Fast maze generator

nodemaze.c

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>

#define VERSION "v0.5"

typedef struct
{
	int x, y;
	void *parent;
	char c;
	int dirs;
} Node;


struct
{
	Node *nodes;
	int width, height;
} map;

int initMap( )
{
	int i, j;
	Node *n;
	
	if ( ( map.nodes = calloc( map.width * map.height, sizeof( Node ) ) ) == NULL ) return 1;
		
	for ( i = 0; i < map.width; i++ )
	{
		for ( j = 0; j < map.height; j++ )
		{
			n = &map.nodes[i + j * map.width];
			if ( i * j % 2 ) 
			{
				n->x = i;
				n->y = j;
				n->dirs = 15;
				n->c = ' '; 
			}
			else 
			{
				n->c = '#'; 
			}
		}
	}
	return 0;
}

Node *linkNode( Node *n )
{
	int x, y;
	int dir;
	Node *dest;
	
	if ( n == NULL ) return NULL;
	
	n->c = ' ';
	
	
	while ( n->dirs )
	{
		dir = ( 1 << ( rand( ) % 4 ) );
		if ( ~n->dirs & dir ) continue;
		n->dirs &= ~dir;
		
		switch ( dir )
		{
			case 1:
				if ( n->x + 2 < map.width )
				{
					x = n->x + 2;
					y = n->y;
				}
				else continue;
				break;
				
			case 2:
				if ( n->y + 2 < map.height )
				{
					x = n->x;
					y = n->y + 2;
				}
				else continue;
				break;
				
			case 4:
				if ( n->x - 2 >= 0 )
				{
					x = n->x - 2;
					y = n->y;
				}
				else continue;
				break;
				
			case 8:
				if ( n->y - 2 >= 0 )
				{
					x = n->x;
					y = n->y - 2;
				}
				else continue;
				break;
		}
		dest = map.nodes + x + y * map.width;
		
		if ( dest->c == ' ' )
		{
			if ( dest->parent != NULL ) continue;
			dest->parent = n;
			map.nodes[n->x + ( x - n->x ) / 2 + ( n->y + ( y - n->y ) / 2 ) * map.width].c = ' ';
			return dest;
		}
	}
	return n->parent;
}

void mapDraw( )
{
	int i, j;

	for ( i = 0; i < map.height; i++ )
	{
		for ( j = 0; j < map.width; j++ )
		{
			printf( "%c", map.nodes[j + i * map.width].c );
		}
		printf( "\n" );
	}
}

int main( int argc, char **argv )
{
	int i, badarg;
	long seed;
	Node *start, *last;

	seed = time( NULL );
	
	map.width = 41;
	map.height = 21;	
	
	for ( i = 1; i < argc; i++ )
	{
		badarg = 1;
		
		if ( !strcmp( argv[i], "-h" ) || !strcmp( argv[i], "--help" ) )
		{
			fprintf( stderr, "%s - pretty fast DFS maze generator " VERSION "\n", argv[0] );
			fprintf( stderr, "\t-h - display this help message\n" );
			fprintf( stderr, "\t-x <width> - maze width\n" );
			fprintf( stderr, "\t-y <height> - maze height\n" );
			fprintf( stderr, "\t-s <seed> - random generator seed\n" );
			badarg = 0;
			exit( 0 );
		}
		
		if ( !strcmp( argv[i], "-x" ) )
			if ( ++i >= argc || ( badarg = 0, !sscanf( argv[i], "%d", &map.width ) ) ) 
				fprintf( stderr, "%s: bad value for '%s'\n", argv[0], argv[i - 1] ), exit( 1 );

		if ( !strcmp( argv[i], "-y" ) )
			if ( ++i >= argc || ( badarg = 0, !sscanf( argv[i], "%d", &map.height ) ) ) 
				fprintf( stderr, "%s: bad value for '%s'\n", argv[0], argv[i - 1] ), exit( 1 );
				
		if ( !strcmp( argv[i], "-s" ) )
			if ( ++i >= argc || ( badarg = 0, !sscanf( argv[i], "%ld", &seed ) ) ) 
				fprintf( stderr, "%s: bad value for '%s'\n", argv[0], argv[i - 1] ), exit( 1 );
			
		if ( badarg )
		{
			fprintf( stderr, "%s: unrecognized option '%s'\n", argv[0], argv[i] );
			exit( 1 );
		}
	}
	
	if ( !( map.width % 2 ) || !( map.height % 2 ) )
	{
		fprintf( stderr, "%s: dimensions must be odd!\n", argv[0] );
		exit( 1 );
	}

	if ( initMap( ) )
	{
		fprintf( stderr, "%s: out of memory!\n", argv[0] );
		exit( 1 );
	}
	
	start = &map.nodes[1 + 1 * map.width];
	start->parent = start;
	last = start;
	while ( ( last = linkNode( last ) ) != start );
	mapDraw( );
}