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#       1                 :            : // Copyright (c) 2009-2010 Satoshi Nakamoto
#       2                 :            : // Copyright (c) 2009-2020 The Bitcoin Core developers
#       3                 :            : // Distributed under the MIT software license, see the accompanying
#       4                 :            : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
#       5                 :            : 
#       6                 :            : #ifndef BITCOIN_FLATFILE_H
#       7                 :            : #define BITCOIN_FLATFILE_H
#       8                 :            : 
#       9                 :            : #include <string>
#      10                 :            : 
#      11                 :            : #include <fs.h>
#      12                 :            : #include <serialize.h>
#      13                 :            : 
#      14                 :            : struct FlatFilePos
#      15                 :            : {
#      16                 :            :     int nFile;
#      17                 :            :     unsigned int nPos;
#      18                 :            : 
#      19                 :      15443 :     SERIALIZE_METHODS(FlatFilePos, obj) { READWRITE(VARINT_MODE(obj.nFile, VarIntMode::NONNEGATIVE_SIGNED), VARINT(obj.nPos)); }
#      20                 :            : 
#      21                 :     477843 :     FlatFilePos() : nFile(-1), nPos(0) {}
#      22                 :            : 
#      23                 :            :     FlatFilePos(int nFileIn, unsigned int nPosIn) :
#      24                 :            :         nFile(nFileIn),
#      25                 :            :         nPos(nPosIn)
#      26                 :       8279 :     {}
#      27                 :            : 
#      28                 :          0 :     friend bool operator==(const FlatFilePos &a, const FlatFilePos &b) {
#      29                 :          0 :         return (a.nFile == b.nFile && a.nPos == b.nPos);
#      30                 :          0 :     }
#      31                 :            : 
#      32                 :          0 :     friend bool operator!=(const FlatFilePos &a, const FlatFilePos &b) {
#      33                 :          0 :         return !(a == b);
#      34                 :          0 :     }
#      35                 :            : 
#      36                 :        428 :     void SetNull() { nFile = -1; nPos = 0; }
#      37                 :     435038 :     bool IsNull() const { return (nFile == -1); }
#      38                 :            : 
#      39                 :            :     std::string ToString() const;
#      40                 :            : };
#      41                 :            : 
#      42                 :            : /**
#      43                 :            :  * FlatFileSeq represents a sequence of numbered files storing raw data. This class facilitates
#      44                 :            :  * access to and efficient management of these files.
#      45                 :            :  */
#      46                 :            : class FlatFileSeq
#      47                 :            : {
#      48                 :            : private:
#      49                 :            :     const fs::path m_dir;
#      50                 :            :     const char* const m_prefix;
#      51                 :            :     const size_t m_chunk_size;
#      52                 :            : 
#      53                 :            : public:
#      54                 :            :     /**
#      55                 :            :      * Constructor
#      56                 :            :      *
#      57                 :            :      * @param dir The base directory that all files live in.
#      58                 :            :      * @param prefix A short prefix given to all file names.
#      59                 :            :      * @param chunk_size Disk space is pre-allocated in multiples of this amount.
#      60                 :            :      */
#      61                 :            :     FlatFileSeq(fs::path dir, const char* prefix, size_t chunk_size);
#      62                 :            : 
#      63                 :            :     /** Get the name of the file at the given position. */
#      64                 :            :     fs::path FileName(const FlatFilePos& pos) const;
#      65                 :            : 
#      66                 :            :     /** Open a handle to the file at the given position. */
#      67                 :            :     FILE* Open(const FlatFilePos& pos, bool read_only = false);
#      68                 :            : 
#      69                 :            :     /**
#      70                 :            :      * Allocate additional space in a file after the given starting position. The amount allocated
#      71                 :            :      * will be the minimum multiple of the sequence chunk size greater than add_size.
#      72                 :            :      *
#      73                 :            :      * @param[in] pos The starting position that bytes will be allocated after.
#      74                 :            :      * @param[in] add_size The minimum number of bytes to be allocated.
#      75                 :            :      * @param[out] out_of_space Whether the allocation failed due to insufficient disk space.
#      76                 :            :      * @return The number of bytes successfully allocated.
#      77                 :            :      */
#      78                 :            :     size_t Allocate(const FlatFilePos& pos, size_t add_size, bool& out_of_space);
#      79                 :            : 
#      80                 :            :     /**
#      81                 :            :      * Commit a file to disk, and optionally truncate off extra pre-allocated bytes if final.
#      82                 :            :      *
#      83                 :            :      * @param[in] pos The first unwritten position in the file to be flushed.
#      84                 :            :      * @param[in] finalize True if no more data will be written to this file.
#      85                 :            :      * @return true on success, false on failure.
#      86                 :            :      */
#      87                 :            :     bool Flush(const FlatFilePos& pos, bool finalize = false);
#      88                 :            : };
#      89                 :            : 
#      90                 :            : #endif // BITCOIN_FLATFILE_H