/*
 * $Id: //websites/unixwiz/newroot/tools/achart.c#2 $
 *
 * written by:	Stephen J. Friedl
 *		Tustin, CA  92780
 *		steve@unixwiz.net
 *	
 *	This is a self-contained ASCII chart program.  It takes a base as
 *	an argument and prints a chart with the lower 128 ASCII chars.
 *	The default base is decimal, but an alternate base of ( 8, 10 or
 *	16 ) can be specified as well.  If the indicated base is prefixed
 *	with a minus sign, the lower control characters are displayed with
 *	their mnemonics (NUL, EOT, etc.) instead of their control-character
 *	representation. 
 */
#include	<stdio.h>
#include	<stdlib.h>

/*------------------------------------------------------------------------
 * this little table contains the representations of all the characters
 * in the lower part of the set.  For the time being, we don't care about
 * the chars >= 128.
 */
static const char	*prtchar[] = {
	"^@",   "^A",   "^B",   "^C",   "^D",   "^E",   "^F",   "^G",
	"^H",   "^I",   "^J",   "^K",   "^L",   "^M",   "^N",   "^O",
	"^P",   "^Q",   "^R",   "^S",   "^T",   "^U",   "^V",   "^W",
	"^X",   "^Y",   "^Z",   "^[",   "^\\",  "^]",   "^^",   "^_",
	"SP",   "!",    "\"",   "#",    "$",    "%",    "&",    "'",
	"(",    ")",    "*",    "+",    ",",    "-",    ".",    "/",
	"0",    "1",    "2",    "3",    "4",    "5",    "6",    "7",
	"8",    "9",    ":",    ";",    "<",    "=",    ">",    "?",
	"@",    "A",    "B",    "C",    "D",    "E",    "F",    "G", 
	"H",    "I",    "J",    "K",    "L",    "M",    "N",    "O", 
	"P",    "Q",    "R",    "S",    "T",    "U",    "V",    "W", 
	"X",    "Y",    "Z",    "[",    "\\",   "]",    "^",    "_", 
	"`",    "a",    "b",    "c",    "d",    "e",    "f",    "g", 
	"h",    "i",    "j",    "k",    "l",    "m",    "n",    "o", 
	"p",    "q",    "r",    "s",    "t",    "u",    "v",    "w", 
	"x",    "y",    "z",    "{",    "|",    "}",    "~",    "^?"
};

static void	add_mnemonics(void);

int main(int argc, char **argv)
{
char	*base_name;		/* printable name of the base		*/
int	i,
	ccol    = 0,		/* current column counter		*/
	maxcols = 8,		/* total number of columns allowed	*/
	base    = 10;		/* current base of interest		*/

	/*----------------------------------------------------------------
	 * if we have a base specified, pick it apart.  Note that we don't
	 * check for excess args here...
	 */
	if (argc > 1)
		base = atoi(argv[1]);

	/*----------------------------------------------------------------
	 * if the base is less than zero, use the alternate display format.
	 */
	if (base < 0)
		add_mnemonics(), base = -base;

	/*----------------------------------------------------------------
	 * validate the base and make sure we have something valid.  We
	 * also determine the base string.
	 */
	switch (base)
	{
	  case 10:
		base_name = "decimal";
		break;

	  case 16:
		base_name = "hex";
		break;

	  case  8:
		base_name = "octal";
		break;

	  default:
		fprintf(stderr, "%s: base must be 10, 16, or 8\n", argv[0]);

		return EXIT_FAILURE;
	}

	/*----------------------------------------------------------------
	 * print a header to remind the user what we are doing
	 */
	printf("\nASCII chart, %s representation\n\n", base_name);

	/*----------------------------------------------------------------
	 * now run through the chart.  We do this in 16 rows of 8 chars each.
	 */
	for (i = 0; i < 128; i++)
	{
		/*--------------------------------------------------------
		 * if this is not the first column, we need the separator
	 	 * between it and the previosu column.
		 */
		if (ccol++ > 0)
			printf(" | ");

		/*--------------------------------------------------------
		 * now actualy do the output of the character's index
		 */
		switch (base)
		{
		  case 10:	printf("%3d", i); break;
		  case  8:	printf("%03o", i); break;
		  case 16:	printf("%02X", i); break;
		}

		/*--------------------------------------------------------
		 * now put the name of the character
		 */
		printf(" %3s", prtchar[i]);

		/*--------------------------------------------------------
		 * If we are at the end of a line, kick out a newline.
		 */
		if (ccol >= maxcols)
			putchar('\n'), ccol = 0;
	}

	putchar('\n');

	return EXIT_SUCCESS;
}

/*
 * add_mnemonics()
 *
 *	Run through the prtchar[] table and stuff in the ASCII control
 *	code abbreviations.
 */
static void add_mnemonics(void)
{
	prtchar[  0] = "NUL";
	prtchar[  1] = "SOH";
	prtchar[  2] = "STX";
	prtchar[  3] = "ETX";
	prtchar[  4] = "EOT";
	prtchar[  5] = "ENQ";
	prtchar[  6] = "ACK";
	prtchar[  7] = "BEL";
	prtchar[  8] = "BS";
	prtchar[  9] = "HT";
	prtchar[ 10] = "LF";
	prtchar[ 11] = "VT";
	prtchar[ 12] = "FF";
	prtchar[ 13] = "CR";
	prtchar[ 14] = "SO";
	prtchar[ 15] = "SI";
	prtchar[ 16] = "DLE";
	prtchar[ 17] = "DC1";
	prtchar[ 18] = "DC2";
	prtchar[ 19] = "DC3";
	prtchar[ 20] = "DC4";
	prtchar[ 21] = "NAK";
	prtchar[ 22] = "SYN";
	prtchar[ 23] = "ETB";
	prtchar[ 24] = "CAN";
	prtchar[ 25] = "EM";
	prtchar[ 26] = "SUB";
	prtchar[ 27] = "ESC";
	prtchar[ 28] = "FS";
	prtchar[ 29] = "GS";
	prtchar[ 30] = "RS";
	prtchar[ 31] = "US";
	prtchar[127] = "DEL";
}