Add functions to parse an input history record

The code will take a 5 byte raw record that comes from
the power supply and create an instance of a Record
out of it.  A Record includes the average and maximum
power values, the sequence ID, and a timestamp.

Change-Id: I9dec5fd3de2ae2c6275a1407bcec4717557ffe86
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/power-supply/record_manager.cpp b/power-supply/record_manager.cpp
index 7492dd3..1fcd463 100644
--- a/power-supply/record_manager.cpp
+++ b/power-supply/record_manager.cpp
@@ -13,7 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+#include <chrono>
 #include <math.h>
+#include <phosphor-logging/log.hpp>
 #include "record_manager.hpp"
 
 namespace witherspoon
@@ -23,6 +25,44 @@
 namespace history
 {
 
+using namespace phosphor::logging;
+
+size_t RecordManager::getRawRecordID(
+        const std::vector<uint8_t>& data) const
+{
+    if (data.size() != RAW_RECORD_SIZE)
+    {
+        log<level::ERR>("Invalid INPUT_HISTORY size",
+                entry("SIZE=%d", data.size()));
+        throw InvalidRecordException{};
+    }
+
+    return data[RAW_RECORD_ID_OFFSET];
+}
+
+Record RecordManager::createRecord(const std::vector<uint8_t>& data)
+{
+    //The raw record format is:
+    //  0xAABBCCDDEE
+    //
+    //  where:
+    //    0xAA = sequence ID
+    //    0xBBCC = average power in linear format (0xCC = MSB)
+    //    0xDDEE = maximum power in linear format (0xEE = MSB)
+    auto id = getRawRecordID(data);
+
+    auto time = std::chrono::duration_cast<std::chrono::milliseconds>(
+            std::chrono::system_clock::now().time_since_epoch()).count();
+
+    auto val = static_cast<uint16_t>(data[2]) << 8 | data[1];
+    auto averagePower = linearToInteger(val);
+
+    val = static_cast<uint16_t>(data[4]) << 8 | data[3];
+    auto maxPower = linearToInteger(val);
+
+    return Record{id, time, averagePower, maxPower};
+}
+
 int64_t RecordManager::linearToInteger(uint16_t data)
 {
     //The exponent is the first 5 bits, followed by 11 bits of mantissa.