AmigActive 3/AACD03.BIN/AACD/Programming/sofa/archive/SmallEiffel.lha/SmallEiffel/lib_std/collection.e

Text File | 1999-06-05 | 13KB | 472 lines

-- This file is  free  software, which  comes  along  with  SmallEiffel. This
-- software  is  distributed  in the hope that it will be useful, but WITHOUT
-- ANY  WARRANTY;  without  even  the  implied warranty of MERCHANTABILITY or
-- FITNESS  FOR A PARTICULAR PURPOSE. You can modify it as you want, provided
-- this header is kept unaltered, and a notification of the changes is added.
-- You  are  allowed  to  redistribute  it and sell it, alone or as a part of
-- another product.
--          Copyright (C) 1994-98 LORIA - UHP - CRIN - INRIA - FRANCE
--            Dominique COLNET and Suzanne COLLIN - [e-mail]
--                       http://SmallEiffel.loria.fr
--
deferred class COLLECTION[E]
--
-- Common abstract definition of a sequentiable collection of
-- objects. Such a collection is traversable using a simple
-- INTEGER index from `lower' to `upper'. Items can be added,
-- changed or removed.
--
-- The SmallEiffel standard library (lib_std) provides four
-- implementations : ARRAY[E], FIXED_ARRAY[E], LINK_LIST[E]
-- and LINK2_LIST[E]. All implementations have exactly the
-- same behavior. Switching from one implementation to another
-- only change the memory used and the execution time.
--

inherit
   ANY
      undefine copy, is_equal
      redefine fill_tagged_out_memory
      end;

feature -- Indexing :

   lower: INTEGER is
         -- Lower index bound.
      deferred
      end;

   upper: INTEGER is
         -- Upper index bound.
      deferred
      end;

   frozen valid_index(index: INTEGER): BOOLEAN is
         -- True when `index' is valid (ie. inside actual
         -- bounds of the collection).
      do
         Result := lower <= index and then index <= upper;
      ensure
         Result = (lower <= index and then index <= upper);
      end;

feature -- Counting :

   count: INTEGER is
         -- Number of elements actually stored in the collection.
      deferred
      ensure
         Result = upper - lower + 1
      end;

   empty: BOOLEAN is
         -- Is collection empty?
      do
         Result := (count = 0);
      end;

feature -- Accessing :

   item, infix "@" (index: INTEGER): E is
         -- Item at position `index'.
      require
         valid_index(index)
      deferred
      end;

   first: like item is
         -- The very `first' item.
      require
         count >= 1
      deferred
      ensure
         Result = item(lower)
      end;

   last: like item is
         -- The `last' item.
      require
         count >= 1
      deferred
      ensure
         Result = item(upper)
      end;

feature -- Writing :

   put(element: like item; index: INTEGER) is
         -- Put `element' at position `index'.
      require
         valid_index(index)
      deferred
      ensure
         item(index) = element;
         count = old count
      end;

   swap(i1, i2: INTEGER) is
         -- Swap item at index `i1' with item at index `i2'.
      require
         valid_index(i1);
         valid_index(i2)
      local
         tmp: like item;
      do
         tmp := item(i1);
         put(item(i2),i1);
         put(tmp,i2);
      ensure
         item(i1) = old item(i2);
         item(i2) = old item(i1);
         count = old count
      end;

   set_all_with(v: like item) is
         -- Set all items with value `v'.
      deferred
      ensure
         count = old count
      end;

   set_slice_with(v: like item; lower_index, upper_index: INTEGER) is
         -- Set all items in range [`lower_index' .. `upper_index'] with `v'.
      require
         lower_index <= upper_index;
         valid_index(lower_index);
         valid_index(upper_index)
      local
         i: INTEGER;
      do
         from
            i := lower_index;
         until
            i > upper_index
         loop
            put(v,i);
            i := i + 1;
         end;
      ensure
         count = old count
      end;

   clear_all is
         -- Set all items to default values.
         -- The `count' is not affected (see also `clear').
      local
         value: like item;
      do
         set_all_with(value);
      ensure
         count = old count;
         all_cleared
      end;

feature -- Adding :

   add_first(element: like item) is
         -- Add a new item in first position : `count' is increased by
         -- one and all other items are shifted right.
      deferred
      ensure
         first = element;
         count = 1 + old count;
         lower = old lower;
         upper = 1 + old upper
      end;

   add_last(element: like item) is
         -- Add a new item at the end : `count' is increased by one.
      deferred
      ensure
         last = element;
         count = 1 + old count;
         lower = old lower;
         upper = 1 + old upper
      end;

   add(element: like item; index: INTEGER) is
         -- Add a new `element' at rank `index' : `count' is increased
         -- by one and range [`index' .. `upper'] is shifted right
         -- by one position.
      require
         lower <= index;
         index <= upper + 1
      deferred
      ensure
         item(index) = element;
         count = 1 + old count;
         upper = 1 + old upper
      end;

feature -- Modification :

   force(element: E; index: INTEGER) is
         -- Put `element' at position `index'. Collection is
         -- resized if `index' is not inside current bounds.
         -- New bounds are initialized with default values.
      require
         index >= lower
      deferred
      ensure
         valid_index(index);
         item(index) = element
      end;

   from_collection(model: COLLECTION[like item]) is
      -- Initialize the current object with the contents of `model'.
      require
         model /= Void
      deferred
      ensure
         count = model.count;
      end;

feature -- Removing :

   remove_first is
         -- Remove the `first' element of the collection.
      require
         not empty
      deferred
      ensure
         count = (old count) - 1;
         (lower = (old lower) + 1) xor (upper = (old upper) - 1)
      end;

   remove(index: INTEGER) is
         -- Remove the item at position `index'. Followings items
         -- are shifted left by one position.
      require
         valid_index(index)
      deferred
      ensure
         count = (old count) - 1;
         upper = (old upper) - 1;
      end;

   remove_last is
         -- Remove the `last' item.
      require
         not empty;
      deferred
      ensure
         count = (old count) - 1;
         upper = (old upper) - 1
      end;

   clear is
         -- Discard all items in order to make it `empty'.
         -- See also `clear_all'.
      deferred
      ensure
         empty;
      end;

feature -- Looking and Searching :

   has(x: like item): BOOLEAN is
         -- Look for `x' using `equal' for comparison.
         -- Also consider `fast_has' to choose the most appropriate.
      do
         Result := valid_index(index_of(x));
      end;

   fast_has(x: like item): BOOLEAN is
         -- Look for `x' using basic `=' for comparison.
         -- Also consider `has' to choose the most appropriate.
      do
         Result := valid_index(fast_index_of(x));
      end;

   index_of(element: like item): INTEGER is
         -- Give the index of the first occurrence of `element' using
         -- `is_equal' for comparison.
         -- Answer `upper + 1' when `element' is not inside.
         -- Also consider `fast_index_of' to choose the most appropriate.
      deferred
      ensure
         lower <= Result;
         Result <= upper + 1;
         Result <= upper implies equal(element,item(Result));
      end;

   fast_index_of(element: like item): INTEGER is
         -- Give the index of the first occurrence of `element' using
         -- basic `=' for comparison.
         -- Answer `upper + 1' when `element' is not inside.
         -- Also consider `index_of' to choose the most appropriate.
      deferred
      ensure
         lower <= Result;
         Result <= upper + 1;
         Result <= upper implies element = item(Result);
      end;

feature -- Looking and comparison :

   all_cleared: BOOLEAN is
         -- Are all items set to the default value ?
      deferred
      end;

   nb_occurrences(element: like item): INTEGER is
         -- Number of occurrences of `element' using `equal' for comparison.
         -- Also consider `fast_nb_occurences' to choose the most appropriate.
      deferred
      ensure
         Result >= 0
      end;

   fast_nb_occurrences(element: like item): INTEGER is
         -- Number of occurrences of `element' using basic `=' for comparison.
         -- Also consider `nb_occurences' to choose the most appropriate.
      deferred
      ensure
         Result >= 0;
      end;

feature -- Printing :

   frozen fill_tagged_out_memory is
      local
         i: INTEGER;
         v: like item;
      do
         tagged_out_memory.append("lower: ");
         lower.append_in(tagged_out_memory);
         tagged_out_memory.append(" upper: ");
         upper.append_in(tagged_out_memory);
         tagged_out_memory.append(" [");
         from
            i := lower;
         until
            i > upper or else tagged_out_memory.count > 2048
         loop
            v := item(i);
            if v = Void then
               tagged_out_memory.append("Void");
            else
               v.out_in_tagged_out_memory;
            end;
            if i < upper then
               tagged_out_memory.extend(' ');
            end;
            i := i + 1;
         end;
         if i <= upper then
            tagged_out_memory.append(" ...");
         end;
         tagged_out_memory.extend(']');
      end;

feature -- Other Features :

   replace_all(old_value, new_value: like item) is
         -- Replace all occurences of the element `old_value' by `new_value'
         -- using `equal' for comparison.
         -- See also `fast_replace_all' to choose the apropriate one.
      deferred
      ensure
         count = old count;
         nb_occurrences(old_value) = 0
      end;

   fast_replace_all(old_value, new_value: like item) is
         -- Replace all occurences of the element `old_value' by `new_value'
         -- using operator `=' for comparison.
         -- See also `replace_all' to choose the apropriate one.
      deferred
      ensure
         count = old count;
         fast_nb_occurrences(old_value) = 0
      end;

   move(lower_index, upper_index, distance: INTEGER) is
         -- Move range `lower_index' .. `upper_index' by `distance'
         -- positions. Negative distance moves towards lower indices.
         -- Free places get default values.
      require
         lower_index <= upper_index;
         valid_index(lower_index);
         valid_index(lower_index + distance);
         valid_index(upper_index);
         valid_index(upper_index + distance)
      local
         default_value: like item;
         i: INTEGER;
      do
         if distance = 0 then
         elseif distance < 0 then
            from
               i := lower_index;
            until
               i > upper_index
            loop
               put(item(i),i + distance);
               put(default_value,i);
               i := i + 1;
            end;
         else
            from
               i := upper_index;
            until
               i < lower_index
            loop
               put(item(i),i + distance);
               put(default_value,i);
               i := i - 1;
            end;
         end;
      ensure
         count = old count
      end;

   slice(low, up: INTEGER): like Current is
         -- Create a new collection initialized with elements of
         -- range `low'..`up'. Result has the same dynamic type
         -- as Current collection. The `lower' index of the new
         -- collection is the same as `lower' of Current.
      require
         valid_index(low);
         valid_index(up);
         low <= up
      deferred
      ensure
         same_type(Result);
         Result.count = up - low + 1;
         Result.lower = lower
      end;

feature -- The Guru section :

   free is
         -- Free the memory used by the Current COLLECTION (objects
         -- pointed by the Current COLLECTION are not affected).
         -- Assume you don't use Current any more.
      obsolete "Since release -0.81, the Garbage Collector is %
               %implemented. This feature will be soon removed."
      deferred
      end;

feature {NONE}

   frozen equal_like(e1, e2: like item): BOOLEAN is
         -- Note: this feature is called to avoid calling `equal'
         -- on expanded types (no automatic conversion to
         -- corresponding reference type).
      do
         if e1.is_basic_expanded_type then
            Result := e1 = e2;
         elseif e1.is_expanded_type then
            Result := e1.is_equal(e2);
         elseif e1 = e2 then
            Result := true;
         elseif e1 = Void or else e2 = Void then
         else
            Result := e1.is_equal(e2);
         end;
      end;

end -- COLLECTION[E]