1------------------------------------------------------------------------------ 2-- -- 3-- GNAT LIBRARY COMPONENTS -- 4-- -- 5-- A D A . C O N T A I N E R S . B O U N D E D _ H A S H E D _ M A P S -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 2004-2012, Free Software Foundation, Inc. -- 10-- -- 11-- This specification is derived from the Ada Reference Manual for use with -- 12-- GNAT. The copyright notice above, and the license provisions that follow -- 13-- apply solely to the contents of the part following the private keyword. -- 14-- -- 15-- GNAT is free software; you can redistribute it and/or modify it under -- 16-- terms of the GNU General Public License as published by the Free Soft- -- 17-- ware Foundation; either version 3, or (at your option) any later ver- -- 18-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 19-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 20-- or FITNESS FOR A PARTICULAR PURPOSE. -- 21-- -- 22-- As a special exception under Section 7 of GPL version 3, you are granted -- 23-- additional permissions described in the GCC Runtime Library Exception, -- 24-- version 3.1, as published by the Free Software Foundation. -- 25-- -- 26-- You should have received a copy of the GNU General Public License and -- 27-- a copy of the GCC Runtime Library Exception along with this program; -- 28-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 29-- <http://www.gnu.org/licenses/>. -- 30-- -- 31-- This unit was originally developed by Matthew J Heaney. -- 32------------------------------------------------------------------------------ 33 34with Ada.Iterator_Interfaces; 35 36private with Ada.Containers.Hash_Tables; 37private with Ada.Streams; 38 39generic 40 type Key_Type is private; 41 type Element_Type is private; 42 43 with function Hash (Key : Key_Type) return Hash_Type; 44 with function Equivalent_Keys (Left, Right : Key_Type) return Boolean; 45 with function "=" (Left, Right : Element_Type) return Boolean is <>; 46 47package Ada.Containers.Bounded_Hashed_Maps is 48 pragma Pure; 49 pragma Remote_Types; 50 51 type Map (Capacity : Count_Type; Modulus : Hash_Type) is tagged private with 52 Constant_Indexing => Constant_Reference, 53 Variable_Indexing => Reference, 54 Default_Iterator => Iterate, 55 Iterator_Element => Element_Type; 56 57 pragma Preelaborable_Initialization (Map); 58 59 type Cursor is private; 60 pragma Preelaborable_Initialization (Cursor); 61 62 Empty_Map : constant Map; 63 -- Map objects declared without an initialization expression are 64 -- initialized to the value Empty_Map. 65 66 No_Element : constant Cursor; 67 -- Cursor objects declared without an initialization expression are 68 -- initialized to the value No_Element. 69 70 function Has_Element (Position : Cursor) return Boolean; 71 -- Equivalent to Position /= No_Element 72 73 package Map_Iterator_Interfaces is new 74 Ada.Iterator_Interfaces (Cursor, Has_Element); 75 76 function "=" (Left, Right : Map) return Boolean; 77 -- For each key/element pair in Left, equality attempts to find the key in 78 -- Right; if a search fails the equality returns False. The search works by 79 -- calling Hash to find the bucket in the Right map that corresponds to the 80 -- Left key. If bucket is non-empty, then equality calls Equivalent_Keys 81 -- to compare the key (in Left) to the key of each node in the bucket (in 82 -- Right); if the keys are equivalent, then the equality test for this 83 -- key/element pair (in Left) completes by calling the element equality 84 -- operator to compare the element (in Left) to the element of the node 85 -- (in Right) whose key matched. 86 87 function Capacity (Container : Map) return Count_Type; 88 -- Returns the current capacity of the map. Capacity is the maximum length 89 -- before which rehashing in guaranteed not to occur. 90 91 procedure Reserve_Capacity (Container : in out Map; Capacity : Count_Type); 92 -- If the value of the Capacity actual parameter is less or equal to 93 -- Container.Capacity, then the operation has no effect. Otherwise it 94 -- raises Capacity_Error (as no expansion of capacity is possible for a 95 -- bounded form). 96 97 function Default_Modulus (Capacity : Count_Type) return Hash_Type; 98 -- Returns a modulus value (hash table size) which is optimal for the 99 -- specified capacity (which corresponds to the maximum number of items). 100 101 function Length (Container : Map) return Count_Type; 102 -- Returns the number of items in the map 103 104 function Is_Empty (Container : Map) return Boolean; 105 -- Equivalent to Length (Container) = 0 106 107 procedure Clear (Container : in out Map); 108 -- Removes all of the items from the map 109 110 function Key (Position : Cursor) return Key_Type; 111 -- Returns the key of the node designated by the cursor 112 113 function Element (Position : Cursor) return Element_Type; 114 -- Returns the element of the node designated by the cursor 115 116 procedure Replace_Element 117 (Container : in out Map; 118 Position : Cursor; 119 New_Item : Element_Type); 120 -- Assigns the value New_Item to the element designated by the cursor 121 122 procedure Query_Element 123 (Position : Cursor; 124 Process : not null access 125 procedure (Key : Key_Type; Element : Element_Type)); 126 -- Calls Process with the key and element (both having only a constant 127 -- view) of the node designed by the cursor. 128 129 procedure Update_Element 130 (Container : in out Map; 131 Position : Cursor; 132 Process : not null access 133 procedure (Key : Key_Type; Element : in out Element_Type)); 134 -- Calls Process with the key (with only a constant view) and element (with 135 -- a variable view) of the node designed by the cursor. 136 137 type Constant_Reference_Type 138 (Element : not null access constant Element_Type) is 139 private 140 with 141 Implicit_Dereference => Element; 142 143 type Reference_Type (Element : not null access Element_Type) is private 144 with 145 Implicit_Dereference => Element; 146 147 function Constant_Reference 148 (Container : aliased Map; 149 Position : Cursor) return Constant_Reference_Type; 150 151 function Reference 152 (Container : aliased in out Map; 153 Position : Cursor) return Reference_Type; 154 155 function Constant_Reference 156 (Container : aliased Map; 157 Key : Key_Type) return Constant_Reference_Type; 158 159 function Reference 160 (Container : aliased in out Map; 161 Key : Key_Type) return Reference_Type; 162 163 procedure Assign (Target : in out Map; Source : Map); 164 -- If Target denotes the same object as Source, then the operation has no 165 -- effect. If the Target capacity is less than the Source length, then 166 -- Assign raises Capacity_Error. Otherwise, Assign clears Target and then 167 -- copies the (active) elements from Source to Target. 168 169 function Copy 170 (Source : Map; 171 Capacity : Count_Type := 0; 172 Modulus : Hash_Type := 0) return Map; 173 -- Constructs a new set object whose elements correspond to Source. If the 174 -- Capacity parameter is 0, then the capacity of the result is the same as 175 -- the length of Source. If the Capacity parameter is equal or greater than 176 -- the length of Source, then the capacity of the result is the specified 177 -- value. Otherwise, Copy raises Capacity_Error. If the Modulus parameter 178 -- is 0, then the modulus of the result is the value returned by a call to 179 -- Default_Modulus with the capacity parameter determined as above; 180 -- otherwise the modulus of the result is the specified value. 181 182 procedure Move (Target : in out Map; Source : in out Map); 183 -- Clears Target (if it's not empty), and then moves (not copies) the 184 -- buckets array and nodes from Source to Target. 185 186 procedure Insert 187 (Container : in out Map; 188 Key : Key_Type; 189 New_Item : Element_Type; 190 Position : out Cursor; 191 Inserted : out Boolean); 192 -- Conditionally inserts New_Item into the map. If Key is already in the 193 -- map, then Inserted returns False and Position designates the node 194 -- containing the existing key/element pair (neither of which is modified). 195 -- If Key is not already in the map, the Inserted returns True and Position 196 -- designates the newly-inserted node container Key and New_Item. The 197 -- search for the key works as follows. Hash is called to determine Key's 198 -- bucket; if the bucket is non-empty, then Equivalent_Keys is called to 199 -- compare Key to each node in that bucket. If the bucket is empty, or 200 -- there were no matching keys in the bucket, the search "fails" and the 201 -- key/item pair is inserted in the map (and Inserted returns True); 202 -- otherwise, the search "succeeds" (and Inserted returns False). 203 204 procedure Insert 205 (Container : in out Map; 206 Key : Key_Type; 207 Position : out Cursor; 208 Inserted : out Boolean); 209 -- The same as the (conditional) Insert that accepts an element parameter, 210 -- with the difference that if Inserted returns True, then the element of 211 -- the newly-inserted node is initialized to its default value. 212 213 procedure Insert 214 (Container : in out Map; 215 Key : Key_Type; 216 New_Item : Element_Type); 217 -- Attempts to insert Key into the map, performing the usual search (which 218 -- involves calling both Hash and Equivalent_Keys); if the search succeeds 219 -- (because Key is already in the map), then it raises Constraint_Error. 220 -- (This version of Insert is similar to Replace, but having the opposite 221 -- exception behavior. It is intended for use when you want to assert that 222 -- Key is not already in the map.) 223 224 procedure Include 225 (Container : in out Map; 226 Key : Key_Type; 227 New_Item : Element_Type); 228 -- Attempts to insert Key into the map. If Key is already in the map, then 229 -- both the existing key and element are assigned the values of Key and 230 -- New_Item, respectively. (This version of Insert only raises an exception 231 -- if cursor tampering occurs. It is intended for use when you want to 232 -- insert the key/element pair in the map, and you don't care whether Key 233 -- is already present.) 234 235 procedure Replace 236 (Container : in out Map; 237 Key : Key_Type; 238 New_Item : Element_Type); 239 -- Searches for Key in the map; if the search fails (because Key was not in 240 -- the map), then it raises Constraint_Error. Otherwise, both the existing 241 -- key and element are assigned the values of Key and New_Item rsp. (This 242 -- is similar to Insert, but with the opposite exception behavior. It is to 243 -- be used when you want to assert that Key is already in the map.) 244 245 procedure Exclude (Container : in out Map; Key : Key_Type); 246 -- Searches for Key in the map, and if found, removes its node from the map 247 -- and then deallocates it. The search works as follows. The operation 248 -- calls Hash to determine the key's bucket; if the bucket is not empty, it 249 -- calls Equivalent_Keys to compare Key to each key in the bucket. (This is 250 -- the deletion analog of Include. It is intended for use when you want to 251 -- remove the item from the map, but don't care whether the key is already 252 -- in the map.) 253 254 procedure Delete (Container : in out Map; Key : Key_Type); 255 -- Searches for Key in the map (which involves calling both Hash and 256 -- Equivalent_Keys). If the search fails, then the operation raises 257 -- Constraint_Error. Otherwise it removes the node from the map and then 258 -- deallocates it. (This is the deletion analog of non-conditional 259 -- Insert. It is intended for use when you want to assert that the item is 260 -- already in the map.) 261 262 procedure Delete (Container : in out Map; Position : in out Cursor); 263 -- Removes the node designated by Position from the map, and then 264 -- deallocates the node. The operation calls Hash to determine the bucket, 265 -- and then compares Position to each node in the bucket until there's a 266 -- match (it does not call Equivalent_Keys). 267 268 function First (Container : Map) return Cursor; 269 -- Returns a cursor that designates the first non-empty bucket, by 270 -- searching from the beginning of the buckets array. 271 272 function Next (Position : Cursor) return Cursor; 273 -- Returns a cursor that designates the node that follows the current one 274 -- designated by Position. If Position designates the last node in its 275 -- bucket, the operation calls Hash to compute the index of this bucket, 276 -- and searches the buckets array for the first non-empty bucket, starting 277 -- from that index; otherwise, it simply follows the link to the next node 278 -- in the same bucket. 279 280 procedure Next (Position : in out Cursor); 281 -- Equivalent to Position := Next (Position) 282 283 function Find (Container : Map; Key : Key_Type) return Cursor; 284 -- Searches for Key in the map. Find calls Hash to determine the key's 285 -- bucket; if the bucket is not empty, it calls Equivalent_Keys to compare 286 -- Key to each key in the bucket. If the search succeeds, Find returns a 287 -- cursor designating the matching node; otherwise, it returns No_Element. 288 289 function Contains (Container : Map; Key : Key_Type) return Boolean; 290 -- Equivalent to Find (Container, Key) /= No_Element 291 292 function Element (Container : Map; Key : Key_Type) return Element_Type; 293 -- Equivalent to Element (Find (Container, Key)) 294 295 function Equivalent_Keys (Left, Right : Cursor) return Boolean; 296 -- Returns the result of calling Equivalent_Keys with the keys of the nodes 297 -- designated by cursors Left and Right. 298 299 function Equivalent_Keys (Left : Cursor; Right : Key_Type) return Boolean; 300 -- Returns the result of calling Equivalent_Keys with key of the node 301 -- designated by Left and key Right. 302 303 function Equivalent_Keys (Left : Key_Type; Right : Cursor) return Boolean; 304 -- Returns the result of calling Equivalent_Keys with key Left and the node 305 -- designated by Right. 306 307 procedure Iterate 308 (Container : Map; 309 Process : not null access procedure (Position : Cursor)); 310 -- Calls Process for each node in the map 311 312 function Iterate (Container : Map) 313 return Map_Iterator_Interfaces.Forward_Iterator'class; 314 315private 316 pragma Inline (Length); 317 pragma Inline (Is_Empty); 318 pragma Inline (Clear); 319 pragma Inline (Key); 320 pragma Inline (Element); 321 pragma Inline (Move); 322 pragma Inline (Contains); 323 pragma Inline (Capacity); 324 pragma Inline (Reserve_Capacity); 325 pragma Inline (Has_Element); 326 pragma Inline (Next); 327 328 type Node_Type is record 329 Key : Key_Type; 330 Element : aliased Element_Type; 331 Next : Count_Type; 332 end record; 333 334 package HT_Types is 335 new Hash_Tables.Generic_Bounded_Hash_Table_Types (Node_Type); 336 337 type Map (Capacity : Count_Type; Modulus : Hash_Type) is 338 new HT_Types.Hash_Table_Type (Capacity, Modulus) with null record; 339 340 use HT_Types; 341 use Ada.Streams; 342 343 procedure Write 344 (Stream : not null access Root_Stream_Type'Class; 345 Container : Map); 346 347 for Map'Write use Write; 348 349 procedure Read 350 (Stream : not null access Root_Stream_Type'Class; 351 Container : out Map); 352 353 for Map'Read use Read; 354 355 type Map_Access is access all Map; 356 for Map_Access'Storage_Size use 0; 357 358 -- Note: If a Cursor object has no explicit initialization expression, 359 -- it must default initialize to the same value as constant No_Element. 360 -- The Node component of type Cursor has scalar type Count_Type, so it 361 -- requires an explicit initialization expression of its own declaration, 362 -- in order for objects of record type Cursor to properly initialize. 363 364 type Cursor is record 365 Container : Map_Access; 366 Node : Count_Type := 0; 367 end record; 368 369 procedure Read 370 (Stream : not null access Root_Stream_Type'Class; 371 Item : out Cursor); 372 373 for Cursor'Read use Read; 374 375 procedure Write 376 (Stream : not null access Root_Stream_Type'Class; 377 Item : Cursor); 378 379 for Cursor'Write use Write; 380 381 type Constant_Reference_Type 382 (Element : not null access constant Element_Type) is null record; 383 384 procedure Write 385 (Stream : not null access Root_Stream_Type'Class; 386 Item : Constant_Reference_Type); 387 388 for Constant_Reference_Type'Write use Write; 389 390 procedure Read 391 (Stream : not null access Root_Stream_Type'Class; 392 Item : out Constant_Reference_Type); 393 394 for Constant_Reference_Type'Read use Read; 395 396 type Reference_Type 397 (Element : not null access Element_Type) is null record; 398 399 procedure Write 400 (Stream : not null access Root_Stream_Type'Class; 401 Item : Reference_Type); 402 403 for Reference_Type'Write use Write; 404 405 procedure Read 406 (Stream : not null access Root_Stream_Type'Class; 407 Item : out Reference_Type); 408 409 for Reference_Type'Read use Read; 410 411 Empty_Map : constant Map := 412 (Hash_Table_Type with Capacity => 0, Modulus => 0); 413 414 No_Element : constant Cursor := (Container => null, Node => 0); 415 416end Ada.Containers.Bounded_Hashed_Maps; 417