Import of the contiki-2.x development code from the SICS internal CVS server

platform/c64/loader/c64-fs-raw.c

@@ -0,0 +1,205 @@
+/**
+ * \addtogroup c64fs
+ * @{
+ */
+
+/**
+ * \file
+ * "Raw" C64 file system access.
+ * \author Adam Dunkels <adam@dunkels.com>
+ *
+ * This file provides functions that allow reading data from files
+ * without updating the file descriptor pointer. The functions are not
+ * automatically included in the core Contiki code and therefore
+ * application programs that use tham must manually link with this
+ * file.
+ *
+ */
+
+
+/*
+ * Copyright (c) 2003, Adam Dunkels.
+ * All rights reserved. 
+ *
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 2. Redistributions in binary form must reproduce the above
+ *    copyright notice, this list of conditions and the following
+ *    disclaimer in the documentation and/or other materials provided
+ *    with the distribution. 
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior
+ *    written permission.  
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
+ * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+ * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  
+ *
+ * This file is part of the Contiki desktop environment 
+ *
+ * $Id: c64-fs-raw.c,v 1.1 2006/06/17 22:41:26 adamdunkels Exp $
+ *
+ */
+
+#include "c64-fs-raw.h"
+
+#include <string.h>
+
+struct directory_entry {
+  unsigned char type;
+  unsigned char track, sect;
+  unsigned char name[16];
+  unsigned char reltrack, relsect, relreclen;
+  unsigned char unused1, unused2, unused3, unused4;
+  unsigned char tmptrack, tmpsect;
+  unsigned char blockslo, blockshi;
+};
+
+
+extern unsigned char _c64_fs_dirbuf[256];
+extern unsigned char _c64_fs_dirbuftrack, _c64_fs_dirbufsect;
+
+extern unsigned char _c64_fs_filebuf[256];
+extern unsigned char _c64_fs_filebuftrack, _c64_fs_filebufsect;
+
+void _c64_fs_readdirbuf(unsigned char track, unsigned char sect);
+
+
+/*-----------------------------------------------------------------------------------*/
+/**
+ * Read data from a file without updating the file descriptor pointer.
+ *
+ * This function reads data from an open file into a buffer than must
+ * be allocated by the caller, but does not update the file
+ * description pointer like the c64_fs_read() function does.
+ *
+ * \param f A pointer to a file descriptor structure that must have
+ * been opened with c64_fs_open().
+ *
+ * \param buf A pointer to the buffer in which the data should be placed.
+ *
+ * \param len The maxiumum amount of bytes to read.
+ *
+ * \return The number of bytes that actually was read, or 0 if an end
+ * of file was encountered.
+ *
+ */
+/*-----------------------------------------------------------------------------------*/
+int __fastcall__
+c64_fs_read_raw(register struct c64_fs_file *f, char *buf, int len)
+{
+  int i;
+  unsigned char fptr, ftrack, fsect;
+
+  /* Check if current block is already in buffer, and if not read it
+     from disk. */
+  if(_c64_fs_filebuftrack != f->track ||
+     _c64_fs_filebufsect != f->sect) {
+    _c64_fs_filebuftrack = f->track;
+    _c64_fs_filebufsect = f->sect;
+    c64_dio_read_block(_c64_fs_filebuftrack,
+		       _c64_fs_filebufsect, _c64_fs_filebuf);
+  }
+
+  if(_c64_fs_filebuf[0] == 0 &&
+     f->ptr == _c64_fs_filebuf[1]) {
+    return 0; /* EOF */
+  }
+
+  fptr = f->ptr;
+  ftrack = f->track;
+  fsect = f->sect;
+  
+  for(i = 0; i < len; ++i) {
+    *buf = _c64_fs_filebuf[fptr];
+    
+    ++fptr;
+    if(_c64_fs_filebuf[0] == 0) {
+      if(fptr == _c64_fs_filebuf[1]) {
+	/* End of file reached, we return the amount of bytes read so
+	   far. */
+	return i + 1;
+      }
+    } else if(fptr == 0) {
+
+      /* Read new block into buffer and set buffer state
+	 accordingly. */
+      _c64_fs_filebuftrack = ftrack = _c64_fs_filebuf[0];
+      _c64_fs_filebufsect = fsect = _c64_fs_filebuf[1];
+      fptr = 2;
+      c64_dio_read_block(_c64_fs_filebuftrack,
+			 _c64_fs_filebufsect, _c64_fs_filebuf);
+    }
+    
+    ++buf;
+  }
+  return i;
+}
+/*-----------------------------------------------------------------------------------*/
+/**
+ * Move the file descriptior pointer forward in the file.
+ *
+ *
+ * \param f A pointer to a file descriptor structure that must have
+ * been opened with c64_fs_open().
+ *
+ * \param len The number of bytes the pointer should be moved forward.
+ *
+ * \return The number of bytes that the pointer actually was moved, or
+ * 0 if an end of file was encountered.
+ */
+/*-----------------------------------------------------------------------------------*/
+int
+c64_fs_read_next(register struct c64_fs_file *f, int len)
+{
+  int i;
+
+  /* Check if current block is already in buffer, and if not read it
+     from disk. */
+  if(_c64_fs_filebuftrack != f->track ||
+     _c64_fs_filebufsect != f->sect) {
+    _c64_fs_filebuftrack = f->track;
+    _c64_fs_filebufsect = f->sect;
+    c64_dio_read_block(_c64_fs_filebuftrack,
+		       _c64_fs_filebufsect, _c64_fs_filebuf);
+  }
+
+  if(_c64_fs_filebuf[0] == 0 &&
+     f->ptr == _c64_fs_filebuf[1]) {
+    return 0; /* EOF */
+  }
+
+  for(i = 0; i < len; ++i) {
+    
+    ++f->ptr;
+    if(_c64_fs_filebuf[0] == 0) {
+      if(f->ptr == _c64_fs_filebuf[1]) {
+	/* End of file reached, we return the amount of bytes read so
+	   far. */
+	return i + 1;
+      }
+    } else if(f->ptr == 0) {
+      /* Read new block into buffer and set buffer state
+	 accordingly. */
+      _c64_fs_filebuftrack = f->track = _c64_fs_filebuf[0];
+      _c64_fs_filebufsect = f->sect = _c64_fs_filebuf[1];
+      f->ptr = 2;
+      c64_dio_read_block(_c64_fs_filebuftrack,
+			 _c64_fs_filebufsect, _c64_fs_filebuf);
+    }    
+  }
+  return i;
+}
+/*-----------------------------------------------------------------------------------*/
+/** @} */