compare.ml
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(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
(* Copyright (c) 2021 Nomadic Labs <contact@nomadic-labs.com> *)
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module type COMPARABLE = sig
type t
val compare : t -> t -> int
end
module type S = sig
type t
val ( = ) : t -> t -> bool
val ( <> ) : t -> t -> bool
val ( < ) : t -> t -> bool
val ( <= ) : t -> t -> bool
val ( >= ) : t -> t -> bool
val ( > ) : t -> t -> bool
val compare : t -> t -> int
val equal : t -> t -> bool
val max : t -> t -> t
val min : t -> t -> t
end
module Make (P : COMPARABLE) = struct
include P
let compare = compare
let ( = ) a b = compare a b = 0
let ( <> ) a b = compare a b <> 0
let ( < ) a b = compare a b < 0
let ( <= ) a b = compare a b <= 0
let ( >= ) a b = compare a b >= 0
let ( > ) a b = compare a b > 0
let equal = ( = )
let max x y = if x >= y then x else y
let min x y = if x <= y then x else y
end
module List (P : COMPARABLE) = Make (struct
type t = P.t list
let rec compare xs ys =
match (xs, ys) with
| [], [] -> 0
| [], _ -> -1
| _, [] -> 1
| x :: xs, y :: ys ->
let hd = P.compare x y in
if hd <> 0 then hd else compare xs ys
end)
module Option (P : COMPARABLE) = Make (struct
type t = P.t option
let compare xs ys =
match (xs, ys) with
| None, None -> 0
| None, _ -> -1
| _, None -> 1
| Some x, Some y -> P.compare x y
end)
module Result (Ok : COMPARABLE) (Error : COMPARABLE) = Make (struct
type t = (Ok.t, Error.t) result
(* Note: [Ok _ < Error _] for compatibility with the Stdlib's polymorphic
comparison. *)
let compare ra rb =
match (ra, rb) with
| Ok a, Ok b -> Ok.compare a b
| Error a, Error b -> Error.compare a b
| Ok _, Error _ -> -1
| Error _, Ok _ -> 1
end)
module Char = Make (Char)
module Bool = Make (struct
type t = bool
let compare = Stdlib.compare
end)
module Int = struct
type t = int
(**
Integer comparisons are ubiquitous and must be efficiently
compiled. The OCaml compiler provides the following builtin
externals to make sure that aliases to integer comparisons are
properly detected.
Moving from the generic comparison, which ultimately calls the C
function caml_compare, to these builtins divides execution time
by one or two orders of magnitude.
This optimization is especially important in critical routines
like the gas update and the check for the gas exhaustion of the
Michelson runtime.
References:
-----------
- https://gitlab.com/-/snippets/2031392
- https://tarides.com/blog/2019-09-13-decompress-experiences-with-ocaml-optimization
- https://blog.janestreet.com/the-perils-of-polymorphic-compare/
*)
external ( = ) : int -> int -> bool = "%equal"
external ( <> ) : int -> int -> bool = "%notequal"
external ( < ) : int -> int -> bool = "%lessthan"
external ( > ) : int -> int -> bool = "%greaterthan"
external ( <= ) : int -> int -> bool = "%lessequal"
external ( >= ) : int -> int -> bool = "%greaterequal"
external compare : int -> int -> int = "%compare"
external equal : int -> int -> bool = "%equal"
let max x y = if x >= y then x else y
let min x y = if x <= y then x else y
end
module Int32 = Make (Int32)
module Int64 = Make (Int64)
module MakeUnsigned
(Int : S) (Z : sig
val zero : Int.t
end) =
struct
type t = Int.t
let compare va vb =
Int.(
if va >= Z.zero then if vb >= Z.zero then compare va vb else -1
else if vb >= Z.zero then 1
else compare va vb)
let ( = ) = (( = ) : t -> t -> bool)
let ( <> ) = (( <> ) : t -> t -> bool)
let ( < ) a b =
Int.(if Z.zero <= a then a < b || b < Z.zero else b < Z.zero && a < b)
let ( <= ) a b =
Int.(if Z.zero <= a then a <= b || b < Z.zero else b < Z.zero && a <= b)
let ( >= ) a b = b <= a
let ( > ) a b = b < a
let equal = ( = )
let max x y = if x >= y then x else y
let min x y = if x <= y then x else y
end
module Uint32 =
MakeUnsigned
(Int32)
(struct
let zero = 0l
end)
module Uint64 =
MakeUnsigned
(Int64)
(struct
let zero = 0L
end)
module Float = Make (struct
type t = float
let compare = Stdlib.compare
end)
module String = Make (String)
module Bytes = Make (Bytes)
module Z = struct
type t = Z.t
include Z.Compare
let compare = Z.compare
let equal = Z.equal
let max = Z.max
let min = Z.min
end
module Q = Q
module List_length_with = struct
let ( = ) l i = Stdlib.List.compare_length_with l i = 0
let ( <> ) l i = Stdlib.List.compare_length_with l i <> 0
let ( < ) l i = Stdlib.List.compare_length_with l i < 0
let ( <= ) l i = Stdlib.List.compare_length_with l i <= 0
let ( >= ) l i = Stdlib.List.compare_length_with l i >= 0
let ( > ) l i = Stdlib.List.compare_length_with l i > 0
let compare l i = Stdlib.List.compare_length_with l i
let equal = ( = )
end
module List_lengths = struct
let ( = ) l1 l2 = Stdlib.List.compare_lengths l1 l2 = 0
let ( <> ) l1 l2 = Stdlib.List.compare_lengths l1 l2 <> 0
let ( < ) l1 l2 = Stdlib.List.compare_lengths l1 l2 < 0
let ( <= ) l1 l2 = Stdlib.List.compare_lengths l1 l2 <= 0
let ( >= ) l1 l2 = Stdlib.List.compare_lengths l1 l2 >= 0
let ( > ) l1 l2 = Stdlib.List.compare_lengths l1 l2 > 0
let compare l1 l2 = Stdlib.List.compare_lengths l1 l2
let equal = ( = )
end
let or_else c f = if c <> 0 then c else f ()