Motown: Rename Ratio and LinearFunction classes

mojo/services/media/common/cpp/ratio.h

-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef MOJO_SERVICES_MEDIA_COMMON_CPP_RATIO_H_
-#define MOJO_SERVICES_MEDIA_COMMON_CPP_RATIO_H_
-
-#include <stdint.h>
-
-#include <limits>
-
-#include "mojo/public/cpp/environment/logging.h"
-
-namespace mojo {
-namespace media {
-
-// TODO(dalesat): Consider always allowing inexact results.
-
-// Expresses a non-negative rational number as the ratio between two uint32_t
-// values.
-struct Ratio {
-  // Used to indicate overflow of scaling operations.
-  static constexpr int64_t kOverflow = std::numeric_limits<int64_t>::max();
-
-  // Reduces the ratio of *numerator and *denominator.
-  static void Reduce(uint32_t* numerator, uint32_t* denominator);
-
-  // Produces the product of the ratios. If exact is true, DCHECKs on loss of
-  // precision.
-  static void Product(uint32_t a_numerator,
-                      uint32_t a_denominator,
-                      uint32_t b_numerator,
-                      uint32_t b_denominator,
-                      uint32_t* product_numerator,
-                      uint32_t* product_denominator,
-                      bool exact = true);
-
-  // Produces the product of the ratios and the int64_t as an int64_t. Returns
-  // kOverflow on overflow.
-  static int64_t Scale(int64_t value, uint32_t numerator, uint32_t denominator);
-
-  // Returns the product of the ratios. If exact is true, DCHECKs on loss of
-  // precision.
-  static Ratio Product(const Ratio& a, const Ratio& b, bool exact = true) {
-    uint32_t result_numerator;
-    uint32_t result_denominator;
-    Product(a.numerator(), a.denominator(), b.numerator(), b.denominator(),
-            &result_numerator, &result_denominator, exact);
-    return Ratio(result_numerator, result_denominator);
-  }
-
-  Ratio() : numerator_(0), denominator_(1) {}
-
-  explicit Ratio(uint32_t numerator) : numerator_(numerator), denominator_(1) {}
-
-  Ratio(uint32_t numerator, uint32_t denominator)
-      : numerator_(numerator), denominator_(denominator) {
-    MOJO_DCHECK(denominator != 0);
-    Reduce(&numerator_, &denominator_);
-  }
-
-  // Returns the inverse of the ratio. DCHECKs if the numerator of this ratio
-  // is zero.
-  Ratio Inverse() const {
-    MOJO_DCHECK(numerator_ != 0);
-    return Ratio(denominator_, numerator_);
-  }
-
-  // Scales the value by this ratio. Returns kOverflow on overflow.
-  int64_t Scale(int64_t value) const {
-    return Scale(value, numerator_, denominator_);
-  }
-
-  uint32_t numerator() const { return numerator_; }
-  uint32_t denominator() const { return denominator_; }
-
- private:
-  uint32_t numerator_;
-  uint32_t denominator_;
-};
-
-// Tests two ratios for equality.
-inline bool operator==(const Ratio& a, const Ratio& b) {
-  return a.numerator() == b.numerator() && a.denominator() == b.denominator();
-}
-
-// Tests two ratios for inequality.
-inline bool operator!=(const Ratio& a, const Ratio& b) {
-  return !(a == b);
-}
-
-// Returns the product of the two ratios. DCHECKs on loss of precision.
-inline Ratio operator*(const Ratio& a, const Ratio& b) {
-  return Ratio::Product(a, b);
-}
-
-// Returns the product of the ratio and the int64_t. Returns kOverflow on
-// overflow.
-inline int64_t operator*(const Ratio& a, int64_t b) {
-  return a.Scale(b);
-}
-
-// Returns the product of the ratio and the int64_t. Returns kOverflow on
-// overflow.
-inline int64_t operator*(int64_t a, const Ratio& b) {
-  return b.Scale(a);
-}
-
-// Returns the the int64_t divided by the ratio. Returns kOverflow on
-// overflow.
-inline int64_t operator/(int64_t a, const Ratio& b) {
-  return b.Inverse().Scale(a);
-}
-
-}  // namespace media
-}  // namespace mojo
-
-#endif  // MOJO_SERVICES_MEDIA_COMMON_CPP_LINEAR_TRANSFORM_H_