Index: fat16.c
===================================================================
--- fat16.c (.../sd-reader_release_20060824) (Revision 106)
+++ fat16.c (.../sd-reader_release_20060901) (Revision 106)
@@ -177,6 +177,7 @@
static uint16_t fat16_get_next_cluster(const struct fat16_fs_struct* fs, uint16_t cluster_num);
static uint16_t fat16_append_clusters(const struct fat16_fs_struct* fs, uint16_t cluster_num, uint16_t count);
static uint8_t fat16_free_clusters(const struct fat16_fs_struct* fs, uint16_t cluster_num);
+static uint8_t fat16_terminate_clusters(const struct fat16_fs_struct* fs, uint16_t cluster_num);
static uint8_t fat16_write_dir_entry(const struct fat16_fs_struct* fs, const struct fat16_dir_entry_struct* dir_entry);
static uint8_t fat16_get_fs_free_callback(uint8_t* buffer, uint32_t offset, void* p);
@@ -792,11 +793,12 @@
*
* \note If this function is used for freeing just a part of a cluster
* chain, the new end of the chain is not correctly terminated
- * within the FAT. This has to be done manually afterwards.
+ * within the FAT. Use fat16_terminate_clusters() instead.
*
* \param[in] fs The filesystem on which to operate.
* \param[in] cluster_num The starting cluster of the chain which to free.
* \returns 0 on failure, 1 on success.
+ * \see fat16_terminate_clusters
*/
uint8_t fat16_free_clusters(const struct fat16_fs_struct* fs, uint16_t cluster_num)
{
@@ -845,6 +847,44 @@
}
/**
+ * \ingroup fat16_fs
+ * Frees a part of a cluster chain and correctly terminates the rest.
+ *
+ * Marks the specified cluster as the new end of a cluster chain and
+ * frees all following clusters.
+ *
+ * \param[in] fs The filesystem on which to operate.
+ * \param[in] cluster_num The new end of the cluster chain.
+ * \returns 0 on failure, 1 on success.
+ * \see fat16_free_clusters
+ */
+uint8_t fat16_terminate_clusters(const struct fat16_fs_struct* fs, uint16_t cluster_num)
+{
+#if FAT16_WRITE_SUPPORT
+ if(!fs || cluster_num < 2)
+ return 0;
+
+ /* fetch next cluster before overwriting the cluster entry */
+ uint16_t cluster_num_next = fat16_get_next_cluster(fs, cluster_num);
+
+ /* mark cluster as the last one */
+ uint8_t buffer[2];
+ buffer[0] = FAT16_CLUSTER_LAST_MAX & 0xff;
+ buffer[1] = (FAT16_CLUSTER_LAST_MAX >> 8) & 0xff;
+ if(!fs->partition->device_write(fs->header.fat_offset + 2 * cluster_num, buffer, 2))
+ return 0;
+
+ /* free remaining clusters */
+ if(cluster_num_next)
+ return fat16_free_clusters(fs, cluster_num_next);
+ else
+ return 1;
+#else
+ return 0;
+#endif
+}
+
+/**
* \ingroup fat16_file
* Opens a file on a FAT16 filesystem.
*
@@ -1202,22 +1242,13 @@
break;
/* seek to the next cluster as long as we need the space */
- while(size_new > 0)
+ while(size_new > cluster_size)
{
/* get next cluster of file */
uint16_t cluster_num_next = fat16_get_next_cluster(fd->fs, cluster_num);
if(cluster_num_next)
{
cluster_num = cluster_num_next;
-
- if(size_new <= cluster_size)
- {
- /* file will shrink; get the first cluster to deallocate */
- cluster_num = fat16_get_next_cluster(fd->fs, cluster_num);
- size_new = 0;
- break;
- }
-
size_new -= cluster_size;
}
else
@@ -1226,7 +1257,7 @@
}
}
- if(size_new > 0)
+ if(size_new > cluster_size || cluster_num == 0)
{
/* Allocate new cluster chain and append
* it to the existing one, if available.
@@ -1252,11 +1283,16 @@
if(!fat16_write_dir_entry(fd->fs, &fd->dir_entry))
return 0;
- if(size_new == 0)
+ if(size == 0)
{
- /* free all clusters no longer needed */
+ /* free all clusters of file */
fat16_free_clusters(fd->fs, cluster_num);
}
+ else if(size_new <= cluster_size)
+ {
+ /* free all clusters no longer needed */
+ fat16_terminate_clusters(fd->fs, cluster_num);
+ }
} while(0);
@@ -1741,21 +1777,33 @@
if(!fs)
return 0;
- uint8_t fat[8];
+ uint8_t fat[32];
struct fat16_usage_count_callback_arg count_arg;
count_arg.cluster_count = 0;
count_arg.buffer_size = sizeof(fat);
- if(!fs->partition->device_read_interval(fs->header.fat_offset,
- fat,
- sizeof(fat),
- fs->header.fat_size,
- fat16_get_fs_free_callback,
- &count_arg
- )
- )
- return 0;
+ uint32_t fat_offset = fs->header.fat_offset;
+ uint32_t fat_size = fs->header.fat_size;
+ while(fat_size > 0)
+ {
+ uint16_t length = UINT16_MAX - 1;
+ if(fat_size < length)
+ length = fat_size;
+ if(!fs->partition->device_read_interval(fat_offset,
+ fat,
+ sizeof(fat),
+ length,
+ fat16_get_fs_free_callback,
+ &count_arg
+ )
+ )
+ return 0;
+
+ fat_offset += length;
+ fat_size -= length;
+ }
+
return (uint32_t) count_arg.cluster_count * fs->header.cluster_size;
}
@@ -1766,8 +1814,9 @@
uint8_t fat16_get_fs_free_callback(uint8_t* buffer, uint32_t offset, void* p)
{
struct fat16_usage_count_callback_arg* count_arg = (struct fat16_usage_count_callback_arg*) p;
+ uint8_t buffer_size = count_arg->buffer_size;
- for(uint8_t i = 0; i < count_arg->buffer_size; i += 2)
+ for(uint8_t i = 0; i < buffer_size; i += 2)
{
if((((uint16_t) buffer[1] << 8) | ((uint16_t) buffer[0] << 0)) == FAT16_CLUSTER_FREE)
++(count_arg->cluster_count);
Index: main.c
===================================================================
--- main.c (.../sd-reader_release_20060824) (Revision 106)
+++ main.c (.../sd-reader_release_20060901) (Revision 106)
@@ -101,12 +101,12 @@
*
*
* | FAT16 (read-only) |
- * 3722 |
+ * 3828 |
* 0 |
*
*
* | FAT16 (read-write) |
- * 7024 |
+ * 7298 |
* 0 |
*
*
Index: ChangeLog
===================================================================
--- ChangeLog (.../sd-reader_release_20060824) (Revision 106)
+++ ChangeLog (.../sd-reader_release_20060901) (Revision 106)
@@ -1,4 +1,8 @@
+2006-09-01 sd-reader
+ * Fix shortening files.
+ * Fix free disk space calculation.
+
2006-08-24 sd-reader
* Improve sleep handling.
* Display extended card information on boot and