New applet "less", from Rob Sullivan.

1 files changed, 1262 insertions, 0 deletions

diff --git a/miscutils/less.c b/miscutils/less.c
new file mode 100644
index 000000000..43bc6737e
--- /dev/null
+++ b/miscutils/less.c
@@ -0,0 +1,1262 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Mini less implementation for busybox
+ *
+ *
+ * Copyright (C) 2005 by Rob Sullivan <cogito.ergo.cogito@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307 USA
+ *
+ *      This program needs a lot of development, so consider it in a beta stage
+ *      at best.
+ *
+ *      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.
+ *      - Check for binary files, and prompt the user if a binary file
+ *      is detected.
+ *      - Allow horizontal scrolling. Currently, lines simply continue onto
+ *      the next line, per the terminal's discretion
+ *
+ *      Notes:
+ *      - filename is an array and not a pointer because that avoids all sorts
+ *      of complications involving the fact that something that is pointed to
+ *      will be changed if the pointer is changed.
+ *      - the inp file pointer is used so that keyboard input works after
+ *      redirected input has been read from stdin
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <regex.h>
+#include <ctype.h>
+#include "busybox.h"
+
+/* These are the escape sequences corresponding to special keys */
+#define REAL_KEY_UP 'A'
+#define REAL_KEY_DOWN 'B'
+#define REAL_KEY_RIGHT 'C'
+#define REAL_KEY_LEFT 'D'
+#define REAL_PAGE_UP '5'
+#define REAL_PAGE_DOWN '6'
+
+/* These are the special codes assigned by this program to the special keys */
+#define PAGE_UP 20
+#define PAGE_DOWN 21
+#define KEY_UP 22
+#define KEY_DOWN 23
+#define KEY_RIGHT 24
+#define KEY_LEFT 25
+
+/* 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[2J"
+
+/* Maximum number of lines in a file */
+#define MAXLINES 10000
+
+/* Get height and width of terminal */
+#define tty_width_height()              get_terminal_width_height(0, &width, &height)
+
+/* Function prototypes */
+static void set_tty_cooked(void);
+static void set_tty_raw(void);
+static void tless_exit(int code);
+static int tless_getch(void);
+static void move_cursor(int x, int y);
+static void clear_line(void);
+static void data_readlines(void);
+static void free_flines(void);
+#ifdef CONFIG_FEATURE_LESS_FLAGS
+static int calc_percent(void);
+#endif
+static int reverse_percent(int percentage);
+#ifdef CONFIG_FEATURE_LESS_FLAGS
+static void m_status_print(void);
+static void medium_status_print(void);
+#endif
+static void status_print(void);
+static void buffer_print(void);
+static void buffer_init(void);
+static void buffer_down(int nlines);
+static void buffer_up(int nlines);
+static void buffer_line(int linenum);
+static void keypress_process(int keypress);
+static void colon_process(void);
+static void number_process(int first_digit);
+#ifdef CONFIG_FEATURE_LESS_FLAGCS
+static void flag_change(void);
+static void show_flag_status(void);
+#endif
+static void examine_file(void);
+static void next_file(void);
+static void previous_file(void);
+static void first_file(void);
+static void remove_current_file(void);
+static void full_repaint(void);
+static void add_linenumbers(void);
+static void save_input_to_file(void);
+#ifdef CONFIG_FEATURE_LESS_MARKS
+static void     add_mark(void);
+static void goto_mark(void);
+#endif
+#ifdef CONFIG_FEATURE_LESS_REGEXP
+static void regex_process(void);
+char *process_regex_on_line(char *line, regex_t *pattern);
+char *insert_highlights(char *line, int start, int end);
+static void goto_match (int match);
+static void search_backwards(void);
+#endif
+#ifdef CONFIG_FEATURE_LESS_BRACKETS
+static char opp_bracket (char bracket);
+static void match_right_bracket (char bracket);
+static void match_left_bracket (char bracket);
+#endif
+int less_main(int argc, char *argv[]);
+
+static int height;
+static int width;
+static char **files;
+static char filename[256];
+static char buffer[100][256];
+static char *flines[MAXLINES];
+static int current_file = 1;
+static int line_pos = 0;
+static int num_flines;
+static int num_files = 1;
+static int past_eof = 0;
+
+/* Command line options */
+static int E_FLAG = 0;
+static int M_FLAG = 0;
+static int N_FLAG = 0;
+static int m_FLAG = 0;
+static int TILDE_FLAG = 0;
+
+/* This is needed so that program behaviour changes when input comes from
+   stdin */
+static int inp_stdin = 0;
+/* This is required so that when a file is requested to be examined after
+   input has come from stdin (e.g. dmesg | less), the input stream from 
+   the keyboard still stays the same. If it switched back to stdin, keyboard
+   input wouldn't work. */
+static int ea_inp_stdin = 0;
+
+#ifdef CONFIG_FEATURE_LESS_MARKS
+static int mark_lines[15][2];
+static int num_marks = 0;
+#endif
+
+#ifdef CONFIG_FEATURE_LESS_REGEXP
+static int match_found = 0;
+static int match_lines[100];
+static int match_pos = 0;
+static int num_matches = 0;
+static int match_backwards = 0;
+static int num_back_match = 1;
+#endif
+
+/* Needed termios structures */
+static struct termios term_orig, term_vi;
+
+/* File pointer to get input from */
+static FILE *inp;
+
+/* Reset terminal input to normal */
+static void set_tty_cooked() {
+        fflush(stdout);
+        tcsetattr(0, TCSANOW, &term_orig);
+}
+
+/* Set terminal input to raw mode */
+static void set_tty_raw() {
+       tcgetattr(0, &term_orig);
+        term_vi = term_orig;
+        term_vi.c_lflag &= (~ICANON & ~ECHO); 
+        term_vi.c_iflag &= (~IXON & ~ICRNL);
+        term_vi.c_oflag &= (~ONLCR);
+        term_vi.c_cc[VMIN] = 1;
+        term_vi.c_cc[VTIME] = 0;
+        tcsetattr(0, TCSANOW, &term_vi);
+}
+
+/* Exit the program gracefully */
+static void tless_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? */
+        
+        putchar('\n');
+        exit(code);
+}
+
+/* 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. */ 
+int tless_getch() {
+        
+        set_tty_raw();
+        char input_key[3];
+        
+        input_key[0] = getc(inp);
+        /* Detect escape sequences (i.e. arrow keys) and handle
+           them accordingly */
+        
+        if (input_key[0] == '\033') {
+                input_key[1] = getc(inp);
+                input_key[2] = getc(inp);
+                set_tty_cooked();
+                if (input_key[1] == '[') {
+                        if (input_key[2] == REAL_KEY_UP)
+                                return KEY_UP;
+                        else if (input_key[2] == REAL_KEY_DOWN)
+                                return KEY_DOWN;
+                        else if (input_key[2] == REAL_KEY_RIGHT)
+                                return KEY_RIGHT;
+                        else if (input_key[2] == REAL_KEY_LEFT)
+                                return KEY_LEFT;
+                        else if (input_key[2] == REAL_PAGE_UP)
+                                return PAGE_UP;
+                        else if (input_key[2] == REAL_PAGE_DOWN)
+                                return PAGE_DOWN;
+                }
+        }
+        /* The input is a normal ASCII value */
+        else {
+                set_tty_cooked();
+                return input_key[0];
+        }
+        return 0;
+}
+
+/* Move the cursor to a position (x,y), where (0,0) is the 
+   top-left corner of the console */
+static void move_cursor(int x, int y) {
+        printf("\033[%i;%iH", x, y);
+}
+
+static void clear_line() {
+        move_cursor(height, 0);
+        printf("\033[K");
+}
+
+static void data_readlines() {
+        
+        int i;
+        char current_line[256];
+        FILE *fp;
+        
+        fp = (inp_stdin) ? stdin : bb_xfopen(filename, "rt");
+        
+        for (i = 0; (!feof(fp)) && (i <= MAXLINES); i++) {
+                strcpy(current_line, "");
+                fgets(current_line, 256, fp);
+                bb_xferror(fp, filename);
+                flines[i] = (char *) bb_xstrndup(current_line, (strlen(current_line) + 1) * sizeof(char));
+        }
+        num_flines = i - 2;
+
+/* Reset variables for a new file */
+        
+        line_pos = 0;
+        past_eof = 0;
+        
+        fclose(fp);
+
+        if (inp_stdin)
+                inp = fopen(CURRENT_TTY, "r");
+        else
+                inp = stdin;
+
+        if (ea_inp_stdin) {
+                fclose(inp);
+                inp = fopen(CURRENT_TTY, "r");
+        }
+        
+        if (N_FLAG)
+                add_linenumbers();
+}
+
+/* Free the file data */
+static void free_flines() {
+        
+        int i;
+        
+        for (i = 0; i <= num_flines; i++)
+                free(flines[i]);
+}
+
+#ifdef CONFIG_FEATURE_LESS_FLAGS
+/* Calculate the percentage the current line position is through the file */
+int calc_percent() {
+        return ((100 * (line_pos + height - 2) / num_flines) + 1);
+}
+#endif
+
+/* Turn a percentage into a line number */
+int reverse_percent(int percentage) {
+        double linenum = percentage;
+        linenum = ((linenum / 100) * num_flines) - 1;
+        return(linenum);
+}
+
+#ifdef CONFIG_FEATURE_LESS_FLAGS
+/* Print a status line if -M was specified */
+static void m_status_print() {
+
+        int percentage;
+        
+        if (!past_eof) {
+                if (!line_pos) {
+                        if (num_files > 1)
+                                printf("%s%s %s%i%s%i%s%i-%i/%i ", HIGHLIGHT, filename, "(file ", current_file, " of ", num_files, ") lines ", line_pos + 1, line_pos + height - 1, num_flines + 1);
+                        else {
+                                printf("%s%s lines %i-%i/%i ", HIGHLIGHT, filename, line_pos + 1, line_pos + height - 1, num_flines + 1);
+                        }
+                }
+                else {
+                        printf("%s %s lines %i-%i/%i ", HIGHLIGHT, filename, line_pos + 1, line_pos + height - 1, num_flines + 1);
+                }
+        
+                if (line_pos == num_flines - height + 2) {
+                        printf("(END) %s", NORMAL);
+                        if ((num_files > 1) && (current_file != num_files))
+                                printf("%s- Next: %s%s", HIGHLIGHT, files[current_file], NORMAL);
+                }
+                else {
+                        percentage = calc_percent();
+                        printf("%i%s %s", percentage, "%", NORMAL);
+                }
+        }
+        else {
+                printf("%s%s lines %i-%i/%i (END) ", HIGHLIGHT, filename, line_pos + 1, num_flines + 1, num_flines + 1);
+                if ((num_files > 1) && (current_file != num_files))
+                        printf("- Next: %s", files[current_file]);
+                printf("%s", NORMAL);
+        }
+}
+
+/* Print a status line if -m was specified */
+static void medium_status_print() {
+
+        int percentage;
+        percentage = calc_percent();
+        
+        if (!line_pos)
+                printf("%s%s %i%s%s", HIGHLIGHT, filename, percentage, "%", NORMAL);
+        else if (line_pos == num_flines - height + 2)
+                printf("%s(END)%s", HIGHLIGHT, NORMAL);
+        else
+                printf("%s%i%s%s", HIGHLIGHT, percentage, "%", NORMAL);
+}
+#endif
+
+/* Print the status line */
+static void status_print() {
+        
+        /* Change the status if flags have been set */
+#ifdef CONFIG_FEATURE_LESS_FLAGS        
+        if (M_FLAG)     
+                m_status_print();
+        else if (m_FLAG)
+                medium_status_print();
+        /* No flags set */
+        else {
+#endif
+                if (!line_pos) {
+                        printf("%s%s %s", HIGHLIGHT, filename, NORMAL);
+                        if (num_files > 1)
+                                printf("%s%s%i%s%i%s%s", HIGHLIGHT, "(file ", current_file, " of ", num_files, ")", NORMAL);
+                }
+                else if (line_pos == num_flines - height + 2) {
+                        printf("%s%s %s", HIGHLIGHT, "(END)", NORMAL);
+                        if ((num_files > 1) && (current_file != num_files))
+                                printf("%s%s%s%s", HIGHLIGHT, "- Next: ", files[current_file], NORMAL);
+                }
+                else {
+                        printf("%c", ':');
+                }
+#ifdef CONFIG_FEATURE_LESS_FLAGS
+        }
+#endif
+}
+
+/* Print the buffer */
+static void buffer_print() {
+        
+        int i;
+        
+        if (num_flines >= height - 2) {
+                printf("%s", CLEAR);
+                move_cursor(0,0);
+                for (i = 0; i < height - 1; i++)
+                        printf("%s", buffer[i]);
+                status_print();
+        }
+        else {
+                printf("%s", CLEAR);
+                move_cursor(0,0);
+                for (i = 1; i < (height - 1 - num_flines); i++)
+                        putchar('\n');
+                for (i = 0; i < height - 1; i++)
+                        printf("%s", buffer[i]);
+                status_print();
+        }
+}
+
+/* Initialise the buffer */
+static void buffer_init() {
+        
+        int i;
+        
+        for (i = 0; i < (height - 1); i++)
+                memset(buffer[i], '\0', 256);
+        
+        /* Fill the buffer until the end of the file or the 
+           end of the buffer is reached */
+        for (i = 0; (i < (height - 1)) && (i <= num_flines); i++) {
+                strcpy(buffer[i], flines[i]);
+        }
+        
+        /* If the buffer still isn't full, fill it with blank lines */
+        for (; i < (height - 1); i++) {
+                strcpy(buffer[i], "");
+        }
+}
+
+/* Move the buffer up and down in the file in order to scroll */
+static void buffer_down(int nlines) {
+        
+        int i;
+        
+        if (!past_eof) {
+                if (line_pos + (height - 3) + nlines < num_flines) {
+                        line_pos += nlines;
+                        for (i = 0; i < (height - 1); i++)
+                                strcpy(buffer[i], flines[line_pos + i]);
+                }
+                else {
+                        /* As the number of lines requested was too large, we just move
+                        to the end of the file */
+                        while (line_pos + (height - 3) + 1 < num_flines) {      
+                                line_pos += 1;
+                                for (i = 0; i < (height - 1); i++)
+                                        strcpy(buffer[i], flines[line_pos + i]);
+                        }
+                }
+
+                /* We exit if the -E flag has been set */
+                if (E_FLAG && (line_pos + (height - 2) == num_flines))
+                        tless_exit(0);
+        }
+}
+
+static void buffer_up(int nlines) {
+        
+        int i;
+        int tilde_line;
+        
+        if (!past_eof) {
+                if (line_pos - nlines >= 0) {
+                        line_pos -= nlines;
+                        for (i = 0; i < (height - 1); i++)
+                                strcpy(buffer[i], flines[line_pos + i]);
+                }
+                else {
+                /* As the requested number of lines to move was too large, we
+                   move one line up at a time until we can't. */
+                        while (line_pos != 0) {
+                                line_pos -= 1;
+                                for (i = 0; i < (height - 1); i++)
+                                        strcpy(buffer[i], flines[line_pos + i]);
+                        }
+                }
+        }
+        else {
+                /* Work out where the tildes start */
+                tilde_line = num_flines - line_pos + 3;
+                
+                line_pos -= nlines;
+                /* Going backwards nlines lines has taken us to a point where
+                   nothing is past the EOF, so we revert to normal. */
+                if (line_pos < num_flines - height + 3) {
+                        past_eof = 0;
+                        buffer_up(nlines);
+                }
+                else {
+                        /* We only move part of the buffer, as the rest
+                        is past the EOF */
+                        for (i = 0; i < (height - 1); i++) {
+                                if (i < tilde_line - nlines + 1)
+                                        strcpy(buffer[i], flines[line_pos + i]);
+                                else {
+                                        if (line_pos >= num_flines - height + 2)
+                                                strcpy(buffer[i], "~\n");
+                                }
+                        }
+                }               
+        }
+}
+
+static void buffer_line(int linenum) {
+        
+        int i;
+
+        past_eof = 0;
+
+        if (linenum < 1 || linenum > num_flines) {
+                clear_line();
+                printf("%s%s%i%s", HIGHLIGHT, "Cannot seek to line number ", linenum, NORMAL);
+        }
+        else if (linenum < (num_flines - height - 2)) {
+                for (i = 0; i < (height - 1); i++)
+                        strcpy(buffer[i], flines[linenum + i]);
+                line_pos = linenum;
+        }
+        else {
+                for (i = 0; i < (height - 1); i++) {
+                        if (linenum + i < num_flines + 2)
+                                strcpy(buffer[i], flines[linenum + i]);
+                        else
+                                strcpy(buffer[i], (TILDE_FLAG) ? "\n" : "~\n");
+                }
+                line_pos = linenum;
+                /* Set past_eof so buffer_down and buffer_up act differently */
+                past_eof = 1;
+        }
+}
+
+static void keypress_process(int keypress) {
+        switch (keypress) {
+                case KEY_DOWN: case 'e': case 'j': case '\015':
+                        buffer_down(1);
+                        buffer_print();
+                        break;
+                case KEY_UP: case 'y': case 'k':
+                        buffer_up(1);
+                        buffer_print();
+                        break;
+                case PAGE_DOWN: case ' ': case 'z':
+                        buffer_down(height - 1);
+                        buffer_print();
+                        break;
+                case PAGE_UP: case 'w': case 'b':
+                        buffer_up(height - 1);
+                        buffer_print();
+                        break;
+                case 'd':
+                        buffer_down((height - 1) / 2);
+                        buffer_print();
+                        break;
+                case 'u':
+                        buffer_up((height - 1) / 2);
+                        buffer_print();
+                        break;
+                case 'g': case 'p': case '<': case '%':
+                        buffer_up(num_flines + 1);
+                        buffer_print();
+                        break;
+                case 'G': case '>':
+                        buffer_down(num_flines + 1);
+                        buffer_print();
+                        break;
+                case 'q': case 'Q':
+                        tless_exit(0);
+                        break;
+#ifdef CONFIG_FEATURE_LESS_MARKS
+                case 'm':
+                        add_mark();
+                        buffer_print();
+                        break;
+                case '\'':
+                        goto_mark();
+                        buffer_print();
+                        break;
+#endif
+                case 'r':
+                        buffer_print();
+                        break;
+                case 'R':
+                        full_repaint();
+                        break;
+                case 's':
+                        if (inp_stdin)
+                                save_input_to_file();
+                        break;
+                case 'E':
+                        examine_file();
+                        break;
+#ifdef CONFIG_FEATURE_LESS_FLAGS
+                case '=':
+                        clear_line();
+                        m_status_print();
+                        break;
+#endif
+#ifdef CONFIG_FEATURE_LESS_REGEXP
+                case '/':
+                        regex_process();
+                        buffer_print();
+                        break;
+                case 'n':
+                        goto_match(match_pos + 1);
+                        buffer_print();
+                        break;
+                case 'N':
+                        goto_match(match_pos - 1);
+                        buffer_print();
+                        break;
+                case '?':
+                        search_backwards();
+                        buffer_print();
+                        break;
+#endif
+#ifdef CONFIG_FEATURE_LESS_FLAGCS
+                case '-':
+                        flag_change();
+                        buffer_print();
+                        break;
+                case '_':
+                        show_flag_status();
+                        break;
+#endif
+#ifdef CONFIG_FEATURE_LESS_BRACKETS
+                case '{': case '(': case '[':
+                        match_right_bracket(keypress);
+                        break;
+                case '}': case ')': case ']':
+                        match_left_bracket(keypress);
+                        break;
+#endif                  
+                case ':': 
+                        colon_process();
+                        break;
+                default:
+                        break;
+        }
+        if (isdigit(keypress))
+                number_process(keypress);
+}
+
+static void colon_process() {
+        
+        int keypress;
+        
+        /* Clear the current line and print a prompt */
+        clear_line();
+        printf(" :");
+        
+        keypress = tless_getch();
+        switch (keypress) {
+                case 'd':
+                        remove_current_file();
+                        break;
+                case 'e':
+                        examine_file();
+                        break;
+#ifdef CONFIG_FEATURE_LESS_FLAGS
+                case 'f':
+                        clear_line();
+                        m_status_print();
+                        break;
+#endif
+                case 'n':
+                        next_file();
+                        break;
+                case 'p':
+                        previous_file();
+                        break;
+                case 'q':
+                        tless_exit(0);
+                        break;
+                case 'x':
+                        first_file();
+                        break;
+                default:
+                        break;
+        }
+}
+
+static void number_process(int first_digit) {
+        
+        int i = 1;
+        int num;
+        char num_input[80];
+        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((num_input[i] = tless_getch()) && isdigit(num_input[i])) {
+                printf("%c",num_input[i]);
+                i++;
+        }
+        
+        /* Take the final letter out of the digits string */
+        keypress = num_input[i];
+        num_input[i] = '\0';
+        i--;
+        num = atoi(num_input);
+
+        /* 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);
+                        buffer_print();
+                        break;
+                case KEY_UP: case 'b': case 'w': case 'y': case 'u':
+                        buffer_up(num);
+                        buffer_print();
+                        break;
+                case 'g': case '<': case 'G': case '>':
+                        if (num_flines >= height - 2)
+                                buffer_line(num - 1);
+                        buffer_print();
+                        break;
+                case 'p': case '%':
+                        buffer_line(reverse_percent(num));
+                        buffer_print();
+                        break;
+#ifdef CONFIG_FEATURE_LESS_REGEXP
+                case 'n':
+                        goto_match(match_pos + num - 1);
+                        buffer_print();
+                        break;
+                case '/':
+                        regex_process();
+                        goto_match(num - 1);
+                        buffer_print();
+                        break;
+                case '?':
+                        num_back_match = num;
+                        search_backwards();
+                        buffer_print();
+                        break;
+#endif
+                default:
+                        break;
+        }
+}
+
+#ifdef CONFIG_FEATURE_LESS_FLAGCS
+static void flag_change() {
+        
+        int keypress;
+        
+        clear_line();
+        printf("-");
+        keypress = tless_getch();
+        
+        switch (keypress) {
+                case 'M':
+                        M_FLAG = !M_FLAG;
+                        break;
+                case 'm':
+                        m_FLAG = !m_FLAG;
+                        break;
+                case 'E':
+                        E_FLAG = !E_FLAG;
+                        break;
+                case '~':
+                        TILDE_FLAG = !TILDE_FLAG;
+                        break;
+                default:
+                        break;
+        }
+}
+
+static void show_flag_status() {
+        
+        int keypress;
+        int flag_val;
+        
+        clear_line();
+        printf("_");
+        keypress = tless_getch();
+
+        switch (keypress) {
+                case 'M':
+                        flag_val = M_FLAG;
+                        break;
+                case 'm':
+                        flag_val = m_FLAG;
+                        break;
+                case '~':
+                        flag_val = TILDE_FLAG;
+                        break;
+                case 'N':
+                        flag_val = N_FLAG;
+                        break;
+                case 'E':
+                        flag_val = E_FLAG;
+                        break;
+                default:
+                        flag_val = 0;
+                        break;
+        }
+        
+        clear_line();
+        printf("%s%s%i%s", HIGHLIGHT, "The status of the flag is: ", flag_val, NORMAL);
+}
+#endif
+
+static void examine_file() {
+
+        int newline_offset;
+        
+        clear_line();
+        printf("Examine: ");
+        fgets(filename, 256, inp);
+        
+        /* As fgets adds a newline to the end of an input string, we
+           need to remove it */
+        newline_offset = strlen(filename) - 1;
+        filename[newline_offset] = '\0';
+        
+        files[num_files] = bb_xstrndup(filename, (strlen(filename) + 1) * sizeof(char));
+        current_file = num_files + 1;
+        num_files++;    
+
+        inp_stdin = 0;
+        ea_inp_stdin = 1;
+        free_flines();
+        data_readlines();
+        buffer_init();
+        buffer_print();
+}
+
+static void next_file() {
+        if (current_file != num_files) {
+                current_file++;
+                strcpy(filename, files[current_file - 1]);
+                free_flines();
+                data_readlines();
+                buffer_init();
+                buffer_print();
+        }
+        else {
+                clear_line();
+                printf("%s%s%s", HIGHLIGHT, "No next file", NORMAL);
+        }
+}
+
+static void previous_file() {
+        if (current_file != 1) {
+                current_file--;
+                strcpy(filename, files[current_file - 1]);
+                
+                free_flines();
+                data_readlines();
+                buffer_init();
+                buffer_print();
+        }
+        else {
+                clear_line();
+                printf("%s%s%s", HIGHLIGHT, "No previous file", NORMAL);
+        }
+}
+
+static void first_file() {
+        if (current_file != 1) {
+                current_file = 1;
+                strcpy(filename, files[current_file - 1]);
+                free_flines();
+                data_readlines();
+                buffer_init();
+                buffer_print();
+        }
+}
+
+static void remove_current_file() {
+        
+        int i;
+        
+        if (current_file != 1) {
+                previous_file();
+                for (i = 3; i <= num_files; i++)
+                        files[i - 2] = files[i - 1];
+                num_files--;
+                buffer_print();
+        }
+        else {
+                next_file();
+                for (i = 2; i <= num_files; i++)
+                        files[i - 2] = files[i - 1];
+                num_files--;
+                current_file--;
+                buffer_print();
+        }
+}
+
+static void full_repaint() {
+
+        int temp_line_pos = line_pos;
+        data_readlines();
+        buffer_init();
+        buffer_line(temp_line_pos);
+        buffer_print();
+}
+
+/* This adds line numbers to every line, as the -N flag necessitates */
+static void add_linenumbers() {
+
+        char current_line[256];
+        int i;
+        
+        for (i = 0; i <= num_flines; i++) {
+                safe_strncpy(current_line, flines[i], 256);
+                flines[i] = xrealloc(flines[i], strlen(current_line) + 7 );
+                sprintf(flines[i],"%5d %s", i+1, current_line);
+        }
+}
+
+static void save_input_to_file() {
+        
+        char current_line[256];
+        int i;
+        FILE *fp;
+        
+        clear_line();
+        printf("Log file: ");
+        fgets(current_line, 256, inp);
+        current_line[strlen(current_line) - 1] = '\0';
+        if (strlen(current_line)) {
+                fp = bb_xfopen(current_line, "w");
+                for (i = 0; i < num_flines; i++)
+                        fprintf(fp, "%s", flines[i]);
+                fclose(fp);
+                buffer_print();
+        }
+        else
+                printf("%sNo log file%s", HIGHLIGHT, NORMAL);
+}
+
+#ifdef CONFIG_FEATURE_LESS_MARKS
+static void add_mark() {
+
+        int letter;
+        int mark_line;
+        
+        clear_line();
+        printf("Mark: ");
+        letter = tless_getch();
+        
+        if (isalpha(letter)) {
+                mark_line = line_pos;
+        
+                /* 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] = line_pos;
+                num_marks++;
+        }
+        else {
+                clear_line();
+                printf("%s%s%s", HIGHLIGHT, "Invalid mark letter", NORMAL);
+        }
+}
+
+static void goto_mark() {
+
+        int letter;
+        int i;
+        
+        clear_line();
+        printf("Go to mark: ");
+        letter = tless_getch();
+        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])) {
+                        clear_line();
+                        printf("%s%s%s", HIGHLIGHT, "Mark not set", NORMAL);
+                }               
+        }
+        else {
+                clear_line();
+                printf("%s%s%s", HIGHLIGHT, "Invalid mark letter", NORMAL);
+        }
+}
+#endif
+
+#ifdef CONFIG_FEATURE_LESS_REGEXP
+/* The below two regular expression handler functions NEED development. */
+
+/* Get a regular expression from the user, and then go through the current
+   file line by line, running a processing regex function on each one. */
+static void regex_process() {
+        
+        char uncomp_regex[100];
+        char current_line[256];
+        int i;
+        int j = 0;
+        regex_t *pattern;
+
+        /* Reset variables */
+        match_lines[0] = -1;
+        match_pos = 0;
+        num_matches = 0;
+        match_found = 0;
+        
+        pattern = (regex_t *) malloc(sizeof(regex_t));
+        memset(pattern, 0, sizeof(regex_t));
+        
+        /* Get the uncompiled regular expression from the user */
+        clear_line();
+        if (match_backwards)
+                printf("?");
+        else
+                printf("/");
+        scanf("%s", uncomp_regex);
+
+        /* Compile the regex and check for errors */
+        xregcomp(pattern, uncomp_regex, 0);
+        
+        /* Run the regex on each line of the current file here */
+        for (i = 0; i <= num_flines; i++) {
+                strcpy(current_line, process_regex_on_line(flines[i], pattern));
+                flines[i] = (char *) bb_xstrndup(current_line, sizeof(char) * (strlen(current_line)+1));
+                
+                if (match_found) {
+                        match_lines[j] = i;
+                        j++;
+                }
+        }
+
+        num_matches = j;
+        
+        if ((match_lines[0] != -1) && (num_flines > height - 2))
+                buffer_line(match_lines[0]);
+        else
+                buffer_init();
+}
+
+char *process_regex_on_line(char *line, regex_t *pattern) {
+        /* This function takes the regex and applies it to the line.
+           Each part of the line that matches has the HIGHLIGHT
+           and NORMAL escape sequences placed around it by 
+           insert_highlights, and then the line is returned. */
+        
+        int match_status;
+        char *line2 = (char *) malloc((sizeof(char) * (strlen(line) + 1)) + 64);
+        char sub_line[256];
+        int prev_eo = 0;
+        memset(sub_line, 0, 256);
+        strcpy(line2, line);
+        regmatch_t match_structs;
+        
+        match_found = 0;
+        match_status = regexec(pattern, line2, 1, &match_structs, 0);
+        
+        while (match_status == 0) {
+                
+                memset(sub_line, 0, 256);
+                
+                if (match_found == 0)   
+                        match_found = 1;
+                
+                line2 = insert_highlights(line2, match_structs.rm_so + prev_eo, match_structs.rm_eo + prev_eo);
+                if (match_structs.rm_eo + 11 + prev_eo < strlen(line2))
+                        strcat(sub_line, line2 + match_structs.rm_eo + 11 + prev_eo);
+
+                prev_eo += match_structs.rm_eo + 11;
+                match_status = regexec(pattern, sub_line, 1, &match_structs, REG_NOTBOL);
+        }
+        
+        return line2;
+}
+
+char *insert_highlights (char *line, int start, int end) {
+        
+        char *new_line = (char *) malloc((sizeof(char) * (strlen(line) + 1)) + 10);
+        memset(new_line, 0, ((sizeof(char) * (strlen(line) + 1)) + 10));
+        strncat(new_line, line, start);
+        strcat(new_line, HIGHLIGHT);
+        strncat(new_line, line + start, end - start);
+        strcat(new_line, NORMAL);
+        strncat(new_line, line + end, strlen(line) - end);
+        
+        return new_line;
+}
+
+static void goto_match(int match) {
+        
+        /* This goes to a specific match - all line positions of matches are
+           stored within the match_lines[] array. */
+        if ((match < num_matches) && (match >= 0)) {
+                buffer_line(match_lines[match]);
+                match_pos = match;
+        }
+}
+
+static void search_backwards() {
+        
+        int current_linepos = line_pos; 
+        int i;
+        
+        match_backwards = 1;
+        regex_process();
+                
+        for (i = 0; i < num_matches; i++) {
+                if (match_lines[i] > current_linepos) {
+                        buffer_line(match_lines[i - num_back_match]);
+                        break;
+                }
+        }
+        
+        /* Reset variables */
+        match_backwards = 0;
+        num_back_match = 1;
+        
+}
+#endif
+
+#ifdef CONFIG_FEATURE_LESS_BRACKETS
+
+static char opp_bracket (char bracket) {
+
+        switch (bracket) {
+                case '{': case '[':
+                        return bracket + 2;
+                        break;
+                case '(':
+                        return ')';
+                        break;
+                case '}': case ']':
+                        return bracket - 2;
+                        break;
+                case ')':
+                        return '(';
+                        break;
+                default:
+                        return 0;
+                        break;
+        }
+}
+
+static void match_right_bracket(char bracket) {
+        
+        int bracket_line = -1;
+        int i;
+        
+        if (strchr(flines[line_pos], bracket) == NULL) {
+                clear_line();
+                printf("%s%s%s", HIGHLIGHT, "No bracket in top line", NORMAL);
+        }
+        else {
+                for (i = line_pos + 1; i < num_flines; i++) {
+                        if (strchr(flines[i], opp_bracket(bracket)) != NULL) {
+                                bracket_line = i;
+                                break;
+                        }
+                }
+
+                if (bracket_line == -1) {
+                        clear_line();
+                        printf("%s%s%s", HIGHLIGHT, "No matching bracket found", NORMAL);
+                }
+
+                buffer_line(bracket_line - height + 2);
+                buffer_print();
+        }
+}
+
+static void match_left_bracket (char bracket) {
+        
+        int bracket_line = -1;
+        int i;
+
+        if (strchr(flines[line_pos + height - 2], bracket) == NULL) {
+                clear_line();
+                printf("%s%s%s", HIGHLIGHT, "No bracket in bottom line", NORMAL);
+                printf("%s", flines[line_pos + height]);
+                sleep(4);
+        }
+        else {
+                for (i = line_pos + height - 2; i >= 0; i--) {
+                        if (strchr(flines[i], opp_bracket(bracket)) != NULL) {
+                                bracket_line = i;
+                                break;
+                        }
+                }
+
+                if (bracket_line == -1) {
+                        clear_line();
+                        printf("%s%s%s", HIGHLIGHT, "No matching bracket found", NORMAL);
+                }
+        
+                buffer_line(bracket_line);
+                buffer_print();
+        }
+}
+
+#endif
+
+int less_main(int argc, char **argv) {
+        
+        unsigned long flags;
+        int keypress;
+        
+        flags =  bb_getopt_ulflags(argc, argv, "EMNm~");
+        E_FLAG = (flags & 1);
+        M_FLAG = (flags & 2);
+        N_FLAG = (flags & 4);
+        m_FLAG = (flags & 8);
+        TILDE_FLAG = (flags & 16);
+
+        argc -= optind;
+        argv += optind;
+        files = argv;
+        num_files = argc;
+        
+        if (!num_files) {
+                if (ttyname(STDIN_FILENO) == NULL)
+                        inp_stdin = 1;
+                else {
+                        bb_error_msg("Missing filename");
+                        bb_show_usage();
+                }
+        }
+        
+        strcpy(filename, (inp_stdin) ? "stdin" : files[0]);
+        tty_width_height();
+        data_readlines();
+        buffer_init();
+        buffer_print();
+        
+        while (1) {
+                keypress = tless_getch();
+                keypress_process(keypress);
+        }
+}