Start work on filesystem code.

[pintos-anon] / src / filesys / file.c

diff --git a/src/filesys/file.c b/src/filesys/file.c
index b2a4942f56561a6ee3317d06295e98e3ded8001b..e6f282f8062dc2c383f3a540c08b73d0a9628ce7 100644 (file)
--- a/src/filesys/file.c
+++ b/src/filesys/file.c
@@ -1,51 +1,171 @@
 #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) 
+{
+  file->pos = 0;
+  return filehdr_read (&file->hdr, hdr_sector);
+}
+
+void
+file_close (struct file *file) 
+{
+  filehdr_destroy (file);
+}
+
 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 retval = file_read_at (file, buffer, size, file->pos);
+  file->pos += retval;
+  return retval;
+}
+
+off_t
+file_read_at (struct file *file, void *buffer_, off_t size, off_t start) 
+{
+  uint8_t *buffer = buffer_;
+  off_t bytes_read = 0;
+  uint8_t *bounce;
+
+  bounce = malloc (DISK_SECTOR_SIZE);
+  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);
+      int sector_ofs = start % 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;
+
+      /* Number of bytes to actually copy out of this sector. */
+      int chunk_size = file_left < sector_left ? file_left : sector_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);
+
+      /* Advance. */
+      size -= chunk_size;
+      start += chunk_size;
+      bytes_read += chunk_size;
     }
-  return retval;
+  free (bounce);
+
+  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);
+  off_t retval = file_write_at (file, buffer, size, file->pos);
+  file->pos += retval;
   return retval;
 }
 
+off_t
+file_write_at (struct file *file, const void *buffer_, off_t size,
+               off_t start) 
+{
+  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;
+
+      /* 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;
+
+      /* Number of bytes to actually copy out of this sector. */
+      int chunk_size = file_left < sector_left ? file_left : sector_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);
+
+      /* Advance. */
+      size -= chunk_size;
+      start += chunk_size;
+      bytes_read += chunk_size;
+    }
+  free (bounce);
+
+  return bytes_read;
+}
+
 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);
+  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;
 }
 
 void
 file_seek (struct file *file, off_t pos) 
 {
-  filesys_stub_send ("s'seek' i i", (int32_t) file, (int32_t) pos);
-  filesys_stub_receive ("s'seek'");
+  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 ();
 }
 
 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);
+  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;
 }
 #endif /* FILESYS_STUB */