URL Encoding

URL-encodes string. This algorithm is convenient when encoding a string to be used in a query part of a URL, as a convenient way to pass variables to the next page.

• C#
• VB.Net
• C
• C++
• PHP

									char* DecimalToHexadecimal(int dec)
{
	if (dec < 1) return "0";

	int hex = dec;
	char hexStr[8];
	int i = 0;
	char temp;

	while (dec > 0)
	{
		hex = dec % 16;

		if (hex < 10) {
			temp = (char)(hex + 48);
		}
		else {
			temp = (char)(hex + 55);
		}

		hexStr[i++] = temp;
		dec /= 16;
	}

	for (int j = 0; j < i - 1; j++)
	{
		temp = hexStr[j];
		hexStr[j] = hexStr[(i - j) - 1];
		hexStr[(i - j) - 1] = temp;
	}

	hexStr[i] = '\0';

	return hexStr;
}

char* URLEncoding(char* data, unsigned int count) {
	char* result = malloc(1);
	result[0] = '\0';

	for (int i = 0; i < count; ++i)
	{
		char c = data[i];

		if (('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || ('0' <= c && c <= '9'))
		{
			strncat(result, &c, 1);
		}
		else
		{
			strncat(result, "%", 1);

			char s[3] = { '0', '0', '\0' };
			char* hexStr = DecimalToHexadecimal(c);

			if (strlen(hexStr) < 2) {
				s[1] = hexStr[0];
			}
			else {
				s[0] = hexStr[0];
				s[1] = hexStr[1];
			}

			strcat(result, s);
		}
	}

	return result;
}
								

Example

									char* data = "jdfgsdhfsdfsd 6445dsfsd7fg/*/+bfjsdgf%$^";
char* value = URLEncoding(data, strlen(data));
								

Output

									jdfgsdhfsdfsd%206445dsfsd7fg%2F%2A%2F%2Bbfjsdgf%25%24%5E