TweetFollow Us on Twitter

Jul 95 Challenge
Volume Number:11
Issue Number:7
Column Tag:Programmer’s Challenge

Programmer’s Challenge

By Bob Boonstra and Mike Scanlin

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

Goodbye Mike

[Most of you are well aware of the excellence Mike Scanlin has brought to the magazine since the summer of 1992. Back then, Mike suggest to me that we start a programming puzzle to encourage programmers to write efficient code. Like many quality programmers, Mike was concerned that with the advent of faster machines, programmers were becoming lax in their ways.

The MacTech Programmer’s Challenge grew out of these conversations into the industry icon it is today. We’ve been stopped at trade shows and user group meetings by folks who are proudly wearing their MacTech Programmer’s Challenge Winner t-shirts. They should be proud - it is an accomplishment. We’re thrilled that the Challenge has had this impact on the developer community.

As publisher, working with Mike has been an absolute joy. After almost three years of running the challenge and devising puzzles, Mike is moving on. While his career has spanned such greats like WriteNow, PhotoFlash, and today General Magic, Mike cares about you all, the Challenge, and the magazine. So together, we’ve hand-picked someone we feel is the most qualified successor - Bob Boonstra.

Some of you might recognize Bob as a regular participant (and all-time winner) in past Challenges. Bob’s passion for efficiency dates back to his self-taught introduction to programming, starting in hex, then assembly language, and only later graduating to high level languages. He is a member of the Value-Added NewsWatcher team, adding a few features to John Norstad’s excellent newsreader. When he isn’t writing or reverse engineering code (or working at an unspecified day job), Bob spends time introducing his 8- and 10-year old children to the joys of hiking in the White Mountains, and to the world of Macintosh, but usually not both at the same time.

We wish Mike the best of luck and we welcome Bob with open arms. We hope you do as well. Ed./Pub. -nst]

Sprite Blitz

Most of you are probably familiar with the great shareware arcade games that are available for the Mac. This month you will be writing a key element of an arcade game - the code that moves graphic elements (“sprites”) across a background. There are a number of libraries that do much of this work for the aspiring game writer, but I want to see how fast you can do it, and hopefully we will all benefit from the techniques in the winning code.

The prototypes of the code you must write are as follows:

void StartGame(
/* pointer to CWindow */
 CWindowPtr theWind
);

short /*theSpriteID*/ AddSprite(
/* pointer to ‘cicn' */
 CIconPtr theSprite,
/* initial sprite location */
 Point startLoc 
); /* returns sprite ID to be used in MoveSprite, DeleteSprite */

void DeleteSprite(
/* ID of sprite to delete */
 short theSpriteID 
);

void MoveSprite(
/* ID of sprite to move */
 short theSpriteID,
/* amount to move sprite 
    NOTE: offset, not new location */
 Point amountToMove
);

void UpdateScreen(void);  

The problem works like this. Your routine StartGame will be called first and will be provided with a pointer to a color window. The window will be preset to a background that must be preserved, except for portions that are obscured by sprites. StartGame will not be timed, so you can do whatever initialization you need to do, like allocating an offscreen pixmap and initializing it to the contents of the window. Your routines AddSprite, DeleteSprite, and MoveSprite will then be called repeatedly to add, delete, and move sprites. Your routine UpdateScreen will also be called repeatedly, at which time you must redraw all sprites at their current locations and restore the background at their old locations.

Sprites will be provided to AddSprite as ‘cicn’ data structures, described in IM V-80 or NIM Imaging 4-105. Even though a ‘cicn’ can have an arbitrary shape, the sprites your code sees will have widths that are 1, 2, 4, 8, 16, or 32 pixels, to simplify things, but any height up to 32 pixels. A ‘cicn’ also has an associated mask, and you need to remember to show the correct part of the background through any holes in the mask. One way to draw the sprites, of course, is with the toolbox routine PlotCIcon, but you might find a better way

To simplify the problem, you can rely on (**theWind->portPixMap).bounds being longword aligned on a single monitor that is in 256 color mode, and on the pixelSize being 8 bits. The background will not change over time (i.e., you don’t have to handle a scrolling background). You can assume that there will be no more than 200 active sprites, and you can assume a sprite will not move more than 8 pixels horizontally or more than 8 pixels vertically in any given MoveSprite call. The color table of each sprite ‘cicn’ will be the same as that in the window PixMap. In a real game, you would probably do some collision detection on sprites, but our sprites will pass thru one another oblivious to the collision. In the event sprites overlap, you should draw them in the order that they were created by AddSprite (so that the sprite created last would be drawn over other sprites). You will need to do bounds checking of the sprite location against the window, because our sprites may move partially or completely out of the window.

This problem would be appropriate for an assembly language Challenge, but we’ll see how well you can do in straight C. Entries with obviously jerky visual effects will be considered less “correct” than those with smooth visual effects. I’ll select the winner from the correct entries based on how fast the code runs on a 68040 using the THINK C compiler, but - deadline permitting - I’ll also measure native execution time on a PowerPC. Now start blitting those sprites!

Two Months Ago Winner

Congratulations to Raffi Kasparian (Baltimore, MD) for having the fastest and smallest entry in the Hyphenation Challenge. Excellent job! This is Raffi’s second 1st place showing (he also won the Tile Windows Challenge in July 1993).

Here are the times and code sizes for the entries that worked. Numbers in parens after a person’s name indicate that person’s cumulative point total for all previous Programmer Challenges, not including this one:

Name time code

Raffi Kasparian (22) 99 348

Peter McA’Nulty 111 616

Ronald Nepsund (40) 121 402

Björn Davidsson 137 788

Robert Noll (20) 139 542

Bill Wade 165 462

Ernst Munter (60) 165 1036

Brian Moffat 171 1240

Dave Darrah (31) 220 666

Robert Westlund 293 476

Rick Genter 315 4276

D.H. 16928 978

E.O. 36536 764

M.D. 39727 3562

Raffi made the observation that there was a simpler rule that satisfied the given rules for hyphenating. This was not my intention (I try hard not to give trick Challenges) but I congratulate Raffi on finding this alternative. His main rule (given in his comments) is “Working forward from the beginning of the word until the last vowel is reached (not counting final e, es or ed), hyphenate every vowel-consonant pair unless the vowel is followed by a double consonant. In this case, hyphenate between the double consonant. This method meets the hyphenation requirements without having to deal directly with all the letter combination rules.” Needless to say, this simplifies the code quite a bit.

Many people wrote to me and asked about the “pairs of unsplitable pairs” rule. In the Challenge, I said, “No break is made between any two of the following letter combinations: sh, gh, p, ch, th, wh, gr, pr, cr, tr, wr, br, fr, dr, vowel-r, vowel-n, or om.” Then I proceeded to give a confusing example that wouldn’t have been hyphenated anyway because of other rules. Sorry. Here’s a better example: This hyphen in ‘chin-chilla’ is illegal because ‘in’ and ‘ch’ are both on the list of pairs that can’t have a hyphen between them. Some people misinterpreted the rule to mean “don’t hyphenate any of these pairs”. My apologies. Once again, I urge you to send e-mail to one of the Programmer Challenge addresses if there is any doubt about the stated rules.

As I said last month, I am turning this column over to Bob Boonstra. This month’s Sprite Blitz Challenge is Bob’s second puzzle. Next month is Bob’s first month at owning both halves of this column (a new puzzle and a previous answer). Please direct any future ideas, questions, or comments regarding this column to Bob at any of the Programmer Challenge addresses given in the front of the magazine.

So long and keep on optimizing!

Mike Scanlin
scanlin@genmagic.com

Top 20 Contestants of All Time

Here are the Top 20 Contestants for the 35 Programmer’s Challenges to date. The numbers below include points awarded for this months’ entrants. (Note: ties are listed alphabetically by last name - there are 24 people listed this month because 6 people have 20 points each.)

1. Boonstra, Bob 176

2. Karsh, Bill 71

3. Stenger, Allen 65

4. Larsson, Gustav 60

5. Munter, Ernst 60

6. Riha, Stepan 51

7. Goebel, James 49

8. Nepsund, Ronald 47

9. Cutts, Kevin 46

10. Mallett, Jeff 44

11. Kasparian, Raffi 42

12. Vineyard, Jeremy 40

13. Darrah, Dave 31

14. Landry, Larry 29

15. Elwertowski, Tom 24

16. Gregg, Xan 24

17. Lee, Johnny 22

18. Noll, Robert 22

19. Anderson, Troy 20

20. Burgoyne, Nick 20

21. Galway, Will 20

22. Israelson, Steve 20

23. Landweber, Greg 20

24. Pinkerton, Tom 20

There are three ways to earn points: (1) by scoring in the top 5 of any challenge, (2) by being the first person to find a bug in a published winning solution or, (3) being the first person to suggest a challenge that I use. The points you can win are:

1st place 20 points

2nd place 10 points

3rd place 7 points

4th place 4 points

5th place 2 points

finding bug 5 points

suggesting challenge 2 points

Here is Raffi’s winning solution:

/*                     HY-PHEN-A-TION                               */
/*                                                             */
/*                   Raffi J. Kasparian                                 */
/*                                                             */
/* Please set the following three defines to appropriate    */
/* values if their default settings are not appropriate.              */

#define AllowMixedCaseDoubleConsonants                  true
/* if, for example, “Ss” or “sS” might occur in the       */
/* middle of the word (as in “paSsion”).                  */

#define AllowZeroLengthWords                           false
/* if the length byte might be a zero.                    */

#define AllowMultipleConsonants                         true
/* if multiple ( >2 ) same-consonants are po“sssss”ible.  */

#define uchar unsigned char
#define ulong unsigned long
#define kHyphen 0x2D
#define v( a ) ( a == 'A' || a == 'a' || \
                 a == 'E' || a == 'e' || \
                 a == 'I' || a == 'i' || \
                 a == 'O' || a == 'o' || \
                 a == 'U' || a == 'u' )

static Boolean vowelTable[128] = {
  v(0), v(1), v(2), v(3), v(4), v(5), v(6), v(7), v(8), 
  v(9), v(10), v(11), v(12), v(13), v(14), v(15), v(16), 
  v(17), v(18), v(19), v(20), v(21), v(22), v(23), v(24), 
  v(25), v(26), v(27), v(28), v(29), v(30), v(31), v(32), 
  v(33), v(34), v(35), v(36), v(37), v(38), v(39), v(40), 
  v(41), v(42), v(43), v(44), v(45), v(46), v(47), v(48), 
  v(49), v(50), v(51), v(52), v(53), v(54), v(55), v(56), 
  v(57), v(58), v(59), v(60), v(61), v(62), v(63), v(64), 
  v(65), v(66), v(67), v(68), v(69), v(70), v(71), v(72), 
  v(73), v(74), v(75), v(76), v(77), v(78), v(79), v(80), 
  v(81), v(82), v(83), v(84), v(85), v(86), v(87), v(88), 
  v(89), v(90), v(91), v(92), v(93), v(94), v(95), v(96), 
  v(97), v(98), v(99), v(100), v(101), v(102), v(103), 
  v(104), v(105), v(106), v(107), v(108), v(109), v(110), 
  v(111), v(112), v(113), v(114), v(115), v(116), v(117), 
  v(118), v(119), v(120), v(121), v(122), v(123), v(124), 
  v(125), v(126), v(127)
};

void *InitHyphenation( ulong maxRAM )
{
  return (void*)vowelTable;
}

void Hyphenate( privateDataPtr, inPtr, outPtr )
  void *privateDataPtr;
  Str255 *inPtr;
  Str255 *outPtr;
{
  #define mIsVowel( a ) ( ((Boolean*)privateDataPtr)[a] )
  #define mIsConsonant( a ) ( ! mIsVowel( a ) )

  #if AllowMixedCaseDoubleConsonants
    #define mIsDoubleConsonant( in )\
      ( *in == ( a = *( in + 1 ) ) || *in == a + 'a' - 'A' \
        || *in == a + 'A' - 'a' )
  #else
    #define mIsDoubleConsonant( in ) ( *in == *( in + 1 ) )
  #endif
  
  register uchar *in, *out, *out0, *inLast, *lastVowel;
  #if AllowMixedCaseDoubleConsonants
    register uchar a;
  #endif
  
  in = *inPtr;
  out = out0 = *outPtr;
  lastVowel = inLast = in + *in;

  /* working from back to front of the word, locate the   */
  /* last vowel not including final ‘e’, ‘es’, or ‘ed.    */
  if( mIsVowel( *lastVowel ) ){
    if( *lastVowel == 'e' || *lastVowel == 'E' ){
      lastVowel--;
      goto FIND_LAST_VOWEL;
    }
    else goto ALGORITHM;
  }
  switch( *lastVowel-- ){
  case 's': case 'd': case 'S': case 'D':
    if( *lastVowel == 'e' || *lastVowel == 'E' )
      lastVowel--;
    break;
  #if AllowZeroLengthWords
    case '\0': goto COPY_TO_END;
  #endif
  }  
  FIND_LAST_VOWEL: do{
    if( lastVowel == in ) goto COPY_TO_END;
    if( mIsVowel( *lastVowel ) ) break;
    lastVowel--;
  }while( true );

  ALGORITHM:  
  /* Working forwards from the beginning of the word                */
  /* until lastVowel is reached, hyphenate every           */
  /* vowel/consonant pair unless the vowel is followed by                       */
  /* a double consonant.  In this case, hyphenate between                    */
  /* the double consonant.  This method meets the             */
  /* hyphenation requirements without having to deal               */
  /* directly with all the letter combination rules.            */
  
  *out++ = *in++; /* copy length byte */
  while( true ){
    while( mIsConsonant( *in ) )
      *out++ = *in++;                    
    do{
      if( in == lastVowel ) goto COPY_TO_END;
      *out++ = *in++;        
    }while( mIsVowel( *in ) );    
    
    /* handle double or multiple consonants               */
    #if AllowMultipleConsonants
      while( mIsDoubleConsonant( in ) ) *out++ = *in++;
    #else
      if( mIsDoubleConsonant( in ) ) *out++ = *in++;
    #endif       
    *out++ = kHyphen; *out++ = *in++; (*out0)++;
  }
  COPY_TO_END: do *out++ = *in++; while( in <= inLast );
  
#undef mIsVowel
#undef mIsConsonant
#undef mIsDoubleConsonant
}

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Microsoft Remote Desktop 8.0.16 - Connec...
With Microsoft Remote Desktop, you can connect to a remote PC and your work resources from almost anywhere. Experience the power of Windows with RemoteFX in a Remote Desktop client designed to help... Read more
Spotify 1.0.4.90. - Stream music, create...
Spotify is a streaming music service that gives you on-demand access to millions of songs. Whether you like driving rock, silky R&B, or grandiose classical music, Spotify's massive catalogue puts... Read more
djay Pro 1.1 - Transform your Mac into a...
djay Pro provides a complete toolkit for performing DJs. Its unique modern interface is built around a sophisticated integration with iTunes and Spotify, giving you instant access to millions of... Read more
Vivaldi 1.0.118.19 - Lightweight browser...
Vivaldi browser. In 1994, two programmers started working on a web browser. Our idea was to make a really fast browser, capable of running on limited hardware, keeping in mind that users are... Read more
Stacks 2.6.11 - New way to create pages...
Stacks is a new way to create pages in RapidWeaver. It's a plugin designed to combine drag-and-drop simplicity with the power of fluid layout. Features: Fluid Layout: Stacks lets you build pages... Read more
xScope 4.1.3 - Onscreen graphic measurem...
xScope is powerful set of tools that are ideal for measuring, inspecting, and testing on-screen graphics and layouts. Its tools float above your desktop windows and can be accessed via a toolbar,... Read more
Cyberduck 4.7 - FTP and SFTP browser. (F...
Cyberduck is a robust FTP/FTP-TLS/SFTP browser for the Mac whose lack of visual clutter and cleverly intuitive features make it easy to use. Support for external editors and system technologies such... Read more
Labels & Addresses 1.7 - Powerful la...
Labels & Addresses is a home and office tool for printing all sorts of labels, envelopes, inventory labels, and price tags. Merge-printing capability makes the program a great tool for holiday... Read more
teleport 1.2.1 - Use one mouse/keyboard...
teleport is a simple utility to let you use one single mouse and keyboard to control several of your Macs. Simply reach the edge of your screen, and your mouse teleports to your other Mac! The... Read more
Apple iMovie 10.0.8 - Edit personal vide...
With an all-new design, Apple iMovie lets you enjoy your videos like never before. Browse your clips more easily, instantly share your favorite moments, and create beautiful HD movies and Hollywood-... Read more

Use Batting Average and the Apple Watch...
Batting Average, by Pixolini, is designed to help you manage your statistics. Every time you go to bat, you can use your Apple Watch to track  your swings, strikes, and hits. [Read more] | Read more »
Celebrate Studio Pango's 3rd Annive...
It is time to party, Pangoland pals! Studio Pango is celebrating their 3rd birthday and their gift to you is a new update to Pangoland. [Read more] | Read more »
Become the World's Most Important D...
Must Deliver, by cherrypick games, is a top-down endless-runner witha healthy dose of the living dead. [Read more] | Read more »
SoundHound + LiveLyrics is Making its De...
SoundHound Inc. has announced that SoundHound + LiveLyrics, will be one of the first third-party apps to hit the Apple Watch. With  SoundHound you'll be able to tap on your watch and have the app recognize the music you are listening to, then have... | Read more »
Adobe Joins the Apple Watch Lineup With...
A whole tidal wave of apps are headed for the Apple Watch, and Adobe has joined in with 3 new ways to enhance your creativity and collaborate with others. The watch apps pair with iPad/iPhone apps to give you total control over your Adobe projects... | Read more »
Z Steel Soldiers, Sequel to Kavcom'...
Kavcom has released Z Steel Soldiers, which continues the story of the comedic RTS originally created by the Bitmap Brothers. [Read more] | Read more »
Seene Lets You Create 3D Images With You...
Seene, by Obvious Engineering, is a 3D capture app that's meant to allow you to create visually stunning 3D images with a tap of your finger, and then share them as a 3D photo, video or gif. [Read more] | Read more »
Lost Within - Tips, Tricks, and Strategi...
Have you just downloaded Lost Within and are you in need of a guiding hand? While it’s not the toughest of games out there you might still want some helpful tips to get you started. [Read more] | Read more »
Entertain Your Pet With Your Watch With...
The Petcube Camera is a device that lets you use live video to check in on your pet, talk to them, and play with them using a laser pointer - all while you're away. And the Petcube app is coming to the Apple Watch, so you'll be able to hang out with... | Read more »
Now You Can Manage Your Line2 Calls With...
You'll be able to get your Line2 cloud phone service on the Apple Watch very soon. The watch app can send and receive messages using hands-free voice dictation, or by selecting from a list of provided responses. [Read more] | Read more »

Price Scanner via MacPrices.net

Zoho Business Apps for Apple Watch Put Select...
Pleasanton, California based Zoho has launched Zoho Business Apps for Apple Watch, a line of apps that extends Zoho business applications to let users perform select functions from an Apple Watch.... Read more
Universal Stylus Initiative Launched to Creat...
OEMs, stylus and touch controller manufacturers have announced the launch of Universal Stylus Initiative (USI), a new organization formed to develop and promote an industry specification for an... Read more
Amazon Shopping App for Apple Watch
With the new Amazon shopping app for Apple Watch, Amazon customers with one of the wearable devices can simply tap the app on the watch to purchase items in seconds, or save an idea for later. The... Read more
Intel Compute Stick: A New Mini-Computing For...
The Intel Compute Stick, a new pocket-sized computer based on a quad-core Intel Atom processor running Windows 8.1 with Bing, is available now through Intel Authorized Dealers across much of the... Read more
Heal to Launch First One-Touch House Call Doc...
Santa Monica, California based Heal, a pioneer in on-demand personal health care services — will offer the first one-touch, on-demand house call doctor app for the Apple Watch. Heal’s Watch app,... Read more
Mac Notebooks: Avoiding MagSafe Power Adapter...
Apple Support says proper usage, care, and maintenance of Your Mac notebook’s MagSafe power adapter can substantially increase the the adapter’s service life. Of course, MagSafe itself is an Apple... Read more
12″ Retina MacBook In Shootout With Air And P...
BareFeats’ rob-ART morgan has posted another comparison of the 12″ MacBook with other Mac laptops, noting that the general goodness of all Mac laptops can make which one to purchase a tough decision... Read more
FileMaker Go for iPad and iPhone: Over 1.5 Mi...
FileMaker has announced that its FileMaker Go for iPad and iPhone app has surpassed 1.5 million downloads from the iTunes App Store. The milestone confirms the continued popularity of the FileMaker... Read more
Sale! 13-inch 2.7GHz Retina MacBook Pro for $...
 Best Buy has the new 2015 13″ 2.7GHz/128GB Retina MacBook Pro on sale for $1099 – $200 off MSRP. Choose free shipping or free local store pickup (if available). Price for online orders only, in-... Read more
Minimalist MacBook Confirms Death of Steve Jo...
ReadWrite’s Adriana Lee has posted a eulogy for the “Digital Hub” concept Steve Jobs first proposed back in 2001, declaring the new 12-inch MacBook with its single, over-subscribed USB-C port to be... Read more

Jobs Board

*Apple* Client Systems Solution Specialist -...
…drive revenue and profit in assigned sales segment and/or region specific to the Apple brand and product sets. This person will work directly with CDW Account Managers Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Support Technician IV - Jack Henry a...
Job Description Jack Henry & Associates is seeking an Apple Support Technician. This position while acting independently, ensures the proper day-to-day control of Read more
*Apple* Client Systems Solution Specialist -...
…drive revenue and profit in assigned sales segment and/or region specific to the Apple brand and product sets. This person will work directly with CDW Account Managers Read more
*Apple* Software Support - Casper (Can work...
…experience . Full knowledge of Mac OS X and prior . Mac OSX / Server . Apple Remote Desktop . Process Documentation . Ability to prioritize multiple tasks in a fast pace Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.