busybox/util-linux/more.c

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/* vi: set sw=4 ts=4: */
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/*
* Mini more implementation for busybox
*
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* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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*
* Latest version blended together by Erik Andersen <andersen@codepoet.org>,
* based on the original more implementation by Bruce, and code from the
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* Debian boot-floppies team.
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*
* Termios corrects by Vladimir Oleynik <dzo@simtreas.ru>
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*
* Licensed under GPLv2 or later, see file License in this tarball for details.
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*/
#include "busybox.h"
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#if ENABLE_FEATURE_USE_TERMIOS
static int cin_fileno;
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#include <termios.h>
#define setTermSettings(fd, argp) tcsetattr(fd, TCSANOW, argp)
#define getTermSettings(fd, argp) tcgetattr(fd, argp);
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static struct termios initial_settings, new_settings;
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static void set_tty_to_initial_mode(void)
{
setTermSettings(cin_fileno, &initial_settings);
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}
static void gotsig(int sig)
{
putchar('\n');
exit(EXIT_FAILURE);
}
#endif /* FEATURE_USE_TERMIOS */
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int more_main(int argc, char **argv);
int more_main(int argc, char **argv)
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{
int c, lines, input = 0;
int please_display_more_prompt = 0;
struct stat st;
FILE *file;
FILE *cin;
int len, page_height;
int terminal_width;
int terminal_height;
argv++;
/* Another popular pager, most, detects when stdout
* is not a tty and turns into cat. This makes sense. */
if (!isatty(STDOUT_FILENO))
return bb_cat(argv);
cin = fopen(CURRENT_TTY, "r");
if (!cin)
return bb_cat(argv);
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#if ENABLE_FEATURE_USE_TERMIOS
cin_fileno = fileno(cin);
getTermSettings(cin_fileno, &initial_settings);
new_settings = initial_settings;
new_settings.c_lflag &= ~ICANON;
new_settings.c_lflag &= ~ECHO;
new_settings.c_cc[VMIN] = 1;
new_settings.c_cc[VTIME] = 0;
setTermSettings(cin_fileno, &new_settings);
atexit(set_tty_to_initial_mode);
signal(SIGINT, gotsig);
signal(SIGQUIT, gotsig);
signal(SIGTERM, gotsig);
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#endif
please_display_more_prompt = 2;
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do {
file = stdin;
if (*argv) {
file = fopen_or_warn(*argv, "r");
if (!file)
continue;
}
st.st_size = 0;
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fstat(fileno(file), &st);
please_display_more_prompt &= ~1;
/* never returns w, h <= 1 */
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get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
terminal_width -= 1;
terminal_height -= 1;
len = 0;
lines = 0;
page_height = terminal_height;
while ((c = getc(file)) != EOF) {
if ((please_display_more_prompt & 3) == 3) {
len = printf("--More-- ");
if (/*file != stdin &&*/ st.st_size > 0) {
len += printf("(%d%% of %"OFF_FMT"d bytes)",
(int) (ftello(file)*100 / st.st_size),
st.st_size);
}
fflush(stdout);
/*
* We've just displayed the "--More--" prompt, so now we need
* to get input from the user.
*/
input = getc(cin);
#if !ENABLE_FEATURE_USE_TERMIOS
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printf("\033[A"); /* up cursor */
#endif
/* Erase the "More" message */
printf("\r%*s\r", len, "");
len = 0;
lines = 0;
/* Bottom line on page will become top line
* after one page forward. Thus -1: */
page_height = terminal_height - 1;
please_display_more_prompt &= ~1;
if (input == 'q')
goto end;
}
/*
* There are two input streams to worry about here:
*
* c : the character we are reading from the file being "mored"
* input : a character received from the keyboard
*
* If we hit a newline in the _file_ stream, we want to test and
* see if any characters have been hit in the _input_ stream. This
* allows the user to quit while in the middle of a file.
*/
if (c == '\n') {
/* increment by just one line if we are at
* the end of this line */
if (input == '\n')
please_display_more_prompt |= 1;
/* Adjust the terminal height for any overlap, so that
* no lines get lost off the top. */
if (len >= terminal_width) {
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int quot, rem;
quot = len / terminal_width;
rem = len - (quot * terminal_width);
page_height -= (quot - 1);
if (rem)
page_height--;
}
if (++lines >= page_height) {
please_display_more_prompt |= 1;
}
len = 0;
}
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/*
* If we just read a newline from the file being 'mored' and any
* key other than a return is hit, scroll by one page
*/
putc(c, stdout);
/* My small mind cannot fathom tabs, backspaces,
* and UTF-8 */
len++;
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}
fclose(file);
fflush(stdout);
} while (*argv && *++argv);
end:
return 0;
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}