feat(rtps, cdr): Add cdr and rtps components

.github/workflows/build.yml

@@ -53,6 +53,8 @@ jobs:
           target: esp32s3
         - path: 'components/chsc6x/example'
           target: esp32s3
+        - path: 'components/cdr/example'
+          target: esp32
         - path: 'components/cli/example'
           target: esp32
         - path: 'components/cobs/example'
@@ -177,6 +179,8 @@ jobs:
           target: esp32s3
         - path: 'components/rmt/example'
           target: esp32s3
+        - path: 'components/rtps/example'
+          target: esp32
         - path: 'components/rtsp/example'
           target: esp32
         - path: 'components/runqueue/example'

.github/workflows/upload_components.yml

@@ -47,6 +47,7 @@ jobs:
             components/button
             components/byte90
             components/chsc6x
+            components/cdr
             components/cli
             components/cobs
             components/codec
@@ -109,6 +110,7 @@ jobs:
             components/qwiicnes
             components/remote_debug
             components/rmt
+            components/rtps
             components/rtsp
             components/runqueue
             components/rx8130ce

components/cdr/CMakeLists.txt

@@ -0,0 +1,3 @@
+idf_component_register(
+  INCLUDE_DIRS "include"
+  SRC_DIRS "src")

components/cdr/README.md

@@ -0,0 +1,34 @@
+# CDR (Common Data Representation) Component
+
+[![Badge](https://components.espressif.com/components/espp/cdr/badge.svg)](https://components.espressif.com/components/espp/cdr)
+
+The `cdr` component provides a small, standalone Common Data Representation
+(CDR) reader/writer utility aimed at standards-oriented protocols such as
+DDS/RTPS.
+
+This initial slice is intentionally focused on the most immediately useful
+pieces for building interoperable payloads:
+
+- encapsulation identifiers for `CDR_BE`, `CDR_LE`, `PL_CDR_BE`, and `PL_CDR_LE`
+- endian-aware primitive read/write helpers
+- CDR alignment and padding handling
+- string serialization helpers using the standard CDR length-prefix + null terminator format
+- headerless/body helpers for CDR fields embedded inside larger protocol elements
+- fixed-array helpers and zero-copy payload/span views
+- sequence helpers for homogeneous primitive collections
+- standalone usage without depending on RTPS or DDS layers
+
+Current scope:
+
+- good fit for building RTPS payloads and parameter lists incrementally
+- designed to stay reusable outside DDS/RTPS
+- **not** yet a full DDS XTypes / XCDR2 implementation
+
+## Example
+
+The [example](./example) demonstrates a small round-trip using:
+
+- a little-endian CDR encapsulation header
+- primitive values
+- a CDR string
+- a `uint16_t` sequence

components/cdr/example/CMakeLists.txt

@@ -0,0 +1,21 @@
+# The following lines of boilerplate have to be in your project's CMakeLists
+# in this exact order for cmake to work correctly
+cmake_minimum_required(VERSION 3.20)
+
+set(ENV{IDF_COMPONENT_MANAGER} "0")
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+set(EXTRA_COMPONENT_DIRS
+  "../../../components/"
+)
+
+set(
+  COMPONENTS
+  "main esptool_py cdr logger"
+  CACHE STRING
+  "List of components to include"
+  )
+
+project(cdr_example)
+
+set(CMAKE_CXX_STANDARD 20)

components/cdr/example/README.md

@@ -0,0 +1,30 @@
+# CDR Example
+
+This example demonstrates a small CDR round-trip using the `cdr` component.
+
+It exercises:
+
+- a little-endian CDR encapsulation header
+- primitive value serialization
+- CDR string serialization
+- `uint16_t` sequence serialization
+- fixed-array serialization with `write_array` / `read_array`
+- headerless/body CDR helpers for embedding fields inside a larger protocol value
+- round-trip parsing with `CdrReader`
+
+## How to use example
+
+### Build and Flash
+
+Build the project and flash it to the board, then run monitor tool to view serial output:
+
+```bash
+idf.py -p PORT flash monitor
+```
+
+Replace `PORT` with the name of the serial port to use.
+
+## Expected Output
+
+The example logs the encoded byte count and the decoded values. It finishes by
+printing `CDR round-trip succeeded`.

components/cdr/example/main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRC_DIRS "."
+                       INCLUDE_DIRS ".")

components/cdr/example/main/cdr_example.cpp

@@ -0,0 +1,68 @@
+#include <algorithm>
+#include <array>
+#include <string>
+#include <vector>
+
+#include "cdr.hpp"
+#include "logger.hpp"
+
+extern "C" void app_main(void) {
+  espp::Logger logger({.tag = "cdr_example", .level = espp::Logger::Verbosity::INFO});
+
+  std::array<uint8_t, 4> input_magic{'C', 'D', 'R', '!'};
+  std::array<uint16_t, 3> input_values{10, 20, 30};
+
+  //! [cdr example]
+  espp::CdrWriter writer({
+      .encapsulation = espp::CdrEncapsulation::CDR_LE,
+      .include_encapsulation = true,
+  });
+  writer.write<uint32_t>(42);
+  writer.write<float>(3.25f);
+  writer.write_string("hello cdr");
+  writer.write_sequence<uint16_t>(input_values);
+
+  auto payload = writer.take_buffer();
+  logger.info("Serialized {} bytes of CDR data", payload.size());
+
+  auto inline_writer = espp::CdrWriter::make_body_writer(espp::CdrEncapsulation::CDR_LE);
+  inline_writer.write_array(input_magic);
+  inline_writer.write_string("embedded field");
+  auto inline_payload =
+      espp::CdrWriter::encapsulate(inline_writer.payload(), espp::CdrEncapsulation::PL_CDR_LE);
+
+  espp::CdrReader reader(payload);
+  espp::CdrReader inline_reader(inline_payload);
+  uint32_t decoded_count = 0;
+  float decoded_scale = 0.0f;
+  std::string decoded_text;
+  std::vector<uint16_t> decoded_values;
+  std::array<uint8_t, 4> decoded_magic{};
+  std::string decoded_inline_text;
+
+  bool ok = reader.read<uint32_t>(decoded_count) && reader.read<float>(decoded_scale) &&
+            reader.read_string(decoded_text) && reader.read_sequence<uint16_t>(decoded_values);
+  bool inline_ok = inline_reader.encapsulation() == espp::CdrEncapsulation::PL_CDR_LE &&
+                   inline_reader.read_array(decoded_magic) &&
+                   inline_reader.read_string(decoded_inline_text);
+  //! [cdr example]
+
+  if (!ok || !inline_ok) {
+    logger.error("Failed to decode CDR payload");
+    return;
+  }
+
+  logger.info("Decoded count={}, scale={:.2f}, text='{}', sequence size={}, embedded='{}'",
+              decoded_count, decoded_scale, decoded_text, decoded_values.size(),
+              decoded_inline_text);
+
+  if (decoded_count != 42 || decoded_scale != 3.25f || decoded_text != "hello cdr" ||
+      decoded_values.size() != input_values.size() ||
+      !std::equal(decoded_values.begin(), decoded_values.end(), input_values.begin()) ||
+      decoded_magic != input_magic || decoded_inline_text != "embedded field") {
+    logger.error("CDR round-trip mismatch");
+    return;
+  }
+
+  logger.info("CDR round-trip succeeded");
+}

components/cdr/example/sdkconfig.defaults

@@ -0,0 +1 @@
+# Intentionally minimal; this example only exercises the CDR helpers.

components/cdr/idf_component.yml

@@ -0,0 +1,21 @@
+## IDF Component Manager Manifest File
+license: "MIT"
+description: "Common Data Representation (CDR) read/write helpers for ESP-IDF and cross-platform use."
+url: "https://github.com/esp-cpp/espp/tree/main/components/cdr"
+repository: "git://github.com/esp-cpp/espp.git"
+maintainers:
+  - William Emfinger <waemfinger@gmail.com>
+documentation: "https://esp-cpp.github.io/espp/cdr.html"
+examples:
+  - path: example
+tags:
+  - cpp
+  - Component
+  - CDR
+  - DDS
+  - RTPS
+  - Serialization
+  - XCDR
+dependencies:
+  idf:
+    version: '>=5.0'