pw_protobuf: Support encoding packed bool fields

Change-Id: I21b0f2b82f8761afa94216cebfa7ef7c4fe6e0d6
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/88962
Pigweed-Auto-Submit: Scott James Remnant <keybuk@google.com>
Reviewed-by: Armando Montanez <amontanez@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>

5 files changed, 73 insertions, 4 deletions

diff --git a/pw_protobuf/codegen_encoder_test.cc b/pw_protobuf/codegen_encoder_test.cc
index 6c0866bc9..2787681e3 100644
--- a/pw_protobuf/codegen_encoder_test.cc
+++ b/pw_protobuf/codegen_encoder_test.cc
@@ -320,6 +320,29 @@ TEST(CodegenRepeated, PackedScalar) {
             0);
 }
 
+TEST(CodegenRepeated, PackedBool) {
+  std::byte encode_buffer[32];
+
+  stream::MemoryWriter writer(encode_buffer);
+  RepeatedTest::StreamEncoder repeated_test(writer, ByteSpan());
+  constexpr bool values[] = {true, false, true, true, false};
+  repeated_test.WriteBools(std::span(values))
+      .IgnoreError();  // TODO(pwbug/387): Handle Status properly
+
+  // clang-format off
+  constexpr uint8_t expected_proto[] = {
+    // bools[], v={true, false, true, true, false}
+    0x3a, 0x05, 0x01, 0x00, 0x01, 0x01, 0x00,
+  };
+  // clang-format on
+
+  ConstByteSpan result = writer.WrittenData();
+  ASSERT_EQ(repeated_test.status(), OkStatus());
+  EXPECT_EQ(result.size(), sizeof(expected_proto));
+  EXPECT_EQ(std::memcmp(result.data(), expected_proto, sizeof(expected_proto)),
+            0);
+}
+
 TEST(CodegenRepeated, NonScalar) {
   std::byte encode_buffer[32];
 
diff --git a/pw_protobuf/encoder_test.cc b/pw_protobuf/encoder_test.cc
index 1ab005aca..3c01c5570 100644
--- a/pw_protobuf/encoder_test.cc
+++ b/pw_protobuf/encoder_test.cc
@@ -307,6 +307,26 @@ TEST(StreamEncoder, PackedVarintInsufficientSpace) {
   EXPECT_EQ(encoder.status(), Status::ResourceExhausted());
 }
 
+TEST(StreamEncoder, PackedBool) {
+  std::byte encode_buffer[32];
+  MemoryEncoder encoder(encode_buffer);
+
+  // repeated bool values = 1;
+  constexpr bool values[] = {true, false, true, true, false};
+  encoder.WritePackedBool(1, values)
+      .IgnoreError();  // TODO(pwbug/387): Handle Status properly
+
+  constexpr uint8_t encoded_proto[] = {
+      0x0a, 0x05, 0x01, 0x00, 0x01, 0x01, 0x00};
+  //  key   size  v[0]  v[1]  v[2]  v[3]  v[4]
+
+  ASSERT_EQ(encoder.status(), OkStatus());
+  ConstByteSpan result(encoder);
+  EXPECT_EQ(result.size(), sizeof(encoded_proto));
+  EXPECT_EQ(std::memcmp(result.data(), encoded_proto, sizeof(encoded_proto)),
+            0);
+}
+
 TEST(StreamEncoder, PackedFixed) {
   std::byte encode_buffer[32];
   MemoryEncoder encoder(encode_buffer);
diff --git a/pw_protobuf/public/pw_protobuf/encoder.h b/pw_protobuf/public/pw_protobuf/encoder.h
index c3d68ad6b..41117db28 100644
--- a/pw_protobuf/public/pw_protobuf/encoder.h
+++ b/pw_protobuf/public/pw_protobuf/encoder.h
@@ -275,6 +275,19 @@ class StreamEncoder {
     return WriteUint32(field_number, static_cast<uint32_t>(value));
   }
 
+  // Writes a repeated bool using packed encoding.
+  //
+  // Precondition: Encoder has no active child encoder.
+  Status WritePackedBool(uint32_t field_number, std::span<const bool> values) {
+    static_assert(sizeof(bool) == sizeof(uint8_t),
+                  "bool must be same size as uint8_t");
+    return WritePackedVarints(
+        field_number,
+        std::span(reinterpret_cast<const uint8_t*>(values.data()),
+                  values.size()),
+        VarintEncodeType::kNormal);
+  }
+
   // Writes a proto fixed32 key-value pair.
   //
   // Precondition: Encoder has no active child encoder.
@@ -531,12 +544,13 @@ class StreamEncoder {
   Status WritePackedVarints(uint32_t field_number,
                             std::span<T> values,
                             VarintEncodeType encode_type) {
-    static_assert(std::is_same<T, const uint32_t>::value ||
+    static_assert(std::is_same<T, const uint8_t>::value ||
+                      std::is_same<T, const uint32_t>::value ||
                       std::is_same<T, const int32_t>::value ||
                       std::is_same<T, const uint64_t>::value ||
                       std::is_same<T, const int64_t>::value,
-                  "Packed varints must be of type uint32_t, int32_t, uint64_t, "
-                  "or int64_t");
+                  "Packed varints must be of type bool, uint32_t, int32_t, "
+                  "uint64_t, or int64_t");
 
     size_t payload_size = 0;
     for (T val : values) {
diff --git a/pw_protobuf/pw_protobuf_test_protos/repeated.proto b/pw_protobuf/pw_protobuf_test_protos/repeated.proto
index 49fbbd204..590d2e00c 100644
--- a/pw_protobuf/pw_protobuf_test_protos/repeated.proto
+++ b/pw_protobuf/pw_protobuf_test_protos/repeated.proto
@@ -22,6 +22,7 @@ message RepeatedTest {
   repeated double doubles = 4;
   repeated Struct structs = 5;
   repeated fixed32 fixed32s = 6;
+  repeated bool bools = 7;
 };
 
 message Struct {
diff --git a/pw_protobuf/py/pw_protobuf/codegen_pwpb.py b/pw_protobuf/py/pw_protobuf/codegen_pwpb.py
index a7ef3cab0..ae54bd88f 100644
--- a/pw_protobuf/py/pw_protobuf/codegen_pwpb.py
+++ b/pw_protobuf/py/pw_protobuf/codegen_pwpb.py
@@ -929,6 +929,15 @@ class BoolWriteMethod(WriteMethod):
         return 'WriteBool'
 
 
+class PackedBoolWriteMethod(PackedWriteMethod):
+    """Method which writes a packed list of bools."""
+    def params(self) -> List[Tuple[str, str]]:
+        return [('std::span<const bool>', 'values')]
+
+    def _encoder_fn(self) -> str:
+        return 'WritePackedBool'
+
+
 class BoolReadMethod(ReadMethod):
     """Method which reads a proto bool value."""
     def _result_type(self) -> str:
@@ -1061,7 +1070,9 @@ PROTO_FIELD_WRITE_METHODS: Dict[int, List] = {
     [Uint64WriteMethod, PackedUint64WriteMethod],
     descriptor_pb2.FieldDescriptorProto.TYPE_FIXED64:
     [Fixed64WriteMethod, PackedFixed64WriteMethod],
-    descriptor_pb2.FieldDescriptorProto.TYPE_BOOL: [BoolWriteMethod],
+    descriptor_pb2.FieldDescriptorProto.TYPE_BOOL: [
+        BoolWriteMethod, PackedBoolWriteMethod
+    ],
     descriptor_pb2.FieldDescriptorProto.TYPE_BYTES: [BytesWriteMethod],
     descriptor_pb2.FieldDescriptorProto.TYPE_STRING: [
         StringLenWriteMethod, StringWriteMethod