diff options
Diffstat (limited to 'src/nvim/memfile_defs.h')
| -rw-r--r-- | src/nvim/memfile_defs.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/src/nvim/memfile_defs.h b/src/nvim/memfile_defs.h new file mode 100644 index 0000000000..e614cae7ca --- /dev/null +++ b/src/nvim/memfile_defs.h @@ -0,0 +1,107 @@ +#ifndef NEOVIM_MEMFILE_DEFS_H +#define NEOVIM_MEMFILE_DEFS_H + +typedef struct block_hdr bhdr_T; +typedef long blocknr_T; + +/* + * mf_hashtab_T is a chained hashtable with blocknr_T key and arbitrary + * structures as items. This is an intrusive data structure: we require + * that items begin with mf_hashitem_T which contains the key and linked + * list pointers. List of items in each bucket is doubly-linked. + */ + +typedef struct mf_hashitem_S mf_hashitem_T; + +struct mf_hashitem_S { + mf_hashitem_T *mhi_next; + mf_hashitem_T *mhi_prev; + blocknr_T mhi_key; +}; + +#define MHT_INIT_SIZE 64 + +typedef struct mf_hashtab_S { + long_u mht_mask; /* mask used for hash value (nr of items + * in array is "mht_mask" + 1) */ + long_u mht_count; /* nr of items inserted into hashtable */ + mf_hashitem_T **mht_buckets; /* points to mht_small_buckets or + *dynamically allocated array */ + mf_hashitem_T *mht_small_buckets[MHT_INIT_SIZE]; /* initial buckets */ + char mht_fixed; /* non-zero value forbids growth */ +} mf_hashtab_T; + +/* + * for each (previously) used block in the memfile there is one block header. + * + * The block may be linked in the used list OR in the free list. + * The used blocks are also kept in hash lists. + * + * 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. + * mf_used_count is the number of pages in the used list. + * The hash lists are used to quickly find a block in the used list. + * 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. + */ + +struct block_hdr { + mf_hashitem_T bh_hashitem; /* header for hash table and key */ +#define bh_bnum bh_hashitem.mhi_key /* block number, part of bh_hashitem */ + + bhdr_T *bh_next; /* next block_hdr in free or used list */ + bhdr_T *bh_prev; /* previous block_hdr in used list */ + char_u *bh_data; /* pointer to memory (for used block) */ + int bh_page_count; /* number of pages in this block */ + +#define BH_DIRTY 1 +#define BH_LOCKED 2 + char bh_flags; /* BH_DIRTY or BH_LOCKED */ +}; + +/* + * 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 in the + * double linked trans lists. The structure is the same as the hash lists. + */ +typedef struct nr_trans NR_TRANS; + +struct nr_trans { + mf_hashitem_T nt_hashitem; /* header for hash table and key */ +#define nt_old_bnum nt_hashitem.mhi_key /* old, negative, number */ + + blocknr_T nt_new_bnum; /* new, positive, number */ +}; + +#define MF_SEED_LEN 8 + +struct memfile { + char_u *mf_fname; /* name of the file */ + char_u *mf_ffname; /* idem, full path */ + int mf_fd; /* file descriptor */ + bhdr_T *mf_free_first; /* first block_hdr in free list */ + bhdr_T *mf_used_first; /* mru block_hdr in used list */ + bhdr_T *mf_used_last; /* lru block_hdr in used list */ + unsigned mf_used_count; /* number of pages in used list */ + unsigned mf_used_count_max; /* maximum number of pages in memory */ + mf_hashtab_T mf_hash; /* hash lists */ + mf_hashtab_T mf_trans; /* trans lists */ + 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 */ + int mf_dirty; /* TRUE if there are dirty blocks */ + buf_T *mf_buffer; /* bufer this memfile is for */ + char_u mf_seed[MF_SEED_LEN]; /* seed for encryption */ + + /* Values for key, method and seed used for reading data blocks when + * updating for a newly set key or method. Only when mf_old_key != NULL. */ + char_u *mf_old_key; + int mf_old_cm; + char_u mf_old_seed[MF_SEED_LEN]; +}; + +#endif // NEOVIM_MEMFILE_DEFS_H |