contrib/less/ttyin.c

   1 /*
   2  * Copyright (C) 1984-2007  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 about less, or for information on how to
   8  * contact the author, see the README file.
   9  */
  10
  11
  12 /*
  13  * Routines dealing with getting input from the keyboard (i.e. from the user).
  14  */
  15
  16 #include "less.h"
  17 #if OS2
  18 #include "cmd.h"
  19 #include "pckeys.h"
  20 #endif
  21 #if MSDOS_COMPILER==WIN32C
  22 #include "windows.h"
  23 extern char WIN32getch();
  24 static DWORD console_mode;
  25 #endif
  26
  27 public int tty;
  28 extern int sigs;
  29 extern int utf_mode;
  30
  31 /*
  32  * Open keyboard for input.
  33  */
  34         public void
  35 open_getchr()
  36 {
  37 #if MSDOS_COMPILER==WIN32C
  38         /* Need this to let child processes inherit our console handle */
  39         SECURITY_ATTRIBUTES sa;
  40         memset(&sa, 0, sizeof(SECURITY_ATTRIBUTES));
  41         sa.nLength = sizeof(SECURITY_ATTRIBUTES);
  42         sa.bInheritHandle = TRUE;
  43         tty = (int) CreateFile("CONIN$", GENERIC_READ,
  44                         FILE_SHARE_READ, &sa,
  45                         OPEN_EXISTING, 0L, NULL);
  46         GetConsoleMode((HANDLE)tty, &console_mode);
  47         /* Make sure we get Ctrl+C events. */
  48         SetConsoleMode((HANDLE)tty, ENABLE_PROCESSED_INPUT);
  49 #else
  50 #if MSDOS_COMPILER
  51         extern int fd0;
  52         /*
  53          * Open a new handle to CON: in binary mode
  54          * for unbuffered keyboard read.
  55          */
  56          fd0 = dup(0);
  57          close(0);
  58          tty = open("CON", OPEN_READ);
  59 #if MSDOS_COMPILER==DJGPPC
  60         /*
  61          * Setting stdin to binary causes Ctrl-C to not
  62          * raise SIGINT.  We must undo that side-effect.
  63          */
  64         (void) __djgpp_set_ctrl_c(1);
  65 #endif
  66 #else
  67         /*
  68          * Try /dev/tty.
  69          * If that doesn't work, use file descriptor 2,
  70          * which in Unix is usually attached to the screen,
  71          * but also usually lets you read from the keyboard.
  72          */
  73 #if OS2
  74         /* The __open() system call translates "/dev/tty" to "con". */
  75         tty = __open("/dev/tty", OPEN_READ);
  76 #else
  77         tty = open("/dev/tty", OPEN_READ);
  78 #endif
  79         if (tty < 0)
  80                 tty = 2;
  81 #endif
  82 #endif
  83 }
  84
  85 /*
  86  * Close the keyboard.
  87  */
  88         public void
  89 close_getchr()
  90 {
  91 #if MSDOS_COMPILER==WIN32C
  92         SetConsoleMode((HANDLE)tty, console_mode);
  93         CloseHandle((HANDLE)tty);
  94 #endif
  95 }
  96
  97 /*
  98  * Get a character from the keyboard.
  99  */
 100         public int
 101 getchr()
 102 {
 103         char c;
 104         int result;
 105
 106         do
 107         {
 108 #if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
 109                 /*
 110                  * In raw read, we don't see ^C so look here for it.
 111                  */
 112                 flush();
 113 #if MSDOS_COMPILER==WIN32C
 114                 if (ABORT_SIGS())
 115                         return (READ_INTR);
 116                 c = WIN32getch(tty);
 117 #else
 118                 c = getch();
 119 #endif
 120                 result = 1;
 121                 if (c == '\003')
 122                         return (READ_INTR);
 123 #else
 124                 result = iread(tty, &c, sizeof(char));
 125                 if (result == READ_INTR)
 126                         return (READ_INTR);
 127                 if (result < 0)
 128                 {
 129                         /*
 130                          * Don't call error() here,
 131                          * because error calls getchr!
 132                          */
 133                         quit(QUIT_ERROR);
 134                 }
 135 #endif
 136 #if 0 /* allow entering arbitrary hex chars for testing */
 137                 /* ctrl-A followed by two hex chars makes a byte */
 138         {
 139                 int hex_in = 0;
 140                 int hex_value = 0;
 141                 if (c == CONTROL('A'))
 142                 {
 143                         hex_in = 2;
 144                         result = 0;
 145                         continue;
 146                 }
 147                 if (hex_in > 0)
 148                 {
 149                         int v;
 150                         if (c >= '0' && c <= '9')
 151                                 v = c - '0';
 152                         else if (c >= 'a' && c <= 'f')
 153                                 v = c - 'a' + 10;
 154                         else if (c >= 'A' && c <= 'F')
 155                                 v = c - 'A' + 10;
 156                         else
 157                                 hex_in = 0;
 158                         hex_value = (hex_value << 4) | v;
 159                         if (--hex_in > 0)
 160                         {
 161                                 result = 0;
 162                                 continue;
 163                         }
 164                         c = hex_value;
 165                 }
 166         }
 167 #endif
 168                 /*
 169                  * Various parts of the program cannot handle
 170                  * an input character of '\0'.
 171                  * If a '\0' was actually typed, convert it to '\340' here.
 172                  */
 173                 if (c == '\0')
 174                         c = '\340';
 175         } while (result != 1);
 176
 177         return (c & 0xFF);
 178 }