YQL-16239 Move purecalc to public

1 files changed, 159 insertions, 0 deletions

diff --git a/library/cpp/microbdb/header.h b/library/cpp/microbdb/header.h
new file mode 100644
index 0000000000..0951d610ea
--- /dev/null
+++ b/library/cpp/microbdb/header.h
@@ -0,0 +1,159 @@
+#pragma once
+
+#include <util/system/defaults.h>
+#include <util/generic/typetraits.h>
+#include <util/generic/string.h>
+#include <util/str_stl.h>
+
+#include <stdio.h>
+
+#define METASIZE (1u << 12)
+#define METASIG 0x12345678u
+#define PAGESIG 0x87654321u
+
+enum EMbdbErrors {
+    MBDB_ALREADY_INITIALIZED = 200,
+    MBDB_NOT_INITIALIZED = 201,
+    MBDB_BAD_DESCRIPTOR = 202,
+    MBDB_OPEN_ERROR = 203,
+    MBDB_READ_ERROR = 204,
+    MBDB_WRITE_ERROR = 205,
+    MBDB_CLOSE_ERROR = 206,
+    MBDB_EXPECTED_EOF = 207,
+    MBDB_UNEXPECTED_EOF = 208,
+    MBDB_BAD_FILENAME = 209,
+    MBDB_BAD_METAPAGE = 210,
+    MBDB_BAD_RECORDSIG = 211,
+    MBDB_BAD_FILE_SIZE = 212,
+    MBDB_BAD_PAGESIG = 213,
+    MBDB_BAD_PAGESIZE = 214,
+    MBDB_BAD_PARM = 215,
+    MBDB_BAD_SYNC = 216,
+    MBDB_PAGE_OVERFLOW = 217,
+    MBDB_NO_MEMORY = 218,
+    MBDB_MEMORY_LEAK = 219,
+    MBDB_NOT_SUPPORTED = 220
+};
+
+TString ToString(EMbdbErrors error);
+TString ErrorMessage(int error, const TString& text, const TString& path = TString(), ui32 recordSig = 0, ui32 gotRecordSig = 0);
+
+enum EPageFormat {
+    MBDB_FORMAT_RAW = 0,
+    MBDB_FORMAT_COMPRESSED = 1,
+    MBDB_FORMAT_NULL = 255
+};
+
+enum ECompressionAlgorithm {
+    MBDB_COMPRESSION_ZLIB = 1,
+    MBDB_COMPRESSION_FASTLZ = 2,
+    MBDB_COMPRESSION_SNAPPY = 3
+};
+
+struct TDatMetaPage {
+    ui32 MetaSig;
+    ui32 RecordSig;
+    ui32 PageSize;
+};
+
+struct TDatPage {
+    ui32 RecNum; //!< number of records on this page
+    ui32 PageSig;
+    ui32 Format : 2; //!< one of EPageFormat
+    ui32 Reserved : 30;
+};
+
+/// Additional page header with compression info
+struct TCompressedPage {
+    ui32 BlockCount;
+    ui32 Algorithm : 4;
+    ui32 Version : 4;
+    ui32 Reserved : 24;
+};
+
+namespace NMicroBDB {
+    /// Header of compressed block
+    struct TCompressedHeader {
+        ui32 Compressed;
+        ui32 Original; /// original size of block
+        ui32 Count;    /// number of records in block
+        ui32 Reserved;
+    };
+
+    Y_HAS_MEMBER(AssertValid);
+
+    template <typename T, bool TVal>
+    struct TAssertValid {
+        void operator()(const T*) {
+        }
+    };
+
+    template <typename T>
+    struct TAssertValid<T, true> {
+        void operator()(const T* rec) {
+            return rec->AssertValid();
+        }
+    };
+
+    template <typename T>
+    void AssertValid(const T* rec) {
+        return NMicroBDB::TAssertValid<T, NMicroBDB::THasAssertValid<T>::value>()(rec);
+    }
+
+    Y_HAS_MEMBER(SizeOf);
+
+    template <typename T, bool TVal>
+    struct TGetSizeOf;
+
+    template <typename T>
+    struct TGetSizeOf<T, true> {
+        size_t operator()(const T* rec) {
+            return rec->SizeOf();
+        }
+    };
+
+    template <typename T>
+    struct TGetSizeOf<T, false> {
+        size_t operator()(const T*) {
+            return sizeof(T);
+        }
+    };
+
+    inline char* GetFirstRecord(const TDatPage* page) {
+        switch (page->Format) {
+            case MBDB_FORMAT_RAW:
+                return (char*)page + sizeof(TDatPage);
+            case MBDB_FORMAT_COMPRESSED:
+                // Первая запись на сжатой странице сохраняется несжатой
+                // сразу же после всех заголовков.
+                // Алгоритм сохранения смотреть в TOutputRecordIterator::FlushBuffer
+                return (char*)page + sizeof(TDatPage) + sizeof(TCompressedPage) + sizeof(NMicroBDB::TCompressedHeader);
+        }
+        return (char*)nullptr;
+    }
+}
+
+template <typename T>
+size_t SizeOf(const T* rec) {
+    return NMicroBDB::TGetSizeOf<T, NMicroBDB::THasSizeOf<T>::value>()(rec);
+}
+
+template <typename T>
+size_t MaxSizeOf() {
+    return sizeof(T);
+}
+
+static inline int DatNameToIdx(char iname[/*FILENAME_MAX*/], const char* dname) {
+    if (!dname || !*dname)
+        return MBDB_BAD_FILENAME;
+    const char* ptr;
+    if (!(ptr = strrchr(dname, '/')))
+        ptr = dname;
+    if (!(ptr = strrchr(ptr, '.')))
+        ptr = strchr(dname, 0);
+    if (ptr - dname > FILENAME_MAX - 5)
+        return MBDB_BAD_FILENAME;
+    memcpy(iname, dname, ptr - dname);
+    strcpy(iname + (ptr - dname), ".idx");
+    return 0;
+}