feat(clp-s): Add Timestamp schema tree node type to introduce the timestamp column; Add timestamp column reader and writer.

components/core/src/clp_s/ColumnReader.cpp

@@ -30,7 +30,7 @@ void DeltaEncodedInt64ColumnReader::load(BufferViewReader& reader, uint64_t num_
     }
 }
 
-int64_t DeltaEncodedInt64ColumnReader::get_value_at_idx(size_t idx) {
+auto DeltaEncodedInt64ColumnReader::get_value_at_idx(size_t idx) -> int64_t {
     if (m_cur_idx == idx) {
         return m_cur_value;
     }
@@ -253,4 +253,34 @@ void DateStringColumnReader::extract_string_value_into_buffer(
 epochtime_t DateStringColumnReader::get_encoded_time(uint64_t cur_message) {
     return m_timestamps[cur_message];
 }
+
+void TimestampColumnReader::load(BufferViewReader& reader, uint64_t num_messages) {
+    m_timestamps.load(reader, num_messages);
+    m_timestamp_encodings = reader.read_unaligned_span<uint64_t>(num_messages);
+}
+
+std::variant<int64_t, double, std::string, uint8_t> TimestampColumnReader::extract_value(
+        uint64_t cur_message
+) {
+    std::string ret;
+    m_timestamp_dict->append_timestamp_to_buffer(
+            m_timestamps.get_value_at_idx(cur_message),
+            m_timestamp_encodings[cur_message],
+            ret
+    );
+    return ret;
+}
+
+void
+TimestampColumnReader::extract_string_value_into_buffer(uint64_t cur_message, std::string& buffer) {
+    m_timestamp_dict->append_timestamp_to_buffer(
+            m_timestamps.get_value_at_idx(cur_message),
+            m_timestamp_encodings[cur_message],
+            buffer
+    );
+}
+
+auto TimestampColumnReader::get_encoded_time(uint64_t cur_message) -> epochtime_t {
+    return m_timestamps.get_value_at_idx(cur_message);
+}
 }  // namespace clp_s

components/core/src/clp_s/ColumnReader.hpp

@@ -113,15 +113,15 @@ class DeltaEncodedInt64ColumnReader : public BaseColumnReader {
 
     void extract_string_value_into_buffer(uint64_t cur_message, std::string& buffer) override;
 
-private:
     /**
      * Gets the value stored at a given index by summing up the stored deltas between the requested
      * index and the last requested index.
      * @param idx
      * @return The value stored at the requested index.
      */
-    int64_t get_value_at_idx(size_t idx);
+    [[nodiscard]] auto get_value_at_idx(size_t idx) -> int64_t;
 
+private:
     UnalignedMemSpan<int64_t> m_values;
     int64_t m_cur_value{};
     size_t m_cur_idx{};
@@ -360,6 +360,41 @@ class DateStringColumnReader : public BaseColumnReader {
     UnalignedMemSpan<int64_t> m_timestamps;
     UnalignedMemSpan<int64_t> m_timestamp_encodings;
 };
+
+class TimestampColumnReader : public BaseColumnReader {
+public:
+    // Constructor
+    TimestampColumnReader(int32_t id, std::shared_ptr<TimestampDictionaryReader> timestamp_dict)
+            : BaseColumnReader(id),
+              m_timestamp_dict(std::move(timestamp_dict)),
+              m_timestamps{id} {}
+
+    // Destructor
+    ~TimestampColumnReader() override = default;
+
+    // Methods inherited from BaseColumnReader
+    void load(BufferViewReader& reader, uint64_t num_messages) override;
+
+    NodeType get_type() override { return NodeType::Timestamp; }
+
+    std::variant<int64_t, double, std::string, uint8_t> extract_value(
+            uint64_t cur_message
+    ) override;
+
+    void extract_string_value_into_buffer(uint64_t cur_message, std::string& buffer) override;
+
+    /**
+     * @param cur_message
+     * @return The encoded time in epoch nanoseconds.
+     */
+    [[nodiscard]] auto get_encoded_time(uint64_t cur_message) -> epochtime_t;
+
+private:
+    std::shared_ptr<TimestampDictionaryReader> m_timestamp_dict;
+
+    DeltaEncodedInt64ColumnReader m_timestamps;
+    UnalignedMemSpan<uint64_t> m_timestamp_encodings;
+};
 }  // namespace clp_s
 
 #endif  // CLP_S_COLUMNREADER_HPP

components/core/src/clp_s/ColumnWriter.cpp

@@ -28,18 +28,21 @@ void Int64ColumnWriter::store(ZstdCompressor& compressor) {
     compressor.write(reinterpret_cast<char const*>(m_values.data()), size);
 }
 
-size_t DeltaEncodedInt64ColumnWriter::add_value(ParsedMessage::variable_t& value) {
+auto DeltaEncodedInt64ColumnWriter::add_value(int64_t value) -> size_t {
     if (0 == m_values.size()) {
-        m_cur = std::get<int64_t>(value);
-        m_values.push_back(m_cur);
+        m_cur = value;
+        m_values.emplace_back(m_cur);
     } else {
-        auto next = std::get<int64_t>(value);
-        m_values.push_back(next - m_cur);
-        m_cur = next;
+        m_values.emplace_back(value - m_cur);
+        m_cur = value;
     }
     return sizeof(int64_t);
 }
 
+size_t DeltaEncodedInt64ColumnWriter::add_value(ParsedMessage::variable_t& value) {
+    return add_value(std::get<int64_t>(value));
+}
+
 void DeltaEncodedInt64ColumnWriter::store(ZstdCompressor& compressor) {
     size_t size = m_values.size() * sizeof(int64_t);
     compressor.write(reinterpret_cast<char const*>(m_values.data()), size);
@@ -181,4 +184,17 @@ void DateStringColumnWriter::store(ZstdCompressor& compressor) {
     size_t encodings_size = m_timestamp_encodings.size() * sizeof(int64_t);
     compressor.write(reinterpret_cast<char const*>(m_timestamp_encodings.data()), encodings_size);
 }
+
+auto TimestampColumnWriter::add_value(ParsedMessage::variable_t& value) -> size_t {
+    auto const& encoded_timestamp = std::get<std::pair<epochtime_t, uint64_t>>(value);
+    auto const encoded_timestamp_size{m_timestamps.add_value(encoded_timestamp.first)};
+    m_timestamp_encodings.emplace_back(encoded_timestamp.second);
+    return encoded_timestamp_size + sizeof(uint64_t);
+}
+
+void TimestampColumnWriter::store(ZstdCompressor& compressor) {
+    m_timestamps.store(compressor);
+    size_t const encodings_size{m_timestamp_encodings.size() * sizeof(uint64_t)};
+    compressor.write(reinterpret_cast<char const*>(m_timestamp_encodings.data()), encodings_size);
+}
 }  // namespace clp_s

components/core/src/clp_s/ColumnWriter.hpp

@@ -72,6 +72,9 @@ class DeltaEncodedInt64ColumnWriter : public BaseColumnWriter {
     // Destructor
     ~DeltaEncodedInt64ColumnWriter() override = default;
 
+    // Methods
+    [[nodiscard]] auto add_value(int64_t value) -> size_t;
+
     // Methods inherited from BaseColumnWriter
     size_t add_value(ParsedMessage::variable_t& value) override;
 
@@ -256,6 +259,24 @@ class DateStringColumnWriter : public BaseColumnWriter {
     std::vector<int64_t> m_timestamps;
     std::vector<int64_t> m_timestamp_encodings;
 };
+
+class TimestampColumnWriter : public BaseColumnWriter {
+public:
+    // Constructor
+    explicit TimestampColumnWriter(int32_t id) : BaseColumnWriter(id), m_timestamps{id} {}
+
+    // Destructor
+    ~TimestampColumnWriter() override = default;
+
+    // Methods inherited from BaseColumnWriter
+    auto add_value(ParsedMessage::variable_t& value) -> size_t override;
+
+    void store(ZstdCompressor& compressor) override;
+
+private:
+    DeltaEncodedInt64ColumnWriter m_timestamps;
+    std::vector<uint64_t> m_timestamp_encodings;
+};
 }  // namespace clp_s
 
 #endif  // CLP_S_COLUMNWRITER_HPP

components/core/src/clp_s/ParsedMessage.hpp

@@ -24,6 +24,7 @@ class ParsedMessage {
                     clp::ffi::FourByteEncodedTextAst,
                     bool,
                     std::pair<uint64_t, epochtime_t>,
+                    std::pair<epochtime_t, uint64_t>,
                     std::pair<double, float_format_t>>;
 
     // Constructor

components/core/src/clp_s/SchemaTree.hpp

@@ -44,6 +44,7 @@ enum class NodeType : uint8_t {
     DeltaInteger,
     FormattedFloat,
     DictionaryFloat,
+    Timestamp,
     Unknown = std::underlying_type<NodeType>::type(~0ULL)
 };
 

components/core/src/clp_s/TimestampDictionaryReader.hpp

@@ -36,6 +36,21 @@ class TimestampDictionaryReader {
      */
     std::string get_string_encoding(epochtime_t epoch, uint64_t format_id) const;
 
+    /**
+     * Marshals and appends the `timestamp` to the `buffer` by interpreting the timestamp pattern
+     * referenced by `format_id` as a `clp_s::timestamp_parser::TimestampPattern`.
+     * @param timestamp
+     * @param format_id
+     * @param buffer
+     * @throws OperationFailed if the format indicated by `format_id` can not be interpreted as a
+     * `clp_s::timestamp_parser::TimestampPattern`.
+     */
+    void append_timestamp_to_buffer(
+            epochtime_t timestamp,
+            uint64_t format_id,
+            std::string& buffer
+    ) const { /*NO-OP until follow-up PR*/ }
+
     /**
      * Gets iterators for the timestamp patterns
      * @return begin and end iterators for the timestamp patterns