ui/gfx/geometry/safe_integer_conversions.h

   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.
   4
   5 #ifndef UI_GFX_GEOMETRY_SAFE_INTEGER_CONVERSIONS_H_
   6 #define UI_GFX_GEOMETRY_SAFE_INTEGER_CONVERSIONS_H_
   7
   8 #include <cmath>
   9 #include <limits>
  10
  11 #include "ui/gfx/gfx_export.h"
  12
  13 namespace gfx {
  14
  15 inline int ClampToInt(float value) {
  16   if (value != value)
  17     return 0; // no int NaN.
  18   if (value >= std::numeric_limits<int>::max())
  19     return std::numeric_limits<int>::max();
  20   if (value <= std::numeric_limits<int>::min())
  21     return std::numeric_limits<int>::min();
  22   return static_cast<int>(value);
  23 }
  24
  25 inline int ToFlooredInt(float value) {
  26   return ClampToInt(std::floor(value));
  27 }
  28
  29 inline int ToCeiledInt(float value) {
  30   return ClampToInt(std::ceil(value));
  31 }
  32
  33 inline int ToFlooredInt(double value) {
  34   return ClampToInt(std::floor(value));
  35 }
  36
  37 inline int ToCeiledInt(double value) {
  38   return ClampToInt(std::ceil(value));
  39 }
  40
  41 inline int ToRoundedInt(float value) {
  42   float rounded;
  43   if (value >= 0.0f)
  44     rounded = std::floor(value + 0.5f);
  45   else
  46     rounded = std::ceil(value - 0.5f);
  47   return ClampToInt(rounded);
  48 }
  49
  50 inline int ToRoundedInt(double value) {
  51   double rounded;
  52   if (value >= 0.0)
  53     rounded = std::floor(value + 0.5);
  54   else
  55     rounded = std::ceil(value - 0.5);
  56   return ClampToInt(rounded);
  57 }
  58
  59 inline bool IsExpressibleAsInt(float value) {
  60   if (value != value)
  61     return false; // no int NaN.
  62   if (value > std::numeric_limits<int>::max())
  63     return false;
  64   if (value < std::numeric_limits<int>::min())
  65     return false;
  66   return true;
  67 }
  68
  69 }  // namespace gfx
  70
  71 #endif  // UI_GFX_GEOMETRY_SAFE_INTEGER_CONVERSIONS_H_