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/* ----------------------------------------------------------------------- *
*
* Copyright 2004-2008 H. Peter Anvin - All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
* Boston MA 02111-1307, USA; either version 2 of the License, or
* (at your option) any later version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* cache.c
*
* Simple sector cache
*/
#include <stdlib.h>
#include "libfatint.h"
void *libfat_get_sector(struct libfat_filesystem *fs, libfat_sector_t n)
{
struct libfat_sector *ls;
for (ls = fs->sectors; ls; ls = ls->next) {
if (ls->n == n)
return ls->data; /* Found in cache */
}
/* Not found in cache */
ls = malloc(sizeof(struct libfat_sector));
if (!ls) {
libfat_flush(fs);
ls = malloc(sizeof(struct libfat_sector));
if (!ls)
return NULL; /* Can't allocate memory */
}
if (fs->read(fs->readptr, ls->data, LIBFAT_SECTOR_SIZE, n)
!= LIBFAT_SECTOR_SIZE) {
free(ls);
return NULL; /* I/O error */
}
ls->n = n;
ls->next = fs->sectors;
fs->sectors = ls;
return ls->data;
}
void libfat_flush(struct libfat_filesystem *fs)
{
struct libfat_sector *ls, *lsnext;
lsnext = fs->sectors;
fs->sectors = NULL;
for (ls = lsnext; ls; ls = lsnext) {
lsnext = ls->next;
free(ls);
}
}
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