Index: content/common/inter_process_time_ticks_converter.cc |
diff --git a/content/common/inter_process_time_ticks_converter.cc b/content/common/inter_process_time_ticks_converter.cc |
new file mode 100644 |
index 0000000000000000000000000000000000000000..09c14f0ec62585df5631076dfed515745bfefe92 |
--- /dev/null |
+++ b/content/common/inter_process_time_ticks_converter.cc |
@@ -0,0 +1,58 @@ |
+// Copyright (c) 2011 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. |
+ |
+#include "content/common/inter_process_time_ticks_converter.h" |
+ |
+#include "base/logging.h" |
+ |
+namespace content { |
+ |
+InterProcessTimeTicksConverter::InterProcessTimeTicksConverter( |
+ const LocalTimeTicks& local_lower_bound, |
+ const LocalTimeTicks& local_upper_bound, |
+ const RemoteTimeTicks& remote_lower_bound, |
+ const RemoteTimeTicks& remote_upper_bound) |
+ : remote_lower_bound_(remote_lower_bound.value_), |
+ remote_upper_bound_(remote_upper_bound.value_) { |
+ int64 target_range = local_upper_bound.value_ - local_lower_bound.value_; |
+ int64 source_range = remote_upper_bound.value_ - remote_lower_bound.value_; |
+ if (source_range <= target_range) { |
+ // We fit! Just shift the midpoints to match. |
+ numerator_ = 1; |
+ denominator_ = 1; |
+ offset_ = ((local_upper_bound.value_ + local_lower_bound.value_) - |
+ (remote_upper_bound.value_ + remote_lower_bound.value_)) / 2; |
+ return; |
+ } |
+ // Set up scaling factors, and then deduce shift. |
+ numerator_ = target_range; |
+ denominator_ = source_range; |
+ // Find out what we need to shift by to make this really work. |
+ offset_ = local_lower_bound.value_ - Convert(remote_lower_bound.value_); |
+ DCHECK_GE(local_upper_bound.value_, Convert(remote_upper_bound.value_)); |
+} |
+ |
+LocalTimeTicks InterProcessTimeTicksConverter::ToLocalTimeTicks( |
+ const RemoteTimeTicks& remote_ms) { |
+ DCHECK_LE(remote_lower_bound_, remote_ms.value_); |
+ DCHECK_GE(remote_upper_bound_, remote_ms.value_); |
+ RemoteTimeDelta remote_delta = remote_ms - remote_lower_bound_; |
+ return LocalTimeTicks(remote_lower_bound_ + offset_ + |
+ ToLocalTimeDelta(remote_delta).value_); |
+} |
+ |
+LocalTimeDelta InterProcessTimeTicksConverter::ToLocalTimeDelta( |
+ const RemoteTimeDelta& remote_delta) { |
+ DCHECK_GE(remote_upper_bound_, remote_lower_bound_ + remote_delta.value_); |
+ return LocalTimeDelta(Convert(remote_delta.value_)); |
+} |
+ |
+int64 InterProcessTimeTicksConverter::Convert(int64 value) { |
+ if (value <= 0) { |
+ return value; |
+ } |
+ return numerator_ * value / denominator_; |
+} |
+ |
+} // namespace content |