Add cbor wrapper, and chunk streaming util

1 files changed, 90 insertions, 0 deletions

diff --git a/src/audio/stream_info.cpp b/src/audio/stream_info.cpp
new file mode 100644
index 00000000..bb9b1fa2
--- /dev/null
+++ b/src/audio/stream_info.cpp
@@ -0,0 +1,90 @@
+#include "stream_info.hpp"
+#include "stream_message.hpp"
+#include <cstdint>
+#include "esp-idf/components/cbor/tinycbor/src/cbor.h"
+
+namespace audio {
+
+  static const char* kKeyPath = "p";
+  static const char* kKeyChannels = "c";
+  static const char* kKeyBitsPerSample = "b";
+  static const char* kKeySampleRate = "r";
+
+  static auto find_uint64(CborValue &map, char *key) -> cpp::optional<uint64_t> {
+    CborValue val;
+    cbor_value_map_find_value(&map, key, &val);
+    if (cbor_value_is_unsigned_integer(&val)) {
+      uint64_t raw_val;
+      cbor_value_get_uint64(&val, &raw_val);
+      return raw_val;
+    }
+    return {};
+  }
+
+
+  static auto write_uint64(CborEncoder &map, const char *key, const optional<uint64_t> &val) -> cpp::result<void, StreamInfo::EncodeError> {
+    if (val) {
+      cbor_encode_byte_string(&map, key, 1);
+      cbor_encode_uint(&map, *val);
+    }
+    return {};
+  }
+
+static auto StreamInfo::Create(const uint8_t *buffer, size_t length) -> cpp::result<StreamInfo, ParseError> {
+  CborParser parser;
+  CborValue value;
+
+  cbor_parser_init(buffer, len, 0, &parser, &value);
+
+  uint8_t type = 0;
+  if (!cbor_value_is_integer(&value)
+      || !cbor_value_get_integer(&value, &type)
+      || type != STREAM_INFO) {
+    return cpp::fail(WRONG_TYPE);
+  }
+
+  cbor_value_advance_fixed(&value);
+
+  if (!cbor_value_is_map(&value)) {
+    return cpp::fail(MISSING_MAP);
+  }
+
+  return StreamInfo(value);
+}
+
+StreamInfo::StreamInfo(CborValue& map) {
+  // TODO: this method is n^2, which seems less than ideal. But you don't do it
+  // that frequently, so maybe it's okay? Needs investigation.
+  channels_ = find_uint64(map, kKeyChannels);
+  bits_per_sample_ = find_uint64(map, kKeyBitsPerSample);
+  sample_rate_ = find_uint64(map, kKeySampleRate);
+
+  CborValue val;
+  cbor_value_map_find_value(&map, kKeyPath, &val);
+  if (cbor_value_is_text_string(&val)) {
+    size_t len;
+    char *str;
+    cbor_value_dup_text_string(&val, &str, &len, &val);
+    path_ = std::string(str, len);
+    free(str);
+  }
+}
+
+auto StreamInfo::WriteToStream(CborEncoder encoder) -> cpp::result<void, EncodeError> {
+  cbor_encode_int(&encoder, STREAM_INFO);
+
+  CborEncoder map;
+  cbor_encoder_create_map(&encoder, &map, length);
+
+  write_uint64(&map, kKeyChannels, channels_);
+  write_uint64(&map, kKeyBitsPerSample, bits_per_sample_);
+  write_uint64(&map, kKeySampleRate, sample_rate_);
+
+  if (path_) {
+    cbor_encode_text_string(&map, path_->c_str(), path_->size());
+  }
+
+  cbor_encoder_close_container(&encoder, &map);
+}
+
+} // namespace audio