-#include "file.h"
-
-#ifdef FILESYS_STUB
-#include "debug.h"
-#include "filesys-stub.h"
-#include "lib.h"
-#include "malloc.h"
-
-bool
-file_open (struct file *file, const char *name)
-{
- struct dir dir;
- disk_sector_no hdr_sector;
- bool success = false;
-
- dir_init (&dir, NUM_DIR_ENTRIES);
- dir_read (&dir, &root_dir_file);
- if (dir_lookup (&dir, name, &hdr_sector))
- success = file_open_sector (file, hdr_sector);
-
- dir_destroy (&dir);
- return success;
-}
-
-bool
-file_open_sector (struct file *file, disk_sector_no hdr_sector)
+#include "filesys/file.h"
+#include <debug.h>
+#include <string.h>
+#include "filesys/directory.h"
+#include "filesys/inode.h"
+#include "filesys/filesys.h"
+#include "threads/malloc.h"
+
+/* An open file. */
+struct file
+ {
+ struct inode *inode; /* File's inode. */
+ uint8_t *bounce; /* Bounce buffer for reads and writes. */
+ off_t pos; /* Current position. */
+ };
+
+/* Opens and returns the file whose inode is in sector
+ INODE_SECTOR. Returns a null pointer if unsuccessful. */
+struct file *
+file_open (disk_sector_t inode_sector)
{
+ struct file *file = calloc (1, sizeof *file);
+ if (file == NULL)
+ return NULL;
+
+ file->inode = inode_open (inode_sector);
+ file->bounce = malloc (DISK_SECTOR_SIZE);
file->pos = 0;
- return filehdr_read (&file->hdr, hdr_sector);
+ if (file->inode == NULL || file->bounce == NULL)
+ {
+ inode_close (file->inode);
+ free (file->bounce);
+ return NULL;
+ }
+
+ return file;
}
+/* Closes FILE. */
void
file_close (struct file *file)
{
- filehdr_destroy (file);
+ if (file == NULL)
+ return;
+
+ inode_close (file->inode);
+ free (file->bounce);
}
+/* Reads SIZE bytes from FILE into BUFFER,
+ starting at the file's current position,
+ and advances the current position.
+ Returns the number of bytes actually read,
+ which may be less than SIZE if end of file is reached. */
off_t
file_read (struct file *file, void *buffer, off_t size)
{
- off_t retval = file_read_at (file, buffer, size, file->pos);
- file->pos += retval;
- return retval;
+ off_t bytes_read = file_read_at (file, buffer, size, file->pos);
+ file->pos += bytes_read;
+ return bytes_read;
}
+/* Reads SIZE bytes from FILE into BUFFER,
+ starting at offset FILE_OFS in the file.
+ The file's current position is unaffected
+ Returns the number of bytes actually read,
+ which may be less than SIZE if end of file is reached. */
off_t
-file_read_at (struct file *file, void *buffer_, off_t size, off_t start)
+file_read_at (struct file *file, void *buffer_, off_t size,
+ off_t file_ofs)
{
uint8_t *buffer = buffer_;
off_t bytes_read = 0;
- uint8_t *bounce;
- bounce = malloc (DISK_SECTOR_SIZE);
while (size > 0)
{
/* Disk sector to read, starting byte offset within sector. */
- off_t sector_idx = filehdr_byte_to_sector (file->hdr);
- int sector_ofs = start % DISK_SECTOR_SIZE;
+ off_t sector_idx = inode_byte_to_sector (file->inode, file_ofs);
+ int sector_ofs = file_ofs % DISK_SECTOR_SIZE;
- /* Bytes left in file, bytes left in sector. */
- off_t file_left = filehdr_size (file->hdr) - start;
- off_t sector_left = DISK_SECTOR_SIZE - sector_ofs;
+ /* Bytes left in file, bytes left in sector, lesser of the two. */
+ off_t file_left = inode_length (file->inode) - 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 = file_left < sector_left ? file_left : sector_left;
+ 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 (disk, sector_idx, bounce);
- memcpy (buffer + bytes_read, bounce + sector_ofs, chunk_size);
+ disk_read (filesys_disk, sector_idx, file->bounce);
+ memcpy (buffer + bytes_read, file->bounce + sector_ofs, chunk_size);
/* Advance. */
size -= chunk_size;
- start += chunk_size;
+ file_ofs += chunk_size;
bytes_read += chunk_size;
}
- free (bounce);
return bytes_read;
}
+/* Writes SIZE bytes from BUFFER into FILE,
+ starting at the file's current position,
+ and advances the current position.
+ Returns the number of bytes actually written,
+ which may be less than SIZE if end of file is reached.
+ (Normally we'd grow the file in that case, but file growth is
+ not yet implemented.) */
off_t
file_write (struct file *file, const void *buffer, off_t size)
{
- off_t retval = file_write_at (file, buffer, size, file->pos);
- file->pos += retval;
- return retval;
+ off_t bytes_written = file_write_at (file, buffer, size, file->pos);
+ file->pos += bytes_written;
+ return bytes_written;
}
+/* Writes SIZE bytes from BUFFER into FILE,
+ starting at offset FILE_OFS in the file.
+ The file's current position is unaffected
+ Returns the number of bytes actually written,
+ which may be less than SIZE if end of file is reached.
+ (Normally we'd grow the file in that case, but file growth is
+ not yet implemented.) */
off_t
file_write_at (struct file *file, const void *buffer_, off_t size,
- off_t start)
+ off_t file_ofs)
{
- uint8_t *buffer = buffer_;
- off_t bytes_read = 0;
- uint8_t *bounce;
+ const uint8_t *buffer = buffer_;
+ off_t bytes_written = 0;
- bounce = malloc (DISK_SECTOR_SIZE);
while (size > 0)
{
- /* Disk sector to read, starting byte offset within sector. */
- off_t sector_idx = filehdr_byte_to_sector (file->hdr);
- int sector_ofs = start % DISK_SECTOR_SIZE;
+ /* Starting byte offset within sector to read. */
+ off_t sector_idx = inode_byte_to_sector (file->inode, file_ofs);
+ int sector_ofs = file_ofs % DISK_SECTOR_SIZE;
- /* Bytes left in file, bytes left in sector. */
- off_t file_left = filehdr_size (file->hdr) - start;
- off_t sector_left = DISK_SECTOR_SIZE - sector_ofs;
+ /* Bytes left in file, bytes left in sector, lesser of the two. */
+ off_t file_left = inode_length (file->inode) - 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 = 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;
- /* Read sector into bounce buffer, then copy into caller's
- buffer. */
- disk_read (disk, sector_idx, bounce);
- memcpy (buffer + bytes_read, bounce + sector_ofs, chunk_size);
+ /* 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;
- start += chunk_size;
- bytes_read += chunk_size;
+ file_ofs += chunk_size;
+ bytes_written += chunk_size;
}
- free (bounce);
- return bytes_read;
+ return bytes_written;
}
+/* Returns the size of FILE in bytes. */
off_t
file_length (struct file *file)
{
- int32_t length;
-
- filesys_stub_lock ();
- filesys_stub_put_string ("length");
- filesys_stub_put_file (file);
- filesys_stub_match_string ("length");
- length = filesys_stub_get_int32 ();
- filesys_stub_unlock ();
-
- return length;
+ ASSERT (file != NULL);
+ return inode_length (file->inode);
}
+/* Sets the current position in FILE to an offset of FILE_OFS
+ bytes from the start of the file. */
void
-file_seek (struct file *file, off_t pos)
+file_seek (struct file *file, off_t file_ofs)
{
- filesys_stub_lock ();
- filesys_stub_put_string ("seek");
- filesys_stub_put_file (file);
- filesys_stub_put_uint32 (pos);
- filesys_stub_match_string ("seek");
- filesys_stub_unlock ();
+ ASSERT (file != NULL);
+ ASSERT (file_ofs >= 0);
+ file->pos = file_ofs;
}
+/* Returns the current position in FILE as a byte offset from the
+ start of the file. */
off_t
file_tell (struct file *file)
{
- int32_t pos;
-
- filesys_stub_lock ();
- filesys_stub_put_string ("tell");
- filesys_stub_put_file (file);
- filesys_stub_match_string ("tell");
- pos = filesys_stub_get_int32 ();
- filesys_stub_unlock ();
-
- return pos;
+ ASSERT (file != NULL);
+ return file->pos;
}
-#endif /* FILESYS_STUB */
projects / pintos-anon / blobdiff