+/**
+ * Flush file \a fd.
+ * \return 0 if ok, EOF on errors.
+ */
+static int battfs_flush(struct KFile *fd)
+{
+ (void)fd;
+ #warning TODO
+ return 0;
+}
+
+/**
+ * Close file \a fd.
+ * \return 0 if ok, EOF on errors.
+ */
+static int battfs_fileclose(struct KFile *fd)
+{
+ KFileBattFs *fdb = KFILEBATTFS(fd);
+
+ battfs_flush(fd);
+ REMOVE(&fdb->link);
+ return 0;
+}
+
+/**
+ * Read from file \a fd \a size bytes in \a buf.
+ * \return The number of bytes read.
+ */
+static size_t battfs_read(struct KFile *fd, void *_buf, size_t size)
+{
+ KFileBattFs *fdb = KFILEBATTFS(fd);
+ uint8_t *buf = (uint8_t *)_buf;
+
+ size_t total_read = 0;
+ pgoff_t pg_offset;
+ pgaddr_t addr_offset;
+ pgaddr_t read_len;
+
+ size = MIN(size, fd->size - fd->seek_pos);
+
+ while (size)
+ {
+ pg_offset = fd->seek_pos / (fdb->disk->page_size - BATTFS_HEADER_LEN);
+ addr_offset = fd->seek_pos % (fdb->disk->page_size - BATTFS_HEADER_LEN);
+ read_len = MIN(size, (size_t)(fdb->disk->page_size - BATTFS_HEADER_LEN - addr_offset));
+
+ /* Read from disk */
+ if (fdb->disk->read(fdb->disk, fdb->start[pg_offset], addr_offset, buf, read_len) != read_len)
+ {
+ #warning TODO set error?
+ }
+
+ size -= read_len;
+ fd->seek_pos += read_len;
+ total_read += read_len;
+ buf += read_len;
+ }
+ return total_read;
+}
+
+
+/**
+ * Search file \a inode in \a disk using a binary search.
+ * \return pointer to file start in disk->page_array
+ * if file exists, NULL otherwise.
+ */
+static pgcnt_t *findFile(BattFsSuper *disk, inode_t inode)
+{
+ BattFsPageHeader hdr;
+ pgcnt_t first = 0, page, last = disk->page_count -1;
+ fcs_t fcs;
+
+ while (first <= last)
+ {
+ page = (first + last) / 2;
+
+ if (!battfs_readHeader(disk, disk->page_array[page], &hdr))
+ return NULL;
+
+ fcs = computeFcs(&hdr);
+ if (hdr.fcs == fcs && hdr.inode == inode)
+ return (&disk->page_array[page]) - hdr.pgoff;
+ else if (hdr.fcs == fcs && hdr.inode < inode)
+ first = page + 1;
+ else
+ last = page - 1;
+ }
+
+ return NULL;
+}
+
+/**
+ * \return true if file \a inode exists on \a disk, false otherwise.
+ */
+bool battfs_fileExists(BattFsSuper *disk, inode_t inode)
+{
+ return findFile(disk, inode) != NULL;
+}
+
+/**
+ * Count size of file \a inode on \a disk, starting at pointer \a start
+ * in disk->page_array. Size is written in \a size.
+ * \return true if all s ok, false on disk read errors.
+ */
+static bool countFileSize(BattFsSuper *disk, pgcnt_t *start, inode_t inode, file_size_t *size)
+{
+ *size = 0;
+ BattFsPageHeader hdr;
+
+ for (;;)
+ {
+ if (!battfs_readHeader(disk, *start++, &hdr))
+ return false;
+ if (hdr.fcs == computeFcs(&hdr) && hdr.inode == inode)
+ *size += hdr.fill;
+ else
+ return true;
+ }
+}
+