sys/arch/ia64/stand/common/pager.c

   1 /*      $NetBSD: pager.c,v 1.1 2006/04/07 14:21:29 cherry Exp $ */
   2
   3 /*-
   4  * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28 /*
  29  * Simple paged-output and paged-viewing functions
  30  */
  31
  32 #include <sys/cdefs.h>
  33
  34 #include "lib/libsa/stand.h"
  35 #include "lib/libsa/loadfile.h"
  36
  37 #include <bootstrap.h>
  38
  39 static int      p_maxlines = -1;
  40 static int      p_freelines;
  41
  42 static char *pager_prompt1 = " --more--  <space> page down <enter> line down <q> quit ";
  43 static char *pager_blank   = "                                                        ";
  44
  45 /*
  46  * 'open' the pager
  47  */
  48 void
  49 pager_open(void)
  50 {
  51     int         nlines;
  52     char        *cp, *lp;
  53
  54     nlines = 24;                /* sensible default */
  55     if ((cp = getenv("LINES")) != NULL) {
  56         nlines = strtol(cp, &lp, 0);
  57     }
  58
  59     p_maxlines = nlines - 1;
  60     if (p_maxlines < 1)
  61         p_maxlines = 1;
  62     p_freelines = p_maxlines;
  63 }
  64
  65 /*
  66  * 'close' the pager
  67  */
  68 void
  69 pager_close(void)
  70 {
  71     p_maxlines = -1;
  72 }
  73
  74 /*
  75  * Emit lines to the pager; may not return until the user
  76  * has responded to the prompt.
  77  *
  78  * Will return nonzero if the user enters 'q' or 'Q' at the prompt.
  79  *
  80  * XXX note that this watches outgoing newlines (and eats them), but
  81  *     does not handle wrap detection (req. count of columns).
  82  */
  83
  84 int
  85 pager_output(const char *cp)
  86 {
  87     int         action;
  88
  89     if (cp == NULL)
  90         return(0);
  91
  92     for (;;) {
  93         if (*cp == 0)
  94             return(0);
  95
  96         putchar(*cp);                   /* always emit character */
  97
  98         if (*(cp++) == '\n') {          /* got a newline? */
  99             p_freelines--;
 100             if (p_freelines <= 0) {
 101                 printf("%s", pager_prompt1);
 102                 action = 0;
 103                 while (action == 0) {
 104                     switch(getchar()) {
 105                     case '\r':
 106                     case '\n':
 107                         p_freelines = 1;
 108                         action = 1;
 109                         break;
 110                     case ' ':
 111                         p_freelines = p_maxlines;
 112                         action = 1;
 113                         break;
 114                     case 'q':
 115                     case 'Q':
 116                         action = 2;
 117                         break;
 118                     default:
 119                         break;
 120                     }
 121                 }
 122                 printf("\r%s\r", pager_blank);
 123                 if (action == 2)
 124                     return(1);
 125             }
 126         }
 127     }
 128 }
 129
 130 /*
 131  * Display from (fd).
 132  */
 133 int
 134 pager_file(const char *fname)
 135 {
 136     char        buf[80];
 137     size_t      hmuch;
 138     int         fd;
 139     int         result;
 140
 141     if ((fd = open(fname, O_RDONLY)) == -1) {
 142         printf("can't open '%s': %s\n", fname, strerror(errno));
 143         return(-1);
 144     }
 145
 146     for (;;) {
 147         hmuch = read(fd, buf, sizeof(buf) - 1);
 148         if (hmuch == -1) {
 149             result = -1;
 150             break;
 151         }
 152         if (hmuch == 0) {
 153             result = 0;
 154             break;
 155         }
 156         buf[hmuch] = 0;
 157         if (pager_output(buf)) {
 158             result = 1;
 159             break;
 160         }
 161     }
 162     close(fd);
 163     return(result);
 164 }