+static char ascii_tolower(char x) {
+ if (x >= 'A' && x <= 'Z')
+ return x - 'A' + 'a';
+ return x;
+}
+
+static char ascii_toupper(char x) {
+ if (x >= 'a' && x <= 'z')
+ return x - 'a' + 'A';
+ return x;
+}
+
+static bool ascii_isdigit(char x) {
+ return x >= '0' && x <= '9';
+}
+
+// strncasecmp() is not available on non-POSIX systems, so define an
+// alternative function here.
+static int ascii_strncasecmp(const char *LHS, const char *RHS, size_t Length) {
+ for (size_t I = 0; I < Length; ++I) {
+ unsigned char LHC = ascii_tolower(LHS[I]);
+ unsigned char RHC = ascii_tolower(RHS[I]);
+ if (LHC != RHC)
+ return LHC < RHC ? -1 : 1;
+ }
+ return 0;
+}
+
+/// compare_lower - Compare strings, ignoring case.
+int StringRef::compare_lower(StringRef RHS) const {
+ if (int Res = ascii_strncasecmp(Data, RHS.Data, std::min(Length, RHS.Length)))
+ return Res;
+ if (Length == RHS.Length)
+ return 0;
+ return Length < RHS.Length ? -1 : 1;
+}
+
+/// Check if this string starts with the given \p Prefix, ignoring case.
+bool StringRef::startswith_lower(StringRef Prefix) const {
+ return Length >= Prefix.Length &&
+ ascii_strncasecmp(Data, Prefix.Data, Prefix.Length) == 0;
+}
+
+/// Check if this string ends with the given \p Suffix, ignoring case.
+bool StringRef::endswith_lower(StringRef Suffix) const {
+ return Length >= Suffix.Length &&
+ ascii_strncasecmp(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
+}
+
+/// compare_numeric - Compare strings, handle embedded numbers.
+int StringRef::compare_numeric(StringRef RHS) const {
+ for (size_t I = 0, E = std::min(Length, RHS.Length); I != E; ++I) {
+ // Check for sequences of digits.
+ if (ascii_isdigit(Data[I]) && ascii_isdigit(RHS.Data[I])) {
+ // The longer sequence of numbers is considered larger.
+ // This doesn't really handle prefixed zeros well.
+ size_t J;
+ for (J = I + 1; J != E + 1; ++J) {
+ bool ld = J < Length && ascii_isdigit(Data[J]);
+ bool rd = J < RHS.Length && ascii_isdigit(RHS.Data[J]);
+ if (ld != rd)
+ return rd ? -1 : 1;
+ if (!rd)
+ break;
+ }
+ // The two number sequences have the same length (J-I), just memcmp them.
+ if (int Res = compareMemory(Data + I, RHS.Data + I, J - I))
+ return Res < 0 ? -1 : 1;
+ // Identical number sequences, continue search after the numbers.
+ I = J - 1;
+ continue;
+ }
+ if (Data[I] != RHS.Data[I])
+ return (unsigned char)Data[I] < (unsigned char)RHS.Data[I] ? -1 : 1;
+ }
+ if (Length == RHS.Length)
+ return 0;
+ return Length < RHS.Length ? -1 : 1;
+}
+
+// Compute the edit distance between the two given strings.
+unsigned StringRef::edit_distance(llvm::StringRef Other,
+ bool AllowReplacements,
+ unsigned MaxEditDistance) const {
+ return llvm::ComputeEditDistance(
+ makeArrayRef(data(), size()),
+ makeArrayRef(Other.data(), Other.size()),
+ AllowReplacements, MaxEditDistance);
+}
+
+//===----------------------------------------------------------------------===//
+// String Operations
+//===----------------------------------------------------------------------===//
+
+std::string StringRef::lower() const {
+ std::string Result(size(), char());
+ for (size_type i = 0, e = size(); i != e; ++i) {
+ Result[i] = ascii_tolower(Data[i]);
+ }
+ return Result;
+}
+
+std::string StringRef::upper() const {
+ std::string Result(size(), char());
+ for (size_type i = 0, e = size(); i != e; ++i) {
+ Result[i] = ascii_toupper(Data[i]);
+ }
+ return Result;
+}
+