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A.18.19 The Generic Package Containers.Bounded_Vectors

The language-defined generic package Containers.Bounded_Vectors provides a private type Vector and a set of operations. It provides the same operations as the package Containers.Vectors (see A.18.2), with the difference that the maximum storage is bounded.

Static Semantics

The declaration of the generic library package Containers.Bounded_Vectors has the same contents and semantics as Containers.Vectors except:
The pragma Preelaborate is replaced with pragma Pure.
The type Vector is declared with a discriminant that specifies the capacity: 
  type Vector (Capacity : Count_Type) is tagged private;
The type Vector needs finalization if and only if type Element_Type needs finalization.
In function Copy, if the Capacity parameter is equal to or greater than the length of Source, the vector capacity exactly equals the value of the Capacity parameter.
The description of Reserve_Capacity is replaced with: 
If the specified Capacity is larger than the capacity of Container, then Reserve_Capacity propagates Capacity_Error. Otherwise, the operation has no effect. 

Bounded (Run-Time) Errors

 It is a bounded error to assign from a bounded vector object while tampering with elements or cursors of that object is prohibited. Either Program_Error is raised by the assignment, execution proceeds with the target object prohibiting tampering with elements or cursors, or execution proceeds normally. 

Erroneous Execution

 When a bounded vector object V is finalized, if tampering with cursors is prohibited for V other than due to an assignment from another vector, then execution is erroneous.

Implementation Requirements

 For each instance of Containers.Vectors and each instance of Containers.Bounded_Vectors, if the two instances meet the following conditions, then the output generated by the Vector'Output or Vector'Write subprograms of either instance shall be readable by the Vector'Input or Vector'Read of the other instance, respectively:
the Element_Type parameters of the two instances are statically matching subtypes of the same type; and
the output generated by Element_Type'Output or Element_Type'Write is readable by Element_Type'Input or Element_Type'Read, respectively (where Element_Type denotes the type of the two actual Element_Type parameters); and
the preceding two conditions also hold for the Index_Type parameters of the instances. 

Implementation Advice

 Bounded vector objects should be implemented without implicit pointers or dynamic allocation. 
 The implementation advice for procedure Move to minimize copying does not apply. 

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