| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT RUN-TIME COMPONENTS -- |
| -- -- |
| -- S Y S T E M . P O O L _ S I Z E -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1992-2009, 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 3, 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. -- |
| -- -- |
| -- As a special exception under Section 7 of GPL version 3, you are granted -- |
| -- additional permissions described in the GCC Runtime Library Exception, -- |
| -- version 3.1, as published by the Free Software Foundation. -- |
| -- -- |
| -- You should have received a copy of the GNU General Public License and -- |
| -- a copy of the GCC Runtime Library Exception along with this program; -- |
| -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- GNAT was originally developed by the GNAT team at New York University. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| with System.Soft_Links; |
| |
| with Ada.Unchecked_Conversion; |
| |
| package body System.Pool_Size is |
| |
| package SSE renames System.Storage_Elements; |
| use type SSE.Storage_Offset; |
| |
| -- Even though these storage pools are typically only used by a single |
| -- task, if multiple tasks are declared at the same or a more nested scope |
| -- as the storage pool, there still may be concurrent access. The current |
| -- implementation of Stack_Bounded_Pool always uses a global lock for |
| -- protecting access. This should eventually be replaced by an atomic |
| -- linked list implementation for efficiency reasons. |
| |
| package SSL renames System.Soft_Links; |
| |
| type Storage_Count_Access is access SSE.Storage_Count; |
| function To_Storage_Count_Access is |
| new Ada.Unchecked_Conversion (Address, Storage_Count_Access); |
| |
| 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_Size 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 |
| SSL.Lock_Task.all; |
| |
| 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 := To_Storage_Count_Access (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; |
| |
| SSL.Unlock_Task.all; |
| |
| exception |
| when others => |
| SSL.Unlock_Task.all; |
| raise; |
| 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 |
| SSL.Lock_Task.all; |
| |
| if Pool.Elmt_Size = 0 then |
| Vsize.Deallocate (Pool, Address, Storage_Size, Alignment); |
| |
| else |
| To_Storage_Count_Access (Address).all := Pool.First_Free; |
| Pool.First_Free := Address - Pool.The_Pool'Address + 1; |
| end if; |
| |
| SSL.Unlock_Task.all; |
| exception |
| when others => |
| SSL.Unlock_Task.all; |
| raise; |
| end Deallocate; |
| |
| ---------------- |
| -- Initialize -- |
| ---------------- |
| |
| procedure Initialize (Pool : in out Stack_Bounded_Pool) is |
| |
| -- Define the appropriate alignment for allocations. This is the |
| -- maximum of the requested alignment, and the alignment required |
| -- for Storage_Count values. The latter test is to ensure that we |
| -- can properly reference the linked list pointers for free lists. |
| |
| 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 requirement as defined above. |
| |
| 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 appropriate |
| -- 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 |
| pragma Warnings (Off, Pool); |
| |
| Align_Size : constant SSE.Storage_Count := |
| ((Storage_Size + Alignment - 1) / Alignment) * |
| Alignment; |
| Chunk : constant 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 |
| pragma Warnings (Off); |
| -- Kill alignment warnings, we are careful to make sure |
| -- that the alignment is correct. |
| |
| return To_Storage_Count_Access |
| (Pool.The_Pool (Chunk + SC_Size)'Address).all; |
| |
| pragma Warnings (On); |
| end Next; |
| |
| -------------- |
| -- Set_Next -- |
| -------------- |
| |
| procedure Set_Next |
| (Pool : Stack_Bounded_Pool; |
| Chunk, Next : SSE.Storage_Count) |
| is |
| begin |
| pragma Warnings (Off); |
| -- Kill alignment warnings, we are careful to make sure |
| -- that the alignment is correct. |
| |
| To_Storage_Count_Access |
| (Pool.The_Pool (Chunk + SC_Size)'Address).all := Next; |
| |
| pragma Warnings (On); |
| end Set_Next; |
| |
| -------------- |
| -- Set_Size -- |
| -------------- |
| |
| procedure Set_Size |
| (Pool : Stack_Bounded_Pool; |
| Chunk, Size : SSE.Storage_Count) |
| is |
| begin |
| pragma Warnings (Off); |
| -- Kill alignment warnings, we are careful to make sure |
| -- that the alignment is correct. |
| |
| To_Storage_Count_Access |
| (Pool.The_Pool (Chunk)'Address).all := Size; |
| |
| pragma Warnings (On); |
| end Set_Size; |
| |
| ---------- |
| -- Size -- |
| ---------- |
| |
| function Size |
| (Pool : Stack_Bounded_Pool; |
| Chunk : SSE.Storage_Count) return SSE.Storage_Count |
| is |
| begin |
| pragma Warnings (Off); |
| -- Kill alignment warnings, we are careful to make sure |
| -- that the alignment is correct. |
| |
| return To_Storage_Count_Access (Pool.The_Pool (Chunk)'Address).all; |
| |
| pragma Warnings (On); |
| end Size; |
| |
| end Variable_Size_Management; |
| end System.Pool_Size; |
