1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                     G N A T . A R R A Y _ S P L I T                      --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 2002-2013, 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--  Useful array-manipulation routines: given a set of separators, split
33--  an array wherever the separators appear, and provide direct access
34--  to the resulting slices.
35
36with Ada.Finalization;
37
38generic
39   type Element is (<>);
40   --  Element of the array, this must be a discrete type
41
42   type Element_Sequence is array (Positive range <>) of Element;
43   --  The array which is a sequence of element
44
45   type Element_Set is private;
46   --  This type represent a set of elements. This set does not defined a
47   --  specific order of the elements. The conversion of a sequence to a
48   --  set and membership tests in the set is performed using the routines
49   --  To_Set and Is_In defined below.
50
51   with function To_Set (Sequence : Element_Sequence) return Element_Set;
52   --  Returns an Element_Set given an Element_Sequence. Duplicate elements
53   --  can be ignored during this conversion.
54
55   with function Is_In (Item : Element; Set : Element_Set) return Boolean;
56   --  Returns True if Item is found in Set, False otherwise
57
58package GNAT.Array_Split is
59
60   Index_Error : exception;
61   --  Raised by all operations below if Index > Field_Count (S)
62
63   type Separator_Mode is
64     (Single,
65      --  In this mode the array is cut at each element in the separator
66      --  set. If two separators are contiguous the result at that position
67      --  is an empty slice.
68
69      Multiple
70      --  In this mode contiguous separators are handled as a single
71      --  separator and no empty slice is created.
72     );
73
74   type Slice_Set is private;
75   --  This type uses by-reference semantics. This is a set of slices as
76   --  returned by Create or Set routines below. The abstraction represents
77   --  a set of items. Each item is a part of the original string named a
78   --  Slice. It is possible to access individual slices by using the Slice
79   --  routine below. The first slice in the Set is at the position/index
80   --  1. The total number of slices in the set is returned by Slice_Count.
81
82   procedure Create
83     (S          : out Slice_Set;
84      From       : Element_Sequence;
85      Separators : Element_Sequence;
86      Mode       : Separator_Mode := Single);
87   --  Create a cut array object. From is the source array, and Separators
88   --  is a sequence of Element along which to split the array. The source
89   --  array is sliced at separator boundaries. The separators are not
90   --  included as part of the resulting slices.
91   --
92   --  Note that if From is terminated by a separator an extra empty element
93   --  is added to the slice set. If From only contains a separator the slice
94   --  set contains two empty elements.
95
96   procedure Create
97     (S          : out Slice_Set;
98      From       : Element_Sequence;
99      Separators : Element_Set;
100      Mode       : Separator_Mode := Single);
101   --  Same as above but using a Element_Set
102
103   procedure Set
104     (S          : in out Slice_Set;
105      Separators : Element_Sequence;
106      Mode       : Separator_Mode := Single);
107   --  Change the set of separators. The source array will be split according
108   --  to this new set of separators.
109
110   procedure Set
111     (S          : in out Slice_Set;
112      Separators : Element_Set;
113      Mode       : Separator_Mode := Single);
114   --  Same as above but using a Element_Set
115
116   type Slice_Number is new Natural;
117   --  Type used to count number of slices
118
119   function Slice_Count (S : Slice_Set) return Slice_Number;
120   pragma Inline (Slice_Count);
121   --  Returns the number of slices (fields) in S
122
123   function Slice
124     (S     : Slice_Set;
125      Index : Slice_Number) return Element_Sequence;
126   pragma Inline (Slice);
127   --  Returns the slice at position Index. First slice is 1. If Index is 0
128   --  the whole array is returned including the separators (this is the
129   --  original source array).
130
131   type Position is (Before, After);
132   --  Used to designate position of separator
133
134   type Slice_Separators is array (Position) of Element;
135   --  Separators found before and after the slice
136
137   Array_End : constant Element;
138   --  This is the separator returned for the start or the end of the array
139
140   function Separators
141     (S     : Slice_Set;
142      Index : Slice_Number) return Slice_Separators;
143   --  Returns the separators used to slice (front and back) the slice at
144   --  position Index. For slices at start and end of the original array, the
145   --  Array_End value is returned for the corresponding outer bound. In
146   --  Multiple mode only the element closest to the slice is returned.
147   --  if Index = 0, returns (Array_End, Array_End).
148
149   type Separators_Indexes is array (Positive range <>) of Positive;
150
151   function Separators (S : Slice_Set) return Separators_Indexes;
152   --  Returns indexes of all separators used to slice original source array S
153
154private
155
156   Array_End : constant Element := Element'First;
157
158   type Element_Access is access Element_Sequence;
159
160   type Indexes_Access is access Separators_Indexes;
161
162   type Slice_Info is record
163      Start : Positive;
164      Stop  : Natural;
165   end record;
166   --  Starting/Ending position of a slice. This does not include separators
167
168   type Slices_Indexes is array (Slice_Number range <>) of Slice_Info;
169   type Slices_Access is access Slices_Indexes;
170   --  All indexes for fast access to slices. In the Slice_Set we keep only
171   --  the original array and the indexes where each slice start and stop.
172
173   type Data is record
174      Ref_Counter : Natural;            -- Reference counter, by-address sem
175      Source      : Element_Access;
176      N_Slice     : Slice_Number := 0;  -- Number of slices found
177      Indexes     : Indexes_Access;
178      Slices      : Slices_Access;
179   end record;
180   type Data_Access is access all Data;
181
182   type Slice_Set is new Ada.Finalization.Controlled with record
183      D : Data_Access;
184   end record;
185
186   procedure Initialize (S : in out Slice_Set);
187   procedure Adjust     (S : in out Slice_Set);
188   procedure Finalize   (S : in out Slice_Set);
189
190end GNAT.Array_Split;
191