1 // Copyright (c) 2011 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 "content/common/inter_process_time_ticks_converter.h" 6 7 #include "base/logging.h" 8 #include "base/strings/string_number_conversions.h" 9 10 namespace content { 11 12 InterProcessTimeTicksConverter::InterProcessTimeTicksConverter( 13 const LocalTimeTicks& local_lower_bound, 14 const LocalTimeTicks& local_upper_bound, 15 const RemoteTimeTicks& remote_lower_bound, 16 const RemoteTimeTicks& remote_upper_bound) 17 : remote_lower_bound_(remote_lower_bound.value_), 18 remote_upper_bound_(remote_upper_bound.value_) { 19 int64 target_range = local_upper_bound.value_ - local_lower_bound.value_; 20 int64 source_range = remote_upper_bound.value_ - remote_lower_bound.value_; 21 DCHECK_GE(target_range, 0); 22 DCHECK_GE(source_range, 0); 23 if (source_range <= target_range) { 24 // We fit! Center the source range on the target range. 25 numerator_ = 1; 26 denominator_ = 1; 27 local_base_time_ = 28 local_lower_bound.value_ + (target_range - source_range) / 2; 29 // When converting times, remote bounds should fall within local bounds. 30 DCHECK_LE(local_lower_bound.value_, 31 ToLocalTimeTicks(remote_lower_bound).value_); 32 DCHECK_GE(local_upper_bound.value_, 33 ToLocalTimeTicks(remote_upper_bound).value_); 34 return; 35 } 36 37 // Interpolate values so that remote range will be will exactly fit into the 38 // local range, if possible. 39 numerator_ = target_range; 40 denominator_ = source_range; 41 local_base_time_ = local_lower_bound.value_; 42 // When converting times, remote bounds should equal local bounds. 43 DCHECK_EQ(local_lower_bound.value_, 44 ToLocalTimeTicks(remote_lower_bound).value_); 45 DCHECK_EQ(local_upper_bound.value_, 46 ToLocalTimeTicks(remote_upper_bound).value_); 47 DCHECK_EQ(target_range, Convert(source_range)); 48 } 49 50 LocalTimeTicks InterProcessTimeTicksConverter::ToLocalTimeTicks( 51 const RemoteTimeTicks& remote_ms) const { 52 // If input time is "null", return another "null" time. 53 if (remote_ms.value_ == 0) 54 return LocalTimeTicks(0); 55 DCHECK_LE(remote_lower_bound_, remote_ms.value_); 56 DCHECK_GE(remote_upper_bound_, remote_ms.value_); 57 RemoteTimeDelta remote_delta = remote_ms - remote_lower_bound_; 58 return LocalTimeTicks(local_base_time_ + 59 ToLocalTimeDelta(remote_delta).value_); 60 } 61 62 LocalTimeDelta InterProcessTimeTicksConverter::ToLocalTimeDelta( 63 const RemoteTimeDelta& remote_delta) const { 64 DCHECK_GE(remote_upper_bound_, remote_lower_bound_ + remote_delta.value_); 65 return LocalTimeDelta(Convert(remote_delta.value_)); 66 } 67 68 int64 InterProcessTimeTicksConverter::Convert(int64 value) const { 69 if (value <= 0) { 70 return value; 71 } 72 return numerator_ * value / denominator_; 73 } 74 75 } // namespace content 76
