#include "file.h"
+#include "directory.h"
+#include "filehdr.h"
+#include "filesys.h"
+#include "lib/debug.h"
+#include "lib/lib.h"
+#include "threads/malloc.h"
+
+bool
+file_open (struct file *file, disk_sector_t hdr_sector)
+{
+ file->hdr = filehdr_read (hdr_sector);
+ file->bounce = malloc (DISK_SECTOR_SIZE);
+ file->pos = 0;
+ if (file->hdr != NULL && file->bounce != NULL)
+ return true;
+ else
+ {
+ filehdr_destroy (file->hdr);
+ free (file->bounce);
+ return false;
+ }
+}
+
+void
+file_close (struct file *file)
+{
+ filehdr_destroy (file->hdr);
+}
-#ifdef FILESYS_STUB
off_t
file_read (struct file *file, void *buffer, off_t size)
{
- int32_t retval = -1;
- filesys_stub_send ("s'read' i i", (int32_t) file, (int32_t) size);
- filesys_stub_receive ("s'read' i", &retval);
- if (retval > 0)
+ off_t bytes_read = file_read_at (file, buffer, size, file->pos);
+ file->pos += bytes_read;
+ return bytes_read;
+}
+
+off_t
+file_read_at (struct file *file, void *buffer_, off_t size,
+ off_t file_ofs)
+{
+ uint8_t *buffer = buffer_;
+ off_t bytes_read = 0;
+
+ while (size > 0)
{
- if (!filesys_stub_receive ("B", buffer, (size_t) retval))
- retval = -1;
+ /* Disk sector to read, starting byte offset within sector. */
+ off_t sector_idx = filehdr_byte_to_sector (file->hdr, file_ofs);
+ int sector_ofs = file_ofs % DISK_SECTOR_SIZE;
+
+ /* Bytes left in file, bytes left in sector, lesser of the two. */
+ off_t file_left = filehdr_length (file->hdr) - file_ofs;
+ int sector_left = DISK_SECTOR_SIZE - sector_ofs;
+ int min_left = file_left < sector_left ? file_left : sector_left;
+
+ /* Number of bytes to actually copy out of this sector. */
+ int chunk_size = size < min_left ? size : min_left;
+ if (chunk_size == 0)
+ break;
+
+ /* Read sector into bounce buffer, then copy into caller's
+ buffer. */
+ disk_read (filesys_disk, sector_idx, file->bounce);
+ memcpy (buffer + bytes_read, file->bounce + sector_ofs, chunk_size);
+
+ /* Advance. */
+ size -= chunk_size;
+ file_ofs += chunk_size;
+ bytes_read += chunk_size;
}
- return retval;
+
+ return bytes_read;
}
off_t
file_write (struct file *file, const void *buffer, off_t size)
{
- int32_t retval = -1;
- filesys_stub_send ("s'write' i B", (int32_t) file, buffer, (size_t) size);
- filesys_stub_receive ("s'write' i", &retval);
- return retval;
+ off_t bytes_written = file_write_at (file, buffer, size, file->pos);
+ file->pos += bytes_written;
+ return bytes_written;
+}
+
+off_t
+file_write_at (struct file *file, const void *buffer_, off_t size,
+ off_t file_ofs)
+{
+ const uint8_t *buffer = buffer_;
+ off_t bytes_written = 0;
+
+ while (size > 0)
+ {
+ /* Starting byte offset within sector to read. */
+ off_t sector_idx = filehdr_byte_to_sector (file->hdr, file_ofs);
+ int sector_ofs = file_ofs % DISK_SECTOR_SIZE;
+
+ /* Bytes left in file, bytes left in sector, lesser of the two. */
+ off_t file_left = filehdr_length (file->hdr) - file_ofs;
+ int sector_left = DISK_SECTOR_SIZE - sector_ofs;
+ int min_left = file_left < sector_left ? file_left : sector_left;
+
+ /* Number of bytes to actually writen into this sector. */
+ int chunk_size = size < min_left ? size : min_left;
+ if (chunk_size == 0)
+ break;
+
+ /* If the sector contains data before or after the chunk
+ we're writing, then we need to read in the sector
+ first. Otherwise we start with a sector of all zeros. */
+ if (sector_ofs > 0 || chunk_size < sector_ofs)
+ disk_read (filesys_disk, sector_idx, file->bounce);
+ else
+ memset (file->bounce, 0, DISK_SECTOR_SIZE);
+ memcpy (file->bounce + sector_ofs, buffer + bytes_written, chunk_size);
+ disk_write (filesys_disk, sector_idx, file->bounce);
+
+ /* Advance. */
+ size -= chunk_size;
+ file_ofs += chunk_size;
+ bytes_written += chunk_size;
+ }
+
+ return bytes_written;
}
off_t
file_length (struct file *file)
{
- int32_t length = -1;
- filesys_stub_send ("s'length' i", (int32_t) file);
- filesys_stub_receive ("s'length' i", &length);
- return length;
+ ASSERT (file != NULL);
+ return filehdr_length (file->hdr);
}
void
-file_seek (struct file *file, off_t pos)
+file_seek (struct file *file, off_t file_ofs)
{
- filesys_stub_send ("s'seek' i i", (int32_t) file, (int32_t) pos);
- filesys_stub_receive ("s'seek'");
+ ASSERT (file != NULL);
+ ASSERT (file_ofs >= 0);
+ file->pos = file_ofs;
}
off_t
file_tell (struct file *file)
{
- int32_t pos = -1;
- filesys_stub_send ("s'tell' i", (int32_t) file);
- filesys_stub_receive ("s'tell'", &pos);
- return pos;
+ ASSERT (file != NULL);
+ return file->pos;
}
-#endif /* FILESYS_STUB */