/*-
 * Copyright (c) 1997 Joe Greco, sol.net Network Services
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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	<stdio.h>
#include	<errno.h>
#include	<fcntl.h>





#define		NEWSSPOOL	"/news/spool/news"
#define		NAMELEN		256
#define		FILENAMELEN	1024





int diab_read(char *namepos, char *buf, int szbuf)
{
	char filename[FILENAMELEN];
	char name[NAMELEN], *ptr, *nptr;
	static char lastname[NAMELEN] = { 0 };
	static int fd = -1;
	off_t offset;
	size_t size;
	int rval;

	for (ptr = namepos, nptr = name; *ptr && *ptr != ':' && *ptr != ' '; ) {
		*nptr++ = *ptr++;
	}
	*nptr = '\0';

	if (*ptr != ':' && *ptr != ' ') {
#ifdef	DEBUG
		fprintf(stderr, "error: parsing article location, no colon\n");
#endif
		return(-1);
	}
	ptr++;

	/* XXX this is not right, of course */
	if (sscanf(ptr, "%d,%d", (int *)&offset, (int *)&size) != 2) {
#ifdef	DEBUG
		fprintf(stderr, "error: parsing article location, sscanf\n");
#endif
		return(-1);
	}
	if (strcmp(lastname, name)) {
		if (fd >= 0) {
			close(fd);
			fd = -1;
		}
	}
	if (fd < 0) {
		snprintf(filename, sizeof(filename), "%s/%s", NEWSSPOOL, name);
		if ((fd = open(filename, O_RDONLY, 0)) < 0) {
#ifdef	DEBUG
		fprintf(stderr, "error: opening article file, open fails, %d\n", errno);
#endif
			return(-1);
		}
		snprintf(lastname, sizeof(lastname), "%s", name);
	}
	if (lseek(fd, offset, SEEK_SET) < 0) {
#ifdef	DEBUG
		fprintf(stderr, "error: seeking to article location, %d\n", errno);
#endif
		return(-1);
	}
	if (size + 1 > szbuf) {
		/* Too big for buffer - read what we can */
		if ((rval = read(fd, buf, szbuf)) != szbuf) {
#ifdef	DEBUG
		fprintf(stderr, "error: reading article data (toobig), read fails, %d\n", errno);
#endif
			return(-1);
		}
		for (ptr = buf, nptr = buf + rval; ptr < nptr; ) {
			if (! *ptr++) {
#ifdef	DEBUG
				fprintf(stderr, "error: checking article data (toobig), data byte null\n");
#endif
				return(-1);
			}
		}
		/* Can't check last byte that didn't fit */
		return(rval);
	} else {
		/* Fits in buffer - go for it */
		if ((rval = read(fd, buf, size + 1)) != size + 1) {
#ifdef	DEBUG
		fprintf(stderr, "error: reading article data (itfits), read fails, %d\n", errno);
#endif
			return(-1);
		}
		for (ptr = buf, nptr = buf + rval - 1; ptr < nptr; ) {
			if (! *ptr++) {
#ifdef	DEBUG
				fprintf(stderr, "error: checking article data (itfits), data byte null\n");
#endif
				return(-1);
			}
		}
		if (*ptr) {
#ifdef	DEBUG
		fprintf(stderr, "error: checking article data (itfits), last byte not null\n");
#endif
			return(-1);
		}
		return(rval - 1);
	}
}




#if 0
int main()
{
	char buffer[8192];
	char n[8192];
	int start = time(NULL);
	int i;

	while (! feof(stdin)) {
		gets(buffer);
		if (! feof(stdin)) {
			printf("%s %d\n", buffer, diab_read(buffer, n, sizeof(n)));
			i++;
			fflush(stdout);
		}
	}
	printf("\n%d arts in %d secs\n", i, time(NULL) - start);
}
#endif


#ifdef MAINLINE
int main(int argc, char *argv[])
{
	char abuf[1100000];
	int rval;

	if (argc != 2) {
		fprintf(stderr, "diab-read: usage: diab-read <article>\n");
		exit(1);
	}
	if ((rval = diab_read(argv[1], abuf, sizeof(abuf))) < 0) {
		perror("diab_read");
		exit(1);
	}
	write(fileno(stdout), abuf, rval);
	exit(0);
}
#endif