Re: [Libvir] [PATCH] Enhance virBuffer code

Daniel Veillard <veillard(a)redhat.com&gt; wrote: > On Thu, Dec 13, 2007 at 11:21:31PM +0100, Jim Meyering wrote: >> "Richard W.M. Jones" <rjones(a)redhat.com&gt; wrote: >> ... >> > + * virBufferURIEncodeString: >> > + * @buf: the buffer to append to >> > + * @str: the string argument which will be URI-encoded >> > + * >> > + * Append the string to the buffer. The string will be URI-encoded >> > + * during the append (ie any non alpha-numeric characters are replaced >> > + * with '%xx' hex sequences). >> > + * >> > + * Returns 0 successful, -1 in case of internal or API error. >> > + */ >> > +int >> > +virBufferURIEncodeString (virBufferPtr buf, const char *str) >> > +{ >> > + int grow_size = 0; >> > + const char *p; >> > + unsigned char uc; >> > + const char *hex = "0123456789abcdef"; >> > + >> > + for (p = str; *p; ++p) { >> > + /* Want to leave only strict 7 bit ASCII alphanumerics ... */ >> > + if ((*p >= '0' && *p <= '9') || >> > + (*p >= 'a' && *p <= 'z') || >> > + (*p >= 'A' && *p <= 'Z')) >> ... >> > + for (p = str; *p; ++p) { >> > + if ((*p >= '0' && *p <= '9') || >> > + (*p >= 'a' && *p <= 'z') || >> > + (*p >= 'A' && *p <= 'Z')) >> >> Hi Rich, >> >> What do you think of using this? >> >> isascii (*p) && isalnum (*p) > > I have learned to be very cautious of the is* macros because they > tend to be local dependant whichis usually really not what you would > like or expect. In that case this may work, but explicit ranges > are 100% clear about what you intend to accept or not, that's why I > usually prefer them. You're right that we shouldn't use isalnum here. However, we shouldn't use inequality comparisons, either. While 0 <= c <= 9 is guaranteed to be ok for the digits, the a..z and A..Z ranges need not be contiguous, i.e., with EBCDIC: