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

EtreCheck 3.1.4 - For troubleshooting yo...
EtreCheck is an app that displays the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to... Read more
Together 3.7 - Store and organize all of...
Together helps you organize your Mac, giving you the ability to store, edit and preview your files in a single clean, uncluttered interface. Features Smart storage. With simple drag-and-drop... Read more
Together 3.7 - Store and organize all of...
Together helps you organize your Mac, giving you the ability to store, edit and preview your files in a single clean, uncluttered interface. Features Smart storage. With simple drag-and-drop... Read more
EtreCheck 3.1.4 - For troubleshooting yo...
EtreCheck is an app that displays the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to... Read more
Postbox 5.0.9 - Powerful and flexible em...
Postbox is a new email application that helps you organize your work life and get stuff done. It has all the elegance and simplicity of Apple Mail, but with more power and flexibility to manage even... Read more
DiskCatalogMaker 6.5.16 - Catalog your d...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast. Finder-like intuitive look and feel. Super-fast search algorithm. Can compress catalog data... Read more
TrailRunner 3.8.827 - Route planning for...
TrailRunner is the perfect companion for runners, bikers, hikers, and all people wandering under the sky. Plan routes on a geographical map. Import GPS or workout recordings and journalize your... Read more
VueScan 9.5.61 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
Postbox 5.0.9 - Powerful and flexible em...
Postbox is a new email application that helps you organize your work life and get stuff done. It has all the elegance and simplicity of Apple Mail, but with more power and flexibility to manage even... Read more
VueScan 9.5.61 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more

Latest Forum Discussions

See All

Great zombie games in the spirit of Dead...
Dead Rising 4 arrives tomorrow, giving enthusiasts a fresh chance to take selfies with zombies and get up to other ridiculous end-of-the-world shenanigans. To really get into the spirit of things, we've gone and gathered the best zombie games that... | Read more »
Amateur Surgeon 4 Guide: Advanced tips a...
Amateur Surgeon 4 is still tackling the competition at the top of the App Store charts, so if you haven't tried it out yet, you should probably do that right away. If you've been at it for a while, though, perhaps you're ready to start expanding... | Read more »
Amateur Surgeon 4 Guide: Become the worl...
It's time to wield your trusty pizza cutter again, as Amateur Surgeon has returned with a whole fresh set of challenges (and some old, familiar ones, too). Starting anew isn't easy, especially when all you have at your disposal is a lighter, the... | Read more »
Le Parker: Sous Chef Extraordinaire (Ga...
Le Parker: Sous Chef Extraordinaire 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »
Telltale Games really is working on a Gu...
Telltale Games' next episodic adventure is indeed Guardians of the Galaxy. A document tied to the voice actors strike suggested that the project was in the work, but now we have direct confirmation following an announcement at the Game Awards that... | Read more »
Amateur Surgeon returns to iOS and Andro...
Amateur Surgeon and its two sequels disappeared from the App Store some time and it was sad days for all. But now, just in time for the holidays, the Adult Swim favorite makes its joyous return in the shape of Amateur Surgeon 4, a remake with... | Read more »
The best board games on mobile
Sometimes you need to ditch all of the high speed, high action games in favor of something a little more traditional. If you don't feel like parting ways from your mobile device, though, there are still plenty of ways to get that old-school fix.... | Read more »
The best Facebook Messenger Instant Game...
Facebook's new Instant Games is now here, meaning you can play games with your friends directly via Facebook. It's a fun new way to connect with friends, of course, but it's also proving to be a solid gaming experience in its own right, with a... | Read more »
You can now play game's on Facebook...
Facebook launched its new Instant Games platform in an exciting new attempt to engage its user base. As a result, you can now play a number of different games directly through Facebook Messenger. All of these games run with HTML5, meaning you play... | Read more »
Apollo Justice Ace Attorney (Games)
Apollo Justice Ace Attorney 1.00.00 Device: iOS Universal Category: Games Price: $.99, Version: 1.00.00 (iTunes) Description: Court Is Back In Session Star as rookie defense attorney, Apollo Justice, as he visits crime scenes,... | Read more »

Price Scanner via MacPrices.net

Monday roundup of Holiday Mac sales: Up to $3...
Take up to $300 off MSRP on the price of a new Apple Mac at B&H Photo today as part of their Holiday sale. Shipping is free, and B&H charges NY sales tax only. Touch Bar MacBook Pros are in... Read more
12-inch WiFi Apple iPad Pros on sale for up t...
B&H Photo has 12″ WiFi Apple iPad Pros on sale for up to $50 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 12″ Space Gray 32GB WiFi iPad Pro: $749 $50 off MSRP... Read more
9-inch Apple WiFi iPad Pros on sale for $20-$...
B&H Photo has 9.7″ Apple WiFi iPad Pros on sale for $20-$50 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 9″ Space Gray 256GB WiFi iPad Pro: $779.95 $20 off MSRP... Read more
Holiday sale: Apple MacBook Airs available fo...
B&H Photo has 13″ MacBook Airs on sale for $100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 1.6GHz/128GB MacBook Air (MMGF2LL/A): $899 $100 off MSRP - 13″ 1.6GHz/... Read more
13-inch Silver Touch Bar MacBook Pro in stock...
Amazon has the new 2016 13″ 2.9GHz/256GB Silver Touch Bar MacBook Pro (MLVP2LL/A) in stock today and on sale for $1749 including free shipping. That’s $50 off MSRP, and it’s the lowest price... Read more
Parallels Toolbox 1.3 for Mac Offers 25 Singl...
Parallels has launched Parallels Toolbox 1.3 for Mac, an upgrade that adds five new utilities to the stand-alone application which was released in August and is available exclusively online at http... Read more
OWC Mercury Elite Pro Dual mini Ultra-Portabl...
OWC has introduced the new OWC Mercury Elite Pro Dual mini, a powerful yet ultra-portable dual-drive RAID solution. The new Mercury Elite Pro Dual mini packs phenomenal performance into a small... Read more
Clearance 13-inch Retina MacBook Pros availab...
B&H Photo has clearance 2015 13″ Retina Apple MacBook Pros available for up to $200 off original MSRP. Shipping is free, and B&H charges NY tax only: - 13″ 2.7GHz/128GB Retina MacBook Pro: $... Read more
Roundup of 2016 13-inch 2.0GHz MacBook Pro sa...
B&H has the non-Touch Bar 13″ MacBook Pros in stock today for $50-$100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.0GHz MacBook Pro Space Gray (MLL42LL/A): $1449 $... Read more
New 13-inch 2.0GHz Space Gray MacBook Pro in...
Adorama has the new 13″ 2.0GHz Space Gray MacBook Pro (non-Touch Bar, MLL42LL/A) in stock for $1499 including a free 3-year AppleCare Protection Plan. Shipping is free, and Adorama charges sales tax... Read more

Jobs Board

Lead *Apple* Solutions Consultant - Apple (...
# Lead Apple Solutions Consultant Job Number: 53586123 Pittsburgh, Pennsylvania, United States Posted: Nov. 28, 2016 Weekly Hours: 40.00 **Job Summary** The Lead ASC Read more
*Apple* Retail - Multiple Positions- Plano,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions- Kansas...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Retail - Multiple Positions- Chicago...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Hardware Design Validation Engineer - *Apple...
The Apple Watch team is looking for a Hardware Design Validation Engineer. This person will be part of the Apple Watch hardware team with responsibilities for Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.