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) 2004-2019, 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; 38private with Ada.Finalization; 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.Bounded_Hashed_Maps is 49 pragma Annotate (CodePeer, Skip_Analysis); 50 pragma Pure; 51 pragma Remote_Types; 52 53 type Map (Capacity : Count_Type; Modulus : Hash_Type) is tagged private with 54 Constant_Indexing => Constant_Reference, 55 Variable_Indexing => Reference, 56 Default_Iterator => Iterate, 57 Iterator_Element => Element_Type; 58 59 pragma Preelaborable_Initialization (Map); 60 61 type Cursor is private; 62 pragma Preelaborable_Initialization (Cursor); 63 64 Empty_Map : constant Map; 65 -- Map objects declared without an initialization expression are 66 -- initialized to the value Empty_Map. 67 68 No_Element : constant Cursor; 69 -- Cursor objects declared without an initialization expression are 70 -- initialized to the value No_Element. 71 72 function Has_Element (Position : Cursor) return Boolean; 73 -- Equivalent to Position /= No_Element 74 75 package Map_Iterator_Interfaces is new 76 Ada.Iterator_Interfaces (Cursor, Has_Element); 77 78 function "=" (Left, Right : Map) return Boolean; 79 -- For each key/element pair in Left, equality attempts to find the key in 80 -- Right; if a search fails the equality returns False. The search works by 81 -- calling Hash to find the bucket in the Right map that corresponds to the 82 -- Left key. If bucket is non-empty, then equality calls Equivalent_Keys 83 -- to compare the key (in Left) to the key of each node in the bucket (in 84 -- Right); if the keys are equivalent, then the equality test for this 85 -- key/element pair (in Left) completes by calling the element equality 86 -- operator to compare the element (in Left) to the element of the node 87 -- (in Right) whose key matched. 88 89 function Capacity (Container : Map) return Count_Type; 90 -- Returns the current capacity of the map. Capacity is the maximum length 91 -- before which rehashing in guaranteed not to occur. 92 93 procedure Reserve_Capacity (Container : in out Map; Capacity : Count_Type); 94 -- If the value of the Capacity actual parameter is less or equal to 95 -- Container.Capacity, then the operation has no effect. Otherwise it 96 -- raises Capacity_Error (as no expansion of capacity is possible for a 97 -- bounded form). 98 99 function Default_Modulus (Capacity : Count_Type) return Hash_Type; 100 -- Returns a modulus value (hash table size) which is optimal for the 101 -- specified capacity (which corresponds to the maximum number of items). 102 103 function Length (Container : Map) return Count_Type; 104 -- Returns the number of items in the map 105 106 function Is_Empty (Container : Map) return Boolean; 107 -- Equivalent to Length (Container) = 0 108 109 procedure Clear (Container : in out Map); 110 -- Removes all of the items from the map. This will deallocate all memory 111 -- associated with this 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 142 private 143 with 144 Implicit_Dereference => Element; 145 146 type Reference_Type (Element : not null access Element_Type) is private 147 with 148 Implicit_Dereference => Element; 149 150 function Constant_Reference 151 (Container : aliased Map; 152 Position : Cursor) return Constant_Reference_Type; 153 154 function Reference 155 (Container : aliased in out Map; 156 Position : Cursor) return Reference_Type; 157 158 function Constant_Reference 159 (Container : aliased Map; 160 Key : Key_Type) return Constant_Reference_Type; 161 162 function Reference 163 (Container : aliased in out Map; 164 Key : Key_Type) return Reference_Type; 165 166 procedure Assign (Target : in out Map; Source : Map); 167 -- If Target denotes the same object as Source, then the operation has no 168 -- effect. If the Target capacity is less than the Source length, then 169 -- Assign raises Capacity_Error. Otherwise, Assign clears Target and then 170 -- copies the (active) elements from Source to Target. 171 172 function Copy 173 (Source : Map; 174 Capacity : Count_Type := 0; 175 Modulus : Hash_Type := 0) return Map; 176 -- Constructs a new set object whose elements correspond to Source. If the 177 -- Capacity parameter is 0, then the capacity of the result is the same as 178 -- the length of Source. If the Capacity parameter is equal or greater than 179 -- the length of Source, then the capacity of the result is the specified 180 -- value. Otherwise, Copy raises Capacity_Error. If the Modulus parameter 181 -- is 0, then the modulus of the result is the value returned by a call to 182 -- Default_Modulus with the capacity parameter determined as above; 183 -- otherwise the modulus of the result is the specified value. 184 185 procedure Move (Target : in out Map; Source : in out Map); 186 -- Clears Target (if it's not empty), and then moves (not copies) the 187 -- buckets array and nodes from Source to Target. 188 189 procedure Insert 190 (Container : in out Map; 191 Key : Key_Type; 192 New_Item : Element_Type; 193 Position : out Cursor; 194 Inserted : out Boolean); 195 -- Conditionally inserts New_Item into the map. If Key is already in the 196 -- map, then Inserted returns False and Position designates the node 197 -- containing the existing key/element pair (neither of which is modified). 198 -- If Key is not already in the map, the Inserted returns True and Position 199 -- designates the newly-inserted node container Key and New_Item. The 200 -- search for the key works as follows. Hash is called to determine Key's 201 -- bucket; if the bucket is non-empty, then Equivalent_Keys is called to 202 -- compare Key to each node in that bucket. If the bucket is empty, or 203 -- there were no matching keys in the bucket, the search "fails" and the 204 -- key/item pair is inserted in the map (and Inserted returns True); 205 -- otherwise, the search "succeeds" (and Inserted returns False). 206 207 procedure Insert 208 (Container : in out Map; 209 Key : Key_Type; 210 Position : out Cursor; 211 Inserted : out Boolean); 212 -- The same as the (conditional) Insert that accepts an element parameter, 213 -- with the difference that if Inserted returns True, then the element of 214 -- the newly-inserted node is initialized to its default value. 215 216 procedure Insert 217 (Container : in out Map; 218 Key : Key_Type; 219 New_Item : Element_Type); 220 -- Attempts to insert Key into the map, performing the usual search (which 221 -- involves calling both Hash and Equivalent_Keys); if the search succeeds 222 -- (because Key is already in the map), then it raises Constraint_Error. 223 -- (This version of Insert is similar to Replace, but having the opposite 224 -- exception behavior. It is intended for use when you want to assert that 225 -- Key is not already in the map.) 226 227 procedure Include 228 (Container : in out Map; 229 Key : Key_Type; 230 New_Item : Element_Type); 231 -- Attempts to insert Key into the map. If Key is already in the map, then 232 -- both the existing key and element are assigned the values of Key and 233 -- New_Item, respectively. (This version of Insert only raises an exception 234 -- if cursor tampering occurs. It is intended for use when you want to 235 -- insert the key/element pair in the map, and you don't care whether Key 236 -- is already present.) 237 238 procedure Replace 239 (Container : in out Map; 240 Key : Key_Type; 241 New_Item : Element_Type); 242 -- Searches for Key in the map; if the search fails (because Key was not in 243 -- the map), then it raises Constraint_Error. Otherwise, both the existing 244 -- key and element are assigned the values of Key and New_Item rsp. (This 245 -- is similar to Insert, but with the opposite exception behavior. It is to 246 -- be used when you want to assert that Key is already in the map.) 247 248 procedure Exclude (Container : in out Map; Key : Key_Type); 249 -- Searches for Key in the map, and if found, removes its node from the map 250 -- and then deallocates it. The search works as follows. The operation 251 -- calls Hash to determine the key's bucket; if the bucket is not empty, it 252 -- calls Equivalent_Keys to compare Key to each key in the bucket. (This is 253 -- the deletion analog of Include. It is intended for use when you want to 254 -- remove the item from the map, but don't care whether the key is already 255 -- in the map.) 256 257 procedure Delete (Container : in out Map; Key : Key_Type); 258 -- Searches for Key in the map (which involves calling both Hash and 259 -- Equivalent_Keys). If the search fails, then the operation raises 260 -- Constraint_Error. Otherwise it removes the node from the map and then 261 -- deallocates it. (This is the deletion analog of non-conditional 262 -- Insert. It is intended for use when you want to assert that the item is 263 -- already in the map.) 264 265 procedure Delete (Container : in out Map; Position : in out Cursor); 266 -- Removes the node designated by Position from the map, and then 267 -- deallocates the node. The operation calls Hash to determine the bucket, 268 -- and then compares Position to each node in the bucket until there's a 269 -- match (it does not call Equivalent_Keys). 270 271 function First (Container : Map) return Cursor; 272 -- Returns a cursor that designates the first non-empty bucket, by 273 -- searching from the beginning of the buckets array. 274 275 function Next (Position : Cursor) return Cursor; 276 -- Returns a cursor that designates the node that follows the current one 277 -- designated by Position. If Position designates the last node in its 278 -- bucket, the operation calls Hash to compute the index of this bucket, 279 -- and searches the buckets array for the first non-empty bucket, starting 280 -- from that index; otherwise, it simply follows the link to the next node 281 -- in the same bucket. 282 283 procedure Next (Position : in out Cursor); 284 -- Equivalent to Position := Next (Position) 285 286 function Find (Container : Map; Key : Key_Type) return Cursor; 287 -- Searches for Key in the map. Find calls Hash to determine the key's 288 -- bucket; if the bucket is not empty, it calls Equivalent_Keys to compare 289 -- Key to each key in the bucket. If the search succeeds, Find returns a 290 -- cursor designating the matching node; otherwise, it returns No_Element. 291 292 function Contains (Container : Map; Key : Key_Type) return Boolean; 293 -- Equivalent to Find (Container, Key) /= No_Element 294 295 function Element (Container : Map; Key : Key_Type) return Element_Type; 296 -- Equivalent to Element (Find (Container, Key)) 297 298 function Equivalent_Keys (Left, Right : Cursor) return Boolean; 299 -- Returns the result of calling Equivalent_Keys with the keys of the nodes 300 -- designated by cursors Left and Right. 301 302 function Equivalent_Keys (Left : Cursor; Right : Key_Type) return Boolean; 303 -- Returns the result of calling Equivalent_Keys with key of the node 304 -- designated by Left and key Right. 305 306 function Equivalent_Keys (Left : Key_Type; Right : Cursor) return Boolean; 307 -- Returns the result of calling Equivalent_Keys with key Left and the node 308 -- designated by Right. 309 310 procedure Iterate 311 (Container : Map; 312 Process : not null access procedure (Position : Cursor)); 313 -- Calls Process for each node in the map 314 315 function Iterate (Container : Map) 316 return Map_Iterator_Interfaces.Forward_Iterator'class; 317 318private 319 pragma Inline (Length); 320 pragma Inline (Is_Empty); 321 pragma Inline (Clear); 322 pragma Inline (Key); 323 pragma Inline (Element); 324 pragma Inline (Move); 325 pragma Inline (Contains); 326 pragma Inline (Capacity); 327 pragma Inline (Reserve_Capacity); 328 pragma Inline (Has_Element); 329 pragma Inline (Next); 330 331 type Node_Type is record 332 Key : Key_Type; 333 Element : aliased Element_Type; 334 Next : Count_Type; 335 end record; 336 337 package HT_Types is 338 new Hash_Tables.Generic_Bounded_Hash_Table_Types (Node_Type); 339 340 type Map (Capacity : Count_Type; Modulus : Hash_Type) is 341 new HT_Types.Hash_Table_Type (Capacity, Modulus) with null record; 342 343 use HT_Types, HT_Types.Implementation; 344 use Ada.Streams; 345 use Ada.Finalization; 346 347 procedure Write 348 (Stream : not null access Root_Stream_Type'Class; 349 Container : Map); 350 351 for Map'Write use Write; 352 353 procedure Read 354 (Stream : not null access Root_Stream_Type'Class; 355 Container : out Map); 356 357 for Map'Read use Read; 358 359 type Map_Access is access all Map; 360 for Map_Access'Storage_Size use 0; 361 362 -- Note: If a Cursor object has no explicit initialization expression, 363 -- it must default initialize to the same value as constant No_Element. 364 -- The Node component of type Cursor has scalar type Count_Type, so it 365 -- requires an explicit initialization expression of its own declaration, 366 -- in order for objects of record type Cursor to properly initialize. 367 368 type Cursor is record 369 Container : Map_Access; 370 Node : Count_Type := 0; 371 end record; 372 373 procedure Read 374 (Stream : not null access Root_Stream_Type'Class; 375 Item : out Cursor); 376 377 for Cursor'Read use Read; 378 379 procedure Write 380 (Stream : not null access Root_Stream_Type'Class; 381 Item : Cursor); 382 383 for Cursor'Write use Write; 384 385 subtype Reference_Control_Type is Implementation.Reference_Control_Type; 386 -- It is necessary to rename this here, so that the compiler can find it 387 388 type Constant_Reference_Type 389 (Element : not null access constant Element_Type) is 390 record 391 Control : Reference_Control_Type := 392 raise Program_Error with "uninitialized reference"; 393 -- The RM says, "The default initialization of an object of 394 -- type Constant_Reference_Type or Reference_Type propagates 395 -- Program_Error." 396 end record; 397 398 procedure Write 399 (Stream : not null access Root_Stream_Type'Class; 400 Item : Constant_Reference_Type); 401 402 for Constant_Reference_Type'Write use Write; 403 404 procedure Read 405 (Stream : not null access Root_Stream_Type'Class; 406 Item : out Constant_Reference_Type); 407 408 for Constant_Reference_Type'Read use Read; 409 410 type Reference_Type (Element : not null access Element_Type) is record 411 Control : Reference_Control_Type := 412 raise Program_Error with "uninitialized reference"; 413 -- The RM says, "The default initialization of an object of 414 -- type Constant_Reference_Type or Reference_Type propagates 415 -- Program_Error." 416 end record; 417 418 procedure Write 419 (Stream : not null access Root_Stream_Type'Class; 420 Item : Reference_Type); 421 422 for Reference_Type'Write use Write; 423 424 procedure Read 425 (Stream : not null access Root_Stream_Type'Class; 426 Item : out Reference_Type); 427 428 for Reference_Type'Read use Read; 429 430 -- Three operations are used to optimize in the expansion of "for ... of" 431 -- loops: the Next(Cursor) procedure in the visible part, and the following 432 -- Pseudo_Reference and Get_Element_Access functions. See Sem_Ch5 for 433 -- details. 434 435 function Pseudo_Reference 436 (Container : aliased Map'Class) return Reference_Control_Type; 437 pragma Inline (Pseudo_Reference); 438 -- Creates an object of type Reference_Control_Type pointing to the 439 -- container, and increments the Lock. Finalization of this object will 440 -- decrement the Lock. 441 442 type Element_Access is access all Element_Type with 443 Storage_Size => 0; 444 445 function Get_Element_Access 446 (Position : Cursor) return not null Element_Access; 447 -- Returns a pointer to the element designated by Position. 448 449 Empty_Map : constant Map := 450 (Hash_Table_Type with Capacity => 0, Modulus => 0); 451 452 No_Element : constant Cursor := (Container => null, Node => 0); 453 454 type Iterator is new Limited_Controlled and 455 Map_Iterator_Interfaces.Forward_Iterator with 456 record 457 Container : Map_Access; 458 end record 459 with Disable_Controlled => not T_Check; 460 461 overriding procedure Finalize (Object : in out Iterator); 462 463 overriding function First (Object : Iterator) return Cursor; 464 465 overriding function Next 466 (Object : Iterator; 467 Position : Cursor) return Cursor; 468 469end Ada.Containers.Bounded_Hashed_Maps; 470