util: Move the open-addressing linear-probing hash_table to src/util.

This hash table is used in core Mesa, the GLSL compiler, and the i965
driver, which makes it a good candidate for the new src/util module.

It's much faster than program/hash_table.[ch] (see commit 6991c2922f5
for data), and José's u_hash_table.c has a comment saying Gallium should
probably consider switching to a linear probing hash table at some point.
So this seems like the best candidate for a shared data structure.

Signed-off-by: Kenneth Graunke <[email protected]>

v2 (Jason Ekstrand): Pick up another hash_table use and patch up scons

Signed-off-by: Jason Ekstrand <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>

1 files changed, 440 insertions, 0 deletions

diff --git a/src/util/hash_table.c b/src/util/hash_table.c
new file mode 100644
index 00000000000..f98a1a647ea
--- /dev/null
+++ b/src/util/hash_table.c
@@ -0,0 +1,440 @@
+/*
+ * Copyright © 2009,2012 Intel Corporation
+ * Copyright © 1988-2004 Keith Packard and Bart Massey.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the names of the authors
+ * or their institutions shall not be used in advertising or
+ * otherwise to promote the sale, use or other dealings in this
+ * Software without prior written authorization from the
+ * authors.
+ *
+ * Authors:
+ *    Eric Anholt <[email protected]>
+ *    Keith Packard <[email protected]>
+ */
+
+/**
+ * Implements an open-addressing, linear-reprobing hash table.
+ *
+ * For more information, see:
+ *
+ * http://cgit.freedesktop.org/~anholt/hash_table/tree/README
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "hash_table.h"
+#include "main/macros.h"
+#include "ralloc.h"
+
+static const uint32_t deleted_key_value;
+
+/**
+ * From Knuth -- a good choice for hash/rehash values is p, p-2 where
+ * p and p-2 are both prime.  These tables are sized to have an extra 10%
+ * free to avoid exponential performance degradation as the hash table fills
+ */
+static const struct {
+   uint32_t max_entries, size, rehash;
+} hash_sizes[] = {
+   { 2,			5,		3	  },
+   { 4,			7,		5	  },
+   { 8,			13,		11	  },
+   { 16,		19,		17	  },
+   { 32,		43,		41        },
+   { 64,		73,		71        },
+   { 128,		151,		149       },
+   { 256,		283,		281       },
+   { 512,		571,		569       },
+   { 1024,		1153,		1151      },
+   { 2048,		2269,		2267      },
+   { 4096,		4519,		4517      },
+   { 8192,		9013,		9011      },
+   { 16384,		18043,		18041     },
+   { 32768,		36109,		36107     },
+   { 65536,		72091,		72089     },
+   { 131072,		144409,		144407    },
+   { 262144,		288361,		288359    },
+   { 524288,		576883,		576881    },
+   { 1048576,		1153459,	1153457   },
+   { 2097152,		2307163,	2307161   },
+   { 4194304,		4613893,	4613891   },
+   { 8388608,		9227641,	9227639   },
+   { 16777216,		18455029,	18455027  },
+   { 33554432,		36911011,	36911009  },
+   { 67108864,		73819861,	73819859  },
+   { 134217728,		147639589,	147639587 },
+   { 268435456,		295279081,	295279079 },
+   { 536870912,		590559793,	590559791 },
+   { 1073741824,	1181116273,	1181116271},
+   { 2147483648ul,	2362232233ul,	2362232231ul}
+};
+
+static int
+entry_is_free(const struct hash_entry *entry)
+{
+   return entry->key == NULL;
+}
+
+static int
+entry_is_deleted(const struct hash_table *ht, struct hash_entry *entry)
+{
+   return entry->key == ht->deleted_key;
+}
+
+static int
+entry_is_present(const struct hash_table *ht, struct hash_entry *entry)
+{
+   return entry->key != NULL && entry->key != ht->deleted_key;
+}
+
+struct hash_table *
+_mesa_hash_table_create(void *mem_ctx,
+                        bool (*key_equals_function)(const void *a,
+                                                    const void *b))
+{
+   struct hash_table *ht;
+
+   ht = ralloc(mem_ctx, struct hash_table);
+   if (ht == NULL)
+      return NULL;
+
+   ht->size_index = 0;
+   ht->size = hash_sizes[ht->size_index].size;
+   ht->rehash = hash_sizes[ht->size_index].rehash;
+   ht->max_entries = hash_sizes[ht->size_index].max_entries;
+   ht->key_equals_function = key_equals_function;
+   ht->table = rzalloc_array(ht, struct hash_entry, ht->size);
+   ht->entries = 0;
+   ht->deleted_entries = 0;
+   ht->deleted_key = &deleted_key_value;
+
+   if (ht->table == NULL) {
+      ralloc_free(ht);
+      return NULL;
+   }
+
+   return ht;
+}
+
+/**
+ * Frees the given hash table.
+ *
+ * If delete_function is passed, it gets called on each entry present before
+ * freeing.
+ */
+void
+_mesa_hash_table_destroy(struct hash_table *ht,
+                         void (*delete_function)(struct hash_entry *entry))
+{
+   if (!ht)
+      return;
+
+   if (delete_function) {
+      struct hash_entry *entry;
+
+      hash_table_foreach(ht, entry) {
+         delete_function(entry);
+      }
+   }
+   ralloc_free(ht);
+}
+
+/** Sets the value of the key pointer used for deleted entries in the table.
+ *
+ * The assumption is that usually keys are actual pointers, so we use a
+ * default value of a pointer to an arbitrary piece of storage in the library.
+ * But in some cases a consumer wants to store some other sort of value in the
+ * table, like a uint32_t, in which case that pointer may conflict with one of
+ * their valid keys.  This lets that user select a safe value.
+ *
+ * This must be called before any keys are actually deleted from the table.
+ */
+void
+_mesa_hash_table_set_deleted_key(struct hash_table *ht, const void *deleted_key)
+{
+   ht->deleted_key = deleted_key;
+}
+
+/**
+ * Finds a hash table entry with the given key and hash of that key.
+ *
+ * Returns NULL if no entry is found.  Note that the data pointer may be
+ * modified by the user.
+ */
+struct hash_entry *
+_mesa_hash_table_search(struct hash_table *ht, uint32_t hash,
+                        const void *key)
+{
+   uint32_t start_hash_address = hash % ht->size;
+   uint32_t hash_address = start_hash_address;
+
+   do {
+      uint32_t double_hash;
+
+      struct hash_entry *entry = ht->table + hash_address;
+
+      if (entry_is_free(entry)) {
+         return NULL;
+      } else if (entry_is_present(ht, entry) && entry->hash == hash) {
+         if (ht->key_equals_function(key, entry->key)) {
+            return entry;
+         }
+      }
+
+      double_hash = 1 + hash % ht->rehash;
+
+      hash_address = (hash_address + double_hash) % ht->size;
+   } while (hash_address != start_hash_address);
+
+   return NULL;
+}
+
+static void
+_mesa_hash_table_rehash(struct hash_table *ht, int new_size_index)
+{
+   struct hash_table old_ht;
+   struct hash_entry *table, *entry;
+
+   if (new_size_index >= ARRAY_SIZE(hash_sizes))
+      return;
+
+   table = rzalloc_array(ht, struct hash_entry,
+                         hash_sizes[new_size_index].size);
+   if (table == NULL)
+      return;
+
+   old_ht = *ht;
+
+   ht->table = table;
+   ht->size_index = new_size_index;
+   ht->size = hash_sizes[ht->size_index].size;
+   ht->rehash = hash_sizes[ht->size_index].rehash;
+   ht->max_entries = hash_sizes[ht->size_index].max_entries;
+   ht->entries = 0;
+   ht->deleted_entries = 0;
+
+   hash_table_foreach(&old_ht, entry) {
+      _mesa_hash_table_insert(ht, entry->hash,
+                              entry->key, entry->data);
+   }
+
+   ralloc_free(old_ht.table);
+}
+
+/**
+ * Inserts the key with the given hash into the table.
+ *
+ * Note that insertion may rearrange the table on a resize or rehash,
+ * so previously found hash_entries are no longer valid after this function.
+ */
+struct hash_entry *
+_mesa_hash_table_insert(struct hash_table *ht, uint32_t hash,
+                        const void *key, void *data)
+{
+   uint32_t start_hash_address, hash_address;
+
+   if (ht->entries >= ht->max_entries) {
+      _mesa_hash_table_rehash(ht, ht->size_index + 1);
+   } else if (ht->deleted_entries + ht->entries >= ht->max_entries) {
+      _mesa_hash_table_rehash(ht, ht->size_index);
+   }
+
+   start_hash_address = hash % ht->size;
+   hash_address = start_hash_address;
+   do {
+      struct hash_entry *entry = ht->table + hash_address;
+      uint32_t double_hash;
+
+      if (!entry_is_present(ht, entry)) {
+         if (entry_is_deleted(ht, entry))
+            ht->deleted_entries--;
+         entry->hash = hash;
+         entry->key = key;
+         entry->data = data;
+         ht->entries++;
+         return entry;
+      }
+
+      /* Implement replacement when another insert happens
+       * with a matching key.  This is a relatively common
+       * feature of hash tables, with the alternative
+       * generally being "insert the new value as well, and
+       * return it first when the key is searched for".
+       *
+       * Note that the hash table doesn't have a delete
+       * callback.  If freeing of old data pointers is
+       * required to avoid memory leaks, perform a search
+       * before inserting.
+       */
+      if (entry->hash == hash &&
+          ht->key_equals_function(key, entry->key)) {
+         entry->key = key;
+         entry->data = data;
+         return entry;
+      }
+
+
+      double_hash = 1 + hash % ht->rehash;
+
+      hash_address = (hash_address + double_hash) % ht->size;
+   } while (hash_address != start_hash_address);
+
+   /* We could hit here if a required resize failed. An unchecked-malloc
+    * application could ignore this result.
+    */
+   return NULL;
+}
+
+/**
+ * This function deletes the given hash table entry.
+ *
+ * Note that deletion doesn't otherwise modify the table, so an iteration over
+ * the table deleting entries is safe.
+ */
+void
+_mesa_hash_table_remove(struct hash_table *ht,
+                        struct hash_entry *entry)
+{
+   if (!entry)
+      return;
+
+   entry->key = ht->deleted_key;
+   ht->entries--;
+   ht->deleted_entries++;
+}
+
+/**
+ * This function is an iterator over the hash table.
+ *
+ * Pass in NULL for the first entry, as in the start of a for loop.  Note that
+ * an iteration over the table is O(table_size) not O(entries).
+ */
+struct hash_entry *
+_mesa_hash_table_next_entry(struct hash_table *ht,
+                            struct hash_entry *entry)
+{
+   if (entry == NULL)
+      entry = ht->table;
+   else
+      entry = entry + 1;
+
+   for (; entry != ht->table + ht->size; entry++) {
+      if (entry_is_present(ht, entry)) {
+         return entry;
+      }
+   }
+
+   return NULL;
+}
+
+/**
+ * Returns a random entry from the hash table.
+ *
+ * This may be useful in implementing random replacement (as opposed
+ * to just removing everything) in caches based on this hash table
+ * implementation.  @predicate may be used to filter entries, or may
+ * be set to NULL for no filtering.
+ */
+struct hash_entry *
+_mesa_hash_table_random_entry(struct hash_table *ht,
+                              bool (*predicate)(struct hash_entry *entry))
+{
+   struct hash_entry *entry;
+   uint32_t i = rand() % ht->size;
+
+   if (ht->entries == 0)
+      return NULL;
+
+   for (entry = ht->table + i; entry != ht->table + ht->size; entry++) {
+      if (entry_is_present(ht, entry) &&
+          (!predicate || predicate(entry))) {
+         return entry;
+      }
+   }
+
+   for (entry = ht->table; entry != ht->table + i; entry++) {
+      if (entry_is_present(ht, entry) &&
+          (!predicate || predicate(entry))) {
+         return entry;
+      }
+   }
+
+   return NULL;
+}
+
+
+/**
+ * Quick FNV-1 hash implementation based on:
+ * http://www.isthe.com/chongo/tech/comp/fnv/
+ *
+ * FNV-1 is not be the best hash out there -- Jenkins's lookup3 is supposed to
+ * be quite good, and it probably beats FNV.  But FNV has the advantage that
+ * it involves almost no code.  For an improvement on both, see Paul
+ * Hsieh's http://www.azillionmonkeys.com/qed/hash.html
+ */
+uint32_t
+_mesa_hash_data(const void *data, size_t size)
+{
+   uint32_t hash = 2166136261ul;
+   const uint8_t *bytes = data;
+
+   while (size-- != 0) {
+      hash ^= *bytes;
+      hash = hash * 0x01000193;
+      bytes++;
+   }
+
+   return hash;
+}
+
+/** FNV-1 string hash implementation */
+uint32_t
+_mesa_hash_string(const char *key)
+{
+   uint32_t hash = 2166136261ul;
+
+   while (*key != 0) {
+      hash ^= *key;
+      hash = hash * 0x01000193;
+      key++;
+   }
+
+   return hash;
+}
+
+/**
+ * String compare function for use as the comparison callback in
+ * _mesa_hash_table_create().
+ */
+bool
+_mesa_key_string_equal(const void *a, const void *b)
+{
+   return strcmp(a, b) == 0;
+}
+
+bool
+_mesa_key_pointer_equal(const void *a, const void *b)
+{
+   return a == b;
+}