默认分类 – 第37页

bitfile

#include <iostream>
#include <fstream>

using namespace std;

int dump(ifstream *, bool dump = false);

int main(int ac, char** av) {
        string filename = "activeuser.bin";

        time_t t = time(NULL);

        if (ac > 1) {
                filename = string(av[1]);
        }
        ifstream in("n.txt");
        if (!in) {
                cout << "open file fail" <<endl;
        }
        cout << "count:" << dump(&in, false) <<endl;
        cout << "use time:" << time(NULL) - t << endl;

        in.close();

        return 0;
}

int dump(ifstream *in, bool dump) {
        unsigned char* ch = new unsigned char[8];
        int i = 0, j = 0, pos = 0, cnt = 0;
        char c;
        while (i < 8) {
                *(ch+i) = ('\x01' << (7 - i));
                //cout << *(ch + i) << endl;
                //printf("%d\n", *(ch+i));
                i++;
        }
        while(!in->eof()) {
                *in >> c;
                j = 0;
                while (j < 8) {
                        if ((ch[j] & c) == ch[j]) {
                                cnt++;
                                if (dump) {
                                        cout << pos * 8 + j << endl;
                                }
                        }
                        j++;
                }
                pos++;
        }
        return cnt;
}

#include <iostream>

#include <fstream>

using namespace std;

int dump(ifstream *, bool dump = false);

int main(int ac, char** av) {

string filename = "activeuser.bin";

time_t t = time(NULL);

if (ac > 1) {

filename = string(av[1]);

}

ifstream in("n.txt");

if (!in) {

cout << "open file fail" <<endl;

}

cout << "count:" << dump(&in, false) <<endl;

cout << "use time:" << time(NULL) - t << endl;

in.close();

return 0;

}

int dump(ifstream *in, bool dump) {

unsigned char* ch = new unsigned char[8];

int i = 0, j = 0, pos = 0, cnt = 0;

char c;

while (i < 8) {

*(ch+i) = ('\x01' << (7 - i));

//cout << *(ch + i) << endl;

//printf("%d\n", *(ch+i));

i++;

}

while(!in->eof()) {

*in >> c;

j = 0;

while (j < 8) {

if ((ch[j] & c) == ch[j]) {

cnt++;

if (dump) {

cout << pos * 8 + j << endl;

}

j++;

}

pos++;

}

return cnt;

}

关于sqlite的事务的使用

缘起 sqlite写入500条不大的记录居然要花费20多秒的时间，太慢了！！！分析 sqlite是一个非常优 …

继续阅读“关于sqlite的事务的使用”

PHP实现的一维关联数组序列化

下面是一个典型的k-v存储格式的PHP实现：

class db {
        public function test() {
         //.....
        }
	private function pack($arr) {
		$str = '';
		foreach($arr as $key=>$val) {
			$str .= pack("n", strlen($key)).pack("n", strlen($val)).$key.$val;
		}
		return $str;
	}
	private function unpackUserInfo($str) {
		$arrResult = array();
		$len = strlen($str);
		if ($len < 5) return $arrResult;
		$pos = 0;
		while($len - $pos >= 5) {
			$arr1 = unpack("n", substr($str, $pos, 2));
			$arr2 = unpack("n", substr($str, $pos+2, 2));

			$len_key = $arr1[1];
			$len_val = $arr2[1];
			$key = substr($str, $pos + 4, $len_key);
			$val = substr($str, $pos + 4 + $len_key, $len_val);
			$pos += 4 + $len_key + $len_val;
			$arrResult[$key] = $val;
		}
		return $arrResult;
	}

}