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 <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include "stand.h" 34 #include <string.h> 35 36 static int p_maxlines = -1; 37 static int p_freelines; 38 39 static char *pager_prompt1 = " --more-- <space> page down <enter> line down <q> quit "; 40 static char *pager_blank = " "; 41 42 /* 43 * 'open' the pager 44 */ 45 void 46 pager_open(void) 47 { 48 int nlines; 49 char *cp, *lp; 50 51 nlines = 24; /* sensible default */ 52 if ((cp = getenv("LINES")) != NULL) { 53 nlines = strtol(cp, &lp, 0); 54 } 55 56 p_maxlines = nlines - 1; 57 if (p_maxlines < 1) 58 p_maxlines = 1; 59 p_freelines = p_maxlines; 60 } 61 62 /* 63 * 'close' the pager 64 */ 65 void 66 pager_close(void) 67 { 68 p_maxlines = -1; 69 } 70 71 /* 72 * Emit lines to the pager; may not return until the user 73 * has responded to the prompt. 74 * 75 * Will return nonzero if the user enters 'q' or 'Q' at the prompt. 76 * 77 * XXX note that this watches outgoing newlines (and eats them), but 78 * does not handle wrap detection (req. count of columns). 79 */ 80 81 int 82 pager_output(const char *cp) 83 { 84 int action; 85 86 if (cp == NULL) 87 return(0); 88 89 for (;;) { 90 if (*cp == 0) 91 return(0); 92 93 putchar(*cp); /* always emit character */ 94 95 if (*(cp++) == '\n') { /* got a newline? */ 96 p_freelines--; 97 if (p_freelines <= 0) { 98 printf("%s", pager_prompt1); 99 action = 0; 100 while (action == 0) { 101 switch(getchar()) { 102 case '\r': 103 case '\n': 104 p_freelines = 1; 105 action = 1; 106 break; 107 case ' ': 108 p_freelines = p_maxlines; 109 action = 1; 110 break; 111 case 'q': 112 case 'Q': 113 action = 2; 114 break; 115 default: 116 break; 117 } 118 } 119 printf("\r%s\r", pager_blank); 120 if (action == 2) 121 return(1); 122 } 123 } 124 } 125 } 126 127 /* 128 * Display from (fd). 129 */ 130 int 131 pager_file(const char *fname) 132 { 133 char buf[80]; 134 size_t hmuch; 135 int fd; 136 int result; 137 138 if ((fd = open(fname, O_RDONLY)) == -1) { 139 printf("can't open '%s': %s\n", fname, strerror(errno)); 140 return(-1); 141 } 142 143 for (;;) { 144 hmuch = read(fd, buf, sizeof(buf) - 1); 145 if (hmuch == -1) { 146 result = -1; 147 break; 148 } 149 if (hmuch == 0) { 150 result = 0; 151 break; 152 } 153 buf[hmuch] = 0; 154 if (pager_output(buf)) { 155 result = 1; 156 break; 157 } 158 } 159 close(fd); 160 return(result); 161 } 162