[llvm-commits] PATCH: Additional SmallString methods

[Talin]

On Fri, Jan 20, 2012 at 12:24 PM, David Blaikie <dblaikie at gmail.com> wrote:

> If we just made these free functions taking StringRef would that be
> easier/more reusable? (& then relying on the conversion operator Jim
> mentioned)
>
> I'd say it's a preferable design anyway (see the GoTW post on the
> problems of the monolithic design of std::basic_string
> http://www.gotw.ca/gotw/084.htm )
>

This is primarily a stylistic argument on which I have no opinion. I don't
think it makes sense to re-engineer StringRef to fit with a different
convention for how string operations are done, because the benefit isn't
worth the cost of migration. I'm just attempting to make all of the string
classes within LLVM more consistent with each other and with standard STL.
(I want to do the same with other collections as well.)


> On Thu, Jan 19, 2012 at 11:42 PM, Talin <viridia at gmail.com> wrote:
> > This patch adds many convenience methods to class SmallString:
> >
> > void assign(unsigned NumElts, char Elt);
> > void assign(in_iter S, in_iter E);
> > void assign(StringRef RHS);
> > void assign(const SmallVectorImpl<char> &RHS);
> > void append(in_iter S, in_iter E);
> > void append(StringRef RHS);
> > void append(const SmallVectorImpl<char> &RHS);
> > bool equals(StringRef RHS) const;
> > bool equals_lower(StringRef RHS) const;
> > int compare(StringRef RHS) const;
> > int compare_lower(StringRef RHS) const;
> > int compare_numeric(StringRef RHS) const;
> > bool startswith(StringRef Prefix) const;
> > bool endswith(StringRef Suffix) const;
> > size_t find(char C, size_t From = 0) const;
> > size_t find(StringRef Str, size_t From = 0) const;
> > size_t rfind(char C, size_t From = StringRef::npos) const;
> > size_t rfind(StringRef Str) const;
> > size_t find_first_of(char C, size_t From = 0) const;
> > size_t find_first_of(StringRef Chars, size_t From = 0) const;
> > size_t find_first_not_of(char C, size_t From = 0) const;
> > size_t find_first_not_of(StringRef Chars, size_t From = 0) const;
> > size_t find_last_of(char C, size_t From = StringRef::npos) const;
> > size_t find_last_of(StringRef Chars, size_t From = StringRef::npos)
> const;
> > size_t count(char C) const;
> > size_t count(StringRef Str) const;
> > StringRef substr(size_t Start, size_t N = StringRef::npos) const;
> > StringRef slice(size_t Start, size_t End) const;
> >
> > Most of the methods are taken directly from StringRef (find_x, compare_x,
> > substr, and so on). My motivation for adding these methods is that often
> I
> > find myself working with a SmallString instead of a StringRef, and it
> would
> > be nice to call substr() for example directly without having to convert
> to a
> > StringRef. Internally, of course, the methods simply convert the
> SmallString
> > to a StringRef (which is extremely cheap), and then call the
> corresponding
> > StringRef method. Doing it this way minimizes template expansion, since
> > StringRef is a non-template class.
> >
> > The 'assign' and 'append' methods are taken from standard STL, with
> > additional overloads that are convenient for strings. For example,
> assign()
> > now allows assigning to a SmallString from an iterator pair, which was
> not
> > supported before.
> >
> > (Note: I thought about adding support for assign/append/construct from an
> > ArrayRef<char>, but that would add an additional include file
> dependency.)
> >
> > This patch also includes many additions to the unit tests for
> SmallString,
> > as well as some minor typographical cleanups in the comments in
> > SmallString.h.
> >
> > --
> > -- Talin
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> >
>



-- 
-- Talin
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