From owner-cvs-all  Sat Sep 14  3:15: 6 2002
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To: "Greg 'groggy' Lehey" <grog@FreeBSD.org>
Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org
Subject: Re: cvs commit: src/sys/geom geom.h geom_enc.c 
In-Reply-To: Your message of "Sat, 14 Sep 2002 11:00:12 +0930."
             <20020914013012.GU25003@wantadilla.lemis.com> 
Date: Sat, 14 Sep 2002 12:14:52 +0200
Message-ID: <16315.1031998492@critter.freebsd.dk>
From: Poul-Henning Kamp <phk@critter.freebsd.dk>
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In message <20020914013012.GU25003@wantadilla.lemis.com>, "Greg 'groggy' Lehey"
 writes:
>On Friday, 13 September 2002 at  3:33:10 -0700, Poul-Henning Kamp wrote:
>> phk         2002/09/13 03:33:10 PDT
>>
>>   Modified files:
>>     sys/geom             geom.h geom_enc.c
>>   Log:
>>   Add a couple more of the big/little-endian conversion routines and make
>>   them visible from userland, if need be.
>>
>>   I wish that the C language contained this as part of struct definintions,
>>   but failing that, I would settle for an agreed upon set of functions for
>>   packing/unpacking integers in various sizes from byte-streams which may
>>   have unfriendly alignment.
>
>Is there any reason not to use the Linux function names (be32_to_cpu,
>cpu_to_le16, etc.)?

The linux functions, as far as I can tell are:

	uint32_t be32_to_cpu(uint32_t);
	uint32_t cpu_to_be32(uint32_t);

Which results in code like:

		uint32_t u;
		something *ptr;

	#ifdef CPU_WITH_STRICT_ALIGNMENT
		bcopy(ptr, &u, sizeof u);
	#else
		u = *(uint32_t)ptr;
	#endif
		u = be32_to_cpu(u);

I think it is far more logical to have:

	uint32_t be32_dec(void *);
	void be32_enc(uint32_t, void *);

Resulting in code like:

		uint32_t u;
		something *ptr;

		u = be32_dec(ptr);


-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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