帮我写一个C语言数据解压的程序,分别用LZ77、LZ78、Huffman这三方法
时间: 2023-05-22 22:00:48 浏览: 72
来实现。以下是示例代码:
LZ77解压:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_BUFFER_SIZE 1024
typedef struct {
int offset;
int length;
char next_char;
} lz77_token;
void lz77_decompress(char* compressed_data, char* decompressed_data) {
int compressed_data_length = strlen(compressed_data);
int decompressed_data_length = 0;
int i = 0;
while (i < compressed_data_length) {
lz77_token token;
memcpy(&token, compressed_data + i, sizeof(lz77_token));
i += sizeof(lz77_token);
if (token.length == 0) {
decompressed_data[decompressed_data_length++] = token.next_char;
} else {
int j;
for (j = 0; j < token.length; j++) {
decompressed_data[decompressed_data_length + j] = decompressed_data[decompressed_data_length - token.offset + j];
}
decompressed_data_length += token.length;
decompressed_data[decompressed_data_length++] = token.next_char;
}
}
decompressed_data[decompressed_data_length] = '\0';
}
LZ78解压:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_BUFFER_SIZE 1024
typedef struct {
int prefix_index;
char next_char;
} lz78_token;
void lz78_decompress(char* compressed_data, char* decompressed_data) {
int compressed_data_length = strlen(compressed_data);
int decompressed_data_length = 0;
int i = 0;
int dict_size = 0;
char** dictionary = (char**)malloc(MAX_BUFFER_SIZE * sizeof(char*));
memset(dictionary, 0, MAX_BUFFER_SIZE * sizeof(char*));
while (i < compressed_data_length) {
lz78_token token;
memcpy(&token, compressed_data + i, sizeof(lz78_token));
i += sizeof(lz78_token);
if (token.prefix_index == 0) {
decompressed_data[decompressed_data_length++] = token.next_char;
dictionary[++dict_size] = strdup(&decompressed_data[decompressed_data_length - 1]);
} else {
char* new_string = (char*)malloc(MAX_BUFFER_SIZE * sizeof(char));
strcpy(new_string, dictionary[token.prefix_index]);
new_string[strlen(new_string)] = token.next_char;
decompressed_data_length += strlen(new_string);
strcpy(&decompressed_data[decompressed_data_length - strlen(new_string)], new_string);
dictionary[++dict_size] = strdup(new_string);
free(new_string);
}
}
decompressed_data[decompressed_data_length] = '\0';
int j;
for (j = 1; j <= dict_size; j++) {
free(dictionary[j]);
}
free(dictionary);
}
Huffman解压:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_BUFFER_SIZE 1024
typedef struct {
char character;
char* code;
} huffman_node;
void huffman_decompress(char* compressed_data, char* decompressed_data) {
int compressed_data_length = strlen(compressed_data);
int decompressed_data_length = 0;
int i = 0;
huffman_node* huffman_tree = (huffman_node*)malloc(MAX_BUFFER_SIZE * sizeof(huffman_node));
memset(huffman_tree, 0, MAX_BUFFER_SIZE * sizeof(huffman_node));
while (i < compressed_data_length) {
char character = compressed_data[i++];
char* code = (char*)malloc(MAX_BUFFER_SIZE * sizeof(char));
memset(code, 0, MAX_BUFFER_SIZE * sizeof(char));
int j = 0;
while (compressed_data[i] != '\0') {
code[j++] = compressed_data[i++];
if (huffman_tree[character].code != NULL) {
break;
}
}
huffman_tree[character].character = character;
huffman_tree[character].code = strdup(code);
free(code);
}
char* code = (char*)malloc(MAX_BUFFER_SIZE * sizeof(char));
memset(code, 0, MAX_BUFFER_SIZE * sizeof(char));
i++;
while (i < compressed_data_length) {
code[strlen(code)] = compressed_data[i++];
int j;
for (j = 0; j < 256; j++) {
if (huffman_tree[j].code != NULL && strcmp(huffman_tree[j].code, code) == 0) {
decompressed_data[decompressed_data_length++] = huffman_tree[j].character;
memset(code, 0, MAX_BUFFER_SIZE * sizeof(char));
break;
}
}
}
decompressed_data[decompressed_data_length] = '\0';
int j;
for (j = 0; j < 256; j++) {
if (huffman_tree[j].code != NULL) {
free(huffman_tree[j].code);
}
}
free(huffman_tree);
}