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Diffstat (limited to 'contrib/syslinux/latest/libfat/cache.c')
-rw-r--r-- | contrib/syslinux/latest/libfat/cache.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/contrib/syslinux/latest/libfat/cache.c b/contrib/syslinux/latest/libfat/cache.c new file mode 100644 index 0000000..85b7ead --- /dev/null +++ b/contrib/syslinux/latest/libfat/cache.c @@ -0,0 +1,65 @@ +/* ----------------------------------------------------------------------- * + * + * 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); + } +} |