Re: Pascal vs C style string ?

Strings that are prefixed by a length are more tolerant of some
styles of programming, since finding the length of the string
is a fast operation, especially if the compiler knows about the
string representation and can compile the expression length(string)
into a simple load instruction.


I have too often seen careless C code like


for (i = 0; i < strlen(very_long_string); ++i) {
        do_something_with(very_long_string[i]);
}


For those who do not know C, this loop unnecessarily scans through
the whole very_long_string at every iteration. It would be quite OK
if the length-prefixed representation were used. In theory, a smart
compiler could fix this, at least in some cases. I wonder if any
actual C compiler does it?


Erkki Ruohtula / Nokia Telecommunications Oy
eru@tele.nokia.fi / P.O. Box 33 SF-02601 Espoo, Finland
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