PEL: Add PEL class

This class represents a Platform Event Log.

A PEL consists of sections, and this commit just adds support for the
only required sections - the Private Header and User Header, by
including those specific objects.  More will be added in the future.

The only constructor provided in this commit is to construct the object
from an existing flattened PEL buffer.  This is for use in the case when
a PEL is received from off the BMC, such as from the host.  Future
commits will add support for creating PELs from OpenBMC event logs.

Since there aren't objects yet for every PEL section, the class cannot
make a full flattened PEL without still keeping around the original PEL
data it received in the constructor as mentioned above.  So for now it
will keep that data and just overlay the sections it does support when
flattening.  In the future, a fully formed PEL will be able to be
constructed from just flattening the section objects in the correct
order.

This commit provides a few public methods of note:

* data() - returns a flattened PEL
* assignID() - sets a unique ID in the log ID field in the Private
               Header
* setCommitTime() - Sets the commit timestamp in the Private Header
                    to the current time
* valid() - Says if the PEL is properly formed

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I2a9d82df9cd096ce77ecca7b2f73b097b8368aa2
diff --git a/extensions/openpower-pels/pel.hpp b/extensions/openpower-pels/pel.hpp
new file mode 100644
index 0000000..564fe33
--- /dev/null
+++ b/extensions/openpower-pels/pel.hpp
@@ -0,0 +1,204 @@
+#pragma once
+
+#include "private_header.hpp"
+#include "user_header.hpp"
+
+#include <memory>
+#include <vector>
+
+namespace openpower
+{
+namespace pels
+{
+
+/** @class PEL
+ *
+ * @brief This class represents a specific event log format referred to as a
+ * Platform Event Log.
+ *
+ * Every field in a PEL are in structures call sections, of which there are
+ * several types.  Some sections are required, and some are optional.  In some
+ * cases there may be more than one instance of a section type.
+ *
+ * The only two required sections for every type of PEL are the Private Header
+ * section and User Header section, which must be in the first and second
+ * positions, respectively.
+ *
+ * Every section starts with an 8 byte section header, which has the section
+ * size and type, among other things.
+ *
+ * This class represents all sections with objects.
+ *
+ * The available constructors are:
+ * - PEL(const std::vector<uint8_t>& data) - build this object out of a fully
+ *   formed flattened PEL.
+ *
+ * The data() method allows one to retrieve the PEL as a vector<uint8_t>.  This
+ * is the format in which it is stored and transmitted.
+ */
+class PEL
+{
+  public:
+    PEL() = delete;
+    ~PEL() = default;
+    PEL(const PEL&) = delete;
+    PEL& operator=(const PEL&) = delete;
+    PEL(PEL&&) = delete;
+    PEL& operator=(PEL&&) = delete;
+
+    /**
+     * @brief Constructor
+     *
+     * Build a PEL from raw data.
+     *
+     * @param[in] data - The PEL data
+     */
+    PEL(const std::vector<uint8_t>& data);
+
+    /**
+     * @brief Constructor
+     *
+     * Build a PEL from the raw data.
+     *
+     * @param[in] data - the PEL data
+     * @param[in] obmcLogID - the corresponding OpenBMC event log ID
+     */
+    PEL(const std::vector<uint8_t>& data, uint32_t obmcLogID);
+
+    /**
+     * @brief Convenience function to return the log ID field from the
+     *        Private Header section.
+     *
+     * @return uint32_t - the ID
+     */
+    uint32_t id() const
+    {
+        return _ph->id();
+    }
+
+    /**
+     * @brief Convenience function to return the PLID field from the
+     *        Private Header section.
+     *
+     * @return uint32_t - the PLID
+     */
+    uint32_t plid() const
+    {
+        return _ph->plid();
+    }
+
+    /**
+     * @brief Convenience function to return the OpenBMC event log ID field
+     * from the Private Header section.
+     *
+     * @return uint32_t - the OpenBMC event log ID
+     */
+    uint32_t obmcLogID() const
+    {
+        return _ph->obmcLogID();
+    }
+
+    /**
+     * @brief Convenience function to return the commit time field from
+     *        the Private Header section.
+     *
+     * @return BCDTime - the timestamp
+     */
+    BCDTime commitTime() const
+    {
+        return _ph->commitTimestamp();
+    }
+
+    /**
+     * @brief Convenience function to return the create time field from
+     *        the Private Header section.
+     *
+     * @return BCDTime - the timestamp
+     */
+    BCDTime createTime() const
+    {
+        return _ph->createTimestamp();
+    }
+
+    /**
+     * @brief Gives access to the Private Header section class
+     *
+     * @return std::unique_ptr<PrivateHeader>& the private header
+     */
+    std::unique_ptr<PrivateHeader>& privateHeader()
+    {
+        return _ph;
+    }
+
+    /**
+     * @brief Gives access to the User Header section class
+     *
+     * @return std::unique_ptr<UserHeader>& the user header
+     */
+    std::unique_ptr<UserHeader>& userHeader()
+    {
+        return _uh;
+    }
+
+    /**
+     * @brief Returns the PEL data.
+     *
+     * @return std::vector<uint8_t> - the raw PEL data
+     */
+    std::vector<uint8_t> data();
+
+    /**
+     * @brief Says if the PEL is valid (the sections are all valid)
+     *
+     * @return bool - if the PEL is valid
+     */
+    bool valid() const;
+
+    /**
+     * @brief Sets the commit timestamp to the current time
+     */
+    void setCommitTime();
+
+    /**
+     * @brief Sets the error log ID field to a unique ID.
+     */
+    void assignID();
+
+  private:
+    /**
+     * @brief Builds the section objects from a PEL data buffer
+     *
+     * @param[in] obmcLogID - The OpenBMC event log ID to use for that
+     *                        field in the Private Header.
+     */
+    void populateFromRawData(uint32_t obmcLogID);
+
+    /**
+     * @brief Flattens the PEL objects into the buffer
+     *
+     * @param[out] pelBuffer - What the data will be written to
+     */
+    void flatten(std::vector<uint8_t>& pelBuffer);
+
+    /**
+     * @brief The PEL Private Header section
+     */
+    std::unique_ptr<PrivateHeader> _ph;
+
+    /**
+     * @brief The PEL User Header section
+     */
+    std::unique_ptr<UserHeader> _uh;
+
+    /**
+     * @brief The PEL itself.
+     *
+     * This should be able to be removed when this class is able to
+     * serialize/deserialize a complete PEL from its objects, as
+     * then there will be no need to keep around the data anymore.
+     */
+    std::vector<uint8_t> _rawPEL;
+};
+
+} // namespace pels
+} // namespace openpower