+namespace llvm {
+namespace sys {
+namespace path {
+
+const_iterator begin(StringRef path) {
+ const_iterator i;
+ i.Path = path;
+ i.Component = find_first_component(path);
+ i.Position = 0;
+ return i;
+}
+
+const_iterator end(StringRef path) {
+ const_iterator i;
+ i.Path = path;
+ i.Position = path.size();
+ return i;
+}
+
+const_iterator &const_iterator::operator++() {
+ assert(Position < Path.size() && "Tried to increment past end!");
+
+ // Increment Position to past the current component
+ Position += Component.size();
+
+ // Check for end.
+ if (Position == Path.size()) {
+ Component = StringRef();
+ return *this;
+ }
+
+ // Both POSIX and Windows treat paths that begin with exactly two separators
+ // specially.
+ bool was_net = Component.size() > 2 &&
+ is_separator(Component[0]) &&
+ Component[1] == Component[0] &&
+ !is_separator(Component[2]);
+
+ // Handle separators.
+ if (is_separator(Path[Position])) {
+ // Root dir.
+ if (was_net
+#ifdef LLVM_ON_WIN32
+ // c:/
+ || Component.endswith(":")
+#endif
+ ) {
+ Component = Path.substr(Position, 1);
+ return *this;
+ }
+
+ // Skip extra separators.
+ while (Position != Path.size() &&
+ is_separator(Path[Position])) {
+ ++Position;
+ }
+
+ // Treat trailing '/' as a '.'.
+ if (Position == Path.size()) {
+ --Position;
+ Component = ".";
+ return *this;
+ }
+ }
+
+ // Find next component.
+ size_t end_pos = Path.find_first_of(separators, Position);
+ Component = Path.slice(Position, end_pos);
+
+ return *this;
+}
+
+bool const_iterator::operator==(const const_iterator &RHS) const {
+ return Path.begin() == RHS.Path.begin() && Position == RHS.Position;
+}
+
+ptrdiff_t const_iterator::operator-(const const_iterator &RHS) const {
+ return Position - RHS.Position;
+}
+
+reverse_iterator rbegin(StringRef Path) {
+ reverse_iterator I;
+ I.Path = Path;
+ I.Position = Path.size();
+ return ++I;
+}
+
+reverse_iterator rend(StringRef Path) {
+ reverse_iterator I;
+ I.Path = Path;
+ I.Component = Path.substr(0, 0);
+ I.Position = 0;
+ return I;
+}
+
+reverse_iterator &reverse_iterator::operator++() {
+ // If we're at the end and the previous char was a '/', return '.' unless
+ // we are the root path.
+ size_t root_dir_pos = root_dir_start(Path);
+ if (Position == Path.size() &&
+ Path.size() > root_dir_pos + 1 &&
+ is_separator(Path[Position - 1])) {
+ --Position;
+ Component = ".";
+ return *this;
+ }
+
+ // Skip separators unless it's the root directory.
+ size_t end_pos = Position;
+
+ while(end_pos > 0 &&
+ (end_pos - 1) != root_dir_pos &&
+ is_separator(Path[end_pos - 1]))
+ --end_pos;
+
+ // Find next separator.
+ size_t start_pos = filename_pos(Path.substr(0, end_pos));
+ Component = Path.slice(start_pos, end_pos);
+ Position = start_pos;
+ return *this;
+}
+
+bool reverse_iterator::operator==(const reverse_iterator &RHS) const {
+ return Path.begin() == RHS.Path.begin() && Component == RHS.Component &&
+ Position == RHS.Position;
+}
+
+const StringRef root_path(StringRef path) {
+ const_iterator b = begin(path),
+ pos = b,
+ e = end(path);
+ if (b != e) {
+ bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
+ bool has_drive =
+#ifdef LLVM_ON_WIN32
+ b->endswith(":");
+#else
+ false;
+#endif
+
+ if (has_net || has_drive) {
+ if ((++pos != e) && is_separator((*pos)[0])) {
+ // {C:/,//net/}, so get the first two components.
+ return path.substr(0, b->size() + pos->size());
+ } else {
+ // just {C:,//net}, return the first component.
+ return *b;
+ }
+ }
+
+ // POSIX style root directory.
+ if (is_separator((*b)[0])) {
+ return *b;
+ }
+ }
+
+ return StringRef();
+}
+
+const StringRef root_name(StringRef path) {
+ const_iterator b = begin(path),
+ e = end(path);
+ if (b != e) {
+ bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
+ bool has_drive =
+#ifdef LLVM_ON_WIN32
+ b->endswith(":");
+#else
+ false;
+#endif
+
+ if (has_net || has_drive) {
+ // just {C:,//net}, return the first component.
+ return *b;
+ }
+ }
+
+ // No path or no name.
+ return StringRef();
+}
+
+const StringRef root_directory(StringRef path) {
+ const_iterator b = begin(path),
+ pos = b,
+ e = end(path);
+ if (b != e) {
+ bool has_net = b->size() > 2 && is_separator((*b)[0]) && (*b)[1] == (*b)[0];
+ bool has_drive =
+#ifdef LLVM_ON_WIN32
+ b->endswith(":");
+#else
+ false;
+#endif
+
+ if ((has_net || has_drive) &&
+ // {C:,//net}, skip to the next component.
+ (++pos != e) && is_separator((*pos)[0])) {
+ return *pos;
+ }
+
+ // POSIX style root directory.
+ if (!has_net && is_separator((*b)[0])) {
+ return *b;
+ }
+ }
+
+ // No path or no root.
+ return StringRef();
+}
+
+const StringRef relative_path(StringRef path) {
+ StringRef root = root_path(path);
+ return path.substr(root.size());
+}
+
+void append(SmallVectorImpl<char> &path, const Twine &a,
+ const Twine &b,
+ const Twine &c,
+ const Twine &d) {
+ SmallString<32> a_storage;
+ SmallString<32> b_storage;
+ SmallString<32> c_storage;
+ SmallString<32> d_storage;
+
+ SmallVector<StringRef, 4> components;
+ if (!a.isTriviallyEmpty()) components.push_back(a.toStringRef(a_storage));
+ if (!b.isTriviallyEmpty()) components.push_back(b.toStringRef(b_storage));
+ if (!c.isTriviallyEmpty()) components.push_back(c.toStringRef(c_storage));
+ if (!d.isTriviallyEmpty()) components.push_back(d.toStringRef(d_storage));
+
+ for (SmallVectorImpl<StringRef>::const_iterator i = components.begin(),
+ e = components.end();
+ i != e; ++i) {
+ bool path_has_sep = !path.empty() && is_separator(path[path.size() - 1]);
+ bool component_has_sep = !i->empty() && is_separator((*i)[0]);
+ bool is_root_name = has_root_name(*i);
+
+ if (path_has_sep) {
+ // Strip separators from beginning of component.
+ size_t loc = i->find_first_not_of(separators);
+ StringRef c = i->substr(loc);
+
+ // Append it.
+ path.append(c.begin(), c.end());
+ continue;
+ }
+
+ if (!component_has_sep && !(path.empty() || is_root_name)) {
+ // Add a separator.
+ path.push_back(preferred_separator);
+ }
+
+ path.append(i->begin(), i->end());
+ }
+}
+
+void append(SmallVectorImpl<char> &path,
+ const_iterator begin, const_iterator end) {
+ for (; begin != end; ++begin)
+ path::append(path, *begin);
+}
+
+const StringRef parent_path(StringRef path) {
+ size_t end_pos = parent_path_end(path);
+ if (end_pos == StringRef::npos)
+ return StringRef();
+ else
+ return path.substr(0, end_pos);
+}
+
+void remove_filename(SmallVectorImpl<char> &path) {
+ size_t end_pos = parent_path_end(StringRef(path.begin(), path.size()));
+ if (end_pos != StringRef::npos)
+ path.set_size(end_pos);
+}
+
+void replace_extension(SmallVectorImpl<char> &path, const Twine &extension) {
+ StringRef p(path.begin(), path.size());
+ SmallString<32> ext_storage;
+ StringRef ext = extension.toStringRef(ext_storage);
+
+ // Erase existing extension.
+ size_t pos = p.find_last_of('.');
+ if (pos != StringRef::npos && pos >= filename_pos(p))
+ path.set_size(pos);
+
+ // Append '.' if needed.
+ if (ext.size() > 0 && ext[0] != '.')
+ path.push_back('.');
+
+ // Append extension.
+ path.append(ext.begin(), ext.end());
+}
+
+void native(const Twine &path, SmallVectorImpl<char> &result) {
+ assert((!path.isSingleStringRef() ||
+ path.getSingleStringRef().data() != result.data()) &&
+ "path and result are not allowed to overlap!");
+ // Clear result.
+ result.clear();
+ path.toVector(result);
+ native(result);
+}