1 // Copyright (c) 2012 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.
5 // This file contains the definition of the IdAllocator class.
7 #ifndef GPU_COMMAND_BUFFER_CLIENT_ID_ALLOCATOR_H_
8 #define GPU_COMMAND_BUFFER_CLIENT_ID_ALLOCATOR_H_
15 #include "base/compiler_specific.h"
16 #include "base/macros.h"
17 #include "gpu/gpu_export.h"
21 // A resource ID, key to the resource maps.
22 typedef uint32_t ResourceId
;
23 // Invalid resource ID.
24 static const ResourceId kInvalidResource
= 0u;
26 class GPU_EXPORT IdAllocatorInterface
{
28 virtual ~IdAllocatorInterface();
30 // Allocates a new resource ID.
31 virtual ResourceId
AllocateID() = 0;
33 // Allocates an Id starting at or above desired_id.
34 // Note: may wrap if it starts near limit.
35 virtual ResourceId
AllocateIDAtOrAbove(ResourceId desired_id
) = 0;
37 // Marks an id as used. Returns false if id was already used.
38 virtual bool MarkAsUsed(ResourceId id
) = 0;
40 // Frees a resource ID.
41 virtual void FreeID(ResourceId id
) = 0;
43 // Checks whether or not a resource ID is in use.
44 virtual bool InUse(ResourceId id
) const = 0;
47 // A class to manage the allocation of resource IDs.
48 class GPU_EXPORT IdAllocator
: public IdAllocatorInterface
{
51 virtual ~IdAllocator();
53 // Implement IdAllocatorInterface.
54 virtual ResourceId
AllocateID() OVERRIDE
;
55 virtual ResourceId
AllocateIDAtOrAbove(ResourceId desired_id
) OVERRIDE
;
56 virtual bool MarkAsUsed(ResourceId id
) OVERRIDE
;
57 virtual void FreeID(ResourceId id
) OVERRIDE
;
58 virtual bool InUse(ResourceId id
) const OVERRIDE
;
61 // TODO(gman): This would work much better with ranges or a hash table.
62 typedef std::set
<ResourceId
> ResourceIdSet
;
64 // The highest ID on the used list.
65 ResourceId
LastUsedId() const;
67 // Lowest ID that isn't on the used list. This is slow, use as a last resort.
68 ResourceId
FindFirstUnusedId() const;
70 ResourceIdSet used_ids_
;
71 ResourceIdSet free_ids_
;
73 DISALLOW_COPY_AND_ASSIGN(IdAllocator
);
76 // A class to manage the allocation of resource IDs that are never reused. This
77 // implementation does not track which IDs are currently used. It is useful for
78 // shared and programs which cannot be implicitly created by binding a
79 // previously unused ID.
80 class NonReusedIdAllocator
: public IdAllocatorInterface
{
82 NonReusedIdAllocator();
83 virtual ~NonReusedIdAllocator();
85 // Implement IdAllocatorInterface.
86 virtual ResourceId
AllocateID() OVERRIDE
;
87 virtual ResourceId
AllocateIDAtOrAbove(ResourceId desired_id
) OVERRIDE
;
88 virtual bool MarkAsUsed(ResourceId id
) OVERRIDE
;
89 virtual void FreeID(ResourceId id
) OVERRIDE
;
90 virtual bool InUse(ResourceId id
) const OVERRIDE
;
95 DISALLOW_COPY_AND_ASSIGN(NonReusedIdAllocator
);
100 #endif // GPU_COMMAND_BUFFER_CLIENT_ID_ALLOCATOR_H_