util: Move main/set to util/hash_set

Reviewed-by: Matt Turner <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>

1 files changed, 345 insertions, 0 deletions

diff --git a/src/util/set.c b/src/util/set.c
new file mode 100644
index 00000000000..3f4a4acb2ce
--- /dev/null
+++ b/src/util/set.c
@@ -0,0 +1,345 @@
+/*
+ * 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]>
+ */
+
+#include <stdlib.h>
+
+#include "macros.h"
+#include "ralloc.h"
+#include "set.h"
+
+/*
+ * 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
+ */
+
+uint32_t deleted_key_value;
+const void *deleted_key = &deleted_key_value;
+
+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(struct set_entry *entry)
+{
+   return entry->key == NULL;
+}
+
+static int
+entry_is_deleted(struct set_entry *entry)
+{
+   return entry->key == deleted_key;
+}
+
+static int
+entry_is_present(struct set_entry *entry)
+{
+   return entry->key != NULL && entry->key != deleted_key;
+}
+
+struct set *
+_mesa_set_create(void *mem_ctx,
+                 bool (*key_equals_function)(const void *a,
+                                             const void *b))
+{
+   struct set *ht;
+
+   ht = ralloc(mem_ctx, struct set);
+   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 set_entry, ht->size);
+   ht->entries = 0;
+   ht->deleted_entries = 0;
+
+   if (ht->table == NULL) {
+      ralloc_free(ht);
+      return NULL;
+   }
+
+   return ht;
+}
+
+/**
+ * Frees the given set.
+ *
+ * If delete_function is passed, it gets called on each entry present before
+ * freeing.
+ */
+void
+_mesa_set_destroy(struct set *ht, void (*delete_function)(struct set_entry *entry))
+{
+   if (!ht)
+      return;
+
+   if (delete_function) {
+      struct set_entry *entry;
+
+      set_foreach (ht, entry) {
+         delete_function(entry);
+      }
+   }
+   ralloc_free(ht->table);
+   ralloc_free(ht);
+}
+
+/**
+ * Finds a set entry with the given key and hash of that key.
+ *
+ * Returns NULL if no entry is found.
+ */
+struct set_entry *
+_mesa_set_search(const struct set *ht, uint32_t hash, const void *key)
+{
+   uint32_t hash_address;
+
+   hash_address = hash % ht->size;
+   do {
+      uint32_t double_hash;
+
+      struct set_entry *entry = ht->table + hash_address;
+
+      if (entry_is_free(entry)) {
+         return NULL;
+      } else if (entry_is_present(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 != hash % ht->size);
+
+   return NULL;
+}
+
+static void
+set_rehash(struct set *ht, int new_size_index)
+{
+   struct set old_ht;
+   struct set_entry *table, *entry;
+
+   if (new_size_index >= ARRAY_SIZE(hash_sizes))
+      return;
+
+   table = rzalloc_array(ht, struct set_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;
+
+   for (entry = old_ht.table;
+        entry != old_ht.table + old_ht.size;
+        entry++) {
+      if (entry_is_present(entry)) {
+         _mesa_set_add(ht, entry->hash, entry->key);
+      }
+   }
+
+   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 set_entry *
+_mesa_set_add(struct set *ht, uint32_t hash, const void *key)
+{
+   uint32_t hash_address;
+
+   if (ht->entries >= ht->max_entries) {
+      set_rehash(ht, ht->size_index + 1);
+   } else if (ht->deleted_entries + ht->entries >= ht->max_entries) {
+      set_rehash(ht, ht->size_index);
+   }
+
+   hash_address = hash % ht->size;
+   do {
+      struct set_entry *entry = ht->table + hash_address;
+      uint32_t double_hash;
+
+      if (!entry_is_present(entry)) {
+         if (entry_is_deleted(entry))
+            ht->deleted_entries--;
+         entry->hash = hash;
+         entry->key = key;
+         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 keys 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;
+         return entry;
+      }
+
+      double_hash = 1 + hash % ht->rehash;
+
+      hash_address = (hash_address + double_hash) % ht->size;
+   } while (hash_address != hash % ht->size);
+
+   /* 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_set_remove(struct set *ht, struct set_entry *entry)
+{
+   if (!entry)
+      return;
+
+   entry->key = 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 set_entry *
+_mesa_set_next_entry(const struct set *ht, struct set_entry *entry)
+{
+   if (entry == NULL)
+      entry = ht->table;
+   else
+      entry = entry + 1;
+
+   for (; entry != ht->table + ht->size; entry++) {
+      if (entry_is_present(entry)) {
+         return entry;
+      }
+   }
+
+   return NULL;
+}
+
+struct set_entry *
+_mesa_set_random_entry(struct set *ht,
+                       int (*predicate)(struct set_entry *entry))
+{
+   struct set_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(entry) &&
+          (!predicate || predicate(entry))) {
+         return entry;
+      }
+   }
+
+   for (entry = ht->table; entry != ht->table + i; entry++) {
+      if (entry_is_present(entry) &&
+          (!predicate || predicate(entry))) {
+         return entry;
+      }
+   }
+
+   return NULL;
+}