gpu/command_buffer/common/mailbox.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 "gpu/command_buffer/common/mailbox.h"
   6
   7 #include <string.h>
   8
   9 #include "base/logging.h"
  10 #include "base/rand_util.h"
  11
  12 namespace gpu {
  13
  14 Mailbox::Mailbox() {
  15   memset(name, 0, sizeof(name));
  16 }
  17
  18 bool Mailbox::IsZero() const {
  19   for (size_t i = 0; i < arraysize(name); ++i) {
  20     if (name[i])
  21       return false;
  22   }
  23   return true;
  24 }
  25
  26 void Mailbox::SetZero() {
  27   memset(name, 0, sizeof(name));
  28 }
  29
  30 void Mailbox::SetName(const int8* n) {
  31   DCHECK(IsZero() || !memcmp(name, n, sizeof(name)));
  32   memcpy(name, n, sizeof(name));
  33 }
  34
  35 Mailbox Mailbox::Generate() {
  36   Mailbox result;
  37   // Generates cryptographically-secure bytes.
  38   base::RandBytes(result.name, sizeof(result.name));
  39 #if !defined(NDEBUG)
  40   int8 value = 1;
  41   for (size_t i = 1; i < sizeof(result.name); ++i)
  42     value ^= result.name[i];
  43   result.name[0] = value;
  44 #endif
  45   return result;
  46 }
  47
  48 bool Mailbox::Verify() const {
  49 #if !defined(NDEBUG)
  50   int8 value = 1;
  51   for (size_t i = 0; i < sizeof(name); ++i)
  52     value ^= name[i];
  53   return value == 0;
  54 #else
  55   return true;
  56 #endif
  57 }
  58
  59 }  // namespace gpu