This commit was generated by cvs2svn to compensate for changes in r1815,

[bootcd.git] / syslinux / libfat / cache.c

diff --git a/syslinux/libfat/cache.c b/syslinux/libfat/cache.c
new file mode 100644 (file)
index 0000000..378705f
--- /dev/null
+++ b/syslinux/libfat/cache.c
@@ -0,0 +1,70 @@
+#ident "$Id: cache.c,v 1.1 2004/12/15 10:14:39 hpa Exp $"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2004 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);
+  }
+}
+
+
+    
+