busybox/miscutils/less.c

1377 lines
31 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Mini less implementation for busybox
*
* Copyright (C) 2005 by Rob Sullivan <cogito.ergo.cogito@gmail.com>
*
* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/
/*
* TODO:
* - Add more regular expression support - search modifiers, certain matches, etc.
* - Add more complex bracket searching - currently, nested brackets are
* not considered.
* - Add support for "F" as an input. This causes less to act in
* a similar way to tail -f.
* - Allow horizontal scrolling.
*
* Notes:
* - the inp file pointer is used so that keyboard input works after
* redirected input has been read from stdin
*/
#include <sched.h> /* sched_yield() */
#include "libbb.h"
#if ENABLE_FEATURE_LESS_REGEXP
#include "xregex.h"
#endif
/* FIXME: currently doesn't work right */
#undef ENABLE_FEATURE_LESS_FLAGCS
#define ENABLE_FEATURE_LESS_FLAGCS 0
/* The escape codes for highlighted and normal text */
#define HIGHLIGHT "\033[7m"
#define NORMAL "\033[0m"
/* The escape code to clear the screen */
#define CLEAR "\033[H\033[J"
/* The escape code to clear to end of line */
#define CLEAR_2_EOL "\033[K"
/* These are the escape sequences corresponding to special keys */
enum {
REAL_KEY_UP = 'A',
REAL_KEY_DOWN = 'B',
REAL_KEY_RIGHT = 'C',
REAL_KEY_LEFT = 'D',
REAL_PAGE_UP = '5',
REAL_PAGE_DOWN = '6',
REAL_KEY_HOME = '7', // vt100? linux vt? or what?
REAL_KEY_END = '8',
REAL_KEY_HOME_ALT = '1', // ESC [1~ (vt100? linux vt? or what?)
REAL_KEY_END_ALT = '4', // ESC [4~
REAL_KEY_HOME_XTERM = 'H',
REAL_KEY_END_XTERM = 'F',
/* These are the special codes assigned by this program to the special keys */
KEY_UP = 20,
KEY_DOWN = 21,
KEY_RIGHT = 22,
KEY_LEFT = 23,
PAGE_UP = 24,
PAGE_DOWN = 25,
KEY_HOME = 26,
KEY_END = 27,
/* Absolute max of lines eaten */
MAXLINES = CONFIG_FEATURE_LESS_MAXLINES,
/* This many "after the end" lines we will show (at max) */
TILDES = 1,
};
/* Command line options */
enum {
FLAG_E = 1,
FLAG_M = 1 << 1,
FLAG_m = 1 << 2,
FLAG_N = 1 << 3,
FLAG_TILDE = 1 << 4,
/* hijack command line options variable for internal state vars */
LESS_STATE_MATCH_BACKWARDS = 1 << 15,
};
#if !ENABLE_FEATURE_LESS_REGEXP
enum { pattern_valid = 0 };
#endif
struct globals {
int cur_fline; /* signed */
int kbd_fd; /* fd to get input from */
/* last position in last line, taking into account tabs */
size_t linepos;
unsigned max_displayed_line;
unsigned max_fline;
unsigned max_lineno; /* this one tracks linewrap */
unsigned width;
ssize_t eof_error; /* eof if 0, error if < 0 */
size_t readpos;
size_t readeof;
const char **buffer;
const char **flines;
const char *empty_line_marker;
unsigned num_files;
unsigned current_file;
char *filename;
char **files;
#if ENABLE_FEATURE_LESS_MARKS
unsigned num_marks;
unsigned mark_lines[15][2];
#endif
#if ENABLE_FEATURE_LESS_REGEXP
unsigned *match_lines;
int match_pos; /* signed! */
unsigned num_matches;
regex_t pattern;
smallint pattern_valid;
#endif
smallint terminated;
struct termios term_orig, term_less;
};
#define G (*ptr_to_globals)
#define cur_fline (G.cur_fline )
#define kbd_fd (G.kbd_fd )
#define linepos (G.linepos )
#define max_displayed_line (G.max_displayed_line)
#define max_fline (G.max_fline )
#define max_lineno (G.max_lineno )
#define width (G.width )
#define eof_error (G.eof_error )
#define readpos (G.readpos )
#define readeof (G.readeof )
#define buffer (G.buffer )
#define flines (G.flines )
#define empty_line_marker (G.empty_line_marker )
#define num_files (G.num_files )
#define current_file (G.current_file )
#define filename (G.filename )
#define files (G.files )
#define num_marks (G.num_marks )
#define mark_lines (G.mark_lines )
#if ENABLE_FEATURE_LESS_REGEXP
#define match_lines (G.match_lines )
#define match_pos (G.match_pos )
#define num_matches (G.num_matches )
#define pattern (G.pattern )
#define pattern_valid (G.pattern_valid )
#endif
#define terminated (G.terminated )
#define term_orig (G.term_orig )
#define term_less (G.term_less )
#define INIT_G() do { \
PTR_TO_GLOBALS = xzalloc(sizeof(G)); \
empty_line_marker = "~"; \
num_files = 1; \
current_file = 1; \
eof_error = 1; \
terminated = 1; \
} while (0)
/* Reset terminal input to normal */
static void set_tty_cooked(void)
{
fflush(stdout);
tcsetattr(kbd_fd, TCSANOW, &term_orig);
}
/* Exit the program gracefully */
static void less_exit(int code)
{
/* TODO: We really should save the terminal state when we start,
* and restore it when we exit. Less does this with the
* "ti" and "te" termcap commands; can this be done with
* only termios.h? */
bb_putchar('\n');
fflush_stdout_and_exit(code);
}
/* Move the cursor to a position (x,y), where (0,0) is the
top-left corner of the console */
static void move_cursor(int line, int row)
{
printf("\033[%u;%uH", line, row);
}
static void clear_line(void)
{
printf("\033[%u;0H" CLEAR_2_EOL, max_displayed_line + 2);
}
static void print_hilite(const char *str)
{
printf(HIGHLIGHT"%s"NORMAL, str);
}
static void print_statusline(const char *str)
{
clear_line();
printf(HIGHLIGHT"%.*s"NORMAL, width - 1, str);
}
#if ENABLE_FEATURE_LESS_REGEXP
static void fill_match_lines(unsigned pos);
#else
#define fill_match_lines(pos) ((void)0)
#endif
/* Devilishly complex routine.
*
* Has to deal with EOF and EPIPE on input,
* with line wrapping, with last line not ending in '\n'
* (possibly not ending YET!), with backspace and tabs.
* It reads input again if last time we got an EOF (thus supporting
* growing files) or EPIPE (watching output of slow process like make).
*
* Variables used:
* flines[] - array of lines already read. Linewrap may cause
* one source file line to occupy several flines[n].
* flines[max_fline] - last line, possibly incomplete.
* terminated - 1 if flines[max_fline] is 'terminated'
* (if there was '\n' [which isn't stored itself, we just remember
* that it was seen])
* max_lineno - last line's number, this one doesn't increment
* on line wrap, only on "real" new lines.
* readbuf[0..readeof-1] - small preliminary buffer.
* readbuf[readpos] - next character to add to current line.
* linepos - screen line position of next char to be read
* (takes into account tabs and backspaces)
* eof_error - < 0 error, == 0 EOF, > 0 not EOF/error
*/
static void read_lines(void)
{
#define readbuf bb_common_bufsiz1
char *current_line, *p;
USE_FEATURE_LESS_REGEXP(unsigned old_max_fline = max_fline;)
int w = width;
char last_terminated = terminated;
if (option_mask32 & FLAG_N)
w -= 8;
current_line = xmalloc(w);
p = current_line;
max_fline += last_terminated;
if (!last_terminated) {
const char *cp = flines[max_fline];
if (option_mask32 & FLAG_N)
cp += 8;
strcpy(current_line, cp);
p += strlen(current_line);
/* linepos is still valid from previous read_lines() */
} else {
linepos = 0;
}
while (1) {
again:
*p = '\0';
terminated = 0;
while (1) {
char c;
/* if no unprocessed chars left, eat more */
if (readpos >= readeof) {
smallint yielded = 0;
ndelay_on(0);
read_again:
eof_error = safe_read(0, readbuf, sizeof(readbuf));
readpos = 0;
readeof = eof_error;
if (eof_error < 0) {
if (errno == EAGAIN && !yielded) {
/* We can hit EAGAIN while searching for regexp match.
* Yield is not 100% reliable solution in general,
* but for less it should be good enough -
* we give stdin supplier some CPU time to produce
* more input. We do it just once.
* Currently, we do not stop when we found the Nth
* occurrence we were looking for. We read till end
* (or double EAGAIN). TODO? */
sched_yield();
yielded = 1;
goto read_again;
}
readeof = 0;
if (errno != EAGAIN)
print_statusline("read error");
}
ndelay_off(0);
if (eof_error <= 0) {
goto reached_eof;
}
}
c = readbuf[readpos];
/* backspace? [needed for manpages] */
/* <tab><bs> is (a) insane and */
/* (b) harder to do correctly, so we refuse to do it */
if (c == '\x8' && linepos && p[-1] != '\t') {
readpos++; /* eat it */
linepos--;
/* was buggy (p could end up <= current_line)... */
*--p = '\0';
continue;
}
{
size_t new_linepos = linepos + 1;
if (c == '\t') {
new_linepos += 7;
new_linepos &= (~7);
}
if (new_linepos >= w)
break;
linepos = new_linepos;
}
/* ok, we will eat this char */
readpos++;
if (c == '\n') {
terminated = 1;
linepos = 0;
break;
}
/* NUL is substituted by '\n'! */
if (c == '\0') c = '\n';
*p++ = c;
*p = '\0';
}
/* Corner case: linewrap with only "" wrapping to next line */
/* Looks ugly on screen, so we do not store this empty line */
if (!last_terminated && !current_line[0]) {
last_terminated = 1;
max_lineno++;
goto again;
}
reached_eof:
last_terminated = terminated;
flines = xrealloc(flines, (max_fline+1) * sizeof(char *));
if (option_mask32 & FLAG_N) {
/* Width of 7 preserves tab spacing in the text */
flines[max_fline] = xasprintf(
(max_lineno <= 9999999) ? "%7u %s" : "%07u %s",
max_lineno % 10000000, current_line);
free(current_line);
if (terminated)
max_lineno++;
} else {
flines[max_fline] = xrealloc(current_line, strlen(current_line)+1);
}
if (max_fline >= MAXLINES) {
eof_error = 0; /* Pretend we saw EOF */
break;
}
if (max_fline > cur_fline + max_displayed_line)
break;
if (eof_error <= 0) {
if (eof_error < 0 && errno == EAGAIN) {
/* not yet eof or error, reset flag (or else
* we will hog CPU - select() will return
* immediately */
eof_error = 1;
}
break;
}
max_fline++;
current_line = xmalloc(w);
p = current_line;
linepos = 0;
}
fill_match_lines(old_max_fline);
#undef readbuf
}
#if ENABLE_FEATURE_LESS_FLAGS
/* Interestingly, writing calc_percent as a function saves around 32 bytes
* on my build. */
static int calc_percent(void)
{
unsigned p = (100 * (cur_fline+max_displayed_line+1) + max_fline/2) / (max_fline+1);
return p <= 100 ? p : 100;
}
/* Print a status line if -M was specified */
static void m_status_print(void)
{
int percentage;
clear_line();
printf(HIGHLIGHT"%s", filename);
if (num_files > 1)
printf(" (file %i of %i)", current_file, num_files);
printf(" lines %i-%i/%i ",
cur_fline + 1, cur_fline + max_displayed_line + 1,
max_fline + 1);
if (cur_fline >= max_fline - max_displayed_line) {
printf("(END)"NORMAL);
if (num_files > 1 && current_file != num_files)
printf(HIGHLIGHT" - next: %s"NORMAL, files[current_file]);
return;
}
percentage = calc_percent();
printf("%i%%"NORMAL, percentage);
}
#endif
/* Print the status line */
static void status_print(void)
{
const char *p;
/* Change the status if flags have been set */
#if ENABLE_FEATURE_LESS_FLAGS
if (option_mask32 & (FLAG_M|FLAG_m)) {
m_status_print();
return;
}
/* No flags set */
#endif
clear_line();
if (cur_fline && cur_fline < max_fline - max_displayed_line) {
bb_putchar(':');
return;
}
p = "(END)";
if (!cur_fline)
p = filename;
if (num_files > 1) {
printf(HIGHLIGHT"%s (file %i of %i)"NORMAL,
p, current_file, num_files);
return;
}
print_hilite(p);
}
static void cap_cur_fline(int nlines)
{
int diff;
if (cur_fline < 0)
cur_fline = 0;
if (cur_fline + max_displayed_line > max_fline + TILDES) {
cur_fline -= nlines;
if (cur_fline < 0)
cur_fline = 0;
diff = max_fline - (cur_fline + max_displayed_line) + TILDES;
/* As the number of lines requested was too large, we just move
to the end of the file */
if (diff > 0)
cur_fline += diff;
}
}
static const char controls[] ALIGN1 =
/* NUL: never encountered; TAB: not converted */
/**/"\x01\x02\x03\x04\x05\x06\x07\x08" "\x0a\x0b\x0c\x0d\x0e\x0f"
"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
"\x7f\x9b"; /* DEL and infamous Meta-ESC :( */
static const char ctrlconv[] ALIGN1 =
/* '\n': it's a former NUL - subst with '@', not 'J' */
"\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x40\x4b\x4c\x4d\x4e\x4f"
"\x50\x51\x52\x53\x54\x55\x56\x57\x58\x59\x5a\x5b\x5c\x5d\x5e\x5f";
#if ENABLE_FEATURE_LESS_REGEXP
static void print_found(const char *line)
{
int match_status;
int eflags;
char *growline;
regmatch_t match_structs;
char buf[width];
const char *str = line;
char *p = buf;
size_t n;
while (*str) {
n = strcspn(str, controls);
if (n) {
if (!str[n]) break;
memcpy(p, str, n);
p += n;
str += n;
}
n = strspn(str, controls);
memset(p, '.', n);
p += n;
str += n;
}
strcpy(p, str);
/* buf[] holds quarantined version of str */
/* Each part of the line that matches has the HIGHLIGHT
and NORMAL escape sequences placed around it.
NB: we regex against line, but insert text
from quarantined copy (buf[]) */
str = buf;
growline = NULL;
eflags = 0;
goto start;
while (match_status == 0) {
char *new = xasprintf("%s%.*s"HIGHLIGHT"%.*s"NORMAL,
growline ? : "",
match_structs.rm_so, str,
match_structs.rm_eo - match_structs.rm_so,
str + match_structs.rm_so);
free(growline); growline = new;
str += match_structs.rm_eo;
line += match_structs.rm_eo;
eflags = REG_NOTBOL;
start:
/* Most of the time doesn't find the regex, optimize for that */
match_status = regexec(&pattern, line, 1, &match_structs, eflags);
}
if (!growline) {
printf(CLEAR_2_EOL"%s\n", str);
return;
}
printf(CLEAR_2_EOL"%s%s\n", growline, str);
free(growline);
}
#else
void print_found(const char *line);
#endif
static void print_ascii(const char *str)
{
char buf[width];
char *p;
size_t n;
printf(CLEAR_2_EOL);
while (*str) {
n = strcspn(str, controls);
if (n) {
if (!str[n]) break;
printf("%.*s", (int) n, str);
str += n;
}
n = strspn(str, controls);
p = buf;
do {
if (*str == 0x7f)
*p++ = '?';
else if (*str == (char)0x9b)
/* VT100's CSI, aka Meta-ESC. Who's inventor? */
/* I want to know who committed this sin */
*p++ = '{';
else
*p++ = ctrlconv[(unsigned char)*str];
str++;
} while (--n);
*p = '\0';
print_hilite(buf);
}
puts(str);
}
/* Print the buffer */
static void buffer_print(void)
{
int i;
move_cursor(0, 0);
for (i = 0; i <= max_displayed_line; i++)
if (pattern_valid)
print_found(buffer[i]);
else
print_ascii(buffer[i]);
status_print();
}
static void buffer_fill_and_print(void)
{
int i;
for (i = 0; i <= max_displayed_line && cur_fline + i <= max_fline; i++) {
buffer[i] = flines[cur_fline + i];
}
for (; i <= max_displayed_line; i++) {
buffer[i] = empty_line_marker;
}
buffer_print();
}
/* Move the buffer up and down in the file in order to scroll */
static void buffer_down(int nlines)
{
cur_fline += nlines;
read_lines();
cap_cur_fline(nlines);
buffer_fill_and_print();
}
static void buffer_up(int nlines)
{
cur_fline -= nlines;
if (cur_fline < 0) cur_fline = 0;
read_lines();
buffer_fill_and_print();
}
static void buffer_line(int linenum)
{
if (linenum < 0)
linenum = 0;
cur_fline = linenum;
read_lines();
if (linenum + max_displayed_line > max_fline)
linenum = max_fline - max_displayed_line + TILDES;
if (linenum < 0)
linenum = 0;
cur_fline = linenum;
buffer_fill_and_print();
}
static void open_file_and_read_lines(void)
{
if (filename) {
int fd = xopen(filename, O_RDONLY);
dup2(fd, 0);
if (fd) close(fd);
} else {
/* "less" with no arguments in argv[] */
/* For status line only */
filename = xstrdup(bb_msg_standard_input);
}
readpos = 0;
readeof = 0;
linepos = 0;
terminated = 1;
read_lines();
}
/* Reinitialize everything for a new file - free the memory and start over */
static void reinitialize(void)
{
int i;
if (flines) {
for (i = 0; i <= max_fline; i++)
free((void*)(flines[i]));
free(flines);
flines = NULL;
}
max_fline = -1;
cur_fline = 0;
max_lineno = 0;
open_file_and_read_lines();
buffer_fill_and_print();
}
static void getch_nowait(char* input, int sz)
{
ssize_t rd;
fd_set readfds;
again:
fflush(stdout);
/* NB: select returns whenever read will not block. Therefore:
* (a) with O_NONBLOCK'ed fds select will return immediately
* (b) if eof is reached, select will also return
* because read will immediately return 0 bytes.
* Even if select says that input is available, read CAN block
* (switch fd into O_NONBLOCK'ed mode to avoid it)
*/
FD_ZERO(&readfds);
if (max_fline <= cur_fline + max_displayed_line
&& eof_error > 0 /* did NOT reach eof yet */
) {
/* We are interested in stdin */
FD_SET(0, &readfds);
}
FD_SET(kbd_fd, &readfds);
tcsetattr(kbd_fd, TCSANOW, &term_less);
select(kbd_fd + 1, &readfds, NULL, NULL, NULL);
input[0] = '\0';
ndelay_on(kbd_fd);
rd = read(kbd_fd, input, sz);
ndelay_off(kbd_fd);
if (rd < 0) {
/* No keyboard input, but we have input on stdin! */
if (errno != EAGAIN) /* Huh?? */
return;
read_lines();
buffer_fill_and_print();
goto again;
}
}
/* Grab a character from input without requiring the return key. If the
* character is ASCII \033, get more characters and assign certain sequences
* special return codes. Note that this function works best with raw input. */
static int less_getch(void)
{
char input[16];
unsigned i;
again:
memset(input, 0, sizeof(input));
getch_nowait(input, sizeof(input));
/* Detect escape sequences (i.e. arrow keys) and handle
* them accordingly */
if (input[0] == '\033' && input[1] == '[') {
set_tty_cooked();
i = input[2] - REAL_KEY_UP;
if (i < 4)
return 20 + i;
i = input[2] - REAL_PAGE_UP;
if (i < 4)
return 24 + i;
if (input[2] == REAL_KEY_HOME_XTERM)
return KEY_HOME;
if (input[2] == REAL_KEY_HOME_ALT)
return KEY_HOME;
if (input[2] == REAL_KEY_END_XTERM)
return KEY_END;
if (input[2] == REAL_KEY_END_ALT)
return KEY_END;
return 0;
}
/* Reject almost all control chars */
i = input[0];
if (i < ' ' && i != 0x0d && i != 8) goto again;
set_tty_cooked();
return i;
}
static char* less_gets(int sz)
{
char c;
int i = 0;
char *result = xzalloc(1);
while (1) {
fflush(stdout);
/* I be damned if I know why is it needed *repeatedly*,
* but it is needed. Is it because of stdio? */
tcsetattr(kbd_fd, TCSANOW, &term_less);
c = '\0';
read(kbd_fd, &c, 1);
if (c == 0x0d)
return result;
if (c == 0x7f)
c = 8;
if (c == 8 && i) {
printf("\x8 \x8");
i--;
}
if (c < ' ')
continue;
if (i >= width - sz - 1)
continue; /* len limit */
bb_putchar(c);
result[i++] = c;
result = xrealloc(result, i+1);
result[i] = '\0';
}
}
static void examine_file(void)
{
print_statusline("Examine: ");
free(filename);
filename = less_gets(sizeof("Examine: ")-1);
/* files start by = argv. why we assume that argv is infinitely long??
files[num_files] = filename;
current_file = num_files + 1;
num_files++; */
files[0] = filename;
num_files = current_file = 1;
reinitialize();
}
/* This function changes the file currently being paged. direction can be one of the following:
* -1: go back one file
* 0: go to the first file
* 1: go forward one file */
static void change_file(int direction)
{
if (current_file != ((direction > 0) ? num_files : 1)) {
current_file = direction ? current_file + direction : 1;
free(filename);
filename = xstrdup(files[current_file - 1]);
reinitialize();
} else {
print_statusline(direction > 0 ? "No next file" : "No previous file");
}
}
static void remove_current_file(void)
{
int i;
if (num_files < 2)
return;
if (current_file != 1) {
change_file(-1);
for (i = 3; i <= num_files; i++)
files[i - 2] = files[i - 1];
num_files--;
} else {
change_file(1);
for (i = 2; i <= num_files; i++)
files[i - 2] = files[i - 1];
num_files--;
current_file--;
}
}
static void colon_process(void)
{
int keypress;
/* Clear the current line and print a prompt */
print_statusline(" :");
keypress = less_getch();
switch (keypress) {
case 'd':
remove_current_file();
break;
case 'e':
examine_file();
break;
#if ENABLE_FEATURE_LESS_FLAGS
case 'f':
m_status_print();
break;
#endif
case 'n':
change_file(1);
break;
case 'p':
change_file(-1);
break;
case 'q':
less_exit(0);
break;
case 'x':
change_file(0);
break;
}
}
#if ENABLE_FEATURE_LESS_REGEXP
static void normalize_match_pos(int match)
{
if (match >= num_matches)
match = num_matches - 1;
if (match < 0)
match = 0;
match_pos = match;
}
static void goto_match(int match)
{
int sv;
if (!pattern_valid)
return;
if (match < 0)
match = 0;
sv = cur_fline;
/* Try to find next match if eof isn't reached yet */
if (match >= num_matches && eof_error > 0) {
cur_fline = MAXLINES; /* look as far as needed */
read_lines();
}
if (num_matches) {
cap_cur_fline(cur_fline);
normalize_match_pos(match);
buffer_line(match_lines[match_pos]);
} else {
cur_fline = sv;
print_statusline("No matches found");
}
}
static void fill_match_lines(unsigned pos)
{
if (!pattern_valid)
return;
/* Run the regex on each line of the current file */
while (pos <= max_fline) {
/* If this line matches */
if (regexec(&pattern, flines[pos], 0, NULL, 0) == 0
/* and we didn't match it last time */
&& !(num_matches && match_lines[num_matches-1] == pos)
) {
match_lines = xrealloc(match_lines, (num_matches+1) * sizeof(int));
match_lines[num_matches++] = pos;
}
pos++;
}
}
static void regex_process(void)
{
char *uncomp_regex, *err;
/* Reset variables */
free(match_lines);
match_lines = NULL;
match_pos = 0;
num_matches = 0;
if (pattern_valid) {
regfree(&pattern);
pattern_valid = 0;
}
/* Get the uncompiled regular expression from the user */
clear_line();
bb_putchar((option_mask32 & LESS_STATE_MATCH_BACKWARDS) ? '?' : '/');
uncomp_regex = less_gets(1);
if (!uncomp_regex[0]) {
free(uncomp_regex);
buffer_print();
return;
}
/* Compile the regex and check for errors */
err = regcomp_or_errmsg(&pattern, uncomp_regex, 0);
free(uncomp_regex);
if (err) {
print_statusline(err);
free(err);
return;
}
pattern_valid = 1;
match_pos = 0;
fill_match_lines(0);
while (match_pos < num_matches) {
if (match_lines[match_pos] > cur_fline)
break;
match_pos++;
}
if (option_mask32 & LESS_STATE_MATCH_BACKWARDS)
match_pos--;
/* It's possible that no matches are found yet.
* goto_match() will read input looking for match,
* if needed */
goto_match(match_pos);
}
#endif
static void number_process(int first_digit)
{
int i = 1;
int num;
char num_input[sizeof(int)*4]; /* more than enough */
char keypress;
num_input[0] = first_digit;
/* Clear the current line, print a prompt, and then print the digit */
clear_line();
printf(":%c", first_digit);
/* Receive input until a letter is given */
while (i < sizeof(num_input)-1) {
num_input[i] = less_getch();
if (!num_input[i] || !isdigit(num_input[i]))
break;
bb_putchar(num_input[i]);
i++;
}
/* Take the final letter out of the digits string */
keypress = num_input[i];
num_input[i] = '\0';
num = bb_strtou(num_input, NULL, 10);
/* on format error, num == -1 */
if (num < 1 || num > MAXLINES) {
buffer_print();
return;
}
/* We now know the number and the letter entered, so we process them */
switch (keypress) {
case KEY_DOWN: case 'z': case 'd': case 'e': case ' ': case '\015':
buffer_down(num);
break;
case KEY_UP: case 'b': case 'w': case 'y': case 'u':
buffer_up(num);
break;
case 'g': case '<': case 'G': case '>':
cur_fline = num + max_displayed_line;
read_lines();
buffer_line(num - 1);
break;
case 'p': case '%':
num = num * (max_fline / 100); /* + max_fline / 2; */
cur_fline = num + max_displayed_line;
read_lines();
buffer_line(num);
break;
#if ENABLE_FEATURE_LESS_REGEXP
case 'n':
goto_match(match_pos + num);
break;
case '/':
option_mask32 &= ~LESS_STATE_MATCH_BACKWARDS;
regex_process();
break;
case '?':
option_mask32 |= LESS_STATE_MATCH_BACKWARDS;
regex_process();
break;
#endif
}
}
#if ENABLE_FEATURE_LESS_FLAGCS
static void flag_change(void)
{
int keypress;
clear_line();
bb_putchar('-');
keypress = less_getch();
switch (keypress) {
case 'M':
option_mask32 ^= FLAG_M;
break;
case 'm':
option_mask32 ^= FLAG_m;
break;
case 'E':
option_mask32 ^= FLAG_E;
break;
case '~':
option_mask32 ^= FLAG_TILDE;
break;
}
}
static void show_flag_status(void)
{
int keypress;
int flag_val;
clear_line();
bb_putchar('_');
keypress = less_getch();
switch (keypress) {
case 'M':
flag_val = option_mask32 & FLAG_M;
break;
case 'm':
flag_val = option_mask32 & FLAG_m;
break;
case '~':
flag_val = option_mask32 & FLAG_TILDE;
break;
case 'N':
flag_val = option_mask32 & FLAG_N;
break;
case 'E':
flag_val = option_mask32 & FLAG_E;
break;
default:
flag_val = 0;
break;
}
clear_line();
printf(HIGHLIGHT"The status of the flag is: %u"NORMAL, flag_val != 0);
}
#endif
static void save_input_to_file(void)
{
const char *msg = "";
char *current_line;
int i;
FILE *fp;
print_statusline("Log file: ");
current_line = less_gets(sizeof("Log file: ")-1);
if (strlen(current_line) > 0) {
fp = fopen(current_line, "w");
if (!fp) {
msg = "Error opening log file";
goto ret;
}
for (i = 0; i <= max_fline; i++)
fprintf(fp, "%s\n", flines[i]);
fclose(fp);
msg = "Done";
}
ret:
print_statusline(msg);
free(current_line);
}
#if ENABLE_FEATURE_LESS_MARKS
static void add_mark(void)
{
int letter;
print_statusline("Mark: ");
letter = less_getch();
if (isalpha(letter)) {
/* If we exceed 15 marks, start overwriting previous ones */
if (num_marks == 14)
num_marks = 0;
mark_lines[num_marks][0] = letter;
mark_lines[num_marks][1] = cur_fline;
num_marks++;
} else {
print_statusline("Invalid mark letter");
}
}
static void goto_mark(void)
{
int letter;
int i;
print_statusline("Go to mark: ");
letter = less_getch();
clear_line();
if (isalpha(letter)) {
for (i = 0; i <= num_marks; i++)
if (letter == mark_lines[i][0]) {
buffer_line(mark_lines[i][1]);
break;
}
if (num_marks == 14 && letter != mark_lines[14][0])
print_statusline("Mark not set");
} else
print_statusline("Invalid mark letter");
}
#endif
#if ENABLE_FEATURE_LESS_BRACKETS
static char opp_bracket(char bracket)
{
switch (bracket) {
case '{': case '[':
return bracket + 2;
case '(':
return ')';
case '}': case ']':
return bracket - 2;
case ')':
return '(';
}
return 0;
}
static void match_right_bracket(char bracket)
{
int bracket_line = -1;
int i;
if (strchr(flines[cur_fline], bracket) == NULL) {
print_statusline("No bracket in top line");
return;
}
for (i = cur_fline + 1; i < max_fline; i++) {
if (strchr(flines[i], opp_bracket(bracket)) != NULL) {
bracket_line = i;
break;
}
}
if (bracket_line == -1)
print_statusline("No matching bracket found");
buffer_line(bracket_line - max_displayed_line);
}
static void match_left_bracket(char bracket)
{
int bracket_line = -1;
int i;
if (strchr(flines[cur_fline + max_displayed_line], bracket) == NULL) {
print_statusline("No bracket in bottom line");
return;
}
for (i = cur_fline + max_displayed_line; i >= 0; i--) {
if (strchr(flines[i], opp_bracket(bracket)) != NULL) {
bracket_line = i;
break;
}
}
if (bracket_line == -1)
print_statusline("No matching bracket found");
buffer_line(bracket_line);
}
#endif /* FEATURE_LESS_BRACKETS */
static void keypress_process(int keypress)
{
switch (keypress) {
case KEY_DOWN: case 'e': case 'j': case 0x0d:
buffer_down(1);
break;
case KEY_UP: case 'y': case 'k':
buffer_up(1);
break;
case PAGE_DOWN: case ' ': case 'z':
buffer_down(max_displayed_line + 1);
break;
case PAGE_UP: case 'w': case 'b':
buffer_up(max_displayed_line + 1);
break;
case 'd':
buffer_down((max_displayed_line + 1) / 2);
break;
case 'u':
buffer_up((max_displayed_line + 1) / 2);
break;
case KEY_HOME: case 'g': case 'p': case '<': case '%':
buffer_line(0);
break;
case KEY_END: case 'G': case '>':
cur_fline = MAXLINES;
read_lines();
buffer_line(cur_fline);
break;
case 'q': case 'Q':
less_exit(0);
break;
#if ENABLE_FEATURE_LESS_MARKS
case 'm':
add_mark();
buffer_print();
break;
case '\'':
goto_mark();
buffer_print();
break;
#endif
case 'r': case 'R':
buffer_print();
break;
/*case 'R':
full_repaint();
break;*/
case 's':
save_input_to_file();
break;
case 'E':
examine_file();
break;
#if ENABLE_FEATURE_LESS_FLAGS
case '=':
m_status_print();
break;
#endif
#if ENABLE_FEATURE_LESS_REGEXP
case '/':
option_mask32 &= ~LESS_STATE_MATCH_BACKWARDS;
regex_process();
break;
case 'n':
goto_match(match_pos + 1);
break;
case 'N':
goto_match(match_pos - 1);
break;
case '?':
option_mask32 |= LESS_STATE_MATCH_BACKWARDS;
regex_process();
break;
#endif
#if ENABLE_FEATURE_LESS_FLAGCS
case '-':
flag_change();
buffer_print();
break;
case '_':
show_flag_status();
break;
#endif
#if ENABLE_FEATURE_LESS_BRACKETS
case '{': case '(': case '[':
match_right_bracket(keypress);
break;
case '}': case ')': case ']':
match_left_bracket(keypress);
break;
#endif
case ':':
colon_process();
break;
}
if (isdigit(keypress))
number_process(keypress);
}
static void sig_catcher(int sig ATTRIBUTE_UNUSED)
{
set_tty_cooked();
exit(1);
}
int less_main(int argc, char **argv);
int less_main(int argc, char **argv)
{
int keypress;
INIT_G();
/* TODO: -x: do not interpret backspace, -xx: tab also */
/* -xxx: newline also */
/* -w N: assume width N (-xxx -w 32: hex viewer of sorts) */
getopt32(argv, "EMmN~");
argc -= optind;
argv += optind;
num_files = argc;
files = 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);
kbd_fd = open(CURRENT_TTY, O_RDONLY);
if (kbd_fd < 0)
return bb_cat(argv);
if (!num_files) {
if (isatty(STDIN_FILENO)) {
/* Just "less"? No args and no redirection? */
bb_error_msg("missing filename");
bb_show_usage();
}
} else
filename = xstrdup(files[0]);
get_terminal_width_height(kbd_fd, &width, &max_displayed_line);
/* 20: two tabstops + 4 */
if (width < 20 || max_displayed_line < 3)
bb_error_msg_and_die("too narrow here");
max_displayed_line -= 2;
buffer = xmalloc((max_displayed_line+1) * sizeof(char *));
if (option_mask32 & FLAG_TILDE)
empty_line_marker = "";
tcgetattr(kbd_fd, &term_orig);
signal(SIGTERM, sig_catcher);
signal(SIGINT, sig_catcher);
term_less = term_orig;
term_less.c_lflag &= ~(ICANON | ECHO);
term_less.c_iflag &= ~(IXON | ICRNL);
/*term_less.c_oflag &= ~ONLCR;*/
term_less.c_cc[VMIN] = 1;
term_less.c_cc[VTIME] = 0;
/* Want to do it just once, but it doesn't work, */
/* so we are redoing it (see code above). Mystery... */
/*tcsetattr(kbd_fd, TCSANOW, &term_less);*/
reinitialize();
while (1) {
keypress = less_getch();
keypress_process(keypress);
}
}