常用的字符转化的方法

1、char 转utf-8

int char2Utf8(const char *src, char **ret)
{
	int nret;
	int len = 0;
	WCHAR   *pwchar = 0;
	int codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
	len = MultiByteToWideChar(codepage, 0, src, -1, NULL, 0);
	pwchar = (WCHAR *)malloc(sizeof(WCHAR)*len);
	nret = MultiByteToWideChar(codepage, 0, src, -1, pwchar, len);
	if (nret < 0)
		return nret;

	len = WideCharToMultiByte(CP_UTF8, 0, pwchar, -1, 0, 0, 0, 0);
	*ret = (char*)malloc(len + 1);
	nret = WideCharToMultiByte(CP_UTF8, 0, pwchar, -1, *ret, len, 0, 0);
	free(pwchar);
	return nret;
}

　　2、utf-8 转 char

int Utf2char(char *src, char** ret)
{
	int nret;
	WCHAR   *pwchar = 0;
	int codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
	nret = MultiByteToWideChar(CP_UTF8, 0, src, -1, NULL, 0);
	pwchar = (WCHAR *)malloc(sizeof(WCHAR)*nret);
	nret = MultiByteToWideChar(CP_UTF8, 0, src, -1, pwchar, nret);

	nret = WideCharToMultiByte(codepage, 0, pwchar, -1, 0, 0, 0, 0);
	*ret = (char*)malloc(nret + 1);
	nret = WideCharToMultiByte(codepage, 0, pwchar, -1, *ret, nret, 0, 0);
	free(pwchar);
	return nret;

}

　　3、url 转 utf-8

string urlUtf8(char *str)
{
	string dd;
	string ascii = str;
	char utf8[BUFFER_LEN * 5];
	memset(utf8, 0x00, BUFFER_LEN * 5);
	ASCIIToUTF8_string(ascii, utf8);
	string tt = utf8;

	size_t len = tt.length();
	for (size_t i = 0; i < len; i++)
	{
		if (isalnum((BYTE)tt.at(i)))
		{
			char tempbuff[2] = { 0 };
			sprintf(tempbuff, "%c", (BYTE)tt.at(i));
			dd.append(tempbuff);
		}
		else if (isspace((BYTE)tt.at(i)))
		{
			dd.append("+");
		}
		else
		{
			char tempbuff[4];
			sprintf(tempbuff, "%%%X%X", ((BYTE)tt.at(i)) >> 4, ((BYTE)tt.at(i)) % 16);
			dd.append(tempbuff);
		}

	}
	return dd;
}

void ASCIIToUTF8_string(string &cACSII, char* cUTF8)
{
	//先将ASCII码转换为Unicode编码  
	int nlen = MultiByteToWideChar(CP_ACP, 0, cACSII.c_str(), -1, NULL, NULL);
	wchar_t *pUnicode = new wchar_t[cACSII.size() * 3];
	memset(pUnicode, 0, nlen * sizeof(wchar_t));
	MultiByteToWideChar(CP_ACP, 0, cACSII.c_str(), -1, (LPWSTR)pUnicode, nlen);
	wstring wsUnicode = pUnicode;
	//将Unicode编码转换为UTF-8编码  
	nlen = WideCharToMultiByte(CP_UTF8, 0, wsUnicode.c_str(), -1, NULL, 0, NULL, NULL);
	WideCharToMultiByte(CP_UTF8, 0, wsUnicode.c_str(), -1, cUTF8, nlen, NULL, NULL);

}

　　4、生成指定位数的随机数

std::string GetRandString(size_t size)
{
	time_t tCurTime = 0;
	int iRandValue = 0;
	int i;
	unsigned int state = 0;
	tCurTime = time(NULL);
	srand((unsigned int)tCurTime);
	char buf[255];
	for (i = 0; i < size; i++)
	{
		buf[i] = '0' + (rand() % 10);
	}

	buf[i] = '\0';
	return buf;
}

　　5、获取当前时间的时间戳

string GetTimeStamp()
{
	time_t curtime = time(NULL);
	tm *ptm = localtime(&curtime);
	char buf[64];
	sprintf(buf, "%d%02d%02d%02d%02d%02d", ptm->tm_year + 1900, ptm->tm_mon + 1,
		ptm->tm_mday, ptm->tm_hour, ptm->tm_min, ptm->tm_sec);
	return buf;

}