TweetFollow Us on Twitter

Sep 93 Tips, Tidbits
Volume Number:9
Issue Number:9
Column Tag:Tips & Tidbits

Related Into: Standard File Memory Manager

Tips & Tidbits

By Neil Ticktin, Editor-in-Chief

This column is your opportunity to spread the word about little bits of information that you find out about. These tidbits can be programming related or they can be user tips that are particularly useful to programmers.

MacTech Magazine will pay $25 for every tip used, and $50 for the Tip of the Month. Or you can take your award in orders or subscriptions.

To submit a tip, send in a letter to the magazine. E-mail is our preferred method, but feel free to send something via the US Mail. See page two for all addresses. If you do send snail mail, enclose a printed copy and a disk copy of the letter so that it does not have to be retyped.

Tip of the Month

The toolbox call BlockMove is quite efficient and smart, especially for large chunks of data. In moving smaller pieces of memory, a very simple macro can do as well and execute much faster:

/* 1 (/
#define BLOCKMOVE(source,dest,len) \
{ typedef struct { char s[len] ; } _sss ;  \
  *(_sss*) (dest) = *(_sss*) (source) ;\
}

This macro generates a temporary structure of size 'len', and assigns the source structure to the destination structure. In this case the compiler will generate a tight loop moving 2 or 4 bytes of data whenever possible. There is no space penalty, i.e., it compiles to exactly the same number of bytes as a normal BlockMove.

Two restrictions apply in using BLOCKMOVE:

• the parameter 'len' must be a constant.

• the source and destinations cannot overlap.

Some performance comparisons:

Bytes BlockMove memcpy BLOCKMOVE

50 9 9 2

100 11 15 4

150 12 21 7

200 14 28 8

250 15 34 11

300 17 41 13

350 18 49 14

400 20 55 16

450 21 61 19

500 22 68 21

These comparisons were done on a PowerBook Duo 230 using Think C 6.0. Times are all measured in ticks for 5000 samples.

- Jan Bruyndonckx, Wave Research, Belgium

[If you are interested in more information on BlockMove, you might want to check out an article by Mike Scanlin in the May, 1993 issue of MacTech Magazine. The article is about writing a more efficient 68040 BlockMove. - Ed.]

Dump obj formatter

The MPW command 'dumpobj SomeLibrary > LibraryObjectCode.a' disassembles compiled library code into the form:

Module: Flags=$00=(Local Code) Module="SomeProcedure"(8) Segment="Main"(7)

Reference: Flags=$90=(A5Relative 16BitPatch 16BitOffsets FromCode)

Ref="arrow"(12)

0006

Content: Flags $08

Contents offset $0000 size $003A

00000000: 4E56 FFFC 'NV..' LINK A6,#$FFFC

00000004: 4AAE 0008 'J...' TST.L $0008(A6)

00000008: 6606 'f.' BNE.S *+$0008 ;00000010

The script below modifies the disassembled code into the form:

Module="SomeProcedure"(8) Segment="Main"(7)
 LINK   A6,#$FFFC
 TST.L  $0008(A6)
 BNE.S  *+$0008

The script:

          #2
format -f geneva -s 9 -t 26  #Set font, font size, tab size

#STEP1 - removes code comments 
find •
Loop
  #Find ; preceded by spaces & select to
  #  the end of line
find /" "+;/:/ /
  #Replace selection with nothing
replace § ""
End

#STEP2 - removes routine text header
find •
Loop
#Selects all lines between Reference &
#  second word Content
#end of line to the.
find /Reference/:/Content/:/Content/:/ /
replace § ""#Replace selection with nothing
End

#STEP3 - Delete everything before exprssn
#"Module="
find •
Loop
#Select everything in front of
#Module= to the beginning of the line
find /"Module="/:\•\
replace § ""#Replace with nothing
find !1 #Select next line
End

#STEP4 - Formats instruction lines
find •
Loop
#Find the line that starts with 4 0's
find /"0000"????/
 #followed by any 4 characters.
find /?«43»/#Select 43 characters from beginning of line
replace § "t"   #Replace selection w/tab
#Select spaces between Opcode and operand
find /" "+/ 
replace § "t"   #Replace with a tab
End#Repeat the Loop until done

In MPW, make the window that contains your disassemble routine the target window - click on it and then click back to the window that contains the above script. Select the lines under each step separately and hit the "Enter" key. Your code should align nicely into the format shown above.

- Greg Pribyl, Incline Village, NV

Customgetfile customization

I recently had to customize a CustomGetFile dialog to select folders. The returned StandardFileReply record contains the file specificatins of the target folder. But I needed to create files inside that folder while the directory ID in the specifications refers to its parent directory.

A simple method for getting a FSSpec record having as parID the directory ID of the selected folder, thus allowing to put the name of the new file into FSSpec.name without further actions, uses FSMakeFSSpec, documented in Inside Macintosh VI (25-30):

FUNCTION FSMakeFSSpec  (vRefNum:Integer;  dirID: LongInt; fileName: Str255; 
VAR spec: FSSpec): OSErr;

The first two parameters will be the same as in the file specifications of the target folder while fileName will contain a partial path.

/* 3 */

function  FileInFolderSpec (theSpec: 
 FSSpec): FSSpec;
var
 target:  FSSpec;
 fn: Str255;
 error:  OSErr;
begin
{theSpec: folder specifications}
 fn:=Concat(':' ,theSpec.name,': ');

 {create a partial path}
 error:=FSMakeFSSpec(theSpec.vRefNum,
 theSpec.parID, fn, target);
 FileInFolderSpec:= target;
end;

A fnfErr (file or directory does not exist) error will be returned because the partial path was incomplete, ending with ':' instead of a filename, but target is nonetheless valid.

- Luigi Belverato, Milano, Italy

 
AAPL
$95.60
Apple Inc.
-2.55
MSFT
$43.16
Microsoft Corpora
-0.42
GOOG
$571.60
Google Inc.
-15.82

MacTech Search:
Community Search:

Software Updates via MacUpdate

OneNote 15.2 - Free digital notebook fro...
OneNote is your very own digital notebook. With OneNote, you can capture that flash of genius, that moment of inspiration, or that list of errands that’s too important to forget. Whether you’re at... Read more
iStat Menus 4.22 - Monitor your system r...
iStat Menus lets you monitor your system right from the menubar. Included are 8 menu extras that let you monitor every aspect of your system. Some features: CPU -- Monitor cpu usage. 7 display... Read more
Ember 1.8 - Versatile digital scrapbook....
Ember (formerly LittleSnapper) is your digital scrapbook of things that inspire you: websites, photos, apps or other things. Just drag in images that you want to keep, organize them into relevant... Read more
OmniPlan 2.3.6 - Robust project manageme...
With OmniPlan, you can create logical, manageable project plans with Gantt charts, schedules, summaries, milestones, and critical paths. Break down the tasks needed to make your project a success,... Read more
Command-C 1.1.1 - Clipboard sharing tool...
Command-C is a revolutionary app which makes easy to share your clipboard between iOS and OS X using your local WiFi network, even if the app is not currently opened. Copy anything (text, pictures,... Read more
Knock 1.1.7 - Unlock your Mac by knockin...
Knock is a faster, safer way to sign in. You keep your iPhone with you all the time. Now you can use it as a password. You never have to open the app -- just knock on your phone twice, even when it's... Read more
Mellel 3.3.6 - Powerful word processor w...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
LibreOffice 4.3.0.4 - 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
Freeway Pro 7.0 - Drag-and-drop Web desi...
Freeway Pro lets you build websites with speed and precision... without writing a line of code! With it's user-oriented drag-and-drop interface, Freeway Pro helps you piece together the website of... Read more
Drive Genius 3.2.4 - Powerful system uti...
Drive Genius is an OS X utility designed to provide unsurpassed storage management. Featuring an easy-to-use interface, Drive Genius is packed with powerful tools such as a drive optimizer, a... Read more

Latest Forum Discussions

See All

Dawn of the Immortals Review
Dawn of the Immortals Review By Jennifer Allen on July 31st, 2014 Our Rating: :: RESPECTABLE EXPLORATIONUniversal App - Designed for iPhone and iPad Dawn of the Immortals might not re-invent the wheel, but it does tweak it a little... | Read more »
80 Days Review
80 Days Review By Jennifer Allen on July 31st, 2014 Our Rating: :: EPIC ADVENTUREUniversal App - Designed for iPhone and iPad A fantastic and fascinating re-envisioning of the classic novel by Jules Verne, 80 Days is a delightful... | Read more »
Battleheart Legacy Guide
The world of Battleheart Legacy is fun and deep; full of wizards, warriors, and witches. Here are some tips and tactics to help you get the most enjoyment out of this great game. | Read more »
Puzzle Roo Review
Puzzle Roo Review By Jennifer Allen on July 31st, 2014 Our Rating: :: PUZZLE-BASED TWISTUniversal App - Designed for iPhone and iPad A different take on the usual block dropping puzzle game, Puzzle Roo is quite pleasant.   | Read more »
Super Crossfire Re-Release Super Crossfi...
Super Crossfire Re-Release Super Crossfighter Coming Soon, Other Radiangames Titles Go 50% Off Posted by Ellis Spice on July 31st, 2014 [ | Read more »
Hexiled Review
Hexiled Review By Rob Thomas on July 31st, 2014 Our Rating: :: HEX SELLSUniversal App - Designed for iPhone and iPad In space, no one can hear you… spell? Hexiled is a neat concept for a word scramble puzzle, but it doesn’t go too... | Read more »
Summoners War: Sky Arena Passes 10 Milli...
Summoners War: Sky Arena Passes 10 Million Installs! Posted by Jessica Fisher on July 31st, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Deep Loot Review
Deep Loot Review By Jennifer Allen on July 31st, 2014 Our Rating: :: DIVE DEEPUniversal App - Designed for iPhone and iPad Dive deep in this fun explore-em-up that’s a little grind heavy but ultimately quite entertaining.   | Read more »
Despicable Me: Minion Rush is One Year O...
Despicable Me: Minion Rush is One Year Old, Gets its Biggest Update Yet Posted by Jennifer Allen on July 31st, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Fish & Shark Review
Fish & Shark Review By Jordan Minor on July 31st, 2014 Our Rating: :: FLAPPY FISHUniversal App - Designed for iPhone and iPad Fish & Shark’s beauty is only scale deep.   | Read more »

Price Scanner via MacPrices.net

Save up to $130 on an iPad mini with Apple re...
The Apple Store has Certified Refurbished 2nd generation iPad minis with Retina Displays available for up to $130 off the cost of new models, starting at $339. Apple’s one-year warranty is included... Read more
iPad Cannibalization Threat “Overblown”
Seeking Alpha’s Kevin Greenhalgh observes that while many commentators think Apple’s forthcoming 5.5-inch panel iPhone 6 will cannibalize iPad sales, in his estimation, these concerns are being... Read more
Primate Labs Releases July 2014 MacBook Pro P...
Primate Labs’ John Poole has posted Geekbench 3 results for most of the new MacBook Pro models that Apple released on Tuesday. Poole observes that overall performance improvements for the new MacBook... Read more
Apple Re-Releases Bugfixed MacBook Air EFI Fi...
Apple has posted a bugfixed version EFI Firmware Update 2.9 a for MacBook Air (Mid 2011) models. The update addresses an issue where systems may take longer to wake from sleep than expected, and... Read more
Save $50 on the 2.5GHz Mac mini, plus free sh...
B&H Photo has the 2.5GHz Mac mini on sale for $549.99 including free shipping. That’s $50 off MSRP, and B&H will also include a free copy of Parallels Desktop software. NY sales tax only. Read more
Save up to $140 on an iPad Air with Apple ref...
Apple is offering Certified Refurbished iPad Airs for up to $140 off MSRP. Apple’s one-year warranty is included with each model, and shipping is free. Stock tends to come and go with some of these... Read more
$250 price drop on leftover 15-inch Retina Ma...
B&H Photo has dropped prices on 2013 15″ Retina MacBook Pros by $250 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.3GHz Retina MacBook Pro: $2249, $250 off... Read more
More iPad Upgrade Musings – The ‘Book Mystiqu...
Much discussed recently, what with Apple reporting iPad sales shrinkage over two consecutive quarters, is that it had apparently been widely assumed that tablet users would follow a two-year hardware... Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
Best Buy has the 13″ 2.5GHz MacBook Pro available for $999.99 on their online store. Choose free shipping or free instant local store pickup (if available). Their price is $100 off MSRP. Price is... Read more
Save up to $300 on an iMac with Apple refurbi...
The Apple Store has Apple Certified Refurbished iMacs available for up to $300 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free. These are the best prices on... 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
Sr. Product Leader, *Apple* Store Apps - Ap...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full Read more
Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.