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206 | --
-- Copyright (C) 2022-2023, AdaCore
--
-- SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
--
with Ada.Strings.Wide_Wide_Unbounded;
with Ada.Unchecked_Deallocation;
with VSS.Characters;
with VSS.Strings.Character_Iterators;
with VSS.Unicode;
package body VSS.Implementation.Windows.String_Utilities is
use type Interfaces.C.size_t;
function wcslen (Item : LPWSTR) return Interfaces.C.size_t
with Import, Convention => C, External_Name => "wcslen";
----------
-- Free --
----------
procedure Free (Item : in out char16_array_access) is
procedure Internal is
new Ada.Unchecked_Deallocation
(Interfaces.C.char16_array, char16_array_access);
begin
Internal (Item);
end Free;
------------------------
-- From_Native_String --
------------------------
function From_Native_String
(Item : Interfaces.C.char16_array) return VSS.Strings.Virtual_String
is
procedure Free is
new Ada.Unchecked_Deallocation
(Wide_Wide_String,
Ada.Strings.Wide_Wide_Unbounded.Wide_Wide_String_Access);
High_Surrogate_First : constant := 16#D800#;
Low_Surrogate_First : constant := 16#DC00#;
Surrogate_Kind_Mask : constant := 16#FC00#;
Masked_High_Surrogate : constant := 16#D800#;
UCS4_Fixup : constant
:= High_Surrogate_First * 16#400# + Low_Surrogate_First - 16#1_0000#;
-- When code point is encoded as pair of surrogates its value computed
-- as:
--
-- C := (S (J) - HB) << 10 + S (J + 1) - LB + 0x10000
--
-- to optimize number of computations this expression is transformed to
--
-- C := S (J) << 10 + S (J + 1) - (HB << 10 + LB - 0x10000)
-- ^^^^^^^^^^^^^^^^^^^^^^^^^
-- This constant represents constant part of the expression.
Aux : Ada.Strings.Wide_Wide_Unbounded.Wide_Wide_String_Access :=
new Wide_Wide_String (1 .. Item'Length);
Last : Natural := 0;
Index : Interfaces.C.size_t := Item'First;
begin
while Index <= Item'Last loop
declare
use type Interfaces.Unsigned_32;
C : Interfaces.Unsigned_32 :=
Interfaces.C.char16_t'Pos (Item (Index));
begin
Index := Index + 1;
if (C and Surrogate_Kind_Mask) = Masked_High_Surrogate then
C :=
C * 16#400#
+ Interfaces.C.char16_t'Pos (Item (Index))
- UCS4_Fixup;
Index := Index + 1;
end if;
exit when C = 16#0000#;
Last := Last + 1;
Aux (Last) := Wide_Wide_Character'Val (C);
end;
end loop;
return Result : constant VSS.Strings.Virtual_String :=
VSS.Strings.To_Virtual_String (Aux (1 .. Last))
do
Free (Aux);
end return;
exception
when others =>
Free (Aux);
raise;
end From_Native_String;
------------------------
-- From_Native_String --
------------------------
function From_Native_String
(Item : LPWSTR) return VSS.Strings.Virtual_String
is
Aux : constant Interfaces.C.char16_array (0 .. wcslen (Item) - 1)
with Import, Convention => C, Address => Item.all'Address;
begin
return From_Native_String (Aux);
end From_Native_String;
------------------------------
-- New_Native_String_Buffer --
------------------------------
function New_Native_String_Buffer
(Size : Interfaces.C.size_t) return char16_array_access is
begin
return new Interfaces.C.char16_array (0 .. Size);
end New_Native_String_Buffer;
--------------------------
-- To_New_Native_String --
--------------------------
function To_New_Native_String
(Item : VSS.Strings.Virtual_String) return char16_array_access
is
use type VSS.Unicode.Code_Point;
-- This conversion function process data without use of primary stack,
-- thus prevent crashes on conversion of big data.
-- It takes into account that content of Virtual_String is always valid,
-- there are no any checks for invalid ranges of code points here.
High_Surrogate_First : constant := 16#D800#;
Low_Surrogate_First : constant := 16#DC00#;
High_Surrogate_First_Store : constant
:= High_Surrogate_First - 16#1_0000# / 16#400#;
-- Code point is converted to surrogate pair as:
--
-- S (J) := HB + (C - 0x10000) >> 10
-- S (J + 1) := LB + (C - 0x10000) & 0x3FF
--
-- to optimize implementation they are rewritten as:
--
-- S (J + 1) := LB + C & 0x3FF
-- S (J) := (HB - 0x10000 >> 10) + C >> 10
-- ^^^^^^^^^^^^^^^^^^^^
-- This constant represents constant part of the expression.
Result : char16_array_access;
Last : Interfaces.C.size_t := 0;
Position : VSS.Strings.Character_Iterators.Character_Iterator :=
Item.Before_First_Character;
Code : VSS.Unicode.Code_Point;
begin
if not Item.Is_Null then
Result :=
New_Native_String_Buffer
(Interfaces.C.size_t (Item.Character_Length) * 2);
while Position.Forward loop
Code := VSS.Characters.Virtual_Character'Pos (Position.Element);
if Code <= 16#FFFF# then
Result (Last) := Interfaces.C.char16_t'Val (Code);
Last := Last + 1;
else
Result (Last) :=
Interfaces.C.char16_t'Val
(High_Surrogate_First_Store + Code / 16#400#);
Last := Last + 1;
Result (Last) :=
Interfaces.C.char16_t'Val
(Low_Surrogate_First + Code mod 16#400#);
Last := Last + 1;
end if;
end loop;
Result (Last) := Interfaces.C.char16_t'Val (0);
end if;
return Result;
exception
when others =>
Free (Result);
raise;
end To_New_Native_String;
end VSS.Implementation.Windows.String_Utilities;
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