#include <stdio.h>

#define	reg	register
#define	uns	unsigned
#define	byte	unsigned char


/* I/O, arguments */

char	*ifile = NULL;
FILE	*ichan;
char	*ofile = NULL;
FILE	*ochan;

#define	IBUFSIZ 16777216		/* Input buffer */
char	ibuf[IBUFSIZ];			/* Input buffer (one line) */
char	tbuf[128];			/* Token buffer */


/* Command line, file parse status */

uns	cargc;
char	**cargv;

byte	showprog = 0;			/* Show progress */
long	cline = 0;			/* Current line */
long	cmask = 32767;			/* Print a "*" every this many lines */
uns	nstars = 0;


/* Parse arguments; call main routine to actually parse the file.
 */

main(argc, argv)
	uns	argc;
	char	*argv[];

{	if (argc == 1) {
		printf("wkf -i {infile} -o {outfile} -fp -pp <nlines>\n");
		exit(1);
		}


	ichan = stdin;
	ochan = stdout;


	cargv = argv;
	cargc = argc;

	for (cargc--, cargv++; (cargc > 0); cargc--, cargv++) {
		if (**cargv == '-') {
			arg_doflag();
			continue;
			}

		break;
		}

	copydata();

	done(0);
}


/* Deal with all flag arguments; set debugger and feature flags,
 * etc.
 */

arg_doflag()

{	reg	char	*arg;

	arg = *cargv;
	arg++;

	switch(*arg++) {

	  case 'f':	while (*arg != '\0')
				arg_dofeat(arg++);
			break;

	  case 'n':
	  case 'p':	arg_doparam(arg);
			break;


	  case 'i':	cargc--;
			cargv++;

			if (ifile != NULL) {
				printf("Duplicate input file %s\n", *cargv);
				done(1);
				}

			ifile = *cargv;
			if ((ichan = fopen(*cargv, "r")) == NULL) {
				printf("Can't open file %s\n", *cargv);
				done(1);
				}

			break;

	  case 'o':	cargc--;
			cargv++;

			if (ofile != NULL) {
				printf("Duplicate input file %s\n", *cargv);
				done(1);
				}

			ofile = *cargv;
			if ((ochan = fopen(*cargv, "w")) == NULL) {
				printf("Can't open file %s\n", *cargv);
				done(1);
				}

			break;

	  default:	printf("Bad option %c\n", *--arg);
			done(1);
	  }
}

/* Handle parameters.
 */

arg_doparam(arg)
	char	*arg;

{	switch (*arg) {

	  case 'p':	cargc--;
			cargv++;
			cmask = ((1 << atoi(*cargv)) - 1);
			break;

	  default:	printf("Bad parameter option %c\n", *arg);
			done(1);
	  }
}


/* Set feature flags.
 */

arg_dofeat(arg)
	char	*arg;

{	switch (*arg) {

	  case 'p':	showprog++;
			break;

	  default:	printf("Bad feature option %c\n", *arg);
			done(1);
	  }
}


/* Process input file.
 *
 * Only nested multi-line items are:
 *  <namespaces>, <page>, <revision>, <siteinfo>:
 * those are handled specially.
 *
 * Yes, I know this is really ugly/kludgy, but it's *really* fast.
 */

copydata()

{	reg	char	*cp;


	while (1) {

		if (fgets(&ibuf[0], IBUFSIZ, ichan) == NULL) {
			return;
			}
		if (feof(ichan)) {
			return;
			}


		cline++;
		if (showprog && ((cline & cmask) == 0)) {
			printf("*");
			fflush(stdout);
			if (nstars++ == 72) {
				printf("\n");
				fflush(stdout);
				nstars = 0;
				}
			}
			

		for (cp = &ibuf[0]; ((*cp == ' ') || (*cp == '\t')); cp++);

		if (*cp++ != '<') {
			printf("unexpected char '%c' in '%s'", *--cp, &ibuf[0]);
			done(1);
			}

		if (*cp == '/') {
			cp++;

			if ((*cp == 'n') && (strncmp(cp, "namespaces>", 11) == 0)) {
				fputs(&ibuf[0], ochan);
				continue;
				}
			if ((*cp == 'p') && (strncmp(cp, "page>", 5) == 0)) {
				fputs(&ibuf[0], ochan);
				continue;
				}
			if ((*cp == 'r') && (strncmp(cp, "revision>", 9) == 0)) {
				fputs(&ibuf[0], ochan);
				continue;
				}
			if ((*cp == 's') && (strncmp(cp, "siteinfo>", 9) == 0)) {
				fputs(&ibuf[0], ochan);
				continue;
				}

			printf("unexpected endtoken '%s' in '%s'", cp, &ibuf[0]);
			done(1);
			}

		if (*cp != 't') {
			putitem(cp);
			continue;
			}
		
		if (strncmp(cp, "text ", 5) != 0) {
			putitem(cp);
			continue;
			}
	
		cp += 5;
		discitem(cp, "text>", 5);
		}
}


/* Copy complete entry, up to matching terminating token; possibly multiple
 * lines. Handles three cases:
 *
 * - </{foo}> at the end of the current line
 * </{foo}> at the start of a following line
 * </{foo}> at the end of a following line
 *
 * Has to make copy of token because calls to read will bash the copy
 * passed as an arg. (Makes the copy even in cases it's not needed
 * because the length is needed in all cases.)
 *
 * Yes, I know this (and the code) is really ugly/kludgy, but it's fast.
 */

putitem(tnp)
	char	*tnp;

{	reg	char	*cp, *tp;
		uns	tlen;
		char	t;
	

	fputs(&ibuf[0], ochan);

	cp = tnp;
	tp = &tbuf[0];
	tlen = 0;
	
	for (;;) {
		t = *cp++;
		*tp++ = t;
		tlen++;
		if (t == ' ')
			return;
		if (t == '>')
			break;
		}


	while ((*cp != '\n') && (*cp != 0))
		cp++;

	if (*cp == 0) {
		printf("put unexpected EOF '%s' '%s'", tnp, &ibuf[0]);
		done(1);
		}

	cp -= tlen;
	if (strncmp(cp, tnp, tlen) == 0)
		return;


	while (1) {
		if (fgets(&ibuf[0], IBUFSIZ, ichan) == NULL)
			return;
		if (feof(ichan))
			return;

		fputs(&ibuf[0], ochan);

		cline++;
		if (showprog && ((cline & cmask) == 0)) {
			printf("*");
			fflush(stdout);
			if (nstars++ == 72) {
				printf("\n");
	       			fflush(stdout);
				nstars = 0;
				}
			}


		cp = &ibuf[0];
		if ((*cp++ == '<') && (*cp++ == '/')) {
			if (strncmp(cp, &tbuf[0], tlen) != 0) {
				printf("put <%s unexpected entity '%s' in '%s'",
					&tbuf[0], cp,  &ibuf[0]);
				done(1);
				}
			return;
			}


		for (cp = &ibuf[0]; ((*cp != '\n') && (*cp != 0)); cp++);

		if (*cp == 0) {
			printf("<%s unexpected EOF '%s'", &tbuf[0], &ibuf[0]);
			done(1);
			}

		cp -= tlen;
		if (strncmp(cp, &tbuf[0], tlen) == 0)
			return;
		}
}


/* Discard complete entry, up to matching terminating token; possibly multiple
 * lines. Handles four cases:
 *
 * <foo {mumblage} /> at the end of the current line
 * - </{foo}> at the end of the current line
 * </{foo}> at the start of a following line
 * </{foo}> at the end of a following line
 *
 * Yes, I know this (and the code) is really ugly/kludgy, but it's fast.
 */

discitem(tnp, tok, tlen)
	char	*tnp;
	char	*tok;
	uns	tlen;

{	reg	char	*cp;
	

	for (cp = tnp; ((*cp != '\n') && (*cp != 0)); cp++);

	if (*cp == 0) {
		printf("disc <%s unexpected EOF '%s' '%s'", tok, tnp, &ibuf[0]);
		done(1);
		}


	if ((*--cp == '>') && (*--cp == '/'))
		return;

	cp -= (tlen - 2);
	if (strncmp(cp, tok, tlen) == 0)
		return;


	while (1) {
		if (fgets(&ibuf[0], IBUFSIZ, ichan) == NULL)
			return;
		if (feof(ichan))
			return;

		cline++;
		if (showprog && ((cline & cmask) == 0)) {
			printf("*");
			fflush(stdout);
			if (nstars++ == 72) {
				printf("\n");
				fflush(stdout);
				nstars = 0;
				}
			}


		cp = &ibuf[0];
		if ((*cp++ == '<') && (*cp++ == '/')) {
			if (strncmp(cp, tok, tlen) != 0) {
				printf("disc <%s unexpected entity '%s' in '%s'",
					tok, cp,  &ibuf[0]);
				done(1);
				}

			return;
			}


		for (cp = &ibuf[0]; ((*cp != '\n') && (*cp != 0)); cp++);

		if (*cp == 0) {
			printf("<%s unexpected EOF '%s'", tok, &ibuf[0]);
			done(1);
			}

		cp -= tlen;
		if (strncmp(cp, tok, tlen) == 0)
			return;
		}
}


/* Flush buffers, done.
 */

done(code)
	int	code;

{
	fflush(ochan);

	if (showprog) {
		printf("\nlines: %d\n", cline);
		fflush(stdout);
		}

	exit(code);
}