From 16d5d29049c08e21f57f7928ceedf40586a2d294 Mon Sep 17 00:00:00 2001
From: jacqueline <me@jacqueline.id.au>
Date: Sat, 3 Dec 2022 11:10:06 +1100
Subject: Use std::span (backported) and std::byte to make our buffers safer

---
 src/audio/stream_message.cpp | 45 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 41 insertions(+), 4 deletions(-)

(limited to 'src/audio/stream_message.cpp')

diff --git a/src/audio/stream_message.cpp b/src/audio/stream_message.cpp
index 58868ce8..055e7e96 100644
--- a/src/audio/stream_message.cpp
+++ b/src/audio/stream_message.cpp
@@ -3,24 +3,61 @@
 #include <cstdint>
 
 #include "cbor.h"
+#include "esp-idf/components/cbor/tinycbor/src/cbor.h"
+#include "span.hpp"
 
 namespace audio {
 
 const int kEncoderFlags = 0;
 const int kDecoderFlags = 0;
 
-auto ReadMessageType(uint8_t* buffer, size_t length) -> MessageType {
+auto WriteTypeOnlyMessage(MessageType type, cpp::span<std::byte> data)
+    -> cpp::result<size_t, CborError> {
+  CborEncoder root;
+  CborEncoder container;
+  uint8_t* cast_data = reinterpret_cast<uint8_t*>(data.data());
+
+  cbor_encoder_init(&root, cast_data, data.size(), kEncoderFlags);
+  cbor_encode_uint(&container, type);
+
+  return cbor_encoder_get_buffer_size(&root, cast_data);
+}
+
+auto ReadMessageType(cpp::span<std::byte> msg) -> MessageType {
   CborParser parser;
   CborValue root;
   CborValue container;
 
-  cbor_parser_init(buffer, length, kDecoderFlags, &parser, &root);
-  cbor_value_enter_container(&root, &container);
+  cbor_parser_init(reinterpret_cast<uint8_t*>(msg.data()), msg.size(),
+                   kDecoderFlags, &parser, &root);
 
   uint64_t header = 0;
-  cbor_value_get_uint64(&container, &header);
+  if (cbor_value_is_container(&root)) {
+    cbor_value_enter_container(&root, &container);
+    cbor_value_get_uint64(&container, &header);
+  } else {
+    cbor_value_get_uint64(&root, &header);
+  }
 
   return static_cast<MessageType>(header);
 }
 
+auto GetAdditionalData(cpp::span<std::byte> msg) -> cpp::span<std::byte> {
+  CborParser parser;
+  CborValue root;
+  uint8_t* cast_data = reinterpret_cast<uint8_t*>(msg.data());
+
+  cbor_parser_init(cast_data, msg.size(), kDecoderFlags, &parser, &root);
+
+  while (!cbor_value_at_end(&root)) {
+    cbor_value_advance(&root);
+  }
+
+  const uint8_t* remaining = cbor_value_get_next_byte(&root);
+  size_t header_size = remaining - cast_data;
+
+  return cpp::span<std::byte>(msg.data() + header_size,
+                              msg.size() - header_size);
+}
+
 }  // namespace audio
-- 
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