#include <stdio.h>  /* putc() */
#include <limits.h> /* CHAR_BIT, INT_MAX, LONG_MIN */

#define PutC(c) (putc( (char) (c), stdout ))
#define PutD(d) (PutC( (char) ((d)<10)?('0'+(d)):('A'+(d)-10) ))

/* LABELS FOR BITS IN THE 'HOW' MASK */
#define IR_BIT_BASE (0x01)
#define IR_BIT_PACK (0x02)
#define IR_BIT_ORDER (0x04)
/* SYMBOLIC CONSTANTS FOR EACH 'HOW' MODE */
#define IR_BIN (0x00)
#define IR_HEX (IR_BIT_BASE)
#define IR_PACKED (0x00)
#define IR_SPACED (IR_BIT_PACK)
#define IR_FWD (0x00)
#define IR_REV (IR_BIT_ORDER)
/* TO USE: ADD or BITWISE-OR TOGETHER. EG: */
/* FOR REVERSED, SPACED, BIN: how = IR_REV + IR_SPACED + IR_BIN */
/* ALTERNATE WAY:             how = IR_REV | IR_SPACED | IR_BIN */

/* The format chosen for this demo */
#define FORMAT ( IR_FWD | IR_SPACED | IR_BIN )

int PutIR(void *base, size_t size, int how)
{
	unsigned char *ptr, *start;
	unsigned char mask;
	int i, nibble, step, chars;

	/* Set up based on byte order */
	start = (unsigned char *) base + ((how & IR_BIT_ORDER)? (size-1) : 0);
	step = (how & IR_BIT_ORDER)? -1: 1;

	/* Process bytes one at a time */
	for (i = 0, chars = 0, ptr = start; i < size; ptr += step, i++)
	{
		/* Inter-byte space if requested */
		if ( (how & IR_BIT_PACK) && (ptr != start) )
		{
			PutC(' ');
			chars++;
		}

		/* Print out the byte */
		if (how & IR_BIT_BASE)
			for (nibble = (CHAR_BIT - 1)/4; nibble >= 0; nibble--)
			{
				PutD( ( (0x0F << 4*nibble) & (*ptr)) >> 4*nibble );
				chars++;
			}
		else
			for (mask = 1 << (CHAR_BIT - 1); mask; mask >>= 1)
			{
				PutD( (mask & *ptr)?  1  :  0  );
				chars++;
			}
	}
	return chars;
}

int main(void)
{
	int junk;
	long junk_l;

	junk = INT_MAX;
	PutIR(&junk, sizeof(junk), FORMAT);

	PutC('\n');

	junk_l = LONG_MIN;
	PutIR(&junk_l, sizeof(junk_l), FORMAT);

	return 0;
}