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Commit 9415fcda by Raphael Amiard Committed by Pierre-Marie de Rodat
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[Ada] Propagate documentation to formal bounded sets 

2019-09-19  Raphael Amiard  <amiard@adacore.com>

gcc/ada/

	* libgnat/a-cfhase.ads (Set): Add comments to public primitives.

From-SVN: r275937
parent 3aacb9ed
Showing with 143 additions and 0 deletions
gcc/ada/ChangeLog
2019-09-19 Raphael Amiard <amiard@adacore.com>
* libgnat/a-cfhase.ads (Set): Add comments to public primitives.
2019-09-19 Raphael Amiard <amiard@adacore.com>
* libgnat/a-cbhama.ads, libgnat/a-cbhase.ads,
libgnat/a-chtgop.ads (Clear): Refine comments
......
gcc/ada/libgnat/a-cfhase.ads
......@@ -355,10 +355,24 @@ is
"="'Result =
(E_Elements_Included (Elements (Left), Elements (Right))
and E_Elements_Included (Elements (Right), Elements (Left)));
-- For each element in Left, set equality attempts to find the equal
-- element in Right; if a search fails, then set equality immediately
-- returns False. The search works by calling Hash to find the bucket in
-- the Right set that corresponds to the Left element. If the bucket is
-- non-empty, the search calls the generic formal element equality operator
-- to compare the element (in Left) to the element of each node in the
-- bucket (in Right); the search terminates when a matching node in the
-- bucket is found, or the nodes in the bucket are exhausted. (Note that
-- element equality is called here, not Equivalent_Elements. Set equality
-- is the only operation in which element equality is used. Compare set
-- equality to Equivalent_Sets, which does call Equivalent_Elements.)
function Equivalent_Sets (Left, Right : Set) return Boolean with
Global => null,
Post => Equivalent_Sets'Result = (Model (Left) = Model (Right));
-- Similar to set equality, with the difference that the element in Left is
-- compared to the elements in Right using the generic formal
-- Equivalent_Elements operation instead of element equality.
function To_Set (New_Item : Element_Type) return Set with
Global => null,
......@@ -366,10 +380,14 @@ is
M.Is_Singleton (Model (To_Set'Result), New_Item)
and Length (To_Set'Result) = 1
and E.Get (Elements (To_Set'Result), 1) = New_Item;
-- Constructs a singleton set comprising New_Element. To_Set calls Hash to
-- determine the bucket for New_Item.
function Capacity (Container : Set) return Count_Type with
Global => null,
Post => Capacity'Result = Container.Capacity;
-- Returns the current capacity of the set. Capacity is the maximum length
-- before which rehashing in guaranteed not to occur.
procedure Reserve_Capacity
(Container : in out Set;
......@@ -387,14 +405,21 @@ is
(Elements (Container), Elements (Container)'Old)
and E_Elements_Included
(Elements (Container)'Old, Elements (Container));
-- If the value of the Capacity actual parameter is less or equal to
-- Container.Capacity, then the operation has no effect. Otherwise it
-- raises Capacity_Error (as no expansion of capacity is possible for a
-- bounded form).
function Is_Empty (Container : Set) return Boolean with
Global => null,
Post => Is_Empty'Result = (Length (Container) = 0);
-- Equivalent to Length (Container) = 0
procedure Clear (Container : in out Set) with
Global => null,
Post => Length (Container) = 0 and M.Is_Empty (Model (Container));
-- Removes all of the items from the set. This will deallocate all memory
-- associated with this set.
procedure Assign (Target : in out Set; Source : Set) with
Global => null,
......@@ -407,6 +432,10 @@ is
and E_Elements_Included (Elements (Target), Elements (Source))
and E_Elements_Included (Elements (Source), Elements (Target));
-- If Target denotes the same object as Source, then the operation has no
-- effect. If the Target capacity is less than the Source length, then
-- Assign raises Capacity_Error. Otherwise, Assign clears Target and then
-- copies the (active) elements from Source to Target.
function Copy
(Source : Set;
......@@ -422,6 +451,14 @@ is
Copy'Result.Capacity = Source.Capacity
else
Copy'Result.Capacity = Capacity);
-- Constructs a new set object whose elements correspond to Source. If the
-- Capacity parameter is 0, then the capacity of the result is the same as
-- the length of Source. If the Capacity parameter is equal or greater than
-- the length of Source, then the capacity of the result is the specified
-- value. Otherwise, Copy raises Capacity_Error. If the Modulus parameter
-- is 0, then the modulus of the result is the value returned by a call to
-- Default_Modulus with the capacity parameter determined as above;
-- otherwise the modulus of the result is the specified value.
function Element
(Container : Set;
......@@ -485,6 +522,8 @@ is
and E_Elements_Included (Elements (Target), Elements (Source)'Old)
and E_Elements_Included (Elements (Source)'Old, Elements (Target));
-- Clears Target (if it's not empty), and then moves (not copies) the
-- buckets array and nodes from Source to Target.
procedure Insert
(Container : in out Set;
......@@ -541,6 +580,18 @@ is
(Positions (Container),
Positions (Container)'Old,
Position));
-- Conditionally inserts New_Item into the set. If New_Item is already in
-- the set, then Inserted returns False and Position designates the node
-- containing the existing element (which is not modified). If New_Item is
-- not already in the set, then Inserted returns True and Position
-- designates the newly-inserted node containing New_Item. The search for
-- an existing element works as follows. Hash is called to determine
-- New_Item's bucket; if the bucket is non-empty, then Equivalent_Elements
-- is called to compare New_Item to the element of each node in that
-- bucket. If the bucket is empty, or there were no equivalent elements in
-- the bucket, the search "fails" and the New_Item is inserted in the set
-- (and Inserted returns True); otherwise, the search "succeeds" (and
-- Inserted returns False).
procedure Insert (Container : in out Set; New_Item : Element_Type) with
Global => null,
......@@ -570,6 +621,13 @@ is
(Positions (Container),
Positions (Container)'Old,
Find (Container, New_Item));
-- Attempts to insert New_Item into the set, performing the usual insertion
-- search (which involves calling both Hash and Equivalent_Elements); if
-- the search succeeds (New_Item is equivalent to an element already in the
-- set, and so was not inserted), then this operation raises
-- Constraint_Error. (This version of Insert is similar to Replace, but
-- having the opposite exception behavior. It is intended for use when you
-- want to assert that the item is not already in the set.)
procedure Include (Container : in out Set; New_Item : Element_Type) with
Global => null,
......@@ -625,6 +683,13 @@ is
(Positions (Container),
Positions (Container)'Old,
Find (Container, New_Item)));
-- Attempts to insert New_Item into the set. If an element equivalent to
-- New_Item is already in the set (the insertion search succeeded, and
-- hence New_Item was not inserted), then the value of New_Item is assigned
-- to the existing element. (This insertion operation only raises an
-- exception if cursor tampering occurs. It is intended for use when you
-- want to insert the item in the set, and you don't care whether an
-- equivalent element is already present.)
procedure Replace (Container : in out Set; New_Item : Element_Type) with
Global => null,
......@@ -648,6 +713,12 @@ is
(Elements (Container)'Old,
Elements (Container),
P.Get (Positions (Container), Find (Container, New_Item)));
-- Searches for New_Item in the set; if the search fails (because an
-- equivalent element was not in the set), then it raises
-- Constraint_Error. Otherwise, the existing element is assigned the value
-- New_Item. (This is similar to Insert, but with the opposite exception
-- behavior. It is intended for use when you want to assert that the item
-- is already in the set.)
procedure Exclude (Container : in out Set; Item : Element_Type) with
Global => null,
......@@ -685,6 +756,13 @@ is
(Positions (Container)'Old,
Positions (Container),
Find (Container, Item)'Old));
-- Searches for Item in the set, and if found, removes its node from the
-- set and then deallocates it. The search works as follows. The operation
-- calls Hash to determine the item's bucket; if the bucket is not empty,
-- it calls Equivalent_Elements to compare Item to the element of each node
-- in the bucket. (This is the deletion analog of Include. It is intended
-- for use when you want to remove the item from the set, but don't care
-- whether the item is already in the set.)
procedure Delete (Container : in out Set; Item : Element_Type) with
Global => null,
......@@ -715,6 +793,12 @@ is
(Positions (Container)'Old,
Positions (Container),
Find (Container, Item)'Old);
-- Searches for Item in the set (which involves calling both Hash and
-- Equivalent_Elements). If the search fails, then the operation raises
-- Constraint_Error. Otherwise it removes the node from the set and then
-- deallocates it. (This is the deletion analog of non-conditional
-- Insert. It is intended for use when you want to assert that the item is
-- already in the set.)
procedure Delete (Container : in out Set; Position : in out Cursor) with
Global => null,
......@@ -747,6 +831,10 @@ is
(Positions (Container)'Old,
Positions (Container),
Position'Old);
-- Removes the node designated by Position from the set, and then
-- deallocates the node. The operation calls Hash to determine the bucket,
-- and then compares Position to each node in the bucket until there's a
-- match (it does not call Equivalent_Elements).
procedure Union (Target : in out Set; Source : Set) with
Global => null,
......@@ -795,6 +883,8 @@ is
E_Right => Elements (Target),
P_Left => Positions (Target)'Old,
P_Right => Positions (Target));
-- Iterates over the Source set, and conditionally inserts each element
-- into Target.
function Union (Left, Right : Set) return Set with
Global => null,
......@@ -831,6 +921,8 @@ is
Model (Left),
Elements (Right),
Elements (Union'Result));
-- The operation first copies the Left set to the result, and then iterates
-- over the Right set to conditionally insert each element into the result.
function "or" (Left, Right : Set) return Set renames Union;
......@@ -866,6 +958,9 @@ is
E_Right => Elements (Target)'Old,
P_Left => Positions (Target),
P_Right => Positions (Target)'Old);
-- Iterates over the Target set (calling First and Next), calling Find to
-- determine whether the element is in Source. If an equivalent element is
-- not found in Source, the element is deleted from Target.
function Intersection (Left, Right : Set) return Set with
Global => null,
......@@ -891,6 +986,9 @@ is
and E_Elements_Included
(Elements (Left), Model (Right),
Elements (Intersection'Result));
-- Iterates over the Left set, calling Find to determine whether the
-- element is in Right. If an equivalent element is found, it is inserted
-- into the result set.
function "and" (Left, Right : Set) return Set renames Intersection;
......@@ -926,6 +1024,9 @@ is
E_Right => Elements (Target)'Old,
P_Left => Positions (Target),
P_Right => Positions (Target)'Old);
-- Iterates over the Source (calling First and Next), calling Find to
-- determine whether the element is in Target. If an equivalent element is
-- found, it is deleted from Target.
function Difference (Left, Right : Set) return Set with
Global => null,
......@@ -955,6 +1056,9 @@ is
(Elements (Left),
Model (Difference'Result),
Elements (Difference'Result));
-- Iterates over the Left set, calling Find to determine whether the
-- element is in the Right set. If an equivalent element is not found, the
-- element is inserted into the result set.
function "-" (Left, Right : Set) return Set renames Difference;
......@@ -995,6 +1099,10 @@ is
and E_Elements_Included
(Elements (Source), Model (Target), Elements (Target));
-- The operation iterates over the Source set, searching for the element
-- in Target (calling Hash and Equivalent_Elements). If an equivalent
-- element is found, it is removed from Target; otherwise it is inserted
-- into Target.
function Symmetric_Difference (Left, Right : Set) return Set with
Global => null,
......@@ -1042,6 +1150,12 @@ is
(Elements (Right),
Model (Symmetric_Difference'Result),
Elements (Symmetric_Difference'Result));
-- The operation first iterates over the Left set. It calls Find to
-- determine whether the element is in the Right set. If no equivalent
-- element is found, the element from Left is inserted into the result. The
-- operation then iterates over the Right set, to determine whether the
-- element is in the Left set. If no equivalent element is found, the Right
-- element is inserted into the result.
function "xor" (Left, Right : Set) return Set
renames Symmetric_Difference;
......@@ -1050,10 +1164,21 @@ is
Global => null,
Post =>
Overlap'Result = not (M.No_Overlap (Model (Left), Model (Right)));
-- Iterates over the Left set (calling First and Next), calling Find to
-- determine whether the element is in the Right set. If an equivalent
-- element is found, the operation immediately returns True. The operation
-- returns False if the iteration over Left terminates without finding any
-- equivalent element in Right.
function Is_Subset (Subset : Set; Of_Set : Set) return Boolean with
Global => null,
Post => Is_Subset'Result = (Model (Subset) <= Model (Of_Set));
-- Iterates over Subset (calling First and Next), calling Find to determine
-- whether the element is in Of_Set. If no equivalent element is found in
-- Of_Set, the operation immediately returns False. The operation returns
-- True if the iteration over Subset terminates without finding an element
-- not in Of_Set (that is, every element in Subset is equivalent to an
-- element in Of_Set).
function First (Container : Set) return Cursor with
Global => null,
......@@ -1064,6 +1189,8 @@ is
others =>
Has_Element (Container, First'Result)
and P.Get (Positions (Container), First'Result) = 1);
-- Returns a cursor that designates the first non-empty bucket, by
-- searching from the beginning of the buckets array.
function Next (Container : Set; Position : Cursor) return Cursor with
Global => null,
......@@ -1079,6 +1206,12 @@ is
Has_Element (Container, Next'Result)
and then P.Get (Positions (Container), Next'Result) =
P.Get (Positions (Container), Position) + 1);
-- Returns a cursor that designates the node that follows the current one
-- designated by Position. If Position designates the last node in its
-- bucket, the operation calls Hash to compute the index of this bucket,
-- and searches the buckets array for the first non-empty bucket, starting
-- from that index; otherwise, it simply follows the link to the next node
-- in the same bucket.
procedure Next (Container : Set; Position : in out Cursor) with
Global => null,
......@@ -1094,6 +1227,7 @@ is
Has_Element (Container, Position)
and then P.Get (Positions (Container), Position) =
P.Get (Positions (Container), Position'Old) + 1);
-- Equivalent to Position := Next (Position)
function Find
(Container : Set;
......@@ -1118,6 +1252,11 @@ is
and Equivalent_Elements
(Element (Container, Find'Result), Item));
-- Searches for Item in the set. Find calls Hash to determine the item's
-- bucket; if the bucket is not empty, it calls Equivalent_Elements to
-- compare Item to each element in the bucket. If the search succeeds, Find
-- returns a cursor designating the node containing the equivalent element;
-- otherwise, it returns No_Element.
function Contains (Container : Set; Item : Element_Type) return Boolean with
Global => null,
......
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