1 /* $NetBSD: pager.c,v 1.2 2009/07/20 04:59:03 kiyohara 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
pager_open(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
pager_close(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
pager_output(const char * cp)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
pager_file(const char * fname)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 }
165