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module Netmcore_hashtbl

: sig

Shared hashtables

This is a shared memory version of Hashtbl. Note that the degree of parallelization is quite restricted - practically all operations need to be serialized (with the exception of the "ro" variants).

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type ('a, 'b, 'h) t

The type of hash tables from type 'a to type 'b and a header of type 'h

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type ('a, 'b, 'h) t_descr

The marshallable descriptor of a shared hash table

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val create : Netmcore.res_id -> 'h -> ('a, 'b, 'h) t

Hashtbl.create pool h creates a new, empty hash table in pool with a header h.

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val clear : ('a, 'b, 'h) t -> unit

Empty a hash table.

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val add : ('a, 'b, 'h) t -> 'a -> 'b -> unit

add tbl x y adds a binding of x to y in table tbl. Previous bindings for x are not removed, but simply hidden. That is, after performing Netmcore_hashtbl.removetbl x, the previous binding for x, if any, is restored. (Same behavior as with association lists.)

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val find_ro : ('a, 'b, 'h) t -> 'a -> 'b

find_ro tbl x returns the current binding of x in tbl, or raises Not_found if no such binding exists. If it is possible that the table is being modified at the same time, this function can crash. (Suffix "_ro" = for "read-only" hashtables.)

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val find_p : ('a, 'b, 'h) t -> 'a -> ('b -> 'r) -> 'r

find_p tbl x f looks up the current binding of x in tbl, and calls f with this binding as argument. During the execution of f the binding is pinned and cannot be garbage-collected. Raises Not_found if there is no such binding.

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val find_c : ('a, 'b, 'h) t -> 'a -> 'b

Like find but returns a copy of the binding in normal RAM

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val find_all_ro : ('a, 'b, 'h) t -> 'a -> 'b list

Hashtbl.find_all tbl x returns the list of all data associated with x in tbl. The current binding is returned first, then the previous bindings, in reverse order of introduction in the table. If it is possible that the table is being modified at the same time, this function can crash. (Suffix "_ro" = for "read-only" hashtables.)

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val find_all_p : ('a, 'b, 'h) t -> 'a -> ('b list -> 'r) -> 'r

Version of find_all with pinned result

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val find_all_c : ('a, 'b, 'h) t -> 'a -> 'b list

Version of find_all with copied result

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val mem_ro : ('a, 'b, 'h) t -> 'a -> bool

Hashtbl.mem tbl x checks if x is bound in tbl. If it is possible that the table is being modified at the same time, this function can crash. (Suffix "_ro" = for "read-only" hashtables.)

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val mem : ('a, 'b, 'h) t -> 'a -> bool

Safe version of mem_ro in the presence of parallel modifications. It is a bit slower, though.

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val remove : ('a, 'b, 'h) t -> 'a -> unit

Hashtbl.remove tbl x removes the current binding of x in tbl, restoring the previous binding if it exists. It does nothing if x is not bound in tbl.

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val replace : ('a, 'b, 'h) t -> 'a -> 'b -> unit

Hashtbl.replace tbl x y replaces the current binding of x in tbl by a binding of x to y. If x is unbound in tbl, a binding of x to y is added to tbl. This is functionally equivalent to Hashtbl.removetbl x followed by Hashtbl.addtbl x y.

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val iter : ('a -> 'b -> unit) -> ('a, 'b, 'h) t -> unit

Hashtbl.iter f tbl applies f to all bindings in table tbl. f receives the key as first argument, and the associated value as second argument. Each binding is presented exactly once to f. The order in which the bindings are passed to f is unspecified. However, if the table contains several bindings for the same key, they are passed to f in reverse order of introduction, that is, the most recent binding is passed first.

The table cannot be modified while iter is running. Any attempt will result in a deadlock.

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val length : ('a, 'b, 'h) t -> int

Hashtbl.length tbl returns the number of bindings in tbl. Multiple bindings are counted multiply, so Hashtbl.length gives the number of times Hashtbl.iter calls its first argument.

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val header : ('a, 'b, 'h) t -> 'h

Returns the header

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val heap : ('a, 'b, 'h) t -> Obj.t Netmcore_heap.heap

Returns the heap backing this data structure

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val descr_of_hashtbl : ('a, 'b, 'h) t -> ('a, 'b, 'h) t_descr

Returns the descriptor

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val hashtbl_of_descr : Netmcore.res_id -> ('a, 'b, 'h) t_descr -> ('a, 'b, 'h) t

Look up the hash table for this descriptor

end