diff options
Diffstat (limited to 'gcc/ada/s-rannum.adb')
| -rw-r--r-- | gcc/ada/s-rannum.adb | 86 |
1 files changed, 37 insertions, 49 deletions
diff --git a/gcc/ada/s-rannum.adb b/gcc/ada/s-rannum.adb index 87408c30804..5065910eb39 100644 --- a/gcc/ada/s-rannum.adb +++ b/gcc/ada/s-rannum.adb @@ -95,21 +95,6 @@ use Ada; package body System.Random_Numbers is - ------------------------- - -- Implementation Note -- - ------------------------- - - -- The design of this spec is a bit awkward, as a result of Ada 95 not - -- permitting in-out parameters for function formals (most naturally - -- Generator values would be passed this way). In pure Ada 95, the only - -- solution would be to add a self-referential component to the generator - -- allowing access to the generator object from inside the function. This - -- would work because the generator is limited, which prevents any copy. - - -- This is a bit heavy, so what we do is to use Unrestricted_Access to - -- get a pointer to the state in the passed Generator. This works because - -- Generator is a limited type and will thus always be passed by reference. - Y2K : constant Calendar.Time := Calendar.Time_Of (Year => 2000, Month => 1, Day => 1, Seconds => 0.0); @@ -168,7 +153,7 @@ package body System.Random_Numbers is -- Local Subprograms -- ----------------------- - procedure Init (Gen : out Generator; Initiator : Unsigned_32); + procedure Init (Gen : Generator; Initiator : Unsigned_32); -- Perform a default initialization of the state of Gen. The resulting -- state is identical for identical values of Initiator. @@ -192,7 +177,7 @@ package body System.Random_Numbers is ------------ function Random (Gen : Generator) return Unsigned_32 is - G : Generator renames Gen'Unrestricted_Access.all; + G : Generator renames Gen.Writable.Self.all; Y : State_Val; I : Integer; -- should avoid use of identifier I ??? @@ -498,23 +483,23 @@ package body System.Random_Numbers is -- Reset -- ----------- - procedure Reset (Gen : out Generator) is + procedure Reset (Gen : Generator) is X : constant Unsigned_32 := Unsigned_32 ((Calendar.Clock - Y2K) * 64.0); begin Init (Gen, X); end Reset; - procedure Reset (Gen : out Generator; Initiator : Integer_32) is + procedure Reset (Gen : Generator; Initiator : Integer_32) is begin Init (Gen, To_Unsigned (Initiator)); end Reset; - procedure Reset (Gen : out Generator; Initiator : Unsigned_32) is + procedure Reset (Gen : Generator; Initiator : Unsigned_32) is begin Init (Gen, Initiator); end Reset; - procedure Reset (Gen : out Generator; Initiator : Integer) is + procedure Reset (Gen : Generator; Initiator : Integer) is begin pragma Warnings (Off, "condition is always *"); -- This is probably an unnecessary precaution against future change, but @@ -539,27 +524,27 @@ package body System.Random_Numbers is pragma Warnings (On, "condition is always *"); end Reset; - procedure Reset (Gen : out Generator; Initiator : Initialization_Vector) is + procedure Reset (Gen : Generator; Initiator : Initialization_Vector) is + G : Generator renames Gen.Writable.Self.all; I, J : Integer; begin - Init (Gen, Seed1); + Init (G, Seed1); I := 1; J := 0; if Initiator'Length > 0 then for K in reverse 1 .. Integer'Max (N, Initiator'Length) loop - Gen.S (I) := - (Gen.S (I) - xor ((Gen.S (I - 1) xor Shift_Right (Gen.S (I - 1), 30)) - * Mult1)) + G.S (I) := + (G.S (I) xor ((G.S (I - 1) + xor Shift_Right (G.S (I - 1), 30)) * Mult1)) + Initiator (J + Initiator'First) + Unsigned_32 (J); I := I + 1; J := J + 1; if I >= N then - Gen.S (0) := Gen.S (N - 1); + G.S (0) := G.S (N - 1); I := 1; end if; @@ -570,39 +555,42 @@ package body System.Random_Numbers is end if; for K in reverse 1 .. N - 1 loop - Gen.S (I) := - (Gen.S (I) xor ((Gen.S (I - 1) - xor Shift_Right (Gen.S (I - 1), 30)) * Mult2)) + G.S (I) := + (G.S (I) xor ((G.S (I - 1) + xor Shift_Right (G.S (I - 1), 30)) * Mult2)) - Unsigned_32 (I); I := I + 1; if I >= N then - Gen.S (0) := Gen.S (N - 1); + G.S (0) := G.S (N - 1); I := 1; end if; end loop; - Gen.S (0) := Upper_Mask; + G.S (0) := Upper_Mask; end Reset; - procedure Reset (Gen : out Generator; From_State : Generator) is + procedure Reset (Gen : Generator; From_State : Generator) is + G : Generator renames Gen.Writable.Self.all; begin - Gen.S := From_State.S; - Gen.I := From_State.I; + G.S := From_State.S; + G.I := From_State.I; end Reset; - procedure Reset (Gen : out Generator; From_State : State) is + procedure Reset (Gen : Generator; From_State : State) is + G : Generator renames Gen.Writable.Self.all; begin - Gen.I := 0; - Gen.S := From_State; + G.I := 0; + G.S := From_State; end Reset; - procedure Reset (Gen : out Generator; From_Image : String) is + procedure Reset (Gen : Generator; From_Image : String) is + G : Generator renames Gen.Writable.Self.all; begin - Gen.I := 0; + G.I := 0; for J in 0 .. N - 1 loop - Gen.S (J) := Extract_Value (From_Image, J); + G.S (J) := Extract_Value (From_Image, J); end loop; end Reset; @@ -670,17 +658,18 @@ package body System.Random_Numbers is -- Init -- ---------- - procedure Init (Gen : out Generator; Initiator : Unsigned_32) is + procedure Init (Gen : Generator; Initiator : Unsigned_32) is + G : Generator renames Gen.Writable.Self.all; begin - Gen.S (0) := Initiator; + G.S (0) := Initiator; for I in 1 .. N - 1 loop - Gen.S (I) := - Mult0 * (Gen.S (I - 1) xor Shift_Right (Gen.S (I - 1), 30)) + - Unsigned_32 (I); + G.S (I) := + (G.S (I - 1) xor Shift_Right (G.S (I - 1), 30)) * Mult0 + + Unsigned_32 (I); end loop; - Gen.I := 0; + G.I := 0; end Init; ------------------ @@ -706,5 +695,4 @@ package body System.Random_Numbers is begin return State_Val'Value (S (Start .. Start + Image_Numeral_Length - 1)); end Extract_Value; - end System.Random_Numbers; |
