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Merged
myibu merged 1 commit into from
Aug 9, 2022
Merged

add more method for Bits #9

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2 changes: 1 addition & 1 deletion build.gradle
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ tasks.withType(JavaCompile) { options.encoding = "UTF-8" }

group = 'com.github.myibu'
archivesBaseName = "algorithm-java"
version = "1.0.0e"
version = "1.0.0f"

repositories {
mavenCentral()
Expand Down
2 changes: 1 addition & 1 deletion readme.md
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Expand Up @@ -57,7 +57,7 @@ Reference to: [HoffmanAndGolombCoding.pdf](./docs/HoffmanAndGolombCoding.pdf)
<dependency>
<groupId>com.github.myibu</groupId>
<artifactId>algorithm-java</artifactId>
<version>1.0.0e</version>
<version>1.0.0f</version>
</dependency>
```

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95 changes: 94 additions & 1 deletion src/main/java/com/github/myibu/algorithm/data/Bits.java
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Expand Up @@ -3,6 +3,7 @@
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

/**
Expand Down Expand Up @@ -546,8 +547,19 @@ static void subBitsRangeCheck(int fromIndex, int toIndex, int size) {
") > toIndex(" + toIndex + ")");
}

@Deprecated
public Bit[] table(){
return this.table;
return toArray();
}

public Bit[] toArray() {
return Arrays.copyOf(table, used);
}

public List<Bit> toList() {
Bit[] usedTable = new Bit[used];
System.arraycopy(table, 0, usedTable, 0, used);
return Arrays.asList(usedTable);
}

@Override
Expand Down Expand Up @@ -593,6 +605,14 @@ public Bit get(int index) {
return table[index];
}

public Bit set(int index, Bit bit) {
if (index < 0 || index >= used)
throw new IndexOutOfBoundsException();
Bit oldValue = table[index];
table[index] = bit;
return oldValue;
}

@Override
public Bits clone() {
Bits dest = null;
Expand All @@ -618,4 +638,77 @@ public boolean equals(Object o) {
public int hashCode() {
return Arrays.hashCode(table);
}

public static void copy(Bits src, int srcPos, Bits dest, int destPos, int length) {
System.arraycopy(src.table, srcPos, dest.table, destPos, length);
}

public static class Encoder {
public static Bits encodeIntValue(int value) {
Bits bits = new Bits();
int div = 0;
while ((div = (value / 2)) != 0) {
int left = value - div * 2;
bits.append(left == 0 ? Bit.ZERO : Bit.ONE);
value = div;
}
bits.append(value == 1 ? Bit.ONE : Bit.ZERO);
return Bits.reverse(bits);
}

public static Bits encodeDecimalValue(double value) {
Bits bits = new Bits();
while (!firstNumAfterDotIsZero(value)) {
int left = (int)(value * 2);
bits.append(left == 0 ? Bit.ZERO : Bit.ONE);
value = value * 2 - left;
}
return bits;
}

private static boolean firstNumAfterDotIsZero(double value) {
String doubleValue = "" + value;
int dotIndex = -1;
if ((dotIndex = doubleValue.indexOf(".")) != -1) {
if (dotIndex + 1 < doubleValue.length()) {
return doubleValue.charAt(dotIndex+1) == '0';
}
}
return false;
}

public static Bits encodeFloatValue(float value) {
int intValue = (int)value;
float dotValue = value - intValue;
Bits bits1 = encodeIntValue(intValue);
Bits bits2 = encodeDecimalValue(dotValue);
Bits S = value < 0 ? Bits.ofOne() : Bits.ofZero();
Bits E = Bits.ofZero(8);
Bits eValue = encodeIntValue(bits1.length() - 1 + 127);
Bits.copy(eValue, 0, E, 0,8);
Bits M = Bits.ofZero(23);
Bits.copy(bits1, 1, M, 0, bits1.length() - 1);
Bits.copy(bits2, 0, M, bits1.length() - 1, bits2.length());
return S.append(E).append(M);
}

public static Bits encodeDoubleValue(double value) {
int intValue = (int)value;
double dotValue = value - intValue;
Bits bits1 = encodeIntValue(intValue);
Bits bits2 = encodeDecimalValue(dotValue);
Bits S = value < 0 ? Bits.ofOne() : Bits.ofZero();
Bits E = Bits.ofZero(11);
Bits eValue = encodeIntValue(bits1.length() - 1 + 1023);
Bits.copy(eValue, 0, E, 0,11);
Bits M = Bits.ofZero(52);
Bits.copy(bits1, 1, M, 0, bits1.length() - 1);
Bits.copy(bits2, 0, M, bits1.length() - 1, bits2.length());
return S.append(E).append(M);
}

public static Bits encodeStringValue(String value) {
return Bits.ofByte(value.getBytes(StandardCharsets.UTF_8));
}
}
}