[jira] [Resolved] (QPID-4553) C++ qpid::types::Variant::uint8_t not treated as integer during string conversion

["Chuck Rolke (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/QPID-4553?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Chuck Rolke resolved QPID-4553.
-------------------------------

       Resolution: Won't Fix
    Fix Version/s: 0.21

Changing uint8_t to behave as an integer would leave the interface with no way to do char conversions. C++ Messaging had to make some choices when mapping into the C language. This is issue is just a side effect of that mapping.
                
> C++ qpid::types::Variant::uint8_t not treated as integer during string conversion
> ---------------------------------------------------------------------------------
>
>                 Key: QPID-4553
>                 URL: https://issues.apache.org/jira/browse/QPID-4553
>             Project: Qpid
>          Issue Type: Bug
>          Components: C++ Broker
>    Affects Versions: 0.21
>         Environment: Linux/windows broker/client Messaging
>            Reporter: Chuck Rolke
>             Fix For: 0.21
>
>
> There are unexpected conversion side effects when a uint8_t is created from a string. I expected the string value to be decoded into a binary value 0..255, the same as I expect for uint16_t, uint32_t, and uint64_t and their expected values. Instead uint8_t receives the first character of a one-character string as if there's an implicit string-to-single-character conversion. This behavior is not a regression.
> Am I mistaken expecting a 0..255 value from the .asUint8() function? 
> The underlying cause is Boost being invoked through a template that works one way for three of the four cases and a different way for the uint8_t case. I'd like to get rid of that and replace it with a single, common string decode into a 64-bit integer. Then for the smaller subtypes mask the value down to the size of the respective type and throw if there's a range error.
> Here's a test where I'm looking at the recent "-0" conversion fix. In all cases I expect the value to be a binary zero. In the uint8_t case it is not. The only case where the conversion does not throw returns a value of 48 '0'.
> {code}
> void testZeroValueAs(const Variant theValue)
> {
>     std::string phase;
>     try
>     {
>         phase = "64bit - ";
>         uint64_t myu64 = theValue.asUint64();
>         if (myu64 != 0) 
>             std::cout << "Failed at uint64 : "  
>                       << myu64 << std::endl;
>         phase = "32bit - ";
>         uint32_t myu32 = theValue.asUint32();
>         if (myu32 != 0) 
>             std::cout << "Failed at uint32 : "  
>                       << myu32 << std::endl;
>         phase = "16bit - ";
>         uint16_t myu16 = theValue.asUint16();
>         if (myu16 != 0) 
>             std::cout << "Failed at uint16 : "  
>                       << myu16 << std::endl;
>         phase = "8bit - ";
>         uint8_t myu8 = theValue.asUint8();
>         if (myu8 != 0) 
>             std::cout << "Failed at uint8 : " 
>                       << myu8 << std::endl;
>     } catch (const std::exception& error) {
>         std::cout << "Exception in phase " 
>                   << phase 
>                   << error.what() 
>                   << std::endl;
>     }
> }
>     Variant value;
>     value = "0";
>     testZeroValueAs(value);
>     value = "00";
>     testZeroValueAs(value);
>     value = "-00";
>     testZeroValueAs(value);
> {code}
> at run time this example produces:
> {code}
> Failed at uint8 : 0
> Exception in phase 8bit - invalid conversion: Cannot convert 00 (..\..\qpid\cpp\src\qpid\types\Variant.cpp:126)
> Exception in phase 8bit - invalid conversion: Cannot convert -00 (..\..\qpid\cpp\src\qpid\types\Variant.cpp:126)
> {code}

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