X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=fs%2Fbattfs.h;h=f7518ced38104137c03cd96539097890b3a2471c;hb=cf5da75e3f07d6eff61f8e30eb14d15a3dbef17d;hp=1048b66c99f15a86b652b90bab4663407a540e90;hpb=4de4b5e781709be8e01087e0cd434cc3f3dae7ab;p=bertos.git

diff --git a/fs/battfs.h b/fs/battfs.h
index 1048b66c..f7518ced 100644
--- a/fs/battfs.h
+++ b/fs/battfs.h
@@ -43,33 +43,82 @@
 
 #include <cfg/compiler.h> // uintXX_t; STATIC_ASSERT
 #include <cpu/types.h> // CPU_BITS_PER_CHAR
+#include <algo/rotating_hash.h>
 
 typedef uint16_t fill_t;
 typedef fill_t   pgaddr_t;
 typedef uint16_t pgoff_t;
-typedef pgoff_t  mark_t;
+typedef uint32_t mark_t;
+typedef uint8_t  mark_roll_t;
 typedef uint8_t  inode_t;
 typedef uint8_t  seq_t;
-typedef uint16_t fcs_t;
+typedef rotating_t fcs_t;
 
 /**
- * BattFS page header.
- * \note fields order is chosen to comply
- * with CPU alignment.
+ * Size required for free block allocation is at least 1 bit more
+ * than page addressing.
+ */
+STATIC_ASSERT(sizeof(mark_t) > sizeof(pgaddr_t));
+
+/**
+ * BattFS page header, used to represent a page
+ * header in memory.
+ * To see how this is stored on disk:
+ * \see battfs_to_disk
+ * \see disk_to_battfs
  */
 typedef struct BattFsPageHeader
 {
 	inode_t  inode; ///< File inode (file identifier).
 	seq_t    seq;   ///< Page sequence number.
-	mark_t   mark;  ///< Marker used to keep trace of free/used pages.
-	pgoff_t  pgoff; ///< Page offset inside file.
 	fill_t   fill;  ///< Filled bytes in page.
-	uint16_t rfu;   ///< Reserved for future use, 0xFFFF for now.
-	fcs_t    fcs;   ///< FCS (Frame Check Sequence) of the page header.
+	pgoff_t  pgoff; ///< Page offset inside file.
+	mark_t   mark;  ///< Marker used to keep trace of free/used pages.
+
+	/**
+	 * FCS (Frame Check Sequence) of the page header once the page
+	 * as been marked as free.
+	 */
+	fcs_t fcs_free;
+
+	/**
+	 * FCS (Frame Check Sequence) of the page header.
+	 */
+	fcs_t fcs;
 } BattFsPageHeader;
 
-/* Ensure structure has no padding added */
-STATIC_ASSERT(sizeof(BattFsPageHeader) == 12);
+/**
+ * Size of the header once saved on disk.
+ * \see battfs_to_disk
+ * \see disk_to_battfs
+ */
+#define BATTFS_HEADER_LEN 12
+
+/**
+ * Marks for valid pages.
+ * Simply set to 1 all field bits.
+ * \{
+ */
+#define MARK_PAGE_VALID ((1 << (CPU_BITS_PER_CHAR * sizeof(pgaddr_t) + 1)) - 1)
+#define FCS_FREE_VALID  ((1 << (CPU_BITS_PER_CHAR * sizeof(fcs_t))) - 1)
+/* \} */
+
+
+/**
+ * Half-size of free page marker.
+ * Used to keep trace of free marker wrap-arounds.
+ */
+#define MARK_HALF_SIZE (1 << (CPU_BITS_PER_CHAR * sizeof(pgaddr_t) + 1))
+
+/**
+ * Maximum page address.
+ */
+#define MAX_PAGE_ADDR ((1 << (CPU_BITS_PER_CHAR * sizeof(pgaddr_t))) - 1)
+
+/**
+ * Max number of files.
+ */
+#define BATTFS_MAX_FILES (1 << (CPU_BITS_PER_CHAR * sizeof(inode_t)))
 
 /* Fwd decl */
 struct BattFsSuper;
@@ -79,6 +128,11 @@ struct BattFsSuper;
  */
 typedef uint16_t pgcnt_t;
 
+/**
+ * Sentinel used to keep trace of unset pages in disk->page_array.
+ */
+#define PAGE_UNSET_SENTINEL ((1 << (CPU_BITS_PER_CHAR * sizeof(pgcnt_t))) - 1)
+
 /**
  * Type interface for disk init function.
  * \return true if all is ok, false otherwise.
@@ -99,7 +153,7 @@ typedef size_t (*disk_page_read_t) (struct BattFsSuper *d, pgcnt_t page, pgaddr_
  * \a size the lenght to be written.
  * \return the number of bytes written.
  */
-typedef size_t	(*disk_page_write_t) (struct BattFsSuper *d, pgcnt_t page, pgaddr_t addr, void *buf, size_t);
+typedef size_t	(*disk_page_write_t) (struct BattFsSuper *d, pgcnt_t page, pgaddr_t addr, const void *buf, size_t);
 
 /**
  * Type interface for disk page erase function.
@@ -140,7 +194,19 @@ typedef struct BattFsSuper
 	 * Is used by the filesystem to represent
 	 * the entire disk in memory.
 	 */
-	pgcnt_t *page_array;     
+	pgcnt_t *page_array;
+
+    /**
+	 * Lowest free page counter.
+	 * This is the counter of the first availble free page.
+	 */
+	mark_t free_start;
+
+    /**
+	 * Highest free page counter.
+	 * This value is the next to be used to mark a block as free.
+	 */
+	mark_t free_next;
 
 	disk_size_t disk_size;   ///< Size of the disk, in bytes (page_count * page_size).
 	disk_size_t free_bytes;  ///< Free space on the disk.
@@ -148,11 +214,9 @@ typedef struct BattFsSuper
 	/* TODO add other fields. */
 } BattFsSuper;
 
-/**
- * Initialize and mount disk described by
- * \a d.
- * \return false on errors, true otherwise.
- */
 bool battfs_init(struct BattFsSuper *d);
+bool battfs_close(struct BattFsSuper *disk);
+
+bool battfs_writeTestBlock(struct BattFsSuper *disk, pgcnt_t page, inode_t inode, seq_t seq, fill_t fill, pgoff_t pgoff, mark_t mark);
 
 #endif /* FS_BATTFS_H */