From dbdb8900b5a6b340ac254173febb8fd21e4ae7c5 Mon Sep 17 00:00:00 2001
From: Michael Chisholm <chishm@users.sourceforge.net>
Date: Sat, 30 Sep 2006 15:58:33 +0000
Subject: [PATCH] Added _FAT_fat_linkFreeClusterCleared to clear a cluster when
 it is allocated

---
 source/file_allocation_table.c | 34 ++++++++++++++++++++++++++++++++++
 source/file_allocation_table.h |  4 ++++
 2 files changed, 38 insertions(+)

diff --git a/source/file_allocation_table.c b/source/file_allocation_table.c
index e17774b..ad5ffd5 100644
--- a/source/file_allocation_table.c
+++ b/source/file_allocation_table.c
@@ -31,11 +31,15 @@
 		
 	2006-07-11 - Chishm
 		* Made several fixes related to free clusters, thanks to Loopy
+		
+	2006-10-01 - Chishm
+		* Added _FAT_fat_linkFreeClusterCleared to clear a cluster when it is allocated
 */
 
 
 #include "file_allocation_table.h"
 #include "partition.h"
+#include <string.h>
 
 /*
 Gets the cluster linked from input cluster
@@ -256,6 +260,36 @@ u32 _FAT_fat_linkFreeCluster(PARTITION* partition, u32 cluster) {
 	return firstFree;
 }
 
+/*-----------------------------------------------------------------
+gets the first available free cluster, sets it
+to end of file, links the input cluster to it, clears the new
+cluster to 0 valued bytes, then returns the cluster number
+If an error occurs, return CLUSTER_FREE
+-----------------------------------------------------------------*/
+u32 _FAT_fat_linkFreeClusterCleared (PARTITION* partition, u32 cluster) {
+	u32 newCluster;
+	int i;
+	u8 emptySector[BYTES_PER_READ];
+	
+	// Link the cluster
+	newCluster = _FAT_fat_linkFreeCluster(partition, cluster);
+
+	if (newCluster == CLUSTER_FREE) {
+		return CLUSTER_FREE;
+	}
+
+	// Clear all the sectors within the cluster
+	memset (emptySector, 0, BYTES_PER_READ);
+	for (i = 0; i < partition->sectorsPerCluster; i++) {
+		_FAT_disc_writeSectors (partition->disc, 
+			_FAT_fat_clusterToSector (partition, newCluster) + i,
+			1, emptySector);
+	}
+	
+	return newCluster;
+}
+	
+
 /*-----------------------------------------------------------------
 _FAT_fat_clearLinks
 frees any cluster used by a file
diff --git a/source/file_allocation_table.h b/source/file_allocation_table.h
index 49db983..f67ab10 100644
--- a/source/file_allocation_table.h
+++ b/source/file_allocation_table.h
@@ -28,6 +28,9 @@
 
 	2006-07-11 - Chishm
 		* Original release
+
+	2006-10-01 - Chishm
+		* Added _FAT_fat_linkFreeClusterCleared to clear a cluster when it is allocated
 */
 
 #ifndef _FAT_H
@@ -48,6 +51,7 @@
 u32 _FAT_fat_nextCluster(PARTITION* partition, u32 cluster);
 
 u32 _FAT_fat_linkFreeCluster(PARTITION* partition, u32 cluster);
+u32 _FAT_fat_linkFreeClusterCleared (PARTITION* partition, u32 cluster);
 
 bool _FAT_fat_clearLinks (PARTITION* partition, u32 cluster);