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-rw-r--r--debian/patches/0003-libihash-use-linear-probing-and-fast-modulo-operatio.patch236
1 files changed, 0 insertions, 236 deletions
diff --git a/debian/patches/0003-libihash-use-linear-probing-and-fast-modulo-operatio.patch b/debian/patches/0003-libihash-use-linear-probing-and-fast-modulo-operatio.patch
deleted file mode 100644
index e1cce7e5..00000000
--- a/debian/patches/0003-libihash-use-linear-probing-and-fast-modulo-operatio.patch
+++ /dev/null
@@ -1,236 +0,0 @@
-From aa4d444a81c32e2f1036041ad7474fb13b8bf693 Mon Sep 17 00:00:00 2001
-From: Justus Winter <4winter@informatik.uni-hamburg.de>
-Date: Thu, 8 May 2014 18:33:57 +0200
-Subject: [PATCH 03/15] libihash: use linear probing and fast modulo operation
-
-libihash uses open addressing. Previously, quadratic probing in both
-directions was used to resolve collisions. Quadratic probing might
-result in a less efficient use of caches.
-
-Also, prime numbers of the form 4 * i + 3 were used as array sizes.
-This was used in combination with the integer modulo operation for
-hashing. It has been known for some time that libihash suffers from
-collisions, so a integer hash function is now applied to the keys to
-derive the index.
-
-Use linear probing instead. Also, use powers of two for the array
-sizes, so a bit mask can be used for the modulo operation.
-
-* libihash/ihash.c (ihash_sizes, ihash_nsizes): Remove.
-(find_index): Use linear probing and fast modulo operation.
-(add_one): Likewise.
-* libihash/ihash.h (HURD_IHASH_MIN_SIZE): New macro.
----
- libihash/ihash.c | 125 +++++++------------------------------------------------
- libihash/ihash.h | 4 ++
- 2 files changed, 19 insertions(+), 110 deletions(-)
-
-diff --git a/libihash/ihash.c b/libihash/ihash.c
-index 71ddc26..d628d75 100644
---- a/libihash/ihash.c
-+++ b/libihash/ihash.c
-@@ -31,55 +31,6 @@
- #include <assert.h>
-
- #include "ihash.h"
--
--
--/* The prime numbers of the form 4 * i + 3 for some i, all greater
-- than twice the previous one and smaller than 2^40 (for now). */
--static const uint64_t ihash_sizes[] =
--{
-- 3,
-- 7,
-- 19,
-- 43,
-- 103,
-- 211,
-- 431,
-- 863,
-- 1747,
-- 3499,
-- 7019,
-- 14051,
-- 28111,
-- 56239,
-- 112507,
-- 225023,
-- 450067,
-- 900139,
-- 1800311,
-- 3600659,
-- 7201351,
-- 14402743,
-- 28805519,
-- 57611039,
-- 115222091,
-- 230444239,
-- 460888499,
-- 921777067,
-- 1843554151,
-- UINT64_C (3687108307),
-- UINT64_C (7374216631),
-- UINT64_C (14748433279),
-- UINT64_C (29496866579),
-- UINT64_C (58993733159),
-- UINT64_C (117987466379),
-- UINT64_C (235974932759),
-- UINT64_C (471949865531),
-- UINT64_C (943899731087)
--};
--
--static const unsigned int ihash_nsizes = (sizeof ihash_sizes
-- / sizeof ihash_sizes[0]);
--
-
- /* This is the integer finalizer from MurmurHash3. */
- static inline uint32_t
-@@ -120,40 +71,24 @@ static inline int
- find_index (hurd_ihash_t ht, hurd_ihash_key_t key)
- {
- unsigned int idx;
-- unsigned int i;
- unsigned int up_idx;
-- unsigned int down_idx;
-+ unsigned int mask = ht->size - 1;
-
-- idx = murmur3_mix32 (key, 32) % ht->size;
-+ idx = murmur3_mix32 (key, __builtin_ctz (ht->size));
-
- if (ht->items[idx].value == _HURD_IHASH_EMPTY || ht->items[idx].key == key)
- return idx;
-
-- /* Instead of calculating idx + 1, idx + 4, idx + 9, ..., idx + i^2,
-- we add 1, 3, 5, 7, etc to the previous index. We do this in both
-- directions separately. */
-- i = 1;
- up_idx = idx;
-- down_idx = idx;
-
- do
- {
-- up_idx = (up_idx + i) % ht->size;
-+ up_idx = (up_idx + 1) & mask;
- if (ht->items[up_idx].value == _HURD_IHASH_EMPTY
- || ht->items[up_idx].key == key)
- return up_idx;
--
-- if (down_idx < i)
-- down_idx += ht->size;
-- down_idx = (down_idx - i) % ht->size;
-- if (ht->items[down_idx].value == _HURD_IHASH_EMPTY
-- || ht->items[down_idx].key == key)
-- return down_idx;
--
-- /* After (ht->size - 1) / 2 iterations, this will be 0. */
-- i = (i + 2) % ht->size;
- }
-- while (i);
-+ while (up_idx != idx);
-
- /* If we end up here, the item could not be found. Return any
- invalid index. */
-@@ -277,52 +212,25 @@ add_one (hurd_ihash_t ht, hurd_ihash_key_t key, hurd_ihash_value_t value)
- unsigned int idx;
- unsigned int first_free;
-
-- idx = murmur3_mix32 (key, 32) % ht->size;
-+ idx = murmur3_mix32 (key, __builtin_ctz (ht->size));
- first_free = idx;
-
- if (ht->items[idx].value != _HURD_IHASH_EMPTY && ht->items[idx].key != key)
- {
-- /* Instead of calculating idx + 1, idx + 4, idx + 9, ..., idx +
-- i^2, we add 1, 3, 5, 7, ... 2 * i - 1 to the previous index.
-- We do this in both directions separately. */
-- unsigned int i = 1;
-+ unsigned int mask = ht->size - 1;
- unsigned int up_idx = idx;
-- unsigned int down_idx = idx;
--
-+
- do
- {
-- up_idx = (up_idx + i) % ht->size;
-+ up_idx = (up_idx + 1) & mask;
- if (ht->items[up_idx].value == _HURD_IHASH_EMPTY
- || ht->items[up_idx].key == key)
- {
- idx = up_idx;
- break;
- }
-- if (first_free == idx
-- && ht->items[up_idx].value == _HURD_IHASH_DELETED)
-- first_free = up_idx;
--
-- if (down_idx < i)
-- down_idx += ht->size;
-- down_idx = (down_idx - i) % ht->size;
-- if (down_idx < 0)
-- down_idx += ht->size;
-- else
-- down_idx %= ht->size;
-- if (ht->items[down_idx].value == _HURD_IHASH_EMPTY
-- || ht->items[down_idx].key == key)
-- {
-- idx = down_idx;
-- break;
-- }
-- if (first_free == idx
-- && ht->items[down_idx].value == _HURD_IHASH_DELETED)
-- first_free = down_idx;
--
-- /* After (ht->size - 1) / 2 iterations, this will be 0. */
-- i = (i + 2) % ht->size;
- }
-- while (i);
-+ while (up_idx != idx);
- }
-
- /* Remove the old entry for this key if necessary. */
-@@ -365,21 +273,18 @@ hurd_ihash_add (hurd_ihash_t ht, hurd_ihash_key_t key, hurd_ihash_value_t item)
- if (ht->size)
- {
- /* Only fill the hash table up to its maximum load factor. */
-- if (ht->nr_items * 100 / ht->size <= ht->max_load)
-+ if ((ht->nr_items * 100) >> __builtin_ctz (ht->size) <= ht->max_load)
- if (add_one (ht, key, item))
- return 0;
- }
-
- /* The hash table is too small, and we have to increase it. */
-- for (i = 0; i < ihash_nsizes; i++)
-- if (ihash_sizes[i] > old_ht.size)
-- break;
-- if (i == ihash_nsizes
-- || ihash_sizes[i] > SIZE_MAX / sizeof (struct _hurd_ihash_item))
-- return ENOMEM; /* Surely will be true momentarily. */
--
- ht->nr_items = 0;
-- ht->size = ihash_sizes[i];
-+ if (ht->size == 0)
-+ ht->size = HURD_IHASH_MIN_SIZE;
-+ else
-+ ht->size <<= 1;
-+
- /* calloc() will initialize all values to _HURD_IHASH_EMPTY implicitely. */
- ht->items = calloc (ht->size, sizeof (struct _hurd_ihash_item));
-
-diff --git a/libihash/ihash.h b/libihash/ihash.h
-index a24f384..8829e51 100644
---- a/libihash/ihash.h
-+++ b/libihash/ihash.h
-@@ -93,6 +93,10 @@ typedef struct hurd_ihash *hurd_ihash_t;
-
- /* Construction and destruction of hash tables. */
-
-+/* The size of the initial allocation in number of items. This must
-+ be a power of two. */
-+#define HURD_IHASH_MIN_SIZE 32
-+
- /* The default value for the maximum load factor in percent. */
- #define HURD_IHASH_MAX_LOAD_DEFAULT 75
-
---
-2.0.0.rc0
-
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