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Annotation of src/usr.bin/less/ttyin.c, Revision 1.1.1.1

1.1       etheisen    1: /*
                      2:  * Copyright (c) 1984,1985,1989,1994,1995  Mark Nudelman
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms, with or without
                      6:  * modification, are permitted provided that the following conditions
                      7:  * are met:
                      8:  * 1. Redistributions of source code must retain the above copyright
                      9:  *    notice, this list of conditions and the following disclaimer.
                     10:  * 2. Redistributions in binary form must reproduce the above copyright
                     11:  *    notice in the documentation and/or other materials provided with
                     12:  *    the distribution.
                     13:  *
                     14:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
                     15:  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     16:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
                     17:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE
                     18:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
                     19:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
                     20:  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
                     21:  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
                     22:  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
                     23:  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
                     24:  * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
                     25:  */
                     26:
                     27:
                     28: /*
                     29:  * Routines dealing with getting input from the keyboard (i.e. from the user).
                     30:  */
                     31:
                     32: #include "less.h"
                     33:
                     34: static int tty;
                     35:
                     36: /*
                     37:  * Open keyboard for input.
                     38:  */
                     39:        public void
                     40: open_getchr()
                     41: {
                     42: #if MSOFTC || OS2
                     43:        extern int fd0;
                     44:        /*
                     45:         * Open a new handle to CON: in binary mode
                     46:         * for unbuffered keyboard read.
                     47:         */
                     48:         fd0 = dup(0);
                     49:         close(0);
                     50:         tty = OPEN_TTYIN();
                     51: #else
                     52:        /*
                     53:         * Try /dev/tty.
                     54:         * If that doesn't work, use file descriptor 2,
                     55:         * which in Unix is usually attached to the screen,
                     56:         * but also usually lets you read from the keyboard.
                     57:         */
                     58:        tty = OPEN_TTYIN();
                     59:        if (tty < 0)
                     60:                tty = 2;
                     61: #endif
                     62: }
                     63:
                     64: /*
                     65:  * Get a character from the keyboard.
                     66:  */
                     67:        public int
                     68: getchr()
                     69: {
                     70:        char c;
                     71:        int result;
                     72:
                     73:        do
                     74:        {
                     75: #if MSOFTC
                     76:                /*
                     77:                 * In raw read, we don't see ^C so look here for it.
                     78:                 */
                     79:                flush();
                     80:                c = getch();
                     81:                result = 1;
                     82:                if (c == '\003')
                     83:                        return (READ_INTR);
                     84: #else
                     85: #if OS2
                     86:                flush();
                     87:                while (_read_kbd(0, 0, 0) != -1)
                     88:                        continue;
                     89:                if ((c = _read_kbd(0, 1, 0)) == -1)
                     90:                        return (READ_INTR);
                     91:                result = 1;
                     92: #else
                     93:                result = iread(tty, &c, sizeof(char));
                     94:                if (result == READ_INTR)
                     95:                        return (READ_INTR);
                     96:                if (result < 0)
                     97:                {
                     98:                        /*
                     99:                         * Don't call error() here,
                    100:                         * because error calls getchr!
                    101:                         */
                    102:                        quit(QUIT_ERROR);
                    103:                }
                    104: #endif
                    105: #endif
                    106:                /*
                    107:                 * Various parts of the program cannot handle
                    108:                 * an input character of '\0'.
                    109:                 * If a '\0' was actually typed, convert it to '\340' here.
                    110:                 */
                    111:                if (c == '\0')
                    112:                        c = '\340';
                    113:        } while (result != 1);
                    114:
                    115:        return (c & 0377);
                    116: }