From: Junio C Hamano <gitster@pobox.com>
To: Johannes Schindelin <johannes.schindelin@gmx.de>
Cc: git@vger.kernel.org, Jeff Hostetler <jeffhost@microsoft.com>
Subject: Re: [PATCH 2/5] hashmap: allow memihash computation to be continued
Date: Fri, 17 Feb 2017 21:35:35 -0800 [thread overview]
Message-ID: <xmqq7f4onjrs.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <bd4893f86c4484fc36480848bf2d0905d961e022.1487071883.git.johannes.schindelin@gmx.de> (Johannes Schindelin's message of "Tue, 14 Feb 2017 12:32:07 +0100 (CET)")
Johannes Schindelin <johannes.schindelin@gmx.de> writes:
> diff --git a/hashmap.c b/hashmap.c
> index b10b642229c..061b7d61da6 100644
> --- a/hashmap.c
> +++ b/hashmap.c
> @@ -50,6 +50,20 @@ unsigned int memihash(const void *buf, size_t len)
> return hash;
> }
>
> +/* Incoporate another chunk of data into a memihash computation. */
> +unsigned int memihash_continue(unsigned int hash,
> + const void *buf, size_t len)
> +{
> + const unsigned char *p = buf;
> + while (len--) {
> + unsigned int c = *p++;
> + if (c >= 'a' && c <= 'z')
> + c -= 'a' - 'A';
> + hash = (hash * FNV32_PRIME) ^ c;
> + }
> + return hash;
> +}
This makes me wonder if we want to reduce the duplication (primarily
to avoid risking the loop body to go out of sync) by doing:
unsigned int memihash(const void *buf, size_t len)
{
return memihash_continue(buf, len, FNV32_BASE);
}
If an extra call level really matters, its "inline" equivalent in
the header would probably be good.
next prev parent reply other threads:[~2017-02-18 5:35 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-14 11:31 [PATCH 0/5] A series of performance enhancements in the memihash and name-cache area Johannes Schindelin
2017-02-14 11:31 ` [PATCH 1/5] name-hash: eliminate duplicate memihash call Johannes Schindelin
2017-02-14 11:32 ` [PATCH 2/5] hashmap: allow memihash computation to be continued Johannes Schindelin
2017-02-18 5:35 ` Junio C Hamano [this message]
2017-02-20 12:43 ` Johannes Schindelin
2017-02-20 20:27 ` Junio C Hamano
2017-02-14 11:32 ` [PATCH 3/5] name-hash: precompute hash values during preload-index Johannes Schindelin
2017-02-18 5:47 ` Junio C Hamano
2017-02-19 0:19 ` Jeff Hostetler
2017-02-19 21:45 ` Junio C Hamano
2017-02-14 11:32 ` [PATCH 4/5] name-hash: specify initial size for istate.dir_hash table Johannes Schindelin
2017-02-14 11:32 ` [PATCH 5/5] name-hash: remember previous dir_entry during lazy_init_name_hash Johannes Schindelin
2017-02-14 22:03 ` [PATCH 0/5] A series of performance enhancements in the memihash and name-cache area Jeff King
2017-02-15 14:27 ` Jeff Hostetler
2017-02-15 16:44 ` Jeff King
2017-02-18 5:56 ` Junio C Hamano
2017-02-19 0:02 ` Jeff Hostetler
2017-02-18 5:58 ` Junio C Hamano
2017-02-18 6:29 ` Jeff King
2017-02-18 20:48 ` Junio C Hamano
2017-02-18 23:52 ` Jeff Hostetler
2017-02-19 21:50 ` Junio C Hamano
2017-03-02 21:11 ` Junio C Hamano
2017-03-02 21:18 ` Jeff Hostetler
2017-03-02 21:40 ` Junio C Hamano
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