Initial revision

1 files changed, 295 insertions, 0 deletions

diff --git a/src/mesa/main/hash.c b/src/mesa/main/hash.c
new file mode 100644
index 00000000000..3d533c82e8e
--- /dev/null
+++ b/src/mesa/main/hash.c
@@ -0,0 +1,295 @@
+/* $Id: hash.c,v 1.1 1999/08/19 00:55:41 jtg Exp $ */
+
+/*
+ * Mesa 3-D graphics library
+ * Version:  3.1
+ * 
+ * Copyright (C) 1999  Brian Paul   All Rights Reserved.
+ * 
+ * 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 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
+ * BRIAN PAUL 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.
+ */
+
+
+
+
+
+#ifdef PC_HEADER
+#include "all.h"
+#else
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "hash.h"
+#ifdef XFree86Server
+#include "GL/xf86glx.h"
+#endif
+#endif
+
+
+/*
+ * Generic hash table.  Only dependency is the GLuint datatype.
+ *
+ * This is used to implement display list and texture object lookup.
+ * NOTE: key=0 is illegal.
+ */
+
+
+#define TABLE_SIZE 1024
+
+struct HashEntry {
+   GLuint Key;
+   void *Data;
+   struct HashEntry *Next;
+};
+
+struct HashTable {
+   struct HashEntry *Table[TABLE_SIZE];
+   GLuint MaxKey;
+};
+
+
+
+/*
+ * Return pointer to a new, empty hash table.
+ */
+struct HashTable *NewHashTable(void)
+{
+   return (struct HashTable *) calloc(sizeof (struct HashTable), 1);
+}
+
+
+
+/*
+ * Delete a hash table.
+ */
+void DeleteHashTable(struct HashTable *table)
+{
+   GLuint i;
+   assert(table);
+   for (i=0;i<TABLE_SIZE;i++) {
+      struct HashEntry *entry = table->Table[i];
+      while (entry) {
+	 struct HashEntry *next = entry->Next;
+	 free(entry);
+	 entry = next;
+      }
+   }
+   free(table);
+}
+
+
+
+/*
+ * Lookup an entry in the hash table.
+ * Input:  table - the hash table
+ *         key - the key
+ * Return:  user data pointer or NULL if key not in table
+ */
+void *HashLookup(const struct HashTable *table, GLuint key)
+{
+   GLuint pos;
+   const struct HashEntry *entry;
+
+   assert(table);
+   assert(key);
+
+   pos = key & (TABLE_SIZE-1);
+   entry = table->Table[pos];
+   while (entry) {
+      if (entry->Key == key) {
+	 return entry->Data;
+      }
+      entry = entry->Next;
+   }
+   return NULL;
+}
+
+
+
+/*
+ * Insert into the hash table.  If an entry with this key already exists
+ * we'll replace the existing entry.
+ * Input:  table - the hash table
+ *         key - the key (not zero)
+ *         data - pointer to user data
+ */
+void HashInsert(struct HashTable *table, GLuint key, void *data)
+{
+   /* search for existing entry with this key */
+   GLuint pos;
+   struct HashEntry *entry;
+
+   assert(table);
+   assert(key);
+
+   if (key > table->MaxKey)
+      table->MaxKey = key;
+
+   pos = key & (TABLE_SIZE-1);
+   entry = table->Table[pos];
+   while (entry) {
+      if (entry->Key == key) {
+         /* replace entry's data */
+	 entry->Data = data;
+	 return;
+      }
+      entry = entry->Next;
+   }
+
+   /* alloc and insert new table entry */
+   entry = (struct HashEntry *) calloc(sizeof(struct HashEntry), 1);
+   entry->Key = key;
+   entry->Data = data;
+   entry->Next = table->Table[pos];
+   table->Table[pos] = entry;
+}
+
+
+
+/*
+ * Remove an entry from the hash table.
+ * Input:  table - the hash table
+ *         key - key of entry to remove
+ */
+void HashRemove(struct HashTable *table, GLuint key)
+{
+   GLuint pos;
+   struct HashEntry *entry, *prev;
+
+   assert(table);
+   assert(key);
+
+   pos = key & (TABLE_SIZE-1);
+   prev = NULL;
+   entry = table->Table[pos];
+   while (entry) {
+      if (entry->Key == key) {
+         /* found it! */
+         if (prev) {
+            prev->Next = entry->Next;
+         }
+         else {
+            table->Table[pos] = entry->Next;
+         }
+         free(entry);
+	 return;
+      }
+      prev = entry;
+      entry = entry->Next;
+   }
+}
+
+
+
+/*
+ * Return the key of the "first" entry in the hash table.
+ * By calling this function until zero is returned we can get
+ * the keys of all entries in the table.
+ */
+GLuint HashFirstEntry(const struct HashTable *table)
+{
+   GLuint pos;
+   assert(table);
+   for (pos=0; pos < TABLE_SIZE; pos++) {
+      if (table->Table[pos])
+         return table->Table[pos]->Key;
+   }
+   return 0;
+}
+
+
+
+/*
+ * Dump contents of hash table for debugging.
+ */
+void HashPrint(const struct HashTable *table)
+{
+   GLuint i;
+   assert(table);
+   for (i=0;i<TABLE_SIZE;i++) {
+      const struct HashEntry *entry = table->Table[i];
+      while (entry) {
+	 printf("%u %p\n", entry->Key, entry->Data);
+	 entry = entry->Next;
+      }
+   }
+}
+
+
+
+/*
+ * Find a block of 'numKeys' adjacent unused hash keys.
+ * Input:  table - the hash table
+ *         numKeys - number of keys needed
+ * Return:  startint key of free block or 0 if failure
+ */
+GLuint HashFindFreeKeyBlock(const struct HashTable *table, GLuint numKeys)
+{
+   GLuint maxKey = ~((GLuint) 0);
+   if (maxKey - numKeys > table->MaxKey) {
+      /* the quick solution */
+      return table->MaxKey + 1;
+   }
+   else {
+      /* the slow solution */
+      GLuint freeCount = 0;
+      GLuint freeStart = 0;
+      GLuint key;
+      for (key=0; key!=maxKey; key++) {
+	 if (HashLookup(table, key)) {
+	    /* darn, this key is already in use */
+	    freeCount = 0;
+	    freeStart = key+1;
+	 }
+	 else {
+	    /* this key not in use, check if we've found enough */
+	    freeCount++;
+	    if (freeCount == numKeys) {
+	       return freeStart;
+	    }
+	 }
+      }
+      /* cannot allocate a block of numKeys consecutive keys */
+      return 0;
+   }
+}
+
+
+
+#ifdef HASH_TEST_HARNESS
+int main(int argc, char *argv[])
+{
+   int a, b, c;
+   struct HashTable *t;
+
+   printf("&a = %p\n", &a);
+   printf("&b = %p\n", &b);
+
+   t = NewHashTable();
+   HashInsert(t, 501, &a);
+   HashInsert(t, 10, &c);
+   HashInsert(t, 0xfffffff8, &b);
+   HashPrint(t);
+   printf("Find 501: %p\n", HashLookup(t,501));
+   printf("Find 1313: %p\n", HashLookup(t,1313));
+   printf("Find block of 100: %d\n", HashFindFreeKeyBlock(t, 100));
+   DeleteHashTable(t);
+
+   return 0;
+}
+#endif