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