TweetFollow Us on Twitter

Puzzles as Resources
Volume Number:2
Issue Number:3
Column Tag:Developer's Forum

Puzzles as Resources in Aztec C

By David Levner, Sabaki Corp., Product: Polyomino Puzzles

Polyomino Puzzle Resources


Sam Loyd created polyomino puzzles 80 years ago. He didn't have a Macintosh, so he made his puzzles out of cardboard. I am lucky to own a Mac, so I wrote the game MacPoly to draw polyominoes on the screen.

MacPoly stores polyomino puzzles as resources, in a format described in this article. A method for creating these resources is presented, enabling you to add your own puzzles to MacPoly. The method may also be used to create other custom resources.


The word 'polyomino' is a generalization of 'domino'. A domino is made of two squares, and a polyomino many squares. Here are some polyominoes:

Figure 1

An easy puzzle is shown below. The object is to cover the white square (the solution shape) with the four gray pieces. Most polyomino puzzles are much more difficult.

6 x 6 Square

Figure 2

Puzzle Source Files

The first step in creating a puzzle is to enter a puzzle source file. For example, this is the source file I used to generate figure 2:

6 x 6 Square Congratulations! Puzzle by David Levner.


Figure 3

Use a mono-spaced font, like Monaco to make the columns line up, and save the file as text only. The first line of the file contains the puzzle name, followed by a congratulatory message that is displayed when the puzzle is solved. Then begins the puzzle grid.

The grid contains letters that stand for the squares of polyominoes. Lower case letters represent squares that are outside the solution shape, and upper case letters, except 'S', are squares covering the solution (none are shown in this example). Non-alphabetic characters (the dots) are empty spaces that are not part of the solution , and the letter 'S' denotes the squares of the solution that are not covered by any polyominoes.

Solution Source Files

The solution to a puzzle is represented by a very similar source file. The only difference is that there is no congratulatory message.

6 x 6 Square Solution


Figure 4

Puzzle and Solution Resources

A program could read these source files directly, but that would be less efficient than reading resources on the Mac. At the end of this article, a program is listed to convert puzzle and solution source files into resources.

MacPoly's puzzles are divided into 9 categories. Puzzle resources have type SBPn, where n is a digit from 1 to 9, and solutions have type SBSn.

Resource Type Puzzle Type

SBP1 Easy puzzles

SBP2 Rectangles

SBP3 Almost Rectangles

SBP4 Parallelograms

SBP5 Chess Boards

SBP6 Polyominoes

SBP7 Chess Pieces

SBP8 Objects

SBP9 Impossible Puzzles

Figure 5

The puzzle resource for 6 x 6 Square looks like this.

Congratulations! Puzzle by David Levner.


Figure 6

The first line of the puzzle source file becomes the resource name. The second copy of the puzzle grid reserves space to store an arrangement of the pieces saved with MacPoly's save command.

Following the second grid are four nine digit numbers, representing (1) the time spent to arrive at the saved position, in seconds, (2) the number of operations performed to arrive at the saved position (MacPoly allows you to select a piece, drag it, flip it, and spin it), (3) the record time to solve the puzzle, in seconds, and (4) the record (fewest) number of operations to solve a puzzle. Initially, these numbers are set to 0, 0, 999999999, and 999999999. At the end of the resource is a binary zero.

A solution resources differs in several ways: there is no congratulations message or timing information, and only one puzzle grid.

Converting Source Files To Resources

I wrote a C program, called ftor, to convert puzzle source files to resources. Ftor is designed to run under a shell program; it cannot be run from the Macintosh desktop. If you try to recreate ftor, you should run it from the shell supplied with your C compiler.

Most shell programs are modeled on the Bourne shell from the Unix operating system. To use a shell, you type a command, which is interpreted as a program name followed by an argument list. All the C compilers I have seen for the Mac include a shell user interface. On the Amiga, Commodore supplies a shell called the Command Line Interface.

I have listed below some dialogs with the shell. The '$' is a prompt character, signifying that the shell is ready to accept a command. I typed the characters following the '$' to run the program ftor; the line below contains the program's output. In this case, I ran ftor without any arguments to remind me what arguments it expects.

 $ ftor
 usage: ftor TYPE outfile infile1 [infile2 ...]

Ftor's first argument is the four letter type of the resource(s) being created, followed by the output file, and one or more puzzle source files. Each source file is converted to a resource and stored in the output file.

 $ ftor SBP1 Puzzles epz

Assuming that the puzzle source file of figure 3 is named epz, the command above creates a resource called "6 x 6 Square" in the file Puzzles. The Puzzles file must already exist and contain at least one resource.

Ftor Program Source

I used Aztec C to compile and link ftor with the following two commands:

 $ cc ftor.c -o ftor.o
 $ ln -o ftor ftor.o -lc


This article demonstrates a method for creating custom resources from ascii source files. Owners of MacPoly can create and enter their own puzzles. Puzzles and solutions should be entered in pairs; otherwise the Solve feature of MacPoly will not work properly.

Custom resources are both bad and good: few toolbox functions can manipulate them, but they do exactly what you want. You must write your own code to deal with them, but porting the code to other computers will be easier.

/* The program ftor converts a puzzle source file into a  */
/* resource. Developed with Aztec C version 1.03.  */
/* Copyright Sabaki Corp.,1985, for MacTutor.  */
/* Note that this is not a stand alone application, but */
/* requires the Aztec C system to execute for the */
/* default Mac user interface. */

#include "stdio.h"       /* contains definition of NULL (0L) */
#include "ctype.h"       /* contains definition of isdigit */
#include "quickdraw.h"   /* Quickdraw */
#include "memory.h"      /* Memory manager */
#include "resource.h"    /* Resource manager */


extern int errno;         /* error number variable */


static long long_type;    /* resource type */

static char flag_puzzle;  /* 1 for puzzles, 0 for solutions */


main(argc, argv) /* Entry point. */

int argc;         /* number of arguments */
char *argv[];    /* argument vector, an array of strings */
 int a;           /* argument counter */
 static char usage_msg[] =
 "usage: ftor TYPE outFile inFile1 [inFile2 ...]\n";
 long c4tol();   /* converts four bytes into a long */
 char *ctop(),   /* converts a C string to a PASCAL string */
      *ptoc();   /* converts a PASCAL string to a C string */

 if  (argc < 4)
    { printf(usage_msg); exit(1); }

 long_type = c4tol(argv[1][0], argv[1][1], argv[1][2], argv[1][3]);
 flag_puzzle = (argv[1][2] == 'P');

 close_application_resource_file();   /* For safety's sake. */

 if  (OpenResFile(ctop(argv[2])) < 0) /* Open the output file. */
     printf("File %s open error %d\n", ptoc(argv[2]), ResError());
    }   /* then */

 /* For each input file, add a resource to the output file. */
 for (a = 3; a < argc; a = a + 1)

}  /* main() */


static add_resource(filename)
/* Convert one input file to a resource in the output file. */

char *filename;         /* name of the input file */
 int data_size,         /* length of the text in the source file */
     header_size,       /* length of text before the puzzle grid */
     resource_size, /* length of the resource being created */
     title_size;        /* length of the resource name */
 char *file_data,     /* text read from the source file */
      title[80];      /* resource name */
 Handle res_handle;   /* handle to resource being created */
 Ptr ptr;               /* pointer to the resource being created */

 /* Read the input file.  Note that if the second parameter  */
 /* passed to read_file() points to NULL, then read_file()  */
 /* allocates a block of storage big enough to hold the  */
 /*  input file. */

 file_data = NULL;
 if  (read_file(filename, &file_data) < 0)
    { printf("File %s error %d.\n", filename, errno); exit(1); }

 for (title_size = 0;     /* Determine the size of the title. */
      file_data[title_size] > '\r';
      title_size = title_size + 1)

 /* Copy title to a C string. */
 strncpy(title, file_data, title_size);
 title[title_size] = 0;

 /* Let the length of the title include the \r character. */
 title_size = title_size + 1;

 /* If a resource by this name already exists, remove it. */
 res_handle = GetNamedResource(long_type, ctop(title));
 if  (res_handle != NULL)

 /* Determine the size of the header, the grid, and the */
/*  resource. The header includes the title and the  */
/*  congratulations message. */

 header_size = title_size;
 while  (file_data[header_size] > '\r')
     header_size = header_size + 1;
 header_size = header_size + 1;

 data_size = strlen(file_data);
 resource_size = data_size - title_size + 1;

 /* If it's a puzzle, allow room for a 2nd grid and timing info. */
 if  ( flag_puzzle )
   resource_size = resource_size + data_size - header_size + 40;

 /* Get a new handle for the resource. */
 res_handle = NewHandle((long) resource_size);
 if  (res_handle == NULL)
    { printf("Memory error %d\n", MemError()); exit(1); }

 HLock(res_handle);  /* Make sure  resource doesn't run off. */
 ptr = *res_handle;

 /* Move the header and the puzzle into the resource. */
 strncpy(ptr, &file_data[title_size], data_size - title_size);
 /* Puzzles include a second puzzle grid,  blank timing info. */
 ptr = ptr + data_size - title_size;
 if  ( flag_puzzle )
     strncpy(ptr, &file_data[header_size],
             data_size - header_size);
     ptr = ptr + data_size - header_size;
     strcpy(ptr, "000000000\r000000000\r999999999\r999999999\r");
    } /* then */
   else  ptr[0] = 0;

 /* Add the resource to the output file. */
 AddResource(res_handle, long_type, UniqueID(long_type), title);

 HUnlock(res_handle);   /* Unlock the resource. */
 free(file_data);      /* Free memory allocated by read_file(). */
}  /* static add_resource() */


long c4tol(c0, c1, c2, c3)
/* Returns a long constructed from the four bytes. */

unsigned char c0, c1, c2, c3;
 return((c0 << 24L) + (c1 << 16L) + (c2 << 8L) + c3);
} /* long c4tol() */


char *ctop(string)
/* Converts a C string to a PASCAL string, which is returned. */

char *string;
 int length;
 char *pstring;

 length = strlen(string);
 for (pstring = &string[length];
      pstring != string;
      pstring = pstring - 1)
     *pstring = *(pstring - 1);
 *string = length;
}  /* char *ctop */

char *ptoc(string)
/* Converts a PASCAL string to a C string, which is returned. */

char *string;
 int i,

 length = *string;
 for (i = 1; i <= length; i = i + 1)
     string[i - 1] = string[i];
 string[length] = 0;
}  /* char *ptoc */

read_file(file_name, data)
/* Reads the data fork of a file. */

char *file_name,  /* name of the file to be read */
     **data;       /* pointer to where the file data should go */
 int fd,           /* file descriptor */
     size;         /* size of the file in bytes */
 extern long lseek();
 extern char *malloc();

 fd = open(file_name, 0);
 if  (fd < 0)
  /* determine the size of the file */
 size = (int) lseek(fd, 0L, 2);
 lseek(fd, 0L, 0);

 if  (*data == NULL)
   *data = malloc(1 + size);  /* leave room for a trailing null */

 if  (*data == NULL)
    { close(fd); return(-1); }  /* malloc failed */

 if  (read(fd, *data, size) != size)
    { close(fd); return(-1); }  /* read failed */

 (*data)[size] = 0;             /* add a trailing null */
}  /* read_file() */


/* Close the application resource file. */

 DetachResource( GetResource('CODE', 1) );
 CloseResFile( CurResFile() );
}             /* close_application_resource_file() */

Community Search:
MacTech Search:

Software Updates via MacUpdate

NTFS 14.3.318 - $19.95
This latest version supports the new macOS 10.12 Sierra! NTFS breaks down the barriers between Windows and OS X. Paragon NTFS effectively solves the communication problems between the Mac system and... Read more
iFFmpeg 6.2.2 - Convert multimedia files...
iFFmpeg is a comprehensive media tool to convert movie, audio and media files between formats. The FFmpeg command line instructions can be very hard to master/understand, so iFFmpeg does all the hard... Read more
ForeverSave 2.1.6 - Universal auto-save...
ForeverSave auto-saves all documents you're working on while simultaneously doing backup versioning in the background. Lost data can be quickly restored at any time. Define your preferred time... Read more
BetterTouchTool 1.961 - Customize Multi-...
BetterTouchTool adds many new, fully customizable gestures to the Magic Mouse, Multi-Touch MacBook trackpad, and Magic Trackpad. These gestures are customizable: Magic Mouse: Pinch in / out (zoom... Read more
EtreCheck 3.1.4 - For troubleshooting yo...
EtreCheck is an app that displays the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to... Read more
Together 3.7 - Store and organize all of...
Together helps you organize your Mac, giving you the ability to store, edit and preview your files in a single clean, uncluttered interface. Features Smart storage. With simple drag-and-drop... Read more
Together 3.7 - Store and organize all of...
Together helps you organize your Mac, giving you the ability to store, edit and preview your files in a single clean, uncluttered interface. Features Smart storage. With simple drag-and-drop... Read more
EtreCheck 3.1.4 - For troubleshooting yo...
EtreCheck is an app that displays the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to... Read more
Postbox 5.0.9 - Powerful and flexible em...
Postbox is a new email application that helps you organize your work life and get stuff done. It has all the elegance and simplicity of Apple Mail, but with more power and flexibility to manage even... Read more
DiskCatalogMaker 6.5.16 - Catalog your d...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast. Finder-like intuitive look and feel. Super-fast search algorithm. Can compress catalog data... Read more

Latest Forum Discussions

See All

Enneas Saga lets you lead your own demon...
Defend the land of Enneas Continent from the forces of evil in the new fantasy MMORPG from Lyto Mobi: Enneas Saga. Can’t wait? No problem. It’s available to download now on Android devices. | Read more »
Great zombie games in the spirit of Dead...
Dead Rising 4 arrives tomorrow, giving enthusiasts a fresh chance to take selfies with zombies and get up to other ridiculous end-of-the-world shenanigans. To really get into the spirit of things, we've gone and gathered the best zombie games that... | Read more »
Amateur Surgeon 4 Guide: Advanced tips a...
Amateur Surgeon 4 is still tackling the competition at the top of the App Store charts, so if you haven't tried it out yet, you should probably do that right away. If you've been at it for a while, though, perhaps you're ready to start expanding... | Read more »
Amateur Surgeon 4 Guide: Become the worl...
It's time to wield your trusty pizza cutter again, as Amateur Surgeon has returned with a whole fresh set of challenges (and some old, familiar ones, too). Starting anew isn't easy, especially when all you have at your disposal is a lighter, the... | Read more »
Le Parker: Sous Chef Extraordinaire (Ga...
Le Parker: Sous Chef Extraordinaire 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »
Telltale Games really is working on a Gu...
Telltale Games' next episodic adventure is indeed Guardians of the Galaxy. A document tied to the voice actors strike suggested that the project was in the work, but now we have direct confirmation following an announcement at the Game Awards that... | Read more »
Amateur Surgeon returns to iOS and Andro...
Amateur Surgeon and its two sequels disappeared from the App Store some time and it was sad days for all. But now, just in time for the holidays, the Adult Swim favorite makes its joyous return in the shape of Amateur Surgeon 4, a remake with... | Read more »
The best board games on mobile
Sometimes you need to ditch all of the high speed, high action games in favor of something a little more traditional. If you don't feel like parting ways from your mobile device, though, there are still plenty of ways to get that old-school fix.... | Read more »
The best Facebook Messenger Instant Game...
Facebook's new Instant Games is now here, meaning you can play games with your friends directly via Facebook. It's a fun new way to connect with friends, of course, but it's also proving to be a solid gaming experience in its own right, with a... | Read more »
You can now play game's on Facebook...
Facebook launched its new Instant Games platform in an exciting new attempt to engage its user base. As a result, you can now play a number of different games directly through Facebook Messenger. All of these games run with HTML5, meaning you play... | Read more »

Price Scanner via

Slate Tablet Market Share to Fall Below 75% i...
After two years of decline, the tablet market is showing signs of new life as productivity trumps entertainment, and tablets become cost-effective computing devices for both entertainment and... Read more
Yostand Launches Indigogo campaign for iStand...
China-based startup Yostand (meaning ‘your stand’), has announced the launch of its Indigogo campaign for their newly awaited iStand7. This product is a one of a kind iPhone battery case that offers... Read more
Green App – Budget Forecasting Now Available...
Indianapolis, Indiana based CoopToons has announced the release of Green – Budget Forecasting 1.5, an update to their personal budgeting app developed exclusively for iOS devices. Green aims to be a... Read more
New 2016 13-inch 2.0GHz MacBook Pros in stock... has the non-Touch Bar 13″ MacBook Pros in stock today for $150 off MSRP. Shipping is free: - 13″ 2.0GHz MacBook Pro Space Gray (MLL42LL/A): $1349.99 $150 off MSRP - 13″ 2.0GHz MacBook... Read more
15-inch 2.6GHz Silver Touch Bar MacBook Pro o...
Adorama has the new 2016 15″ 2.6GHz Silver Touch Bar MacBook Pro (MLW72LL/A) in stock and available for $2349 including free shipping. Adorama charges sales tax in NY & NJ only. Their price is $... Read more
13-inch MacBook Airs on sale for up to $180 o... has 13″ MacBook Airs on sale for up to $180 off MSRP including free shipping: - 13″ 1.6GHz/128GB MacBook Air (MMGF2LL/A): $869.99 $130 off MSRP - 13″ 1.6GHz/256GB MacBook Air (sku... Read more
13-inch 2.5GHz MacBook Pro (Apple refurbished...
Apple has Certified Refurbished 13″ 2.5GHz MacBook Pros (MD101LL/A) available for $829, or $270 off original MSRP. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.5GHz MacBook... Read more
Monday roundup of Holiday Mac sales: Up to $3...
Take up to $300 off MSRP on the price of a new Apple Mac at B&H Photo today as part of their Holiday sale. Shipping is free, and B&H charges NY sales tax only. Touch Bar MacBook Pros are in... Read more
12-inch WiFi Apple iPad Pros on sale for up t...
B&H Photo has 12″ WiFi Apple iPad Pros on sale for up to $50 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 12″ Space Gray 32GB WiFi iPad Pro: $749 $50 off MSRP... Read more
9-inch Apple WiFi iPad Pros on sale for $20-$...
B&H Photo has 9.7″ Apple WiFi iPad Pros on sale for $20-$50 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 9″ Space Gray 256GB WiFi iPad Pro: $779.95 $20 off MSRP... Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Lead *Apple* Solutions Consultant - Apple (...
# Lead Apple Solutions Consultant Job Number: 53586123 Pittsburgh, Pennsylvania, United States Posted: Nov. 28, 2016 Weekly Hours: 40.00 **Job Summary** The Lead ASC Read more
*Apple* Retail - Multiple Positions- Plano,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions- Kansas...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions- Chicago...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.