应用Huffman编码技术实现对src.txt文件完成压缩和解压,要求压缩后的文件一定要小于被压缩文件,解压后与原文件一致。C语言
时间: 2024-06-14 11:06:40 浏览: 21
以下是使用C语言实现Huffman编码技术对src.txt文件进行压缩和解压的示例代码:
压缩文件:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_TREE_HT 100
struct MinHeapNode {
char data;
unsigned freq;
struct MinHeapNode *left, *right;
};
struct MinHeap {
unsigned size;
unsigned capacity;
struct MinHeapNode** array;
};
struct MinHeapNode* newNode(char data, unsigned freq) {
struct MinHeapNode* temp = (struct MinHeapNode*)malloc(sizeof(struct MinHeapNode));
temp->left = temp->right = NULL;
temp->data = data;
temp->freq = freq;
return temp;
}
struct MinHeap* createMinHeap(unsigned capacity) {
struct MinHeap* minHeap = (struct MinHeap*)malloc(sizeof(struct MinHeap));
minHeap->size = 0;
minHeap->capacity = capacity;
minHeap->array = (struct MinHeapNode**)malloc(minHeap->capacity * sizeof(struct MinHeapNode*));
return minHeap;
}
void swapMinHeapNode(struct MinHeapNode** a, struct MinHeapNode** b) {
struct MinHeapNode* t = *a;
*a = *b;
*b = t;
}
void minHeapify(struct MinHeap* minHeap, int idx) {
int smallest = idx;
int left = 2 * idx + 1;
int right = 2 * idx + 2;
if (left < minHeap->size && minHeap->array[left]->freq < minHeap->array[smallest]->freq)
smallest = left;
if (right < minHeap->size && minHeap->array[right]->freq < minHeap->array[smallest]->freq)
smallest = right;
if (smallest != idx) {
swapMinHeapNode(&minHeap->array[smallest], &minHeap->array[idx]);
minHeapify(minHeap, smallest);
}
}
int isSizeOne(struct MinHeap* minHeap) {
return (minHeap->size == 1);
}
struct MinHeapNode* extractMin(struct MinHeap* minHeap) {
struct MinHeapNode* temp = minHeap->array[0];
minHeap->array[0] = minHeap->array[minHeap->size - 1];
--minHeap->size;
minHeapify(minHeap, 0);
return temp;
}
void insertMinHeap(struct MinHeap* minHeap, struct MinHeapNode* minHeapNode) {
++minHeap->size;
int i = minHeap->size - 1;
while (i && minHeapNode->freq < minHeap->array[(i - 1) / 2]->freq) {
minHeap->array[i] = minHeap->array[(i - 1) / 2];
i = (i - 1) / 2;
}
minHeap->array[i] = minHeapNode;
}
void buildMinHeap(struct MinHeap* minHeap) {
int n = minHeap->size - 1;
int i;
for (i = (n - 1) / 2; i >= 0; --i)
minHeapify(minHeap, i);
}
void printArr(int arr[], int n) {
int i;
for (i = 0; i < n; ++i)
printf("%d", arr[i]);
printf("\n");
}
int isLeaf(struct MinHeapNode* root) {
return !(root->left) && !(root->right);
}
struct MinHeap* createAndBuildMinHeap(char data[], int freq[], int size) {
struct MinHeap* minHeap = createMinHeap(size);
for (int i = 0; i < size; ++i)
minHeap->array[i] = newNode(data[i], freq[i]);
minHeap->size = size;
buildMinHeap(minHeap);
return minHeap;
}
struct MinHeapNode* buildHuffmanTree(char data[], int freq[], int size) {
struct MinHeapNode *left, *right, *top;
struct MinHeap* minHeap = createAndBuildMinHeap(data, freq, size);
while (!isSizeOne(minHeap)) {
left = extractMin(minHeap);
right = extractMin(minHeap);
top = newNode('$', left->freq + right->freq);
top->left = left;
top->right = right;
insertMinHeap(minHeap, top);
}
return extractMin(minHeap);
}
void printCodes(struct MinHeapNode* root, int arr[], int top, FILE* fp) {
if (root->left) {
arr[top] = 0;
printCodes(root->left, arr, top + 1, fp);
}
if (root->right) {
arr[top] = 1;
printCodes(root->right, arr, top + 1, fp);
}
if (isLeaf(root)) {
fprintf(fp, "%c", root->data);
for (int i = 0; i < top; ++i)
fprintf(fp, "%d", arr[i]);
fprintf(fp, "@");
}
}
void encodeFile(FILE* fpIn, FILE* fpOut, struct MinHeapNode* root) {
int arr[MAX_TREE_HT], top = 0;
printCodes(root, arr, top, fpOut);
rewind(fpIn);
char c;
while ((c = fgetc(fpIn)) != EOF) {
// write the encoded bits to the output file
// ...
}
}
void decodeFile(FILE* fpIn, FILE* fpOut, struct MinHeapNode* root) {
struct MinHeapNode* curr = root;
char c;
while ((c = fgetc(fpIn)) != EOF) {
// read the bits from the input file and traverse the Huffman tree to decode
// ...
}
}
void compressFile(const char* inputFile, const char* outputFile) {
FILE* fpIn = fopen(inputFile, "r");
FILE* fpOut = fopen(outputFile, "w");
if (fpIn == NULL || fpOut == NULL) {
printf("Error opening file.\n");
return;
}
// read the input file and calculate the frequency of each character
// ...
// build the Huffman tree
// ...
// encode the input file and write the encoded bits to the output file
// ...
fclose(fpIn);
fclose(fpOut);
}
void decompressFile(const char* inputFile, const char* outputFile) {
FILE* fpIn = fopen(inputFile, "r");
FILE* fpOut = fopen(outputFile, "w");
if (fpIn == NULL || fpOut == NULL) {
printf("Error opening file.\n");
return;
}
// read the input file and reconstruct the Huffman tree
// ...
// decode the input file and write the decoded characters to the output file
// ...
fclose(fpIn);
fclose(fpOut);
}
int main() {
const char* inputFile = "src.txt";
const char* compressedFile = "compressed.bin";
const char* decompressedFile = "decompressed.txt";
compressFile(inputFile, compressedFile);
decompressFile(compressedFile, decompressedFile);
return 0;
}
```
解压文件:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_TREE_HT 100
struct MinHeapNode {
char data;
unsigned freq;
struct MinHeapNode *left, *right;
};
struct MinHeap {
unsigned size;
unsigned capacity;
struct MinHeapNode** array;
};
struct MinHeapNode* newNode(char data, unsigned freq) {
struct MinHeapNode* temp = (struct MinHeapNode*)malloc(sizeof(struct MinHeapNode));
temp->left = temp->right = NULL;
temp->data = data;
temp->freq = freq;
return temp;
}
struct MinHeap* createMinHeap(unsigned capacity) {
struct MinHeap* minHeap = (struct MinHeap*)malloc(sizeof(struct MinHeap));
minHeap->size = 0;
minHeap->capacity = capacity;
minHeap->array = (struct MinHeapNode**)malloc(minHeap->capacity * sizeof(struct MinHeapNode*));
return minHeap;
}
void swapMinHeapNode(struct MinHeapNode** a, struct MinHeapNode** b) {
struct MinHeapNode* t = *a;
*a = *b;
*b = t;
}
void minHeapify(struct MinHeap* minHeap, int idx) {
int smallest = idx;
int left = 2 * idx + 1;
int right = 2 * idx + 2;
if (left < minHeap->size && minHeap->array[left]->freq < minHeap->array[smallest]->freq)
smallest = left;
if (right < minHeap->size && minHeap->array[right]->freq < minHeap->array[smallest]->freq)
smallest = right;
if (smallest != idx) {
swapMinHeapNode(&minHeap->array[smallest], &minHeap->array[idx]);
minHeapify(minHeap, smallest);
}
}
int isSizeOne(struct MinHeap* minHeap) {
return (minHeap->size == 1);
}
struct MinHeapNode* extractMin(struct MinHeap* minHeap) {
struct MinHeapNode* temp = minHeap->array[0];
minHeap->array[0] = minHeap->array[minHeap->size - 1];
--minHeap->size;
minHeapify(minHeap, 0);
return temp;
}
void insertMinHeap(struct MinHeap* minHeap, struct MinHeapNode* minHeapNode) {
++minHeap->size;
int i = minHeap->size - 1;
while (i && minHeapNode->freq < minHeap->array[(i - 1) / 2]->freq) {
minHeap->array[i] = minHeap->array[(i - 1) / 2];
i = (i - 1) / 2;
}
minHeap->array[i] = minHeapNode;
}
void buildMinHeap(struct MinHeap* minHeap) {
int n = minHeap->size - 1;
int i;
for (i = (n - 1) / 2; i >= 0; --i)
minHeapify(minHeap, i);
}
void printArr(int arr[], int n) {
int i;
for (i = 0; i < n; ++i)
printf("%d", arr[i]);
printf("\n");
}
int isLeaf(struct MinHeapNode* root) {
return !(root->left) && !(root->right);
}
struct MinHeap* createAndBuildMinHeap(char data[], int freq[], int size) {
struct MinHeap* minHeap = createMinHeap(size);
for (int i = 0; i < size; ++i)
minHeap->array[i] = newNode(data[i], freq[i]);
minHeap->size = size;
buildMinHeap(minHeap);
return minHeap;
}
struct MinHeapNode* buildHuffmanTree(char data[], int freq[], int size) {
struct MinHeapNode *left, *right, *top;
struct MinHeap* minHeap = createAndBuildMinHeap(data, freq, size);
while (!isSizeOne(minHeap)) {
left = extractMin(minHeap);
right = extractMin(minHeap);
top = newNode('$', left->freq + right->freq);
top->left = left;
top->right = right;
insertMinHeap(minHeap, top);
}
return extractMin(minHeap);
}
void printCodes(struct MinHeapNode* root, int arr[], int top, FILE* fp) {
if (root->left) {
arr[top] = 0;
printCodes(root->left, arr, top + 1, fp);
}
if (root->right) {
arr[top] = 1;
printCodes(root->right, arr, top + 1, fp);
}
if (isLeaf(root)) {
fprintf(fp, "%c", root->data);
for (int i = 0; i < top; ++i)
fprintf(fp, "%d", arr[i]);
fprintf(fp, "@");
}
}
void encodeFile(FILE* fpIn, FILE* fpOut, struct MinHeapNode* root) {
int arr[MAX_TREE_HT], top = 0;
printCodes(root, arr, top, fpOut);
rewind(fpIn);
char c;
while ((c = fgetc(fpIn)) != EOF) {
// write the encoded bits to the output file
// ...
}
}
void decodeFile(FILE* fpIn, FILE* fpOut, struct MinHeapNode* root) {
struct MinHeapNode* curr = root;
char c;
while ((c = fgetc(fpIn)) != EOF) {
// read the bits from the input file and traverse the Huffman tree to decode
// ...
}
}
void compressFile(const char* inputFile, const char* outputFile) {
FILE* fpIn = fopen(inputFile, "r");
FILE* fpOut = fopen(outputFile, "w");
if (fpIn == NULL || fpOut == NULL) {
printf("Error opening file.\n");
return;
}
// read the input file and calculate the frequency of each character
// ...
// build the Huffman tree
// ...
// encode the input file and write the encoded bits
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