mirror of
https://github.com/sheumann/hush.git
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236 lines
6.6 KiB
C
236 lines
6.6 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini more implementation for busybox
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*
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* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
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* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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*
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* Latest version blended together by Erik Andersen <andersen@codepoet.org>,
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* based on the original more implementation by Bruce, and code from the
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* Debian boot-floppies team.
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*
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* Termios corrects by Vladimir Oleynik <dzo@simtreas.ru>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//config:config MORE
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//config: bool "more"
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//config: default y
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//config: help
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//config: more is a simple utility which allows you to read text one screen
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//config: sized page at a time. If you want to read text that is larger than
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//config: the screen, and you are using anything faster than a 300 baud modem,
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//config: you will probably find this utility very helpful. If you don't have
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//config: any need to reading text files, you can leave this disabled.
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//applet:IF_MORE(APPLET(more, BB_DIR_BIN, BB_SUID_DROP))
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//kbuild:lib-$(CONFIG_MORE) += more.o
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//usage:#define more_trivial_usage
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//usage: "[FILE]..."
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//usage:#define more_full_usage "\n\n"
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//usage: "View FILE (or stdin) one screenful at a time"
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//usage:
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//usage:#define more_example_usage
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//usage: "$ dmesg | more\n"
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#include "libbb.h"
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#include "common_bufsiz.h"
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/* Support for FEATURE_USE_TERMIOS */
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struct globals {
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int cin_fileno;
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struct termios initial_settings;
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struct termios new_settings;
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} FIX_ALIASING;
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#define G (*(struct globals*)bb_common_bufsiz1)
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#define initial_settings (G.initial_settings)
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#define new_settings (G.new_settings )
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#define cin_fileno (G.cin_fileno )
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#define INIT_G() do { setup_common_bufsiz(); } while (0)
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#define setTermSettings(fd, argp) \
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do { \
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if (ENABLE_FEATURE_USE_TERMIOS) \
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tcsetattr(fd, TCSANOW, argp); \
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} while (0)
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#define getTermSettings(fd, argp) tcgetattr(fd, argp)
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static void gotsig(int sig UNUSED_PARAM)
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{
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/* bb_putchar_stderr doesn't use stdio buffering,
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* therefore it is safe in signal handler */
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bb_putchar_stderr('\n');
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setTermSettings(cin_fileno, &initial_settings);
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_exit(EXIT_FAILURE);
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}
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#define CONVERTED_TAB_SIZE 8
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int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int more_main(int argc UNUSED_PARAM, char **argv)
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{
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int c = c; /* for compiler */
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int lines;
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int input = 0;
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int spaces = 0;
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int please_display_more_prompt;
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struct stat st;
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FILE *file;
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FILE *cin;
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int len;
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unsigned terminal_width;
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unsigned terminal_height;
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INIT_G();
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/* Parse options */
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/* Accepted but ignored: */
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/* -d Display help instead of ringing bell is pressed */
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/* -f Count logical lines (IOW: long lines are not folded) */
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/* -l Do not pause after any line containing a ^L (form feed) */
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/* -s Squeeze blank lines into one */
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/* -u Suppress underlining */
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getopt32(argv, "dflsu");
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argv += optind;
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/* Another popular pager, most, detects when stdout
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* is not a tty and turns into cat. This makes sense. */
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if (!isatty(STDOUT_FILENO))
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return bb_cat(argv);
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cin = fopen_for_read(CURRENT_TTY);
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if (!cin)
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return bb_cat(argv);
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if (ENABLE_FEATURE_USE_TERMIOS) {
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cin_fileno = fileno(cin);
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getTermSettings(cin_fileno, &initial_settings);
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new_settings = initial_settings;
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new_settings.c_lflag &= ~(ICANON | ECHO);
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new_settings.c_cc[VMIN] = 1;
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new_settings.c_cc[VTIME] = 0;
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setTermSettings(cin_fileno, &new_settings);
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bb_signals(0
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+ (1 << SIGINT)
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+ (1 << SIGQUIT)
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+ (1 << SIGTERM)
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, gotsig);
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}
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do {
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file = stdin;
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if (*argv) {
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file = fopen_or_warn(*argv, "r");
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if (!file)
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continue;
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}
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st.st_size = 0;
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fstat(fileno(file), &st);
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please_display_more_prompt = 0;
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/* never returns w, h <= 1 */
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get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height);
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terminal_height -= 1;
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len = 0;
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lines = 0;
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while (spaces || (c = getc(file)) != EOF) {
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int wrap;
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if (spaces)
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spaces--;
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loop_top:
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if (input != 'r' && please_display_more_prompt) {
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len = printf("--More-- ");
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if (st.st_size != 0) {
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uoff_t d = (uoff_t)st.st_size / 100;
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if (d == 0)
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d = 1;
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len += printf("(%u%% of %"OFF_FMT"u bytes)",
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(int) ((uoff_t)ftello(file) / d),
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st.st_size);
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}
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fflush_all();
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/*
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* We've just displayed the "--More--" prompt, so now we need
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* to get input from the user.
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*/
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for (;;) {
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input = getc(cin);
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input = tolower(input);
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if (!ENABLE_FEATURE_USE_TERMIOS)
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printf("\033[A"); /* cursor up */
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/* Erase the last message */
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printf("\r%*s\r", len, "");
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/* Due to various multibyte escape
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* sequences, it's not ok to accept
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* any input as a command to scroll
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* the screen. We only allow known
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* commands, else we show help msg. */
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if (input == ' ' || input == '\n' || input == 'q' || input == 'r')
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break;
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len = printf("(Enter:next line Space:next page Q:quit R:show the rest)");
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}
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len = 0;
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lines = 0;
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please_display_more_prompt = 0;
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if (input == 'q')
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goto end;
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/* The user may have resized the terminal.
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* Re-read the dimensions. */
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if (ENABLE_FEATURE_USE_TERMIOS) {
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get_terminal_width_height(cin_fileno, &terminal_width, &terminal_height);
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terminal_height -= 1;
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}
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}
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/* Crudely convert tabs into spaces, which are
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* a bajillion times easier to deal with. */
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if (c == '\t') {
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spaces = ((unsigned)~len) % CONVERTED_TAB_SIZE;
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c = ' ';
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}
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/*
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* There are two input streams to worry about here:
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*
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* c : the character we are reading from the file being "mored"
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* input: a character received from the keyboard
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*
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* If we hit a newline in the _file_ stream, we want to test and
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* see if any characters have been hit in the _input_ stream. This
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* allows the user to quit while in the middle of a file.
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*/
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wrap = (++len > terminal_width);
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if (c == '\n' || wrap) {
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/* Then outputting this character
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* will move us to a new line. */
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if (++lines >= terminal_height || input == '\n')
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please_display_more_prompt = 1;
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len = 0;
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}
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if (c != '\n' && wrap) {
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/* Then outputting this will also put a character on
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* the beginning of that new line. Thus we first want to
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* display the prompt (if any), so we skip the putchar()
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* and go back to the top of the loop, without reading
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* a new character. */
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goto loop_top;
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}
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/* My small mind cannot fathom backspaces and UTF-8 */
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putchar(c);
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die_if_ferror_stdout(); /* if tty was destroyed (closed xterm, etc) */
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}
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fclose(file);
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fflush_all();
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} while (*argv && *++argv);
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end:
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setTermSettings(cin_fileno, &initial_settings);
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return 0;
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}
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