| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT RUN-TIME COMPONENTS -- |
| -- -- |
| -- S Y S T E M . P O O L _ S I Z E -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- $Revision: 1.15 $ |
| -- -- |
| -- Copyright (C) 1992-2001 Free Software Foundation, Inc. -- |
| -- -- |
| -- GNAT is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 2, or (at your option) any later ver- -- |
| -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- |
| -- for more details. You should have received a copy of the GNU General -- |
| -- Public License distributed with GNAT; see file COPYING. If not, write -- |
| -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- |
| -- MA 02111-1307, USA. -- |
| -- -- |
| -- As a special exception, if other files instantiate generics from this -- |
| -- unit, or you link this unit with other files to produce an executable, -- |
| -- this unit does not by itself cause the resulting executable to be -- |
| -- covered by the GNU General Public License. This exception does not -- |
| -- however invalidate any other reasons why the executable file might be -- |
| -- covered by the GNU Public License. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| with System.Storage_Elements; |
| with System.Address_To_Access_Conversions; |
| |
| package body System.Pool_Size is |
| |
| package SSE renames System.Storage_Elements; |
| use type SSE.Storage_Offset; |
| |
| package SC is new Address_To_Access_Conversions (SSE.Storage_Count); |
| |
| SC_Size : constant |
| := SSE.Storage_Count'Object_Size / System.Storage_Unit; |
| |
| package Variable_Size_Management is |
| |
| -- Embedded pool that manages allocation of variable-size data. |
| |
| -- This pool is used as soon as the Elmt_sizS of the pool object is 0. |
| |
| -- Allocation is done on the first chunk long enough for the request. |
| -- Deallocation just puts the freed chunk at the beginning of the list. |
| |
| procedure Initialize (Pool : in out Stack_Bounded_Pool); |
| procedure Allocate |
| (Pool : in out Stack_Bounded_Pool; |
| Address : out System.Address; |
| Storage_Size : SSE.Storage_Count; |
| Alignment : SSE.Storage_Count); |
| |
| procedure Deallocate |
| (Pool : in out Stack_Bounded_Pool; |
| Address : System.Address; |
| Storage_Size : SSE.Storage_Count; |
| Alignment : SSE.Storage_Count); |
| end Variable_Size_Management; |
| |
| package Vsize renames Variable_Size_Management; |
| |
| -------------- |
| -- Allocate -- |
| -------------- |
| |
| procedure Allocate |
| (Pool : in out Stack_Bounded_Pool; |
| Address : out System.Address; |
| Storage_Size : SSE.Storage_Count; |
| Alignment : SSE.Storage_Count) |
| is |
| begin |
| if Pool.Elmt_Size = 0 then |
| Vsize.Allocate (Pool, Address, Storage_Size, Alignment); |
| |
| elsif Pool.First_Free /= 0 then |
| Address := Pool.The_Pool (Pool.First_Free)'Address; |
| Pool.First_Free := SC.To_Pointer (Address).all; |
| |
| elsif |
| Pool.First_Empty <= (Pool.Pool_Size - Pool.Aligned_Elmt_Size + 1) |
| then |
| Address := Pool.The_Pool (Pool.First_Empty)'Address; |
| Pool.First_Empty := Pool.First_Empty + Pool.Aligned_Elmt_Size; |
| |
| else |
| raise Storage_Error; |
| end if; |
| end Allocate; |
| |
| ---------------- |
| -- Deallocate -- |
| ---------------- |
| |
| procedure Deallocate |
| (Pool : in out Stack_Bounded_Pool; |
| Address : System.Address; |
| Storage_Size : SSE.Storage_Count; |
| Alignment : SSE.Storage_Count) |
| is |
| begin |
| if Pool.Elmt_Size = 0 then |
| Vsize.Deallocate (Pool, Address, Storage_Size, Alignment); |
| |
| else |
| SC.To_Pointer (Address).all := Pool.First_Free; |
| Pool.First_Free := Address - Pool.The_Pool'Address + 1; |
| end if; |
| end Deallocate; |
| |
| ---------------- |
| -- Initialize -- |
| ---------------- |
| |
| procedure Initialize (Pool : in out Stack_Bounded_Pool) is |
| Align : constant SSE.Storage_Count := |
| SSE.Storage_Count'Max (SSE.Storage_Count'Alignment, Pool.Alignment); |
| |
| begin |
| if Pool.Elmt_Size = 0 then |
| Vsize.Initialize (Pool); |
| |
| else |
| Pool.First_Free := 0; |
| Pool.First_Empty := 1; |
| |
| -- Compute the size to allocate given the size of the element and |
| -- the possible Alignment clause |
| |
| Pool.Aligned_Elmt_Size := |
| SSE.Storage_Count'Max (SC_Size, |
| ((Pool.Elmt_Size + Align - 1) / Align) * Align); |
| end if; |
| end Initialize; |
| |
| ------------------ |
| -- Storage_Size -- |
| ------------------ |
| |
| function Storage_Size |
| (Pool : Stack_Bounded_Pool) |
| return SSE.Storage_Count |
| is |
| begin |
| return Pool.Pool_Size; |
| end Storage_Size; |
| |
| ------------------------------ |
| -- Variable_Size_Management -- |
| ------------------------------ |
| |
| package body Variable_Size_Management is |
| |
| Minimum_Size : constant := 2 * SC_Size; |
| |
| procedure Set_Size |
| (Pool : Stack_Bounded_Pool; |
| Chunk, Size : SSE.Storage_Count); |
| -- Update the field 'size' of a chunk of available storage |
| |
| procedure Set_Next |
| (Pool : Stack_Bounded_Pool; |
| Chunk, Next : SSE.Storage_Count); |
| -- Update the field 'next' of a chunk of available storage |
| |
| function Size |
| (Pool : Stack_Bounded_Pool; |
| Chunk : SSE.Storage_Count) |
| return SSE.Storage_Count; |
| -- Fetch the field 'size' of a chunk of available storage |
| |
| function Next |
| (Pool : Stack_Bounded_Pool; |
| Chunk : SSE.Storage_Count) |
| return SSE.Storage_Count; |
| -- Fetch the field 'next' of a chunk of available storage |
| |
| function Chunk_Of |
| (Pool : Stack_Bounded_Pool; |
| Addr : System.Address) |
| return SSE.Storage_Count; |
| -- Give the chunk number in the pool from its Address |
| |
| -------------- |
| -- Allocate -- |
| -------------- |
| |
| procedure Allocate |
| (Pool : in out Stack_Bounded_Pool; |
| Address : out System.Address; |
| Storage_Size : SSE.Storage_Count; |
| Alignment : SSE.Storage_Count) |
| is |
| Chunk : SSE.Storage_Count; |
| New_Chunk : SSE.Storage_Count; |
| Prev_Chunk : SSE.Storage_Count; |
| Our_Align : constant SSE.Storage_Count := |
| SSE.Storage_Count'Max (SSE.Storage_Count'Alignment, |
| Alignment); |
| Align_Size : constant SSE.Storage_Count := |
| SSE.Storage_Count'Max ( |
| Minimum_Size, |
| ((Storage_Size + Our_Align - 1) / Our_Align) * |
| Our_Align); |
| |
| begin |
| -- Look for the first big enough chunk |
| |
| Prev_Chunk := Pool.First_Free; |
| Chunk := Next (Pool, Prev_Chunk); |
| |
| while Chunk /= 0 and then Size (Pool, Chunk) < Align_Size loop |
| Prev_Chunk := Chunk; |
| Chunk := Next (Pool, Chunk); |
| end loop; |
| |
| -- Raise storage_error if no big enough chunk available |
| |
| if Chunk = 0 then |
| raise Storage_Error; |
| end if; |
| |
| -- When the chunk is bigger than what is needed, take appropraite |
| -- amount and build a new shrinked chunk with the remainder. |
| |
| if Size (Pool, Chunk) - Align_Size > Minimum_Size then |
| New_Chunk := Chunk + Align_Size; |
| Set_Size (Pool, New_Chunk, Size (Pool, Chunk) - Align_Size); |
| Set_Next (Pool, New_Chunk, Next (Pool, Chunk)); |
| Set_Next (Pool, Prev_Chunk, New_Chunk); |
| |
| -- If the chunk is the right size, just delete it from the chain |
| |
| else |
| Set_Next (Pool, Prev_Chunk, Next (Pool, Chunk)); |
| end if; |
| |
| Address := Pool.The_Pool (Chunk)'Address; |
| end Allocate; |
| |
| -------------- |
| -- Chunk_Of -- |
| -------------- |
| |
| function Chunk_Of |
| (Pool : Stack_Bounded_Pool; |
| Addr : System.Address) |
| return SSE.Storage_Count |
| is |
| begin |
| return 1 + abs (Addr - Pool.The_Pool (1)'Address); |
| end Chunk_Of; |
| |
| ---------------- |
| -- Deallocate -- |
| ---------------- |
| |
| procedure Deallocate |
| (Pool : in out Stack_Bounded_Pool; |
| Address : System.Address; |
| Storage_Size : SSE.Storage_Count; |
| Alignment : SSE.Storage_Count) |
| is |
| Align_Size : constant SSE.Storage_Count := |
| ((Storage_Size + Alignment - 1) / Alignment) * |
| Alignment; |
| Chunk : SSE.Storage_Count := Chunk_Of (Pool, Address); |
| |
| begin |
| -- Attach the freed chunk to the chain |
| |
| Set_Size (Pool, Chunk, |
| SSE.Storage_Count'Max (Align_Size, Minimum_Size)); |
| Set_Next (Pool, Chunk, Next (Pool, Pool.First_Free)); |
| Set_Next (Pool, Pool.First_Free, Chunk); |
| |
| end Deallocate; |
| |
| ---------------- |
| -- Initialize -- |
| ---------------- |
| |
| procedure Initialize (Pool : in out Stack_Bounded_Pool) is |
| begin |
| Pool.First_Free := 1; |
| |
| if Pool.Pool_Size > Minimum_Size then |
| Set_Next (Pool, Pool.First_Free, Pool.First_Free + Minimum_Size); |
| Set_Size (Pool, Pool.First_Free, 0); |
| Set_Size (Pool, Pool.First_Free + Minimum_Size, |
| Pool.Pool_Size - Minimum_Size); |
| Set_Next (Pool, Pool.First_Free + Minimum_Size, 0); |
| end if; |
| end Initialize; |
| |
| ---------- |
| -- Next -- |
| ---------- |
| |
| function Next |
| (Pool : Stack_Bounded_Pool; |
| Chunk : SSE.Storage_Count) |
| return SSE.Storage_Count |
| is |
| begin |
| return SC.To_Pointer (Pool.The_Pool (Chunk + SC_Size)'Address).all; |
| end Next; |
| |
| -------------- |
| -- Set_Next -- |
| -------------- |
| |
| procedure Set_Next |
| (Pool : Stack_Bounded_Pool; |
| Chunk, Next : SSE.Storage_Count) |
| is |
| begin |
| SC.To_Pointer (Pool.The_Pool (Chunk + SC_Size)'Address).all := Next; |
| end Set_Next; |
| |
| -------------- |
| -- Set_Size -- |
| -------------- |
| |
| procedure Set_Size |
| (Pool : Stack_Bounded_Pool; |
| Chunk, Size : SSE.Storage_Count) |
| is |
| begin |
| SC.To_Pointer (Pool.The_Pool (Chunk)'Address).all := Size; |
| end Set_Size; |
| |
| ---------- |
| -- Size -- |
| ---------- |
| |
| function Size |
| (Pool : Stack_Bounded_Pool; |
| Chunk : SSE.Storage_Count) |
| return SSE.Storage_Count |
| is |
| begin |
| return SC.To_Pointer (Pool.The_Pool (Chunk)'Address).all; |
| end Size; |
| |
| end Variable_Size_Management; |
| end System.Pool_Size; |
