1 files changed, 90 insertions, 0 deletions
diff --git a/pw_fuzzer/examples/fuzztest/metrics.h b/pw_fuzzer/examples/fuzztest/metrics.h
new file mode 100644
index 000000000..9026ffa71
--- /dev/null
+++ b/pw_fuzzer/examples/fuzztest/metrics.h
@@ -0,0 +1,90 @@
+// Copyright 2020 The Pigweed 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
+//
+//     https://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.
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <functional>
+#include <optional>
+#include <span>
+#include <string_view>
+
+#include "pw_bytes/span.h"
+#include "pw_containers/vector.h"
+#include "pw_status/status.h"
+#include "pw_status/status_with_size.h"
+#include "pw_string/string.h"
+
+namespace pw::fuzzer::examples {
+
+// DOCSTAG: [pwfuzzer_examples_fuzztest-metrics_h]
+// Represent a named value. In order to transmit these values efficiently, they
+// can be referenced by fixed length, generated keys instead of names.
+struct Metric {
+  using Key = uint16_t;
+  using Value = uint32_t;
+
+  static constexpr size_t kMaxNameLen = 32;
+
+  Metric() = default;
+  Metric(std::string_view name_, Value value_);
+
+  InlineString<kMaxNameLen> name;
+  Key key = 0;
+  Value value = 0;
+};
+
+// Represents a set of measurements from a particular source.
+//
+// In order to transmit metrics efficiently, the names of metrics are hashed
+// internally into fixed length keys. The names can be shared once via `GetKeys`
+// and `SetKeys`, after which metrics can be efficiently shared via `Serialize`
+// and `Deserialize`.
+class Metrics {
+ public:
+  static constexpr size_t kMaxMetrics = 32;
+  static constexpr size_t kMaxSerializedSize =
+      sizeof(size_t) +
+      kMaxMetrics * (sizeof(Metric::Key) + sizeof(Metric::Value));
+
+  // Retrieves the value of a named metric and stores it in `out_value`. The
+  // name must consist of printable ASCII characters. Returns false if the named
+  // metric was not `Set` or `Import`ed.
+  std::optional<Metric::Value> GetValue(std::string_view name) const;
+
+  // Sets the value of a named metric. The name must consist of printable ASCII
+  // characters, and will be added to the mapping of names to keys.
+  Status SetValue(std::string_view name, Metric::Value value);
+
+  // Returns the current mapping of names to keys.
+  const Vector<Metric>& GetMetrics() const;
+
+  // Replaces the current mapping of names to keys.
+  Status SetMetrics(const Vector<Metric>& metrics);
+
+  // Serializes this object to the given `buffer`. Does not write more bytes
+  // than `buffer.size()`. Returns the number of number of bytes written or an
+  // error if insufficient space.
+  StatusWithSize Serialize(pw::ByteSpan buffer) const;
+
+  // Populates this object from the data in the given `buffer`.
+  // Returns whether this buffer could be deserialized.
+  Status Deserialize(pw::ConstByteSpan buffer);
+
+ private:
+  Vector<Metric, kMaxMetrics> metrics_;
+};
+// DOCSTAG: [pwfuzzer_examples_fuzztest-metrics_h]
+
+}  // namespace pw::fuzzer::examples