gcc/ada/table.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                                T A B L E                                 --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2017, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 with System;  use System;
  33 with Tree_IO; use Tree_IO;
  34
  35 with System.Memory; use System.Memory;
  36
  37 with Unchecked_Conversion;
  38
  39 package body Table is
  40    package body Table is
  41
  42       function Tree_Get_Table_Address return Address;
  43       --  Return Null_Address if the table length is zero,
  44       --  Table (First)'Address if not.
  45
  46       ----------------------------
  47       -- Tree_Get_Table_Address --
  48       ----------------------------
  49
  50       function Tree_Get_Table_Address return Address is
  51       begin
  52          if Is_Empty then
  53             return Null_Address;
  54          else
  55             return Table (First)'Address;
  56          end if;
  57       end Tree_Get_Table_Address;
  58
  59       ---------------
  60       -- Tree_Read --
  61       ---------------
  62
  63       --  Note: we allocate only the space required to accommodate the data
  64       --  actually written, which means that a Tree_Write/Tree_Read sequence
  65       --  does an implicit Release.
  66
  67       procedure Tree_Read is
  68          Last : Int;
  69       begin
  70          Init;
  71          Tree_Read_Int (Last);
  72          Set_Last (Table_Last_Type (Last));
  73
  74          Tree_Read_Data
  75            (Tree_Get_Table_Address,
  76              (Last - Int (First) + 1) *
  77
  78                --  Note the importance of parenthesizing the following division
  79                --  to avoid the possibility of intermediate overflow.
  80
  81                (Table_Type'Component_Size / Storage_Unit));
  82       end Tree_Read;
  83
  84       ----------------
  85       -- Tree_Write --
  86       ----------------
  87
  88       --  Note: we write out only the currently valid data, not the entire
  89       --  contents of the allocated array. See note above on Tree_Read.
  90
  91       procedure Tree_Write is
  92       begin
  93          Tree_Write_Int (Int (Last));
  94          Tree_Write_Data
  95            (Tree_Get_Table_Address,
  96             (Int (Last - First) + 1) *
  97               (Table_Type'Component_Size / Storage_Unit));
  98       end Tree_Write;
  99
 100    end Table;
 101 end Table;