1 files changed, 168 insertions, 0 deletions
diff --git a/libc/bios/fileops.c b/libc/bios/fileops.c
new file mode 100644
index 0000000..5c71a37
--- /dev/null
+++ b/libc/bios/fileops.c
@@ -0,0 +1,168 @@
+
+#include <bios.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include "io.h"
+#include "rawio.h"
+
+static int op_open();
+static int op_close();
+static int op_read();
+static int op_write();
+static long op_lseek();
+
+int
+__fileops(cmd, fd, buf, len)
+int cmd, fd, len;
+char * buf;
+{ 
+   switch(cmd)
+   {
+   case CMD_OPEN:  return op_open(buf, fd, len);
+   case CMD_READ:  return op_read(fd, buf, len);
+/*
+   case CMD_WRITE: return op_write(fd, buf, len);
+   case CMD_LSEEK: rv = op_lseek(fd, *(long*)buf, len);
+                   (*(long*)buf) = rv;
+		   if( rv == -1 ) return -1;
+		   else return 0;
+ */
+   case CMD_CLOSE: return op_close(fd);
+   }
+
+   errno=EINVAL;
+   return -1;
+}
+
+#define MAX_OPEN_FILES 5
+ioblock _iob[MAX_OPEN_FILES];
+
+static int
+op_read(fd,buf,len)
+int fd,len;
+char * buf;
+{
+   ioblock* cur = &_iob[fd];
+   int amount_read = 0;
+   int amount_left_in_buffer;
+   int amount_to_copy;
+
+   if (fd >= MAX_OPEN_FILES || _iob[fd].block_read == 0)
+   {
+      errno = EBADF;
+      return -1;
+   }
+
+   while (len > 0)
+   {
+      /* pull in next block as required */
+      if (cur->amount_left <= 0)
+      {
+         int read_len = cur->block_read(cur,
+                                        cur->buffer,
+                                        (long) cur->offset / sizeof(cur->buffer)
+                                       );
+#ifdef DEBUG
+         fprintf(stderr, "br: returned %d\n", read_len);
+#endif
+         if (read_len <= 0)
+            break;
+         cur->amount_left = read_len;
+      }
+      if (cur->amount_left > len)
+         amount_to_copy = len;
+      else
+         amount_to_copy = cur->amount_left;
+
+#ifdef DEBUG
+      fprintf(stderr, "r: len=%d, amount_left=%ld, offset=%ld, buf=%x\n",
+              len, cur->amount_left, cur->offset,
+              (int) cur->buffer[cur->offset % sizeof(cur->buffer)]);
+#endif
+      memcpy(buf,
+             &cur->buffer[cur->offset % sizeof(cur->buffer)],
+             amount_to_copy);
+      amount_read += amount_to_copy;
+      len -= amount_to_copy;
+      cur->offset += amount_to_copy;
+      buf += amount_to_copy;
+      cur->amount_left -= amount_to_copy;
+   }
+   return amount_read;
+}
+
+/****************************************************************************/
+
+static int
+op_open(name, flags, mode)
+char * name;
+int flags, mode;
+{
+   int fd;
+   ioblock* cur;
+
+   /*
+    * discover whether the iob has been initialised or not
+    */
+   if (_iob[0].flags == 0)
+   {
+      _iob[0].flags = O_RDONLY;
+      _iob[1].flags = O_WRONLY;
+      _iob[2].flags = O_WRONLY;
+   }
+   /*
+    * discover next free iob
+    */
+   for (fd = 3; fd < MAX_OPEN_FILES; ++fd)
+   {
+      if (_iob[fd].block_read == NULL && _iob[fd].block_write == NULL)
+         break;
+   }
+   if (fd >= MAX_OPEN_FILES)
+   {
+      errno = EMFILE;   /* too many open files */
+      return -1;
+   }
+
+   /*
+    * try and find the file
+    */
+   cur = &_iob[fd];
+   if (fsdos_open_file(cur, name, flags, mode) >= 0)
+   {
+       cur->amount_left = 0;
+       cur->offset = 0;
+       return fd;
+   }
+   cur->block_read = NULL;      /* ensure that the file is closed */
+   cur->block_write = NULL;
+   errno = ENOENT;
+   return -1;
+}
+
+/****************************************************************************/
+
+static int
+op_close(fd)
+int fd;
+{
+   if (fd >= MAX_OPEN_FILES || _iob[0].flags == 0)
+   {
+      errno = EBADF;
+      return -1;
+   }
+   else
+   {
+       ioblock* cur = &_iob[fd];
+       cur->close(cur);
+       cur->block_read = NULL;
+       cur->block_write = NULL;
+       cur->close = NULL;
+       cur->flags = 0;
+       return 0;
+   }
+}
+
+/****************************************************************************/
+