/* tr - like unix tr

** THIS PROGRAM MUST BE COMPILED WITH THE EXTENDED PREPROCESSOR
** IE: cc TR -p

 by jim mckim

 this program may be used in several ways.  By example:

 	tr A-Z a-z <input >output
	will convert upper case to lower case

	tr -c !-~ ? <input >output
	will convert unprintable characters to question marks

	tr -cs !-~ \40 <input >output
	will convert unprintable characters to spaces and squeeze out extra spaces

	tr -d \177-\377 <input
	will remove all characters whose eighth bit is set

 comments about this can reach me via BIX (jmckim)
 or telephone (216 835 3845)
 or USPS
 (Jim McKim
 30224 Wolf Rd.
 Bay Village, OH 44140)

 (i gladly accept bug reports; bug fixes will make me ecstatic)

Compile command: cc tr -fop
*/

#include <stdio.h>
#include <file.h>

#define TTSIZE 257
#define isodigit(c) ((c)>='0' && (c)<='7')

TellHow()
{
fputs("usage: tr [-flags] string1 string2 <input >output\n", stderr);
fputs("where flags are:\n",stderr);
fputs("c  compliment string1 (e.g. all NOT in string1)\n",stderr);
fputs("d  delete if in string1\n",stderr);
fputs("s  squeeze out duplicates if in string2\n",stderr);
fputs("r  raw (no cr/lf conversion) (MSDOS only)\n",stderr);
exit(-1);
}

Interpret(input,output)
char *input, *output;
{
	int startc, endc;
	int i;
	int range_flag;  /* true when '-' has been seen */
	int got_next;  /* true when char after '-' has been seen */

	*output = range_flag = got_next = 0;
	while (*input)
	{
		if (*input == '\\')
		{
			++input;
			if (isodigit(*input))
			{
				/* got an octal constant */
				i = *input - '0';
				if (isodigit(*(input+1)))
				{
					i = i*8 + *++input - '0';
					if (isodigit(*(input+1)))
						i = i*8 + *++input - '0';
				}
				*output++ = i;
				if (range_flag)
					got_next = 1;
			}
			else
			{
				/* got a \c type character */
				*output++ = *input;
				if (range_flag)
					got_next = 1;
			}
		}
		else if (*input == '-')
		{
			/* got a range */
			range_flag = 1;
		}
		else
		{
			/* got a normal character */
			*output++ = *input;
			if (range_flag)
				got_next = 1;
		}

		++input;

		if (range_flag && got_next)
		{
			startc = *(output-2);
			endc = *(output-1);
			output -= 2;
			for (i=startc; i<=endc; ++i)
				*output++ = i;
			range_flag = got_next = 0;
		}
	} /* end while */
	*output = '\0';
}

main(argc,argv)
int argc;
char *argv[];
{
	char incode[TTSIZE], outcode[TTSIZE], trtbl[TTSIZE];
	char inset[TTSIZE];
	char inch, outch, old_outch;
	int i, j, iarg;
	char c_flag, d_flag, s_flag;
	char *iap;

	iarg = 1;
	c_flag = d_flag = s_flag = 0;

	/* get the switches */
	while ((iarg <= argc) && (*argv[iarg] == '-'))
	{
		iap = argv[iarg++] + 1;  /* point past '-' */
		while (*iap)
			switch (*iap++)
			{
			case 'c':	/* Compliment string */
				c_flag = 1;
				break;
			case 'd':	/* Delete */
				d_flag = 1;
				break;
			case 's':	/* Squeeze out duplicates */
				s_flag = 1;
				break;
			case 'r':	/* Raw I/O mode */
				*stdin |= F_BINARY;
				*stdout |= F_BINARY;
				break;
			default:
				TellHow();
			}
	}

	if (iarg+1 >= argc)
	{
		TellHow();
	}

	for (i=0; i<TTSIZE; ++i)
	{
		trtbl[i] = i;
		inset[i] = '\0';
		incode[i] = '\0';
		outcode[i] = '\0';
	}

	Interpret(argv[iarg++],incode);
	Interpret(argv[iarg],outcode);

	i = 0;
	j = 0;
	while (incode[i])
	{
		inset[incode[i]] = 1;
		if (c_flag == 0)
		{
			trtbl[incode[i]] = outcode[j];
			/* if next is null, dup last */
			if (outcode[j+1])
				++j;
		}
		++i;
	}

	if (c_flag == 1)
	{
		j = 0;
		for (i=0; i<TTSIZE; ++i)
		{
			if (inset[i] == 0)
			{
				inset[i] = 1;
				trtbl[i] = outcode[j];
				if (outcode[j+1])
					++j;
			}
			else
			{
				inset[i] = 0;
				trtbl[i] = i;
			}
		}
	}

/* To speed up processsing, switch stdio streams to buffered */
	stdin = setbuf(stdin, 1024);
	stdout = setbuf(stdout, 1024);

	outch = '\0';
	while ((inch=getc(stdin)) != EOF)
	{
		old_outch = outch;
		outch = trtbl[inch];
		if (d_flag)
			if (inset[inch])
				continue;
		if (s_flag)
			if (inset[inch])
				if (old_outch == outch)
					continue;
		putc(outch, stdout);
	}

	fflush(stdout);		/* Insure output buffer is written */
}