diff options
Diffstat (limited to 'util-linux/more.c')
| -rw-r--r-- | util-linux/more.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/util-linux/more.c b/util-linux/more.c new file mode 100644 index 0000000..cf8e137 --- /dev/null +++ b/util-linux/more.c @@ -0,0 +1,205 @@ +/* vi: set sw=4 ts=4: */ +/* + * Mini more implementation for busybox + * + * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>. + * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> + * + * Latest version blended together by Erik Andersen <andersen@codepoet.org>, + * based on the original more implementation by Bruce, and code from the + * Debian boot-floppies team. + * + * Termios corrects by Vladimir Oleynik <dzo@simtreas.ru> + * + * Licensed under GPLv2 or later, see file License in this tarball for details. + */ + +#include "libbb.h" +#if ENABLE_FEATURE_USE_TERMIOS +#include <termios.h> +#endif /* FEATURE_USE_TERMIOS */ + + +#if ENABLE_FEATURE_USE_TERMIOS + +struct globals { + int cin_fileno; + struct termios initial_settings; + struct termios new_settings; +}; +#define G (*(struct globals*)bb_common_bufsiz1) +#define INIT_G() ((void)0) +#define initial_settings (G.initial_settings) +#define new_settings (G.new_settings ) +#define cin_fileno (G.cin_fileno ) + +#define setTermSettings(fd, argp) tcsetattr(fd, TCSANOW, argp) +#define getTermSettings(fd, argp) tcgetattr(fd, argp) + +static void gotsig(int sig UNUSED_PARAM) +{ + bb_putchar('\n'); + setTermSettings(cin_fileno, &initial_settings); + exit(EXIT_FAILURE); +} + +#else /* !FEATURE_USE_TERMIOS */ +#define INIT_G() ((void)0) +#define setTermSettings(fd, argp) ((void)0) +#endif /* FEATURE_USE_TERMIOS */ + +#define CONVERTED_TAB_SIZE 8 + +int more_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int more_main(int argc UNUSED_PARAM, char **argv) +{ + int c = c; /* for gcc */ + int lines; + int input = 0; + int spaces = 0; + int please_display_more_prompt; + struct stat st; + FILE *file; + FILE *cin; + int len; + unsigned terminal_width; + unsigned terminal_height; + + INIT_G(); + + 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_for_read(CURRENT_TTY); + if (!cin) + return bb_cat(argv); + +#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); + bb_signals(0 + + (1 << SIGINT) + + (1 << SIGQUIT) + + (1 << SIGTERM) + , gotsig); +#endif + + do { + file = stdin; + if (*argv) { + file = fopen_or_warn(*argv, "r"); + if (!file) + continue; + } + st.st_size = 0; + fstat(fileno(file), &st); + + please_display_more_prompt = 0; + /* never returns w, h <= 1 */ + get_terminal_width_height(fileno(cin), &terminal_width, &terminal_height); + terminal_height -= 1; + + len = 0; + lines = 0; + while (spaces || (c = getc(file)) != EOF) { + int wrap; + if (spaces) + spaces--; + loop_top: + if (input != 'r' && please_display_more_prompt) { + len = printf("--More-- "); + if (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. + */ + for (;;) { + input = getc(cin); + input = tolower(input); +#if !ENABLE_FEATURE_USE_TERMIOS + printf("\033[A"); /* up cursor */ +#endif + /* Erase the last message */ + printf("\r%*s\r", len, ""); + + /* Due to various multibyte escape + * sequences, it's not ok to accept + * any input as a command to scroll + * the screen. We only allow known + * commands, else we show help msg. */ + if (input == ' ' || input == '\n' || input == 'q' || input == 'r') + break; + len = printf("(Enter:next line Space:next page Q:quit R:show the rest)"); + } + len = 0; + lines = 0; + please_display_more_prompt = 0; + + if (input == 'q') + goto end; + + /* The user may have resized the terminal. + * Re-read the dimensions. */ +#if ENABLE_FEATURE_USE_TERMIOS + get_terminal_width_height(cin_fileno, &terminal_width, &terminal_height); + terminal_height -= 1; +#endif + } + + /* Crudely convert tabs into spaces, which are + * a bajillion times easier to deal with. */ + if (c == '\t') { + spaces = CONVERTED_TAB_SIZE - 1; + c = ' '; + } + + /* + * 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. + */ + wrap = (++len > terminal_width); + if (c == '\n' || wrap) { + /* Then outputting this character + * will move us to a new line. */ + if (++lines >= terminal_height || input == '\n') + please_display_more_prompt = 1; + len = 0; + } + if (c != '\n' && wrap) { + /* Then outputting this will also put a character on + * the beginning of that new line. Thus we first want to + * display the prompt (if any), so we skip the putchar() + * and go back to the top of the loop, without reading + * a new character. */ + goto loop_top; + } + /* My small mind cannot fathom backspaces and UTF-8 */ + putchar(c); + } + fclose(file); + fflush(stdout); + } while (*argv && *++argv); + end: + setTermSettings(cin_fileno, &initial_settings); + return 0; +} |