475 lines
10 KiB
C
475 lines
10 KiB
C
/*
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* Empire - A multi-player, client/server Internet based war game.
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* Copyright (C) 1986-2005, Dave Pare, Jeff Bailey, Thomas Ruschak,
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* Ken Stevens, Steve McClure
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* ---
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*
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* See the "LEGAL", "LICENSE", "CREDITS" and "README" files for all the
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* related information and legal notices. It is expected that any future
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* projects/authors will amend these files as needed.
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*
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* ---
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*
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* file.c: Misc. operations on files
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*
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* Known contributors to this file:
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* Dave Pare, 1989
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* Steve McClure, 2000
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*/
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#include <errno.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <string.h>
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#if !defined(_WIN32)
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#include <unistd.h>
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#endif
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#include "misc.h"
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#include "nsc.h"
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#include "file.h"
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#include "common.h"
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#include "gen.h"
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static int fillcache(struct empfile *, int);
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static int do_write(struct empfile *, void *, int, int);
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/*
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* Open the binary file for table TYPE (EF_SECTOR, ...).
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* HOW are EFF_OPEN flags to control operation.
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* Return non-zero on success, zero on failure.
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* You must call ef_close() before the next ef_open().
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*/
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int
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ef_open(int type, int how)
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{
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struct empfile *ep;
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int oflags, fd, fsiz, size;
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if (ef_check(type) < 0)
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return 0;
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if (CANT_HAPPEN(how & ~EFF_OPEN))
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how &= EFF_OPEN;
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ep = &empfile[type];
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if (CANT_HAPPEN(ep->fd >= 0))
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return 0;
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oflags = O_RDWR;
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if (how & EFF_RDONLY)
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oflags = O_RDONLY;
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if (how & EFF_CREATE)
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oflags |= O_CREAT | O_TRUNC;
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#if defined(_WIN32)
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oflags |= O_BINARY;
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#endif
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if ((fd = open(ep->file, oflags, 0660)) < 0) {
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logerror("Can't open %s (%s)", ep->file, strerror(errno));
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return 0;
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}
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fsiz = fsize(fd);
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if (fsiz % ep->size) {
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logerror("Can't open %s (file size not a multiple of record size %d)",
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ep->file, ep->size);
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close(fd);
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return 0;
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}
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ep->fids = fsiz / ep->size;
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if (how & EFF_MEM)
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ep->csize = ep->fids;
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else
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ep->csize = max(1, blksize(fd) / ep->size);
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size = ep->csize * ep->size;
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if (size) {
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ep->cache = malloc(size);
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if (ep->cache == NULL) {
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logerror("Can't open %s: out of memory", ep->file);
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close(fd);
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return 0;
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}
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} else {
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ep->cache = NULL;
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}
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ep->baseid = 0;
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ep->cids = 0;
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ep->flags = (ep->flags & ~EFF_OPEN) | (how & ~EFF_CREATE);
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ep->fd = fd;
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if ((how & EFF_MEM) && ep->fids) {
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if (fillcache(ep, 0) != ep->fids) {
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ep->cids = 0; /* prevent cache flush */
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ep->flags &= ~EFF_OPEN; /* maintain invariant */
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ef_close(type);
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return 0;
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}
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}
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return 1;
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}
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/*
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* Close the file containing objects of the type 'type', flushing the cache
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* if applicable.
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*/
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int
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ef_close(int type)
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{
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struct empfile *ep;
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int retval;
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retval = ef_flush(type);
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ep = &empfile[type];
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ep->flags &= ~EFF_OPEN;
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free(ep->cache);
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ep->cache = NULL;
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if (close(ep->fd) < 0) {
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logerror("Error closing %s (%s)", ep->name, strerror(errno));
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retval = 0;
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}
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ep->fd = -1;
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return retval;
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}
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/*
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* Flush the cache of the file containing objects of type 'type' to disk.
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*/
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int
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ef_flush(int type)
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{
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struct empfile *ep;
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if (ef_check(type) < 0)
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return 0;
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ep = &empfile[type];
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if (CANT_HAPPEN(ep->fd < 0))
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return 0;
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/*
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* We don't know which cache entries are dirty. ef_write() writes
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* through, but direct updates through ef_ptr() don't. They are
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* allowed only with EFF_MEM. Assume the whole cash is dirty
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* then.
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*/
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if (!(ep->flags & EFF_RDONLY) && (ep->flags & EFF_MEM))
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return do_write(ep, ep->cache, ep->baseid, ep->cids) >= 0;
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return 1;
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}
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/*
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* Return a pointer the id 'id' of object of type 'type' in the cache.
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*/
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void *
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ef_ptr(int type, int id)
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{
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struct empfile *ep;
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if (ef_check(type) < 0)
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return NULL;
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ep = &empfile[type];
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if (CANT_HAPPEN(!(ep->flags & EFF_MEM)))
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return NULL;
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if (id < 0 || id >= ep->fids)
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return NULL; /* FIXME can this happen? */
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return ep->cache + ep->size * id;
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}
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/*
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* buffered read. Tries to read a large number of items.
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* This system won't work if item size is > sizeof buffer area.
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*/
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int
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ef_read(int type, int id, void *into)
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{
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struct empfile *ep;
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void *from;
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if (ef_check(type) < 0)
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return 0;
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ep = &empfile[type];
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if (id < 0)
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return 0;
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if (ep->flags & EFF_MEM) {
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if (id >= ep->fids)
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return 0;
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from = ep->cache + (id * ep->size);
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} else {
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if (id >= ep->fids) {
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ep->fids = fsize(ep->fd) / ep->size;
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if (id >= ep->fids)
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return 0;
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}
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if (ep->baseid + ep->cids <= id || ep->baseid > id)
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if (fillcache(ep, id) < 1)
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return 0;
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from = ep->cache + (id - ep->baseid) * ep->size;
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}
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memcpy(into, from, ep->size);
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if (ep->postread)
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ep->postread(id, into);
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return 1;
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}
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/*
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* Fill cache of EP with elements starting at ID.
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* If any were read, return their number.
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* Else return -1 and leave the cache unchanged.
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*/
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static int
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fillcache(struct empfile *ep, int start)
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{
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int n, ret;
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char *p;
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if (CANT_HAPPEN(ep->fd < 0 || !ep->cache))
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return -1;
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if (lseek(ep->fd, start * ep->size, SEEK_SET) == (off_t)-1) {
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logerror("Error seeking %s (%s)", ep->file, strerror(errno));
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return -1;
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}
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p = ep->cache;
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n = ep->csize * ep->size;
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while (n > 0) {
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ret = read(ep->fd, p, n);
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if (ret < 0) {
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if (errno != EAGAIN) {
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logerror("Error reading %s (%s)", ep->file, strerror(errno));
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break;
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}
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} else if (ret == 0) {
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break;
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} else {
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p += ret;
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n -= ret;
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}
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}
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if (p == ep->cache)
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return -1; /* nothing read, old cache still ok */
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ep->baseid = start;
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ep->cids = (p - ep->cache) / ep->size;
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return ep->cids;
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}
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/*
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* Write COUNT elements from BUF to EP, starting at ID.
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* Return 0 on success, -1 on error.
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*/
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static int
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do_write(struct empfile *ep, void *buf, int id, int count)
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{
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int n, ret;
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char *p;
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if (CANT_HAPPEN(ep->fd < 0 || id < 0 || count < 0))
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return -1;
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if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) {
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logerror("Error seeking %s (%s)", ep->file, strerror(errno));
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return -1;
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}
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p = buf;
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n = count * ep->size;
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while (n > 0) {
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ret = write(ep->fd, p, n);
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if (ret < 0) {
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if (errno != EAGAIN) {
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logerror("Error writing %s (%s)", ep->file, strerror(errno));
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return -1;
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}
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} else {
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p += ret;
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n -= ret;
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}
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}
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return 0;
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}
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/*
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* buffered write. Modifies read cache (if applicable)
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* and writes through to disk.
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*/
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int
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ef_write(int type, int id, void *from)
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{
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struct empfile *ep;
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char *to;
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if (ef_check(type) < 0)
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return 0;
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ep = &empfile[type];
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if (id > 65536) {
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/* largest unit id; this may bite us in large games */
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logerror("ef_write: type %d id %d is too large!\n", type, id);
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return 0;
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}
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if (ep->prewrite)
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ep->prewrite(id, from);
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if (CANT_HAPPEN((ep->flags & EFF_MEM) ? id >= ep->fids : id > ep->fids))
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return 0; /* not implemented */
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if (do_write(ep, from, id, 1) < 0)
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return 0;
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if (id >= ep->baseid && id < ep->baseid + ep->cids) {
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/* update the cache if necessary */
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to = ep->cache + (id - ep->baseid) * ep->size;
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memcpy(to, from, ep->size);
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}
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if (id >= ep->fids) {
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/* write beyond end of file extends it, take note */
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ep->fids = id + 1;
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}
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return 1;
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}
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/*
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* Grow the file containing objects of the type 'type' by 'count' objects.
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*/
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int
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ef_extend(int type, int count)
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{
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struct empfile *ep;
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char *tmpobj;
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int cur, max;
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int how;
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int r;
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if (ef_check(type) < 0)
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return 0;
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ep = &empfile[type];
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max = ep->fids + count;
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cur = ep->fids;
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tmpobj = calloc(1, ep->size);
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if ((r = lseek(ep->fd, ep->fids * ep->size, SEEK_SET)) < 0) {
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logerror("ef_extend: %s +#%d lseek(%d, %d, SEEK_SET) -> %d",
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ep->name, count, ep->fd, ep->fids * ep->size, r);
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free(tmpobj);
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return 0;
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}
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for (cur = ep->fids; cur < max; cur++) {
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if (ep->init)
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ep->init(cur, tmpobj);
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if ((r = write(ep->fd, tmpobj, ep->size)) != ep->size) {
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logerror("ef_extend: %s +#%d write(%d, %p, %d) -> %d",
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ep->name, count, ep->fd, tmpobj, ep->size, r);
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free(tmpobj);
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return 0;
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}
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}
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free(tmpobj);
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if (ep->flags & EFF_MEM) {
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/* XXX this will cause problems if there are ef_ptrs (to the
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* old allocated structure) active when we do the re-open */
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how = ep->flags & EFF_OPEN;
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ef_close(type);
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ef_open(type, how);
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} else {
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ep->fids += count;
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}
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return 1;
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}
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/*
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* Mark the cache for the file containing objects of type 'type' as unused.
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*/
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void
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ef_zapcache(int type)
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{
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struct empfile *ep = &empfile[type];
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if ((ep->flags & EFF_MEM) == 0) {
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ep->cids = 0;
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ep->baseid = -1;
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}
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}
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struct castr *
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ef_cadef(int type)
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{
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return empfile[type].cadef;
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}
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int
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ef_nelem(int type)
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{
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return empfile[type].fids;
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}
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int
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ef_flags(int type)
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{
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return empfile[type].flags;
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}
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time_t
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ef_mtime(int type)
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{
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if (empfile[type].fd <= 0)
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return 0;
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return fdate(empfile[type].fd);
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}
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/*
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* Search empfile[0..EF_MAX-1] for element named NAME.
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* Return its index in empfile[] if found, else -1.
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*/
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int
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ef_byname(char *name)
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{
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struct empfile *ef;
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int i;
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int len;
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len = strlen(name);
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for (i = 0; i < EF_MAX; i++) {
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ef = &empfile[i];
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if (strncmp(ef->name, name, min(len, strlen(ef->name))) == 0)
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return i;
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}
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return -1;
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}
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char *
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ef_nameof(int type)
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{
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if (type < 0 || type >= EF_MAX)
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return "bad item type";
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return empfile[type].name;
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}
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int
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ef_check(int type)
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{
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if (type < 0 || type >= EF_MAX) {
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logerror("ef_ptr: bad EF_type %d\n", type);
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return -1;
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}
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return 0;
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}
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int
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ef_ensure_space(int type, int id, int count)
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{
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while (id >= empfile[type].fids) {
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if (!ef_extend(type, count))
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return 0;
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}
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return 1;
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}
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