blob: 8d00d0bedb01a83c6a96ba109a4b3b8b979f55ba [file] [log] [blame]
------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- A D A . S T R I N G S . U N B O U N D E D --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2022, Free Software Foundation, Inc. --
-- --
-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. The copyright notice above, and the license provisions that follow --
-- apply solely to the contents of the part following the private keyword. --
-- --
-- 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. --
-- --
------------------------------------------------------------------------------
-- Preconditions in this unit are meant for analysis only, not for run-time
-- checking, so that the expected exceptions are raised. This is enforced by
-- setting the corresponding assertion policy to Ignore.
pragma Assertion_Policy (Pre => Ignore);
-- This package provides an implementation of Ada.Strings.Unbounded that uses
-- reference counts to implement copy on modification (rather than copy on
-- assignment). This is significantly more efficient on many targets.
-- This version is supported on:
-- - all Alpha platforms
-- - all AARCH64 platforms
-- - all ARM platforms
-- - all ia64 platforms
-- - all PowerPC platforms
-- - all SPARC V9 platforms
-- - all x86 platforms
-- - all x86_64 platforms
-- This package uses several techniques to increase speed:
-- - Implicit sharing or copy-on-write. An Unbounded_String contains only
-- the reference to the data which is shared between several instances.
-- The shared data is reallocated only when its value is changed and
-- the object mutation can't be used or it is inefficient to use it.
-- - Object mutation. Shared data object can be reused without memory
-- reallocation when all of the following requirements are met:
-- - the shared data object is no longer used by anyone else;
-- - the size is sufficient to store the new value;
-- - the gap after reuse is less than a defined threshold.
-- - Memory preallocation. Most of used memory allocation algorithms
-- align allocated segments on the some boundary, thus some amount of
-- additional memory can be preallocated without any impact. Such
-- preallocated memory can used later by Append/Insert operations
-- without reallocation.
-- Reference counting uses GCC builtin atomic operations, which allows safe
-- sharing of internal data between Ada tasks. Nevertheless, this does not
-- make objects of Unbounded_String thread-safe: an instance cannot be
-- accessed by several tasks simultaneously.
with Ada.Strings.Maps;
private with Ada.Finalization;
private with System.Atomic_Counters;
private with Ada.Strings.Text_Buffers;
package Ada.Strings.Unbounded with
Initial_Condition => Length (Null_Unbounded_String) = 0
is
pragma Preelaborate;
type Unbounded_String is private with
Default_Initial_Condition => Length (Unbounded_String) = 0;
pragma Preelaborable_Initialization (Unbounded_String);
Null_Unbounded_String : constant Unbounded_String;
function Length (Source : Unbounded_String) return Natural with
Global => null;
type String_Access is access all String;
procedure Free (X : in out String_Access);
--------------------------------------------------------
-- Conversion, Concatenation, and Selection Functions --
--------------------------------------------------------
function To_Unbounded_String
(Source : String) return Unbounded_String
with
Post => Length (To_Unbounded_String'Result) = Source'Length,
Global => null;
function To_Unbounded_String
(Length : Natural) return Unbounded_String
with
Post =>
Ada.Strings.Unbounded.Length (To_Unbounded_String'Result) = Length,
Global => null;
function To_String (Source : Unbounded_String) return String with
Post => To_String'Result'Length = Length (Source),
Global => null;
procedure Set_Unbounded_String
(Target : out Unbounded_String;
Source : String)
with
Global => null;
pragma Ada_05 (Set_Unbounded_String);
procedure Append
(Source : in out Unbounded_String;
New_Item : Unbounded_String)
with
Pre => Length (New_Item) <= Natural'Last - Length (Source),
Post => Length (Source) = Length (Source)'Old + Length (New_Item),
Global => null;
procedure Append
(Source : in out Unbounded_String;
New_Item : String)
with
Pre => New_Item'Length <= Natural'Last - Length (Source),
Post => Length (Source) = Length (Source)'Old + New_Item'Length,
Global => null;
procedure Append
(Source : in out Unbounded_String;
New_Item : Character)
with
Pre => Length (Source) < Natural'Last,
Post => Length (Source) = Length (Source)'Old + 1,
Global => null;
function "&"
(Left : Unbounded_String;
Right : Unbounded_String) return Unbounded_String
with
Pre => Length (Right) <= Natural'Last - Length (Left),
Post => Length ("&"'Result) = Length (Left) + Length (Right),
Global => null;
function "&"
(Left : Unbounded_String;
Right : String) return Unbounded_String
with
Pre => Right'Length <= Natural'Last - Length (Left),
Post => Length ("&"'Result) = Length (Left) + Right'Length,
Global => null;
function "&"
(Left : String;
Right : Unbounded_String) return Unbounded_String
with
Pre => Left'Length <= Natural'Last - Length (Right),
Post => Length ("&"'Result) = Left'Length + Length (Right),
Global => null;
function "&"
(Left : Unbounded_String;
Right : Character) return Unbounded_String
with
Pre => Length (Left) < Natural'Last,
Post => Length ("&"'Result) = Length (Left) + 1,
Global => null;
function "&"
(Left : Character;
Right : Unbounded_String) return Unbounded_String
with
Pre => Length (Right) < Natural'Last,
Post => Length ("&"'Result) = Length (Right) + 1,
Global => null;
function Element
(Source : Unbounded_String;
Index : Positive) return Character
with
Pre => Index <= Length (Source),
Global => null;
procedure Replace_Element
(Source : in out Unbounded_String;
Index : Positive;
By : Character)
with
Pre => Index <= Length (Source),
Post => Length (Source) = Length (Source)'Old,
Global => null;
function Slice
(Source : Unbounded_String;
Low : Positive;
High : Natural) return String
with
Pre => Low - 1 <= Length (Source) and then High <= Length (Source),
Post => Slice'Result'Length = Natural'Max (0, High - Low + 1),
Global => null;
function Unbounded_Slice
(Source : Unbounded_String;
Low : Positive;
High : Natural) return Unbounded_String
with
Pre => Low - 1 <= Length (Source) and then High <= Length (Source),
Post =>
Length (Unbounded_Slice'Result) = Natural'Max (0, High - Low + 1),
Global => null;
pragma Ada_05 (Unbounded_Slice);
procedure Unbounded_Slice
(Source : Unbounded_String;
Target : out Unbounded_String;
Low : Positive;
High : Natural)
with
Pre => Low - 1 <= Length (Source) and then High <= Length (Source),
Post => Length (Target) = Natural'Max (0, High - Low + 1),
Global => null;
pragma Ada_05 (Unbounded_Slice);
function "="
(Left : Unbounded_String;
Right : Unbounded_String) return Boolean
with
Global => null;
function "="
(Left : Unbounded_String;
Right : String) return Boolean
with
Global => null;
function "="
(Left : String;
Right : Unbounded_String) return Boolean
with
Global => null;
function "<"
(Left : Unbounded_String;
Right : Unbounded_String) return Boolean
with
Global => null;
function "<"
(Left : Unbounded_String;
Right : String) return Boolean
with
Global => null;
function "<"
(Left : String;
Right : Unbounded_String) return Boolean
with
Global => null;
function "<="
(Left : Unbounded_String;
Right : Unbounded_String) return Boolean
with
Global => null;
function "<="
(Left : Unbounded_String;
Right : String) return Boolean
with
Global => null;
function "<="
(Left : String;
Right : Unbounded_String) return Boolean
with
Global => null;
function ">"
(Left : Unbounded_String;
Right : Unbounded_String) return Boolean
with
Global => null;
function ">"
(Left : Unbounded_String;
Right : String) return Boolean
with
Global => null;
function ">"
(Left : String;
Right : Unbounded_String) return Boolean
with
Global => null;
function ">="
(Left : Unbounded_String;
Right : Unbounded_String) return Boolean
with
Global => null;
function ">="
(Left : Unbounded_String;
Right : String) return Boolean
with
Global => null;
function ">="
(Left : String;
Right : Unbounded_String) return Boolean
with
Global => null;
------------------------
-- Search Subprograms --
------------------------
function Index
(Source : Unbounded_String;
Pattern : String;
Going : Direction := Forward;
Mapping : Maps.Character_Mapping := Maps.Identity) return Natural
with
Pre => Pattern'Length /= 0,
Global => null;
function Index
(Source : Unbounded_String;
Pattern : String;
Going : Direction := Forward;
Mapping : Maps.Character_Mapping_Function) return Natural
with
Pre => Pattern'Length /= 0,
Global => null;
function Index
(Source : Unbounded_String;
Set : Maps.Character_Set;
Test : Membership := Inside;
Going : Direction := Forward) return Natural
with
Global => null;
function Index
(Source : Unbounded_String;
Pattern : String;
From : Positive;
Going : Direction := Forward;
Mapping : Maps.Character_Mapping := Maps.Identity) return Natural
with
Pre => (if Length (Source) /= 0 then From <= Length (Source))
and then Pattern'Length /= 0,
Global => null;
pragma Ada_05 (Index);
function Index
(Source : Unbounded_String;
Pattern : String;
From : Positive;
Going : Direction := Forward;
Mapping : Maps.Character_Mapping_Function) return Natural
with
Pre => (if Length (Source) /= 0 then From <= Length (Source))
and then Pattern'Length /= 0,
Global => null;
pragma Ada_05 (Index);
function Index
(Source : Unbounded_String;
Set : Maps.Character_Set;
From : Positive;
Test : Membership := Inside;
Going : Direction := Forward) return Natural
with
Pre => (if Length (Source) /= 0 then From <= Length (Source)),
Global => null;
pragma Ada_05 (Index);
function Index_Non_Blank
(Source : Unbounded_String;
Going : Direction := Forward) return Natural
with
Global => null;
function Index_Non_Blank
(Source : Unbounded_String;
From : Positive;
Going : Direction := Forward) return Natural
with
Pre => (if Length (Source) /= 0 then From <= Length (Source)),
Global => null;
pragma Ada_05 (Index_Non_Blank);
function Count
(Source : Unbounded_String;
Pattern : String;
Mapping : Maps.Character_Mapping := Maps.Identity) return Natural
with
Pre => Pattern'Length /= 0,
Global => null;
function Count
(Source : Unbounded_String;
Pattern : String;
Mapping : Maps.Character_Mapping_Function) return Natural
with
Pre => Pattern'Length /= 0,
Global => null;
function Count
(Source : Unbounded_String;
Set : Maps.Character_Set) return Natural
with
Global => null;
procedure Find_Token
(Source : Unbounded_String;
Set : Maps.Character_Set;
From : Positive;
Test : Membership;
First : out Positive;
Last : out Natural)
with
Pre => (if Length (Source) /= 0 then From <= Length (Source)),
Global => null;
pragma Ada_2012 (Find_Token);
procedure Find_Token
(Source : Unbounded_String;
Set : Maps.Character_Set;
Test : Membership;
First : out Positive;
Last : out Natural)
with
Global => null;
------------------------------------
-- String Translation Subprograms --
------------------------------------
function Translate
(Source : Unbounded_String;
Mapping : Maps.Character_Mapping) return Unbounded_String
with
Post => Length (Translate'Result) = Length (Source),
Global => null;
procedure Translate
(Source : in out Unbounded_String;
Mapping : Maps.Character_Mapping)
with
Post => Length (Source) = Length (Source)'Old,
Global => null;
function Translate
(Source : Unbounded_String;
Mapping : Maps.Character_Mapping_Function) return Unbounded_String
with
Post => Length (Translate'Result) = Length (Source),
Global => null;
procedure Translate
(Source : in out Unbounded_String;
Mapping : Maps.Character_Mapping_Function)
with
Post => Length (Source) = Length (Source)'Old,
Global => null;
---------------------------------------
-- String Transformation Subprograms --
---------------------------------------
function Replace_Slice
(Source : Unbounded_String;
Low : Positive;
High : Natural;
By : String) return Unbounded_String
with
Pre =>
Low - 1 <= Length (Source)
and then (if High >= Low
then Low - 1
<= Natural'Last - By'Length
- Natural'Max (Length (Source) - High, 0)
else Length (Source) <= Natural'Last - By'Length),
Contract_Cases =>
(High >= Low =>
Length (Replace_Slice'Result)
= Low - 1 + By'Length + Natural'Max (Length (Source)'Old - High, 0),
others =>
Length (Replace_Slice'Result) = Length (Source)'Old + By'Length),
Global => null;
procedure Replace_Slice
(Source : in out Unbounded_String;
Low : Positive;
High : Natural;
By : String)
with
Pre =>
Low - 1 <= Length (Source)
and then (if High >= Low
then Low - 1
<= Natural'Last - By'Length
- Natural'Max (Length (Source) - High, 0)
else Length (Source) <= Natural'Last - By'Length),
Contract_Cases =>
(High >= Low =>
Length (Source)
= Low - 1 + By'Length + Natural'Max (Length (Source)'Old - High, 0),
others =>
Length (Source) = Length (Source)'Old + By'Length),
Global => null;
function Insert
(Source : Unbounded_String;
Before : Positive;
New_Item : String) return Unbounded_String
with
Pre => Before - 1 <= Length (Source)
and then New_Item'Length <= Natural'Last - Length (Source),
Post => Length (Insert'Result) = Length (Source) + New_Item'Length,
Global => null;
procedure Insert
(Source : in out Unbounded_String;
Before : Positive;
New_Item : String)
with
Pre => Before - 1 <= Length (Source)
and then New_Item'Length <= Natural'Last - Length (Source),
Post => Length (Source) = Length (Source)'Old + New_Item'Length,
Global => null;
function Overwrite
(Source : Unbounded_String;
Position : Positive;
New_Item : String) return Unbounded_String
with
Pre => Position - 1 <= Length (Source)
and then (if New_Item'Length /= 0
then
New_Item'Length <= Natural'Last - (Position - 1)),
Post =>
Length (Overwrite'Result)
= Natural'Max (Length (Source), Position - 1 + New_Item'Length),
Global => null;
procedure Overwrite
(Source : in out Unbounded_String;
Position : Positive;
New_Item : String)
with
Pre => Position - 1 <= Length (Source)
and then (if New_Item'Length /= 0
then
New_Item'Length <= Natural'Last - (Position - 1)),
Post =>
Length (Source)
= Natural'Max (Length (Source)'Old, Position - 1 + New_Item'Length),
Global => null;
function Delete
(Source : Unbounded_String;
From : Positive;
Through : Natural) return Unbounded_String
with
Pre => (if Through <= From then From - 1 <= Length (Source)),
Contract_Cases =>
(Through >= From =>
Length (Delete'Result) = Length (Source) - (Through - From + 1),
others =>
Length (Delete'Result) = Length (Source)),
Global => null;
procedure Delete
(Source : in out Unbounded_String;
From : Positive;
Through : Natural)
with
Pre => (if Through <= From then From - 1 <= Length (Source)),
Contract_Cases =>
(Through >= From =>
Length (Source) = Length (Source)'Old - (Through - From + 1),
others =>
Length (Source) = Length (Source)'Old),
Global => null;
function Trim
(Source : Unbounded_String;
Side : Trim_End) return Unbounded_String
with
Post => Length (Trim'Result) <= Length (Source),
Global => null;
procedure Trim
(Source : in out Unbounded_String;
Side : Trim_End)
with
Post => Length (Source) <= Length (Source)'Old,
Global => null;
function Trim
(Source : Unbounded_String;
Left : Maps.Character_Set;
Right : Maps.Character_Set) return Unbounded_String
with
Post => Length (Trim'Result) <= Length (Source),
Global => null;
procedure Trim
(Source : in out Unbounded_String;
Left : Maps.Character_Set;
Right : Maps.Character_Set)
with
Post => Length (Source) <= Length (Source)'Old,
Global => null;
function Head
(Source : Unbounded_String;
Count : Natural;
Pad : Character := Space) return Unbounded_String
with
Post => Length (Head'Result) = Count,
Global => null;
procedure Head
(Source : in out Unbounded_String;
Count : Natural;
Pad : Character := Space)
with
Post => Length (Source) = Count,
Global => null;
function Tail
(Source : Unbounded_String;
Count : Natural;
Pad : Character := Space) return Unbounded_String
with
Post => Length (Tail'Result) = Count,
Global => null;
procedure Tail
(Source : in out Unbounded_String;
Count : Natural;
Pad : Character := Space)
with
Post => Length (Source) = Count,
Global => null;
function "*"
(Left : Natural;
Right : Character) return Unbounded_String
with
Pre => Left <= Natural'Last,
Post => Length ("*"'Result) = Left,
Global => null;
function "*"
(Left : Natural;
Right : String) return Unbounded_String
with
Pre => (if Left /= 0 then Right'Length <= Natural'Last / Left),
Post => Length ("*"'Result) = Left * Right'Length,
Global => null;
function "*"
(Left : Natural;
Right : Unbounded_String) return Unbounded_String
with
Pre => (if Left /= 0 then Length (Right) <= Natural'Last / Left),
Post => Length ("*"'Result) = Left * Length (Right),
Global => null;
private
pragma Inline (Length);
package AF renames Ada.Finalization;
type Shared_String (Max_Length : Natural) is limited record
Counter : System.Atomic_Counters.Atomic_Counter;
-- Reference counter
Last : Natural := 0;
Data : String (1 .. Max_Length);
-- Last is the index of last significant element of the Data. All
-- elements with larger indexes are currently insignificant.
end record;
type Shared_String_Access is access all Shared_String;
procedure Reference (Item : not null Shared_String_Access);
-- Increment reference counter.
-- Do nothing if Item points to Empty_Shared_String.
procedure Unreference (Item : not null Shared_String_Access);
-- Decrement reference counter, deallocate Item when counter goes to zero.
-- Do nothing if Item points to Empty_Shared_String.
function Can_Be_Reused
(Item : not null Shared_String_Access;
Length : Natural) return Boolean;
-- Returns True if Shared_String can be reused. There are two criteria when
-- Shared_String can be reused: its reference counter must be one (thus
-- Shared_String is owned exclusively) and its size is sufficient to
-- store string with specified length effectively.
function Allocate
(Required_Length : Natural;
Reserved_Length : Natural := 0) return not null Shared_String_Access;
-- Allocates new Shared_String. Actual maximum length of allocated object
-- is at least the specified required length. Additional storage is
-- allocated to allow to store up to the specified reserved length when
-- possible. Returns reference to Empty_Shared_String when requested length
-- is zero.
Empty_Shared_String : aliased Shared_String (0);
function To_Unbounded (S : String) return Unbounded_String
renames To_Unbounded_String;
-- This renames are here only to be used in the pragma Stream_Convert
type Unbounded_String is new AF.Controlled with record
Reference : not null Shared_String_Access := Empty_Shared_String'Access;
end record with Put_Image => Put_Image;
procedure Put_Image
(S : in out Ada.Strings.Text_Buffers.Root_Buffer_Type'Class;
V : Unbounded_String);
pragma Stream_Convert (Unbounded_String, To_Unbounded, To_String);
-- Provide stream routines without dragging in Ada.Streams
pragma Finalize_Storage_Only (Unbounded_String);
-- Finalization is required only for freeing storage
overriding procedure Initialize (Object : in out Unbounded_String);
overriding procedure Adjust (Object : in out Unbounded_String);
overriding procedure Finalize (Object : in out Unbounded_String);
pragma Inline (Initialize, Adjust);
Null_Unbounded_String : constant Unbounded_String :=
(AF.Controlled with
Reference => Empty_Shared_String'Access);
end Ada.Strings.Unbounded;