----------------------------------------------------------------------
-- Copyright 1987 by the Swiss Federal Institute of Technology (EPFL),
-- Prof. A. Strohmeier, EPFL-DI-LGL, CH-1015 Lausanne, Switzerland.
----------------------------------------------------------------------

-- Title    : Generic Package for Tables of Strings Associated with Values.
-- Revision : 13-Jul-1992 Ph. Kipfer (PKR), File header format
-- Approval : 03-Dec-1987 C. Genillard.
-- Creation : 13-Aug-1987 A. Strohmeier.

with Table_Of_Dynamic_Keys_And_Dynamic_Values_G;
generic
  type Character_Type is (<>);
  type String_Type is array (Positive range <>)
       of Character_Type;
  with function Less (Left, Right: String_Type) return Boolean;
  -- Defines ordering of strings.
  with function Equals (Left, Right: String_Type) return Boolean;
  -- Defines equality between strings.

  type Value_Type is limited private;
  with procedure Assign (Destination: in out Value_Type; Source: in Value_Type);
  -- Assigns SOURCE to DESTINATION. If needed, DESTINATION has to be destroyed
  -- before assignement, since ASSIGN is called without a previous call to
  -- DESTROY in the implementation of the package.
  with procedure Destroy (Value: in out Value_Type);
package Table_Of_Strings_And_Dynamic_Values_G is

-- OVERVIEW:
--   This package provides associative tables of unlimited dynamic size with
-- entries of type (String_Type, VALUE_TYPE), where VALUE_TYPE is specified by
-- a generic parameter. Such a couple will also be called an item. The string
-- component acts as a key. Its length is varying.
--   The type TABLE_TYPE is implemented in such a way that every object
-- has the implied initial value of an empty table.
--   Two items (s1, v1) and (s2, v2) have same key if and only if
-- EQUALS (s1, s2).
--    A table may not contain duplicate items, that is items with same key.
--   The following consistency condition must be fullfilled by the relational
-- operation LESS and EQUALS:
--   (i)  EQUALS (s1, s2) implies not LESS (s1, s2) and not LESS (s2, s1)
--   (ii) not LESS (s1, s2) and not EQUALS (s1, s2) implies LESS (s2, s1)
--   In our terminology, a static type is a type which is neither a limited
-- type nor an access type. When an actual generic access type is associated
-- with a generic static type, objects would be shared, i.e. only the access
-- value would be stored, without copying the accessed object.
--   On the opposite, a dynamic type may be limited or an access type.
-- However a dynamic type must have the feature that every object has an
-- implied initial value.
--   Depending on the very nature of the type VALUE_TYPE, one of the provided
-- packages has to be used:
-- TABLE_OF_STRINGS_AND_DYNAMIC_VALUES_G
-- TABLE_OF_STRINGS_AND_STATIC_VALUES_G
--
-- CAUTION:
--   Functions which return the value of an item (or part of it) of the
-- structure share the item with the structure and do not return a copy of it.
-- This may have consequences if the type of the item, (or some component of
-- it) is an access type. For instance, when accessing an item by a function
-- call, this item must not be destroyed or modified during the query.
--
-- PRIMITIVES:
--   CONSTRUCTORS:
--     ASSIGN
--     INSERT (2)
--     INSERT_OR_REPLACE_VALUE
--     REPLACE_VALUE (2)
--     REMOVE (3)
--     REMOVE_MIN (3)
--     REMOVE_MAX (3)
--     UPDATE_VALUE_OR_EXCEPTION_G
--     UPDATE_VALUE_OR_STATUS_G
--   QUERIES:
--     SIZE
--     IS_EMPTY
--     IS_PRESENT
--     VALUE
--     GET_VALUE
--     GET_MIN_ITEM
--     GET_MAX_ITEM
--     MIN_KEY
--     GET_MIN_KEY
--     MAX_KEY
--     GET_MAX_KEY
--     GET_LESS_ITEM
--     GET_LESS_OR_EQUAL_ITEM
--     GET_GREATER_ITEM
--     GET_GREATER_OR_EQUAL_ITEM
--     LESS_KEY
--     GET_LESS_KEY
--     LESS_OR_EQUAL_KEY
--     GET_LESS_OR_EQUAL_KEY
--     GREATER_KEY
--     GET_GREATER_KEY
--     GREATER_OR_EQUAL_KEY
--     GET_GREATER_OR_EQUAL_KEY
--   SET_OPERATIONS:
--     SET_OPERATIONS_G
--       UNION
--       INTERSECTION
--       DIFFERENCE
--       SYMMETRIC_DIFFERENCE
--       "=" (set equality)
--       "<" (strict set inclusion)
--       "<=" (set inclusion)
--       ">" (strict set inclusion)
--       ">=" (set inclusion)
--   ITERATORS:
--     TRAVERSE_ASC_G
--     TRAVERSE_DESC_G
--     TRAVERSE_ASC_AND_UPDATE_VALUE_G
--     TRAVERSE_DESC_AND_UPDATE_VALUE_G
--     DISORDER_TRAVERSE_G
--     DISORDER_TRAVERSE_AND_UPDATE_VALUE_G
--   HEAP MANAGEMENT:
--     DESTROY
--     RELEASE_FREE_LIST
--     SET_MAX_FREE_LIST_SIZE
--     FREE_LIST_SIZE
--
-- ALGORITHM:
--    A table is implemented as a balanced search binary tree (AVL-tree)
-- using pointers. The items are sorted in the tree by increasing keys in
-- conformance to inorder.
--    An internal free list is used to avoid returning each free item (i.e.
-- coming from REMOVE) to the system, so long as the length of this list does
-- not exceed MAX_FREE_LIST_SIZE, in which case the free item is immediately
-- returned to the system. When a new item has to be inserted (i.e. by a call
-- to INSERT), an element is recovered from the free list if it is not empty.
-- Otherwise, new space is taken from the system.


  type Table_Type is limited private;

  Duplicate_Item_Error,
  Missing_Item_Error,
  Empty_Structure_Error: exception;
  String_Constraint_Error: exception;

--/ CONSTRUCTORS:

  procedure Assign (Destination: in out Table_Type; Source: in Table_Type);
  -- OVERVIEW:
  --   Begins by a call to DESTROY (DESTINATION) and then copies SOURCE into
  -- DESTINATION. Note the "in out" mode of the formal parameter DESTINATION.

  procedure Insert (Table: in out Table_Type;
                    Key: in String_Type;
                    Value: in Value_Type);
  -- OVERVIEW:
  --   Inserts the couple (KEY, VALUE) into TABLE.
  -- ERROR:
  --   If an entry with the given key is already in the table, then exception
  -- DUPLICATE_ITEM_ERROR is raised.

  procedure Insert (Table: in out Table_Type;
                    Key: in String_Type;
                    Value: in Value_Type;
                    Duplicate_Item: out Boolean);
  -- OVERVIEW:
  --   Inserts the couple (KEY, VALUE) into TABLE. No action is taken and no
  -- error occurs if an entry with the given key is already in the table
  -- except that DUPLICATE_ITEM is set to true.

  procedure Insert_Or_Replace_Value (Table: in out Table_Type;
                                     Key: in String_Type;
                                     Value: in Value_Type);
  -- OVERVIEW:
  --   Inserts the couple (KEY, VALUE) into TABLE if there is no entry with
  -- this key. Otherwise the given VALUE replaces the previous one.

  procedure Replace_Value (Table: in out Table_Type;
                           Key: in String_Type;
                           Value: in Value_Type);
  -- OVERVIEW:
  --   An entry having key KEY is searched for in TABLE. The given VALUE then
  -- replaces the previous one.
  -- ERROR:
  --   If there is no entry with the given key, the exception
  -- MISSING_ITEM_ERROR is raised.

  procedure Replace_Value (Table: in out Table_Type;
                           Key: in String_Type;
                           Value: in Value_Type;
                           Found: out Boolean);
  -- OVERVIEW:
  --   An entry having key KEY is searched for in TABLE. The given VALUE then
  -- replaces the previous one. No action is taken and no error occurs if
  -- there is no entry with the given key, except that FOUND is set to false.

  procedure Remove (Table: in out Table_Type;
                    Key: in String_Type);
  procedure Remove (Table: in out Table_Type;
                    Key: in String_Type;
                    Value: in out Value_Type);
  -- OVERVIEW:
  --   Removes the entry with key KEY from TABLE and returns in parameter
  -- VALUE, if present, the associated VALUE.
  -- ERROR:
  --   If there is no entry with the given key, the exception
  -- MISSING_ITEM_ERROR is raised.


  procedure Remove (Table: in out Table_Type;
                    Key: in String_Type;
                    Found: out Boolean);
  -- OVERVIEW:
  --   Removes the entry with key KEY from TABLE. No action is taken and no
  -- error occurs if there is no entry with the given key value, except that
  -- FOUND is set to false.

  procedure Remove_Min (Table: in out Table_Type);
  -- OVERVIEW:
  --   Removes the entry with the smallest key from TABLE.
  -- ERROR:
  --   Raises EMPTY_STRUCTURE_ERROR if TABLE is empty.

  procedure Remove_Max (Table: in out Table_Type);
  -- OVERVIEW:
  --   Removes the entry with the greatest key from TABLE.
  -- ERROR:
  --   Raises EMPTY_STRUCTURE_ERROR if TABLE is empty.

  generic
    with procedure Modify (Key: in String_Type;
                           Value: in out Value_Type) is <>;
  procedure Update_Value_Or_Exception_G (Table: in out Table_Type;
                                         Key: in String_Type);
  -- OVERVIEW:
  --   An entry with key KEY is searched for in TABLE. The associated item is
  -- then passed to procedure MODIFY for modification of its value part.
  -- ERROR:
  --   Raises MISSING_ITEM_ERROR if KEY is not in TABLE.

  generic
    with procedure Modify (Key: in String_Type;
                           Value: in out Value_Type) is <>;
  procedure Update_Value_Or_Status_G (Table: in out Table_Type;
                                      Key: in String_Type;
                                      Found: out Boolean);
  -- OVERVIEW:
  --   An entry with key KEY is searched for in TABLE. The associated item is
  -- then passed to procedure MODIFY for modification of its value part. No
  -- action is taken and no error occurs if there is no entry with the given
  -- key, except that FOUND is set to false.

--/ QUERIES:


  function Size (Table: Table_Type) return Natural;
  -- OVERVIEW:
  --   Returns the number of entries currently in TABLE.

  function Is_Empty (Table: Table_Type) return Boolean;
  -- OVERVIEW:
  --   Returns TRUE if and only if the TABLE is empty.

  function Is_Present (Table: Table_Type; Key: String_Type) return Boolean;
  -- OVERVIEW:
  --   Returns TRUE if and only if an ITEM with key KEY is in TABLE.

  function Value (Table: Table_Type; Key: String_Type) return Value_Type;

  procedure Get_Value(Table: in Table_Type;
                      Key: in String_Type;
                      Value: in out Value_Type);
  -- OVERVIEW:
  --   Gives the VALUE associated with KEY in TABLE.
  -- ERROR:
  --   Raises MISSING_ITEM_ERROR if KEY is not found in TABLE.

  procedure Get_Min_Item (Table: in Table_Type;
                          Key: out String_Type;
                          Last: out Natural;
                          Value: in out Value_Type);
  -- OVERVIEW:
  --   Gives the smallest KEY and the VALUE associated with it in TABLE;
  -- returns in LAST the index value such that KEY(LAST) is the last character
  -- replaced.
  -- ERROR:
  --   Raises EMPTY_STRUCTURE_ERROR if TABLE is empty.
  --   Raises STRING_CONSTRAINT_ERROR if KEY is too short.

  procedure Get_Max_Item (Table: in Table_Type;
                          Key: out String_Type;
                          Last: out Natural;
                          Value: in out Value_Type);
  -- OVERVIEW:
  --   Gives the biggest KEY and the VALUE associated with it in TABLE;
  -- returns in LAST the index value such that KEY(LAST) is the last character
  -- replaced.
  -- ERROR:
  --   Raises EMPTY_STRUCTURE_ERROR if TABLE is empty.
  --   Raises STRING_CONSTRAINT_ERROR if KEY is too short.

  function Min_Key (Table: Table_Type) return String_Type;
  -- OVERVIEW:
  --   Gives the smallest KEY of TABLE.
  -- ERROR:
  --   Raises EMPTY_STRUCTURE_ERROR if TABLE is empty.

  procedure Get_Min_Key (Table: in Table_Type;
                         Key: out String_Type;
                         Last: out Natural);
  -- OVERVIEW:
  --   Gives the smallest KEY of TABLE; returns in LAST the index value such
  -- that KEY(LAST) is the last character replaced.
  -- ERROR:
  --   Raises EMPTY_STRUCTURE_ERROR if TABLE is empty.
  --   Raises STRING_CONSTRAINT_ERROR if KEY is too short.

  function Max_Key (Table: Table_Type) return String_Type;
  -- OVERVIEW:
  --   Gives the biggest KEY of TABLE.
  -- ERROR:
  --   Raises EMPTY_STRUCTURE_ERROR if TABLE is empty.

  procedure Get_Max_Key (Table: in Table_Type;
                         Key: out String_Type;
                         Last: out Natural);
  -- OVERVIEW:
  --   Gives the biggest KEY of TABLE; returns in LAST the index value such
  -- that KEY(LAST) is the last character replaced.
  -- ERROR:
  --   Raises EMPTY_STRUCTURE_ERROR if TABLE is empty.
  --   Raises STRING_CONSTRAINT_ERROR if KEY is too short.

  procedure Get_Less_Item (Table: in Table_Type;
                           Key_In: in String_Type;
                           Key_Out: out String_Type;
                           Last: out Natural;
                           Value: in out Value_Type);
  -- OVERVIEW:
  --   Gives the entry (KEY_OUT, VALUE) having the greatest key value less
  -- than the value of the parameter KEY_IN; returns in LAST the index value
  -- such that KEY_OUT(LAST) is the last character replaced.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such
  -- an entry in the table.
  --   Raises STRING_CONSTRAINT_ERROR if KEY_OUT is too short.

  procedure Get_Less_Or_Equal_Item (Table: in Table_Type;
                                    Key_In: in String_Type;
                                    Key_Out: out String_Type;
                                    Last: out Natural;
                                    Value: in out Value_Type);
  -- OVERVIEW:
  --   Gives the entry (KEY_OUT, VALUE) having the greatest key value less
  -- than or equal to the value of the parameter KEY_IN; returns in LAST the
  -- index value such that KEY_OUT(LAST) is the last character replaced.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such an
  -- entry in the table.
  --   Raises STRING_CONSTRAINT_ERROR if KEY_OUT is too short.

  procedure Get_Greater_Item (Table: in Table_Type;
                              Key_In: in String_Type;
                              Key_Out: out String_Type;
                              Last: out Natural;
                              Value: in out Value_Type);
  -- OVERVIEW:
  --   Gives the entry (KEY_OUT, VALUE) having the smallest key value greater
  -- than the value of the parameter KEY_IN; returns in LAST the index value
  -- such that KEY_OUT(LAST) is the last character replaced.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such an
  -- entry in the table.
  --   Raises STRING_CONSTRAINT_ERROR if KEY_OUT is too short.

  procedure Get_Greater_Or_Equal_Item (Table: in Table_Type;
                                       Key_In: in String_Type;
                                       Key_Out: out String_Type;
                                       Last: out Natural;
                                       Value: in out Value_Type);
  -- OVERVIEW:
  --   Gives the entry (KEY_OUT, VALUE) having the smallest key value greater
  -- than or equal to the value of the parameter KEY_IN; returns in LAST the
  -- index value such that KEY_OUT(LAST) is the last character replaced.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such an
  -- entry in the table.
  --   Raises STRING_CONSTRAINT_ERROR if KEY_OUT is too short.

  function Less_Key (Table: Table_Type; Key: String_Type) return String_Type;
  -- OVERVIEW:
  --   Gives the greatest key value less than the value of the parameter KEY.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such an
  -- entry in the table.

  procedure Get_Less_Key (Table: in Table_Type;
                          Key_In: in String_Type;
                          Key_Out: out String_Type;
                          Last: out Natural);
  -- OVERVIEW:
  --   Gives in KEY_OUT the greatest key value less than the value of the
  -- parameter KEY_IN; returns in LAST the index value such that KEY_OUT(LAST)
  -- is the last character replaced.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such an
  -- entry in the table.
  --   Raises STRING_CONSTRAINT_ERROR if KEY_OUT is too short.

  function Less_Or_Equal_Key (Table: Table_Type; Key: String_Type) return String_Type;
  -- OVERVIEW:
  --   Gives the greatest key value less than or equal to the value of the
  -- parameter KEY.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such an
  -- entry in the table.

  procedure Get_Less_Or_Equal_Key (Table: in Table_Type;
                                   Key_In: in String_Type;
                                   Key_Out: out String_Type;
                                   Last: out Natural);
  -- OVERVIEW:
  --   Gives in KEY_OUT the greatest key value less than or equal to the value
  -- of the parameter KEY_IN; returns in LAST the index value such that
  -- KEY_OUT(LAST) is the last character replaced.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such an
  -- entry in the table.
  --   Raises STRING_CONSTRAINT_ERROR if KEY_OUT is too short.

  function Greater_Key (Table: Table_Type; Key: String_Type) return String_Type;
  -- OVERVIEW:
  --   Gives the smallest key value greater than the value of the parameter
  -- KEY.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such an
  -- entry in the table.

  procedure Get_Greater_Key (Table: in Table_Type;
                             Key_In: in String_Type;
                             Key_Out: out String_Type;
                             Last: out Natural);
  -- OVERVIEW:
  --   Gives in KEY_OUT the smallest key value greater than the value of the
  -- parameter KEY_IN; returns in LAST the index value such that KEY_OUT(LAST)
  -- is the last character replaced.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such an
  -- entry in the table.
  --   Raises STRING_CONSTRAINT_ERROR if KEY_OUT is too short.

  function Greater_Or_Equal_Key (Table: Table_Type; Key: String_Type) return String_Type;
  -- OVERVIEW:
  --   Gives the smallest key value greater than or equal to the
  -- value of the parameter KEY.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such an
  -- entry in the table.

  procedure Get_Greater_Or_Equal_Key (Table: in Table_Type;
                                      Key_In: in String_Type;
                                      Key_Out: out String_Type;
                                      Last: out Natural);
  -- OVERVIEW:
  --   Gives in KEY_OUT the smallest key value greater than or equal to the
  -- value of the parameter KEY_IN; returns in LAST the index value such that
  -- KEY_OUT(LAST) is the last character replaced.
  -- ERROR:
  --   The exception MISSING_ITEM_ERROR is raised if there is not such
  -- an entry in the table.
  --   Raises STRING_CONSTRAINT_ERROR if KEY_OUT is too short.

  --/ SET_OPERATIONS:

  generic package Set_Operations_G is

    procedure Union (Destination: in out Table_Type;
                     Left,
                     Right: in Table_Type);
    -- OVERVIEW:
    --   Union of LEFT and RIGHT. If a key is both in LEFT and RIGHT, the
    -- value is taken from LEFT.

    procedure Intersection (Destination: in out Table_Type;
                            Left,
                            Right: in Table_Type);
    -- OVERVIEW:
    --   Intersection of LEFT and RIGHT. The entries are taken from LEFT.

    procedure Difference (Destination: in out Table_Type;
                          Left,
                          Right: in Table_Type);
    -- OVERVIEW:
    --   Set difference of LEFT and RIGHT. An entry is in the resulting table
    -- if it is in LEFT and if there is no entry with same key in RIGHT.

    procedure Symmetric_Difference (Destination: in out Table_Type;
                                    Left,
                                    Right: in Table_Type);
    -- OVERVIEW:
    --   Symmetric set difference of LEFT and RIGHT. An entry is in the
    -- resulting table if it is in LEFT but there is no entry with same key
    -- in RIGHT or if it is in RIGHT but there is no entry with same key in
    -- LEFT.

    function "=" (Left, Right: Table_Type) return Boolean;
    -- OVERVIEW:
    --   Set equality; the LEFT and RIGHT tables contain entries with same
    -- keys.

    function "<" (Left, Right: Table_Type) return Boolean;
    -- OVERVIEW:
    --   Strict set inclusion; to each entry in the LEFT table an entry with
    -- same key is associated in the RIGHT table, but the two sets are not
    -- identical.

    function "<=" (Left, Right: Table_Type) return Boolean;
    -- OVERVIEW:
    --   Set inclusion; to each entry in the LEFT table an entry with same
    -- key is associated in the RIGHT table.

    function ">" (Left, Right: Table_Type) return Boolean;
    -- OVERVIEW:
    --   Strict set inclusion; to each entry in the RIGHT table an entry with
    -- same key is associated in the LEFT table, but the two sets are not
    -- identical.

    function ">=" (Left, Right: Table_Type) return Boolean;
    -- OVERVIEW:
    --   Set inclusion; to each entry in the RIGHT table an entry with same
    -- key is associated in the LEFT table.

  end Set_Operations_G;

--/ ITERATORS:

  generic
    with procedure Action (Key: in String_Type;
                           Value: in Value_Type;
                           Order_Number: in Positive;
                           Continue: in out Boolean) is <>;
  procedure Traverse_Asc_G (Table: in Table_Type);
  -- OVERVIEW:
  --   The entries in TABLE are visited in ascending order of their key
  -- values. Procedure ACTION is applied on each entry within TABLE.
  --   ORDER_NUMBER gives the position of the visited entry in order of
  -- traversal. The boolean CONTINUE specifies if you want to proceed to the
  -- next entry or if you want to stop traversing. As long as you do not
  -- modify its value within ACTION, its value remains TRUE.
  -- REQUIREMENT:
  --   For your actual procedure  ACTION, you must not use a procedure
  -- which modifies the traversed table.


  generic
    with procedure Action (Key: in String_Type;
                           Value: in Value_Type;
                           Order_Number: in Positive;
                           Continue: in out Boolean) is <>;
  procedure Traverse_Desc_G (Table: in Table_Type);
  -- OVERVIEW:
  --   The entries in TABLE are visited in descending order of their key
  -- values. Procedure ACTION is applied on each entry within TABLE.
  --   ORDER_NUMBER gives the position of the visited entry in order of
  -- traversal. The boolean CONTINUE specifies if you want to proceed to the
  -- next entry or if you want to stop traversing. As long as you do not
  -- modify its value within ACTION, its value remains TRUE.
  -- REQUIREMENT:
  --   For your actual procedure  ACTION, you must not use a procedure
  -- which modifies the traversed table.

  generic
    with procedure Modify (Key: in String_Type;
                           Value: in out Value_Type;
                           Order_Number: in Positive;
                           Continue: in out Boolean) is <>;
  procedure Traverse_Asc_And_Update_Value_G (Table: in out Table_Type);
  -- OVERVIEW:
  --   The entries in TABLE are visited in ascending order of their key
  -- values. For each visited entry, procedure MODIFY is called. The value of
  -- the current entry is then replaced by the new value.
  --   ORDER_NUMBER gives the position of the visited entry in order of
  -- traversal. The boolean CONTINUE specifies if you want to proceed to the
  -- next entry or if you want to stop traversing. As long as you do not
  -- modify its value within MODIFY, its value remains TRUE.
  -- REQUIREMENT:
  --   For your actual procedure MODIFY, you must not use a procedure which
  -- modifies the traversed table.

  generic
    with procedure Modify (Key: in String_Type;
                           Value: in out Value_Type;
                           Order_Number: in Positive;
                           Continue: in out Boolean) is <>;
  procedure Traverse_Desc_And_Update_Value_G (Table: in out Table_Type);
  -- OVERVIEW:
  --   The entries in TABLE are visited in descending order of their key
  -- values. For each visited entry, procedure MODIFY is called. The item
  -- value of the current entry is then replaced by the new value.
  --   ORDER_NUMBER gives the position of the visited entry in order of
  -- traversal. The boolean CONTINUE specifies if you want to proceed to the
  -- next entry or if you want to stop traversing. As long as you do not
  -- modify its value within MODIFY, its value remains TRUE.
  -- REQUIREMENT:
  --   For your actual procedure MODIFY, you must not use a procedure which
  -- modifies the traversed table.

  generic
    with procedure Action (Key: in String_Type;
                           Value: in Value_Type;
                           Order_Number: in Positive;
                           Continue: in out Boolean) is <>;
  procedure Disorder_Traverse_G (Table: in Table_Type);
  -- OVERVIEW:
  --   The entries in TABLE are visited in disorder of their key values.
  -- procedure ACTION is applied on each entry within TABLE.
  --   ORDER_NUMBER gives the position of the visited entry in order of
  -- traversal. The boolean CONTINUE specifies if you want to proceed to the
  -- next entry or if you want to stop traversing. As long as you do not
  -- modify its value within ACTION, its value remains TRUE.
  --   Traversal by DISORDER_TRAVERSE_G is faster than by TRAVERSE_ASC_G or
  -- TRAVERSE_DESC_G. Moreover, use of the generic procedure
  -- DISORDER_TRAVERSE_G is recommended for saving a table in a backstore
  -- (file or linear list) because recovery will be efficient.
  -- REQUIREMENT:
  --   For your actual procedure  ACTION, you must not use a procedure
  -- which modifies the traversed table.

  generic
    with procedure Modify (Key: in String_Type;
                           Value: in out Value_Type;
                           Order_Number: in Positive;
                           Continue: in out Boolean) is <>;
  procedure Disorder_Traverse_And_Update_Value_G (Table: in out Table_Type);
  -- OVERVIEW:
  --   The entries in TABLE are visited in disorder of their key values.
  -- procedure MODIFY is applied on each entry within TABLE. The item
  -- value of the current entry is then replaced by the new value.
  --   ORDER_NUMBER gives the position of the visited entry in order of
  -- traversal. The boolean CONTINUE specifies if you want to proceed to the
  -- next entry or if you want to stop traversing. As long as you do not
  -- modify its value within MODIFY, its value remains TRUE.
  --   Traversal by DISORDER_TRAVERSE_G is faster than by TRAVERSE_ASC_G or
  -- TRAVERSE_DESC_G.
  -- REQUIREMENT:
  --   For your actual procedure  MODIFY, you must not use a procedure
  -- which modifies the traversed table.

--/ HEAP MANAGEMENT:

  procedure Destroy (Table: in out Table_Type);
  -- OVERVIEW:
  --   Empties the TABLE and returns space to the free list.

  procedure Release_Free_List;
  -- OVERVIEW:
  --   Releases all items from the free list giving their space back to the
  -- system.


  procedure Set_Max_Free_List_Size (Max_Free_List_Size: in Natural);
  -- OVERVIEW:
  --   Sets the maximum length of the internal free list which is 0 by default.
  -- If parameter MAX_FREE_LIST_SIZE is smaller than the current size
  -- of the list, the items in excess are returned to the system.


  function Free_List_Size return Natural;
  -- OVERVIEW:
  --   Returns the actual length of the internal free list.

private
  type Access_String_Type is access String_Type;
  function Less (Left, Right: Access_String_Type) return Boolean;
  function Equals (Left, Right: Access_String_Type) return Boolean;
  procedure Assign (Destination: in out Access_String_Type;
                    Source: in Access_String_Type);
  procedure Destroy (Access_String: in out Access_String_Type);

  package Local_Package is
    new Table_Of_Dynamic_Keys_And_Dynamic_Values_G (Access_String_Type,
                                                    Less,
                                                    Equals,
                                                    Assign,
                                                    Destroy,
                                                    Value_Type,
                                                    Assign,
                                                    Destroy);
  type Table_Type is new Local_Package.Table_Type;
end Table_Of_Strings_And_Dynamic_Values_G;