哈夫曼压缩&大球吃小球

哈夫曼压缩/src/哈夫曼/Compare.java

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+package ¹þ·òÂü;
+
+import java.util.Comparator;
+
+public class Compare implements Comparator<HufTree>{
+
+    @Override
+    public int compare(HufTree o1, HufTree o2) {
+        if(o1.weight < o2.weight)
+            return -1;
+        else if(o1.weight > o2.weight)
+            return 1;
+        return 0;
+    }
+
+}

哈夫曼压缩/src/哈夫曼/HufTree.java

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+package 哈夫曼;
+
+public class HufTree{
+    public byte Byte; //以8位为单元的字节
+    public int weight;//该字节在文件中出现的次数
+    public String code; //对应的哈夫曼编码
+    public HufTree lchild,rchild;
+
+    /**调试的时候添加的**/
+    public String toString(){
+        return "Byte:" + Byte + ",weight:" + weight + ",code:" + code + ",+ lchild:" + lchild + ",rchild:" + rchild;
+    }
+}
+
+//统计字符频度的临时节点
+class TmpNode implements Comparable<TmpNode>{
+    public byte Byte;
+    public int weight;
+
+    @Override
+    public int compareTo(TmpNode arg0) {
+        if(this.weight < arg0.weight)
+            return 1;
+        else if(this.weight > arg0.weight)
+            return -1;
+        return 0;
+    }
+}

哈夫曼压缩/src/哈夫曼/HuffmanCompress.java

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+package 哈夫曼;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.PriorityQueue;
+
+public class HuffmanCompress {
+	private PriorityQueue<HufTree> queue = null;
+
+	public void compress(File inputFile, File outputFile) {
+		Compare cmp = new Compare();
+		queue = new PriorityQueue<HufTree>(12, cmp);
+
+		// 映射字节及其对应的哈夫曼编码
+		HashMap<Byte, String> map = new HashMap<Byte, String>();
+
+		int i, char_kinds = 0;
+		int char_tmp, file_len = 0;
+		FileInputStream fis = null;
+		FileOutputStream fos = null;
+		DataOutputStream oos = null;
+
+		HufTree root = new HufTree();
+		String code_buf = null;
+
+		// 临时储存字符频度的数组
+		TmpNode[] tmp_nodes = new TmpNode[256];
+
+		for (i = 0; i < 256; i++) {
+			tmp_nodes[i] = new TmpNode();
+			tmp_nodes[i].weight = 0;
+			tmp_nodes[i].Byte = (byte) i;
+		}
+
+		try {
+			fis = new FileInputStream(inputFile);
+			fos = new FileOutputStream(outputFile);
+			oos = new DataOutputStream(fos);
+
+			/*
+			 * 统计字符频度，计算文件长度
+			 */
+			while ((char_tmp = fis.read()) != -1) {
+				tmp_nodes[char_tmp].weight++;
+				file_len++;
+			}
+			fis.close();
+			// 排序，将频度为0的字节放在最后，同时计算除字节的种类，即有多少个不同的字节
+			Arrays.sort(tmp_nodes);
+			for (i = 0; i < 256; i++) {
+				if (tmp_nodes[i].weight == 0) {
+					break;
+				}
+				HufTree tmp = new HufTree();
+				tmp.Byte = tmp_nodes[i].Byte;
+				tmp.weight = tmp_nodes[i].weight;
+				queue.add(tmp);
+			}
+			char_kinds = i;
+
+			if (char_kinds == 1) {
+				oos.writeInt(char_kinds);
+				oos.writeByte(tmp_nodes[0].Byte);
+				oos.writeInt(tmp_nodes[0].weight);
+			} else {
+				// 建树
+				createTree(queue);
+				root = queue.peek();
+				// 生成哈夫曼编码
+				hufCode(root, "", map);
+				// 写入字节种类
+				oos.writeInt(char_kinds);
+				for (i = 0; i < char_kinds; i++) {
+					oos.writeByte(tmp_nodes[i].Byte);
+					oos.writeInt(tmp_nodes[i].weight);
+				}
+				oos.writeInt(file_len);
+				fis = new FileInputStream(inputFile);
+				code_buf = "";
+				while ((char_tmp = fis.read()) != -1) {
+					code_buf += map.get((byte) char_tmp);
+					while (code_buf.length() >= 8) {
+						char_tmp = 0;
+						for (i = 0; i < 8; i++) {
+							char_tmp <<= 1;
+							if (code_buf.charAt(i) == '1')
+								char_tmp |= 1;
+						}
+						oos.writeByte((byte) char_tmp);
+						code_buf = code_buf.substring(8);
+					}
+				}
+				// 最后编码长度不够8位的时候，用0补齐
+				if (code_buf.length() > 0) {
+					char_tmp = 0;
+					for (i = 0; i < code_buf.length(); ++i) {
+						char_tmp <<= 1;
+						if (code_buf.charAt(i) == '1')
+							char_tmp |= 1;
+					}
+					char_tmp <<= (8 - code_buf.length());
+					oos.writeByte((byte) char_tmp);
+				}
+				oos.close();
+				fis.close();
+			}
+
+		} catch (Exception e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+	}
+
+	public void extract(File inputFile, File outputFile) {
+		Compare cmp = new Compare();
+		queue = new PriorityQueue<HufTree>(12, cmp);
+
+		int i;
+		int file_len = 0;
+		int writen_len = 0;
+		FileInputStream fis = null;
+		FileOutputStream fos = null;
+		DataInputStream ois = null;
+
+		int char_kinds = 0;
+		HufTree root=new HufTree();
+		byte code_tmp;
+		try {
+			fis = new FileInputStream(inputFile);
+			ois = new DataInputStream(fis);
+			fos = new FileOutputStream(outputFile);
+
+			char_kinds = ois.readInt();
+			// 字节只有一种
+			if (char_kinds == 1) {
+				code_tmp = ois.readByte();
+				file_len = ois.readInt();
+				while ((file_len--) != 0) {
+					fos.write(code_tmp);
+				}
+			} else {
+				for (i = 0; i < char_kinds; i++) {
+					HufTree tmp = new HufTree();
+					tmp.Byte = ois.readByte();
+					tmp.weight = ois.readInt();
+					System.out.println("Byte: "+tmp.Byte+" weight: "+tmp.weight);
+					queue.add(tmp);
+				}
+
+				createTree(queue);
+
+				file_len = ois.readInt();
+				root = queue.peek();
+				while (true) {
+					code_tmp = ois.readByte();
+					for (i = 0; i < 8; i++) {
+						if ((code_tmp&128)==128) {
+							root = root.rchild;
+						} else {
+							root = root.lchild;
+						}
+						if (root.lchild == null && root.rchild == null) {
+							fos.write(root.Byte);
+							++writen_len;
+							if (writen_len == file_len)
+								break;
+							root = queue.peek();
+						}
+						code_tmp <<= 1;
+					}
+					if (writen_len == file_len)
+						break;
+				}
+			}
+			fis.close();
+			fos.close();
+
+		} catch (Exception e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+
+	}
+
+	public void createTree(PriorityQueue<HufTree> queue) {
+		while (queue.size() > 1) {
+			HufTree min1 = queue.poll();
+			HufTree min2 = queue.poll();
+			System.out.print(min1.weight + " " + min2.weight + " ");
+
+			HufTree NodeParent = new HufTree();
+			NodeParent.weight = min1.weight + min2.weight;
+			NodeParent.lchild = min1;
+			NodeParent.rchild = min2;
+
+			queue.add(NodeParent);
+		}
+	}
+
+	public void hufCode(HufTree root, String s, HashMap<Byte, String> map) {
+		if (root.lchild == null && root.rchild == null) {
+			root.code = s;
+			System.out.println("节点" + root.Byte + "编码" + s);
+			map.put(root.Byte, root.code);
+
+			return;
+		}
+		if (root.lchild != null) {
+			hufCode(root.lchild, s + '0', map);
+		}
+		if (root.rchild != null) {
+			hufCode(root.rchild, s + '1', map);
+		}
+
+	}
+
+}

哈夫曼压缩/src/哈夫曼/test.java

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+package 哈夫曼;
+
+import java.io.File;
+
+public class test {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		HuffmanCompress sample = new HuffmanCompress();
+	//	File inputFile = new File("C:\\Users\\long452a\\Desktop\\opencv链接文档.txt");
+	//   File outputFile = new File("C:\\Users\\long452a\\Desktop\\opencv链接文档.rar");
+	//    sample.compress(inputFile, outputFile);
+	    File inputFile = new File("C:\\Users\\long452a\\Desktop\\opencv链接文档.rar");
+	        File outputFile = new File("C:\\Users\\long452a\\Desktop\\opencv链接文档1.txt");
+	       sample.extract(inputFile, outputFile);
+	}
+
+}