vpx_mem/memory_manager/hmm_alloc.c

   1 /*
   2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11
  12 /* This code is in the public domain.
  13 ** Version: 1.1  Author: Walt Karas
  14 */
  15
  16 #include "hmm_intrnl.h"
  17
  18 void *U(alloc)(U(descriptor) *desc, U(size_aau) n)
  19 {
  20 #ifdef HMM_AUDIT_FAIL
  21
  22     if (desc->avl_tree_root)
  23         AUDIT_BLOCK(PTR_REC_TO_HEAD(desc->avl_tree_root))
  24 #endif
  25
  26         if (desc->last_freed)
  27         {
  28 #ifdef HMM_AUDIT_FAIL
  29             AUDIT_BLOCK(desc->last_freed)
  30 #endif
  31
  32             U(into_free_collection)(desc, (head_record *)(desc->last_freed));
  33
  34             desc->last_freed = 0;
  35         }
  36
  37     /* Add space for block header. */
  38     n += HEAD_AAUS;
  39
  40     /* Convert n from number of address alignment units to block alignment
  41     ** units. */
  42     n = DIV_ROUND_UP(n, HMM_BLOCK_ALIGN_UNIT);
  43
  44     if (n < MIN_BLOCK_BAUS)
  45         n = MIN_BLOCK_BAUS;
  46
  47     {
  48         /* Search for the first node of the bin containing the smallest
  49         ** block big enough to satisfy request. */
  50         ptr_record *ptr_rec_ptr =
  51             U(avl_search)(
  52                 (U(avl_avl) *) & (desc->avl_tree_root), (U(size_bau)) n,
  53                 AVL_GREATER_EQUAL);
  54
  55         /* If an approprate bin is found, satisfy the allocation request,
  56         ** otherwise return null pointer. */
  57         return(ptr_rec_ptr ?
  58                U(alloc_from_bin)(desc, ptr_rec_ptr, (U(size_bau)) n) : 0);
  59     }
  60 }