FreeTDS Development Group

[Sam Denton <denton AT wantec.com>]

I would make one request.  Once someone figures out the right way to do the
copy, please document it in the code.

Sam Denton, WAN Technologies, Inc.
(314) 428-0888 / (800) 926-7771 Main Office


-----Original Message-----
From: ZIGLIO Frediano [mailto:Frediano.Ziglio AT vodafoneomnitel.it] 
Sent: Wednesday, June 26, 2002 7:16 AM
To: TDS Development Group
Subject: [freetds] Re: killer query


> 
> Bill,
> 
> TDS 7 is little endian only, so there would be no swapping of 
> bytes.  True 
> this is only valid for direct manipulation of the TDS_UNIQUE 
> structure.  
> The way to deal with this would be to implement the byte swap 
> code for 
> TDS_UNIQUE in tds_swap_datatype().  Given that SYBUNIQUE -> SYBCHAR 
> (currenly) relies on the byte order being little endian, does 
> any of this 
> matter?  If anyone can show me any code that directly manipulates 
> SYBUNIQUE then I think a patch is appropriate, otherwise 
> let's let it be.
> 
> Given that SYBUNIQUE is not part of the original spec no 
> programs should 
> be doing anything with it other than binding as char.  But 
> again, if there 
> is any reason to treat TDS_UNIQUE as anything other than 
> opaque, we should 
> fix it.
> 
> Brian
> 
Watching code more deeply bytes are swapped on tds_swap_datatype() for big
endian machines, so copy beetwen struct should work fine (is same packed
data). But in tds_convert_unique we convert uuid to string using always a
bigendian representation

(from src/tds/convert.c)
        any.c = malloc(37);
 
sprintf(any.c,"%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%
02X%02X",
                buf[0], buf[1], buf[2], buf[3],
                buf[4], buf[5],
                buf[6], buf[7],
                buf[8], buf[9],
                buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]);

Executing this code (from Sql query analizer)

create table #temp ( uuid uniqueidentifier )
insert into #temp values('01020304-0506-0708-0910-111213141516')
select uuid from #temp

Data are returned (on socket stream) in this order
04 03 02 01 06 05 08 07 09 10 11 12 13 14 15 16

freddy77

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