On Apr 22, 1:43 pm, Brendan <catph...@[EMAIL PROTECTED]
> wrote:
> At a prior job, people were using std::string to hold arbitrary binary
> data, as opposed to vector<char>. I've seen a few people in this group
> poopoo that notion, and I'd like to find out what they think the
> pitfalls, if any, of using string to hold binary data are. I ask,
> because otherwise the code base was pretty high quality, and string
> does offer a number of extra search based member functions that vector
> does not.
>
> Additionally, is there any strong reason to use unsigned char as
> opposed to char to hold binary data where the high order bit might be
> set? Again, in practice I've mostly seen char used.
>
> Thanks
There is nothing wrong with using std::string to hold binary data.
There is nothing in std::string that assumes any particular text
encoding, ispo facto std::string only holds binary data.
There is a compelling reason to use unsigned -- when doing
comparisions, many processors must "sign extend" char data to
something the size of an int. On intel this is the movsx instruction.
When unsigned, the mov is "zero extend" (Intel movzx). movzx is
typically one cycle less than movsx. If you are not doing compares,
tests, or such on the binary data then it doesnt make a difference.
Also note that basic_string<unsigned char> will not play nice with
cout.
Lance
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