com32/lib/sys/rawcon_read.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2004-2008 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   Permission is hereby granted, free of charge, to any person
   6  *   obtaining a copy of this software and associated documentation
   7  *   files (the "Software"), to deal in the Software without
   8  *   restriction, including without limitation the rights to use,
   9  *   copy, modify, merge, publish, distribute, sublicense, and/or
  10  *   sell copies of the Software, and to permit persons to whom
  11  *   the Software is furnished to do so, subject to the following
  12  *   conditions:
  13  *
  14  *   The above copyright notice and this permission notice shall
  15  *   be included in all copies or substantial portions of the Software.
  16  *
  17  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  19  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  21  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  22  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  24  *   OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  * ----------------------------------------------------------------------- */
  27
  28 /*
  29  * rawcon_read.c
  30  *
  31  * Character-oriented reading from the console without echo;
  32  * this is a NONBLOCKING device.
  33  */
  34
  35 #include <errno.h>
  36 #include <string.h>
  37 #include <com32.h>
  38 #include <core.h>
  39 #include <minmax.h>
  40 #include "file.h"
  41
  42 /* Global, since it's used by stdcon_read */
  43 ssize_t __rawcon_read(struct file_info *fp, void *buf, size_t count)
  44 {
  45     char *bufp = buf;
  46     size_t n = 0;
  47     static char hi = 0;
  48     static bool hi_key = false;
  49
  50     (void)fp;
  51
  52     while (n < count) {
  53         if (hi_key) {
  54             *bufp++ = hi;
  55             n++;
  56             hi_key = false;
  57             continue;
  58         }
  59
  60         /* Poll */
  61         if (!pollchar())
  62             break;
  63
  64         /* We have data, go get it */
  65         *bufp = getchar(&hi);
  66         if (!*bufp)
  67                 hi_key = true;
  68
  69         bufp++;
  70         n++;
  71     }
  72
  73     return n;
  74 }
  75
  76 const struct input_dev dev_rawcon_r = {
  77     .dev_magic = __DEV_MAGIC,
  78     .flags = __DEV_TTY | __DEV_INPUT,
  79     .fileflags = O_RDONLY,
  80     .read = __rawcon_read,
  81     .close = NULL,
  82     .open = NULL,
  83 };