YT-19324: move YT provider to ydb/library/yql

This commit is formed by the following script: https://paste.yandex-team.ru/6f92e4b8-efc5-4d34-948b-15ee2accd7e7/text.
This commit has zero effect on all projects that depend on YQL.

The summary of changes:
- `yql/providers/yt -> ydb/library/yql/providers/yt `- the whole implementation of YT provider is moved into YDB code base for further export as a part of YT YQL plugin shared library;
- `yql/providers/stat/{expr_nodes,uploader} -> ydb/library/yql/providers/stat/{expr_nodes,uploader}` - a small interface without implementation and the description of stat expr nodes;
- `yql/core/extract_predicate/ut -> ydb/library/yql/core/extract_predicate/ut`;
- `yql/core/{ut,ut_common} -> ydb/library/yql/core/{ut,ut_common}`;
- `yql/core` is gone;
- `yql/library/url_preprocessing -> ydb/library/yql/core/url_preprocessing`.

**NB**: all new targets inside `ydb/` are under `IF (NOT CMAKE_EXPORT)` clause which disables them from open-source cmake generation and ya make build. They will be enabled in the subsequent commits.

1 files changed, 57 insertions, 0 deletions

diff --git a/library/cpp/erasure/public.h b/library/cpp/erasure/public.h
new file mode 100644
index 0000000000..d5cf01297b
--- /dev/null
+++ b/library/cpp/erasure/public.h
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <util/generic/buffer.h>
+#include <util/generic/yexception.h>
+#include <util/memory/blob.h>
+#include <util/string/cast.h>
+#include <util/system/src_root.h>
+
+#include <vector>
+
+#include <bitset>
+
+namespace NErasure {
+
+//! The maximum total number of blocks our erasure codec can handle.
+static constexpr int MaxTotalPartCount = 16;
+
+//! Max word size to use. `w` in jerasure notation
+static constexpr int MaxWordSize = 8;
+
+//! Max threshold to generate bitmask for CanRepair indices for LRC encoding.
+static constexpr int BitmaskOptimizationThreshold = 22;
+
+//! A vector type for holding block indexes.
+using TPartIndexList = std::vector<int>;
+
+//! Each bit corresponds to a possible block index.
+using TPartIndexSet = std::bitset<MaxTotalPartCount>;
+
+template <class TBlobType>
+struct ICodec;
+
+struct TDefaultCodecTraits {
+    using TBlobType = TBlob;
+    using TMutableBlobType = TBlob;
+    using TBufferType = TBuffer;
+
+    static inline TMutableBlobType AllocateBlob(size_t size) {
+        TBufferType buffer(size);
+        buffer.Resize(size);
+        // The buffer is cleared after this call so no use after free.
+        return TBlob::FromBuffer(buffer);
+    }
+
+    // AllocateBuffer must fill the memory with 0.
+    static inline TBufferType AllocateBuffer(size_t size) {
+        TBufferType buffer(size);
+        buffer.Fill(0, size);
+        return buffer;
+    }
+
+    static inline TBlobType FromBufferToBlob(TBufferType&& blob) {
+        return TBlobType::FromBuffer(blob);
+    }
+};
+
+} // namespace NErasure