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PiperOrigin-RevId: 253489161

mediapipe/framework/timestamp.cc

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+// Copyright 2019 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "mediapipe/framework/timestamp.h"
+
+#include <string>
+
+#include "absl/strings/str_cat.h"
+
+namespace mediapipe {
+
+constexpr double Timestamp::kTimestampUnitsPerSecond;
+
+// In the following functions:
+// - The safe int type will check for overflow/underflow and other errors.
+// - The CHECK in the constructor will disallow special values.
+TimestampDiff Timestamp::operator-(const Timestamp other) const {
+  CHECK(IsRangeValue() && other.IsRangeValue())
+      << "This timestamp is " << DebugString() << " and other was "
+      << other.DebugString();
+  TimestampBaseType tmp_base = timestamp_ - other.timestamp_;
+  return TimestampDiff(tmp_base);
+}
+TimestampDiff TimestampDiff::operator+(const TimestampDiff other) const {
+  TimestampBaseType tmp_base = timestamp_ + other.timestamp_;
+  return TimestampDiff(tmp_base);
+}
+TimestampDiff TimestampDiff::operator-(const TimestampDiff other) const {
+  TimestampBaseType tmp_base = timestamp_ - other.timestamp_;
+  return TimestampDiff(tmp_base);
+}
+
+// Clamp the addition to the range [Timestamp::Min(), Timestamp::Max()].
+Timestamp Timestamp::operator+(const TimestampDiff offset) const {
+  CHECK(IsRangeValue()) << "Timestamp is: " << DebugString();
+  TimestampBaseType offset_base(offset.Value());
+  if (offset_base >= TimestampBaseType(0)) {
+    if (timestamp_.value() >= Timestamp::Max().Value() - offset_base.value()) {
+      // We would overflow.
+      return Timestamp::Max();
+    }
+  }
+  if (offset_base <= TimestampBaseType(0)) {
+    if (timestamp_.value() <= Timestamp::Min().Value() - offset_base.value()) {
+      // We would underflow.
+      return Timestamp::Min();
+    }
+  }
+  return Timestamp(timestamp_ + offset_base);
+}
+Timestamp Timestamp::operator-(const TimestampDiff offset) const {
+  return *this + -offset;
+}
+Timestamp TimestampDiff::operator+(const Timestamp timestamp) const {
+  return timestamp + *this;
+}
+
+Timestamp Timestamp::operator+=(const TimestampDiff other) {
+  *this = *this + other;
+  return *this;
+}
+Timestamp Timestamp::operator-=(const TimestampDiff other) {
+  *this = *this - other;
+  return *this;
+}
+Timestamp Timestamp::operator++() {
+  *this += 1;
+  return *this;
+}
+Timestamp Timestamp::operator--() {
+  *this -= 1;
+  return *this;
+}
+Timestamp Timestamp::operator++(int /*unused*/) {
+  Timestamp previous(*this);
+  ++(*this);
+  return previous;
+}
+Timestamp Timestamp::operator--(int /*unused*/) {
+  Timestamp previous(*this);
+  --(*this);
+  return previous;
+}
+
+std::string Timestamp::DebugString() const {
+  if (IsSpecialValue()) {
+    if (*this == Timestamp::Unset()) {
+      return "Timestamp::Unset()";
+    } else if (*this == Timestamp::Unstarted()) {
+      return "Timestamp::Unstarted()";
+    } else if (*this == Timestamp::PreStream()) {
+      return "Timestamp::PreStream()";
+    } else if (*this == Timestamp::Min()) {
+      return "Timestamp::Min()";
+    } else if (*this == Timestamp::Max()) {
+      return "Timestamp::Max()";
+    } else if (*this == Timestamp::PostStream()) {
+      return "Timestamp::PostStream()";
+    } else if (*this == Timestamp::OneOverPostStream()) {
+      return "Timestamp::OneOverPostStream()";
+    } else if (*this == Timestamp::Done()) {
+      return "Timestamp::Done()";
+    } else {
+      LOG(FATAL) << "Unknown special type.";
+    }
+  }
+  return absl::StrCat(timestamp_.value());
+}
+std::string TimestampDiff::DebugString() const {
+  return absl::StrCat(timestamp_.value());
+}
+
+Timestamp Timestamp::NextAllowedInStream() const {
+  CHECK(IsAllowedInStream()) << "Timestamp is: " << DebugString();
+  if (IsRangeValue() && *this != Max()) {
+    return *this + 1;
+  } else {
+    // Returning this value effectively means no futher timestamps may
+    // occur (however, the stream is not yet closed).
+    return OneOverPostStream();
+  }
+}
+
+std::ostream& operator<<(std::ostream& os, Timestamp arg) {
+  return os << arg.DebugString();
+}
+std::ostream& operator<<(std::ostream& os, TimestampDiff arg) {
+  return os << arg.DebugString();
+}
+
+}  // namespace mediapipe