Re: OS X Externals

[Frank D. Engel, Jr.]

Unfortunately, there is still a bug somewhere that I can't seem to 
figure out.  Keeps happening... if programming were easy, why would 
anyone do it ;-)

My original Transcript code for dbBLOB is as follows:
function dbBLOB bdat
  put "'" into x
  set the cursor to watch
  repeat for each char c in bdat
    put format("\\\\%03o", charToNum(c)) after x
  end repeat
  return x & "'::bytea"
end dbBLOB
This simply takes each character and yields a zero-padded, three-octet 
number preceded by two backslash '\' characters.  My C equivalent 
reads:

void dbBLOB(char *args[], int nargs, char **retstring, Bool *pass, Bool 
*error)
{
	int retvalue;
	MCstring rdata;
    char *buffer;
	int i, j = 0;
	
	if(nargs != 1)
	{
	    *retstring = 0;
		*pass = False;
		*error = True;
		return;
	}
	
	GetVariableEx(args[0], "", &rdata, &retvalue);
	
	buffer = (char *)malloc(10 + (rdata.length * 5));
	*pass = False;
	*error = False;
	
	buffer[j++] = '\'';
	
	for(i = 0; i < rdata.length; i++)
	{
		buffer[j++] = '\\';
		buffer[j++] = '\\';
		sprintf(&(buffer[j]), "%03o", rdata.sptr[i]);
		j += 3;
	}
	
	buffer[j++] = '\'';
	buffer[j++] = ':';
	buffer[j++] = ':';
	buffer[j++] = 'b';
	buffer[j++] = 'y';
	buffer[j++] = 't';
	buffer[j++] = 'e';
	buffer[j++] = 'a';
	buffer[j] = 0;
	
	*retstring = buffer;
}

The same basic algorithm (except with better memory management to help 
boost the performance somewhat), right?

So why does the output from the Transcript version start with:
\\377\\330\\377\\341\\022\\277
While the output from the C version starts with:
\\377\\377\\377\\377\\022\\377
For the exact same input?
I can only guess that the data is being modified by Rev before it 
reaches the external C function.  Of course, this means that the 
Transcript version works, but the C version does not -- even though the 
C version is *much* faster (of course).  Any takers on how to handle 
this?

Oh, and the C version is called by the Transcript wrapper:
function dbBLOB adat
  put adat into res
  return dbxBLOB("res")
end dbBLOB
Which is designed to make the semantics of the call identical, so that 
I don't have to rework the rest of my code to use the external version 
(and because I like it better this way too).

Thank You!
On Oct 13, 2004, at 1:04 PM, Frank D. Engel, Jr. wrote:
What I just finished doing is creating a small function in Transcript 
which acts as a wrapper for the C function.  The C function returns 
the value to the local variable in the Transcript function, which 
returns the value to the caller in the program.

Thank you everyone, this is working much better now.  Excellent!
On Oct 13, 2004, at 1:00 PM, Dar Scott wrote:
On Oct 13, 2004, at 10:41 AM, Frank D. Engel, Jr. wrote:
That looks doable, but I would have preferred to have the value 
returned by the function (as a return value).  I guess I will use 
(the below) unless someone could tell me how to provide a binary 
return value?
Because of this limitation (and others, such as the 64K limit), I now 
make my externals provide helper functions for a library that has the 
interface I want.  Since externals are associated with a stack, this 
works OK.

I have proposed a couple backward compatible binary interfaces for 
external interface inhancement, but I don't expect anything to happen 
along this line.  (On the other hand, I have been Rip Van Winkle for 
a couple months, so what do I know?)

Dar
****************************************
    Dar Scott Consulting
    http://www.swcp.com/dsc/
    Programming Services
****************************************
_______________________________________________
use-revolution mailing list
[EMAIL PROTECTED]
http://lists.runrev.com/mailman/listinfo/use-revolution

-----------------------------------------------------------
Frank D. Engel, Jr.  <[EMAIL PROTECTED]>
$ ln -s /usr/share/kjvbible /usr/manual
$ true | cat /usr/manual | grep "John 3:16"
John 3:16 For God so loved the world, that he gave his only begotten 
Son, that whosoever believeth in him should not perish, but have 
everlasting life.
$


___________________________________________________________
$0 Web Hosting with up to 120MB web space, 1000 MB Transfer
10 Personalized POP and Web E-mail Accounts, and much more.
Signup at www.doteasy.com
_______________________________________________
use-revolution mailing list
[EMAIL PROTECTED]
http://lists.runrev.com/mailman/listinfo/use-revolution

-----------------------------------------------------------
Frank D. Engel, Jr.  <[EMAIL PROTECTED]>
$ ln -s /usr/share/kjvbible /usr/manual
$ true | cat /usr/manual | grep "John 3:16"
John 3:16 For God so loved the world, that he gave his only begotten 
Son, that whosoever believeth in him should not perish, but have 
everlasting life.
$
_______________________________________________
use-revolution mailing list
[EMAIL PROTECTED]
http://lists.runrev.com/mailman/listinfo/use-revolution