cc/resources/shared_bitmap.cc

   1 // Copyright 2013 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 #include "cc/resources/shared_bitmap.h"
   6
   7 #include "base/logging.h"
   8 #include "base/numerics/safe_math.h"
   9 #include "base/rand_util.h"
  10
  11 namespace cc {
  12
  13 SharedBitmap::SharedBitmap(
  14     base::SharedMemory* memory,
  15     const SharedBitmapId& id,
  16     const base::Callback<void(SharedBitmap* bitmap)>& free_callback)
  17     : memory_(memory),
  18       pixels_(static_cast<uint8*>(memory_->memory())),
  19       id_(id),
  20       free_callback_(free_callback) {
  21 }
  22
  23 SharedBitmap::SharedBitmap(
  24     uint8* pixels,
  25     const SharedBitmapId& id,
  26     const base::Callback<void(SharedBitmap* bitmap)>& free_callback)
  27     : memory_(NULL), pixels_(pixels), id_(id), free_callback_(free_callback) {
  28 }
  29
  30 SharedBitmap::~SharedBitmap() { free_callback_.Run(this); }
  31
  32 // static
  33 bool SharedBitmap::SizeInBytes(const gfx::Size& size, size_t* size_in_bytes) {
  34   if (size.IsEmpty())
  35     return false;
  36   base::CheckedNumeric<size_t> s = 4;
  37   s *= size.width();
  38   s *= size.height();
  39   if (!s.IsValid())
  40     return false;
  41   *size_in_bytes = s.ValueOrDie();
  42   return true;
  43 }
  44
  45 // static
  46 size_t SharedBitmap::CheckedSizeInBytes(const gfx::Size& size) {
  47   CHECK(!size.IsEmpty());
  48   base::CheckedNumeric<size_t> s = 4;
  49   s *= size.width();
  50   s *= size.height();
  51   return s.ValueOrDie();
  52 }
  53
  54 // static
  55 size_t SharedBitmap::UncheckedSizeInBytes(const gfx::Size& size) {
  56   DCHECK(VerifySizeInBytes(size));
  57   size_t s = 4;
  58   s *= size.width();
  59   s *= size.height();
  60   return s;
  61 }
  62
  63 // static
  64 bool SharedBitmap::VerifySizeInBytes(const gfx::Size& size) {
  65   if (size.IsEmpty())
  66     return false;
  67   base::CheckedNumeric<size_t> s = 4;
  68   s *= size.width();
  69   s *= size.height();
  70   return s.IsValid();
  71 }
  72
  73 // static
  74 SharedBitmapId SharedBitmap::GenerateId() {
  75   SharedBitmapId id;
  76   // Needs cryptographically-secure random numbers.
  77   base::RandBytes(id.name, sizeof(id.name));
  78   return id;
  79 }
  80
  81 }  // namespace cc