diff options
Diffstat (limited to 'src/nvim/memfile_defs.h')
| -rw-r--r-- | src/nvim/memfile_defs.h | 191 |
1 files changed, 100 insertions, 91 deletions
diff --git a/src/nvim/memfile_defs.h b/src/nvim/memfile_defs.h index 2e6e914b57..cc71e1a7ff 100644 --- a/src/nvim/memfile_defs.h +++ b/src/nvim/memfile_defs.h @@ -1,99 +1,108 @@ #ifndef NVIM_MEMFILE_DEFS_H #define NVIM_MEMFILE_DEFS_H -#include "nvim/types.h" - -typedef struct block_hdr bhdr_T; -typedef long blocknr_T; +#include <stdint.h> +#include <stdbool.h> -/* - * 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; +#include "nvim/types.h" -struct mf_hashitem_S { - mf_hashitem_T *mhi_next; - mf_hashitem_T *mhi_prev; +/// 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 hash item. +/// +/// Items' keys are block numbers. +/// Items in the same bucket are organized into a doubly-linked list. +/// +/// Therefore, items can be arbitrary data structures beginning with pointers +/// for the list and and a block number key. +typedef struct mf_hashitem { + struct mf_hashitem *mhi_next; + struct mf_hashitem *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_hashitem_T; + +/// Initial size for a hashtable. +#define MHT_INIT_SIZE 64 + +/// A chained hashtable with block numbers as keys and arbitrary data 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_hashtab { + size_t mht_mask; /// mask used to mod hash value to array index + /// (nr of items in array is 'mht_mask + 1') + size_t mht_count; /// number of items inserted + mf_hashitem_T **mht_buckets; /// points to the array of buckets (can be + /// mht_small_buckets or a newly allocated array + /// when mht_small_buckets becomes too small) + mf_hashitem_T *mht_small_buckets[MHT_INIT_SIZE]; /// initial buckets } 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 */ -}; - -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 */ -}; - -#endif // NVIM_MEMFILE_DEFS_H +/// 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 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. +typedef struct bhdr { + mf_hashitem_T bh_hashitem; /// header for hash table and key +#define bh_bnum bh_hashitem.mhi_key /// block number, part of bh_hashitem + + struct bhdr *bh_next; /// next block header in free or used list + struct bhdr *bh_prev; /// previous block header in used list + 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; + +/// A block number translation list item. +/// +/// 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 mf_blocknr_trans_item { + 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 +} mf_blocknr_trans_item_T; + +/// A memory file. +typedef 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 header in free list + bhdr_T *mf_used_first; /// mru block header in used list + bhdr_T *mf_used_last; /// lru block header 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 + bool mf_dirty; /// TRUE if there are dirty blocks +} memfile_T; + +#endif // NVIM_MEMFILE_DEFS_H |