TweetFollow Us on Twitter

Sep 93 Challenge
Volume Number:9
Issue Number:9
Column Tag:Programmers’ Challenge

Programmers’ Challenge

By Mike Scanlin, MacTech Magazine Regular Contributing Author

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

BLOCKMOVEBITS

Because I’ve had several requests for it and because I’ve wanted to do it for a while and because this column is primarily about about efficient coding and because the lazy days of summer are over and it’s time to get serious, I’m happy to say that September will from now on be the annual MacTech Assembly Language Programmer’s Challenge. When submitting entries to September challenges you may use as much in-line 68040 assembly source inside of a Think C function as you like. In fact, a C wrapper around a 100% assembly language solution is allowed (and preferred). You should optimize for the 040 cause that’s what I’ll run the time tests on (and your code can require an 020, 030 and/or 040 if it wants to). You must preserve all registers except A0-A1/D0-D2. OK. Let’s get to it.

This first assembly language challenge is to move a block of contiguous bits when given the number of bits to move along with source and destination byte and bit offsets (the source and destination bit ranges do not overlap). This could be used, for example, inside a bit-blitting graphics routine that’s working with bitMaps.

The prototype of the function you write is:

void BlockMoveBits(srcBytePtr, 
 destBytePtr, srcBitOffset, 
 destBitOffset, bitCount)
char    *srcBytePtr;
char    *destBytePtr;
unsigned char    srcBitOffset;
unsigned char    destBitOffset;
unsigned short bitCount;

The srcBytePtr and destBytePtr point to the bytes containing the first source bit and first destination bit. The actual bits are at bit offsets srcBitOffset and destBitOffset (both of which will be less than 8). The most number of bits you can move at one time with this routine is 2^16 - 1 or 65535 (it’s possible that bitCount will be zero, which means you should move zero bits, not 64K bits). You should not disturb any of the bits in the destination bytes that aren’t part of the move.

Here’s an example. Say srcBitOffset is 2, destBitOffset is 5 and bitCount is 10. You have the following before the move (‘s’ is a source bit, ‘d’ is a destination bit and the ‘S’ bits (capital S) are going to be copied:

bit position : 76543210 76543210
srcBytePtr  -> ssSSSSSS SSSSssss
destBytePtr -> dddddddd dddddddd

and you have this after the move:

bit position : 76543210 76543210
srcBytePtr  -> ssSSSSSS SSSSssss
destBytePtr -> dddddSSS SSSSSSSd

It’s very likely that your implementation will have this shell:

void BlockMoveBits(srcBytePtr, 
 destBytePtr, srcBitOffset, 
 destBitOffset, bitCount)
char    *srcBytePtr;
char    *destBytePtr;
unsigned char    srcBitOffset;
unsigned char    destBitOffset;
unsigned short bitCount;
{
 asm {
 ;get parameters into registers
 Move.L srcBytePtr,A0
 Move.L destBytePtr,A1
 ... and so on
 }
}

Please note that because of the increased level of difficulty of reading assembly compared to C, it is very important that your code contains at least a few comments explaining what’s going on. I don’t want to see 200 lines of blazingly fast completely undocumented code. That won’t be of much use to anyone. And use meaningful labels where you can (rather than randomly ordered numeric ones from @258 to @431 or whatever).

TWO MONTHS AGO WINNER

I guess I scared away too many people with my “don’t use MoveWindow or SizeWindow” suggestion in the Tile Windows challenge because I only received three entries this month. However, all three entrants managed to find ways around using those traps and their times were very close to each other (and all three were at least an order of magnitude faster than the MoveWindow/SizeWindow equivalent). Congrats to Raffi Kasparian (Baltimore, MD) for being somewhat faster than the other guys. Raffi’s performance gain comes from manipulating some of the window’s fields directly, which is less than ideal in terms of future compatibility but it works on today’s machines so I’ll let it stand.

Here are the times (for tiling 80 windows) and sizes:

Name bytes ticks

Raffi Kasparian 716 81

Jordan Zimmerman 948 123

Ken Franklin/Michael Staw 806 126

Note that tiling 80 windows in 2 seconds (120 ticks) or less is quite fast. MPW, for comparison, took 10 seconds to tile 20 windows (and I found out that the “New” menu item becomes disabled after you create 45 Untitled windows).

The key to winning this challenge was to make use of the routines MovePortTo, PortSize, PaintBehind and CalcVisBehind. If you do it right then you can have the entire desktop (spread over multiple devices) updated with all the new windows blinking into place with a single call to PaintBehind. It’s really interesting to trap on PaintBehind in a debugger and then to step over that one trap and watch the whole desktop get rearranged (after all ports have been positioned and sized correctly, of course).

Since the winning solution does things in a less than future compatible way (it doesn’t call the window’s defProc to calculate the new regions, for instance) and since my goal with this challenge was to release a generic, efficient window tiling and stacking mechanism into the world, I’ve included some of my own code after Raffi’s.

If you think about minimal screen updating, which parts of the desktop need to be invalidated by rearranging the windows? The answer is the sum of the strucRgns in the windows’ old positions and the sum of the strucRgns in the windows’ new positions. No other area on the screen needs to be invalidated or redrawn. Therefore, my routine keeps track of the sum of these two sets of regions as it works. The resulting region, sumOfStructRgns, is then used as the clobberedRgn parameter to PaintBehind and CalcVisBehind. Any desktop pixel or background app pixel not in this region is not redrawn (i.e. there is no unnecessary flicker).

My routine, TileStackWindows, takes a function pointer parameter to a proc you write that does something with a list of windows inside a given rectangle (the function callback is similar to the challenge’s TileWindows function). This callback is called once per device, with the device’s gdRect given as the rect (inset a few pixels) and the list of windows set to all windows that are more on that device than on any other device. Thus, TileStackWindows is a generic, per-device window rearranging routine. All you have to do is come up with interesting tiling algorithms and bake them into the proc you pass to TileStackWindows. The efficient updating of the desktop and region maintenance is taken care of for you.

There are a couple of restrictions for the callback. First, it must resize a window before it repositions a window. Second, it must call MySizeWindow and MyMoveWindow instead of SizeWindow and MoveWindow. The callback should return TRUE if it moved or sized at least one window and FALSE if it did nothing. The reason for this is because if you have a Tile Windows menu item in your application and the user chooses it twice in a row, it is nice if the second time it is chosen the code is smart enough to see that things are already as they should be and does not cause any flickering or redrawing to take place.

An example callback function, StackWindows, is given here. It takes advantage of the fact that the list of windows it is passed is in order from the frontmost window to the backmost window (for that device). The last window in the list (the backmost) ends up being the largest window after the set has been stacked and the frontmost window (first in the list) ends up being the smallest window after the set has been stacked. It is done this way so that you can read all window titles after they’ve been stacked.

If you want to do tiling rather than stacking, all you have to do is replace StackWindows with your own TileWindows function and come up with a way to calculate each window’s new size and position. Hopefully application writers who have tiling and stacking options within their programs (including MPW) will implement this type of a scheme so that we no longer have to wait so long while we watch windows being moved and sized one at a time with maximum intermediate screen updating.

Here’s Raffi’s winning solution followed by my own version of a generic window tiling/stacking routine and a piece of test code so you can try it out:

TileWindows.c Listing
/*----------------------------------------------------
TileWindows
by Raffi Kasparian
----------------------------------------------------*/
#define StackingOffset 10
 
void TileWindows(enclosingRectPtr, windowPtrArray,
                 windowCount, pixelsBetween,
                 minHorzSize, minVertSize)
 
Rect            *enclosingRectPtr;
WindowPtr       windowPtrArray[];
unsigned short  windowCount;
unsigned short  pixelsBetween;
unsigned short  minHorzSize;
unsigned short  minVertSize;
 
#define mx minHorzSize
#define my minVertSize
#define d  pixelsBetween
 
#define struc  ((WindowPeek)(windowPtrArray[num]))->strucRgn
#define strucL (**struc).rgnBBox.left
#define strucT (**struc).rgnBBox.top
#define strucR (**struc).rgnBBox.right
#define strucB (**struc).rgnBBox.bottom
 
#define cont  ((WindowPeek)(windowPtrArray[num]))->contRgn
#define contL (**cont).rgnBBox.left
#define contT (**cont).rgnBBox.top
#define contR (**cont).rgnBBox.right
#define contB (**cont).rgnBBox.bottom
 
#define pBits  windowPtrArray[num]->portBits.bounds
#define pBitsL pBits.left
#define pBitsT pBits.top
#define pBitsR pBits.right
#define pBitsB pBits.bottom
 
#define pRect  windowPtrArray[num]->portRect
#define pRectL pRect.left
#define pRectT pRect.top
#define pRectR pRect.right
#define pRectB pRect.bottom
 
{
 register short dL, dT, dR, dB, BR, x, y, maxx, maxy,
                num, rL, rT, rR, rB;
 Rect           er = *enclosingRectPtr;
 
#define erL er.left
#define erT er.top
#define erR er.right
#define erB er.bottom
 
 num = 0;
 
 while (true) {
 
  maxy = (erB - erT + d)/(my + d);
  maxx = (erR - erL + d)/(mx + d);
  if ((BR = maxx * maxy) > windowCount) {
   maxx = (windowCount - 1) / maxy + 1;
   maxy = (windowCount - 1) / maxx + 1;
   BR = windowCount;
  }
  BR--;
 
  if (num <= BR) {
   mx = ((erR - erL) - ((maxx - 1) * d)) / maxx;
   my = ((erB - erT) - ((maxy - 1) * d)) / maxy;
  }
 
  rT = erT - (my + d);
  for (y = 1; y <= maxy; y++) {
   rL = erL - (mx + d);
   rT += my + d;
   rB = (y == maxy) && (num <= BR) ? erB : rT + my;
   for (x = 1; x <= maxx; x++, num++) {
 
    rL += mx + d;
    rR = ((x == maxx) && (num <= BR)) ||
      (num == BR) ? erR : rL + mx;
 
    dL = rL - strucL;
    dT = rT - strucT;
    dR = rR - strucR;
    dB = rB - strucB;
 
    SetRectRgn(struc, rL, rT, rR, rB);
    SetRectRgn(cont, contL + dL, contT + dT,
      contR + dR,  contB + dB);
      
    pBitsL -= dL;
    pBitsT -= dT;
    pBitsR -= dL;
    pBitsB -= dT;
 
    pRectR = contR - contL + pRectL;
    pRectB = contB - contT + pRectT;
 
    if (num == windowCount - 1) {
     PaintBehind((WindowPeek)FrontWindow(),
       GrayRgn);
     CalcVisBehind((WindowPeek)FrontWindow(),
       GrayRgn);
     return;
    }
   }
  }
  if (erR - erL - StackingOffset >= mx)
   erL += StackingOffset;
  if (erB - erT - StackingOffset >= my)
   erT += StackingOffset;
 }
}
TileStackWindows.h Listing
/*****************************************************
 * TileStackWindowsWindows.h
 ****************************************************/

/*****************************************************
 * typedefs
 ****************************************************/

typedef struct WindowElement {
 WindowPeek theWindowPtr;
 GDHandle theDevHndl;
} WindowElement, *WindowElementPtr;

typedef Boolean (*TileStackWindowsProc)
 (Rect *enclosingRectPtr,
 WindowElementPtr p, int wCount);
 
 
/*****************************************************
 * prototypes
 ****************************************************/
 
void  TileStackWindows(TileStackWindowsProc
 theTileStackProc);
Boolean MyMoveWindow(WindowPtr w, int leftGlobal,
 int topGlobal, Boolean sizeChanged);
Boolean MySizeWindow(WindowPtr w, int width,
 int height);
TileStackWindows.c Listing
/*****************************************************
 * TileStackWindows.c
 *
 * Set of routines to quickly rearrange windows
 * on multiple devices.
 *
 * Mike Scanlin  10 July 1993
 ****************************************************/

#include <GestaltEqu.h>
#include <Traps.h>
#include "TileStackWindows.h"

/*****************************************************
 * defines
 ****************************************************/

#define BAD_DEVICE ((GDHandle) -1)
#define TOPLEFT_SLOP 2
#define BOTRIGHT_SLOP3
#define NIL 0L

/* MAX_WINDOWS is not a real limit but stack space
 * requirements for TileStackWindows are equal to
 * (sizeof(WindowElement) * 2 * MAX_WINDOWS) so
 * don't make it too big. It's the max number of
 * windows that TileStackWindows can deal with.
 */
#define MAX_WINDOWS100

/*****************************************************
 * typedefs
 ****************************************************/

typedef pascal long(**WDefProcHndl)(int var,
 WindowPtr w, int message, long param);

/*****************************************************
 * prototypes
 ****************************************************/
 
static GDHandle DominantDevice(Rect *theRect);

/*****************************************************
 * TileStackWindows
 *
 * Calls theTileStackProc on a per-device basis to
 * clean up (stack, tile or whatever else you can
 * think of) all the windows on that device. Once
 * all devices have been taken care of the part of
 * the screen that needs to be updated is updated.
 ****************************************************/
void TileStackWindows(TileStackWindowsProc
 theTileStackProc)
{
 WindowElementPtrp, dp;
 WindowPeek w;
 GDHandle deviceHndl;
 RgnHandle  sumOfStructRgns;
 WindowElement   theWindows[MAX_WINDOWS],
 theDeviceWindows[MAX_WINDOWS];
 long   theQDVers;
 Rect   enclosingRect;
 int    i, totalWindows,
 windowsToClean,
 deviceWindows;
 BooleanneedToRedraw, hasColorQD;
 
 /* check for color QuickDraw */
 hasColorQD = FALSE;
 if (TrapIsAvailable(_Gestalt)) {
 Gestalt(gestaltQuickdrawVersion, &theQDVers);
 hasColorQD = theQDVers >= 0x0100;
 }

 sumOfStructRgns = NewRgn();
 needToRedraw = FALSE;
 
 /* find the dominant device for each window
  * as we add it to our list of windows
  */
 p = theWindows;
 totalWindows = 0;
 w = (WindowPeek) FrontWindow();
 while (w != NIL && totalWindows < MAX_WINDOWS) {
 p->theWindowPtr = w;
 p->theDevHndl = NIL;
 if (hasColorQD)
 p->theDevHndl =
   DominantDevice(&(*w->strucRgn)->rgnBBox);
 p++;
 totalWindows++;
 /* or the old struct region into the
  * update region
  */
 UnionRgn(sumOfStructRgns, w->strucRgn,
 sumOfStructRgns);
 w = w->nextWindow;
 }
 
 if (totalWindows == 0)
 goto Exit;
 
 /* set up enclosingRect here in case we don't
  * have color QD; if we do have colorQD then
  * enclosingRect is set again in the loop below
  * on a per-device basis
  */
 enclosingRect = (*GetGrayRgn())->rgnBBox;
 enclosingRect.top += TOPLEFT_SLOP;
 enclosingRect.left += TOPLEFT_SLOP;
 enclosingRect.bottom -= BOTRIGHT_SLOP;
 enclosingRect.right -= BOTRIGHT_SLOP;

 windowsToClean = totalWindows;
 do {
 /* find the first device in the list that we
  * haven't already done and copy all elements
  * from that device into a new list
  */
 p = theWindows;
 dp = theDeviceWindows;
 deviceWindows = 0;
 deviceHndl = BAD_DEVICE;
 i = totalWindows;
 do {
 if (p->theDevHndl != BAD_DEVICE) {
 if (deviceHndl == BAD_DEVICE) {
 /* this is the first time we've
  * seen this device so we do a
  * little set up first
  */
 deviceHndl = p->theDevHndl;
 /* if we have colorQD, use the
  * device's rect
  */
 if (deviceHndl != NIL) {
 enclosingRect = (*deviceHndl)->gdRect;
 enclosingRect.top += TOPLEFT_SLOP;
 enclosingRect.left += TOPLEFT_SLOP;
 enclosingRect.bottom -= BOTRIGHT_SLOP;
 enclosingRect.right -= BOTRIGHT_SLOP;
 if (deviceHndl == GetMainDevice())
 enclosingRect.top += GetMBarHeight();
 }
 }
 if (deviceHndl == p->theDevHndl) {
 /* it's on the current device,
  * add it to the list
  */
 *dp++ = *p;
 deviceWindows++;
 /* we don't want to see this
  * one again
  */
 p->theDevHndl = BAD_DEVICE;
 }
 }
 p++;
 } while (--i);
 
 if (deviceWindows > 0) {
 /* do something to the windows on
  * this device
  */
 needToRedraw |= (*theTileStackProc)
   (&enclosingRect, theDeviceWindows,
   deviceWindows);
 windowsToClean -= deviceWindows;
 }
 
 } while (windowsToClean > 0);
 
 if (needToRedraw) {
 
 /* add all of the new struct regions to the
  * update region
  */
 p = theWindows;
 do {
 UnionRgn(sumOfStructRgns,
   p->theWindowPtr->strucRgn,
   sumOfStructRgns);
 p++;
 } while (--totalWindows);
 
 /* To see a cool effect, trap on the next
  * instruction and watch the screen as you
  * step over it. All window frames are drawn
  * with this one call to the ROMs.
  */
 PaintBehind(theWindows[0].theWindowPtr,
   sumOfStructRgns);
 
 /* Need to reset the visRgns since
  * MySizeWindow nuked 'em.
  */
 CalcVisBehind(theWindows[0].theWindowPtr,
   sumOfStructRgns);
 }

Exit:

 DisposeRgn(sumOfStructRgns);
}


/*****************************************************
 * DominantDevice
 *
 * This returns a device hndl to the device that
 * owns most of the given Rect (which is in global
 * coordinates). This routine requires ColorQD.
 ****************************************************/
static GDHandle DominantDevice(Rect *theRect)
{
 GDHandle nthDevice, theDevice;
 long   greatestArea, sectArea;
 Rect   theSect;
 
 nthDevice = theDevice = GetDeviceList();
 greatestArea = 0;
 do {
 if (TestDeviceAttribute(nthDevice, screenDevice) &&
   TestDeviceAttribute(nthDevice, screenActive)) {
 SectRect(theRect, &(*nthDevice)->gdRect,
   &theSect);
 sectArea =
   ((long) (theSect.bottom - theSect.top)) *
   ((long) (theSect.right - theSect.left));
 if (sectArea > greatestArea) {
 greatestArea = sectArea;
 theDevice = nthDevice;
 }
 }
 nthDevice = GetNextDevice(nthDevice);
 } while (nthDevice != NIL);
 
 return (theDevice);
}


/*****************************************************
 * MyMoveWindow
 *
 * Quickly move the window. No screen updating
 * will take place.
 ****************************************************/
Boolean MyMoveWindow(WindowPtr w, int leftGlobal,
 int topGlobal, Boolean sizeChanged)
{
 Handle theDefProc;
 GrafPtroldPort;
 Point  upperLeft;
 char   oldState;
 BooleanitMoved;
 
 itMoved = FALSE;

 oldPort = thePort;
 SetPort(w);
 
 /* Don't move it if it's already there, unless
  * it was just resized (in which case we don't
  * really need to call MovePortTo but we do
  * need to call the windowDefProc below to fix
  * up the regions).
  */
 if (!sizeChanged) {
 upperLeft = topLeft(w->portRect);
 LocalToGlobal(&upperLeft);
 if (upperLeft.h == leftGlobal &&
   upperLeft.v == topGlobal)
 goto Exit;
 }
 
 itMoved = TRUE;
 
 MovePortTo(leftGlobal, topGlobal);
 
 theDefProc = ((WindowPeek) w)->windowDefProc;
 oldState = HGetState(theDefProc);
 HLock(theDefProc);
 
 /* call the WDEF to update the regions */
 (*(WDefProcHndl) theDefProc)(zoomDocProc, w,
   wCalcRgns, 0);

 HSetState(theDefProc, oldState);

Exit:

 SetPort(oldPort);
 
 return (itMoved);
}


/*****************************************************
 * MySizeWindow
 *
 * Quickly set the size of a window. Set the
 * visRgn to NIL so that no screen updating takes
 * place. The visRgn will be reset when we call
 * CalcVisBehind later.
 ****************************************************/
Boolean MySizeWindow(WindowPtr w, int width,
 int height)
{
 GrafPtroldPort;
 
 /* don't size it if it's already the right size */
 if (w->portRect.right - w->portRect.left == width &&
   w->portRect.bottom - w->portRect.top == height)
   return(FALSE);
   
 oldPort = thePort;
 SetPort(w);
 
 PortSize(width, height);
 
 /* nuke the visRgn so that moving this port
  * (in MyMoveWindow) won't cause any screen
  * drawing
  */
 SetEmptyRgn(((GrafPtr) w)->visRgn);
 
 SetPort(oldPort);
 
 return(TRUE);
}
test.c Listing
/*****************************************************
 * test.c
 *
 * Driver function and example TileStackWindows
 * function to test out TileStackWindows.
 ****************************************************/

#include "TileStackWindows.h"

/*****************************************************
 * defines
 ****************************************************/

#define NUM_TEST_WINDOWS  20

/*****************************************************
 * prototypes
 ****************************************************/
 
static Boolean StackWindows(Rect *enclosingRectPtr,
 WindowElementPtr p, int wCount);

/*****************************************************
 * main
 ****************************************************/
void main()
{
 WindowPtr*p, windowPtrArray[NUM_TEST_WINDOWS];
 Rect   theBounds;
 int    i;
 
 theBounds.top = 50;
 theBounds.left = 50;
 theBounds.bottom = 200;
 theBounds.right = 200;
 
 p = windowPtrArray;
 i = NUM_TEST_WINDOWS;
 do {
 *p++ = NewWindow(0L, &theBounds, "\pTest",
 TRUE, 0, (WindowPtr) -1, TRUE, 0);
 OffsetRect(&theBounds, 3, 2);
 } while (--i);
 
 TileStackWindows(StackWindows);
}


/* window stacking variables used by StackWindows */
#define WTitleHeight 18
#define StaggerH 7
#define StaggerV (WTitleHeight - 2)
#define MinVertSize200
#define NextRowOffsetH    2
#define NextRowOffsetV    4

/*****************************************************
 * StackWindows -- example TileStackWindows proc
 *
 * Stack all the windows so you can see their
 * titles. Returns TRUE if we moved or sized at
 * least one window (if not then we don't need to
 * redraw the screen).
 ****************************************************/
static Boolean StackWindows(enclosingRectPtr, p, wCount)
Rect    *enclosingRectPtr;
WindowElementPtr p;
intwCount;
{
 WindowPtrw;
 Rect   theBounds;
 Point  upperLeft;
 int    width;
 BooleandidOne, sizeChanged;
 
 theBounds = *enclosingRectPtr;
 theBounds.top += WTitleHeight;
 upperLeft = topLeft(theBounds);
 width = theBounds.right - theBounds.left;
 
 didOne = FALSE;
 
 /* this particular routine starts at the back
  * of the list and works it's way forward
  * (to the frontmost window)
  */
 p += wCount;
 do {
 p--;
 w = (WindowPtr) p->theWindowPtr;
 sizeChanged = MySizeWindow(w,
 theBounds.right - theBounds.left,
 theBounds.bottom - theBounds.top);
 didOne |= sizeChanged;
 didOne |= MyMoveWindow(w, theBounds.left,
 theBounds.top, sizeChanged);
 theBounds.left += StaggerH;
 theBounds.right += StaggerH;
 theBounds.top += StaggerV;
 if (theBounds.top >
   enclosingRectPtr->bottom - MinVertSize) {
 upperLeft.h += NextRowOffsetH;
 upperLeft.v += NextRowOffsetV;
 topLeft(theBounds) = upperLeft;
 theBounds.right = theBounds.left + width;
 }
 if (theBounds.right > enclosingRectPtr->right)
 theBounds.right = enclosingRectPtr->right;
 } while (--wCount);
 
 return (didOne);
}

The Rules

Here’s how it works: Each month there will be a different programming challenge presented here. First, you must write some code that solves the challenge. Second, you must optimize your code (a lot). Then, submit your solution to MacTech Magazine (formerly MacTutor). A winner will be chosen based on code correctness, speed, size and elegance (in that order of importance) as well as the postmark of the answer. In the event of multiple equally desirable solutions, one winner will be chosen at random (with honorable mention, but no prize, given to the runners up). The prize for the best solution each month is $50 and a limited edition “The Winner! MacTech Magazine Programming Challenge” T-shirt (not to be found in stores).

In order to make fair comparisons between solutions, all solutions must be in ANSI compatible C (i.e., don’t use Think’s Object extensions). Only pure C code can be used. Any entries with any assembly in them will be disqualified (except for those challenges specifically stated to be in assembly). However, you may call any routine in the Macintosh toolbox you want (i.e., it doesn’t matter if you use NewPtr instead of malloc). All entries will be tested with the FPU and 68020 flags turned off in THINK C. When timing routines, the latest version of THINK C will be used (with ANSI Settings plus “Honor ‘register’ first” and “Use Global Optimizer” turned on) so beware if you optimize for a different C compiler. All code should be limited to 60 characters wide. This will aid us in dealing with e-mail gateways and page layout.

The solution and winners for this month’s Programmers’ Challenge will be published in the issue two months later. All submissions must be received by the 10th day of the month printed on the front of this issue.

All solutions should be marked “Attn: Programmers’ Challenge Solution” and sent to Xplain Corporation (the publishers of MacTech Magazine) via “snail mail” or preferably, e-mail - AppleLink: MT.PROGCHAL, Internet: progchallenge@xplain.com, CompuServe: 71552,174 and America Online: MT PRGCHAL. If you send via snail mail, please include a disk with the solution and all related files (including contact information). See page 2 for information on “How to Contact Xplain Corporation.”

MacTech Magazine reserves the right to publish any solution entered in the Programming Challenge of the Month and all entries are the property of MacTech Magazine upon submission. The submission falls under all the same conventions of an article submission.

 
AAPL
$102.50
Apple Inc.
+0.25
MSFT
$45.43
Microsoft Corpora
+0.55
GOOG
$571.60
Google Inc.
+2.40

MacTech Search:
Community Search:

Software Updates via MacUpdate

VueScan 9.4.41 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
Cloud 3.0.0 - File sharing from your men...
Cloud is simple file sharing for the Mac. Drag a file from your Mac to the CloudApp icon in the menubar and we take care of the rest. A link to the file will automatically be copied to your clipboard... Read more
LibreOffice 4.3.1.2 - Free Open Source o...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
SlingPlayer Plugin 3.3.20.505 - Browser...
SlingPlayer is the screen interface software that works hand-in-hand with the hardware inside the Slingbox to make your TV viewing experience just like that at home. It features an array of... Read more
Get Lyrical 3.8 - Auto-magically adds ly...
Get Lyrical auto-magically add lyrics to songs in iTunes. You can choose either a selection of tracks, or the current track. Or turn on "Active Tagging" to get lyrics for songs as you play them.... Read more
Viber 4.2.2 - Send messages and make cal...
Viber lets you send free messages and make free calls to other Viber users, on any device and network, in any country! Viber syncs your contacts, messages and call history with your mobile device,... Read more
Cocktail 7.6 - General maintenance and o...
Cocktail is a general purpose utility for OS X that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get... Read more
LaunchBar 6.1 - Powerful file/URL/email...
LaunchBar is an award-winning productivity utility that offers an amazingly intuitive and efficient way to search and access any kind of information stored on your computer or on the Web. It provides... Read more
Maya 2015 - Professional 3D modeling and...
Maya is an award-winning software and powerful, integrated 3D modeling, animation, visual effects, and rendering solution. Because Maya is based on an open architecture, all your work can be scripted... Read more
BBEdit 10.5.12 - Powerful text and HTML...
BBEdit is the leading professional HTML and text editor for the Mac. Specifically crafted in response to the needs of Web authors and software developers, this award-winning product provides a... Read more

Latest Forum Discussions

See All

Qube Kingdom – Tips, Tricks, Strategies,...
Qube Kingdom is a tower defense game from DeNA. You rally your troops – magicians, archers, knights, barbarians, and others – and fight against an evil menace looking to dominate your kingdom of tiny squares. Planning a war isn’t easy, so here are a... | Read more »
Qube Kingdom Review
Qube Kingdom Review By Nadia Oxford on August 29th, 2014 Our Rating: :: KIND OF A SQUARE KINGDOMUniversal App - Designed for iPhone and iPad Qube Kingdom has cute visuals, but it’s a pretty basic tower defense game at heart.   | Read more »
Fire in the Hole Review
Fire in the Hole Review By Rob Thomas on August 29th, 2014 Our Rating: :: WALK THE PLANKUniversal App - Designed for iPhone and iPad Seafoam’s Fire in the Hole looks like a bright, 8-bit throwback, but there’s not enough booty to... | Read more »
Alien Creeps TD is Now Available Worldwi...
Alien Creeps TD is Now Available Worldwide Posted by Ellis Spice on August 29th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Dodo Master Review
Dodo Master Review By Jordan Minor on August 29th, 2014 Our Rating: :: NEST EGGiPad Only App - Designed for the iPad Dodo Master is tough but fair, and that’s what makes it a joy to play.   | Read more »
Motorsport Manager Review
Motorsport Manager Review By Lee Hamlet on August 29th, 2014 Our Rating: :: MARVELOUS MANAGEMENTUniversal App - Designed for iPhone and iPad Despite its depth and sense of tactical freedom, Motorsport Manager is one of the most... | Read more »
Motorsport Manager – Beginner Tips, Tric...
The world of Motorsport management can be an unforgiving and merciless one, so to help with some of the stress that comes with running a successful race team, here are a few hints and tips to leave your opponents in the dust. | Read more »
CalPal Update Brings the App to 2.0, Add...
CalPal Update Brings the App to 2.0, Adds Lots of New Stuff Posted by Ellis Spice on August 29th, 2014 [ permalink ] | Read more »
Baseball Battle Review
Baseball Battle Review By Jennifer Allen on August 29th, 2014 Our Rating: :: SIMPLE HITTINGUniversal App - Designed for iPhone and iPad Simple and cute, Baseball Battle is a fairly fun baseball game for those looking for something... | Read more »
Checkmark 2.1 Update Released, and it’s...
Checkmark 2.1 Update Released, and it’s on Sale for a Limited Time Posted by Jessica Fisher on August 29th, 2014 [ permalink ] | Read more »

Price Scanner via MacPrices.net

Labor Day Weekend MacBook Pro sale; 15-inch m...
B&H Photo has the new 2014 15″ Retina MacBook Pros on sale for up to $125 off MSRP. Shipping is free, and B&H charges NY sales tax only. They’ll also include free copies of Parallels Desktop... Read more
Labor Day Weekend iPad mini sale; $50 to $100...
Best Buy has the iPad mini with Retina Display (WiFi models) on sale for $50 off MSRP on their online store for Labor Day Weekend. Choose free shipping or free local store pick up. Price is for... Read more
13-inch 1.4GHz MacBook Air on sale for $899,...
Adorama has the new 2014 13″ 1.4GHz/128GB MacBook Air on sale for $899.99 including free shipping plus NY & NJ tax only. Their price is $100 off MSRP. Read more
It’s Official: Apple Issues Invitations To Se...
Apple has issued one of its characteristically cryptic press invitations for a special event to be held at the Flint Center for the Performing Arts in hometown Cupertino on Sept. 9, 2014 at 10:00 am... Read more
Tablet Shipments To See First On-year Decline...
TrendForce analyst Caroline Chen notes that when the iPad launched in 2010, it was an instant hit and spurred a tablet PC revolution, with tablets so popular that that notebook PC sales stagnated and... Read more
SOBERLINK Releases Apple iOS Compatible Handh...
Cypress, California based SOBERLINK, Inc., creator of the first handheld Breathalyzer designed to improve recovery outcomes, continues to show prominence in the mobile alcohol monitoring space with... Read more
New 21″ 1.4GHz iMac on sale again for $999, s...
Best Buy has the new 21″ 1.4GHz iMac on sale for $999.99 on their online store. Their price is $100 off MSRP. Choose free shipping or free local store pick up. Price is for online orders only, in-... Read more
Smartphone Outlook Remains Strong for 2014, U...
According to a new mobile phone forecast from the International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker, more than 1.25 billion smartphones will be shipped worldwide in 2014,... Read more
Save up to $60 with Apple refurbished iPod to...
The Apple Store has Apple Certified Refurbished 5th generation iPod touches available starting at $149. Apple’s one-year warranty is included with each model, and shipping is free. Many, but not all... Read more
12-Inch MacBook Air Coming in 4Q14 or 2015 –...
Digitimes’ Aaron Lee and Joseph Tsai report that according to Taiwan-based upstream supply chain insiders, Apple plans to launch a thinner MacBook model either at year end 2014 or in 2015, and that... Read more

Jobs Board

*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* 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* 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* 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
Senior Event Manager, *Apple* Retail Market...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global event strategy. Delivering an overarching brand story; in-store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.