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From "Alan Conway (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (QPID-6470) FieldValue::getFloatingPointValue() converts endian each time it is called
Date Fri, 03 Apr 2015 05:42:53 GMT

    [ https://issues.apache.org/jira/browse/QPID-6470?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14394093#comment-14394093
] 

Alan Conway commented on QPID-6470:
-----------------------------------


Yes. ConvertIfRrequired(p, n) swaps the bytes p..p+n in place and returns pointer p. The current
code swaps the encoded octets, then copies that to the return value. That works the first
time, but the second time in octets are backwards so you get a bogus result. It alternates
between giving the right answer and the swapped answer. What the patch does is copy the octets
to the return value, then swap the return value so the octets are unchanged.

I have this fix, I added some unit tests and discovered some more issues (incorrect conversions
from float to int and some missing get/set functions) The type info is somewhat in the wrong
place. A FixedWidthValue only knows its width, not its type, so it can't implement convertibleToInt()
correctly (the current implementation returns true, which is wrong if the value contains a
float and results in an invalid byte-copy conversion giving a nonsense value.) I'm trying
to decide the least disturbing way to get the type info to the convertibleTo tests, or maybe
introduce subclasses for FixedWidthFloatValue and FixedWidthIntValue.

> FieldValue::getFloatingPointValue() converts endian each time it is called
> --------------------------------------------------------------------------
>
>                 Key: QPID-6470
>                 URL: https://issues.apache.org/jira/browse/QPID-6470
>             Project: Qpid
>          Issue Type: Bug
>          Components: C++ Broker, C++ Client, C++ Clustering
>    Affects Versions: 0.32, 0.33
>         Environment: Windows 7
>            Reporter: Pavel Pokutnev
>            Assignee: Alan Conway
>            Priority: Critical
>              Labels: easyfix, patch
>   Original Estimate: 0.5h
>  Remaining Estimate: 0.5h
>
> When calling getFloatingPointValue multiple times, the octets are endian-converted each
time.
> Actually we need to make a copy first and then call convertIfRequired().



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