TweetFollow Us on Twitter

Apr 95 Tips
Volume Number:11
Issue Number:4
Column Tag:Tips & Tidbits

Tips & Tidbits

By Scott T Boyd, Editor

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

TIP OF THE MONTH

Doing Passwords the Simple Way

A common problem for people writing multi-user software for the Mac is the need to have a username/password dialog which allows the user to type the password without actually printing the real characters. Apple’s inimitable Tim Dierks released a snippet appropriately entitled “Password” which shows how to accomplish this in a variety of ways, most of which involve keeping one buffer which holds what the user actually types and another which contains the ‘display’ text (usually a line of bullets).

The following snippet shows how to accomplish this by replacing the QuickDraw bottlenecks. The beauty of this approach is that there is no messy buffer-update code needed for handling Cut/Copy/Paste, and text selection with the mouse is handled correctly. You may, however, want to prevent people from cutting or copying text to the clipboard, since if that text is pasted into any other TextEdit area it will display the password in normal text.

#ifdef __cplusplus
extern "C" { 
#endif

PasswordDrawProc
        void    PasswordDrawProc (void)
        {
                Ptr textBuff;
                short byteOff;
                short byteCnt, i;

                // load the correct parameters
                asm     {       move.l  A0, textBuff
                                move.w  D0, byteOff
                                move.w  D1, byteCnt
                        }
                for (i = 1; i <= byteCnt; i++)
                  DrawChar ('•');
        }
PasswordMeasureProc 
        void    PasswordMeasureProc (void)
        {
                short   textLen, offset;
                Ptr     textBuffer;
                short   width;
                
                // load the correct parameters
                asm     {       move.w  D0, textLen
                                move.w  D1, offset
                                move.l  A0, textBuffer
                        }
                width = CharWidth('•') * textLen;
                
                // return the width of the text
                asm     {       move.w  width, D1       }
        }

        TEHandle MakePasswordTextBox (void)
        {
                Rect     viewRect, destRect;
                TEHandle textBlock = NULL;
                
                SetRect (&viewRect, 15, 15, 165, 31);
                SetRect (&destRect, 15, 15, 165, 31);
                textBlock = TENew (&destRect, &viewRect);
                
                if (textBlock)
                  {
                   TECustomHook (intDrawHook,
                     (ProcPtr)PasswordDrawProc, textBlock);
                   TECustomHook (intWidthHook, 
                     (ProcPtr)PasswordMeasureProc, textBlock);
                  }
                return textBlock;
        }
#ifdef __cplusplus 
} 
#endif

- Eric Rosé, rose@nomos.com

SyncWait No More!

Sometimes when you’re AppleTalking or modeming and something goes wrong (like you switch the modem off while data is being sent to it), the computer will hang. The mouse will still move, but clicking will have no effect. Here’s the solution: Drop into MacsBug. You should see the routine name “_vSyncWait” plus something as the current location. If you don’t, you probably hit the system while it was doing something else. Hit Command-G to get back out of MacsBug, and try again. After a few tries you should find _vSyncWait.

_vSyncWait is the routine that the system uses to wait for some input from a serial port. If you can read assembly code, you’ll see that it’s pretty simple. Here’s the dump of the significant part:

+0000  4080BB8C   MOVE.W $0010(A0),D0              | 3028 0010      +0004 
 4080BB90   BGT.S  _vSyncWait   ; 4080BB8C   | 6EFA

Register A0 is pointing to a system data structure, in which a word will be cleared when the awaited input arrives. The MOVE.W instruction grabs this word and puts it into register D0. The BGT.S instruction then Branches back to the MOVE.W if the byte it just fetched is Greater Than zero (hence BGT). So it happens that this byte is never going to arrive for whatever reason, but the computer is going to wait for eternity. The secret to fixing this is to use Command-T to go step along until the MOVE.W instruction is displayed as the current instruction. Now use the “sw” command to set “@(a0+10)” to zero: sw @(a0+10) 0

Then hit Command-T twice more. The MOVE.W instruction will take the zero you just set into memory and put it in D0, so the D0 display on the right of the screen should have its right four digits all zeros. Then when you execute the BGT.S instruction, it should not go back to the MOVE.W since zero is not greater than zero.

Hit Command-G to go. If this was the only byte the software was waiting for, then it should continue running, although it may go a little crazy because it’s been suddenly disconnected from whatever peripheral it was talking to. Quit the program, fix your hardware, and try again.

- Macneil Shonle and Dustin Mitchell
MacneilS@aol.com and DustyM2@aol.com

So Easy To Forget These Things

I asked the question recently, “When debugging using Think C, after hitting the programmer’s switch and landing in MacsBug, how do I get back up to Think C’s source level debugger?”

The answer, while less than what I was looking for, was nonetheless useful. Think C’s debugger polls for Option-Command-Shift-Period. Use that instead of the programmer’s switch and you will be able to break into the debugger as long as the program is stuck in your own code, and not in the operating system somewhere.

- Jeffrey A. Lomicka, Marlboro MA, lomickaj@prnsys.enet.dec.com

What’ll They Call The Next One? Post-Modern Memory Manager?

So you’re trying to figure out whether a zone is a Modern Memory Manager zone? Why? Oh, never mind, you’ve certainly got a good reason (you do, don’t you?), so here’s how:

#define IsNewStyleZone(z)        \
              ((z)->heapType & 0x02)

if (IsNewStyleZone(LMGetSysZone()) {
   ...whatever...

- Dave Falkenburg, Apple

 
AAPL
$94.72
Apple Inc.
+0.78
MSFT
$44.83
Microsoft Corpora
-0.01
GOOG
$594.74
Google Inc.
+5.27

MacTech Search:
Community Search:

Software Updates via MacUpdate

Macs Fan Control 1.1.12 - Monitor and co...
Macs Fan Control allows you to monitor and control almost any aspect of your computer's fans, with support for controlling fan speed, temperature sensors pane, menu-bar icon, and autostart with... Read more
A Better Finder Rename 9.37 - File, phot...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more
MacBook Air EFI Firmware Update 2.9 - Fo...
MacBook Air EFI Firmware Update is recommended for MacBook Air (Mid 2011) models. This update addresses an issue where systems may take longer to wake from sleep than expected and fixes a rare issue... Read more
FileZilla 3.9.0.1 - Fast and reliable FT...
FileZilla (ported from Windows) is a fast and reliable FTP client and server with lots of useful features and an intuitive interface.Version 3.9.0.1: MSW: Fix installation issue with locked DLLs... Read more
OS X Yosemite 10.10 DP4 - Developer Prev...
Note: This is a Developer Preview. You must be a registered Apple Mac Developer to download this update. OS X Yosemite is Apple's newest operating system for Mac. An elegant design that feels... Read more
FinderPop 2.5.6 - Classic Mac utility, n...
FinderPop is a Universal preference pane that extends OS X's contextual menus using a FinderPop Items folder much as the Apple Menu Items folder used to do for the Apple menu. It has other features... Read more
SpiderOak 5.1.7 - Secure cloud backup, s...
SpiderOak is a multi-platform secure online backup, storage, access, and sharing solution engineered for the consumer and small businesses. You must first sign up to use SpiderOak. Running natively... Read more
Espionage 3.6 - Simple, state of the art...
Espionage offers state-of-the-art encryption and plausible deniability for your confidential data. Sometimes, encrypting your data isn't enough to protect it. That's why Espionage 3 goes beyond data... Read more
calibre 1.45.0 - Complete e-library mana...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital... Read more
iFFmpeg 4.3.1 - Convert multimedia files...
iFFmpeg is a graphical front-end for FFmpeg, a command-line tool used to convert multimedia files between formats. The command line instructions can be very hard to master/understand, so iFFmpeg does... Read more

Latest Forum Discussions

See All

Celebrate Summer With a Cat in the Hat L...
Celebrate Summer With a Cat in the Hat Learning Library Sale Posted by Ellis Spice on July 22nd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
MyTaskList Review
MyTaskList Review By Jennifer Allen on July 22nd, 2014 Our Rating: :: EFFECTIVE IF PLAINUniversal App - Designed for iPhone and iPad It’s not the most stylish of task management apps, but MyTaskList has all the features you could... | Read more »
FlyCraft Herbie: Crazy Machines Review
FlyCraft Herbie: Crazy Machines Review By Jennifer Allen on July 22nd, 2014 Our Rating: :: TRICKY FLYINGUniversal App - Designed for iPhone and iPad A tough game of careful thrusting and navigation, FlyCraft Herbie: Crazy Machines... | Read more »
MTN Review
MTN Review By Jessica Fisher on July 22nd, 2014 Our Rating: :: ADORABLE, SERENE, AND AMUSINGUniversal App - Designed for iPhone and iPad MTN is an adorable, talking pet mountain that is less game and more zen garden.   | Read more »
Fly High with Ninja UP! Now Available o...
Fly High with Ninja UP! Now Available on the App Store Posted by Jessica Fisher on July 22nd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Bio Inc. Review
Bio Inc. Review By Nadia Oxford on July 22nd, 2014 Our Rating: :: SICKENING - IN A COMPELLING WAYUniversal App - Designed for iPhone and iPad Bio Inc is about orchestrating the medical destruction of a single person. If that doesn’... | Read more »
HELMUT Review
HELMUT Review By Andrew Fisher on July 21st, 2014 Our Rating: :: TRUNDLE SIMULATOR 2014Universal App - Designed for iPhone and iPad HELMUT is a fun, fleeting time-sink that offers a momentary distraction and nothing else.   | Read more »
Walkr Review
Walkr Review By Jennifer Allen on July 21st, 2014 Our Rating: :: ORIGINAL WALKINGiPhone App - Designed for the iPhone, compatible with the iPad Walking is a bit more exciting thanks to this planet building/discovering sim reliant... | Read more »
Zombie Commando Review
Zombie Commando Review By Jennifer Allen on July 21st, 2014 Our Rating: :: MINDLESS SLAUGHTERUniversal App - Designed for iPhone and iPad Briefly fun but ultimately forgettable, Zombie Commando will scratch an itch then be... | Read more »
Swords & Poker Adventures Review
Swords & Poker Adventures Review By Jennifer Allen on July 21st, 2014 Our Rating: :: SOULLESS POKER PLAYUniversal App - Designed for iPhone and iPad Swords & Poker Adventures is a mishmash of Poker and RPGing, but it lacks... | Read more »

Price Scanner via MacPrices.net

15-inch 2.0GHz MacBook Pro Retina on sale for...
B&H Photo has the 15″ 2.0GHz Retina MacBook Pro on sale for $1829 including free shipping plus NY sales tax only. Their price is $170 off MSRP. B&H will also include free copies of Parallels... Read more
Apple restocks refurbished Mac minis for up t...
The Apple Store has restocked Apple Certified Refurbished Mac minis for up to $150 off the cost of new models. Apple’s one-year warranty is included with each mini, and shipping is free: - 2.5GHz Mac... Read more
Twelve South HiRise For MacBook – Height-Adju...
If you use your MacBook as a workhorse desktop substitute, as many of us do, a laptop stand combined with an external keyboard and pointing device are pretty much obligatory if you want to avoid... Read more
Why The Mac Was Not Included In The Apple/IBM...
TUAW’s Yoni Heisler cites Fredrick Paul of Network World whoi blogged last week that the Mac’s conspicuous absence from Apple and IBM’s landmark partnership agreement represents a huge squandered... Read more
Save $100 on 13-inch Retina MacBook Pros, plu...
Adorama has 13″ Retina MacBook Pros on sale for $100 off MSRP. Shipping is free, and Adorama charges sales tax in NY & NJ only: - 13″ 2.4GHz/128GB MacBook Pro with Retina Display: $1199 - 13″ 2.... Read more
Blurr it 2.3 for iOS – Quickly Blurs Selected...
Hyderabad, India based TouchLabs has announced a new update of Blurr it 2.3, their photography app for iOS users. Blurr it allows you to blur part of the image to hide potentially sensitive or... Read more
MacBook Airs on sale for $100 off MSRP, start...
Best Buy has the new 2014 MacBook Airs on sale for up to $100 off MSRP on their online store. Choose free home shipping or free local store pickup (if available). Prices valid for online orders only... Read more
Amazon Announces Kindle Unlimited: Unlimited...
Amazon.com has introduced Kindle Unlimited — a new subscription service which allows customers to freely read as much as they want from over 600,000 Kindle books, and listen as much as they want to... Read more
New Linksys Wireless Range Extenders Boost Wi...
Linksys has announced its new lineup of Linksys Wi-Fi Range Extenders. Consumers often experience a weak wireless signal in some parts of their house or apartment caused by blocking elements such as... Read more
MacBook Airs available starting at $719
The Apple Store has Apple Certified Refurbished 2013 & 2012 MacBook Airs in stock today starting at $719. An Apple one-year warranty is included with each MacBook, and shipping is free: 2013... Read more

Jobs Board

*Apple* Systems Administrator - DISH (United...
…satellite service provider, and Dish is currently looking for an experienced Apple /Mac Systems Administrator. Apple systems administrator will be responsible for Read more
*Apple* Systems Administrator - DISH (United...
…satellite service provider, and Dish is currently looking for an experienced Apple /Mac Systems Administrator. Apple systems administrator will be responsible for Read more
*Apple* /MAC Systems Administrator - Tekkies,...
Title: Apple /Mac Systems Administrator Location: Englewood, CO Term: Permanent Placement Description Our client is currently looking for an experienced Apple /Mac Read more
*Apple* Support Specialist - Expert Technica...
Apple Support Specialist Expert Technical has an immediate opening for an Apple Support Specialist with an industry leading creative and graphic arts company in Read more
Sales Director, GAM - *Apple* - AMD (United...
This position will be responsible for managing the Apple relationship with AMD. Ideally, the candidate has a good understanding of Apple 's products and Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.