diplodocus.org Git - nmh/blob - docs/historical/mh-6.8.5/miscellany/less-177/cmdbuf.c

   1 /*
   2  * Functions which manipulate the command buffer.
   3  * Used only by command() and related functions.
   4  */
   5
   6 #include "less.h"
   7
   8 extern int erase_char, kill_char;
   9 extern int sc_width;
  10
  11 static char cmdbuf[120];        /* Buffer for holding a multi-char command */
  12 static int cmd_col;             /* Current column of the multi-char command */
  13 static char *cp;                /* Pointer into cmdbuf */
  14
  15 /*
  16  * Reset command buffer (to empty).
  17  */
  18         public void
  19 cmd_reset()
  20 {
  21         cp = cmdbuf;
  22         *cp = '\0';
  23         cmd_col = 0;
  24 }
  25
  26 /*
  27  * How many characters are in the command buffer?
  28  */
  29         public int
  30 len_cmdbuf()
  31 {
  32         return (cp - cmdbuf);
  33 }
  34
  35 /*
  36  * Backspace in the command buffer.
  37  */
  38         public int
  39 cmd_erase()
  40 {
  41         register char *s;
  42
  43         if (cp == cmdbuf)
  44                 /*
  45                  * Backspace past beginning of the string:
  46                  * this usually means abort the command.
  47                  */
  48                 return (1);
  49
  50         --cp;
  51         if (*cp == ESC)
  52                 s = "ESC";
  53         else
  54                 s = prchar(*cp);
  55         while (*s++ != '\0')
  56         {
  57                 backspace();
  58                 cmd_col--;
  59         }
  60         *cp = '\0';
  61         return (0);
  62 }
  63
  64 /*
  65  * Process a single character of a multi-character command, such as
  66  * a number, or the pattern of a search command.
  67  */
  68         public int
  69 cmd_char(c)
  70         int c;
  71 {
  72         char *s;
  73
  74         if (c == erase_char)
  75         {
  76                 if (cmd_erase())
  77                         return (1);
  78         } else if (c == kill_char)
  79         {
  80                 /* {{ Could do this faster, but who cares? }} */
  81                 while (cmd_erase() == 0)
  82                         ;
  83         } else if (cp >= &cmdbuf[sizeof(cmdbuf)-1])
  84         {
  85                 /*
  86                  * No room in the command buffer.
  87                  */
  88                 bell();
  89         } else if (cmd_col >= sc_width-4)
  90         {
  91                 /*
  92                  * No room on the screen.
  93                  * {{ Could get fancy here; maybe shift the displayed
  94                  *    line and make room for more chars, like ksh. }}
  95                  */
  96                 bell();
  97         } else
  98         {
  99                 /*
 100                  * Append the character to the string.
 101                  */
 102                 *cp++ = c;
 103                 *cp = '\0';
 104                 if (c == ESC)
 105                         s = "ESC";
 106                 else
 107                         s = prchar(c);
 108                 putstr(s);
 109                 cmd_col += strlen(s);
 110         }
 111         return (0);
 112 }
 113
 114 /*
 115  * Return the number currently in the command buffer.
 116  */
 117         public int
 118 cmd_int()
 119 {
 120         return (atoi(cmdbuf));
 121 }
 122
 123 /*
 124  * Display a string, usually as a prompt for input into the command buffer.
 125  */
 126         public void
 127 cmd_putstr(s)
 128         char *s;
 129 {
 130         putstr(s);
 131         cmd_col += strlen(s);
 132 }
 133
 134 /*
 135  * Return a pointer to the command buffer.
 136  */
 137         public char *
 138 get_cmdbuf()
 139 {
 140         return (cmdbuf);
 141 }