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 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 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 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 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