NSBaseConversion.mm

/**
   Original Code From, Md. Mahmud Ahsan, http://thinkdiff.net/mixed/base-conversion-handle-upto-36-bases/, 2008.02.28
   Adapted Objective-C, Furkan Mustafa, 2013.05.28
   Description: Alpha Numeric Base Conversion, Handles upto base 36
*/

NSString* reverseString(NSString* original) {
	const char* chars = [original cStringUsingEncoding:NSASCIIStringEncoding];
	int length = strlen(chars);
	char* new = (char*)malloc(length+1);
	for (int i = 0; i < length; i++)
		new[i] = chars[length - i - 1];
	new[length] = '\0';
	NSString* reverseString = [NSString stringWithCString:new encoding:NSASCIIStringEncoding];
	free(new);
	return reverseString;
}

int otherToDec(NSString *original, int base) {
	const char* str = [original.uppercaseString cStringUsingEncoding:NSASCIIStringEncoding];
	int len = strlen(str);
	int power = len - 1;
	long long i, number, j;

	number = 0;
	for (i = 0; i < len; ++i) {
		if (str[i] >= 'A' && str[i] <= 'Z')
			j = str[i] - 65 + 10;
		else
			j = str[i] - 48;
		number += j * pow(base, power);
		power--;
	}
	return number;
}

NSString* decToOther(int number, int base) {
	NSMutableString* final = NSMutableString.string;
	int temp, j;

	j = -1;
	do {
		temp = number % base;
		if (temp < 10)
			[final appendFormat:@"%c", 48 + temp];
		else
			[final appendFormat:@"%c", 65 + temp - 10];
		number = number / base;
	} while (number != 0);

	return reverseString(final);
}