Prepare wpiutil for merge into allwpilib.

wpiutil/src/main/native/include/llvm/StringExtras.h

@@ -0,0 +1,197 @@
+//===-- llvm/ADT/StringExtras.h - Useful string functions -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains some functions that are useful when dealing with strings.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_STRINGEXTRAS_H
+#define LLVM_ADT_STRINGEXTRAS_H
+
+#include "llvm/StringRef.h"
+#include <cstdint>
+#include <iterator>
+
+namespace llvm {
+template<typename T> class SmallVectorImpl;
+
+/// hexdigit - Return the hexadecimal character for the
+/// 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;
+}
+
+/// Construct a string ref from a boolean.
+static inline StringRef toStringRef(bool B) {
+  return StringRef(B ? "true" : "false");
+}
+
+/// 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;
+}
+
+static inline std::string utohexstr(uint64_t X, bool LowerCase = false) {
+  char Buffer[17];
+  char *BufPtr = std::end(Buffer);
+
+  if (X == 0) *--BufPtr = '0';
+
+  while (X) {
+    unsigned char Mod = static_cast<unsigned char>(X) & 15;
+    *--BufPtr = hexdigit(Mod, LowerCase);
+    X >>= 4;
+  }
+
+  return std::string(BufPtr, std::end(Buffer));
+}
+
+/// Convert buffer \p Input to its hexadecimal representation.
+/// The returned string is double the size of \p Input.
+static inline std::string toHex(StringRef Input) {
+  static const char *const LUT = "0123456789ABCDEF";
+  size_t Length = Input.size();
+
+  std::string Output;
+  Output.reserve(2 * Length);
+  for (size_t i = 0; i < Length; ++i) {
+    const unsigned char c = Input[i];
+    Output.push_back(LUT[c >> 4]);
+    Output.push_back(LUT[c & 15]);
+  }
+  return Output;
+}
+
+static inline std::string utostr(uint64_t X, bool isNeg = false) {
+  char Buffer[21];
+  char *BufPtr = std::end(Buffer);
+
+  if (X == 0) *--BufPtr = '0';  // Handle special case...
+
+  while (X) {
+    *--BufPtr = '0' + char(X % 10);
+    X /= 10;
+  }
+
+  if (isNeg) *--BufPtr = '-';   // Add negative sign...
+  return std::string(BufPtr, std::end(Buffer));
+}
+
+
+static inline std::string itostr(int64_t X) {
+  if (X < 0)
+    return utostr(static_cast<uint64_t>(-X), true);
+  else
+    return utostr(static_cast<uint64_t>(X));
+}
+
+/// StrInStrNoCase - Portable version of strcasestr.  Locates the first
+/// occurrence of string 's1' in string 's2', ignoring case.  Returns
+/// the offset of s2 in s1 or npos if s2 cannot be found.
+StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2);
+
+/// getToken - This function extracts one token from source, ignoring any
+/// leading characters that appear in the Delimiters string, and ending the
+/// token at any of the characters that appear in the Delimiters string.  If
+/// there are no tokens in the source string, an empty string is returned.
+/// The function returns a pair containing the extracted token and the
+/// remaining tail string.
+std::pair<StringRef, StringRef> getToken(StringRef Source,
+                                         StringRef Delimiters = " \t\n\v\f\r");
+
+/// SplitString - Split up the specified string according to the specified
+/// delimiters, appending the result fragments to the output list.
+void SplitString(StringRef Source,
+                 SmallVectorImpl<StringRef> &OutFragments,
+                 StringRef Delimiters = " \t\n\v\f\r");
+
+/// HashString - Hash function for strings.
+///
+/// This is the Bernstein hash function.
+//
+// FIXME: Investigate whether a modified bernstein hash function performs
+// better: http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
+//   X*33+c -> X*33^c
+static inline unsigned HashString(StringRef Str, unsigned Result = 0) {
+  for (StringRef::size_type i = 0, e = Str.size(); i != e; ++i)
+    Result = Result * 33 + (unsigned char)Str[i];
+  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";
+    }
+  }
+}
+
+template <typename IteratorT>
+inline std::string join_impl(IteratorT Begin, IteratorT End,
+                             StringRef Separator, std::input_iterator_tag) {
+  std::string S;
+  if (Begin == End)
+    return S;
+
+  S += (*Begin);
+  while (++Begin != End) {
+    S += Separator;
+    S += (*Begin);
+  }
+  return S;
+}
+
+template <typename IteratorT>
+inline std::string join_impl(IteratorT Begin, IteratorT End,
+                             StringRef Separator, std::forward_iterator_tag) {
+  std::string S;
+  if (Begin == End)
+    return S;
+
+  size_t Len = (std::distance(Begin, End) - 1) * Separator.size();
+  for (IteratorT I = Begin; I != End; ++I)
+    Len += (*Begin).size();
+  S.reserve(Len);
+  S += (*Begin);
+  while (++Begin != End) {
+    S += Separator;
+    S += (*Begin);
+  }
+  return S;
+}
+
+/// Joins the strings in the range [Begin, End), adding Separator between
+/// the elements.
+template <typename IteratorT>
+inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) {
+  typedef typename std::iterator_traits<IteratorT>::iterator_category tag;
+  return join_impl(Begin, End, Separator, tag());
+}
+
+} // End llvm namespace
+
+#endif