文本压缩

来源：互联网发布：java中冒泡排序法代码编辑：程序博客网时间：2024/05/21 06:59
程序有问题，暂时做个记录，以后会修改
#include <stdio.h>#include <stdlib.h>#include <assert.h>#include <string.h>const int SIZE = 256;void tong_ji_ping_du(FILE *f, int ping_du[]) {    int c;    while ((c=fgetc(f)) != EOF) {        ++ping_du[c];    }}struct Huffman_Node {    int key;    Huffman_Node *parent, *lChild, *rChild;};void Select_Node(Huffman_Node *tree, Huffman_Node **s1, Huffman_Node **s2, int n) {    *s1 = *s2 = NULL;    for (int i=0; i<n; ++i) {        if (tree[i].key!=0 && tree[i].parent==NULL && (*s1==NULL || tree[i].key< (*s1)->key)) {            *s2 = *s1;            *s1 = &tree[i];        }        else if (tree[i].key!=0 && tree[i].parent==NULL && (*s2==NULL || tree[i].key < (*s2)->key)) {            *s2 = &tree[i];        }    }}void Huffman_code(int ping_du[], char codes[][SIZE+1]) {    Huffman_Node *tree;    Huffman_Node *s1;    Huffman_Node *s2;    int m = 2 * SIZE - 1;    tree = new Huffman_Node[m];    memset(tree, 0, sizeof(Huffman_Node) * m);    m = SIZE;    for (int i=0; i<SIZE; ++i) {        if (ping_du[i] != 0) ++m;        tree[i].key = ping_du[i];    }    for (int i=SIZE; i<m-1; ++i) {        Select_Node(tree, &s1, &s2, i);        assert(s1!=NULL && s2!=NULL);        tree[i].key = s1->key + s2->key;        s1->parent = &tree[i];        s2->parent = &tree[i];        tree[i].lChild = s1;        tree[i].rChild = s2;    }    char code[SIZE+1];    int start;    Huffman_Node *node;    for (int i=0; i<SIZE; ++i) {        if (ping_du[i]==0) continue;        memset(code, 0, SIZE+1);        start = SIZE;        node = &tree[i];        while (node->parent!=NULL) {            if (node->parent->lChild==node) code[--start] = '0';            else code[--start] = '1';            node = node->parent;        }        strcpy(&codes[i][0], &code[start]);    }}void ya_suo(FILE *f, FILE *f2, int ping_du[], char codes[][SIZE+1]) {    size_t f_size = 0;    // 计算文件大小    for (int i=0; i<SIZE; ++i) {        f_size += ping_du[i];    }    // 写入HEAD信息    fprintf(f2, "HEAD BEGIN\n");    fprintf(f2, "file_size:%lu\n", f_size);    for (int i=0; i<SIZE; ++i) {        if (ping_du[i] == 0) continue;        fprintf(f2, "%d:%s\n", i, codes[i]);    }    fprintf(f2, "HEAD END\n");    int c;    char cByte;    int byte_size = 0;    while ((c=fgetc(f)) != EOF) {        for (int i=0; i<strlen(&codes[c][0]); ++i) {            ++byte_size;            cByte >>= 1;            cByte &= 0x7F; // 最高位设置为0            if (codes[c][i] == '1') cByte ^= 0x80;            if (byte_size == 8) {                byte_size = 0;                fputc(cByte, f2);            }        }    }    for (int i=byte_size; i<8; ++i) {        cByte >>= 1;    }    fputc(cByte, f2);}void jie_ya(FILE *f, FILE *f2) {    char codes[SIZE][SIZE+1] = {0};    char buf[BUFSIZ];    int ch;    char code[SIZE+1] = {0};    size_t f_size;    fgets(buf, BUFSIZ, f2);    buf[strlen(buf)-1] = '\0';    if (strcmp(buf, "HEAD BEGIN") == 0) {        fgets(buf, BUFSIZ, f2);        buf[strlen(buf)-1] = '\0';        sscanf(buf, "file_size:%ld", &f_size);        fgets(buf, BUFSIZ, f2);        buf[strlen(buf)-1] = '\0';        while (strcmp(buf, "HEAD END")!=0) {            sscanf(buf, "%d:%s", &ch, code);            strcpy(&codes[ch][0], code);            fgets(buf, BUFSIZ, f2);            buf[strlen(buf)-1] = '\0';        }    }    memset(code, 0, SIZE+1);    int i_ch = 0;    while (f_size>0 && (ch=fgetc(f2))!=EOF) {        for (int i=0; i<8; ++i) {            code[i_ch++] = (ch & 0x1) + '0';            ch >>= 1;            for (int j=0; j<SIZE; ++j) {                if (strcmp(&codes[j][0], code) == 0) {                    if (f_size>0)                        fputc(j, f);                    --f_size;                    i_ch = 0;                    memset(code, 0, SIZE+1);                    break;                }            }        }    }}int main(int argc, char *argv[]) {    assert(argc==4);    int cmd = atoi(argv[1]);    char *f_name = argv[2];    char *f_name2 = argv[3];    if (cmd==1) {        FILE *f = fopen(f_name, "rb");        FILE *f2 = fopen(f_name2, "wb");        int ping_du[SIZE]={0};        char codes[SIZE][SIZE+1]={0};        // 统计字节的频率        tong_ji_ping_du(f, ping_du);        // 生成huffman编码        Huffman_code(ping_du, codes);        rewind(f);        ya_suo(f, f2, ping_du, codes);        fclose(f);        fclose(f2);    }    else if (cmd==2) {        FILE *f = fopen(f_name2, "wb");        FILE *f2 = fopen(f_name, "rb");        jie_ya(f, f2);        fclose(f);        fclose(f2);    }    return 0;}
0 0