From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8A50810EB37 for ; Thu, 23 Feb 2023 11:26:30 +0000 (UTC) Date: Thu, 23 Feb 2023 12:26:26 +0100 From: Mauro Carvalho Chehab To: Zbigniew =?UTF-8?B?S2VtcGN6ecWEc2tp?= Message-ID: <20230223122626.74b37eab@maurocar-mobl2> In-Reply-To: <20230223105321.49048-1-zbigniew.kempczynski@intel.com> References: <20230223105321.49048-1-zbigniew.kempczynski@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [igt-dev] [PATCH i-g-t 1/3] lib/igt_map: Add 32-bit and 64-bit hash helper functions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: igt-dev@lists.freedesktop.org Errors-To: igt-dev-bounces@lists.freedesktop.org Sender: "igt-dev" List-ID: On Thu, 23 Feb 2023 11:53:19 +0100 Zbigniew Kempczy=C5=84ski wrote: > Creating igt_map requires hashing and comparing function. Common case > is using 32-bit (like fd, etc.) or 64-bit keys (offsets) so adding > such helpers reduces code duplication. >=20 > Signed-off-by: Zbigniew Kempczy=C5=84ski Reviewed-by: Mauro Carvalho Chehab > --- > lib/igt_map.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++ > lib/igt_map.h | 5 +++++ > 2 files changed, 64 insertions(+) >=20 > diff --git a/lib/igt_map.c b/lib/igt_map.c > index da8713a186..ffa1e6beaa 100644 > --- a/lib/igt_map.c > +++ b/lib/igt_map.c > @@ -196,6 +196,7 @@ igt_map_search(struct igt_map *map, const void *key) > * Returns: map entry or %NULL if no entry is found. > * Note that the data pointer may be modified by the user. > */ > + > struct igt_map_entry * > igt_map_search_entry(struct igt_map *map, const void *key) > { > @@ -500,3 +501,61 @@ igt_map_random_entry(struct igt_map *map, > =20 > return NULL; > } > + > +#define GOLDEN_RATIO_PRIME_32 0x9e370001UL > +/** > + * igt_map_hash_32: > + * @key: pointer to 32-bit key > + * > + * Function is hashing function for 32-bit keys. Key is pointer to 32-bit > + * value so it must be dereferenced. > + */ > +uint32_t igt_map_hash_32(const void *key) > +{ > + uint32_t hash =3D *(uint32_t *)key; > + > + hash =3D hash * GOLDEN_RATIO_PRIME_32; > + return hash; > +} > + > +/** > + * igt_map_equal_32: > + * @key1: pointer to first 32-bit key > + * @key2: pointer to second 32-bit key > + * > + * Function compares 32-bit keys. > + */ > +int igt_map_equal_32(const void *key1, const void *key2) > +{ > + return *(uint32_t *)key1 =3D=3D *(uint32_t *)key2; > +} > + > +/* 2^63 + 2^61 - 2^57 + 2^54 - 2^51 - 2^18 + 1 */ > +#define GOLDEN_RATIO_PRIME_64 0x9e37fffffffc0001ULL > +/** > + * igt_map_hash_64: > + * @key: pointer to 64-bit key > + * > + * Function is hashing function for 64-bit keys. Key is pointer to 64-bit > + * value so it must be dereferenced. > + */ > +uint32_t igt_map_hash_64(const void *key) > +{ > + uint64_t hash =3D *(uint64_t *)key; > + > + hash =3D hash * GOLDEN_RATIO_PRIME_64; > + /* High bits are more random, so use them. */ > + return hash >> 32; > +} > + > +/** > + * igt_map_equal_64: > + * @key1: pointer to first 64-bit key > + * @key2: pointer to second 64-bit key > + * > + * Function compares 64-bit keys. > + */ > +int igt_map_equal_64(const void *key1, const void *key2) > +{ > + return *(uint64_t *)key1 =3D=3D *(uint64_t *)key2; > +} > diff --git a/lib/igt_map.h b/lib/igt_map.h > index cadcd6e35f..a0fbd1419f 100644 > --- a/lib/igt_map.h > +++ b/lib/igt_map.h > @@ -171,4 +171,9 @@ igt_map_insert_pre_hashed(struct igt_map *map, > uint32_t hash, > const void *key, void *data); > =20 > +uint32_t igt_map_hash_32(const void *key); > +int igt_map_equal_32(const void *key1, const void *key2); > +uint32_t igt_map_hash_64(const void *key); > +int igt_map_equal_64(const void *key1, const void *key2); > + > #endif