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
$104.83
Apple Inc.
+1.84
MSFT
$45.02
Microsoft Corpora
+0.64
GOOG
$543.98
Google Inc.
+11.27

MacTech Search:
Community Search:

Software Updates via MacUpdate

Delicious Library 3.3.2 - Import, browse...
Delicious Library allows you to import, browse, and share all your books, movies, music, and video games with Delicious Library. Run your very own library from your home or office using our... Read more
Art Text 2.4.8 - Create high quality hea...
Art Text is an OS X application for creating high quality textual graphics, headings, logos, icons, Web site elements, and buttons. Thanks to multi-layer support, creating complex graphics is no... Read more
Live Interior 3D Pro 2.9.6 - Powerful an...
Live Interior 3D Pro is a powerful yet very intuitive interior designing application. View Video Tutorials It has every feature of Live Interior 3D Standard, plus some exclusive ones: Create multi... Read more
The Hit List 1.1.7 - Advanced reminder a...
The Hit List manages the daily chaos of your modern life. It's easy to learn - it's as easy as making lists. And it's powerful enough to let you plan, then forget, then act when the time is right.... Read more
jAlbum Pro 12.2.4 - Organize your digita...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code!... Read more
jAlbum 12.2.4 - Create custom photo gall...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results Simply drag and drop photos into groups, choose a design... Read more
ExpanDrive 4.1.7 - Access remote files o...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
OmniOutliner Pro 4.1.3 - Pro version of...
OmniOutliner Pro is a flexible program for creating, collecting, and organizing information. Give your creativity a kick start by using an application that's actually designed to help you think. It'... Read more
Evernote 5.6.2 - Create searchable notes...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
OmniOutliner 4.1.3 - Organize your ideas...
OmniOutliner is a flexible program for creating, collecting, and organizing information. Give your creativity a kick start by using an application that's actually designed to help you think. It's... Read more

Latest Forum Discussions

See All

Puzzle to the Center of the Earth Review
Puzzle to the Center of the Earth Review By Campbell Bird on October 23rd, 2014 Our Rating: :: SPELUNKING PUZZLESUniversal App - Designed for iPhone and iPad Do some puzzles to make some platforms in this smart and fun free-to-play... | Read more »
Sleep Attack TD Review
Sleep Attack TD Review By Jennifer Allen on October 23rd, 2014 Our Rating: :: A TRUE TWISTUniversal App - Designed for iPhone and iPad Sleep Attack TD is a tower defense game with a difference – you can rotate the layout – and it’s... | Read more »
Mecanic (Education)
Mecanic 1.0 Device: iOS Universal Category: Education Price: $1.99, Version: 1.0 (iTunes) Description: Plates, screws, wheels ... Everything you need to achieve whatever you want... MECHANICWith 'MECANIC' kids will have fun... | Read more »
Earn Your Master Camper Badge in Camp Po...
Earn Your Master Camper Badge in Camp Pokemon Posted by Jessica Fisher on October 23rd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Garruk Gets His Revenge in a New Magic 2...
Garruk Gets His Revenge in a New Magic 2015 Expansion, Coming This November Posted by Jessica Fisher on October 23rd, 2014 [ permalink ] | Read more »
Sentinels of the Multiverse Review
Sentinels of the Multiverse Review By Rob Thomas on October 23rd, 2014 Our Rating: :: SENTINELS ASSEMBLEiPad Only App - Designed for the iPad Greater Than Games’ tabletop classic, Sentinels of the Multiverse swoops in to save the... | Read more »
Build Your Own Fantasy Football Dynasty...
Build Your Own Fantasy Football Dynasty with Draft Day Posted by Jessica Fisher on October 23rd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Cars: Fast as Lightning – Tips, Tricks,...
Hey there, Stickers: Want to know all about how impressed we were with Radiator Springs? Check out our Cars: Fast as Lightning review! Cars: Fast as Lightning is a cute and fun app that combines racing and town-building with the charisma and... | Read more »
Jam Messenger Review
Jam Messenger Review By Jennifer Allen on October 23rd, 2014 Our Rating: :: SIMPLE MESSAGINGiPhone App - Designed for the iPhone, compatible with the iPad Want a very quick way to send push-based messages? Jam Messenger is basic... | Read more »
Felllice (Games)
Felllice 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: EXCLUSIVE PRICE DROP! 50% OFF FOR A LIMITED TIME! EAT EAT EAT AND GROW ! | Read more »

Price Scanner via MacPrices.net

Save up to $125 on Retina MacBook Pros
B&H Photo has the new 2014 13″ and 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... Read more
Apple refurbished Time Capsules available sta...
The Apple Store has certified refurbished Time Capsules available for up to $60 off MSRP. Apple’s one-year warranty is included with each Time Capsule, and shipping is free: - 2TB Time Capsule: $255... Read more
Textilus New Word, Notes and PDF Processor fo...
Textilus is new word-crunching, notes, and PDF processor designed exclusively for the iPad. I haven’t had time to thoroughly check it out yet, but it looks great and early reviews are positive.... Read more
WD My Passport Pro Bus-Powered Thunderbolt RA...
WD’s My Passport Pro RAID solution is powered by an integrated Thunderbolt cable for true portability and speeds as high as 233 MB/s. HighlightsOverviewSpecifications Transfer, Back Up And Edit In... Read more
Save with Best Buy’s College Student Deals
Take an additional $50 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through November 1st. Anyone with a valid .EDU email address can take advantage... Read more
iPad Air 2 & iPad mini 3 Best Tablets Yet...
The new iPads turned out to be pretty much everything I’d been hoping for and more than I’d expected.”More” particularly in terms of a drinking-from-a-firehose choice of models and configurations,... Read more
Drafts 4 Reinvents iOS Productivity App
N Richland Hills, Texas based Agile Tortoise has announced the release of Drafts 4 for iPhone and iPad. Drafts is a quick capture note taking app with flexible output actions. Drafts 4 scales from... Read more
AT&T accepting preorders for new iPads fo...
AT&T Wireless is accepting preorders for the new iPad Air 2 and iPad mini 3, cellular models, for $100 off MSRP with a 2-year service agreement: - 16GB iPad Air 2 WiFi + Cellular: $529.99 - 64GB... Read more
Apple offering refurbished Mac Pros for up to...
The Apple Store is offering Apple Certified Refurbished 2013 Mac Pros for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The... Read more
Select MacBook Airs $100 off MSRP, free shipp...
B&H Photo has 2014 a couple of MacBook Airs on sale for $100 off MSRP. Shipping is free, and B&H charges NY sales tax only. They also include free copies of Parallels Desktop and LoJack for... Read more

Jobs Board

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
*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
Project Manager / Business Analyst, WW *Appl...
…a senior project manager / business analyst to work within our Worldwide Apple Fulfillment Operations and the Business Process Re-engineering team. This role will work Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Position Opening at *Apple* - Apple (United...
…customers purchase our products, you're the one who helps them get more out of their new Apple technology. Your day in the Apple Store is filled with a range of Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.