hcl/lib2/h3-arrays.adb

393 lines
13 KiB
Ada

with Ada.Unchecked_Deallocation;
package body H3.Arrays is
BUFFER_ALIGN: constant := 128; -- TODO: change it to a reasonably large value.
function Get_Terminator_Length (Obj: in Elastic_Array) return System_Zero_Or_One is
begin
-- Obj unused
return Terminator_Length;
end Get_Terminator_Length;
function Get_Terminator_Value (Obj: in Elastic_Array) return Item_Type is
begin
-- Obj unused
return Terminator_Value;
end Get_Terminator_Value;
function To_Item_Array (Obj: in Elastic_Array) return Item_Array is
begin
return Obj.Buffer.Slot(Obj.Buffer.Slot'First .. Obj.Buffer.Last);
end To_Item_Array;
-- return the buffer capacity excluding the terminator
function Get_Capacity (Obj: in Elastic_Array) return System_Size is
begin
return Obj.Buffer.Slot'Length - Terminator_Length;
end Get_Capacity;
-- private. return the buffer capacity including the terminator
function Get_Hard_Capacity (Obj: in Elastic_Array) return System_Size is
begin
return Obj.Buffer.Slot'Length;
end Get_Hard_Capacity;
pragma Inline (Get_Hard_Capacity);
function Get_Length (Obj: in Elastic_Array) return System_Size is
begin
return 1 + Obj.Buffer.Last - Obj.Buffer.Slot'First;
end Get_Length;
function Get_First_Index (Obj: in Elastic_Array) return System_Size is
begin
return Obj.Buffer.Slot'First;
end Get_First_Index;
function Get_Last_Index (Obj: in Elastic_Array) return System_Size is
begin
return Obj.Buffer.Last;
end Get_Last_Index;
function Get_Item (Obj: in Elastic_Array; Pos: in System_Index) return Item_Type is
begin
return Obj.Buffer.Slot(Pos);
end Get_Item;
-- unsafe as it exposes the internal buffer which can go away.
-- assume the system address is equal to the thin pointer in size.
function Get_Slot_Pointer (Obj: in Elastic_Array) return Thin_Item_Array_Pointer is
A: System.Address := Obj.Buffer.Slot(Obj.Buffer.Slot'First)'Address;
P: Thin_Item_Array_Pointer;
for P'Address use A'Address;
pragma Import (Ada, P);
begin
return P;
end Get_Slot_Pointer;
function Is_Shared(Obj: in Elastic_Array) return Boolean is
begin
return Obj.Buffer /= Empty_Buffer'Access and then Obj.Buffer.Refs > 1;
end Is_Shared;
procedure Ref_Buffer (Buf: in Buffer_Pointer) is
begin
if Buf /= Empty_Buffer'Access then
Buf.Refs := Buf.Refs + 1;
end if;
end Ref_Buffer;
procedure Unref_Buffer (Buf: in out Buffer_Pointer) is
begin
if Buf /= Empty_Buffer'Access then
if Buf.Refs = 1 then
declare
procedure Free is new Ada.Unchecked_Deallocation(Buffer_Record, Buffer_Pointer);
begin
Free (Buf);
end;
Buf := Empty_Buffer'Access;
else
Buf.Refs := Buf.Refs - 1;
end if;
end if;
end Unref_Buffer;
function New_Buffer_Container (Hard_Capa: in System_Size) return Elastic_Array is
Tmp: Elastic_Array;
begin
Tmp.Buffer := new Buffer_Record(Hard_Capa);
Tmp.Buffer.Refs := 1;
return Tmp;
end New_Buffer_Container;
-- prepare the buffer for writing
procedure Prepare_Buffer (Obj: in out Elastic_Array) is
Tmp: Elastic_Array;
begin
if Obj.Buffer /= Empty_Buffer'Access then
if Is_Shared(Obj) then
-- The code like this doesn't work correctly in terms of finalization.
-- The buffer pointer held inside a finalization controlled record must be
-- manipluated through the record itself. otherwise, the Adjust and Finalize
-- calls goes incompatible with the reference counting implementation.
-- It is because finalization is set on the record rather than the buffer pointer.
--Tmp: Buffer_Pointer;
--Tmp := new Buffer_Record(Get_Hard_Capacity(Obj));
--Tmp.Slot := Obj.Buffer.Slot;
--Tmp.Last := Obj.Buffer.Last;
--Tmp.Refs := 1;
--Unref_Buffer (Obj.Buffer);
--Obj.Buffer := Tmp;
Tmp := Obj;
Obj := New_Buffer_Container(Get_Hard_Capacity(Obj));
Obj.Buffer.Slot := Tmp.Buffer.Slot;
Obj.Buffer.Last := Tmp.Buffer.Last;
end if;
end if;
end Prepare_Buffer;
-- prepare the buffer for writing
procedure Prepare_Buffer (Obj: in out Elastic_Array; Req_Hard_Capa: in System_Size; Shift_Pos: in System_Size := 0; Shift_Size: in System_Size := 0; Shift_Dir: in Direction := DIRECTION_FORWARD) is
Tmp: Elastic_Array;
First, Last: System_Size;
Hard_Capa: System_Size;
begin
First := Get_First_Index(Obj);
Last := Get_Last_Index(Obj);
if Obj.Buffer /= Empty_Buffer'Access and then Is_Shared(Obj) then
if Req_Hard_Capa < Get_Hard_Capacity(Obj) then
Hard_Capa := Get_Hard_Capacity(Obj);
else
Hard_Capa := Req_Hard_Capa;
end if;
Tmp := Obj;
Obj := New_Buffer_Container(Hard_Capa);
goto COPY_OVER;
else
if Req_Hard_Capa > Get_Hard_Capacity(Obj) then
Tmp := Obj;
Obj := New_Buffer_Container(Req_Hard_Capa);
goto COPY_OVER;
elsif Shift_Pos > 0 then
Tmp := Obj;
goto COPY_OVER_WITH_SHIFT;
else
-- no shift, no change in the buffer
null;
end if;
end if;
return;
<<COPY_OVER>>
if Shift_Pos <= 0 then
-- no shift is required. copy the entire Array including th
Obj.Buffer.Slot(First .. Last + Terminator_Length) := Tmp.Buffer.Slot(First .. Last + Terminator_Length);
Obj.Buffer.Last := Last;
return;
end if;
<<COPY_OVER_WITH_SHIFT>>
-- it is an internal function. perform no sanity check.
-- if Shift_Pos or Shift_Size is beyond the allocated capacity,
-- it will end up in an exception.
if Shift_Dir = DIRECTION_BACKWARD then
declare
Mid: constant System_Size := Shift_Pos - Shift_Size;
begin
Obj.Buffer.Slot(First .. Mid) := Tmp.Buffer.Slot(First .. Mid);
Obj.Buffer.Slot(Mid + 1 .. Last - Shift_Size + Terminator_Length) := Tmp.Buffer.Slot(Shift_Pos + 1 .. Last + Terminator_Length);
Obj.Buffer.Last := Last - Shift_Size;
end;
else
Obj.Buffer.Slot(First .. Shift_Pos - 1) := Tmp.Buffer.Slot(First .. Shift_Pos - 1);
Obj.Buffer.Slot(Shift_Pos + Shift_Size .. Last + Shift_Size + Terminator_Length) := Tmp.Buffer.Slot(Shift_Pos .. Last + Terminator_Length);
Obj.Buffer.Last := Last + Shift_Size;
end if;
end Prepare_Buffer;
procedure Clear (Obj: in out Elastic_Array) is
begin
Prepare_Buffer (Elastic_Array(Obj));
Obj.Buffer.Last := Get_First_Index(Obj) - 1;
Obj.Buffer.Slot(Get_First_Index(Obj) .. Get_First_Index(Obj) + Terminator_Length - 1) := (others => Terminator_Value);
end Clear;
procedure Purge (Obj: in out Elastic_Array) is
begin
Unref_Buffer (Obj.Buffer);
Obj.Buffer := Empty_Buffer'Access;
end Purge;
function Calc_Inc_Capa (Obj: in Elastic_Array; Inc: in System_Size) return System_Size is
begin
return H3.Align(Get_Length(Obj) + Inc + Terminator_Length, BUFFER_ALIGN);
end Calc_Inc_Capa;
procedure Insert (Obj: in out Elastic_Array; Pos: in System_Index; V: in Item_Type; Repeat: in System_Size := 1) is
Act_Pos: System_Index := Pos;
Act_Inc: constant System_Size := Repeat;
begin
if Act_Pos > Obj.Buffer.Last then
Act_Pos := Obj.Buffer.Last + 1;
end if;
Prepare_Buffer (Elastic_Array(Obj), Calc_Inc_Capa(Obj, Act_Inc), Act_Pos, Act_Inc);
Obj.Buffer.Slot(Act_Pos .. Act_Pos + Act_Inc - 1) := (others => V);
end Insert;
procedure Insert (Obj: in out Elastic_Array; Pos: in System_Index; V: in Item_Array) is
Act_Pos: System_Index := Pos;
begin
if Act_Pos > Obj.Buffer.Last then
Act_Pos := Obj.Buffer.Last + 1;
end if;
Prepare_Buffer (Elastic_Array(Obj), Calc_Inc_Capa(Obj, V'Length), Act_Pos, V'Length);
Obj.Buffer.Slot(Act_Pos .. Act_Pos + V'Length - 1) := V;
end Insert;
-- TODO: operator "&" that returns a new Elastic_Array
procedure Append (Obj: in out Elastic_Array; V: in Item_Type; Repeat: in System_Size := 1) is
begin
Insert (Obj, Get_Last_Index(Obj) + 1, V, Repeat);
end Append;
procedure Append (Obj: in out Elastic_Array; V: in Item_Array) is
begin
Insert (Obj, Get_Last_Index(Obj) + 1, V);
end Append;
procedure Prepend (Obj: in out Elastic_Array; V: in Item_Type; Repeat: in System_Size := 1) is
begin
Insert (Obj, Get_First_Index(Obj), V, Repeat);
end Prepend;
procedure Prepend (Obj: in out Elastic_Array; V: in Item_Array) is
begin
Insert (Obj, Get_First_Index(Obj), V);
end Prepend;
procedure Replace (Obj: in out Elastic_Array; From_Pos: in System_Index; To_Pos: in System_Size; V: in Item_Type; Repeat: in System_Size := 1) is
Act_To_Pos, Repl_Len: System_Size;
begin
if From_Pos <= To_Pos and then From_Pos <= Obj.Buffer.Last then
Act_To_Pos := To_Pos;
if Act_To_Pos > Obj.Buffer.Last then
Act_To_Pos := Obj.Buffer.Last;
end if;
Repl_Len := Act_To_Pos - From_Pos + 1;
if Repeat < Repl_Len then
Prepare_Buffer (Elastic_Array(Obj), Get_Hard_Capacity(Obj), Act_To_Pos, Repl_Len - Repeat, DIRECTION_BACKWARD);
Act_To_Pos := From_Pos + Repeat - 1;
elsif Repeat > Repl_Len then
Prepare_Buffer (Elastic_Array(Obj), Calc_Inc_Capa(Obj, Repeat - Repl_Len), From_Pos, Repeat - Repl_Len, DIRECTION_FORWARD);
Act_To_Pos := From_Pos + Repeat - 1;
else
Prepare_Buffer (Elastic_Array(Obj));
end if;
Obj.Buffer.Slot(From_Pos .. Act_To_Pos) := (others => V);
end if;
end Replace;
procedure Replace (Obj: in out Elastic_Array; From_Pos: in System_Index; To_Pos: in System_Size; V: in Item_Array) is
Act_To_Pos, Repl_Len: System_Size;
begin
if From_Pos <= To_Pos and then From_Pos <= Obj.Buffer.Last then
Act_To_Pos := To_Pos;
if Act_To_Pos > Obj.Buffer.Last then
Act_To_Pos := Obj.Buffer.Last;
end if;
Repl_Len := Act_To_Pos - From_Pos + 1;
if V'Length < Repl_Len then
Prepare_Buffer (Elastic_Array(Obj), Get_Hard_Capacity(Obj), Act_To_Pos, Repl_Len - V'Length, DIRECTION_BACKWARD);
Act_To_Pos := From_Pos + V'Length - 1;
elsif V'Length > Repl_Len then
Prepare_Buffer (Elastic_Array(Obj), Calc_Inc_Capa(Obj, V'Length - Repl_Len), From_Pos, V'Length - Repl_Len, DIRECTION_FORWARD);
Act_To_Pos := From_Pos + V'Length - 1;
else
Prepare_Buffer (Elastic_Array(Obj));
end if;
Obj.Buffer.Slot(From_Pos .. Act_To_Pos) := V;
end if;
end Replace;
procedure Delete (Obj: in out Elastic_Array; From_Pos: in System_Index; To_Pos: in System_Size) is
Act_To_Pos: System_Size;
begin
if From_Pos <= To_Pos and then From_Pos <= Obj.Buffer.Last then
Act_To_Pos := To_Pos;
if Act_To_Pos > Obj.Buffer.Last then
Act_To_Pos := Obj.Buffer.Last;
end if;
Prepare_Buffer (Elastic_Array(Obj), Get_Hard_Capacity(Obj), Act_To_Pos, Act_To_Pos - From_Pos + 1, DIRECTION_BACKWARD);
end if;
end Delete;
function Find (Obj: in Elastic_Array; V: in Item_Type; Start_Pos: in System_Index; Find_Dir: in Direction := DIRECTION_FORWARD) return System_Size is
Act_Start_Pos: System_Index := Start_Pos;
begin
if Find_Dir = DIRECTION_FORWARD then
if Act_Start_Pos < Get_First_Index(Obj) then
Act_Start_Pos := Get_First_Index(Obj);
end if;
for i in Act_Start_Pos .. Get_Last_Index(Obj) loop
if Get_Item(Obj, i) = V then
return i;
end if;
end loop;
else
if Act_Start_Pos > Get_Last_Index(Obj) then
Act_Start_Pos := Get_Last_Index(Obj);
end if;
for i in reverse Get_First_Index(Obj) .. Act_Start_Pos loop
if Get_Item(Obj, i) = V then
return i;
end if;
end loop;
end if;
return System_Size'First;
end Find;
function Find (Obj: in Elastic_Array; V: in Item_Array; Start_Pos: in System_Index; Find_Dir: in Direction := DIRECTION_FORWARD) return System_Size is
End_Pos: System_Size;
begin
if Get_Length(Obj) > 0 and then V'Length > 0 and then V'Length <= Get_Length(Obj) then
End_Pos := Get_Last_Index(Obj) - V'Length + 1;
if Find_Dir = DIRECTION_FORWARD then
for i in Start_Pos .. End_Pos loop
if Obj.Buffer.Slot(i .. i + V'Length - 1) = V then
return i;
end if;
end loop;
else
if Start_Pos < End_Pos then
End_Pos := Start_Pos;
end if;
for i in reverse Get_First_Index(Obj) .. End_Pos loop
if Obj.Buffer.Slot(i .. i + V'Length - 1) = V then
return i;
end if;
end loop;
end if;
end if;
return System_Size'First;
end Find;
function Equals (Obj: in Elastic_Array; Obj2: in Elastic_Array) return Boolean is
begin
return Obj.Buffer = Obj2.Buffer or else Obj.Buffer.Slot(Get_First_Index(Obj) .. Get_Last_Index(Obj)) = Obj2.Buffer.Slot(Get_First_Index(Obj2) .. Get_Last_Index(Obj2));
end Equals;
function Equals (Obj: in Elastic_Array; Obj2: in Item_Array) return Boolean is
begin
return Obj.Buffer.Slot(Get_First_Index(Obj) .. Get_Last_Index(Obj)) = Obj2;
end Equals;
-- ---------------------------------------------------------------------
-- Controlled Management
-- ---------------------------------------------------------------------
procedure Initialize (Obj: in out Elastic_Array) is
begin
-- the Buffer is initialized to Empty_Buffer all the time.
-- there is no need to reference the buffer.
null;
end Initialize;
procedure Adjust (Obj: in out Elastic_Array) is
begin
Ref_Buffer (Obj.Buffer);
end Adjust;
procedure Finalize (Obj: in out Elastic_Array) is
begin
Unref_Buffer (Obj.Buffer);
end Finalize;
end H3.Arrays;