163 lines
3.6 KiB
C
163 lines
3.6 KiB
C
/*-
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* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id$
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*/
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/*
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* Simple paged-output and paged-viewing functions
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*/
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#include "stand.h"
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#include <string.h>
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static int p_maxlines = -1;
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static int p_freelines;
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static char *pager_prompt1 = " --more-- <space> page down <enter> line down <q> quit ";
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static char *pager_blank = " ";
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/*
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* 'open' the pager
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*/
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void
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pager_open(void)
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{
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int nlines;
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char *cp, *lp;
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nlines = 24; /* sensible default */
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if ((cp = getenv("LINES")) != NULL) {
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nlines = strtol(cp, &lp, 0);
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}
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p_maxlines = nlines - 1;
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if (p_maxlines < 1)
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p_maxlines = 1;
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p_freelines = p_maxlines;
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}
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/*
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* 'close' the pager
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*/
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void
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pager_close(void)
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{
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p_maxlines = -1;
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}
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/*
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* Emit lines to the pager; may not return until the user
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* has responded to the prompt.
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*
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* Will return nonzero if the user enters 'q' or 'Q' at the prompt.
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*
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* XXX note that this watches outgoing newlines (and eats them), but
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* does not handle wrap detection (req. count of columns).
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*/
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int
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pager_output(const char *cp)
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{
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int action;
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if (cp == NULL)
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return(0);
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for (;;) {
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if (*cp == 0)
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return(0);
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putchar(*cp); /* always emit character */
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if (*(cp++) == '\n') { /* got a newline? */
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p_freelines--;
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if (p_freelines <= 0) {
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printf(pager_prompt1);
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action = 0;
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while (action == 0) {
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switch(getchar()) {
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case '\r':
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case '\n':
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p_freelines = 1;
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action = 1;
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break;
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case ' ':
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p_freelines = p_maxlines;
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action = 1;
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break;
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case 'q':
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case 'Q':
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action = 2;
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break;
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default:
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break;
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}
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}
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printf("\r%s\r", pager_blank);
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if (action == 2)
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return(1);
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}
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}
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}
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}
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/*
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* Display from (fd).
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*/
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int
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pager_file(char *fname)
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{
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char buf[80];
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size_t hmuch;
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int fd;
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int result;
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if ((fd = open(fname, O_RDONLY)) == -1) {
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printf("can't open '%s': %s\n", fname, strerror(errno));
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return(-1);
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}
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pager_open();
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for (;;) {
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hmuch = read(fd, buf, sizeof(buf) - 1);
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if (hmuch == -1) {
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result = -1;
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break;
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}
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if (hmuch == 0) {
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result = 0;
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break;
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}
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buf[hmuch] = 0;
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if (pager_output(buf)) {
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result = 1;
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break;
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}
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}
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pager_close();
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close(fd);
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return(result);
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}
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