From 9415fcdad101c8c47f777345595d2306344cd9a1 Mon Sep 17 00:00:00 2001 From: Raphael Amiard Date: Thu, 19 Sep 2019 08:13:10 +0000 Subject: [PATCH] [Ada] Propagate documentation to formal bounded sets 2019-09-19 Raphael Amiard gcc/ada/ * libgnat/a-cfhase.ads (Set): Add comments to public primitives. From-SVN: r275937 --- gcc/ada/ChangeLog | 4 + gcc/ada/libgnat/a-cfhase.ads | 139 +++++++++++++++++++++++++++++++++++ 2 files changed, 143 insertions(+) diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog index f9a8bfe7583..2e302299660 100644 --- a/gcc/ada/ChangeLog +++ b/gcc/ada/ChangeLog @@ -1,3 +1,7 @@ +2019-09-19 Raphael Amiard + + * libgnat/a-cfhase.ads (Set): Add comments to public primitives. + 2019-09-19 Raphael Amiard * libgnat/a-cbhama.ads, libgnat/a-cbhase.ads, diff --git a/gcc/ada/libgnat/a-cfhase.ads b/gcc/ada/libgnat/a-cfhase.ads index 5eb673ae72b..3e72aef0d6c 100644 --- a/gcc/ada/libgnat/a-cfhase.ads +++ b/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, -- 2.30.2