1------------------------------------------------------------------------------ 2-- -- 3-- GNAT LIBRARY COMPONENTS -- 4-- -- 5-- A D A . C O N T A I N E R S . H A S H E D _ M A P S -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 2004-2015, 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.Finalization; 38private with Ada.Streams; 39 40generic 41 type Key_Type is private; 42 type Element_Type is private; 43 44 with function Hash (Key : Key_Type) return Hash_Type; 45 with function Equivalent_Keys (Left, Right : Key_Type) return Boolean; 46 with function "=" (Left, Right : Element_Type) return Boolean is <>; 47 48package Ada.Containers.Hashed_Maps is 49 pragma Annotate (CodePeer, Skip_Analysis); 50 pragma Preelaborate; 51 pragma Remote_Types; 52 53 type Map is tagged private 54 with 55 Constant_Indexing => Constant_Reference, 56 Variable_Indexing => Reference, 57 Default_Iterator => Iterate, 58 Iterator_Element => Element_Type; 59 60 pragma Preelaborable_Initialization (Map); 61 62 type Cursor is private; 63 pragma Preelaborable_Initialization (Cursor); 64 65 Empty_Map : constant Map; 66 -- Map objects declared without an initialization expression are 67 -- initialized to the value Empty_Map. 68 69 No_Element : constant Cursor; 70 -- Cursor objects declared without an initialization expression are 71 -- initialized to the value No_Element. 72 73 function Has_Element (Position : Cursor) return Boolean; 74 -- Equivalent to Position /= No_Element 75 76 package Map_Iterator_Interfaces is new 77 Ada.Iterator_Interfaces (Cursor, Has_Element); 78 79 function "=" (Left, Right : Map) return Boolean; 80 -- For each key/element pair in Left, equality attempts to find the key in 81 -- Right; if a search fails the equality returns False. The search works by 82 -- calling Hash to find the bucket in the Right map that corresponds to the 83 -- Left key. If bucket is non-empty, then equality calls Equivalent_Keys 84 -- to compare the key (in Left) to the key of each node in the bucket (in 85 -- Right); if the keys are equivalent, then the equality test for this 86 -- key/element pair (in Left) completes by calling the element equality 87 -- operator to compare the element (in Left) to the element of the node 88 -- (in Right) whose key matched. 89 90 function Capacity (Container : Map) return Count_Type; 91 -- Returns the current capacity of the map. Capacity is the maximum length 92 -- before which rehashing in guaranteed not to occur. 93 94 procedure Reserve_Capacity (Container : in out Map; Capacity : Count_Type); 95 -- Adjusts the current capacity, by allocating a new buckets array. If the 96 -- requested capacity is less than the current capacity, then the capacity 97 -- is contracted (to a value not less than the current length). If the 98 -- requested capacity is greater than the current capacity, then the 99 -- capacity is expanded (to a value not less than what is requested). In 100 -- either case, the nodes are rehashed from the old buckets array onto the 101 -- new buckets array (Hash is called once for each existing key in order to 102 -- compute the new index), and then the old buckets array is deallocated. 103 104 function Length (Container : Map) return Count_Type; 105 -- Returns the number of items in the map 106 107 function Is_Empty (Container : Map) return Boolean; 108 -- Equivalent to Length (Container) = 0 109 110 procedure Clear (Container : in out Map); 111 -- Removes all of the items from the map 112 113 function Key (Position : Cursor) return Key_Type; 114 -- Returns the key of the node designated by the cursor 115 116 function Element (Position : Cursor) return Element_Type; 117 -- Returns the element of the node designated by the cursor 118 119 procedure Replace_Element 120 (Container : in out Map; 121 Position : Cursor; 122 New_Item : Element_Type); 123 -- Assigns the value New_Item to the element designated by the cursor 124 125 procedure Query_Element 126 (Position : Cursor; 127 Process : not null access 128 procedure (Key : Key_Type; Element : Element_Type)); 129 -- Calls Process with the key and element (both having only a constant 130 -- view) of the node designed by the cursor. 131 132 procedure Update_Element 133 (Container : in out Map; 134 Position : Cursor; 135 Process : not null access 136 procedure (Key : Key_Type; Element : in out Element_Type)); 137 -- Calls Process with the key (with only a constant view) and element (with 138 -- a variable view) of the node designed by the cursor. 139 140 type Constant_Reference_Type 141 (Element : not null access constant Element_Type) is private 142 with 143 Implicit_Dereference => Element; 144 145 type Reference_Type (Element : not null access Element_Type) is private 146 with 147 Implicit_Dereference => Element; 148 149 function Constant_Reference 150 (Container : aliased Map; 151 Position : Cursor) return Constant_Reference_Type; 152 pragma Inline (Constant_Reference); 153 154 function Reference 155 (Container : aliased in out Map; 156 Position : Cursor) return Reference_Type; 157 pragma Inline (Reference); 158 159 function Constant_Reference 160 (Container : aliased Map; 161 Key : Key_Type) return Constant_Reference_Type; 162 pragma Inline (Constant_Reference); 163 164 function Reference 165 (Container : aliased in out Map; 166 Key : Key_Type) return Reference_Type; 167 pragma Inline (Reference); 168 169 procedure Assign (Target : in out Map; Source : Map); 170 171 function Copy (Source : Map; Capacity : Count_Type := 0) return Map; 172 173 procedure Move (Target : in out Map; Source : in out Map); 174 -- Clears Target (if it's not empty), and then moves (not copies) the 175 -- buckets array and nodes from Source to Target. 176 177 procedure Insert 178 (Container : in out Map; 179 Key : Key_Type; 180 New_Item : Element_Type; 181 Position : out Cursor; 182 Inserted : out Boolean); 183 -- Conditionally inserts New_Item into the map. If Key is already in the 184 -- map, then Inserted returns False and Position designates the node 185 -- containing the existing key/element pair (neither of which is modified). 186 -- If Key is not already in the map, the Inserted returns True and Position 187 -- designates the newly-inserted node container Key and New_Item. The 188 -- search for the key works as follows. Hash is called to determine Key's 189 -- bucket; if the bucket is non-empty, then Equivalent_Keys is called to 190 -- compare Key to each node in that bucket. If the bucket is empty, or 191 -- there were no matching keys in the bucket, the search "fails" and the 192 -- key/item pair is inserted in the map (and Inserted returns True); 193 -- otherwise, the search "succeeds" (and Inserted returns False). 194 195 procedure Insert 196 (Container : in out Map; 197 Key : Key_Type; 198 Position : out Cursor; 199 Inserted : out Boolean); 200 -- The same as the (conditional) Insert that accepts an element parameter, 201 -- with the difference that if Inserted returns True, then the element of 202 -- the newly-inserted node is initialized to its default value. 203 204 procedure Insert 205 (Container : in out Map; 206 Key : Key_Type; 207 New_Item : Element_Type); 208 -- Attempts to insert Key into the map, performing the usual search (which 209 -- involves calling both Hash and Equivalent_Keys); if the search succeeds 210 -- (because Key is already in the map), then it raises Constraint_Error. 211 -- (This version of Insert is similar to Replace, but having the opposite 212 -- exception behavior. It is intended for use when you want to assert that 213 -- Key is not already in the map.) 214 215 procedure Include 216 (Container : in out Map; 217 Key : Key_Type; 218 New_Item : Element_Type); 219 -- Attempts to insert Key into the map. If Key is already in the map, then 220 -- both the existing key and element are assigned the values of Key and 221 -- New_Item, respectively. (This version of Insert only raises an exception 222 -- if cursor tampering occurs. It is intended for use when you want to 223 -- insert the key/element pair in the map, and you don't care whether Key 224 -- is already present.) 225 226 procedure Replace 227 (Container : in out Map; 228 Key : Key_Type; 229 New_Item : Element_Type); 230 -- Searches for Key in the map; if the search fails (because Key was not in 231 -- the map), then it raises Constraint_Error. Otherwise, both the existing 232 -- key and element are assigned the values of Key and New_Item rsp. (This 233 -- is similar to Insert, but with the opposite exception behavior. It is to 234 -- be used when you want to assert that Key is already in the map.) 235 236 procedure Exclude (Container : in out Map; Key : Key_Type); 237 -- Searches for Key in the map, and if found, removes its node from the map 238 -- and then deallocates it. The search works as follows. The operation 239 -- calls Hash to determine the key's bucket; if the bucket is not empty, it 240 -- calls Equivalent_Keys to compare Key to each key in the bucket. (This is 241 -- the deletion analog of Include. It is intended for use when you want to 242 -- remove the item from the map, but don't care whether the key is already 243 -- in the map.) 244 245 procedure Delete (Container : in out Map; Key : Key_Type); 246 -- Searches for Key in the map (which involves calling both Hash and 247 -- Equivalent_Keys). If the search fails, then the operation raises 248 -- Constraint_Error. Otherwise it removes the node from the map and then 249 -- deallocates it. (This is the deletion analog of non-conditional 250 -- Insert. It is intended for use when you want to assert that the item is 251 -- already in the map.) 252 253 procedure Delete (Container : in out Map; Position : in out Cursor); 254 -- Removes the node designated by Position from the map, and then 255 -- deallocates the node. The operation calls Hash to determine the bucket, 256 -- and then compares Position to each node in the bucket until there's a 257 -- match (it does not call Equivalent_Keys). 258 259 function First (Container : Map) return Cursor; 260 -- Returns a cursor that designates the first non-empty bucket, by 261 -- searching from the beginning of the buckets array. 262 263 function Next (Position : Cursor) return Cursor; 264 -- Returns a cursor that designates the node that follows the current one 265 -- designated by Position. If Position designates the last node in its 266 -- bucket, the operation calls Hash to compute the index of this bucket, 267 -- and searches the buckets array for the first non-empty bucket, starting 268 -- from that index; otherwise, it simply follows the link to the next node 269 -- in the same bucket. 270 271 procedure Next (Position : in out Cursor); 272 -- Equivalent to Position := Next (Position) 273 274 function Find (Container : Map; Key : Key_Type) return Cursor; 275 -- Searches for Key in the map. Find calls Hash to determine the key's 276 -- bucket; if the bucket is not empty, it calls Equivalent_Keys to compare 277 -- Key to each key in the bucket. If the search succeeds, Find returns a 278 -- cursor designating the matching node; otherwise, it returns No_Element. 279 280 function Contains (Container : Map; Key : Key_Type) return Boolean; 281 -- Equivalent to Find (Container, Key) /= No_Element 282 283 function Element (Container : Map; Key : Key_Type) return Element_Type; 284 -- Equivalent to Element (Find (Container, Key)) 285 286 function Equivalent_Keys (Left, Right : Cursor) return Boolean; 287 -- Returns the result of calling Equivalent_Keys with the keys of the nodes 288 -- designated by cursors Left and Right. 289 290 function Equivalent_Keys (Left : Cursor; Right : Key_Type) return Boolean; 291 -- Returns the result of calling Equivalent_Keys with key of the node 292 -- designated by Left and key Right. 293 294 function Equivalent_Keys (Left : Key_Type; Right : Cursor) return Boolean; 295 -- Returns the result of calling Equivalent_Keys with key Left and the node 296 -- designated by Right. 297 298 procedure Iterate 299 (Container : Map; 300 Process : not null access procedure (Position : Cursor)); 301 -- Calls Process for each node in the map 302 303 function Iterate 304 (Container : Map) return Map_Iterator_Interfaces.Forward_Iterator'Class; 305 306private 307 pragma Inline ("="); 308 pragma Inline (Length); 309 pragma Inline (Is_Empty); 310 pragma Inline (Clear); 311 pragma Inline (Key); 312 pragma Inline (Element); 313 pragma Inline (Move); 314 pragma Inline (Contains); 315 pragma Inline (Capacity); 316 pragma Inline (Reserve_Capacity); 317 pragma Inline (Has_Element); 318 pragma Inline (Equivalent_Keys); 319 pragma Inline (Next); 320 321 type Node_Type; 322 type Node_Access is access Node_Type; 323 324 type Node_Type is limited record 325 Key : Key_Type; 326 Element : aliased Element_Type; 327 Next : Node_Access; 328 end record; 329 330 package HT_Types is 331 new Hash_Tables.Generic_Hash_Table_Types (Node_Type, Node_Access); 332 333 type Map is new Ada.Finalization.Controlled with record 334 HT : HT_Types.Hash_Table_Type; 335 end record; 336 337 overriding procedure Adjust (Container : in out Map); 338 339 overriding procedure Finalize (Container : in out Map); 340 341 use HT_Types, HT_Types.Implementation; 342 use Ada.Finalization; 343 use Ada.Streams; 344 345 procedure Write 346 (Stream : not null access Root_Stream_Type'Class; 347 Container : Map); 348 349 for Map'Write use Write; 350 351 procedure Read 352 (Stream : not null access Root_Stream_Type'Class; 353 Container : out Map); 354 355 for Map'Read use Read; 356 357 type Map_Access is access all Map; 358 for Map_Access'Storage_Size use 0; 359 360 type Cursor is record 361 Container : Map_Access; 362 Node : Node_Access; 363 end record; 364 365 procedure Read 366 (Stream : not null access Root_Stream_Type'Class; 367 Item : out Cursor); 368 369 for Cursor'Read use Read; 370 371 procedure Write 372 (Stream : not null access Root_Stream_Type'Class; 373 Item : Cursor); 374 375 for Cursor'Write use Write; 376 377 subtype Reference_Control_Type is Implementation.Reference_Control_Type; 378 -- It is necessary to rename this here, so that the compiler can find it 379 380 type Constant_Reference_Type 381 (Element : not null access constant Element_Type) is 382 record 383 Control : Reference_Control_Type := 384 raise Program_Error with "uninitialized reference"; 385 -- The RM says, "The default initialization of an object of 386 -- type Constant_Reference_Type or Reference_Type propagates 387 -- Program_Error." 388 end record; 389 390 procedure Write 391 (Stream : not null access Root_Stream_Type'Class; 392 Item : Constant_Reference_Type); 393 394 for Constant_Reference_Type'Write use Write; 395 396 procedure Read 397 (Stream : not null access Root_Stream_Type'Class; 398 Item : out Constant_Reference_Type); 399 400 for Constant_Reference_Type'Read use Read; 401 402 type Reference_Type 403 (Element : not null access Element_Type) is 404 record 405 Control : Reference_Control_Type := 406 raise Program_Error with "uninitialized reference"; 407 -- The RM says, "The default initialization of an object of 408 -- type Constant_Reference_Type or Reference_Type propagates 409 -- Program_Error." 410 end record; 411 412 procedure Write 413 (Stream : not null access Root_Stream_Type'Class; 414 Item : Reference_Type); 415 416 for Reference_Type'Write use Write; 417 418 procedure Read 419 (Stream : not null access Root_Stream_Type'Class; 420 Item : out Reference_Type); 421 422 for Reference_Type'Read use Read; 423 424 -- Three operations are used to optimize in the expansion of "for ... of" 425 -- loops: the Next(Cursor) procedure in the visible part, and the following 426 -- Pseudo_Reference and Get_Element_Access functions. See Sem_Ch5 for 427 -- details. 428 429 function Pseudo_Reference 430 (Container : aliased Map'Class) return Reference_Control_Type; 431 pragma Inline (Pseudo_Reference); 432 -- Creates an object of type Reference_Control_Type pointing to the 433 -- container, and increments the Lock. Finalization of this object will 434 -- decrement the Lock. 435 436 type Element_Access is access all Element_Type with 437 Storage_Size => 0; 438 439 function Get_Element_Access 440 (Position : Cursor) return not null Element_Access; 441 -- Returns a pointer to the element designated by Position. 442 443 Empty_Map : constant Map := (Controlled with others => <>); 444 445 No_Element : constant Cursor := (Container => null, Node => null); 446 447 type Iterator is new Limited_Controlled and 448 Map_Iterator_Interfaces.Forward_Iterator with 449 record 450 Container : Map_Access; 451 end record 452 with Disable_Controlled => not T_Check; 453 454 overriding procedure Finalize (Object : in out Iterator); 455 456 overriding function First (Object : Iterator) return Cursor; 457 458 overriding function Next 459 (Object : Iterator; 460 Position : Cursor) return Cursor; 461 462end Ada.Containers.Hashed_Maps; 463