%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2001-2016. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
-define(DEFAULT_MIN_NO_SLOTS, 256).
-define(DEFAULT_MAX_NO_SLOTS, 32*1024*1024).
-define(DEFAULT_AUTOSAVE, 3). % minutes
-define(DEFAULT_CACHE, {3000, 14000}). % cache_parms()
%% Type.
-define(SET, 1).
-define(BAG, 2).
-define(DUPLICATE_BAG, 3).
-define(MAGIC, 16#0abcdef). % dets cookie, won't ever change.
%% Status values.
-define(FREE, 16#3abcdef).
-define(ACTIVE, 16#12345678).
-define(FILE_FORMAT_VERSION_POS, 16).
-define(CHUNK_SIZE, 8192).
-define(SERVER_NAME, dets).
-define(POW(X), (1 bsl (X))).
%% REM2(A,B) = A rem B, if B is a power of 2.
-define(REM2(A, B), ((A) band ((B)-1))).
-define(DETS_CALL(Pid, Req), {'$dets_call', Pid, Req}).
-type access() :: 'read' | 'read_write'.
-type auto_save() :: 'infinity' | non_neg_integer().
-type hash_bif() :: 'phash' | 'phash2'.
-type keypos() :: pos_integer().
-type no_colls() :: [{LogSize :: non_neg_integer(),
NoCollections :: non_neg_integer()}].
-type no_slots() :: 'default' | non_neg_integer().
-type tab_name() :: term().
-type type() :: 'bag' | 'duplicate_bag' | 'set'.
-type update_mode() :: 'dirty'
| 'new_dirty'
| 'saved'
| {'error', Reason :: term()}.
%% Record holding the file header and more.
-record(head, {
m :: non_neg_integer(), % size
m2 :: non_neg_integer(), % m * 2
next :: non_neg_integer(), % next position for growth
% (segm mgmt only)
fptr :: file:fd(), % the file descriptor
no_objects :: non_neg_integer() , % number of objects in table,
no_keys :: non_neg_integer(), % number of keys
maxobjsize :: 'undefined' | non_neg_integer(), % 2-log of
% the size of the biggest object collection
n, % split indicator
type :: type(),
keypos :: keypos(), % default is 1 as for ets
freelists :: 'undefined'
| tuple(), % tuple of free lists of buddies
% if fixed =/= false, then a pair of freelists
freelists_p :: 'undefined'
| non_neg_integer(), % cached FreelistsPointer
no_collections :: 'undefined'
| no_colls(), % number of object collections
% per size (version 9(b))
auto_save :: auto_save(),
update_mode :: update_mode(),
fixed = false :: 'false'
| {{integer(), integer()}, % time of first fix,
[{pid(), % and number of fixes per process
non_neg_integer()}]},
hash_bif :: hash_bif(), % hash bif used for this file
has_md5 :: boolean(), % whether the header has
% an MD5 sum (version 9(c))
min_no_slots :: no_slots(), % minimum number of slots
max_no_slots :: no_slots(), % maximum number of slots
cache :: 'undefined' | cache(), % Write cache.
filename :: file:name(), % name of the file being used
access = read_write :: access(),
ram_file = false :: boolean(),
name :: tab_name(), % the name of the table
parent :: 'undefined' | pid(), % The supervisor of Dets processes.
server :: 'undefined' | pid(), % The creator of Dets processes.
bump :: non_neg_integer(),
base :: non_neg_integer()
}).
%% Info extracted from the file header.
-record(fileheader, {
freelist :: non_neg_integer(),
fl_base :: non_neg_integer(),
cookie :: non_neg_integer(),
closed_properly :: non_neg_integer(),
type :: 'badtype' | type(),
version :: non_neg_integer(),
m :: non_neg_integer(),
next :: non_neg_integer(),
keypos :: keypos(),
no_objects :: non_neg_integer(),
no_keys :: non_neg_integer(),
min_no_slots :: non_neg_integer(),
max_no_slots :: non_neg_integer(),
no_colls :: 'undefined' | no_colls(),
hash_method :: non_neg_integer(),
read_md5 :: binary(),
has_md5 :: boolean(),
md5 :: binary(),
trailer :: non_neg_integer(),
eof :: non_neg_integer(),
n
}).
-type delay() :: non_neg_integer().
-type threshold() :: non_neg_integer().
-type cache_parms() ::
{Delay :: delay(), % max time items are kept in RAM only,
% in milliseconds
Size :: threshold()}. % threshold size of cache, in bytes
%% Write Cache.
-record(cache, {
cache :: % write cache, last item first
[{Key :: term(),
{Seq :: non_neg_integer(), Item :: term()}}],
csize :: non_neg_integer(), % current size of the cached items
inserts :: % upper limit on number of inserted keys
non_neg_integer(),
wrtime :: 'undefined' | integer(), % last write or update time
tsize :: threshold(), % threshold size of cache
delay :: delay() % max time items are kept in RAM only
}).
-type cache() :: #cache{}.
