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| #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <map>
#include <queue>
#include <cassert>
#include <cstring>
using namespace std;
typedef unsigned int u_int;
struct Node {
char key;
u_int freq;
Node *self;
Node *left, *right;
Node() { left = right = 0; key = 0; self = this;}
bool operator<(const Node & _n) const {
return freq > _n.freq ? true : freq < _n.freq ? false : key < _n.key ? true : false;
}
};
const u_int BLOCK_SIZE = 1024;
class Huffman {
public:
Node *buildTree() {
priority_queue<Node> Q;
u_int num = 0;
for(u_int i = 0; i < 256; ++i) {
if(counter[i] == 0) continue;
Node *ans = new Node();
ans->key = i, ans->freq = counter[i], ans->self = ans;
//fprintf(stderr, "%d - %d\n", ans->key, ans->freq);
Q.push(*ans);
++num;
}
for(int i = 1; i < num; ++i) {
assert(!Q.empty());
Node first = Q.top(); Q.pop();
assert(!Q.empty());
Node second = Q.top(); Q.pop();
//fprintf(stderr, "(%d - %d)\n", first.freq, second.freq);
Node *ans = new Node();
ans->left = first.self, ans->right = second.self;
ans->freq = first.freq + second.freq;
Q.push(*ans);
}
assert(!Q.empty());
return Q.top().self;
}
void trace(char *_code, u_int depth, const Node * _node) {
if(_node->left == NULL && _node->right == NULL) {
fprintf(stderr, "key: %d\tdepth: %d\tcode: ", _node->key, depth);
for(int i = 0; i < depth; i++)
fprintf(stderr, "%d", *(_code - depth + i));
fprintf(stderr, "\n");
return;
}
if(_node->left) {
//fprintf(stderr, "(");
*_code = 0;
trace(_code+1, depth + 1, _node->left);
*_code = 2;
}
if(_node->right) {
*_code = 1;
trace(_code+1, depth+1, _node->right);
*_code = 2;
//fprintf(stderr, ")");
}
}
void readFile(const char *file) {
FILE *fin = fopen(file, "rb");
if(fin== NULL) {
fprintf(stderr, "fopen fail.\n");
exit(-1);
}
char str[BLOCK_SIZE];
u_int n;
memset(counter, 0, sizeof(counter));
while((n = fread(str, sizeof(char), BLOCK_SIZE, fin)) > 0)
for(u_int i = 0; i < n; ++i) counter[(int)str[i]]++;
//for(int i = 0; i < 256; ++i) fprintf(stderr, "counter[%d]: %d\n", i, counter[i]);
fclose(fin);
}
void compress(const char *file, const char *outFile) {
readFile(file);
Node *root = buildTree();
char _code[256];
//trace(_code, 0, root);
encode(_code, 0, root);
writeFile(file, outFile);
}
void i2ch(u_int n, char *str) {
for(int i = 0; i < 4; ++i) {
*(str+i) = 0xff & (n >> ((3-i)*8));
}
}
void writeFile(const char *file, const char *com) {
FILE *fin = fopen(file, "rb");
FILE *fout = fopen(com, "wb");
if(fin== NULL || fout == NULL) {
fprintf(stderr, "fopen fail.\n");
exit(-1);
}
u_int num = 0;
for(int i = 0; i < 256; ++i) if(counter[i] > 0) num++;
char ntr[8] = {0};
i2ch(num, ntr);
//fprintf(stderr, "num : %d-%d-%d-%d - %u \n", ntr[0], ntr[1], ntr[2], ntr[3], num);
if(fwrite(ntr, sizeof(char), 4, fout) < 4) {
fprintf(stderr, "fwrite 4 error.\n");
exit(-1);
}
for(int i = 0; i < 256; ++i) {
if(counter[i] == 0) continue;
char ttr[8] = {0};
ttr[0] = i;
i2ch(counter[i], ttr+1);
if(fwrite(ttr, sizeof(char), 5, fout) < 5) {
fprintf(stderr, "fwrite 5 error.\n");
exit(-1);
}
}
char str[BLOCK_SIZE];
char ctr[BLOCK_SIZE];
memset(ctr, 0, sizeof(ctr));
u_int n, ex = 0;
int ix = 7;
while((n = fread(str, sizeof(char), BLOCK_SIZE, fin)) > 0) {
for(u_int i = 0; i < n; ++i) {
for(int j = 0; j < mask[str[i]]; ++j) {
if(code[str[i]][j] == 1)
ctr[ex] = ctr[ex] | (1<<ix);
ix--;
if(ix < 0) ex++, ix = 7;
if(ex == BLOCK_SIZE) {
//写入文件
if(fwrite(ctr, sizeof(char), ex, fout) < ex) {
fprintf(stderr, "fwrite error.\n");
exit(-1);
}
memset(ctr, 0, sizeof(ctr));
ex = 0, ix = 7;
}
}
}
}
//fprintf(stderr, "write in to compress ex %d\n", ex);
if(fwrite(ctr, sizeof(char), ex, fout) < ex) {
fprintf(stderr, "fwrite error.\n");
exit(-1);
}
fclose(fin);
fclose(fout);
}
void binaryPrint(char n) {
for(int i = 7; i >= 0; --i)
fprintf(stderr, "%d", ((1<<i) & (0x000000ff & n)) ? 1 : 0);
}
//_code : 0, _mask : 0
void encode(char *_code, char _mask, const Node *node) {
if(node->left == NULL && node->right == NULL) {
for(int i = 0; i < _mask; ++i) {
code[node->key][i] = *(_code-_mask+i);
}
mask[node->key] = _mask;
return ;
}
if(node->left) {
*_code = 0;
encode(_code+1, _mask+1, node->left);
}
if(node->right) {
*_code = 1;
encode(_code+1, _mask+1, node->right);
}
}
void decompress(const char *file, const char *outFile) {
FILE *fin = fopen(file, "rb");
FILE *fout = fopen(outFile, "wb");
if(fin == NULL || fout == NULL) {
fprintf(stderr, "fopen fail.\n");
exit(-1);
}
char str[BLOCK_SIZE] = {0};
memset(counter, 0, sizeof(counter));
if(fread(str, sizeof(char), 4, fin) < 4) {
fprintf(stderr, "fread first 4 char fail.\n");
exit(-1);
}
u_int n = ch2i(str);
//fprintf(stderr, "n : %d-%d-%d-%d - %u \n", str[0], str[1], str[2], str[3], n);
for(u_int i = 0; i < n; ++i) {
if(fread(str, sizeof(char), 5, fin) < 5) {
fprintf(stderr, "fread 5-group fail.\n");
exit(-1);
}
counter[(int)str[0]] = ch2i(str+1);
}
Node *root = buildTree();
Node *ans = root;
char _code[256];
//trace(_code, 0, ans);
u_int ix = 0;
char ctr[BLOCK_SIZE];
while((n = fread(str, sizeof(char), BLOCK_SIZE, fin)) > 0) {
for(u_int i = 0; i < n; ++i) {
for(int j = 7; j >= 0; --j) {
//fprintf(stderr, "%d",((1<<j) & (0x000000ff & str[i])) ? 1 : 0);
if(((1<<j) & (0x000000ff & str[i]))) {
assert(ans->right != NULL);
ans = ans->right;
}
else {
assert(ans->left != NULL);
ans = ans->left;
}
if(ans->left == NULL && ans->right == NULL) {
//fprintf(stderr, "\n");
ctr[ix++] = ans->key;
if(ix == BLOCK_SIZE) {
//写入文件
fwrite(ctr, sizeof(char), ix, fout);
ix = 0;
}
ans = root;
}
}
}
}
fwrite(ctr, sizeof(char), ix, fout);
fclose(fin);
fclose(fout);
}
u_int ch2i(const char *str) {
u_int res = 0;
for(int i = 0; i < 4; ++i) res = (res<<8) | (0x000000ff & str[i]);
return res;
}
private:
char mask[256];
char code[256][256];
u_int counter[256];
};
int
main(int argc, char **argv) {
Huffman huff;
// huffman -c compress compressed
// huffman -d decompress decompressed
if(argc < 4) {
fprintf(stderr, "usage: huffman -cd file.in file.out\n");
exit(-1);
}
if(strcmp(argv[1], "-c") == 0) {
huff.compress(argv[2], argv[3]);
}
else if(strcmp(argv[1], "-d") == 0) {
huff.decompress(argv[2], argv[3]);
}
else {
fprintf(stderr, "usage: option -c or -d.\n");
exit(-1);
}
return 0;
} |
