TweetFollow Us on Twitter

May 95 Challenge
Volume Number:11
Issue Number:5
Column Tag:Programmer’s Challenge

Programmer’s Challenge

By Mike Scanlin, Mountain View, CA

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

Hy-phen-a-tion

Hyphenation algorithms come in two flavors: rule-based and dictionary-based. Of the two, dictionary-based is more reliable but has the downside of requiring a lot of storage space. Rule-based methods require considerably less space and have the option of using an “exceptions” dictionary to improve accuracy. This month’s Challenge is to implement a rule-based hyphenation algorithm.

The algorithm is this: Each part of the word on either side of the hyphen must include a vowel, not counting a final e, es or ed. The part of the word after the hyphen cannot begin with a vowel or a double consonant. No break is made between any two of the following letter combinations: sh, gh, ph, ch, th, wh, gr, pr, cr, tr, wr, br, fr, dr, vowel-r, vowel-n, or om. That means that if any two of those pairs occur next to each other, you can’t break them apart (i.e. ‘from’ contains ‘fr’ and ‘om’, which are both on the list; therefore you would not split it between the ‘r’ and the ‘o’). The letter ‘y’ is not a vowel.

The two routines you’ll write are:

void *
InitHyphenation(maxRAM)
ulong   maxRAM;

void
Hyphenate(privateDataPtr, inPtr, outPtr)
void  *privateDataPtr;
Str255  *inPtr;
Str255  *outPtr;

The InitHyphenation routine is an untimed routine called once that can set up whatever tables you might want to use. It must not allocate more than maxRAM bytes, which will be between 16K and 64K.

Hyphenate is the routine that does the work. PrivateDataPtr is the return value from the InitHyphenation routine. InPtr is a pointer to a read-only unhyphenated Pascal word (containing only letters ‘a’..‘z’ and ‘A’..‘Z’). OutPtr is a pointer to 256 bytes of space where you store the hyphenated word. You need to preserve the case of the input and you should insert a kHyphen byte (0x2D) everywhere the above algorithm tells you to (yes, the complete output is guaranteed to fit within a Str255).

Note that this algorithm is valid for English only. It will find about 70% of all valid hyphens and will make mistakes about 45% of the time. It is assumed that if this was part of a real application that a hyphenation exception word list would be kept. That list would be checked before calling this function. You, however, don’t need to be concerned with that.

Write to me if you have any questions.

Two Months Ago Winner

Congrats to Gustav Larsson (Mountain View, CA) for winning the Method Dispatcher Challenge. Gustav was a virtual unknown to this column a few months ago but he is rising fast in the Top 20 rankings. The 20 points he wins this month move him from 10th place to 4th place.

Here are the times and code sizes for each entry. 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

Gustav Larsson (40) 261 1040

Kevin Cutts (36) 304 266

Jeff Mallett (27) 338 1192

Xan Gregg 349 158

Ernst Munter (51) 385 1466

Thomas Studer 437 572

David Howarth 632 130

Scanlin’s brute force method 420 122

Everyone who entered implemented some kind of cache. Gustav chose a 10-way set-associative cache. He splits the 16K of usable cache space into 256 cache sets, each of which holds 10 entries. He uses a hash based on the class and method numbers to map to one of the 256 caches. Once he’s got that he checks the 10 entries for a match. If he doesn’t find a match he uses an efficient binary search to look for the method within the class.

In designing any cache, the choice of hash function and amount of set-associativity (if any) is highly dependent on your data and access pattern. Gustav’s code could be tuned for a variety of efficient cache uses. Nice job, Gustav.

Poker Winner Disqualified

Turns out that I failed to do adequate testing on the winning entry for the Poker Hand Evaluator Challenge, in which Kevin Cutts was the published winner. Unfortunately, I’m going to have to retro-actively disqualify Kevin and award the 1st place prize to Gustav Larsson. My apologies to Kevin and the other MacTech readers. Rather than publish Gustav’s well-commented winning solution (it’s quite long) I’ll make it available via e-mail. If you’re interested, send me a note at scanlin@genmagic.com or at any of the Programmer Challenge electronic addresses (see p. 2).

This latent win for Gustav means that he’s 3 for 3 in the last 3 challenges, which is an unmatched winning streak. Congrats, Gustav! Also, Dave Darrah was the first person to point out the flaws in Kevin’s code and so he receives 5 extra points in the cumulative point totals for doing so. Thanks, Dave!

Top 20 Contestants of All Time

Here are the Top 20 Contestants for the 33 Programmer’s Challenges to date. The numbers below include points awarded for this months’ top 5 entrants. (Note: ties are listed alphabetically by last name -- there are 23 people listed this month because 7 people have 20 points each.)

1. Boonstra, Bob 176

2. Karsh, Bill 71

3. Stenger, Allen 65

4. Larsson, Gustav 60

5. Munter, Ernst 53

6. Riha, Stepan 51

7. Goebel, James 49

8. Cutts, Kevin 46

9. Nepsund, Ronald 40

10. Vineyard, Jeremy 40

11. Darrah, Dave 34

12. Mallet, Jeff 34

13. Landry, Larry 29

14. Elwertowski, Tom 24

15. Kasparian, Raffi 24

16. Lee, Johnny 22

17. Anderson, Troy 20

18. Burgoyne, Nick 20

19. Galway, Will 20

20. Israelson, Steve 20

21. Landweber, Greg 20

22. Noll, Bob 20

23. 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 Gustav’s winning solution:

Dispatch.c

Copyright ©1995 Gustav K. Larsson

#define kMethodNotFound ((void *) 0)
#define kClassNotFound  ((void *) -1)

typedef unsigned char uchar;
typedef unsigned short ushort;
typedef unsigned long ulong;

typedef ushort  ClassID;
typedef ushort  MethodNumber;
typedef void *  MethodAddress;

typedef struct {
  MethodNumber  methodNumber;
  MethodAddress methodAddress;
} MethodEntry;

typedef struct {
  ushort        inheritedCount;
  ushort        inheritedClasses[15];
  MethodNumber  largestMethodNumber;
  ushort        methodCount;
  MethodEntry   methods[];
} Class, *ClassPtr;

/* Each block in the cache is 64 bytes and holds 10 entries. The id field distinguishes class/method pairs 
that map to the same cache block. The hits field has a bit for each entry, which is set whenever there is a 
hit on the entry.  The "next" field is 0..9 and indicates where to check first when deciding which entry to replace. 
*/

#define BLOCK_SIZE 10

typedef struct {
  ushort          id [ BLOCK_SIZE ];
  ushort          hits;
  ushort          next;
  MethodAddress   methodAddress [ BLOCK_SIZE ];
} CacheBlock;

static CacheBlock Cache[256]; /* exactly 16K */
GetClassPtr
extern ClassPtr GetClassPtr( ClassID );
MethodAddress FindMethod( ClassID, MethodNumber );
static MethodAddress HandleMiss( ClassID, MethodNumber,
                                 CacheBlock *, ushort );
FindMethod
MethodAddress
FindMethod( ClassID classID, MethodNumber methodNumber )
{
  register ulong hash;
  register ushort *idPtr;
  register CacheBlock *block;
Check cache for this class & method.

/* First, generate a hash key that is unique for each class/method pair. The formula classID + 437 * method 
works since 437 is greater than the highest class ID, 400. The ideal multiplier depends heavily on the distribution 
of class/method pairs, but 437 seems to give a reasonable spread under a variety of conditions.
    The low byte of the hash key becomes the block number, and the higher bytes become the "id" (to distinguish 
class/method pairs that map to the same block). Add one to the id so it is never zero (zero indicates an unused 
cache entry). */

  hash = classID + 437L * methodNumber;
  block = &Cache[ (uchar)hash ];
  hash = (hash >> 8) + 1;   /* now hash holds just the id */

  idPtr = block->id;
  if ( *idPtr++ == (ushort)hash ) goto hit0;
  if ( *idPtr++ == (ushort)hash ) goto hit1;
  if ( *idPtr++ == (ushort)hash ) goto hit2;
  if ( *idPtr++ == (ushort)hash ) goto hit3;
  if ( *idPtr++ == (ushort)hash ) goto hit4;
  if ( *idPtr++ == (ushort)hash ) goto hit5;
  if ( *idPtr++ == (ushort)hash ) goto hit6;
  if ( *idPtr++ == (ushort)hash ) goto hit7;
  if ( *idPtr++ == (ushort)hash ) goto hit8;
  if ( *idPtr++ == (ushort)hash ) goto hit9;

  return HandleMiss( classID, methodNumber,
                     block, (ushort)hash );

/* Handle cache hit */
hit0: block->hits |= 0x001;  return block->methodAddress[0];
hit1: block->hits |= 0x002;  return block->methodAddress[1];
hit2: block->hits |= 0x004;  return block->methodAddress[2];
hit3: block->hits |= 0x008;  return block->methodAddress[3];
hit4: block->hits |= 0x010;  return block->methodAddress[4];
hit5: block->hits |= 0x020;  return block->methodAddress[5];
hit6: block->hits |= 0x040;  return block->methodAddress[6];
hit7: block->hits |= 0x080;  return block->methodAddress[7];
hit8: block->hits |= 0x100;  return block->methodAddress[8];
hit9: block->hits |= 0x200;  return block->methodAddress[9];
}
HandleMiss
static MethodAddress
HandleMiss( ClassID classID, MethodNumber methodNumber,
            CacheBlock *blockPtr, ushort id )
{
  register ClassPtr classPtr;
  MethodAddress methodAddress;
  register ushort *temp;  /* shared address register */

  /* Not in cache, so look it up the hard way */
  classPtr = GetClassPtr( classID );
  if ( classPtr != kClassNotFound ) {

    /* Look in this class. Use a binary search. */
    {
      register MethodEntry *methods = classPtr->methods;
      ushort searchSize = classPtr->methodCount;
      register MethodNumber methodReg = methodNumber;
                                /* method # in a register */

/* Unroll the binary search for the most common cases. The BINARY macro reduces the search to progressively 
more elementary cases. If classPtr->methodCount is greater than 32, we run a general binary search until 
the search is reduced to an unrolled case.  */

continueBinarySearch:
      switch ( searchSize )
      {
        bin2: case 2:
          if ( methods[1].methodNumber == methodReg ) {
            methodAddress = methods[1].methodAddress;
            goto addCache;
          }
          /* else fall through... */
        bin1: case 1:
          if ( methods[0].methodNumber == methodReg ) {
            methodAddress = methods[0].methodAddress;
            goto addCache;
          }
          else goto checkSuperclasses;

      #define BINARY(mid,mid1)                        \
        if ( methodReg < methods[mid].methodNumber )  \
          goto bin##mid;  /* like "hi = mid" */       \
        else {                                        \
          methods += mid; /* like "lo = mid" */       \
          goto bin##mid1;                             \
        }

        /* binN: case N: BINARY(N/2,(N+1)/2) */
        bin3:  case  3: BINARY(1,2)
        bin4:  case  4: BINARY(2,2)
        bin5:  case  5: BINARY(2,3)
        bin6:  case  6: BINARY(3,3)
        bin7:  case  7: BINARY(3,4)
        bin8:  case  8: BINARY(4,4)
        bin9:  case  9: BINARY(4,5)
        bin10: case 10: BINARY(5,5)
        bin11: case 11: BINARY(5,6)
        bin12: case 12: BINARY(6,6)
        bin13: case 13: BINARY(6,7)
        bin14: case 14: BINARY(7,7)
        bin15: case 15: BINARY(7,8)
        bin16: case 16: BINARY(8,8)
        bin17: case 17: BINARY(8,9)
        bin18: case 18: BINARY(9,9)
        bin19: case 19: BINARY(9,10)
        bin20: case 20: BINARY(10,10)
        bin21: case 21: BINARY(10,11)
        bin22: case 22: BINARY(11,11)
        bin23: case 23: BINARY(11,12)
        bin24: case 24: BINARY(12,12)
        bin25: case 25: BINARY(12,13)
        bin26: case 26: BINARY(13,13)
        bin27: case 27: BINARY(13,14)
        bin28: case 28: BINARY(14,14)
        bin29: case 29: BINARY(14,15)
        bin30: case 30: BINARY(15,15)
        bin31: case 31: BINARY(15,16)
        bin32: case 32: BINARY(16,16)

        #define NUM_UNROLLED 32 /* # of unrolled cases */

        default:
          if (methodReg <= classPtr->largestMethodNumber) {
            register ushort lo, mid, hi, mn;
            lo = 0;
            hi = classPtr->methodCount - 1;
            while ( lo + NUM_UNROLLED - 1 < hi ) {
              mid = (lo + hi) >> 1;
              mn = methods[mid].methodNumber;
              if ( methodReg < mn )
                hi = mid;
              else if ( methodReg > mn )
                lo = mid;
              else {
                methodAddress = methods[mid].methodAddress;
                goto addCache;
              }
            }
            /* reduced to an unrolled case */
            searchSize = hi-lo+1;
            methods += lo;
            goto continueBinarySearch;
          }
      }
    }

/* Look in superclasses. Eliminating the recursion by keeping a custom stack of critical variables doesn't 
buy us much. Recursion also makes the code clearer. */

checkSuperclasses:
    {
      register ulong i, max = classPtr->inheritedCount;
           /* shared address register points into class list */
      temp = classPtr->inheritedClasses;

      for ( i = 0; i < max; i++ ) {
        methodAddress = FindMethod(*temp++, methodNumber);
        if ( methodAddress != kMethodNotFound )
          goto addCache;
      }
    }
  }

/* There are two ways to get here: classPtr is kClassNotFound (hopefully rare), or the method was not found 
in any of the superclasses. Either way, put a "not found" entry into the cache. This helps when searching 
complicated inheritance hierarchies or repeatedly looking up the same method in several related subclasses. 
*/

  methodAddress = kMethodNotFound;

Add an entry to the cache.
addCache:

// shared address register holds block pointer
  temp = (ushort*) blockPtr;
  #define block ((CacheBlock*) temp)
  {
    register ulong hits = block->hits;
    register ulong next = block->next;
    register ulong mask = 1L << next;

/* Choose the entry to replace. Look for a cleared bit in "hits" starting at "next". If all the bits are 1 initially, 
go all the way around; we are guaranteed to stop since we clear bits as we go. */

    while ( hits & mask ) {
      hits &= ~mask;              /* no, clear the bit */
      mask <<= 1;                 /* and try next bit */
      if ( mask == (1 << BLOCK_SIZE) )
        mask = 1;
      next++;
    }
    if ( next >= BLOCK_SIZE )
      next -= BLOCK_SIZE;

    block->methodAddress[ next ] = methodAddress;
    block->id[ next ] = id;
    block->hits = hits;
    block->next = ( next < BLOCK_SIZE-1 ? next+1 : 0 );
  }

  return methodAddress;
}

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

FileMaker Pro 19.4.2 - Quickly build cus...
FileMaker Pro is the tool you use to create a custom app. You also use FileMaker Pro to access your app on a computer. Start by importing data from a spreadsheet or using a built-in Starter app to... Read more
Adobe Illustrator 26.0.3 - Professional...
You can download Adobe Illustrator for Mac as a part of Creative Cloud for only $20.99/month. Adobe Illustrator for Mac is the vector graphics classics in the design industry. It is a digital... Read more
WhatRoute 2.4.9 - Geographically trace o...
WhatRoute is designed to find the names of all the routers an IP packet passes through on its way from your Mac to a destination host. It also measures the round-trip time from your Mac to the router... Read more
Notion 2.0.20 - A unified workspace for...
Notion is the unified workspace for modern teams. Notion Features: Integration with Slack Documents Wikis Tasks Release notes were unavailable when this listing was updated. Download Now]]> Read more
Monterey Cache Cleaner 17.0.2 - Clear ca...
Monterey Cache Cleaner is an award-winning general-purpose tool for macOS X. MCC makes system maintenance simple with an easy point-and-click interface to many macOS X functions. Novice and expert... Read more
Firetask Pro 4.6.8 - Innovative task man...
Firetask Pro represents the next generation of easy-to-use, project-oriented task management apps. By combining David Allen's powerful Getting Things Done (GTD®) approach with classical task... Read more
Smultron 13.0.4 - Easy-to-use, powerful...
Smultron 13 is the text editor for all of us. Smultron is powerful and confident without being complicated. Its elegance and simplicity helps everyone being creative and to write and edit all sorts... Read more
Box Sync 4.0.8057 - Online synchronizati...
Box Sync gives you a hard-drive in the Cloud for online storage. Note: You must first sign up to use Box. What if the files you need are on your laptop -- but you're on the road with your iPhone? No... Read more
Audio Hijack 3.8.10 - Record and enhance...
Audio Hijack (was Audio Hijack Pro) drastically changes the way you use audio on your computer, giving you the freedom to listen to audio when you want and how you want. Record and enhance any audio... Read more
Direct Mail 6.0.1 - Create and send grea...
Direct Mail is an easy-to-use, fully-featured email marketing app purpose-built for macOS. Create, send, and track great looking email campaigns that get results. Start your newsletter by selecting... Read more

Latest Forum Discussions

See All

Hopefully Not Jared’s Last Show – The To...
My suspicions from last week were correct, and after my two kids tested positive for Covid last week both my wife and I have now tested positive as well. It seems you just can’t escape this stuff lately. Thankfully the two little ones are pretty... | Read more »
TouchArcade Game of the Week: ‘Micro RPG...
I feel like idle games are one of those perfect fits for the mobile platform. Not that they replace more involved gaming experiences when you’re in the mood for that, but they do fit in alongside other types of games just fine as a “go to" when you... | Read more »
‘Phantom Blade: Executioners’ Closed Bet...
Phantom Blade: Executioners is holding a small-scale technical test that lets players get first dibs on the KungFuPunk action RPG. Offered to selected players only, S-Game’s first Closed Beta Test will provide players with limited edition in-game... | Read more »
New ‘Warhammer 40,000: Tacticus’ Video S...
Back in September Snowprint Studios, who you may know from their previous Legend of Solgard or Rivengard, announced that they’d partnered up with Games Workshop to put out a new tactical game in the Warhammer 40,000 universe titled Warhammer 40,000... | Read more »
SwitchArcade Round-Up: ‘Pokemon Legends:...
Hello gentle readers, and welcome to the SwitchArcade Round-Up for January 28th, 2022. We’ve got a bunch of new releases to look at today, with a few big hitters, a few mid-level diversions, and a healthy supply of compost. Since it’s Friday, we... | Read more »
Phantom Blade: Executioners, S-Game...
S-Game has kicked off its first Closed Beta Test for Phantom Blade: Executioners, inviting a selected few to get first dibs on the upcoming KungFuPunk action RPG on mobile. The CBT officially begins this January 28th, and beta testers will receive... | Read more »
‘Infinite Galaxy’ First Anniversary: Cel...
Cultivating a new generation of valiant commanders across 240 countries worldwide, Infinite Galaxy has quenched players’ thirst to explore the vastness of space – and there are only more intergalactic adventures to embark on from here on out. Camel... | Read more »
War and Order: How to brave the cold in...
War and Order's 6th-anniversary celebrations are underway, and all in good time too - this season not only brings about fabulous festivities, but it also lets players experience the harsh winter in an entirely new way. [Read more] | Read more »
‘Hidden Folks+’ Is This Week’s New Apple...
The original Hidden Folks from Adriaan de Jongh is an excellent hidden objects game featuring hand drawn visuals. It is an absolute joy to play, and it has now released on Apple Arcade in the form of Hidden Folks+ () as an App Store great. If you’... | Read more »
Mini Metro’s First Big Update of 2022 Ad...
Last year saw great updates for Dinosaur Polo Club’s Mini Metro ($3.99) which is also available on Apple Arcade as an App Store Great. | Read more »

Price Scanner via MacPrices.net

Apple has clearance 2020 13″ MacBook Airs ava...
Apple has clearance, Certified Refurbished, 2020 13″ Intel-based MacBook Airs in stock today starting at only $719 and up to $370 off original MSRP. Each MacBook features a new outer case, comes with... Read more
The cheapest iPhones for sale today at Apple...
Apple has restocked Apple Certified Refurbished iPhone 8 models starting at only $359. Each refurbished iPhone comes with a fresh external case, standard Apple 1-year warranty, and free shipping.... Read more
14″ MacBook Pro with Apple M1 Max CPU now in...
Looking for a new 14″ MacBook Pro with an Apple M1 Max CPU? Stock is finally trickling into Apple resellers. B&H has Silver 14″ M1 Max MacBook Pros in stock today for $2899 including free 1-2 day... Read more
14″ MacBook Pros with Apple M1 Pro CPUs are i...
Amazon is reporting stock of 14″ MacBook Pros with M1 Pro CPUs today with a $50 discount. Shipping is free, and delivery is available by February 1st for most configurations. Be sure to make your... Read more
Apple has restocked 13″ M1 MacBook Pros for $...
Apple has restocked a full line of 13″ M1 MacBook Pros available Certified Refurbished, starting at only $1099 and up to $230 off original MSRP. These are the cheapest M1 MacBook Pros for sale today... Read more
Apple’s AirPods Max headphones are on sale fo...
Amazon has Silver, Blue, and Space Gray Apple AirPods Max headphones on sale today for $100 off MSRP. Shipping is free, and all models are in stock today. Their price is the lowest currently... Read more
Open a new line of service at Verizon and get...
Verizon is giving away 64GB Apple iPhone 12 minis or your choice of an iPhone 11 to customers who choose one of these phones and open a new line of service. Offer is available online only, and no... Read more
Open-box 13″ M1 MacBook Airs now available st...
QuickShip Electronics has open-box return 13″ M1 MacBook Airs in stock and on sale for $200-$400 off MSRP on their eBay store right now with free express delivery. According to QuickShip, “The item... Read more
Verizon’s 2022 iPad promo: $100-$310 off any...
Verizon has cellular-capable iPads on sale for $100-$310 off MSRP when purchased with an Unlimited service plan. Sale price is applied to your account monthly over a 24 or 30 month period, depending... Read more
Sunday Sale: Apple AirPods are on sale for up...
Amazon has Apple AirPods on sale for $10-$100 off MSRP today, depending on the model. All are in stock today with free delivery: – AirPods Max headphones (Blue): $449 $100 off MSRP – AirPods Max... Read more

Jobs Board

Registered Nurse (RN) Employee Health PSJH -...
…is calling for a Registered Nurse (RN) Employee Health PSJH to our location in Apple Valley, CA.** We are seeking a Registered Nurse (RN) Employee Health PSJH to be Read more
Systems Administrator - Pearson (United State...
…and troubleshoot Windows operating systems (workstation and server), laptop computers, Apple iPads, Chromebooks and printers** + **Administer and troubleshoot all Read more
IT Assistant Level 1- IT Desktop Support Anal...
…providing tier-1 or better IT help desk support in a large Windows and Apple environment * Experience using IT Service Desk Management Software * Knowledge of IT Read more
Human Resources Business Partner PSJH - Provi...
…**is calling a** **Human Resources Business Partner, PSJH** **to our location in Apple Valley, CA.** **Applicants that meet qualifications will receive a text with Read more
Manager Community Health Investment Programs...
…is calling a Manager Community Health Investment Programs PSJH to our location in Apple Valley, CA.** **Qualified candidates will be invited to do a self-paced video Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.