payload encoding optimized to minimize size by replacing float by sint32 and int32 by uint32 were possible guided by experimental data

Author: MAKOMO

src/proto/artisan_roast.proto

@@ -36,46 +36,46 @@ message Roast {
   //
   // - all indices of the given milestones are valid and strict monotonic
   //   milestone_idicies = [
-  //      milestones.charge_idx,
-  //      milestones.dry_end_idx,
-  //      milestones.first_crack_start_idx,
-  //      milestones.first_crack_end_idx,
-  //      milestones.second_crack_start_idx,
-  //      milestones.second_crack_end_idx,
-  //      milestones.drop_idx
+  //       milestones.charge_idx,
+  //       milestones.dry_end_idx,
+  //       milestones.first_crack_start_idx,
+  //       milestones.first_crack_end_idx,
+  //       milestones.second_crack_start_idx,
+  //       milestones.second_crack_end_idx,
+  //       milestones.drop_idx
   //   ]
   //   for i, idx in enumerate(milestone_idicies):
-  //     if hasValue(idx):
-  //         0 <= idx < len(times) and
-  //         for 0 <= j < i:
-  //         if hasValue(milestone_idicies[j]
-  //            milestone_idicies[j] < idx
+  //       if HasField(idx):
+  //           0 <= idx < len(times) and
+  //           for 0 <= j < i:
+  //               if HasField(milestone_idicies[j]
+  //                  milestone_idicies[j] < idx
   // - all annotations are well defined and valid
   //   len(annotations.time_indices) == len(annotations.tags) and
   //   for idx in annotations.time_indices: 0 <= idx < len(times)
   // - all events are well defined and valid
   //   for events in {events1, events2, events3, events4}:
-  //     len(events.time_indices) == len(events.values) and
-  //     for idx in events.time_indices: 0 <= idx <= len(times)
-  // - all readings are valid
+  //       len(events.time_indices) == len(events.values) and
+  //       for idx in events.time_indices: 0 <= idx <= len(times)
+  // - all readings are valid (every reading has an associated time)
   //   for readings in {
   //          bt_values, et_values,
-  //          bt_ror_values, et_ror_values}:
-  //      len(readings) == len(time)
+  //          bt_ror_values, et_ror_values}
+  //       len(readings) <= len(times)
   //   for curve in additional_curves:
-  //       len(curve.values) == len(times)
+  //       len(curve.values) <= len(times)
   // - time is monotonic
   //   for i in range(0,len(times)):
-  //      for 0 <= j < i:
-  //         times[j] <= times[i]
+  //       for 0 <= j < i:
+  //           times[j] <= times[i]
   // - time of CHARGE (start of roast)
-  //   if hasValue(milestones) and hasValue(milestones.charge_idx):
-  //      times[milestones.charge_idx] = 0
+  //   if HasField(milestones) and HasField(milestones.charge_idx):
+  //       times[milestones.charge_idx] == 0
   //   elif len(times)>0:
-  //      times[0] = 0
+  //       times[0] == 0
   //   NOTE: time[x]=0 corresponds to timestamp 'start'
   // - time of DROP (end of roast)
-  //   if hasValue(milestones) and hasValue(milestones.drop_idx):
+  //   if HasField(milestones) and HasField(milestones.drop_idx):
   //       times[milestones.drop_idx]
   //       NOTE: times[milestones.drop_idx] corresponds
   //             to timestamp 'drop'
@@ -85,45 +85,46 @@ message Roast {
   //             to timestamp 'drop'
 
   message Milestones {
-    int32 charge_idx = 1;
-    int32 dry_end_idx = 2;
-    int32 first_crack_start_idx = 3;
-    int32 first_crack_end_idx = 4;
-    int32 second_crack_start_idx = 5;
-    int32 second_crack_end_idx = 6;
-    int32 drop_idx = 7;
+    uint32 charge_idx = 1;
+    uint32 dry_end_idx = 2;
+    uint32 first_crack_start_idx = 3;
+    uint32 first_crack_end_idx = 4;
+    uint32 second_crack_start_idx = 5;
+    uint32 second_crack_end_idx = 6;
+    uint32 drop_idx = 7;
   }
 
   message Annotations {
-    repeated int32 time_indices = 1;
+    repeated uint32 time_indices = 1;
     repeated string tags = 2;
   }
 
   message Events {
     string name = 1;
     string unit = 2;
-    repeated int32 time_indices = 3;
-    repeated int32 values = 4;
+    repeated uint32 time_indices = 3;
+    repeated uint32 values = 4;
   }
 
   message Curve {
     string name = 1;
-    repeated float values = 2;
-    bool temperatures = 3;
+    repeated sint32 values = 2; // readings multiplied by 10
+    bool temperatures = 3;      // true if values are temperatures in C
   }
 
   string org_id = 1;           // id of organization
   string machine_id = 2;       // id of machine
   string roast_id = 3;         // roast UUID
   google.protobuf.Timestamp start = 4;   // start of roast
   google.protobuf.Timestamp end = 5;     // end of roast
-  repeated float times = 6;    // [s] roast time relative to CHARGE
+  repeated sint32 times = 6;   // [s] roast time relative to CHARGE
   Milestones milestones = 7;   // main roasting events like CHARGE, FCs, ...
   Annotations annotations = 8; // text annotations
   repeated Events events = 9;  // events like power changes
-  repeated float bt_values = 10;  // [Celsius] bean temperatures
-  repeated float et_values = 11;  // [Celsius] environmental temperatures
-  repeated float bt_ror_values = 12;     // [Celsius/min] BT RoR
-  repeated float et_ror_values = 13;     // [Celsius/min] ET RoR
-  repeated Curve additional_curves = 14; // additional curves
+  repeated sint32 bt_values = 10; // [C] bean temperatures multiplied by 10
+  repeated sint32 et_values = 11; // [C] environmental temperatures mult. by 10
+  repeated sint32 bt_ror_values = 12;     // [C/min] BT RoR multiplied by 10
+  repeated sint32 et_ror_values = 13;     // [C/min] ET RoR multiplied by 10
+  repeated Curve additional_curves = 14;  // additional curves
+  uint32 factor = 15;  // multiplication factor of all values
 }