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PlantUML is a component that allows to quickly write diagrams from text.
// THIS FILE HAS BEEN GENERATED BY A PREPROCESSOR.
/* +=======================================================================
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* | PlantUML : a free UML diagram generator
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* (C) Copyright 2009-2024, Arnaud Roques
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*/
package net.sourceforge.plantuml.webp;
import java.io.IOException;
import javax.imageio.stream.ImageInputStream;
public class BoolDecoder {
// ::remove folder when __HAXE__
// ::remove folder when __CORE__
// ::remove folder when __MIT__ or __EPL__ or __BSD__ or __ASL__ or __LGPL__
int bit_count; /* # of bits shifted out of value, at most 7 */
ImageInputStream data;
private long offset; /* pointer to next compressed data byte */
private int range; /* always identical to encoder's range */
private int value; /* contains at least 24 significant bits */
BoolDecoder(ImageInputStream frame, long offset) throws IOException {
this.data = frame;
this.offset = offset;
initBoolDecoder();
}
private void initBoolDecoder() throws IOException {
value = 0; /* value = first 16 input bits */
data.seek(offset);
value = data.readUnsignedByte() << 8;
// value = (data[offset]) << 8;
offset++;
range = 255; /* initial range is full */
bit_count = 0; /* have not yet shifted out any bits */
}
public int readBit() throws IOException {
return readBool(128);
}
public int readBool(int probability) throws IOException {
int bit = 0;
int split;
int bigsplit;
int range = this.range;
int value = this.value;
split = 1 + (((range - 1) * probability) >> 8);
bigsplit = (split << 8);
range = split;
if (value >= bigsplit) {
range = this.range - split;
value = value - bigsplit;
bit = 1;
}
{
int count = this.bit_count;
int shift = Globals.vp8dxBitreaderNorm[range];
range <<= shift;
value <<= shift;
count -= shift;
if (count <= 0) {
// data.seek(offset);
value |= data.readUnsignedByte() << (-count);
// value |= data[offset] << (-count);
offset++;
count += 8;
}
this.bit_count = count;
}
this.value = value;
this.range = range;
return bit;
}
/*
* Convenience function reads a "literal", that is, a "num_bits" wide unsigned
* value whose bits come high- to low-order, with each bit encoded at
* probability 128 (i.e., 1/2).
*/
public int readLiteral(int num_bits) throws IOException {
int v = 0;
while (num_bits-- > 0)
v = (v << 1) + readBool(128);
return v;
}
int readTree(int t[], /* tree specification */
int p[] /* corresponding interior node probabilities */
) throws IOException {
int i = 0; /* begin at root */
/* Descend tree until leaf is reached */
while ((i = t[i + readBool(p[i >> 1])]) > 0) {
}
return -i; /* return value is negation of nonpositive index */
}
int readTreeSkip(int t[], /* tree specification */
int p[], /* corresponding interior node probabilities */
int skip_branches) throws IOException {
int i = skip_branches * 2; /* begin at root */
/* Descend tree until leaf is reached */
while ((i = t[i + readBool(p[i >> 1])]) > 0) {
}
return -i; /* return value is negation of nonpositive index */
}
public void seek() throws IOException {
data.seek(offset);
}
public String toString() {
return "bc: " + value;
}
}