src/mesa/program/prog_cache.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28
  29 #include "main/glheader.h"
  30 #include "main/mtypes.h"
  31 #include "main/imports.h"
  32 #include "program/prog_cache.h"
  33 #include "program/program.h"
  34
  35
  36 struct cache_item
  37 {
  38    GLuint hash;
  39    void *key;
  40    struct gl_program *program;
  41    struct cache_item *next;
  42 };
  43
  44 struct gl_program_cache
  45 {
  46    struct cache_item **items;
  47    struct cache_item *last;
  48    GLuint size, n_items;
  49 };
  50
  51
  52
  53 /**
  54  * Compute hash index from state key.
  55  */
  56 static GLuint
  57 hash_key(const void *key, GLuint key_size)
  58 {
  59    const GLuint *ikey = (const GLuint *) key;
  60    GLuint hash = 0, i;
  61
  62    assert(key_size >= 4);
  63
  64    /* Make a slightly better attempt at a hash function:
  65     */
  66    for (i = 0; i < key_size / sizeof(*ikey); i++)
  67    {
  68       hash += ikey[i];
  69       hash += (hash << 10);
  70       hash ^= (hash >> 6);
  71    }
  72
  73    return hash;
  74 }
  75
  76
  77 /**
  78  * Rebuild/expand the hash table to accomodate more entries
  79  */
  80 static void
  81 rehash(struct gl_program_cache *cache)
  82 {
  83    struct cache_item **items;
  84    struct cache_item *c, *next;
  85    GLuint size, i;
  86
  87    cache->last = NULL;
  88
  89    size = cache->size * 3;
  90    items = (struct cache_item**) malloc(size * sizeof(*items));
  91    memset(items, 0, size * sizeof(*items));
  92
  93    for (i = 0; i < cache->size; i++)
  94       for (c = cache->items[i]; c; c = next) {
  95          next = c->next;
  96          c->next = items[c->hash % size];
  97          items[c->hash % size] = c;
  98       }
  99
 100    free(cache->items);
 101    cache->items = items;
 102    cache->size = size;
 103 }
 104
 105
 106 static void
 107 clear_cache(struct gl_context *ctx, struct gl_program_cache *cache)
 108 {
 109    struct cache_item *c, *next;
 110    GLuint i;
 111
 112    cache->last = NULL;
 113
 114    for (i = 0; i < cache->size; i++) {
 115       for (c = cache->items[i]; c; c = next) {
 116          next = c->next;
 117          free(c->key);
 118          _mesa_reference_program(ctx, &c->program, NULL);
 119          free(c);
 120       }
 121       cache->items[i] = NULL;
 122    }
 123
 124
 125    cache->n_items = 0;
 126 }
 127
 128
 129
 130 struct gl_program_cache *
 131 _mesa_new_program_cache(void)
 132 {
 133    struct gl_program_cache *cache = CALLOC_STRUCT(gl_program_cache);
 134    if (cache) {
 135       cache->size = 17;
 136       cache->items = (struct cache_item **)
 137          calloc(1, cache->size * sizeof(struct cache_item));
 138       if (!cache->items) {
 139          free(cache);
 140          return NULL;
 141       }
 142    }
 143    return cache;
 144 }
 145
 146
 147 void
 148 _mesa_delete_program_cache(struct gl_context *ctx, struct gl_program_cache *cache)
 149 {
 150    clear_cache(ctx, cache);
 151    free(cache->items);
 152    free(cache);
 153 }
 154
 155
 156 struct gl_program *
 157 _mesa_search_program_cache(struct gl_program_cache *cache,
 158                            const void *key, GLuint keysize)
 159 {
 160    if (cache->last &&
 161        memcmp(cache->last->key, key, keysize) == 0) {
 162       return cache->last->program;
 163    }
 164    else {
 165       const GLuint hash = hash_key(key, keysize);
 166       struct cache_item *c;
 167
 168       for (c = cache->items[hash % cache->size]; c; c = c->next) {
 169          if (c->hash == hash && memcmp(c->key, key, keysize) == 0) {
 170             cache->last = c;
 171             return c->program;
 172          }
 173       }
 174
 175       return NULL;
 176    }
 177 }
 178
 179
 180 void
 181 _mesa_program_cache_insert(struct gl_context *ctx,
 182                            struct gl_program_cache *cache,
 183                            const void *key, GLuint keysize,
 184                            struct gl_program *program)
 185 {
 186    const GLuint hash = hash_key(key, keysize);
 187    struct cache_item *c = CALLOC_STRUCT(cache_item);
 188
 189    c->hash = hash;
 190
 191    c->key = malloc(keysize);
 192    memcpy(c->key, key, keysize);
 193
 194    c->program = program;  /* no refcount change */
 195
 196    if (cache->n_items > cache->size * 1.5) {
 197       if (cache->size < 1000)
 198          rehash(cache);
 199       else
 200          clear_cache(ctx, cache);
 201    }
 202
 203    cache->n_items++;
 204    c->next = cache->items[hash % cache->size];
 205    cache->items[hash % cache->size] = c;
 206 }