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(uint8* pixels, const SharedBitmapId& id)
  14     : pixels_(pixels), id_(id) {
  15 }
  16
  17 SharedBitmap::~SharedBitmap() {
  18 }
  19
  20 // static
  21 bool SharedBitmap::SizeInBytes(const gfx::Size& size, size_t* size_in_bytes) {
  22   if (size.IsEmpty())
  23     return false;
  24   base::CheckedNumeric<size_t> s = 4;
  25   s *= size.width();
  26   s *= size.height();
  27   if (!s.IsValid())
  28     return false;
  29   *size_in_bytes = s.ValueOrDie();
  30   return true;
  31 }
  32
  33 // static
  34 size_t SharedBitmap::CheckedSizeInBytes(const gfx::Size& size) {
  35   CHECK(!size.IsEmpty());
  36   base::CheckedNumeric<size_t> s = 4;
  37   s *= size.width();
  38   s *= size.height();
  39   return s.ValueOrDie();
  40 }
  41
  42 // static
  43 size_t SharedBitmap::UncheckedSizeInBytes(const gfx::Size& size) {
  44   DCHECK(VerifySizeInBytes(size));
  45   size_t s = 4;
  46   s *= size.width();
  47   s *= size.height();
  48   return s;
  49 }
  50
  51 // static
  52 bool SharedBitmap::VerifySizeInBytes(const gfx::Size& size) {
  53   if (size.IsEmpty())
  54     return false;
  55   base::CheckedNumeric<size_t> s = 4;
  56   s *= size.width();
  57   s *= size.height();
  58   return s.IsValid();
  59 }
  60
  61 // static
  62 SharedBitmapId SharedBitmap::GenerateId() {
  63   SharedBitmapId id;
  64   // Needs cryptographically-secure random numbers.
  65   base::RandBytes(id.name, sizeof(id.name));
  66   return id;
  67 }
  68
  69 }  // namespace cc