stdcon_read.c

来自「linux内核」· C语言 代码 · 共 78 行

#ident "$Id$"
/* ----------------------------------------------------------------------- *
 *   
 *   Copyright 2004 H. Peter Anvin - All Rights Reserved
 *
 *   Permission is hereby granted, free of charge, to any person
 *   obtaining a copy of this software and associated documentation
 *   files (the "Software"), to deal in the Software without
 *   restriction, including without limitation the rights to use,
 *   copy, modify, merge, publish, distribute, sublicense, and/or
 *   sell copies of the Software, and to permit persons to whom
 *   the Software is furnished to do so, subject to the following
 *   conditions:
 *   
 *   The above copyright notice and this permission notice shall
 *   be included in all copies or substantial portions of the Software.
 *   
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *   OTHER DEALINGS IN THE SOFTWARE.
 *
 * ----------------------------------------------------------------------- */

/*
 * stdcon_read.c
 *
 * Line-oriented reading from the standard console
 */

#include <errno.h>
#include <string.h>
#include <com32.h>
#include <minmax.h>
#include "file.h"

extern ssize_t __rawcon_read(struct file_info *fp, void *buf, size_t count);

static ssize_t __stdcon_read(struct file_info *fp, void *buf, size_t count)
{
  char *bufp = buf;
  size_t n = 0;
  char ch;

  (void)fp;

  while ( n < count ) {
    if ( fp->i.nbytes ) {
      ch = *bufp++ = *fp->i.datap++;
      fp->i.nbytes--;
      n++;
      if ( ch == '\n' )
	return n;
    } else {
      fp->i.nbytes = __line_input(fp, fp->i.buf, MAXBLOCK,
				    __rawcon_read);
      fp->i.datap = fp->i.buf;

      if ( fp->i.nbytes == 0 )
	return n;
    }
  }

  return n;
}

const struct input_dev dev_stdcon_r = {
  .dev_magic  = __DEV_MAGIC,
  .flags      = __DEV_TTY | __DEV_INPUT,
  .fileflags  = O_RDONLY,
  .read       = __stdcon_read,
  .close      = NULL,
};