Add llvm::hexDigitValue to convert single characters to hex.

[oota-llvm.git] / include / llvm / ADT / StringExtras.h

diff --git a/include/llvm/ADT/StringExtras.h b/include/llvm/ADT/StringExtras.h
index 36df5acadb4d8631fbbba96a2112b6ad9a3a1a54..d2887c5c2c56f9a18363845983c4bbec517bbedb 100644 (file)
--- a/include/llvm/ADT/StringExtras.h
+++ b/include/llvm/ADT/StringExtras.h
@@ -14,19 +14,30 @@
 #ifndef LLVM_ADT_STRINGEXTRAS_H
 #define LLVM_ADT_STRINGEXTRAS_H
 
-#include "llvm/Support/DataTypes.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/DataTypes.h"
 
 namespace llvm {
 template<typename T> class SmallVectorImpl;
 
 /// hexdigit - Return the hexadecimal character for the
-/// given number \arg X (which should be less than 16).
+/// given number \p X (which should be less than 16).
 static inline char hexdigit(unsigned X, bool LowerCase = false) {
   const char HexChar = LowerCase ? 'a' : 'A';
   return X < 10 ? '0' + X : HexChar + X - 10;
 }
 
+/// Interpret the given character \p C as a hexadecimal digit and return its
+/// value.
+///
+/// If \p C is not a valid hex digit, -1U is returned.
+static inline unsigned hexDigitValue(char C) {
+  if (C >= '0' && C <= '9') return C-'0';
+  if (C >= 'a' && C <= 'f') return C-'a'+10U;
+  if (C >= 'A' && C <= 'F') return C-'A'+10U;
+  return -1U;
+}
+
 /// utohex_buffer - Emit the specified number into the buffer specified by
 /// BufferEnd, returning a pointer to the start of the string.  This can be used
 /// like this: (note that the buffer must be large enough to handle any number):
@@ -129,6 +140,25 @@ static inline unsigned HashString(StringRef Str, unsigned Result = 0) {
   return Result;
 }
 
+/// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th).
+static inline StringRef getOrdinalSuffix(unsigned Val) {
+  // It is critically important that we do this perfectly for
+  // user-written sequences with over 100 elements.
+  switch (Val % 100) {
+  case 11:
+  case 12:
+  case 13:
+    return "th";
+  default:
+    switch (Val % 10) {
+      case 1: return "st";
+      case 2: return "nd";
+      case 3: return "rd";
+      default: return "th";
+    }
+  }
+}
+
 } // End llvm namespace
 
 #endif