1 /* vi: set sw=4 ts=4: */
3 * Mini less implementation for busybox
5 * Copyright (C) 2005 by Rob Sullivan <cogito.ergo.cogito@gmail.com>
7 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
12 * - Add more regular expression support - search modifiers, certain matches, etc.
13 * - Add more complex bracket searching - currently, nested brackets are
15 * - Add support for "F" as an input. This causes less to act in
16 * a similar way to tail -f.
17 * - Allow horizontal scrolling.
20 * - the inp file pointer is used so that keyboard input works after
21 * redirected input has been read from stdin
24 #include <sched.h> /* sched_yield() */
27 #if ENABLE_FEATURE_LESS_REGEXP
31 /* The escape codes for highlighted and normal text */
32 #define HIGHLIGHT "\033[7m"
33 #define NORMAL "\033[0m"
34 /* The escape code to clear the screen */
35 #define CLEAR "\033[H\033[J"
36 /* The escape code to clear to end of line */
37 #define CLEAR_2_EOL "\033[K"
40 /* Absolute max of lines eaten */
41 MAXLINES = CONFIG_FEATURE_LESS_MAXLINES,
42 /* This many "after the end" lines we will show (at max) */
46 /* Command line options */
54 FLAG_S = (1 << 6) * ENABLE_FEATURE_LESS_DASHCMD,
55 /* hijack command line options variable for internal state vars */
56 LESS_STATE_MATCH_BACKWARDS = 1 << 15,
59 #if !ENABLE_FEATURE_LESS_REGEXP
60 enum { pattern_valid = 0 };
64 int cur_fline; /* signed */
65 int kbd_fd; /* fd to get input from */
67 /* last position in last line, taking into account tabs */
70 unsigned max_lineno; /* this one tracks linewrap */
71 unsigned max_displayed_line;
73 #if ENABLE_FEATURE_LESS_WINCH
74 unsigned winch_counter;
76 ssize_t eof_error; /* eof if 0, error if < 0 */
78 ssize_t readeof; /* must be signed */
81 const char *empty_line_marker;
83 unsigned current_file;
86 #if ENABLE_FEATURE_LESS_MARKS
88 unsigned mark_lines[15][2];
90 #if ENABLE_FEATURE_LESS_REGEXP
91 unsigned *match_lines;
92 int match_pos; /* signed! */
93 int wanted_match; /* signed! */
96 smallint pattern_valid;
99 struct termios term_orig, term_less;
100 char kbd_input[KEYCODE_BUFFER_SIZE];
102 #define G (*ptr_to_globals)
103 #define cur_fline (G.cur_fline )
104 #define kbd_fd (G.kbd_fd )
105 #define less_gets_pos (G.less_gets_pos )
106 #define last_line_pos (G.last_line_pos )
107 #define max_fline (G.max_fline )
108 #define max_lineno (G.max_lineno )
109 #define max_displayed_line (G.max_displayed_line)
110 #define width (G.width )
111 #define winch_counter (G.winch_counter )
112 /* This one is 100% not cached by compiler on read access */
113 #define WINCH_COUNTER (*(volatile unsigned *)&winch_counter)
114 #define eof_error (G.eof_error )
115 #define readpos (G.readpos )
116 #define readeof (G.readeof )
117 #define buffer (G.buffer )
118 #define flines (G.flines )
119 #define empty_line_marker (G.empty_line_marker )
120 #define num_files (G.num_files )
121 #define current_file (G.current_file )
122 #define filename (G.filename )
123 #define files (G.files )
124 #define num_marks (G.num_marks )
125 #define mark_lines (G.mark_lines )
126 #if ENABLE_FEATURE_LESS_REGEXP
127 #define match_lines (G.match_lines )
128 #define match_pos (G.match_pos )
129 #define num_matches (G.num_matches )
130 #define wanted_match (G.wanted_match )
131 #define pattern (G.pattern )
132 #define pattern_valid (G.pattern_valid )
134 #define terminated (G.terminated )
135 #define term_orig (G.term_orig )
136 #define term_less (G.term_less )
137 #define kbd_input (G.kbd_input )
138 #define INIT_G() do { \
139 SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
140 less_gets_pos = -1; \
141 empty_line_marker = "~"; \
146 IF_FEATURE_LESS_REGEXP(wanted_match = -1;) \
149 /* flines[] are lines read from stdin, each in malloc'ed buffer.
150 * Line numbers are stored as uint32_t prepended to each line.
151 * Pointer is adjusted so that flines[i] points directly past
152 * line number. Accesor: */
153 #define MEMPTR(p) ((char*)(p) - 4)
154 #define LINENO(p) (*(uint32_t*)((p) - 4))
157 /* Reset terminal input to normal */
158 static void set_tty_cooked(void)
161 tcsetattr(kbd_fd, TCSANOW, &term_orig);
164 /* Move the cursor to a position (x,y), where (0,0) is the
165 top-left corner of the console */
166 static void move_cursor(int line, int row)
168 printf("\033[%u;%uH", line, row);
171 static void clear_line(void)
173 printf("\033[%u;0H" CLEAR_2_EOL, max_displayed_line + 2);
176 static void print_hilite(const char *str)
178 printf(HIGHLIGHT"%s"NORMAL, str);
181 static void print_statusline(const char *str)
184 printf(HIGHLIGHT"%.*s"NORMAL, width - 1, str);
187 /* Exit the program gracefully */
188 static void less_exit(int code)
193 kill_myself_with_sig(- code); /* does not return */
197 #if (ENABLE_FEATURE_LESS_DASHCMD && ENABLE_FEATURE_LESS_LINENUMS) \
198 || ENABLE_FEATURE_LESS_WINCH
199 static void re_wrap(void)
205 int new_cur_fline = 0;
208 const char **old_flines = flines;
210 char **new_flines = NULL;
213 if (option_mask32 & FLAG_N)
226 if (*d == '\t') /* tab */
230 if (new_line_pos >= w) {
232 /* new line is full, create next one */
235 sz = (d - linebuf) + 1; /* + 1: NUL */
236 d = ((char*)xmalloc(sz + 4)) + 4;
238 memcpy(d, linebuf, sz);
239 new_flines = xrealloc_vector(new_flines, 8, dst_idx);
240 new_flines[dst_idx] = d;
242 if (new_line_pos < w) {
243 /* if we came here thru "goto next_new" */
244 if (src_idx > max_fline)
253 /* *d == NUL: old line ended, go to next old one */
254 free(MEMPTR(old_flines[src_idx]));
255 /* btw, convert cur_fline... */
256 if (cur_fline == src_idx)
257 new_cur_fline = dst_idx;
259 /* no more lines? finish last new line (and exit the loop) */
260 if (src_idx > max_fline)
262 s = old_flines[src_idx];
263 if (lineno != LINENO(s)) {
264 /* this is not a continuation line!
265 * create next _new_ line too */
271 flines = (const char **)new_flines;
273 max_fline = dst_idx - 1;
274 last_line_pos = new_line_pos;
275 cur_fline = new_cur_fline;
276 /* max_lineno is screen-size independent */
277 #if ENABLE_FEATURE_LESS_REGEXP
283 #if ENABLE_FEATURE_LESS_REGEXP
284 static void fill_match_lines(unsigned pos);
286 #define fill_match_lines(pos) ((void)0)
289 /* Devilishly complex routine.
291 * Has to deal with EOF and EPIPE on input,
292 * with line wrapping, with last line not ending in '\n'
293 * (possibly not ending YET!), with backspace and tabs.
294 * It reads input again if last time we got an EOF (thus supporting
295 * growing files) or EPIPE (watching output of slow process like make).
298 * flines[] - array of lines already read. Linewrap may cause
299 * one source file line to occupy several flines[n].
300 * flines[max_fline] - last line, possibly incomplete.
301 * terminated - 1 if flines[max_fline] is 'terminated'
302 * (if there was '\n' [which isn't stored itself, we just remember
304 * max_lineno - last line's number, this one doesn't increment
305 * on line wrap, only on "real" new lines.
306 * readbuf[0..readeof-1] - small preliminary buffer.
307 * readbuf[readpos] - next character to add to current line.
308 * last_line_pos - screen line position of next char to be read
309 * (takes into account tabs and backspaces)
310 * eof_error - < 0 error, == 0 EOF, > 0 not EOF/error
312 static void read_lines(void)
314 #define readbuf bb_common_bufsiz1
315 char *current_line, *p;
317 char last_terminated = terminated;
318 #if ENABLE_FEATURE_LESS_REGEXP
319 unsigned old_max_fline = max_fline;
320 time_t last_time = 0;
321 unsigned seconds_p1 = 3; /* seconds_to_loop + 1 */
324 if (option_mask32 & FLAG_N)
327 IF_FEATURE_LESS_REGEXP(again0:)
329 p = current_line = ((char*)xmalloc(w + 4)) + 4;
330 max_fline += last_terminated;
331 if (!last_terminated) {
332 const char *cp = flines[max_fline];
334 p += strlen(current_line);
335 free(MEMPTR(flines[max_fline]));
336 /* last_line_pos is still valid from previous read_lines() */
341 while (1) { /* read lines until we reach cur_fline or wanted_match */
344 while (1) { /* read chars until we have a line */
346 /* if no unprocessed chars left, eat more */
347 if (readpos >= readeof) {
349 eof_error = safe_read(STDIN_FILENO, readbuf, sizeof(readbuf));
356 c = readbuf[readpos];
357 /* backspace? [needed for manpages] */
358 /* <tab><bs> is (a) insane and */
359 /* (b) harder to do correctly, so we refuse to do it */
360 if (c == '\x8' && last_line_pos && p[-1] != '\t') {
361 readpos++; /* eat it */
363 /* was buggy (p could end up <= current_line)... */
368 size_t new_last_line_pos = last_line_pos + 1;
370 new_last_line_pos += 7;
371 new_last_line_pos &= (~7);
373 if ((int)new_last_line_pos >= w)
375 last_line_pos = new_last_line_pos;
377 /* ok, we will eat this char */
384 /* NUL is substituted by '\n'! */
385 if (c == '\0') c = '\n';
388 } /* end of "read chars until we have a line" loop */
389 /* Corner case: linewrap with only "" wrapping to next line */
390 /* Looks ugly on screen, so we do not store this empty line */
391 if (!last_terminated && !current_line[0]) {
397 last_terminated = terminated;
398 flines = xrealloc_vector(flines, 8, max_fline);
400 flines[max_fline] = (char*)xrealloc(MEMPTR(current_line), strlen(current_line) + 1 + 4) + 4;
401 LINENO(flines[max_fline]) = max_lineno;
405 if (max_fline >= MAXLINES) {
406 eof_error = 0; /* Pretend we saw EOF */
409 if (!(option_mask32 & FLAG_S)
410 ? (max_fline > cur_fline + max_displayed_line)
411 : (max_fline >= cur_fline
412 && max_lineno > LINENO(flines[cur_fline]) + max_displayed_line)
414 #if !ENABLE_FEATURE_LESS_REGEXP
417 if (wanted_match >= num_matches) { /* goto_match called us */
418 fill_match_lines(old_max_fline);
419 old_max_fline = max_fline;
421 if (wanted_match < num_matches)
425 if (eof_error <= 0) {
427 if (errno == EAGAIN) {
428 /* not yet eof or error, reset flag (or else
429 * we will hog CPU - select() will return
433 print_statusline("read error");
436 #if !ENABLE_FEATURE_LESS_REGEXP
439 if (wanted_match < num_matches) {
441 } else { /* goto_match called us */
442 time_t t = time(NULL);
443 if (t != last_time) {
445 if (--seconds_p1 == 0)
449 goto again0; /* go loop again (max 2 seconds) */
454 current_line = ((char*)xmalloc(w + 4)) + 4;
457 } /* end of "read lines until we reach cur_fline" loop */
458 fill_match_lines(old_max_fline);
459 #if ENABLE_FEATURE_LESS_REGEXP
460 /* prevent us from being stuck in search for a match */
466 #if ENABLE_FEATURE_LESS_FLAGS
467 /* Interestingly, writing calc_percent as a function saves around 32 bytes
469 static int calc_percent(void)
471 unsigned p = (100 * (cur_fline+max_displayed_line+1) + max_fline/2) / (max_fline+1);
472 return p <= 100 ? p : 100;
475 /* Print a status line if -M was specified */
476 static void m_status_print(void)
480 if (less_gets_pos >= 0) /* don't touch statusline while input is done! */
484 printf(HIGHLIGHT"%s", filename);
486 printf(" (file %i of %i)", current_file, num_files);
487 printf(" lines %i-%i/%i ",
488 cur_fline + 1, cur_fline + max_displayed_line + 1,
490 if (cur_fline >= (int)(max_fline - max_displayed_line)) {
491 printf("(END)"NORMAL);
492 if (num_files > 1 && current_file != num_files)
493 printf(HIGHLIGHT" - next: %s"NORMAL, files[current_file]);
496 percentage = calc_percent();
497 printf("%i%%"NORMAL, percentage);
501 /* Print the status line */
502 static void status_print(void)
506 if (less_gets_pos >= 0) /* don't touch statusline while input is done! */
509 /* Change the status if flags have been set */
510 #if ENABLE_FEATURE_LESS_FLAGS
511 if (option_mask32 & (FLAG_M|FLAG_m)) {
519 if (cur_fline && cur_fline < (int)(max_fline - max_displayed_line)) {
527 printf(HIGHLIGHT"%s (file %i of %i)"NORMAL,
528 p, current_file, num_files);
534 static void cap_cur_fline(int nlines)
539 if (cur_fline + max_displayed_line > max_fline + TILDES) {
543 diff = max_fline - (cur_fline + max_displayed_line) + TILDES;
544 /* As the number of lines requested was too large, we just move
545 * to the end of the file */
551 static const char controls[] ALIGN1 =
552 /* NUL: never encountered; TAB: not converted */
553 /**/"\x01\x02\x03\x04\x05\x06\x07\x08" "\x0a\x0b\x0c\x0d\x0e\x0f"
554 "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
555 "\x7f\x9b"; /* DEL and infamous Meta-ESC :( */
556 static const char ctrlconv[] ALIGN1 =
557 /* why 40 instead of 4a below? - it is a replacement for '\n'.
558 * '\n' is a former NUL - we subst it with @, not J */
559 "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x40\x4b\x4c\x4d\x4e\x4f"
560 "\x50\x51\x52\x53\x54\x55\x56\x57\x58\x59\x5a\x5b\x5c\x5d\x5e\x5f";
562 static void lineno_str(char *nbuf9, const char *line)
565 if (option_mask32 & FLAG_N) {
569 if (line == empty_line_marker) {
570 memset(nbuf9, ' ', 8);
574 /* Width of 7 preserves tab spacing in the text */
576 n = LINENO(line) + 1;
581 sprintf(nbuf9, fmt, n);
586 #if ENABLE_FEATURE_LESS_REGEXP
587 static void print_found(const char *line)
592 regmatch_t match_structs;
596 const char *str = line;
601 n = strcspn(str, controls);
608 n = strspn(str, controls);
615 /* buf[] holds quarantined version of str */
617 /* Each part of the line that matches has the HIGHLIGHT
618 and NORMAL escape sequences placed around it.
619 NB: we regex against line, but insert text
620 from quarantined copy (buf[]) */
626 while (match_status == 0) {
627 char *new = xasprintf("%s%.*s"HIGHLIGHT"%.*s"NORMAL,
628 growline ? growline : "",
629 match_structs.rm_so, str,
630 match_structs.rm_eo - match_structs.rm_so,
631 str + match_structs.rm_so);
634 str += match_structs.rm_eo;
635 line += match_structs.rm_eo;
638 /* Most of the time doesn't find the regex, optimize for that */
639 match_status = regexec(&pattern, line, 1, &match_structs, eflags);
640 /* if even "" matches, treat it as "not a match" */
641 if (match_structs.rm_so >= match_structs.rm_eo)
645 lineno_str(nbuf9, line);
647 printf(CLEAR_2_EOL"%s%s\n", nbuf9, str);
650 printf(CLEAR_2_EOL"%s%s%s\n", nbuf9, growline, str);
654 void print_found(const char *line);
657 static void print_ascii(const char *str)
664 lineno_str(nbuf9, str);
665 printf(CLEAR_2_EOL"%s", nbuf9);
668 n = strcspn(str, controls);
671 printf("%.*s", (int) n, str);
674 n = strspn(str, controls);
679 else if (*str == (char)0x9b)
680 /* VT100's CSI, aka Meta-ESC. Who's inventor? */
681 /* I want to know who committed this sin */
684 *p++ = ctrlconv[(unsigned char)*str];
693 /* Print the buffer */
694 static void buffer_print(void)
699 for (i = 0; i <= max_displayed_line; i++)
701 print_found(buffer[i]);
703 print_ascii(buffer[i]);
707 static void buffer_fill_and_print(void)
710 #if ENABLE_FEATURE_LESS_DASHCMD
711 int fpos = cur_fline;
713 if (option_mask32 & FLAG_S) {
714 /* Go back to the beginning of this line */
715 while (fpos && LINENO(flines[fpos]) == LINENO(flines[fpos-1]))
720 while (i <= max_displayed_line && fpos <= max_fline) {
721 int lineno = LINENO(flines[fpos]);
722 buffer[i] = flines[fpos];
726 } while ((fpos <= max_fline)
727 && (option_mask32 & FLAG_S)
728 && lineno == LINENO(flines[fpos])
732 for (i = 0; i <= max_displayed_line && cur_fline + i <= max_fline; i++) {
733 buffer[i] = flines[cur_fline + i];
736 for (; i <= max_displayed_line; i++) {
737 buffer[i] = empty_line_marker;
742 /* Move the buffer up and down in the file in order to scroll */
743 static void buffer_down(int nlines)
747 cap_cur_fline(nlines);
748 buffer_fill_and_print();
751 static void buffer_up(int nlines)
754 if (cur_fline < 0) cur_fline = 0;
756 buffer_fill_and_print();
759 static void buffer_line(int linenum)
765 if (linenum + max_displayed_line > max_fline)
766 linenum = max_fline - max_displayed_line + TILDES;
770 buffer_fill_and_print();
773 static void open_file_and_read_lines(void)
776 xmove_fd(xopen(filename, O_RDONLY), STDIN_FILENO);
778 /* "less" with no arguments in argv[] */
779 /* For status line only */
780 filename = xstrdup(bb_msg_standard_input);
789 /* Reinitialize everything for a new file - free the memory and start over */
790 static void reinitialize(void)
795 for (i = 0; i <= max_fline; i++)
796 free(MEMPTR(flines[i]));
804 open_file_and_read_lines();
805 buffer_fill_and_print();
808 static int getch_nowait(void)
811 struct pollfd pfd[2];
813 pfd[0].fd = STDIN_FILENO;
814 pfd[0].events = POLLIN;
816 pfd[1].events = POLLIN;
818 tcsetattr(kbd_fd, TCSANOW, &term_less);
819 /* NB: select/poll returns whenever read will not block. Therefore:
820 * if eof is reached, select/poll will return immediately
821 * because read will immediately return 0 bytes.
822 * Even if select/poll says that input is available, read CAN block
823 * (switch fd into O_NONBLOCK'ed mode to avoid it)
826 /* Are we interested in stdin? */
827 //TODO: reuse code for determining this
828 if (!(option_mask32 & FLAG_S)
829 ? !(max_fline > cur_fline + max_displayed_line)
830 : !(max_fline >= cur_fline
831 && max_lineno > LINENO(flines[cur_fline]) + max_displayed_line)
833 if (eof_error > 0) /* did NOT reach eof yet */
834 rd = 0; /* yes, we are interested in stdin */
836 /* Position cursor if line input is done */
837 if (less_gets_pos >= 0)
838 move_cursor(max_displayed_line + 2, less_gets_pos + 1);
841 if (kbd_input[0] == 0) { /* if nothing is buffered */
842 #if ENABLE_FEATURE_LESS_WINCH
845 /* NB: SIGWINCH interrupts poll() */
846 r = poll(pfd + rd, 2 - rd, -1);
847 if (/*r < 0 && errno == EINTR &&*/ winch_counter)
848 return '\\'; /* anything which has no defined function */
852 safe_poll(pfd + rd, 2 - rd, -1);
856 /* We have kbd_fd in O_NONBLOCK mode, read inside read_key()
857 * would not block even if there is no input available */
858 rd = read_key(kbd_fd, kbd_input, /*timeout off:*/ -2);
860 if (errno == EAGAIN) {
861 /* No keyboard input available. Since poll() did return,
862 * we should have input on stdin */
864 buffer_fill_and_print();
867 /* EOF/error (ssh session got killed etc) */
874 /* Grab a character from input without requiring the return key.
875 * May return KEYCODE_xxx values.
876 * Note that this function works best with raw input. */
877 static int less_getch(int pos)
886 /* Discard Ctrl-something chars */
887 if (i >= 0 && i < ' ' && i != 0x0d && i != 8)
892 static char* less_gets(int sz)
896 char *result = xzalloc(1);
900 less_gets_pos = sz + i;
913 if (c < ' ') /* filters out KEYCODE_xxx too (<0) */
915 if (i >= width - sz - 1)
916 continue; /* len limit */
919 result = xrealloc(result, i+1);
923 static void examine_file(void)
927 print_statusline("Examine: ");
928 new_fname = less_gets(sizeof("Examine: ") - 1);
935 if (access(new_fname, R_OK) != 0) {
936 print_statusline("Cannot read this file");
940 filename = new_fname;
941 /* files start by = argv. why we assume that argv is infinitely long??
942 files[num_files] = filename;
943 current_file = num_files + 1;
946 num_files = current_file = 1;
950 /* This function changes the file currently being paged. direction can be one of the following:
951 * -1: go back one file
952 * 0: go to the first file
953 * 1: go forward one file */
954 static void change_file(int direction)
956 if (current_file != ((direction > 0) ? num_files : 1)) {
957 current_file = direction ? current_file + direction : 1;
959 filename = xstrdup(files[current_file - 1]);
962 print_statusline(direction > 0 ? "No next file" : "No previous file");
966 static void remove_current_file(void)
973 if (current_file != 1) {
975 for (i = 3; i <= num_files; i++)
976 files[i - 2] = files[i - 1];
980 for (i = 2; i <= num_files; i++)
981 files[i - 2] = files[i - 1];
987 static void colon_process(void)
991 /* Clear the current line and print a prompt */
992 print_statusline(" :");
994 keypress = less_getch(2);
997 remove_current_file();
1002 #if ENABLE_FEATURE_LESS_FLAGS
1014 less_exit(EXIT_SUCCESS);
1022 #if ENABLE_FEATURE_LESS_REGEXP
1023 static void normalize_match_pos(int match)
1025 if (match >= num_matches)
1026 match = num_matches - 1;
1032 static void goto_match(int match)
1038 /* Try to find next match if eof isn't reached yet */
1039 if (match >= num_matches && eof_error > 0) {
1040 wanted_match = match; /* "I want to read until I see N'th match" */
1044 normalize_match_pos(match);
1045 buffer_line(match_lines[match_pos]);
1047 print_statusline("No matches found");
1051 static void fill_match_lines(unsigned pos)
1055 /* Run the regex on each line of the current file */
1056 while (pos <= max_fline) {
1057 /* If this line matches */
1058 if (regexec(&pattern, flines[pos], 0, NULL, 0) == 0
1059 /* and we didn't match it last time */
1060 && !(num_matches && match_lines[num_matches-1] == pos)
1062 match_lines = xrealloc_vector(match_lines, 4, num_matches);
1063 match_lines[num_matches++] = pos;
1069 static void regex_process(void)
1071 char *uncomp_regex, *err;
1073 /* Reset variables */
1078 if (pattern_valid) {
1083 /* Get the uncompiled regular expression from the user */
1085 bb_putchar((option_mask32 & LESS_STATE_MATCH_BACKWARDS) ? '?' : '/');
1086 uncomp_regex = less_gets(1);
1087 if (!uncomp_regex[0]) {
1093 /* Compile the regex and check for errors */
1094 err = regcomp_or_errmsg(&pattern, uncomp_regex,
1095 (option_mask32 & FLAG_I) ? REG_ICASE : 0);
1098 print_statusline(err);
1105 fill_match_lines(0);
1106 while (match_pos < num_matches) {
1107 if ((int)match_lines[match_pos] > cur_fline)
1111 if (option_mask32 & LESS_STATE_MATCH_BACKWARDS)
1114 /* It's possible that no matches are found yet.
1115 * goto_match() will read input looking for match,
1117 goto_match(match_pos);
1121 static void number_process(int first_digit)
1126 char num_input[sizeof(int)*4]; /* more than enough */
1128 num_input[0] = first_digit;
1130 /* Clear the current line, print a prompt, and then print the digit */
1132 printf(":%c", first_digit);
1134 /* Receive input until a letter is given */
1136 while (i < sizeof(num_input)-1) {
1137 keypress = less_getch(i + 1);
1138 if ((unsigned)keypress > 255 || !isdigit(num_input[i]))
1140 num_input[i] = keypress;
1141 bb_putchar(keypress);
1145 num_input[i] = '\0';
1146 num = bb_strtou(num_input, NULL, 10);
1147 /* on format error, num == -1 */
1148 if (num < 1 || num > MAXLINES) {
1153 /* We now know the number and the letter entered, so we process them */
1155 case KEYCODE_DOWN: case 'z': case 'd': case 'e': case ' ': case '\015':
1158 case KEYCODE_UP: case 'b': case 'w': case 'y': case 'u':
1161 case 'g': case '<': case 'G': case '>':
1162 cur_fline = num + max_displayed_line;
1164 buffer_line(num - 1);
1167 num = num * (max_fline / 100); /* + max_fline / 2; */
1168 cur_fline = num + max_displayed_line;
1172 #if ENABLE_FEATURE_LESS_REGEXP
1174 goto_match(match_pos + num);
1177 option_mask32 &= ~LESS_STATE_MATCH_BACKWARDS;
1181 option_mask32 |= LESS_STATE_MATCH_BACKWARDS;
1188 #if ENABLE_FEATURE_LESS_DASHCMD
1189 static void flag_change(void)
1195 keypress = less_getch(1);
1199 option_mask32 ^= FLAG_M;
1202 option_mask32 ^= FLAG_m;
1205 option_mask32 ^= FLAG_E;
1208 option_mask32 ^= FLAG_TILDE;
1211 option_mask32 ^= FLAG_S;
1212 buffer_fill_and_print();
1214 #if ENABLE_FEATURE_LESS_LINENUMS
1216 option_mask32 ^= FLAG_N;
1218 buffer_fill_and_print();
1225 static void show_flag_status(void)
1232 keypress = less_getch(1);
1236 flag_val = option_mask32 & FLAG_M;
1239 flag_val = option_mask32 & FLAG_m;
1242 flag_val = option_mask32 & FLAG_TILDE;
1245 flag_val = option_mask32 & FLAG_N;
1248 flag_val = option_mask32 & FLAG_E;
1256 printf(HIGHLIGHT"The status of the flag is: %u"NORMAL, flag_val != 0);
1260 #endif /* ENABLE_FEATURE_LESS_DASHCMD */
1262 static void save_input_to_file(void)
1264 const char *msg = "";
1269 print_statusline("Log file: ");
1270 current_line = less_gets(sizeof("Log file: ")-1);
1271 if (current_line[0]) {
1272 fp = fopen_for_write(current_line);
1274 msg = "Error opening log file";
1277 for (i = 0; i <= max_fline; i++)
1278 fprintf(fp, "%s\n", flines[i]);
1283 print_statusline(msg);
1287 #if ENABLE_FEATURE_LESS_MARKS
1288 static void add_mark(void)
1292 print_statusline("Mark: ");
1293 letter = less_getch(sizeof("Mark: ") - 1);
1295 if (isalpha(letter)) {
1296 /* If we exceed 15 marks, start overwriting previous ones */
1297 if (num_marks == 14)
1300 mark_lines[num_marks][0] = letter;
1301 mark_lines[num_marks][1] = cur_fline;
1304 print_statusline("Invalid mark letter");
1308 static void goto_mark(void)
1313 print_statusline("Go to mark: ");
1314 letter = less_getch(sizeof("Go to mark: ") - 1);
1317 if (isalpha(letter)) {
1318 for (i = 0; i <= num_marks; i++)
1319 if (letter == mark_lines[i][0]) {
1320 buffer_line(mark_lines[i][1]);
1323 if (num_marks == 14 && letter != mark_lines[14][0])
1324 print_statusline("Mark not set");
1326 print_statusline("Invalid mark letter");
1330 #if ENABLE_FEATURE_LESS_BRACKETS
1331 static char opp_bracket(char bracket)
1334 case '{': case '[': /* '}' == '{' + 2. Same for '[' */
1336 case '(': /* ')' == '(' + 1 */
1348 static void match_right_bracket(char bracket)
1352 if (strchr(flines[cur_fline], bracket) == NULL) {
1353 print_statusline("No bracket in top line");
1356 bracket = opp_bracket(bracket);
1357 for (i = cur_fline + 1; i < max_fline; i++) {
1358 if (strchr(flines[i], bracket) != NULL) {
1363 print_statusline("No matching bracket found");
1366 static void match_left_bracket(char bracket)
1370 if (strchr(flines[cur_fline + max_displayed_line], bracket) == NULL) {
1371 print_statusline("No bracket in bottom line");
1375 bracket = opp_bracket(bracket);
1376 for (i = cur_fline + max_displayed_line; i >= 0; i--) {
1377 if (strchr(flines[i], bracket) != NULL) {
1382 print_statusline("No matching bracket found");
1384 #endif /* FEATURE_LESS_BRACKETS */
1386 static void keypress_process(int keypress)
1389 case KEYCODE_DOWN: case 'e': case 'j': case 0x0d:
1392 case KEYCODE_UP: case 'y': case 'k':
1395 case KEYCODE_PAGEDOWN: case ' ': case 'z': case 'f':
1396 buffer_down(max_displayed_line + 1);
1398 case KEYCODE_PAGEUP: case 'w': case 'b':
1399 buffer_up(max_displayed_line + 1);
1402 buffer_down((max_displayed_line + 1) / 2);
1405 buffer_up((max_displayed_line + 1) / 2);
1407 case KEYCODE_HOME: case 'g': case 'p': case '<': case '%':
1410 case KEYCODE_END: case 'G': case '>':
1411 cur_fline = MAXLINES;
1413 buffer_line(cur_fline);
1416 less_exit(EXIT_SUCCESS);
1418 #if ENABLE_FEATURE_LESS_MARKS
1435 save_input_to_file();
1440 #if ENABLE_FEATURE_LESS_FLAGS
1445 #if ENABLE_FEATURE_LESS_REGEXP
1447 option_mask32 &= ~LESS_STATE_MATCH_BACKWARDS;
1451 goto_match(match_pos + 1);
1454 goto_match(match_pos - 1);
1457 option_mask32 |= LESS_STATE_MATCH_BACKWARDS;
1461 #if ENABLE_FEATURE_LESS_DASHCMD
1472 #if ENABLE_FEATURE_LESS_BRACKETS
1473 case '{': case '(': case '[':
1474 match_right_bracket(keypress);
1476 case '}': case ')': case ']':
1477 match_left_bracket(keypress);
1485 if (isdigit(keypress))
1486 number_process(keypress);
1489 static void sig_catcher(int sig)
1494 #if ENABLE_FEATURE_LESS_WINCH
1495 static void sigwinch_handler(int sig UNUSED_PARAM)
1501 int less_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1502 int less_main(int argc, char **argv)
1508 /* TODO: -x: do not interpret backspace, -xx: tab also */
1509 /* -xxx: newline also */
1510 /* -w N: assume width N (-xxx -w 32: hex viewer of sorts) */
1511 getopt32(argv, "EMmN~I" IF_FEATURE_LESS_DASHCMD("S"));
1517 /* Another popular pager, most, detects when stdout
1518 * is not a tty and turns into cat. This makes sense. */
1519 if (!isatty(STDOUT_FILENO))
1520 return bb_cat(argv);
1523 if (isatty(STDIN_FILENO)) {
1524 /* Just "less"? No args and no redirection? */
1525 bb_error_msg("missing filename");
1529 filename = xstrdup(files[0]);
1532 if (option_mask32 & FLAG_TILDE)
1533 empty_line_marker = "";
1535 kbd_fd = open(CURRENT_TTY, O_RDONLY);
1537 return bb_cat(argv);
1540 tcgetattr(kbd_fd, &term_orig);
1541 term_less = term_orig;
1542 term_less.c_lflag &= ~(ICANON | ECHO);
1543 term_less.c_iflag &= ~(IXON | ICRNL);
1544 /*term_less.c_oflag &= ~ONLCR;*/
1545 term_less.c_cc[VMIN] = 1;
1546 term_less.c_cc[VTIME] = 0;
1548 get_terminal_width_height(kbd_fd, &width, &max_displayed_line);
1549 /* 20: two tabstops + 4 */
1550 if (width < 20 || max_displayed_line < 3)
1551 return bb_cat(argv);
1552 max_displayed_line -= 2;
1554 /* We want to restore term_orig on exit */
1555 bb_signals(BB_FATAL_SIGS, sig_catcher);
1556 #if ENABLE_FEATURE_LESS_WINCH
1557 signal(SIGWINCH, sigwinch_handler);
1560 buffer = xmalloc((max_displayed_line+1) * sizeof(char *));
1563 #if ENABLE_FEATURE_LESS_WINCH
1564 while (WINCH_COUNTER) {
1567 get_terminal_width_height(kbd_fd, &width, &max_displayed_line);
1568 /* 20: two tabstops + 4 */
1571 if (max_displayed_line < 3)
1572 max_displayed_line = 3;
1573 max_displayed_line -= 2;
1575 buffer = xmalloc((max_displayed_line+1) * sizeof(char *));
1576 /* Avoid re-wrap and/or redraw if we already know
1577 * we need to do it again. These ops are expensive */
1583 buffer_fill_and_print();
1584 /* This took some time. Loop back and check,
1585 * were there another SIGWINCH? */
1588 keypress = less_getch(-1); /* -1: do not position cursor */
1589 keypress_process(keypress);
1594 Help text of less version 418 is below.
1595 If you are implementing something, keeping
1596 key and/or command line switch compatibility is a good idea:
1599 SUMMARY OF LESS COMMANDS
1601 Commands marked with * may be preceded by a number, N.
1602 Notes in parentheses indicate the behavior if N is given.
1603 h H Display this help.
1605 ---------------------------------------------------------------------------
1607 e ^E j ^N CR * Forward one line (or N lines).
1608 y ^Y k ^K ^P * Backward one line (or N lines).
1609 f ^F ^V SPACE * Forward one window (or N lines).
1610 b ^B ESC-v * Backward one window (or N lines).
1611 z * Forward one window (and set window to N).
1612 w * Backward one window (and set window to N).
1613 ESC-SPACE * Forward one window, but don't stop at end-of-file.
1614 d ^D * Forward one half-window (and set half-window to N).
1615 u ^U * Backward one half-window (and set half-window to N).
1616 ESC-) RightArrow * Left one half screen width (or N positions).
1617 ESC-( LeftArrow * Right one half screen width (or N positions).
1618 F Forward forever; like "tail -f".
1619 r ^R ^L Repaint screen.
1620 R Repaint screen, discarding buffered input.
1621 ---------------------------------------------------
1622 Default "window" is the screen height.
1623 Default "half-window" is half of the screen height.
1624 ---------------------------------------------------------------------------
1626 /pattern * Search forward for (N-th) matching line.
1627 ?pattern * Search backward for (N-th) matching line.
1628 n * Repeat previous search (for N-th occurrence).
1629 N * Repeat previous search in reverse direction.
1630 ESC-n * Repeat previous search, spanning files.
1631 ESC-N * Repeat previous search, reverse dir. & spanning files.
1632 ESC-u Undo (toggle) search highlighting.
1633 ---------------------------------------------------
1634 Search patterns may be modified by one or more of:
1635 ^N or ! Search for NON-matching lines.
1636 ^E or * Search multiple files (pass thru END OF FILE).
1637 ^F or @ Start search at FIRST file (for /) or last file (for ?).
1638 ^K Highlight matches, but don't move (KEEP position).
1639 ^R Don't use REGULAR EXPRESSIONS.
1640 ---------------------------------------------------------------------------
1642 g < ESC-< * Go to first line in file (or line N).
1643 G > ESC-> * Go to last line in file (or line N).
1644 p % * Go to beginning of file (or N percent into file).
1645 t * Go to the (N-th) next tag.
1646 T * Go to the (N-th) previous tag.
1647 { ( [ * Find close bracket } ) ].
1648 } ) ] * Find open bracket { ( [.
1649 ESC-^F <c1> <c2> * Find close bracket <c2>.
1650 ESC-^B <c1> <c2> * Find open bracket <c1>
1651 ---------------------------------------------------
1652 Each "find close bracket" command goes forward to the close bracket
1653 matching the (N-th) open bracket in the top line.
1654 Each "find open bracket" command goes backward to the open bracket
1655 matching the (N-th) close bracket in the bottom line.
1656 m<letter> Mark the current position with <letter>.
1657 '<letter> Go to a previously marked position.
1658 '' Go to the previous position.
1660 ---------------------------------------------------
1661 A mark is any upper-case or lower-case letter.
1662 Certain marks are predefined:
1663 ^ means beginning of the file
1664 $ means end of the file
1665 ---------------------------------------------------------------------------
1667 :e [file] Examine a new file.
1669 :n * Examine the (N-th) next file from the command line.
1670 :p * Examine the (N-th) previous file from the command line.
1671 :x * Examine the first (or N-th) file from the command line.
1672 :d Delete the current file from the command line list.
1673 = ^G :f Print current file name.
1674 ---------------------------------------------------------------------------
1675 MISCELLANEOUS COMMANDS
1676 -<flag> Toggle a command line option [see OPTIONS below].
1677 --<name> Toggle a command line option, by name.
1678 _<flag> Display the setting of a command line option.
1679 __<name> Display the setting of an option, by name.
1680 +cmd Execute the less cmd each time a new file is examined.
1681 !command Execute the shell command with $SHELL.
1682 |Xcommand Pipe file between current pos & mark X to shell command.
1683 v Edit the current file with $VISUAL or $EDITOR.
1684 V Print version number of "less".
1685 ---------------------------------------------------------------------------
1687 Most options may be changed either on the command line,
1688 or from within less by using the - or -- command.
1689 Options may be given in one of two forms: either a single
1690 character preceded by a -, or a name preceeded by --.
1692 Display help (from command line).
1693 -a ........ --search-skip-screen
1694 Forward search skips current screen.
1695 -b [N] .... --buffers=[N]
1697 -B ........ --auto-buffers
1698 Don't automatically allocate buffers for pipes.
1699 -c ........ --clear-screen
1700 Repaint by clearing rather than scrolling.
1703 -D [xn.n] . --color=xn.n
1704 Set screen colors. (MS-DOS only)
1705 -e -E .... --quit-at-eof --QUIT-AT-EOF
1706 Quit at end of file.
1708 Force open non-regular files.
1709 -F ........ --quit-if-one-screen
1710 Quit if entire file fits on first screen.
1711 -g ........ --hilite-search
1712 Highlight only last match for searches.
1713 -G ........ --HILITE-SEARCH
1714 Don't highlight any matches for searches.
1715 -h [N] .... --max-back-scroll=[N]
1716 Backward scroll limit.
1717 -i ........ --ignore-case
1718 Ignore case in searches that do not contain uppercase.
1719 -I ........ --IGNORE-CASE
1720 Ignore case in all searches.
1721 -j [N] .... --jump-target=[N]
1722 Screen position of target lines.
1723 -J ........ --status-column
1724 Display a status column at left edge of screen.
1725 -k [file] . --lesskey-file=[file]
1727 -L ........ --no-lessopen
1728 Ignore the LESSOPEN environment variable.
1729 -m -M .... --long-prompt --LONG-PROMPT
1731 -n -N .... --line-numbers --LINE-NUMBERS
1732 Don't use line numbers.
1733 -o [file] . --log-file=[file]
1734 Copy to log file (standard input only).
1735 -O [file] . --LOG-FILE=[file]
1736 Copy to log file (unconditionally overwrite).
1737 -p [pattern] --pattern=[pattern]
1738 Start at pattern (from command line).
1739 -P [prompt] --prompt=[prompt]
1741 -q -Q .... --quiet --QUIET --silent --SILENT
1742 Quiet the terminal bell.
1743 -r -R .... --raw-control-chars --RAW-CONTROL-CHARS
1744 Output "raw" control characters.
1745 -s ........ --squeeze-blank-lines
1746 Squeeze multiple blank lines.
1747 -S ........ --chop-long-lines
1749 -t [tag] .. --tag=[tag]
1751 -T [tagsfile] --tag-file=[tagsfile]
1752 Use an alternate tags file.
1753 -u -U .... --underline-special --UNDERLINE-SPECIAL
1754 Change handling of backspaces.
1755 -V ........ --version
1756 Display the version number of "less".
1757 -w ........ --hilite-unread
1758 Highlight first new line after forward-screen.
1759 -W ........ --HILITE-UNREAD
1760 Highlight first new line after any forward movement.
1761 -x [N[,...]] --tabs=[N[,...]]
1763 -X ........ --no-init
1764 Don't use termcap init/deinit strings.
1766 Don't use termcap keypad init/deinit strings.
1767 -y [N] .... --max-forw-scroll=[N]
1768 Forward scroll limit.
1769 -z [N] .... --window=[N]
1771 -" [c[c]] . --quotes=[c[c]]
1772 Set shell quote characters.
1774 Don't display tildes after end of file.
1775 -# [N] .... --shift=[N]
1776 Horizontal scroll amount (0 = one half screen width)
1778 ---------------------------------------------------------------------------
1780 These keys can be used to edit text being entered
1781 on the "command line" at the bottom of the screen.
1782 RightArrow ESC-l Move cursor right one character.
1783 LeftArrow ESC-h Move cursor left one character.
1784 CNTL-RightArrow ESC-RightArrow ESC-w Move cursor right one word.
1785 CNTL-LeftArrow ESC-LeftArrow ESC-b Move cursor left one word.
1786 HOME ESC-0 Move cursor to start of line.
1787 END ESC-$ Move cursor to end of line.
1788 BACKSPACE Delete char to left of cursor.
1789 DELETE ESC-x Delete char under cursor.
1790 CNTL-BACKSPACE ESC-BACKSPACE Delete word to left of cursor.
1791 CNTL-DELETE ESC-DELETE ESC-X Delete word under cursor.
1792 CNTL-U ESC (MS-DOS only) Delete entire line.
1793 UpArrow ESC-k Retrieve previous command line.
1794 DownArrow ESC-j Retrieve next command line.
1795 TAB Complete filename & cycle.
1796 SHIFT-TAB ESC-TAB Complete filename & reverse cycle.
1797 CNTL-L Complete filename, list all.