == 0) {
return;
}
if (width <= 0 || width > 32) {
throw new IOException("Bad write width.");
}
while (width > 0) {
int actual = width;
if (actual > this.vacant) {
actual = this.vacant;
}
this.unwritten |= ((bits >>> (width - actual)) &
BitInputStream.mask[actual]) << (this.vacant - actual);
width -= actual;
nrBits += actual;
this.vacant -= actual;
if (this.vacant == 0) {
this.out.write(this.unwritten);
this.unwritten = 0;
this.vacant = 8;
}
}
}
/**
* Write a 0 bit.
*
* @throws IOException
*/
public void zero() throws IOException {
write(0, 1);
}
}

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package org.json.zip;
import java.io.IOException;
public interface BitReader {
/**
* Read one bit.
*
* @return true if it is a 1 bit.
*/
public boolean bit() throws IOException;
/**
* Returns the number of bits that have been read from this bitreader.
*
* @return The number of bits read so far.
*/
public long nrBits();
/**
* Check that the rest of the block has been padded with zeroes.
*
* @param factor
* The size in bits of the block to pad. This will typically be
* 8, 16, 32, 64, 128, 256, etc.
* @return true if the block was zero padded, or false if the the padding
* contained any one bits.
* @throws IOException
*/
public boolean pad(int factor) throws IOException;
/**
* Read some bits.
*
* @param width
* The number of bits to read. (0..32)
* @throws IOException
* @return the bits
*/
public int read(int width) throws IOException;
}

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package org.json.zip;
import java.io.IOException;
/**
* A bitwriter is a an interface that allows for doing output at the bit level.
* Most IO interfaces only allow for writing at the byte level or higher.
*/
public interface BitWriter {
/**
* Returns the number of bits that have been written to this bitwriter.
*/
public long nrBits();
/**
* Write a 1 bit.
*
* @throws IOException
*/
public void one() throws IOException;
/**
* Pad the rest of the block with zeros and flush.
*
* @param factor
* The size in bits of the block to pad. This will typically be
* 8, 16, 32, 64, 128, 256, etc.
* @return true if the block was zero padded, or false if the the padding
* contains any one bits.
* @throws IOException
*/
public void pad(int factor) throws IOException;
/**
* Write some bits. Up to 32 bits can be written at a time.
*
* @param bits
* The bits to be written.
* @param width
* The number of bits to write. (0..32)
* @throws IOException
*/
public void write(int bits, int width) throws IOException;
/**
* Write a 0 bit.
*
* @throws IOException
*/
public void zero() throws IOException;
}

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package org.json.zip;
import java.io.IOException;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.Kim;
/*
Copyright (c) 2013 JSON.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The Software shall be used for Good, not Evil.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
/**
* JSONzip is a compression scheme for JSON text.
*
* @author JSON.org
* @version 2013-04-18
*/
/**
* A compressor implements the compression behavior of JSONzip. It provides a
* zip method that takes a JSONObject or JSONArray and delivers a stream of
* bits to a BitWriter.
*
* FOR EVALUATION PURPOSES ONLY. THIS PACKAGE HAS NOT BEEN TESTED ADEQUATELY
* FOR PRODUCTION USE.
*/
public class Compressor extends JSONzip {
/**
* A compressor outputs to a BitWriter.
*/
final BitWriter bitwriter;
/**
* Create a new compressor. It may be used for an entire session or
* subsession.
*
* @param bitwriter
* The BitWriter this Compressor will output to. Don't forget to
* flush.
*/
public Compressor(BitWriter bitwriter) {
super();
this.bitwriter = bitwriter;
}
/**
* Return a 4 bit code for a character in a JSON number. The digits '0' to
* '9' get the codes 0 to 9. '.' is 10, '-' is 11, '+' is 12, and 'E' or
* 'e' is 13.
*
* @param digit
* An ASCII character from a JSIN number.
* @return
*/
private static int bcd(char digit) {
if (digit >= '0' && digit <= '9') {
return digit - '0';
}
switch (digit) {
case '.':
return 10;
case '-':
return 11;
case '+':
return 12;
default:
return 13;
}
}
/**
* Finish the final byte and flush the bitwriter. This does the same thing
* as pad(8).
*
* @throws JSONException
*/
public void flush() throws JSONException {
pad(8);
}
/**
* Output a one bit.
*
* @throws IOException
*/
private void one() throws JSONException {
if (probe) {
log(1);
}
write(1, 1);
}
/**
* Pad the output to fill an allotment of bits.
*
* @param factor
* The size of the bit allotment. A value of 8 will complete and
* flush the current byte. If you don't pad, then some of the
* last bits might not be sent to the Output Stream.
* @throws JSONException
*/
public void pad(int factor) throws JSONException {
try {
this.bitwriter.pad(factor);
} catch (Throwable e) {
throw new JSONException(e);
}
}
/**
* Write a number, using the number of bits necessary to hold the number.
*
* @param integer
* The value to be encoded.
* @param width
* The number of bits to encode the value, between 0 and 32.
* @throws JSONException
*/
private void write(int integer, int width) throws JSONException {
try {
this.bitwriter.write(integer, width);
if (probe) {
log(integer, width);
}
} catch (Throwable e) {
throw new JSONException(e);
}
}
/**
* Write an integer with Huffman encoding. The bit pattern that is written
* will be determined by the Huffman encoder.
*
* @param integer
* The value to be written.
* @param huff
* The Huffman encoder.
* @throws JSONException
*/
private void write(int integer, Huff huff) throws JSONException {
huff.write(integer, this.bitwriter);
}
/**
* Write each of the bytes in a kim with Huffman encoding.
*
* @param kim
* A kim containing the bytes to be written.
* @param huff
* The Huffman encoder.
* @throws JSONException
*/
private void write(Kim kim, Huff huff) throws JSONException {
write(kim, 0, kim.length, huff);
}
/**
* Write a range of bytes from a Kim with Huffman encoding.
*
* @param kim
* A Kim containing the bytes to be written.
* @param from
* The index of the first byte to write.
* @param thru
* The index after the last byte to write.
* @param huff
* The Huffman encoder.
* @throws JSONException
*/
private void write(Kim kim, int from, int thru, Huff huff)
throws JSONException {
for (int at = from; at < thru; at += 1) {
write(kim.get(at), huff);
}
}
/**
* Write an integer, using the number of bits necessary to hold the number
* as determined by its keep, and increment its usage count in the keep.
*
* @param integer
* The value to be encoded.
* @param keep
* The Keep that the integer is one of.
* @throws JSONException
*/
private void writeAndTick(int integer, Keep keep) throws JSONException {
int width = keep.bitsize();
keep.tick(integer);
if (probe) {
log("\"" + keep.value(integer) + "\"");
}
write(integer, width);
}
/**
* Write a JSON Array.
*
* @param jsonarray
* @throws JSONException
*/
private void writeArray(JSONArray jsonarray) throws JSONException {
// JSONzip has three encodings for arrays:
// The array is empty (zipEmptyArray).
// First value in the array is a string (zipArrayString).
// First value in the array is not a string (zipArrayValue).
boolean stringy = false;
int length = jsonarray.length();
if (length == 0) {
write(zipEmptyArray, 3);
} else {
Object value = jsonarray.get(0);
if (value == null) {
value = JSONObject.NULL;
}
if (value instanceof String) {
stringy = true;
write(zipArrayString, 3);
writeString((String) value);
} else {
write(zipArrayValue, 3);
writeValue(value);
}
for (int i = 1; i < length; i += 1) {
if (probe) {
log();
}
value = jsonarray.get(i);
if (value == null) {
value = JSONObject.NULL;
}
if (value instanceof String != stringy) {
zero();
}
one();
if (value instanceof String) {
writeString((String) value);
} else {
writeValue(value);
}
}
zero();
zero();
}
}
/**
* Write a JSON value.
*
* @param value
* One of these types: JSONObject, JSONArray (or Map or
* Collection or array), Number (or Integer or Long or Double),
* or String, or Boolean, or JSONObject.NULL, or null.
* @throws JSONException
*/
private void writeJSON(Object value) throws JSONException {
if (JSONObject.NULL.equals(value)) {
write(zipNull, 3);
} else if (Boolean.FALSE.equals(value)) {
write(zipFalse, 3);
} else if (Boolean.TRUE.equals(value)) {
write(zipTrue, 3);
} else {
if (value instanceof Map) {
value = new JSONObject((Map) value);
} else if (value instanceof Collection) {
value = new JSONArray((Collection) value);
} else if (value.getClass().isArray()) {
value = new JSONArray(value);
}
if (value instanceof JSONObject) {
writeObject((JSONObject) value);
} else if (value instanceof JSONArray) {
writeArray((JSONArray) value);
} else {
throw new JSONException("Unrecognized object");
}
}
}
/**
* Write the name of an object property. Names have their own Keep and
* Huffman encoder because they are expected to be a more restricted set.
*
* @param name
* @throws JSONException
*/
private void writeName(String name) throws JSONException {
// If this name has already been registered, then emit its integer and
// increment its usage count.
Kim kim = new Kim(name);
int integer = this.namekeep.find(kim);
if (integer != none) {
one();
writeAndTick(integer, this.namekeep);
} else {
// Otherwise, emit the string with Huffman encoding, and register it.
zero();
write(kim, this.namehuff);
write(end, namehuff);
this.namekeep.register(kim);
}
}
/**
* Write a JSON object.
*
* @param jsonobject
* @return
* @throws JSONException
*/
private void writeObject(JSONObject jsonobject) throws JSONException {
// JSONzip has two encodings for objects: Empty Objects (zipEmptyObject) and
// non-empty objects (zipObject).
boolean first = true;
Iterator keys = jsonobject.keys();
while (keys.hasNext()) {
if (probe) {
log("\n");
}
Object key = keys.next();
if (key instanceof String) {
if (first) {
first = false;
write(zipObject, 3);
} else {
one();
}
writeName((String) key);
Object value = jsonobject.get((String) key);
if (value instanceof String) {
zero();
writeString((String) value);
} else {
one();
writeValue(value);
}
}
}
if (first) {
write(zipEmptyObject, 3);
} else {
zero();
}
}
/**
* Write a string.
*
* @param string
* @throws JSONException
*/
private void writeString(String string) throws JSONException {
// Special case for empty strings.
if (string.length() == 0) {
zero();
zero();
write(end, this.substringhuff);
zero();
} else {
Kim kim = new Kim(string);
// Look for the string in the strings keep. If it is found, emit its
// integer and count that as a use.
int integer = this.stringkeep.find(kim);
if (integer != none) {
one();
writeAndTick(integer, this.stringkeep);
} else {
// But if it is not found, emit the string's substrings. Register the string
// so that the next lookup will succeed.
writeSubstring(kim);
this.stringkeep.register(kim);
}
}
}
/**
* Write a string, attempting to match registered substrings.
*
* @param kim
* @throws JSONException
*/
private void writeSubstring(Kim kim) throws JSONException {
this.substringkeep.reserve();
zero();
int from = 0;
int thru = kim.length;
int until = thru - JSONzip.minSubstringLength;
int previousFrom = none;
int previousThru = 0;
// Find a substring from the substring keep.
while (true) {
int at;
int integer = none;
for (at = from; at <= until; at += 1) {
integer = this.substringkeep.match(kim, at, thru);
if (integer != none) {
break;
}
}
if (integer == none) {
break;
}
// If a substring is found, emit any characters that were before the matched
// substring. Then emit the substring's integer and loop back to match the
// remainder with another substring.
if (from != at) {
zero();
write(kim, from, at, this.substringhuff);
write(end, this.substringhuff);
if (previousFrom != none) {
this.substringkeep.registerOne(kim, previousFrom,
previousThru);
previousFrom = none;
}
}
one();
writeAndTick(integer, this.substringkeep);
from = at + this.substringkeep.length(integer);
if (previousFrom != none) {
this.substringkeep.registerOne(kim, previousFrom,
previousThru);
previousFrom = none;
}
previousFrom = at;
previousThru = from + 1;
}
// If a substring is not found, then emit the remaining characters.
zero();
if (from < thru) {
write(kim, from, thru, this.substringhuff);
if (previousFrom != none) {
this.substringkeep.registerOne(kim, previousFrom, previousThru);
}
}
write(end, this.substringhuff);
zero();
// Register the string's substrings in the trie in hopes of future substring
// matching.
substringkeep.registerMany(kim);
}
/**
* Write a value.
*
* @param value
* One of these types: Boolean, Number, etc.
* @throws JSONException
*/
private void writeValue(Object value) throws JSONException {
if (value instanceof Number) {
String string = JSONObject.numberToString((Number) value);
int integer = this.values.find(string);
if (integer != none) {
write(2, 2);
writeAndTick(integer, this.values);
return;
}
if (value instanceof Integer || value instanceof Long) {
long longer = ((Number) value).longValue();
if (longer >= 0 && longer < int14) {
write(0, 2);
if (longer < int4) {
zero();
write((int) longer, 4);
return;
}
one();
if (longer < int7) {
zero();
write((int) longer, 7);
return;
}
one();
write((int) longer, 14);
return;
}
}
write(1, 2);
for (int i = 0; i < string.length(); i += 1) {
write(bcd(string.charAt(i)), 4);
}
write(endOfNumber, 4);
this.values.register(string);
} else {
write(3, 2);
writeJSON(value);
}
}
/**
* Output a zero bit.
*
* @throws JSONException
*
* @throws IOException
*/
private void zero() throws JSONException {
if (probe) {
log(0);
}
write(0, 1);
}
/**
* Compress a JSONObject.
*
* @param jsonobject
* @throws JSONException
*/
public void zip(JSONObject jsonobject) throws JSONException {
begin();
writeJSON(jsonobject);
}
/**
* Compress a JSONArray.
*
* @param jsonarray
* @throws JSONException
*/
public void zip(JSONArray jsonarray) throws JSONException {
begin();
writeJSON(jsonarray);
}
}

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package org.json.zip;
import java.io.UnsupportedEncodingException;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.Kim;
/*
Copyright (c) 2012 JSON.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The Software shall be used for Good, not Evil.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
/**
* JSONzip is a compression scheme for JSON text.
*
* @author JSON.org
* @version 2013-04-18
*/
public class Decompressor extends JSONzip {
/**
* A decompressor reads bits from a BitReader.
*/
BitReader bitreader;
/**
* Create a new compressor. It may be used for an entire session or
* subsession.
*
* @param bitreader
* The bitreader that this decompressor will read from.
*/
public Decompressor(BitReader bitreader) {
super();
this.bitreader = bitreader;
}
/**
* Read one bit.
*
* @return true if 1, false if 0.
* @throws JSONException
*/
private boolean bit() throws JSONException {
boolean value;
try {
value = this.bitreader.bit();
if (probe) {
log(value ? 1 : 0);
}
return value;
} catch (Throwable e) {
throw new JSONException(e);
}
}
/**
* Read enough bits to obtain an integer from the keep, and increase that
* integer's weight.
*
* @param keep
* @param bitreader
* @return
* @throws JSONException
*/
private Object getAndTick(Keep keep, BitReader bitreader)
throws JSONException {
try {
int width = keep.bitsize();
int integer = bitreader.read(width);
Object value = keep.value(integer);
if (JSONzip.probe) {
JSONzip.log("\"" + value + "\"");
JSONzip.log(integer, width);
}
if (integer >= keep.length) {
throw new JSONException("Deep error.");
}
keep.tick(integer);
return value;
} catch (Throwable e) {
throw new JSONException(e);
}
}
/**
* The pad method skips the bits that padded a stream to fit some
* allocation. pad(8) will skip over the remainder of a byte.
*
* @param factor
* @return true if all of the padding bits were zero.
* @throws JSONException
*/
public boolean pad(int factor) throws JSONException {
try {
return this.bitreader.pad(factor);
} catch (Throwable e) {
throw new JSONException(e);
}
}
/**
* Read an integer, specifying its width in bits.
*
* @param width
* 0 to 32.
* @return An unsigned integer.
* @throws JSONException
*/
private int read(int width) throws JSONException {
try {
int value = this.bitreader.read(width);
if (probe) {
log(value, width);
}
return value;
} catch (Throwable e) {
throw new JSONException(e);
}
}
/**
* Read a JSONArray.
*
* @param stringy
* true if the first element is a string.
* @return
* @throws JSONException
*/
private JSONArray readArray(boolean stringy) throws JSONException {
JSONArray jsonarray = new JSONArray();
jsonarray.put(stringy ? readString() : readValue());
while (true) {
if (probe) {
log("\n");
}
if (!bit()) {
if (!bit()) {
return jsonarray;
}
jsonarray.put(stringy ? readValue() : readString());
} else {
jsonarray.put(stringy ? readString() : readValue());
}
}
}
/**
* Read a JSON value. The type of value is determined by the next 3 bits.
*
* @return
* @throws JSONException
*/
private Object readJSON() throws JSONException {
switch (read(3)) {
case zipObject:
return readObject();
case zipArrayString:
return readArray(true);
case zipArrayValue:
return readArray(false);
case zipEmptyObject:
return new JSONObject();
case zipEmptyArray:
return new JSONArray();
case zipTrue:
return Boolean.TRUE;
case zipFalse:
return Boolean.FALSE;
default:
return JSONObject.NULL;
}
}
private String readName() throws JSONException {
byte[] bytes = new byte[65536];
int length = 0;
if (!bit()) {
while (true) {
int c = this.namehuff.read(this.bitreader);
if (c == end) {
break;
}
bytes[length] = (byte) c;
length += 1;
}
if (length == 0) {
return "";
}
Kim kim = new Kim(bytes, length);
this.namekeep.register(kim);
return kim.toString();
}
return getAndTick(this.namekeep, this.bitreader).toString();
}
private JSONObject readObject() throws JSONException {
JSONObject jsonobject = new JSONObject();
while (true) {
if (probe) {
log("\n");
}
String name = readName();
jsonobject.put(name, !bit() ? readString() : readValue());
if (!bit()) {
return jsonobject;
}
}
}
private String readString() throws JSONException {
Kim kim;
int from = 0;
int thru = 0;
int previousFrom = none;
int previousThru = 0;
if (bit()) {
return getAndTick(this.stringkeep, this.bitreader).toString();
}
byte[] bytes = new byte[65536];
boolean one = bit();
this.substringkeep.reserve();
while (true) {
if (one) {
from = thru;
kim = (Kim) getAndTick(this.substringkeep, this.bitreader);
thru = kim.copy(bytes, from);
if (previousFrom != none) {
this.substringkeep.registerOne(new Kim(bytes, previousFrom,
previousThru + 1));
}
previousFrom = from;
previousThru = thru;
one = bit();
} else {
from = none;
while (true) {
int c = this.substringhuff.read(this.bitreader);
if (c == end) {
break;
}
bytes[thru] = (byte) c;
thru += 1;
if (previousFrom != none) {
this.substringkeep.registerOne(new Kim(bytes,
previousFrom, previousThru + 1));
previousFrom = none;
}
}
if (!bit()) {
break;
}
one = true;
}
}
if (thru == 0) {
return "";
}
kim = new Kim(bytes, thru);
this.stringkeep.register(kim);
this.substringkeep.registerMany(kim);
return kim.toString();
}
private Object readValue() throws JSONException {
switch (read(2)) {
case 0:
return new Integer(read(!bit() ? 4 : !bit() ? 7 : 14));
case 1:
byte[] bytes = new byte[256];
int length = 0;
while (true) {
int c = read(4);
if (c == endOfNumber) {
break;
}
bytes[length] = bcd[c];
length += 1;
}
Object value;
try {
value = JSONObject.stringToValue(new String(bytes, 0, length,
"US-ASCII"));
} catch (UnsupportedEncodingException e) {
throw new JSONException(e);
}
this.values.register(value);
return value;
case 2:
return getAndTick(this.values, this.bitreader);
case 3:
return readJSON();
default:
throw new JSONException("Impossible.");
}
}
public Object unzip() throws JSONException {
begin();
return readJSON();
}
}

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package org.json.zip;
import org.json.JSONException;
/*
Copyright (c) 2013 JSON.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The Software shall be used for Good, not Evil.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
/**
* JSONzip is a compression scheme for JSON text.
* @author JSON.org
* @version 2013-04-18
*/
/**
* A Huffman encoder/decoder. It operates over a domain of integers, which may
* map to characters or other symbols. Symbols that are used frequently are
* given shorter codes than symbols that are used infrequently. This usually
* produces shorter messages.
*
* Initially, all of the symbols are given the same weight. The weight of a
* symbol is incremented by the tick method. The generate method is used to
* generate the encoding table. The table must be generated before encoding or
* decoding. You may regenerate the table with the latest weights at any time.
*/
public class Huff implements None, PostMortem {
/**
* The number of symbols known to the encoder.
*/
private final int domain;
/**
* An array that maps symbol values to symbols.
*/
private final Symbol[] symbols;
/**
* The root of the decoding table, and the terminal of the encoding table.
*/
private Symbol table;
/**
* Have any weights changed since the table was last generated?
*/
private boolean upToDate = false;
/**
* The number of bits in the last symbol. This is used in tracing.
*/
private int width;
private static class Symbol implements PostMortem {
public Symbol back;
public Symbol next;
public Symbol zero;
public Symbol one;
public final int integer;
public long weight;
/**
* Make a symbol representing a character or other value.
*
* @param integer
* The symbol's number
*/
public Symbol(int integer) {
this.integer = integer;
this.weight = 0;
this.next = null;
this.back = null;
this.one = null;
this.zero = null;
}
public boolean postMortem(PostMortem pm) {
boolean result = true;
Symbol that = (Symbol) pm;
if (this.integer != that.integer || this.weight != that.weight) {
return false;
}
if ((this.back != null) != (that.back != null)) {
return false;
}
Symbol zero = this.zero;
Symbol one = this.one;
if (zero == null) {
if (that.zero != null) {
return false;
}
} else {
result = zero.postMortem(that.zero);
}
if (one == null) {
if (that.one != null) {
return false;
}
} else {
result = one.postMortem(that.one);
}
return result;
}
}
/**
* Construct a Huffman encoder/decoder.
*
* @param domain
* The number of values known to the object.
*/
public Huff(int domain) {
this.domain = domain;
int length = domain * 2 - 1;
this.symbols = new Symbol[length];
// Make the leaf symbols.
for (int i = 0; i < domain; i += 1) {
symbols[i] = new Symbol(i);
}
// SMake the links.
for (int i = domain; i < length; i += 1) {
symbols[i] = new Symbol(none);
}
}
/**
* Generate the encoding/decoding table. The table determines the bit
* sequences used by the read and write methods.
*
* @return this
*/
public void generate() {
if (!this.upToDate) {
// Phase One: Sort the symbols by weight into a linked list.
Symbol head = this.symbols[0];
Symbol next;
Symbol previous = head;
Symbol symbol;
this.table = null;
head.next = null;
for (int i = 1; i < this.domain; i += 1) {
symbol = symbols[i];
// If this symbol weights less than the head, then it becomes the new head.
if (symbol.weight < head.weight) {
symbol.next = head;
head = symbol;
} else {
// To save time, we will start the search from the previous symbol instead
// of the head unless the current symbol weights less than the previous symbol.
if (symbol.weight < previous.weight) {
previous = head;
}
// Find a connected pair (previous and next) where the symbol weighs the same
// or more than previous but less than the next. Link the symbol between them.
while (true) {
next = previous.next;
if (next == null || symbol.weight < next.weight) {
break;
}
previous = next;
}
symbol.next = next;
previous.next = symbol;
previous = symbol;
}
}
// Phase Two: Make new symbols from the two lightest symbols until only one
// symbol remains. The final symbol becomes the root of the table binary tree.
int avail = this.domain;
Symbol first;
Symbol second;
previous = head;
while (true) {
first = head;
second = first.next;
head = second.next;
symbol = this.symbols[avail];
avail += 1;
symbol.weight = first.weight + second.weight;
symbol.zero = first;
symbol.one = second;
symbol.back = null;
first.back = symbol;
second.back = symbol;
if (head == null) {
break;
}
// Insert the new symbol back into the sorted list.
if (symbol.weight < head.weight) {
symbol.next = head;
head = symbol;
previous = head;
} else {
while (true) {
next = previous.next;
if (next == null || symbol.weight < next.weight) {
break;
}
previous = next;
}
symbol.next = next;
previous.next = symbol;
previous = symbol;
}
}
// The last remaining symbol is the root of the table.
this.table = symbol;
this.upToDate = true;
}
}
private boolean postMortem(int integer) {
int[] bits = new int[this.domain];
Symbol symbol = this.symbols[integer];
if (symbol.integer != integer) {
return false;
}
int i = 0;
while (true) {
Symbol back = symbol.back;
if (back == null) {
break;
}
if (back.zero == symbol) {
bits[i] = 0;
} else if (back.one == symbol) {
bits[i] = 1;
} else {
return false;
}
i += 1;
symbol = back;
}
if (symbol != this.table) {
return false;
}
this.width = 0;
symbol = this.table;
while (symbol.integer == none) {
i -= 1;
symbol = bits[i] != 0 ? symbol.one : symbol.zero;
}
return symbol.integer == integer && i == 0;
}
/**
* Compare two Huffman tables.
*/
public boolean postMortem(PostMortem pm) {
// Go through every integer in the domain, generating its bit sequence, and
// then proving that that bit sequence produces the same integer.
for (int integer = 0; integer < this.domain; integer += 1) {
if (!postMortem(integer)) {
JSONzip.log("\nBad huff ");
JSONzip.logchar(integer, integer);
return false;
}
}
return this.table.postMortem(((Huff) pm).table);
}
/**
* Read bits until a symbol can be identified. The weight of the read
* symbol will be incremented.
*
* @param bitreader
* The source of bits.
* @return The integer value of the symbol.
* @throws JSONException
*/
public int read(BitReader bitreader) throws JSONException {
try {
this.width = 0;
Symbol symbol = this.table;
while (symbol.integer == none) {
this.width += 1;
symbol = bitreader.bit() ? symbol.one : symbol.zero;
}
tick(symbol.integer);
if (JSONzip.probe) {
JSONzip.logchar(symbol.integer, this.width);
}
return symbol.integer;
} catch (Throwable e) {
throw new JSONException(e);
}
}
/**
* Increase by 1 the weight associated with a value.
*
* @param value
* The number of the symbol to tick
* @return this
*/
public void tick(int value) {
this.symbols[value].weight += 1;
this.upToDate = false;
}
/**
* Increase by 1 the weight associated with a range of values.
*
* @param from
* The first symbol to tick
* @param to
* The last symbol to tick
* @return this
*/
public void tick(int from, int to) {
for (int value = from; value <= to; value += 1) {
tick(value);
}
}
/**
* Recur from a symbol back, emitting bits. We recur before emitting to
* make the bits come out in the right order.
*
* @param symbol
* The symbol to write.
* @param bitwriter
* The bitwriter to write it to.
* @throws JSONException
*/
private void write(Symbol symbol, BitWriter bitwriter)
throws JSONException {
try {
Symbol back = symbol.back;
if (back != null) {
this.width += 1;
write(back, bitwriter);
if (back.zero == symbol) {
bitwriter.zero();
} else {
bitwriter.one();
}
}
} catch (Throwable e) {
throw new JSONException(e);
}
}
/**
* Write the bits corresponding to a symbol. The weight of the symbol will
* be incremented.
*
* @param value
* The number of the symbol to write
* @param bitwriter
* The destination of the bits.
* @return this
* @throws JSONException
*/
public void write(int value, BitWriter bitwriter) throws JSONException {
this.width = 0;
write(this.symbols[value], bitwriter);
tick(value);
if (JSONzip.probe) {
JSONzip.logchar(value, this.width);
}
}
}

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package org.json.zip;
/*
Copyright (c) 2013 JSON.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The Software shall be used for Good, not Evil.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
/**
* JSONzip is a binary-encoded JSON dialect. It is designed to compress the
* messages in a session. It is adaptive, so with each message seen, it should
* improve its compression. It minimizes JSON's overhead, reducing punctuation
* to a small number of bits. It uses Huffman encoding to reduce the average
* size of characters. It uses caches (or Keeps) to keep recently seen strings
* and values, so repetitive content (such as object keys) can be
* substantially reduced. It uses a character encoding called Kim (Keep it
* minimal) that is smaller than UTF-8 for most East European, African, and
* Asian scripts.
*
* JSONzip tends to reduce most content by about half. If there is a lot of
* recurring information, the reduction can be much more dramatic.
*
* FOR EVALUATION PURPOSES ONLY. THIS PACKAGE HAS NOT YET BEEN TESTED
* ADEQUATELY FOR PRODUCTION USE.
*
* @author JSON.org
* @version 2013-04-18
*/
public abstract class JSONzip implements None, PostMortem {
/**
* Powers of 2.
*/
public static final int[] twos = {
1, 2, 4, 8, 16, 32, 64, 128, 256, 512,
1024, 2048, 4096, 8192, 16384, 32768, 65536
};
/**
* The characters in JSON numbers can be reduced to 4 bits each.
*/
public static final byte[] bcd = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '.', '-', '+', 'E'
};
/**
* The number of integers that can be encoded in 4 bits.
*/
public static final long int4 = 16;
/**
* The number of integers that can be encoded in 7 bits.
*/
public static final long int7 = 128;
/**
* The number of integers that can be encoded in 14 bits.
*/
public static final long int14 = 16384;
/**
* The end of string code.
*/
public static final int end = 256;
/**
* The end of number code.
*/
public static final int endOfNumber = bcd.length;
/**
* The maximum substring length when registering many. The registration of
* one substring may be longer.
*/
public static final int maxSubstringLength = 10;
/**
* The minimum substring length.
*/
public static final int minSubstringLength = 3;
/**
* The package supports tracing for debugging.
*/
public static final boolean probe = false;
/**
* The maximum number of substrings added to the substrings keep per
* string.
*/
public static final int substringLimit = 40;
/**
* The value code for an empty object.
*/
public static final int zipEmptyObject = 0;
/**
* The value code for an empty array.
*/
public static final int zipEmptyArray = 1;
/**
* The value code for true.
*/
public static final int zipTrue = 2;
/**
* The value code for false.
*/
public static final int zipFalse = 3;
/**
* The value code for null.
*/
public static final int zipNull = 4;
/**
* The value code for a non-empty object.
*/
public static final int zipObject = 5;
/**
* The value code for an array with a string as its first element.
*/
public static final int zipArrayString = 6;
/**
* The value code for an array with a non-string value as its first element.
*/
public static final int zipArrayValue = 7;
/**
* A Huffman encoder for names.
*/
protected final Huff namehuff;
/**
* A place to keep the names (keys).
*/
protected final MapKeep namekeep;
/**
* A place to keep the strings.
*/
protected final MapKeep stringkeep;
/**
* A Huffman encoder for string values.
*/
protected final Huff substringhuff;
/**
* A place to keep the strings.
*/
protected final TrieKeep substringkeep;
/**
* A place to keep the values.
*/
protected final MapKeep values;
/**
* Initialize the data structures.
*/
protected JSONzip() {
this.namehuff = new Huff(end + 1);
this.namekeep = new MapKeep(9);
this.stringkeep = new MapKeep(11);
this.substringhuff = new Huff(end + 1);
this.substringkeep = new TrieKeep(12);
this.values = new MapKeep(10);
// Increase the weights of the ASCII letters, digits, and special characters
// because they are highly likely to occur more frequently. The weight of each
// character will increase as it is used. The Huffman encoder will tend to
// use fewer bits to encode heavier characters.
this.namehuff.tick(' ', '}');
this.namehuff.tick('a', 'z');
this.namehuff.tick(end);
this.namehuff.tick(end);
this.substringhuff.tick(' ', '}');
this.substringhuff.tick('a', 'z');
this.substringhuff.tick(end);
this.substringhuff.tick(end);
}
/**
*
*/
protected void begin() {
this.namehuff.generate();
this.substringhuff.generate();
}
/**
* Write an end-of-line to the console.
*/
static void log() {
log("\n");
}
/**
* Write an integer to the console.
*
* @param integer
*/
static void log(int integer) {
log(integer + " ");
}
/**
* Write two integers, separated by ':' to the console.
*
* @param integer
* @param width
*/
static void log(int integer, int width) {
log(integer + ":" + width + " ");
}
/**
* Write a string to the console.
*
* @param string
*/
static void log(String string) {
System.out.print(string);
}
/**
* Write a character or its code to the console.
*
* @param integer
* @param width
*/
static void logchar(int integer, int width) {
if (integer > ' ' && integer <= '}') {
log("'" + (char) integer + "':" + width + " ");
} else {
log(integer, width);
}
}
/**
* This method is used for testing the implementation of JSONzip. It is not
* suitable for any other purpose. It is used to compare a Compressor and a
* Decompressor, verifying that the data structures that were built during
* zipping and unzipping were the same.
*
* @return true if the structures match.
*/
public boolean postMortem(PostMortem pm) {
JSONzip that = (JSONzip) pm;
return this.namehuff.postMortem(that.namehuff)
&& this.namekeep.postMortem(that.namekeep)
&& this.stringkeep.postMortem(that.stringkeep)
&& this.substringhuff.postMortem(that.substringhuff)
&& this.substringkeep.postMortem(that.substringkeep)
&& this.values.postMortem(that.values);
}
}

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package org.json.zip;
/*
Copyright (c) 2013 JSON.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The Software shall be used for Good, not Evil.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
/**
* A keep is a data structure that associates strings (or substrings) with
* numbers. This allows the sending of small integers instead of strings.
*
* @author JSON.org
* @version 2013-04-18
*/
abstract class Keep implements None, PostMortem {
protected int capacity;
protected int length;
protected int power;
protected long[] uses;
public Keep(int bits) {
this.capacity = JSONzip.twos[bits];
this.length = 0;
this.power = 0;
this.uses = new long[this.capacity];
}
/**
* When an item ages, its use count is reduced by at least half.
*
* @param use
* The current use count of an item.
* @return The new use count for that item.
*/
public static long age(long use) {
return use >= 32 ? 16 : use / 2;
}
/**
* Return the number of bits required to contain an integer based on the
* current length of the keep. As the keep fills up, the number of bits
* required to identify one of its items goes up.
*/
public int bitsize() {
while (JSONzip.twos[this.power] < this.length) {
this.power += 1;
}
return this.power;
}
/**
* Increase the usage count on an integer value.
*/
public void tick(int integer) {
this.uses[integer] += 1;
}
/**
* Get the value associated with an integer.
* @param integer The number of an item in the keep.
* @return The value.
*/
abstract public Object value(int integer);
}

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package org.json.zip;
import java.util.HashMap;
import org.json.Kim;
/*
Copyright (c) 2013 JSON.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The Software shall be used for Good, not Evil.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
/**
* A keep is an associative data structure that maintains usage counts of each
* of the associations in its keeping. When the keep becomes full, it purges
* little used associations, and ages the survivors. Each key is assigned an
* integer value. When the keep is compacted, each key can be given a new
* value.
*/
class MapKeep extends Keep {
private Object[] list;
private HashMap map;
/**
* Create a new Keep.
* @param bits
* The capacity of the keep expressed in the number of bits
* required to hold an integer.
*/
public MapKeep(int bits) {
super(bits);
this.list = new Object[this.capacity];
this.map = new HashMap(this.capacity);
}
/**
* Compact the keep. A keep may contain at most this.capacity elements.
* The keep contents can be reduced by deleting all elements with low use
* counts, and by reducing the use counts of the survivors.
*/
private void compact() {
int from = 0;
int to = 0;
while (from < this.capacity) {
Object key = this.list[from];
long usage = age(this.uses[from]);
if (usage > 0) {
this.uses[to] = usage;
this.list[to] = key;
this.map.put(key, new Integer(to));
to += 1;
} else {
this.map.remove(key);
}
from += 1;
}
if (to < this.capacity) {
this.length = to;
} else {
this.map.clear();
this.length = 0;
}
this.power = 0;
}
/**
* Find the integer value associated with this key, or nothing if this key
* is not in the keep.
*
* @param key
* An object.
* @return An integer
*/
public int find(Object key) {
Object o = this.map.get(key);
return o instanceof Integer ? ((Integer) o).intValue() : none;
}
public boolean postMortem(PostMortem pm) {
MapKeep that = (MapKeep) pm;
if (this.length != that.length) {
JSONzip.log(this.length + " <> " + that.length);
return false;
}
for (int i = 0; i < this.length; i += 1) {
boolean b;
if (this.list[i] instanceof Kim) {
b = ((Kim) this.list[i]).equals(that.list[i]);
} else {
Object o = this.list[i];
Object q = that.list[i];
if (o instanceof Number) {
o = o.toString();
}
if (q instanceof Number) {
q = q.toString();
}
b = o.equals(q);
}
if (!b) {
JSONzip.log("\n[" + i + "]\n " + this.list[i] + "\n "
+ that.list[i] + "\n " + this.uses[i] + "\n "
+ that.uses[i]);
return false;
}
}
return true;
}
/**
* Register a value in the keep. Compact the keep if it is full. The next
* time this value is encountered, its integer can be sent instead.
* @param value A value.
*/
public void register(Object value) {
if (JSONzip.probe) {
int integer = find(value);
if (integer >= 0) {
JSONzip.log("\nDuplicate key " + value);
}
}
if (this.length >= this.capacity) {
compact();
}
this.list[this.length] = value;
this.map.put(value, new Integer(this.length));
this.uses[this.length] = 1;
if (JSONzip.probe) {
JSONzip.log("<" + this.length + " " + value + "> ");
}
this.length += 1;
}
/**
* Return the value associated with the integer.
* @param integer The number of an item in the keep.
* @return The value.
*/
public Object value(int integer) {
return this.list[integer];
}
}

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package org.json.zip;
/**
* None is an interface that makes the constant <i>none</i> (short for
* negative one or long for -1) available to any class that implements it.
* The none value is used to stand for an integer that is not an integer,
* such as the negative result of a search.
*/
public interface None {
/**
* Negative One.
*/
public static final int none = -1;
}

47
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package org.json.zip;
/*
Copyright (c) 2013 JSON.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The Software shall be used for Good, not Evil.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
/**
* The PostMortem interface allows for testing the internal state of JSONzip
* processors. Testing that JSONzip can compress an object and reproduce a
* corresponding object is not sufficient. Complete testing requires that the
* same internal data structures were constructed on both ends. If those
* structures are not equivalent, then it is likely that the implementations
* are not correct, even if convention tests are passed.
*
* PostMortem allows for testing of deep structures without breaking
* encapsulation.
*/
public interface PostMortem {
/**
* Determine if two objects are equivalent.
*
* @param pm
* Another object of the same type.
* @return true if they match.
*/
public boolean postMortem(PostMortem pm);
}

2
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FOR EVALUATION PURPOSES ONLY. THIS PACKAGE HAS NOT BEEN TESTED ADEQUATELY FOR
PRODUCTION USE.

396
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package org.json.zip;
import org.json.Kim;
/*
Copyright (c) 2013 JSON.org
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
The Software shall be used for Good, not Evil.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
/**
* A TrieKeep is a Keep that implements a Trie.
*/
class TrieKeep extends Keep {
/**
* The trie is made of nodes.
*/
class Node implements PostMortem {
private int integer;
private Node[] next;
/**
* Each non-leaf node contains links to up to 256 next nodes. Each node
* has an integer value.
*/
public Node() {
this.integer = none;
this.next = null;
}
/**
* Get one of a node's 256 links. If it is a leaf node, it returns
* null.
*
* @param cell
* A integer between 0 and 255.
* @return
*/
public Node get(int cell) {
return this.next == null ? null : this.next[cell];
}
/**
* Get one of a node's 256 links. If it is a leap node, it returns
* null. The argument is treated as an unsigned integer.
*
* @param cell
* A byte.
* @return
*/
public Node get(byte cell) {
return get(((int) cell) & 0xFF);
}
/**
* Compare two nodes. Their lengths must be equal. Their links must
* also compare.
*/
public boolean postMortem(PostMortem pm) {
Node that = (Node) pm;
if (that == null) {
JSONzip.log("\nMisalign");
return false;
}
if (this.integer != that.integer) {
JSONzip.log("\nInteger " + this.integer + " <> " +
that.integer);
return false;
}
if (this.next == null) {
if (that.next == null) {
return true;
}
JSONzip.log("\nNext is null " + this.integer);
return false;
}
for (int i = 0; i < 256; i += 1) {
Node node = this.next[i];
if (node != null) {
if (!node.postMortem(that.next[i])) {
return false;
}
} else if (that.next[i] != null) {
JSONzip.log("\nMisalign " + i);
return false;
}
}
return true;
}
/**
* Set a node's link to another node.
*
* @param cell
* An integer between 0 and 255.
* @param node
* The new value for the cell.
*/
public void set(int cell, Node node) {
if (this.next == null) {
this.next = new Node[256];
}
if (JSONzip.probe) {
if (node == null || this.next[cell] != null) {
JSONzip.log("\nUnexpected set.\n");
}
}
this.next[cell] = node;
}
/**
* Set a node's link to another node.
*
* @param cell
* A byte.
* @param node
* The new value for the cell.
*/
public void set(byte cell, Node node) {
set(((int) cell) & 0xFF, node);
}
/**
* Get one of a node's 256 links. It will not return null. If there is
* no link, then a link is manufactured.
*
* @param cell
* A integer between 0 and 255.
* @return
*/
public Node vet(int cell) {
Node node = get(cell);
if (node == null) {
node = new Node();
set(cell, node);
}
return node;
}
/**
* Get one of a node's 256 links. It will not return null. If there is
* no link, then a link is manufactured.
*
* @param cell
* A byte.
* @return
*/
public Node vet(byte cell) {
return vet(((int) cell) & 0xFF);
}
}
private int[] froms;
private int[] thrus;
private Node root;
private Kim[] kims;
/**
* Create a new Keep of kims.
*
* @param bits
* The log2 of the capacity of the Keep. For example, if bits is
* 12, then the keep's capacity will be 4096.
*/
public TrieKeep(int bits) {
super(bits);
this.froms = new int[this.capacity];
this.thrus = new int[this.capacity];
this.kims = new Kim[this.capacity];
this.root = new Node();
}
/**
* Get the kim associated with an integer.
*
* @param integer
* @return
*/
public Kim kim(int integer) {
Kim kim = this.kims[integer];
int from = this.froms[integer];
int thru = this.thrus[integer];
if (from != 0 || thru != kim.length) {
kim = new Kim(kim, from, thru);
this.froms[integer] = 0;
this.thrus[integer] = kim.length;
this.kims[integer] = kim;
}
return kim;
}
/**
* Get the length of the Kim associated with an integer. This is sometimes
* much faster than get(integer).length.
*
* @param integer
* @return
*/
public int length(int integer) {
return this.thrus[integer] - this.froms[integer];
}
/**
* Find the integer value associated with this key, or nothing if this key
* is not in the keep.
*
* @param key
* An object.
* @return An integer
*/
public int match(Kim kim, int from, int thru) {
Node node = this.root;
int best = none;
for (int at = from; at < thru; at += 1) {
node = node.get(kim.get(at));
if (node == null) {
break;
}
if (node.integer != none) {
best = node.integer;
}
from += 1;
}
return best;
}
public boolean postMortem(PostMortem pm) {
boolean result = true;
TrieKeep that = (TrieKeep) pm;
if (this.length != that.length) {
JSONzip.log("\nLength " + this.length + " <> " + that.length);
return false;
}
if (this.capacity != that.capacity) {
JSONzip.log("\nCapacity " + this.capacity + " <> " +
that.capacity);
return false;
}
for (int i = 0; i < this.length; i += 1) {
Kim thiskim = this.kim(i);
Kim thatkim = that.kim(i);
if (!thiskim.equals(thatkim)) {
JSONzip.log("\n[" + i + "] " + thiskim + " <> " + thatkim);
result = false;
}
}
return result && this.root.postMortem(that.root);
}
public void registerMany(Kim kim) {
int length = kim.length;
int limit = this.capacity - this.length;
if (limit > JSONzip.substringLimit) {
limit = JSONzip.substringLimit;
}
int until = length - (JSONzip.minSubstringLength - 1);
for (int from = 0; from < until; from += 1) {
int len = length - from;
if (len > JSONzip.maxSubstringLength) {
len = JSONzip.maxSubstringLength;
}
len += from;
Node node = this.root;
for (int at = from; at < len; at += 1) {
Node next = node.vet(kim.get(at));
if (next.integer == none
&& at - from >= (JSONzip.minSubstringLength - 1)) {
next.integer = this.length;
this.uses[this.length] = 1;
this.kims[this.length] = kim;
this.froms[this.length] = from;
this.thrus[this.length] = at + 1;
if (JSONzip.probe) {
try {
JSONzip.log("<<" + this.length + " "
+ new Kim(kim, from, at + 1) + ">> ");
} catch (Throwable ignore) {
}
}
this.length += 1;
limit -= 1;
if (limit <= 0) {
return;
}
}
node = next;
}
}
}
public void registerOne(Kim kim) {
int integer = registerOne(kim, 0, kim.length);
if (integer != none) {
this.kims[integer] = kim;
}
}
public int registerOne(Kim kim, int from, int thru) {
if (this.length < this.capacity) {
Node node = this.root;
for (int at = from; at < thru; at += 1) {
node = node.vet(kim.get(at));
}
if (node.integer == none) {
int integer = this.length;
node.integer = integer;
this.uses[integer] = 1;
this.kims[integer] = kim;
this.froms[integer] = from;
this.thrus[integer] = thru;
if (JSONzip.probe) {
try {
JSONzip.log("<<" + integer + " " + new Kim(kim, from, thru) + ">> ");
} catch (Throwable ignore) {
}
}
this.length += 1;
return integer;
}
}
return none;
}
/**
* Reserve space in the keep, compacting if necessary. A keep may contain
* at most -capacity- elements. The keep contents can be reduced by
* deleting all elements with low use counts, rebuilding the trie with the
* survivors.
*/
public void reserve() {
if (this.capacity - this.length < JSONzip.substringLimit) {
int from = 0;
int to = 0;
this.root = new Node();
while (from < this.capacity) {
if (this.uses[from] > 1) {
Kim kim = this.kims[from];
int thru = this.thrus[from];
Node node = this.root;
for (int at = this.froms[from]; at < thru; at += 1) {
Node next = node.vet(kim.get(at));
node = next;
}
node.integer = to;
this.uses[to] = age(this.uses[from]);
this.froms[to] = this.froms[from];
this.thrus[to] = thru;
this.kims[to] = kim;
to += 1;
}
from += 1;
}
// It is possible, but highly unlikely, that too many items survive.
// If that happens, clear the keep.
if (this.capacity - to < JSONzip.substringLimit) {
this.power = 0;
this.root = new Node();
to = 0;
}
this.length = to;
while (to < this.capacity) {
this.uses[to] = 0;
this.kims[to] = null;
this.froms[to] = 0;
this.thrus[to] = 0;
to += 1;
}
}
}
public Object value(int integer) {
return kim(integer);
}
}