package org.json.zip;
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 binary compression scheme for JSON text.
*
* @author JSON.org
* @version 2014-05-03
*/
public class Unzipper extends JSONzip {
/**
* A decoder reads bits from a BitReader.
*/
BitReader bitreader;
/**
* Create a new unzipper. It may be used for an entire session or
* subsession.
*
* @param bitreader
* The bitreader that this decoder will read from.
*/
public Unzipper(final 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 (final Throwable e) {
throw new JSONException(e);
}
}
/**
* Read enough bits to obtain an integer from the keep, and increase that
* integer's weight.
*
* @param keep
* The keep providing the context.
* @param bitreader
* The bitreader that is the source of bits.
* @return The value associated with the number.
* @throws JSONException
*/
private Object getAndTick(final Keep keep, final BitReader bitreader)
throws JSONException {
try {
final int width = keep.bitsize();
final int integer = bitreader.read(width);
final 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 (final 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 width
* The width of the pad field in bits.
* @return true if all of the padding bits were zero.
* @throws JSONException
*/
public boolean pad(final int width) throws JSONException {
try {
return this.bitreader.pad(width);
} catch (final 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(final int width) throws JSONException {
try {
final int value = this.bitreader.read(width);
if (probe) {
log(value, width);
}
return value;
} catch (final Throwable e) {
throw new JSONException(e);
}
}
/**
* Read Huffman encoded characters into a keep.
*
* @param huff
* A Huffman decoder.
* @param ext
* A Huffman decoder for the extended bytes.
* @param keep
* The keep that will receive the kim.
* @return The string that was read.
* @throws JSONException
*/
private String read(final Huff huff, final Huff ext, final Keep keep)
throws JSONException {
Kim kim;
int at = 0;
int allocation = 256;
byte[] bytes = new byte[allocation];
if (bit()) {
return getAndTick(keep, this.bitreader).toString();
}
while (true) {
if (at >= allocation) {
allocation *= 2;
bytes = java.util.Arrays.copyOf(bytes, allocation);
}
int c = huff.read(this.bitreader);
if (c == end) {
break;
}
while ((c & 128) == 128) {
bytes[at] = (byte) c;
at += 1;
c = ext.read(this.bitreader);
}
bytes[at] = (byte) c;
at += 1;
}
if (at == 0) {
return "";
}
kim = new Kim(bytes, at);
keep.register(kim);
return kim.toString();
}
/**
* Read a JSONArray.
*
* @param stringy
* true if the first element is a string.
* @throws JSONException
*/
private JSONArray readArray(final boolean stringy) throws JSONException {
final JSONArray jsonarray = new JSONArray();
jsonarray.put(stringy ? read(this.stringhuff, this.stringhuffext,
this.stringkeep) : readValue());
while (true) {
if (probe) {
log();
}
if (!bit()) {
if (!bit()) {
return jsonarray;
}
jsonarray.put(stringy ? readValue() : read(this.stringhuff,
this.stringhuffext, this.stringkeep));
} else {
jsonarray.put(stringy ? read(this.stringhuff,
this.stringhuffext, this.stringkeep) : readValue());
}
}
}
/**
* Read a JSON value. The type of value is determined by the next 3 bits.
*
* @return The read value.
* @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 JSONObject readObject() throws JSONException {
final JSONObject jsonobject = new JSONObject();
while (true) {
if (probe) {
log();
}
final String name = read(this.namehuff, this.namehuffext,
this.namekeep);
if (jsonobject.opt(name) != null) {
throw new JSONException("Duplicate key.");
}
jsonobject.put(
name,
!bit() ? read(this.stringhuff, this.stringhuffext,
this.stringkeep) : readValue());
if (!bit()) {
return jsonobject;
}
}
}
private Object readValue() throws JSONException {
switch (read(2)) {
case 0:
final int nr_bits = !bit() ? 4 : !bit() ? 7 : 14;
int integer = read(nr_bits);
switch (nr_bits) {
case 7:
integer += int4;
break;
case 14:
integer += int7;
break;
}
return integer;
case 1:
final byte[] bytes = new byte[256];
int length = 0;
while (true) {
final 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 (final java.io.UnsupportedEncodingException e) {
throw new JSONException(e);
}
this.valuekeep.register(value);
return value;
case 2:
return getAndTick(this.valuekeep, this.bitreader);
case 3:
return readJSON();
default:
throw new JSONException("Impossible.");
}
}
public Object decode() throws JSONException {
generate();
return readJSON();
}
}
