view xrogue/maze.c @ 310:827441d05b3e

Advanced Rogue family: fix some potential buffer overflows. Some code for determining the score file location assumed that PATH_MAX would be less than 1024, which cannot be guaranteed. Advanced Rogue 5 and 7, and XRogue, have had the buffers for the file name enlarged. UltraRogue never called the functions, so the code has been deleted instead.
author John "Elwin" Edwards
date Mon, 03 May 2021 19:05:37 -0400
parents 0250220d8cdd
children
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/*
    maze.c  -  functions for dealing with mazes
    
    XRogue: Expeditions into the Dungeons of Doom
    Copyright (C) 1991 Robert Pietkivitch
    All rights reserved.
    
    Based on "Advanced Rogue"
    Copyright (C) 1984, 1985 Michael Morgan, Ken Dalka and AT&T
    All rights reserved.

    See the file LICENSE.TXT for full copyright and licensing information.
*/

#include <stdlib.h>
#include <curses.h>
#include "rogue.h"

struct cell {
        char y_pos;
        char x_pos;
};
struct b_cellscells {
        unsigned char num_pos;  /* number of frontier cells next to you */
        struct cell conn[4];    /* the y,x position of above cell */
} b_cells;

static char     *maze_frontier, *maze_bits;
static int      maze_lines, maze_cols;
static char    *moffset(int y, int x);
static char    *foffset(int y, int x);
static void     rmwall(int newy, int newx, int oldy, int oldx);
static void     draw_maze(void);
static int      findcells(int y, int x);

/*
 * crankout:
 *      Does actual drawing of maze to window
 */

static
void
crankout(void)
{
    reg int x, y;

    for (y = 0; y < lines - 3; y++) {
        move(y + 1, 0);
        for (x = 0; x < cols - 1; x++) {
            if (*moffset(y, x)) {           /* here is a wall */
                if(y==0 || y==lines-4) /* top or bottom line */
                    addch(HORZWALL);
                else if(x==0 || x==cols-2) /* left | right side */
                    addch(VERTWALL);
                else if (y % 2 == 0 && x % 2 == 0) {
                    if(*moffset(y, x-1) || *moffset(y, x+1))
                        addch(HORZWALL);
                    else
                        addch(VERTWALL);
                }
                else if (y % 2 == 0)
                    addch(HORZWALL);
                else
                    addch(VERTWALL);
            }
            else
                addch(FLOOR);
        }
    }
}

/*
 * domaze:
 *      Draw the maze on this level.
 */

void
do_maze(void)
{
        reg int least;
        reg struct room *rp;
        reg struct linked_list *item;
        reg struct object *obj;
        int cnt;
        bool treas;
        coord tp;

        for (rp = rooms; rp < &rooms[MAXROOMS]; rp++) {
                rp->r_flags = ISGONE;           /* kill all rooms */
                rp->r_fires = NULL;             /* no fires */
        }
        rp = &rooms[0];                         /* point to only room */
        rp->r_flags = ISDARK;                   /* mazes always dark */
        rp->r_pos.x = 0;                        /* room fills whole screen */
        rp->r_pos.y = 1;
        rp->r_max.x = cols - 1;
        rp->r_max.y = lines - 3;
        draw_maze();                            /* put maze into window */
        /*
         * add some gold to make it worth looking for 
         */
        item = spec_item(GOLD, 0, 0, 0);
        obj = OBJPTR(item);
        obj->o_count *= (rnd(50) + 50);         /* add in one large hunk */
        attach(lvl_obj, item);
        cnt = 0;
        do {
            rnd_pos(rp, &tp);
        } until (mvinch(tp.y, tp.x) == FLOOR || cnt++ > 2500);
        mvaddch(tp.y, tp.x, GOLD);
        obj->o_pos = tp;
        /*
         * add in some food to make sure he has enough
         */
        item = spec_item(FOOD, 0, 0, 0);
        obj = OBJPTR(item);
        attach(lvl_obj, item);
        do {
            rnd_pos(rp, &tp);
        } until (mvinch(tp.y, tp.x) == FLOOR || cnt++ > 2500);
        mvaddch(tp.y, tp.x, FOOD);
        obj->o_pos = tp;

        /* it doesn't mater if it's a treasure maze or a normal maze,
         * more than enough monsters will be genned. 
         */
        least = rnd(11)+5;
        if (least < 6) {
        least = 7;
        treas = FALSE;
    }
    else treas = TRUE;
        genmonsters(least, treas);

        /* sometimes they're real angry */
        if (rnd(100) < 65) {
            /* protect the good charactors */
            if (player.t_ctype == C_PALADIN ||
                player.t_ctype == C_RANGER  || player.t_ctype == C_MONK) {
                aggravate(TRUE, FALSE);
            }
            else {
                aggravate(TRUE, TRUE);
            }
        }
}

/*
 * draw_maze:
 *      Generate and draw the maze on the screen
 */

static
void
draw_maze(void)
{
        reg int i, j, more;
        reg char *ptr;

        maze_lines = (lines - 3) / 2;
        maze_cols = (cols - 1) / 2;
        maze_bits = ALLOC((lines - 3) * (cols - 1));
        maze_frontier = ALLOC(maze_lines * maze_cols);
        ptr = maze_frontier;
        while (ptr < (maze_frontier + (maze_lines * maze_cols)))
                *ptr++ = TRUE;
        for (i = 0; i < lines - 3; i++) {
                for (j = 0; j < cols - 1; j++) {
                        if (i % 2 == 1 && j % 2 == 1)
                                *moffset(i, j) = FALSE;         /* floor */
                        else
                                *moffset(i, j) = TRUE;          /* wall */
                }
        }
        for (i = 0; i < maze_lines; i++) {
                for (j = 0; j < maze_cols; j++) {
                        do
                                more = findcells(i,j);
                        while(more != 0);
                }
        }
        crankout();
        FREE(maze_frontier);
        FREE(maze_bits);
}

/*
 * findcells:
 *      Figure out cells to open up 
 */

static int
findcells(int y, int x)
{
        reg int rtpos, i;

        *foffset(y, x) = FALSE;
        b_cells.num_pos = 0;
        if (y < maze_lines - 1) {                               /* look below */
                if (*foffset(y + 1, x)) {
                        b_cells.conn[b_cells.num_pos].y_pos = y + 1;
                        b_cells.conn[b_cells.num_pos].x_pos = x;
                        b_cells.num_pos += 1;
                }
        }
        if (y > 0) {                                    /* look above */
                if (*foffset(y - 1, x)) {
                        b_cells.conn[b_cells.num_pos].y_pos = y - 1;
                        b_cells.conn[b_cells.num_pos].x_pos = x;
                        b_cells.num_pos += 1;

                }
        }
        if (x < maze_cols - 1) {                                /* look right */
                if (*foffset(y, x + 1)) {
                        b_cells.conn[b_cells.num_pos].y_pos = y;
                        b_cells.conn[b_cells.num_pos].x_pos = x + 1;
                        b_cells.num_pos += 1;
                }
        }
        if (x > 0) {                                    /* look left */
                if (*foffset(y, x - 1)) {
                        b_cells.conn[b_cells.num_pos].y_pos = y;
                        b_cells.conn[b_cells.num_pos].x_pos = x - 1;
                        b_cells.num_pos += 1;

                }
        }
        if (b_cells.num_pos == 0)               /* no neighbors available */
                return 0;
        else {
                i = rnd(b_cells.num_pos);
                rtpos = b_cells.num_pos - 1;
                rmwall(b_cells.conn[i].y_pos, b_cells.conn[i].x_pos, y, x);
                return rtpos;
        }
}

/*
 * foffset:
 *      Calculate memory address for frontier
 */

static char *
foffset(int y, int x)
{

        return (maze_frontier + (y * maze_cols) + x);
}


/*
 * Maze_view:
 *      Returns true if the player can see the specified location within
 *      the confines of a maze (within one column or row)
 */

bool
maze_view(int y, int x)
{
    register int start, goal, delta, ycheck = 0, xcheck = 0, absy, absx, see_radius;
    register bool row;

    /* Get the absolute value of y and x differences */
    absy = hero.y - y;
    absx = hero.x - x;
    if (absy < 0) absy = -absy;
    if (absx < 0) absx = -absx;

    /* If we are standing in a wall, we can see a bit more */
    switch (winat(hero.y, hero.x)) {
        case VERTWALL:
        case HORZWALL:
        case WALL:
        case SECRETDOOR:
        case DOOR:
            see_radius = 2;
        otherwise:
            see_radius = 1;
    }

    /* Must be within one or two rows or columns */
    if (absy > see_radius && absx > see_radius) return(FALSE);

    if (absx > see_radius) {            /* Go along row */
        start = hero.x;
        goal = x;
        ycheck = hero.y;
        row = TRUE;
    }
    else {                      /* Go along column */
        start = hero.y;
        goal = y;
        xcheck = hero.x;
        row = FALSE;
    }

    if (start <= goal) delta = 1;
    else delta = -1;

    /* Start one past where we are standing */
    if (start != goal) start += delta;

    /* If we are in a wall, we want to look in the area outside the wall */
    if (see_radius > 1) {
        if (row) {
            /* See if above us it okay first */
            switch (winat(ycheck, start)) {
                case VERTWALL:
                case HORZWALL:
                case WALL:
                case DOOR:
                case SECRETDOOR:
                    /* No good, try one up */
                    if (y > hero.y) ycheck++;
                    else ycheck--;
                otherwise:
                    see_radius = 1;     /* Just look straight over the row */
            }
        }
        else {
            /* See if above us it okay first */
            switch (winat(start, xcheck)) {
                case VERTWALL:
                case HORZWALL:
                case WALL:
                case DOOR:
                case SECRETDOOR:
                    /* No good, try one over */
                    if (x > hero.x) xcheck++;
                    else xcheck--;
                otherwise:
                    see_radius = 1;     /* Just look straight up the column */
            }
        }
    }

    /* Check boundary again */
    if (absy > see_radius && absx > see_radius) return(FALSE);

    while (start != goal) {
        if (row) xcheck = start;
        else     ycheck = start;

        if (xcheck < 0 || ycheck < 0)
            return FALSE;
        switch (winat(ycheck, xcheck)) {
            case VERTWALL:
            case HORZWALL:
            case WALL:
            case DOOR:
            case SECRETDOOR:
                return(FALSE);
        }
        start += delta;
    }
    return(TRUE);
}


/*
 * moffset:
 *      Calculate memory address for bits
 */

static char *
moffset(int y, int x)
{
    return (maze_bits + (y * (cols - 1)) + x);
}

/*
 * rmwall:
 *      Removes appropriate walls from the maze
 */
static
void
rmwall(int newy, int newx, int oldy, int oldx)
{
        reg int xdif,ydif;
        
        xdif = newx - oldx;
        ydif = newy - oldy;

        *moffset((oldy * 2) + ydif + 1, (oldx * 2) + xdif + 1) = FALSE;
        findcells(newy, newx);
}