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#pragma once
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include "nvim/map_defs.h"
/// A block number.
///
/// Blocks numbered from 0 upwards have been assigned a place in the actual
/// file. The block number is equal to the page number in the file. The blocks
/// with negative numbers are currently in memory only.
typedef int64_t blocknr_T;
/// A block header.
///
/// There is a block header for each previously used block in the memfile.
///
/// The block may be linked in the used list OR in the free list.
///
/// The used list is a doubly linked list, most recently used block first.
/// The blocks in the used list have a block of memory allocated.
/// The free list is a single linked list, not sorted.
/// The blocks in the free list have no block of memory allocated and
/// the contents of the block in the file (if any) is irrelevant.
typedef struct {
blocknr_T bh_bnum; ///< key used in hash table
void *bh_data; ///< pointer to memory (for used block)
unsigned bh_page_count; ///< number of pages in this block
#define BH_DIRTY 1U
#define BH_LOCKED 2U
unsigned bh_flags; ///< BH_DIRTY or BH_LOCKED
} bhdr_T;
typedef enum {
MF_DIRTY_NO = 0, ///< no dirty blocks
MF_DIRTY_YES, ///< there are dirty blocks
MF_DIRTY_YES_NOSYNC, ///< there are dirty blocks, do not sync yet
} mfdirty_T;
/// A memory file.
typedef struct {
char *mf_fname; ///< name of the file
char *mf_ffname; ///< idem, full path
int mf_fd; ///< file descriptor
bhdr_T *mf_free_first; ///< first block header in free list
/// The used blocks are kept in mf_hash.
/// mf_hash are used to quickly find a block in the used list.
PMap(int64_t) mf_hash;
/// When a block with a negative number is flushed to the file, it gets
/// a positive number. Because the reference to the block is still the negative
/// number, we remember the translation to the new positive number.
Map(int64_t, int64_t) mf_trans;
blocknr_T mf_blocknr_max; ///< highest positive block number + 1
blocknr_T mf_blocknr_min; ///< lowest negative block number - 1
blocknr_T mf_neg_count; ///< number of negative blocks numbers
blocknr_T mf_infile_count; ///< number of pages in the file
unsigned mf_page_size; ///< number of bytes in a page
mfdirty_T mf_dirty;
} memfile_T;
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