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

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

SpamSieve 2.9.38 - Robust spam filter fo...
SpamSieve is a robust spam filter for major email clients that uses powerful Bayesian spam filtering. SpamSieve understands what your spam looks like in order to block it all, but also learns what... Read more
TeamViewer 15.0.8397 - Establish remote...
TeamViewer gives you remote control of any computer or Mac over the Internet within seconds or can be used for online meetings. Find out why more than 200 million users trust TeamViewer! Free for non... Read more
SteerMouse 5.4.3 - Powerful third-party...
SteerMouse is an advanced driver for USB and Bluetooth mice. SteerMouse can assign various functions to buttons that Apple's software does not allow, including double-clicks, modifier clicks,... Read more
Toast Titanium 18.2.1 - The ultimate med...
Roxio Toast Titanium, the leading DVD burner for Mac, makes burning even better, adding Roxio Secure Burn to protect your files on disc and USB in Mac- or Windows-compatible formats. Get more style... Read more
HoudahSpot 5.0.11 - Advanced file-search...
HoudahSpot is a versatile desktop search tool. Use HoudahSpot to locate hard-to-find files and keep frequently used files within reach. HoudahSpot will immediately feel familiar. It works just the... Read more
ClipGrab 3.8.6 - Download videos from Yo...
ClipGrab is a free downloader and converter for YouTube, Vimeo, Facebook and many other online video sites. It converts downloaded videos to MPEG4, MP3 or other formats in just one easy step Version... Read more
ExpanDrive 7.4.0 - Access cloud storage...
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
Adobe Dreamweaver CC 2020 20.0 - Build w...
Dreamweaver CC 2020 is available as part of Adobe Creative Cloud for as little as $20.99/month (or $9.99/month if you're a previous Dreamweaver customer). Adobe Dreamweaver CC 2020 allows you to... Read more
Eye Candy 7.2.3.85 - 30 professional Pho...
Eye Candy renders realistic effects that are difficult or impossible to achieve in Photoshop alone, such as Fire, Chrome, and the new Lightning. Effects like Animal Fur, Smoke, and Reptile Skin are... Read more
Sparkle Pro 2.8.5 - Visual website creat...
Sparkle Pro will change your mind if you thought building websites wasn't for you. Sparkle is the intuitive site builder that lets you create sites for your online portfolio, team or band pages, or... Read more

Latest Forum Discussions

See All

Pre-register for Hello Kitty AR: Kawaii...
Hello Kitty — the cute cat that launched a multi-billion-pound franchise — has been brought to life… sort of. Sanrio has teamed up with the Bublar Group to create a new mobile game that uses AR tech to turn the real world into Hello Kitty’s... | Read more »
Gorgeous and tranquil puzzler Spring Fal...
One-man indie studio SPARSE//GameDev has now launched its tranquil puzzler, Spring Falls. It's described as "a peaceful puzzle game about water, erosion, and watching things grow". [Read more] | Read more »
Black Desert Mobile gets an official rel...
Pearl Abyss has just announced that its highly-anticipated MMO, Black Desert Mobile, will launch globally for iOS and Android on December 11th. [Read more] | Read more »
Another Eden receives new a episode, cha...
Another Eden, WFS' popular RPG, has received another update that brings new story content to the game alongside a few new heroes to discover. [Read more] | Read more »
Overdox guide - Tips and tricks for begi...
Overdox is a clever battle royale that changes things up by adding MOBA mechanics and melee combat to the mix. This new hybrid game can be quite a bit to take in at first, so we’ve put together a list of tips to help you get a leg up on the... | Read more »
Roterra Extreme - Great Escape is a pers...
Roterra Extreme – Great Escape has been described by developers Dig-It Games as a mini-sequel to their acclaimed title Roterra: Flip the Fairytale. It continues that game's tradition of messing with which way is up, tasking you with solving... | Read more »
Hearthstone: Battlegrounds open beta lau...
Remember earlier this year when auto battlers were the latest hotness? We had Auto Chess, DOTA Underlords, Chess Rush, and more all gunning for our attention. They all had their own reasons to play, but, at least from where I'm standing, most... | Read more »
The House of Da Vinci 2 gets a new gamep...
The House of Da Vinci launched all the way back in 2017. Now, developer Blue Brain Games is gearing up to deliver a second dose of The Room-inspired puzzling. Some fresh details have now emerged, alongside the game's first official trailer. [Read... | Read more »
Shoot 'em up action awaits in Battl...
BattleBrew Productions has just introduced another entry into its award winning, barrelpunk inspired, BattleSky Brigade series. Whilst its previous title BattleSky Brigade TapTap provided fans with idle town building gameplay, this time the... | Read more »
Arcade classic R-Type Dimensions EX blas...
If you're a long time fan of shmups and have been looking for something to play lately, Tozai Games may have just released an ideal game for you on iOS. R-Type Dimensions EX brings the first R-Type and its sequel to iOS devices. [Read more] | Read more »

Price Scanner via MacPrices.net

13″ 2.4GHz MacBook Pros available for up to $...
Apple has a full line of Certified Refurbished 2019 13″ 2.4GHz 4-Core Touch Bar MacBook Pros available starting at $1529 and up to $300 off MSRP. Apple’s one-year warranty is included, shipping is... Read more
New at T-Mobile: Switch to T-Mobile, and get...
T-Mobile is offering a free 64GB iPhone 8 for new customers who switch to T-Mobile and open a new line of service. Eligible trade-in required, and discount applied over a 24 month period. The fine... Read more
Xfinity Mobile’s Black Friday Apple savings:...
Take $250 off the purchase of any iPhone at Xfinity Mobile with a new line activation, and transfer of phone number to Xfinity Mobile, through December 8, 2019. This includes Apple’s new iPhone 11... Read more
2019 13″ 1.4GHz MacBook Pros available starti...
Apple has a full line of Certified Refurbished 2019 13″ 1.4GHz 4-Core Touch Bar MacBook Pros available starting at $1099 and up to $230 off MSRP. Apple’s one-year warranty is included, shipping is... Read more
Save up to $350 on a 21″ or 27″ iMac with the...
Apple has Certified Refurbished 2019 21″ & 27″ iMacs available starting at $929 and up to $350 off the cost of new models. Apple’s one-year warranty is standard, shipping is free, and each iMac... Read more
Early Holiday 2019 Sale: B&H again offers...
B&H Photo has 10.2″ iPads on sale again for $30 off Apple’s MSRP, starting at $299, as part of their early Holiday 2019 sale. Overnight shipping is free to many addresses in the US: – 10.2″ 32GB... Read more
Apple iMacs on sale today at B&H Photo fo...
B&H Photo has new 2019 21″ and 27″ 5K iMacs on stock today and on sale for up to $150 off Apple’s MSRP. Overnight shipping is free to many locations in the US. These are the same iMacs sold by... Read more
2018 4 and 6-Core Mac minis on sale today for...
Apple resellers are offering new 2018 4-Core and 6-Core Mac minis for $80-$100 off MSRP for a limited time. B&H Photo has the new 2018 4-Core and 6-Core Mac minis on sale for up to $100 off Apple... Read more
Early Holiday 2019 sale at B&H Photo: 12....
B&H Photo has new 12.9″ iPad Pros on sale for up to $120 off Apple’s MSRP as part of their early Holiday 2019 sale. Overnight shipping is free to many addresses in the US: – 12.9″ 64GB WiFi iPad... Read more
8-Core iMac Pro on sale today for $4499 at B...
B&H Photo has the base 8-Core 3.2GHz 32GB/1TB iMac Pro on sale today for $4499 — $500 off Apple’s MSRP. Shipping is free. Their price is the lowest available for a new iMac Pro from any Apple... Read more

Jobs Board

*Apple* Health Benefit Specialist - Call Cen...
Description ** Apple Health Benefit Specialist - Call Center (MAS 3/MACSC)** **Olympia, WA Multiple Positions** *The ideal candidate for this position will have Read more
Hair Stylist - *Apple* Blossom Mall - JCPen...
Hair Stylist - Apple Blossom Mall Location:Winchester, VA, United States- Apple Blossom Mall 1850 Apple Blossom Dr Job ID:1065040Salon Professionals Job Read more
*Apple* Mobility Pro - Best Buy (United Stat...
**747088BR** **Job Title:** Apple Mobility Pro **Job Category:** Store Associates **Store NUmber or Department:** 000297-Reston-Store **Job Description:** At Best Read more
Nurse Practitioner - Field Based (San Bernard...
Nurse Practitioner - Field Based (San Bernardino, CA, Apple Valley, Hesperia) **Location:** **United States** **Requisition #:** PS30312 **Post Date:** Nov 11, 2019 Read more
Best Buy *Apple* Computing Master - Best Bu...
**747061BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Store NUmber or Department:** 000647-Kildeer-Store **Job Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.