gpu/command_buffer/common/id_allocator.cc

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This file contains the implementation of IdAllocator.
   6
   7 #include "gpu/command_buffer/common/id_allocator.h"
   8 #include "gpu/command_buffer/common/logging.h"
   9
  10 namespace gpu {
  11
  12 IdAllocatorInterface::~IdAllocatorInterface() {
  13 }
  14
  15 IdAllocator::IdAllocator() {}
  16
  17 IdAllocator::~IdAllocator() {}
  18
  19 ResourceId IdAllocator::AllocateID() {
  20   ResourceId id;
  21   ResourceIdSet::iterator iter = free_ids_.begin();
  22   if (iter != free_ids_.end()) {
  23     id = *iter;
  24   } else {
  25     id = LastUsedId() + 1;
  26     if (!id) {
  27       // We wrapped around to 0.
  28       id = FindFirstUnusedId();
  29     }
  30   }
  31   MarkAsUsed(id);
  32   return id;
  33 }
  34
  35 ResourceId IdAllocator::AllocateIDAtOrAbove(ResourceId desired_id) {
  36   ResourceId id;
  37   ResourceIdSet::iterator iter = free_ids_.lower_bound(desired_id);
  38   if (iter != free_ids_.end()) {
  39     id = *iter;
  40   } else if (LastUsedId() < desired_id) {
  41     id = desired_id;
  42   } else {
  43     id = LastUsedId() + 1;
  44     if (!id) {
  45       // We wrapped around to 0.
  46       id = FindFirstUnusedId();
  47     }
  48   }
  49   MarkAsUsed(id);
  50   return id;
  51 }
  52
  53 bool IdAllocator::MarkAsUsed(ResourceId id) {
  54   GPU_DCHECK(id);
  55   free_ids_.erase(id);
  56   std::pair<ResourceIdSet::iterator, bool> result = used_ids_.insert(id);
  57   return result.second;
  58 }
  59
  60 void IdAllocator::FreeID(ResourceId id) {
  61   if (id) {
  62     used_ids_.erase(id);
  63     free_ids_.insert(id);
  64   }
  65 }
  66
  67 bool IdAllocator::InUse(ResourceId id) const {
  68   return id == kInvalidResource || used_ids_.find(id) != used_ids_.end();
  69 }
  70
  71 ResourceId IdAllocator::LastUsedId() const {
  72   if (used_ids_.empty()) {
  73     return 0u;
  74   } else {
  75     return *used_ids_.rbegin();
  76   }
  77 }
  78
  79 ResourceId IdAllocator::FindFirstUnusedId() const {
  80   ResourceId id = 1;
  81   for (ResourceIdSet::const_iterator it = used_ids_.begin();
  82        it != used_ids_.end(); ++it) {
  83     if ((*it) != id) {
  84       return id;
  85     }
  86     ++id;
  87   }
  88   return id;
  89 }
  90
  91 NonReusedIdAllocator::NonReusedIdAllocator() : last_id_(0) {
  92 }
  93
  94 NonReusedIdAllocator::~NonReusedIdAllocator() {
  95 }
  96
  97 ResourceId NonReusedIdAllocator::AllocateID() {
  98   return ++last_id_;
  99 }
 100
 101 ResourceId NonReusedIdAllocator::AllocateIDAtOrAbove(ResourceId desired_id) {
 102   if (desired_id > last_id_)
 103     last_id_ = desired_id;
 104
 105   return ++last_id_;
 106 }
 107
 108 bool NonReusedIdAllocator::MarkAsUsed(ResourceId id) {
 109   GPU_NOTREACHED();
 110   return false;
 111 }
 112
 113 void NonReusedIdAllocator::FreeID(ResourceId id) {
 114 }
 115
 116 bool NonReusedIdAllocator::InUse(ResourceId id) const {
 117   GPU_NOTREACHED();
 118   return false;
 119 }
 120
 121 }  // namespace gpu