BIND 10 #2831: define and implement MemorySegmentMapped

[BIND 10 Development]

#2831: define and implement MemorySegmentMapped
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            Reporter:  jinmei        |                        Owner:
                Type:  task          |  jinmei
            Priority:  medium        |                       Status:
           Component:  data source   |  accepted
            Keywords:                |                    Milestone:
           Sensitive:  0             |  Sprint-20130319
         Sub-Project:  DNS           |                   Resolution:
Estimated Difficulty:  5             |                 CVSS Scoring:
         Total Hours:  0             |              Defect Severity:  N/A
                                     |  Feature Depending on Ticket:
                                     |  shared memory data source
                                     |          Add Hours to Ticket:  0
                                     |                    Internal?:  0
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Comment (by jinmei):

 trac2831 is ready for review.

 Given the underlying boost classes, this implementation should generally
 be a straightforward wrapper.

 One change from the original ticket description is the shrinkToFit()
 method.  After considering more details of how to use it, I now
 suspect it doesn't have to be virtual (so it can be used at the base
 class interface).  So I defined it as a local (non virtual) method
 for `MemorySegmentMapped`.

 I don't think we need a changelog entry for this task.  It's basically
 intended to be internal only, and it's mostly hidden even internally
 as the base class interface would generally be used.

-- 
Ticket URL: <http://bind10.isc.org/ticket/2831#comment:10>
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