contrib/less/ttyin.c

   1 /*
   2  * Copyright (C) 1984-2015  Mark Nudelman
   3  *
   4  * You may distribute under the terms of either the GNU General Public
   5  * License or the Less License, as specified in the README file.
   6  *
   7  * For more information, see the README file.
   8  */
   9
  10
  11 /*
  12  * Routines dealing with getting input from the keyboard (i.e. from the user).
  13  */
  14
  15 #include "less.h"
  16 #if OS2
  17 #include "cmd.h"
  18 #include "pckeys.h"
  19 #endif
  20 #if MSDOS_COMPILER==WIN32C
  21 #include "windows.h"
  22 extern char WIN32getch();
  23 static DWORD console_mode;
  24 #endif
  25
  26 public int tty;
  27 extern int sigs;
  28 extern int utf_mode;
  29
  30 /*
  31  * Open keyboard for input.
  32  */
  33         public void
  34 open_getchr()
  35 {
  36 #if MSDOS_COMPILER==WIN32C
  37         /* Need this to let child processes inherit our console handle */
  38         SECURITY_ATTRIBUTES sa;
  39         memset(&sa, 0, sizeof(SECURITY_ATTRIBUTES));
  40         sa.nLength = sizeof(SECURITY_ATTRIBUTES);
  41         sa.bInheritHandle = TRUE;
  42         tty = (int) CreateFile("CONIN$", GENERIC_READ,
  43                         FILE_SHARE_READ, &sa,
  44                         OPEN_EXISTING, 0L, NULL);
  45         GetConsoleMode((HANDLE)tty, &console_mode);
  46         /* Make sure we get Ctrl+C events. */
  47         SetConsoleMode((HANDLE)tty, ENABLE_PROCESSED_INPUT);
  48 #else
  49 #if MSDOS_COMPILER
  50         extern int fd0;
  51         /*
  52          * Open a new handle to CON: in binary mode
  53          * for unbuffered keyboard read.
  54          */
  55          fd0 = dup(0);
  56          close(0);
  57          tty = open("CON", OPEN_READ);
  58 #if MSDOS_COMPILER==DJGPPC
  59         /*
  60          * Setting stdin to binary causes Ctrl-C to not
  61          * raise SIGINT.  We must undo that side-effect.
  62          */
  63         (void) __djgpp_set_ctrl_c(1);
  64 #endif
  65 #else
  66         /*
  67          * Try /dev/tty.
  68          * If that doesn't work, use file descriptor 2,
  69          * which in Unix is usually attached to the screen,
  70          * but also usually lets you read from the keyboard.
  71          */
  72 #if OS2
  73         /* The __open() system call translates "/dev/tty" to "con". */
  74         tty = __open("/dev/tty", OPEN_READ);
  75 #else
  76         tty = open("/dev/tty", OPEN_READ);
  77 #endif
  78         if (tty < 0)
  79                 tty = 2;
  80 #endif
  81 #endif
  82 }
  83
  84 /*
  85  * Close the keyboard.
  86  */
  87         public void
  88 close_getchr()
  89 {
  90 #if MSDOS_COMPILER==WIN32C
  91         SetConsoleMode((HANDLE)tty, console_mode);
  92         CloseHandle((HANDLE)tty);
  93 #endif
  94 }
  95
  96 /*
  97  * Get a character from the keyboard.
  98  */
  99         public int
 100 getchr()
 101 {
 102         char c;
 103         int result;
 104
 105         do
 106         {
 107 #if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
 108                 /*
 109                  * In raw read, we don't see ^C so look here for it.
 110                  */
 111                 flush();
 112 #if MSDOS_COMPILER==WIN32C
 113                 if (ABORT_SIGS())
 114                         return (READ_INTR);
 115                 c = WIN32getch(tty);
 116 #else
 117                 c = getch();
 118 #endif
 119                 result = 1;
 120                 if (c == '\003')
 121                         return (READ_INTR);
 122 #else
 123                 result = iread(tty, &c, sizeof(char));
 124                 if (result == READ_INTR)
 125                         return (READ_INTR);
 126                 if (result < 0)
 127                 {
 128                         /*
 129                          * Don't call error() here,
 130                          * because error calls getchr!
 131                          */
 132                         quit(QUIT_ERROR);
 133                 }
 134 #endif
 135 #if 0 /* allow entering arbitrary hex chars for testing */
 136                 /* ctrl-A followed by two hex chars makes a byte */
 137         {
 138                 int hex_in = 0;
 139                 int hex_value = 0;
 140                 if (c == CONTROL('A'))
 141                 {
 142                         hex_in = 2;
 143                         result = 0;
 144                         continue;
 145                 }
 146                 if (hex_in > 0)
 147                 {
 148                         int v;
 149                         if (c >= '0' && c <= '9')
 150                                 v = c - '0';
 151                         else if (c >= 'a' && c <= 'f')
 152                                 v = c - 'a' + 10;
 153                         else if (c >= 'A' && c <= 'F')
 154                                 v = c - 'A' + 10;
 155                         else
 156                                 hex_in = 0;
 157                         hex_value = (hex_value << 4) | v;
 158                         if (--hex_in > 0)
 159                         {
 160                                 result = 0;
 161                                 continue;
 162                         }
 163                         c = hex_value;
 164                 }
 165         }
 166 #endif
 167                 /*
 168                  * Various parts of the program cannot handle
 169                  * an input character of '\0'.
 170                  * If a '\0' was actually typed, convert it to '\340' here.
 171                  */
 172                 if (c == '\0')
 173                         c = '\340';
 174         } while (result != 1);
 175
 176         return (c & 0xFF);
 177 }