TweetFollow Us on Twitter

XCMD Import Text
Volume Number:4
Issue Number:10
Column Tag:HyperChat®

XCMD Corner

By Donald Koscheka, Apple Computers, Inc.

Importing Text into Hypercard

A new controversy seems to be emerging in the Hypercard community. Some Hypercard pundits are discouraging the use of XCMDs and XFCNs in stack design.. Their most convincing argument is that those of us who jump into writing XCMDs aren’t giving ourselves an opportunity to see if HyperTalk can perform the task, perhaps equally as well as an XCMD.

I frequently consider writing an XCMD solution to a programming problem without first considering whether Hypertalk can do the same job for me. Recently, I needed to import Microsoft WORD files into Hypercard. What a wonderful opportunity to write an XCMD!

When I sat down to write the script to invoke the XCMD, I realized that I could write the entire WORD import routine in HyperTalk. Ed Wischmeyer of Apple Computer Inc. pointed out that although fields in HyperTalk prefer to see straight ASCII text, there is no such restriction on the contents of containers. Hypercard also allows you to open and read any file type you want; you aren’t restricted to reading text files. Of course, you need to figure out how to translate what’s in that container into a format that can be presented in a field.

The hard part of importing text from a Word file is not reading the data into hypercard but rather figuring how Word stores its text. By committing the import code to a simple Hypertalk script, I could concentrate my efforts at decoding Word’s file format.

To simplify my search through the file format, I made the assumption that I could ignore any formatting information such as rulers, font and style changes. I was after was the text portion of the file only. This turns out to be a valid assumption since I wanted to import the file into a Hypercard field as text.

Finding the text was a snap with John Mitchell’s “FEDIT+”. I created a Word file using WORD and then examined it in FEDIT+. I noticed that the text always started at location 256 in the file. Since the size of the file was larger than the size of the text plus this 256 byte header, I needed to determine where the end of text occurred (assuming that the formatting and ruler information follows the text in the file). Since I knew how long the text was, I again used FEDIT+ to search the 256 header portion of the file. This time I was looking for any portion of the header that contained a count of the number of bytes in the text. Since I knew that my file contained exactly 100 characters (bytes), all I had to do was find this number somewhere in the header portion of the file. I found something close to what I was looking for at offset 16 in the file. This location corresponded to the number of characters in the text portion of the file plus 256 which was the length of the header.

The creators of Microsoft Word may be reading this and wondering why I’m assuming that the text size is a 16-bit entity rather than a 32 bit number. I’m not. Since Hypercard text fields are currently limited to 32K bytes, and since I knew none of my word files were longer than this, I’m only interested in the low-order word of the text length.

Reading the text portion of a Microsoft Word file into a hypercard container requires the following steps: (1) Position the mark at byte 16 of the file. Read the byte at this position and multiply it by 256 making it the high-order half of the file length. Read the next byte and add it to the hight-order half of the length. Move 238 more bytes into the file (16+2+238 = 256). This is the start of the text portion of the file. Read the number of bytes calculated minus 256. The IT container gets the imported text.

The Hypertalk script in listing 1 performs the above steps for importing up to 16K bytes of text from a Word file. I use Steisplay WORD files only in the GetFile dialog and to get the full pathname of the file from the user. This script reads in the text without any looping so an XCMD may not speed things up enough to be warranted.

{1}
on mouseup
  put filename(“WDBN”)into filename
  if filename is not empty then
     open file filename -- filename is the full pathname of a WORD file
     read from file filename for 16 -- move file mark to the text length 
word
     read from file filename for 1  -- read the upper half of the length
     put chartonum( it ) * 256 into filesize -- shift up by 8 bits
     read from file filename for 1  -- get the lower half of the length
     add chartonum( it ) mod 256 to filesize
     read from file filename for 238-- move to start of text in the file
     read from file filename for filesize-256 -- read in the text
     close file filename -- IT now contains the imported data.    
  end if
end mouseup

Listing 1. Script to Import Text from a Microsoft Word File

Not all file formats can be imported quite so simply. Macwrite uses a packed text format, storing one or two characters per byte using a simple compression scheme.

Because the text is compressed, we can’t just read the file into a container and return the result to Hypercard. We must first decompress the file a byte at a time. Such a process suggests looping and loops, as we know, are not particularly fast in HyperTalk. Although the decompression can be performed in a hypertalk script, we can write an xcmd that performs the decompression faster.

The key to reading in a MacWrite file is understanding that Macwrite stores its data by paragraph. Whereas Word files are clearly divided between the text and formatting information, Macwrite stores formatting information for each paragraph at the end of the text for that paragraph. Hypercard doesn’t do formatted text; we want to ignore the formatting information at the end of each paragraph. Our algorithm then becomes a loop that reads in a paragraph at a time, decompresses the text for that paragraph ignoring the formatting information. This process is repeated for each paragraph in the file.

One small “gotcha” to this approach stems from the fact that Rulers and pictures are also considered paragraphs. When we encounter either of these objects, we just move on to the next paragraph.

Listing 2 depicts the code for this XFCN. I chose “C” because pointer arithmetic is easier to perform in “C” and because last month’s example was written in Pascal. I made every attempt to keep the “C” isomorphic to a Pascal program so that you can easily convert the code to Pascal.

Finding the paragraph information in the file requires a little arithmetic. Bytes 2-3 in the file tell us how many paragraphs the main document contains (MacWrite makes a distinction between the main document, the header document and the footer document. For our purposes, we only want to read in the main body of text) If bytes 2-3 contain a 5 then there are 5 paragraphs in the main document.

For each paragraph, MacWrite stores an information array. We start reading the information arrays at the file position pointed to in file offset $108. An information array is an array of 16-byte elements that tell us something about each paragraph. The first two bytes in the information array tell us whether the paragraph contains text, a ruler or a picture. If this value is positive the paragraph contains text, if this value is 0 or negative the paragraph is a ruler or a picture respectively and we can ignore it.

Offset 8 in the information array contains a status byte that provides some information about the text. If bit 3 is set, the text in this paragraph is compressed. Bytes 9-11 tell us the absolute file offset for the start of the data in the paragraph and bytes 12-13 contain the length of the data (paragraph addressing is 24 bits and each paragraph contains up to 64K of characters or data). The trick is to read in the number of characters indicated in the information array, determine if the paragraph contains text and, if so, decompress the text if it’s compressed.

Once we read in the paragraph, we get some more information. The first two bytes of the paragraph tell us how many characters of text will appear in the decompressed paragraph. Following the text on an even word boundary is the formatting information for the paragraph which we ignore in this example.

MacWrite’s text compression is based on a letter frequency scheme stored as STR resource #700 in MacWrite’s resource fork. For English, this string contains “ etnroaisdlhcfp”. Macwrite maps these characters onto the array [$0..$F]. The space character ($20) has a value of 0, letter “e” has a value of 1, “t” a value of 2 and so on. Since any number less than $F can fit into a nibble, the word “eels” can be represented as “$11A8” rather than the byte-wide representation of $65656C73. In this example, we realize a 50% space saving (the best case for this algorithm).

This compression scheme only works for lower-case letters since 4 bits is not enough information to code for word frequency and case for the 14 most popular letters. This scheme also doesn’t compress non-alphabetic characters such as numerals and punctuation marks. In these cases, the 16th array element, $F, is used as a flag to tell indicate that the next 2 nibbles represent one character. “Then” would be coded as $F55906. Note that the letter “T” crosses byte boundaries, the top nibble is in byte 0 and the lower nibble is in byte 1. This is of no consequence to the algorithm.

Armed with this information, you should have little trouble understanding the XFCN. In fact, I hope you find it useful and informative! (Next month: printing from XCMDs).

{2}
/*************************\
*file:  MWRead.c *
*  *
* an XFCN that imports text *
* directly from a MacWrite file  *
* whose full pathname is passed  *
* as an input parameter.  *
**
* -------------------------------- *
* To Build this file:*
**
*C -q2 -g MWRead.c *
**
*link -sn Main=MWRead    *
*-sn STDIO=MWRead *
*-sn INTENV=MWRead  *
*-rt XFCN=301   *
*-m MWREAD MWRead.c.o    *
*“{CLibraries}”CInterface.o  *
*-o “your stack name”*
**
* -------------------------------- *
* By: Donald Koscheka*
* Date: 2-July-1988*
* ©1988, Donald Koscheka  *
*All Rights Reserved *
**
* -------------------------------- *
\*************************/

#include<Types.h>
#include<OSUtils.h>
#include<Memory.h>
#include<Files.h>
#include<Resources.h>
#include  “HyperXCmd.h”

#define INFOPOS  0x00000108
#define PPOS0x00000002
#define COMP0x0008


/* -------------------------- */
/* Define the structure of an */
/* information array element*/
/* */
/* pHite is positive if this*/
/* info array points to text, */
/* ignored otherwise.*/
/* */
/* fPos is the absolute file*/
/* position of the start of */
/* the paragraph in the file*/
/* */
/* fLen is the total length of*/
/* the file including formats */
/* -------------------------- */

typedef struct infoArr {
 short  pHite;/* parag hite */
 short  pixels;/* ignore this */ 
 long pHand;/* ignore this*/
 char status;/* chk comprsn */
 char hiMark;/* msw of mark */
 short  loMark;/* lsw of mark */
 short  fLen;  /* parag. len*/
 short  fmat;  /* ignore this */ 
}infoArr;

/* ------------------------ */

short   ReadFile();
Handle  DeCompress();


pascal void MWRead( paramPtr )
 XCmdBlockPtr  paramPtr;
/*************************
* In:ParamPtr:
*pointer to XCMD param
*block. params[0] is the
*name of the macwrite file
*  to open.
*
* Out:ParamPtr->returnValue
*empty if data could not
*be read, text portion 
*of a   Macwrite document.
*************************/
{
short 
 ref,   /* file reference */
 err,   /* io error  */
 vRef,  /* vol reference  */
 pcnt,  /* #  paragraphs  */
 tSiz,  /* text length  */
 loop;  /* loop counter */
long  
 fSiz,  /* data size */
 iSiz,  /* out data size  */
 iMark,/* iarr file pos */
 fPos;  /* para. offset */
Handle
 ImportText,
 decomp,/* decompressed*/
 temp;
infoArr
 info;
char 
 *fName,
 vName[32];

ImportText = nil;

if( paramPtr->params[0] != nil ){
HLock( paramPtr->params[0] );

GetVol( vName, &vRef );
fName = *(paramPtr->params[0]);
err = FSOpen( fName, vRef, &ref );
HUnlock( paramPtr->params[0] );

if( err == noErr ){
 ImportText = NewHandle( 0 );
 
 /* get paragraph count   */
 fSiz = sizeof( short );
 err=ReadFile(ref,fSiz,&pcnt,(long)PPOS);
 
 /* get infoArray position*/
 fSiz = sizeof( long );
 err=ReadFile(ref,fSiz,&iMark,(long)INFOPOS);
 
 /* read in the paragraphs*/
 for( loop = 0; loop < pcnt; loop++){
 fSiz = sizeof( infoArr );
 err=ReadFile(ref,fSiz,&info,iMark);
 
 if( info.pHite > 0 ){
 /* paragraph is text*/
 
 /* calc text position  */
 fPos=(info.hiMark<<0x10)+info.loMark;
 
 /* get the char count  */
 fSiz = sizeof( short );
 err = ReadFile(ref,fSiz,&tSiz,fPos);
 
 /* read in the text */
 temp = NewHandle((long)tSiz);
 HLock( temp );
 fPos += 2; 
 fSiz = (long)tSiz;
 err = ReadFile(ref,fSiz,*temp,fPos);
 
 if( info.status & COMP ){
 /* paragraph is compressed */
 HLock( temp );
 
 decomp = DeCompress( *temp, tSiz );
 
 HUnlock( temp );
 DisposHandle( temp );
 
 temp = decomp;
 tSiz = (short)GetHandleSize( decomp ); 
 }/* if( info.status & COMP ) */
 
 iSiz = GetHandleSize( ImportText );
 fSiz = (long)tSiz;
 SetHandleSize( ImportText, iSiz+fSiz );
 BlockMove(*temp,(*ImportText)+iSiz,fSiz);
 
 HUnlock( temp );
 DisposHandle( temp );
 }/* if( info.pHite > 0 ) */
 
 iMark = iMark + sizeof( infoArr );
 
 }/* FOR paragraph count  */

 iSiz = GetHandleSize( ImportText );
 SetHandleSize( ImportText, iSiz+1 );
 *((*ImportText)+iSiz) = ‘\0’;
 
 FSClose( ref );
 FlushVol( nil, vRef );
}/* if file opened ok     */

paramPtr->returnValue = ImportText;
}

}

short   ReadFile(ioRef,siz,buf,from)
short   ioRef;
long    siz;
char    *buf;
long    from;
/*************************
* read cnt bytes from the file specified by parms and put 
* the data into the buffer pointed to by buf 
*
* ioRef = file reference number
* siz = number of bytes to read
* buf = where to read in to
* from  = where in file to read from
*
* from is the file mark relative to the start of the file from
* which the read is to start.
*************************/
{
 short  err;
 
 err = SetFPos( ioRef, fsFromStart, from );
 if( err == noErr )
 err = FSRead( ioRef, &siz, buf ); 
 return( err);
}

Handle DeCompress( inp, expcnt )
 char *inp;
 short  expcnt;
/***********************
* Decompress the input handle’s data (inH) and put the result
* in the output Handle (outH).  outH is sized properly and 
* we use the following scheme:
*
*0 1 2 3 4 5 6 7 8 9 A B C D E F
*_ e t n r o a i s d l h c f p !
*
* where _ = SPACE
*! = not compressed
* 
* Consult MacWrite resource str #700 for the decompression
* string in your file (different for other languages).
* cycle through until the decompressed string count 
* matches the expected count
***********************/
{
 short  chcnt;
 register char *op;
 register char hiNib;
 register char loNib;
 char   dc[16];
 Handle outH;
 
 outH = NewHandle( (long)expcnt );

 dc[0]  = 0x020;
 dc[1]  = ‘e’;
 dc[2]  = ‘t’;
 dc[3]  = ‘n’;
 dc[4]  = ‘r’;
 dc[5]  = ‘o’;
 dc[6]  = ‘a’;
 dc[7]  = ‘i’;
 dc[8]  = ‘s’;
 dc[9]  = ‘d’;
 dc[10] = ‘l’;
 dc[11] = ‘h’;
 dc[12] = ‘c’;
 dc[13] = ‘f’;
 dc[14] = ‘p’;
 
 HLock( outH );
 op = *outH;
 chcnt = 0;
 
 while( chcnt < expcnt ){
 hiNib = loNib = *inp++;
 hiNib = hiNib >> 0x04;
 hiNib &=  0x000F;
 loNib &=  0x000F;
 
 if( hiNib < 0x0F ){
 *op++ = dc[hiNib];
 chcnt++;
 if( loNib < 0x0F ){
 *op++ = dc[loNib];
 chcnt++;
 }
 else{ /* next BYTE is a char */
 *op++ = *inp++;
 chcnt++;
 }
 }
 else{
 /* next 2 nibbles represent*/
 /* a complete char which */
 /* is on odd-nibble bounds */
 
 *op  = loNib << 0x04;
 hiNib  = *inp++;
 loNib = hiNib & 0x000F;
 hiNib = hiNib >> 0x04;
 hiNib &= 0x0F;
 *op  = *op | hiNib;
 op++;
 chcnt++;
 
 if( loNib < 0x0F )
 *op++ = dc[loNib];
 else
 *op++ = *inp++;
 chcnt++;
 }
 }
 HUnlock( outH );
 return( outH );
}

#include <XCmdGlue.inc.c>

Listing 2. XFCN to import trxt from a MacWrite Document

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Capture One 15.3.1 - RAW workflow softwa...
Capture One is a professional RAW converter offering you ultimate image quality with accurate colors and incredible detail from more than 400 high-end cameras - straight out of the box. It offers... Read more
Connect Fonts 23.0.3 - Font management s...
Connect Fonts is the creative professional's font manager. Every professional font manager should deliver the basics: spectacular previews, powerful search tools, and efficient font organization. You... Read more
CleanMyMac X 4.11.0 - Delete files that...
CleanMyMac X makes space for the things you love. Sporting a range of ingenious new features, CleanMyMac lets you safely and intelligently scan and clean your entire system, delete large, unused... Read more
Firefox 102.0 - Fast, safe Web browser.
Firefox offers a fast, safe Web browsing experience. Browse quickly, securely, and effortlessly. With its industry-leading features, Firefox is the choice of Web development professionals and casual... Read more
Hopper Disassembler 5.6.1 - Binary disas...
Hopper Disassembler is a binary disassembler, decompiler, and debugger for 32- and 64-bit executables. It will let you disassemble any binary you want, and provide you all the information about its... Read more
Skim 1.6.11 - PDF reader and note-taker...
Skim is a PDF reader and note-taker for OS X. It is designed to help you read and annotate scientific papers in PDF, but is also great for viewing any PDF file. Skim includes many features and has a... Read more
Alfred 4.6.7 - Quick launcher for apps a...
Alfred is an award-winning productivity application for OS X. Alfred saves you time when you search for files online or on your Mac. Be more productive with hotkeys, keywords, and file actions at... Read more
Transmit 5.8.7 - Excellent FTP/SFTP clie...
Transmit is an excellent FTP (file transfer protocol), SFTP, S3 (Amazon.com file hosting) and iDisk/WebDAV client that allows you to upload, download, and delete files over the internet. With the... Read more
Adobe Lightroom Classic 11.4.1 - Import,...
You can download Lightroom for Mac as a part of Creative Cloud for only $9.99/month with Photoshop, included as part of the photography package. The latest version of Lightroom gives you all of the... Read more
MarsEdit 4.5.9 - Quick and convenient bl...
MarsEdit is a blog editor for OS X that makes editing your blog like writing email, with spell-checking, drafts, multiple windows, and even AppleScript support. It works with with most blog services... Read more

Latest Forum Discussions

See All

Apple Arcade Weekly Round-Up: Major Upda...
Apple recently revealed July’s upcoming Apple Arcade releases in a new App Store Story, and this week’s new release is My Bowling 3D+ featuring offline and online multiplayer support, and more. It arrives from the developers of Pro Darts 2022+ and... | Read more »
Downhill Mountain Biking Game ‘Descender...
Just over three years ago in May of 2019 developer RageSquid and publisher No More Robots released a quirky downhill mountain biking game called Descenders on PC and Xbox One. Bemoaning a lack of “extreme sports" titles in recent years led RageSquid... | Read more »
SwitchArcade Round-Up: ‘Monster Hunter R...
Hello gentle readers, and welcome to the SwitchArcade Round-Up for June 30th, 2022. Thursday is once more upon us, and that means a bunch of new releases to look at. We start things off with DLC for some very big games, Monster Hunter Rise and... | Read more »
‘HOOK 2’ Review – A Sharp Left Hook From...
The original HOOK ($1.99) had a very simple idea behind it. You were presented with a tangled mess of hooks and loops, and you needed to remove each one without snagging any others. Extremely simple at first, but as the puzzles rolled along,... | Read more »
‘Dicey Dungeons’ Mobile Version Launchin...
After a very long wait, Terry Cavanagh’s dungeon crawling roguelite deckbuiler hybrid experience Dicey Dungeons is coming to mobile platforms next week alongside a huge free DLC pack on all platforms. This DLC will be included in the mobile... | Read more »
Distract Yourself With These Great Mobil...
Every day, we pick out a curated list of the best mobile discounts on the App Store and post them here. This list won't be comprehensive, but it every game on it is recommended. Feel free to check out the coverage we did on them in the links below... | Read more »
‘Danganronpa S: Ultimate Summer Camp’ is...
If you’ve been following Danganronp over the last few years, Spike Chunsoft celebrated its anniversary by bringing the series to mobile in the form of anniversary editions. After the first two released, there was a long delay for V3, but it finally... | Read more »
Out Now: ‘HOOK 2’, ‘Incoherence’, ‘Juras...
Each and every day new mobile games are hitting the App Store, and so each week we put together a big old list of all the best new releases of the past seven days. Back in the day the App Store would showcase the same games for a week, and then... | Read more »
Upcoming Mobile MMO RPG Shooter ‘Avatar:...
This past January a contingent of developers made up of Archosaur Games, Tencent, Lightstorm Entertainment, and Disney announced a new mobile game set in James Cameron’s Avatar universe titled Avatar: Reckoning. | Read more »
Culinary Platformer ‘Chefy-Chef’ Coming...
If your name is Chefy, it’s pretty much a given that you should be a chef. Such is the case with Chefy-Chef, a game from Bug Studio about a chef named Chefy who must travel to all sorts of exotic locations using a magical refrigerator in an effort... | Read more »

Price Scanner via MacPrices.net

July 4th sale at Verizon: Apple AirPods Pro f...
Verizon has Apple AirPods Pro on sale for $179.99 on their online store as part of their Fourth of July sale. Their price is $70 (28%) off Apple’s MSRP, and it’s among the lowest prices currently... Read more
Apple is now selling Certified Refurbished Ma...
Apple has added a full line of standard-configuration Mac Studios available in their Certified Refurbished section starting at only $1799 and ranging up to $400 off MSRP. Each Mac Studio comes with... Read more
Open-box 14″ M1 Pro MacBook Pros in stock tod...
QuickShip Electronics has open-box return Space Gray 14″ M1 Pro MacBook Pros in stock and on sale for $300-$450 off MSRP on their eBay store today. According to QuickShip, “The item in this listing... Read more
Can Being An iPhone User Really Determine Whe...
FEATURE: – If you’re traveling on the road today for the July 4th holiday, you might want to keep your Apple smartphone locked up inside the car’s glove compartment for your (and, everyone else’s)... Read more
2nd generation 4K Apple TVs with Siri remote...
Apple has restocked a full line of Certified Refurbished 2nd generation 32GB and 64GB 4K Apple TVs with Siri remotes for $30 off the cost of new models. Apple’s standard one-year warranty is included... Read more
Back in stock: Apple Watch Series 7 models fo...
Apple has restocked Certified Refurbished Apple Watch Series 7 WiFi-only models in their online store for $60-$70 off MSRP, starting at $339. Each Watch includes Apple’s standard one-year warranty, a... Read more
July 4th Sale at Expercom: $200 off any 16″ M...
Apple reseller Expercom has 16″ M1 Pro and M1 Max MacBook Pros available for $200 off MSRP as part of their July 4th sale. In addition to their MacBook Pro sale prices, take $50 off AppleCare+ when... Read more
10.2″ Apple iPads (WiFi models) are on sale f...
Amazon has Apple’s 9th generation 10.2″ WiFi iPads on sale for up to $20-$50 off MSRP for a limited time. Their prices are the lowest price currently available for one of these iPads. All models are... Read more
10-Core M1 Pro 14″ MacBook Pros on sale for $...
B&H Photo is offering $200 discounts on Apple’s new 14″ M1 Pro MacBook Pros with 10-Core CPUs (16GB RAM/1TB SSDs). Free 1-2 day shipping is available to most US addresses, and both models are in... Read more
B&H has 16-inch M1 Pro MacBook Pros in st...
New Space Gray 16″ MacBook Pros with Apple’s M1 Pro CPUs are in stock and on sale today at B&H Photo for $200 off Apple’s MSRP. Sale prices are for M1 Pro models with 512GB or 1TB of SSD storage... Read more

Jobs Board

VP, Software Engineering - *Apple* and Andr...
…Client Application Software Engineering team is seeking a VP, Software Engineering for Apple and Android. You will lead the client engineering team building Disney+, Read more
I/S Senior Engineer - *Apple* Systems Engin...
**19647BR** **Position Title:** I/S Senior Engineer - Apple Systems Engineering - Remote **Department:** Information Systems **Location:** Lakeland, FL between Read more
*Apple* IT Support Analyst - 2nd Shift - Zon...
Apple IT Support Analyst - 2nd Shift Professional Services Albany, New York Malta, New York Clifton Park, New York Menands, New York Syracuse, New York Watertown, Read more
Infotainment Certification Test Engineer (XC)...
…integration - CarPlay, android auto, MirrorLink, Baidu Carlife, MFi/iPod certification testing; Apple PPID preparation, Google HUCD and GTM preparation + 3 years of Read more
Workplace Services *Apple* Device Managemen...
…3350 Riverwood Parkway Suite 900, Atlanta, GA, 30339 USA **Workplace Services Apple Device Management** **Role Overview** Carrier is seeking an experienced and Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.