add lz77 compress

Author: 15045120

src/main/java/com/github/myibu/algorithm/compress/LZ77Compressor.java

@@ -1,6 +1,11 @@
 package com.github.myibu.algorithm.compress;
 
+import com.github.myibu.algorithm.data.Bits;
+import com.github.myibu.algorithm.endode.GolombEncoder;
+
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 
 /**
  * LZ77 compress algorithm
@@ -48,6 +53,7 @@ public int compress(byte[] in_data, int in_len, byte[] out_data) {
  System.arraycopy(in_data, 0, out_data, 0, in_len);
  return in_len;
  }
+ List<List<Integer>> tuples = new ArrayList<>();
  // search buffer
  byte[] sBuf = new byte[s];
  // look ahead window
@@ -87,6 +93,7 @@ public int compress(byte[] in_data, int in_len, byte[] out_data) {
 // byte[] tuple = String.format("(%d,%d,%s)", minIndex + 1, minMatched, new String(new byte[]{lWindow[minMatched]})).getBytes();
 // System.arraycopy(tuple, 0, out_data, (op++) * tuple.length, tuple.length);
  System.out.println(String.format("(%d, %d, %s)", minIndex + 1, minMatched, new String(new byte[]{lWindow[minMatched]})));
+ tuples.add(Arrays.asList( minIndex + 1, minMatched, (int)lWindow[minMatched]));
  sp += (minMatched + 1);
 // if (sp > s) {
 // sp = s-1;
@@ -101,8 +108,23 @@ public int compress(byte[] in_data, int in_len, byte[] out_data) {
 // byte[] tuple = String.format("(%d,%d,%s)", 0, 0, new String(new byte[]{lWindow[0]})).getBytes();
 // System.arraycopy(tuple, 0, out_data, (op++) * tuple.length, tuple.length);
  System.out.println(String.format("(%d, %d, %s)", 0, 0, new String(new byte[]{lWindow[0]})));
+ tuples.add(Arrays.asList(0, 0, (int)lWindow[0]));
  }
  }
+ System.out.println(tuples);
+ int sum = 0;
+ GolombEncoder encoder = new GolombEncoder();
+ for (List<Integer> tuple: tuples) {
+ Bits bits = new Bits();
+ bits.append(encoder.encodeToBinary(tuple.get(0), (int)(Math.ceil(Math.log(s) / Math.log(2)))));
+ System.out.println("1" + bits);
+ bits.append(encoder.encode(tuple.get(1), 5));
+ System.out.println("2" + bits);
+ bits.append(Bits.ofByte((byte)tuple.get(2).intValue()));
+ System.out.println("3" + bits);
+ sum += bits.length();
+ }
+ System.out.println("compressed length: " + sum);
  return 0;
  }
 

src/main/java/com/github/myibu/algorithm/endode/GolombEncoder.java

@@ -35,7 +35,7 @@ public Bits encode(int n, int m) {
  }
  }
 
- private Bits encodeToTruncatedBinary(int x, int n) {
+ public static Bits encodeToTruncatedBinary(int x, int n) {
  // Set k = floor(log2(n)), i.e., k such that 2^k <= n < 2^(k+1).
  int k = 0, t = n;
  while (t > 1) { k++; t >>= 1; }
@@ -47,7 +47,7 @@ private Bits encodeToTruncatedBinary(int x, int n) {
  else return encodeToBinary(x+u, k+1);
  }
 
- private Bits encodeToBinary(int x, int len) {
+ public static Bits encodeToBinary(int x, int len) {
  Bits s = new Bits();
  while (x != 0) {
  if ((x & 0x01) == 0) s = Bits.ofZero().append(s);
@@ -91,7 +91,7 @@ public int decode(Bits bits, int m) {
  return q * m + r;
  }
 
- public int decodeTruncatedBinary(Bits bits, int m) {
+ public static int decodeTruncatedBinary(Bits bits, int m) {
  // Set k = floor(log2(n)), i.e., k such that 2^k <= n < 2^(k+1).
  int k = 0, t = m;
  while (t > 1) { k++; t >>= 1; }
@@ -101,7 +101,7 @@ public int decodeTruncatedBinary(Bits bits, int m) {
  return (x < u) ? x : (x - u);
  }
 
- private int encodeToBinary(Bits bits) {
+ public static int encodeToBinary(Bits bits) {
  int x = 0;
  for (int i = 0; i < bits.length(); i++) {
  x += (bits.get(i).value() << (bits.length() - i - 1));

src/test/java/com/github/myibu/algorithm/AlgorithmTest.java

@@ -181,6 +181,9 @@ public void testLZ77Compressor() {
  public void testGolombEncoder() {
  int m = 4;
  GolombEncoder encoder = new GolombEncoder();
+ System.out.println(encoder.encode(0, 5));
+ System.out.println(encoder.encode(1, 5));
+ System.out.println(encoder.encode(4, 5));
  List<Bits> encodeList = new ArrayList<>();
  for (int i = 1; i <= 9; i++) {
  encodeList.add(encoder.encode(i, m));