bitwise unwise

bit.c

void print_as_binary(unsigned int num)
{
	unsigned int mask = (1 << 31);
	int i;

	for (i = 1; i <= 32; i++) {
		printf("%d", (num & mask) ? 1 : 0);
		mask >>= 1;

		if (i % 4 == 0)
			putchar(' ');
	}
}

int FindFirstSet(unsigned BitMap, unsigned start)
{
	unsigned Mask = (1 << start);

	while (Mask) {
		if (BitMap & Mask) return start;
		++start;
		Mask <<= 1;
	}
	return -1;
}

int FindFirstClr(unsigned BitMap, unsigned start)
{
	return FindFirstSet(~BitMap, start);
}

int SetBit(unsigned BitMap, unsigned position)
{
	return BitMap | (1 << position);
}

int ClrBit(unsigned BitMap, unsigned position)
{
	return BitMap & ~(1 << position);
}

int tolower(int c)
{
	return c | 0x20;
}

int toupper(int c)
{
	return c & ~0x20;
}

int switchCase(int c)
{
	return (c & 0x20) ? toupper(c) : tolower(c);
}

int CharToInt(char *num)
{
	int i = 0;
	int sum = 0;

	while (num[i] != '\0') {
		sum = (sum * 10) + (num[i] & 0x0F);
		i++;
	}
	
	return sum;
}

int ToDate(int month, int day, int year)
{
	return month << 12 | day << 7 | year;
}

int ExtractMonth(int pdate)
{
	return pdate >> 12;
}

int ExtractDay(int pdate)
{
	return pdate >> 7 & 0x1F;
}

int ExtractYear(int pdate)
{
	return pdate & 0x7F;
}

int CntBits(int num)
{
	int count = 0;

	do {
		if (num & 1) count++;
		num >>= 1;
	} while (num);

	return count;
}