[Yunq] Move serialization to yunq library.

lib/yunq/serialize.h

@@ -1,11 +1,84 @@
 #pragma once
 
 #include <glacier/buffer/byte_buffer.h>
+#include <glacier/buffer/cap_buffer.h>
+#include <glacier/container/optional.h>
+#include <glacier/container/vector.h>
+#include <glacier/memory/reference.h>
 #include <glacier/status/status.h>
 
+#include "yunq/yunq.h"
+
 namespace yunq {
 
-void WriteHeader(glcr::ByteBuffer& bytes, uint64_t offset, uint32_t core_size,
-                 uint32_t extension_size);
+class Serializer {
+ public:
+  Serializer(glcr::ByteBuffer& bytes, uint64_t offset, uint64_t num_fields)
+      : buffer_(bytes),
+        offset_(offset),
+        next_extension_(kHeaderSize + (8 * num_fields)),
+        core_size_(next_extension_),
+        caps_() {}
+  Serializer(glcr::ByteBuffer& bytes, uint64_t offset, uint64_t num_fields,
+             glcr::CapBuffer& caps)
+      : buffer_(bytes),
+        offset_(offset),
+        next_extension_(kHeaderSize + (8 * num_fields)),
+        core_size_(next_extension_),
+        caps_(caps) {}
+
+  template <typename T>
+  void WriteField(uint64_t field_index, const T& value);
+
+  template <typename T>
+  void WriteRepeated(uint64_t field_index, const glcr::Vector<T>& value);
+
+  void WriteCapability(uint64_t field_index, uint64_t value);
+
+  void WriteRepeatedCapability(uint64_t field_index,
+                               const glcr::Vector<uint64_t>& value);
+
+  void WriteHeader();
+
+  uint64_t size() const { return next_extension_; }
+
+ private:
+  glcr::ByteBuffer& buffer_;
+  uint64_t offset_;
+  uint64_t next_extension_;
+  uint64_t core_size_;
+  uint64_t next_cap_ = 0;
+  glcr::Optional<glcr::Ref<glcr::CapBuffer>> caps_;
+
+  uint64_t field_offset(uint64_t field_index) const {
+    return offset_ + kHeaderSize + (8 * field_index);
+  }
+};
+
+template <typename T>
+void Serializer::WriteField(uint64_t field_index, const T& value) {
+  buffer_.WriteAt<T>(field_offset(field_index), value);
+}
+
+template <>
+void Serializer::WriteField<glcr::String>(uint64_t field_index,
+                                          const glcr::String& value);
+
+template <typename T>
+void Serializer::WriteRepeated(uint64_t field_index,
+                               const glcr::Vector<T>& value) {
+  ExtensionPointer ptr{
+      .offset = (uint32_t)next_extension_,
+      .length = (uint32_t)(value.size() * sizeof(T)),
+  };
+
+  next_extension_ += ptr.length;
+  buffer_.WriteAt<ExtensionPointer>(field_offset(field_index), ptr);
+
+  for (uint64_t i = 0; i < value.size(); i++) {
+    uint32_t ext_offset = offset_ + ptr.offset + (i * sizeof(T));
+    buffer_.WriteAt<T>(ext_offset, value.at(i));
+  }
+}
 
 }  // namespace yunq