/*	$NetBSD: word.c,v 1.10 2021/05/02 12:50:43 rillig Exp $	*/

/*-
 * Copyright (c) 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Barry Brachman.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)word.c	8.1 (Berkeley) 6/11/93";
#else
__RCSID("$NetBSD: word.c,v 1.10 2021/05/02 12:50:43 rillig Exp $");
#endif
#endif /* not lint */

#include <sys/types.h>
#include <sys/stat.h>

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "bog.h"
#include "extern.h"

static char *dictspace, *dictend;
static char *sp;

static int first = 1, lastch = 0;

extern struct dictindex dictindex[];
extern int wordlen;

/*
 * Return the next word in the compressed dictionary in 'buffer' or
 * NULL on end-of-file
 */
char *
nextword(FILE *fp)
{
	int ch, pcount;
	char *p;
	static char buf[MAXWORDLEN + 1];

	if (fp == NULL) {
		if (sp == dictend)
			return (NULL);

		p = buf + (int) *sp++;

		/*
		 * The dictionary ends with a null byte
		 */
		while (*sp >= 'a')
			if ((*p++ = *sp++) == 'q')
				*p++ = 'u';
	} else {
		if (first) {
			if ((pcount = getc(fp)) == EOF)
				return (NULL);
			first = 0;
		} else if ((pcount = lastch) == EOF)
			return (NULL);

		p = buf + pcount;

		while ((ch = getc(fp)) != EOF && ch >= 'a')
			if ((*p++ = ch) == 'q')
				*p++ = 'u';
		lastch = ch;
	}
	wordlen = (int) (p - buf);
	*p = '\0';
	return (buf);
}

/*
 * Reset the state of nextword() and do the fseek()
 */
long
dictseek(FILE *fp, long offset, int ptrname)
{
	if (fp == NULL) {
		if ((sp = dictspace + offset) >= dictend)
			return (-1);
		return (0);
	}

	first = 1;
	return (fseek(fp, offset, ptrname));
}

FILE *
opendict(const char *dict)
{
	FILE *fp;

	if ((fp = fopen(dict, "r")) == NULL)
		return (NULL);
	return (fp);
}

/*
 * Load the given dictionary and initialize the pointers
 */
int
loaddict(FILE *fp)
{
	struct stat statb;
	long n;
	int st;
	char *p;

	if (fstat(fileno(fp), &statb) < 0) {
		(void)fclose(fp);
		return (-1);
	}

	/*
	 * An extra character (a sentinel) is allocated and set to null
	 * to improve the expansion loop in nextword().
	 */
	if ((dictspace = malloc(statb.st_size + 1)) == NULL) {
		(void)fclose(fp);
		return (-1);
	}
	n = (long)statb.st_size;
	sp = dictspace;
	dictend = dictspace + n;

	p = dictspace;
	st = -1;
	while (n > 0 && (st = fread(p, 1, BUFSIZ, fp)) > 0) {
		p += st;
		n -= st;
	}
	if (st < 0) {
		(void)fclose(fp);
		warnx("Error reading dictionary");
		return (-1);
	}
	*p = '\0';
	return (0);
}

/*
 * Dependent on the exact format of the index file:
 * Starting offset field begins in column 1 and length field in column 9
 * Taking the easy way out, the input buffer is made "large" and a check
 * is made for lines that are too long
 */
int
loadindex(const char *indexfile)
{
	int i, j;
	char buf[BUFSIZ];
	FILE *fp;

	if ((fp = fopen(indexfile, "r")) == NULL) {
		warn("Can't open '%s'", indexfile);
		return (-1);
	}
	i = 0;
	while (fgets(buf, sizeof(buf), fp) != NULL) {
		if (strchr(buf, '\n') == NULL) {
			warnx("A line in the index file is too long");
			(void) fclose(fp);
			return(-1);
		}
		j = *buf - 'a';
		if (i != j) {
		    warnx("Bad index order");
		    (void) fclose(fp);
		    return(-1);
		}
		dictindex[j].start = atol(buf + 1);
		dictindex[j].length = atol(buf + 9) - dictindex[j].start;
		i++;
	}
	(void) fclose(fp);
	if (i != 26) {
		warnx("Bad index length");
		return(-1);
	}
	return(0);
}
