intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 77 insertions, 0 deletions

diff --git a/library/cpp/yson_pull/detail/byte_writer.h b/library/cpp/yson_pull/detail/byte_writer.h
new file mode 100644
index 0000000000..dc1d4b4b96
--- /dev/null
+++ b/library/cpp/yson_pull/detail/byte_writer.h
@@ -0,0 +1,77 @@
+#pragma once
+
+#include "macros.h"
+
+#include <library/cpp/yson_pull/output.h>
+
+#include <util/system/types.h>
+
+#include <cstddef>
+#include <cstring>
+
+namespace NYsonPull {
+    namespace NDetail {
+        template <class StreamCounter>
+        class byte_writer {
+            NYsonPull::NOutput::IStream& stream_;
+            StreamCounter stream_counter_;
+
+        public:
+            byte_writer(NYsonPull::NOutput::IStream& stream)
+                : stream_(stream)
+            {
+            }
+
+            // const-ness added to prevent direct stream mutation
+            const NYsonPull::NOutput::IStream& stream() {
+                return stream_;
+            }
+            const StreamCounter& counter() {
+                return stream_counter_;
+            }
+
+            void flush_buffer() {
+                stream_.flush_buffer();
+            }
+
+            void advance(size_t bytes) {
+                auto& buf = stream_.buffer();
+                stream_counter_.update(
+                    buf.pos(),
+                    buf.pos() + bytes);
+                buf.advance(bytes);
+            }
+
+            void write(ui8 c) {
+                auto& buf = stream_.buffer();
+                if (Y_LIKELY(!buf.is_full())) {
+                    *buf.pos() = c;
+                    advance(1);
+                } else {
+                    auto ptr = reinterpret_cast<char*>(&c);
+                    stream_counter_.update(&c, &c + 1);
+                    stream_.flush_buffer({ptr, 1});
+                }
+            }
+
+            void write(const ui8* data, size_t size) {
+                auto& buf = stream_.buffer();
+                auto free_buf = buf.available();
+                if (Y_LIKELY(size < free_buf)) {
+                    ::memcpy(buf.pos(), data, size);
+                    advance(size);
+                } else {
+                    if (!buf.is_full()) {
+                        ::memcpy(buf.pos(), data, free_buf);
+                        advance(free_buf);
+                        data += free_buf;
+                        size -= free_buf;
+                    }
+                    stream_counter_.update(data, data + size);
+                    stream_.flush_buffer({reinterpret_cast<const char*>(data),
+                                          size});
+                }
+            }
+        };
+    }
+}