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