Import LLVM StringMap et al.

Change-Id: Ic48c722c2856c7aa36001935adbcf31b986ac1f3

src/llvm/StringRef.cpp

@@ -0,0 +1,371 @@
+//===-- StringRef.cpp - Lightweight String References ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/StringRef.h"
+#include <bitset>
+#include <climits>
+
+using namespace llvm;
+
+// MSVC emits references to this into the translation units which reference it.
+#ifndef _MSC_VER
+const size_t StringRef::npos;
+#endif
+
+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;
+}
+
+//===----------------------------------------------------------------------===//
+// 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;
+}
+
+//===----------------------------------------------------------------------===//
+// String Searching
+//===----------------------------------------------------------------------===//
+
+
+/// find - Search for the first string \arg Str in the string.
+///
+/// \return - The index of the first occurrence of \arg Str, or npos if not
+/// found.
+size_t StringRef::find(StringRef Str, size_t From) const {
+  size_t N = Str.size();
+  if (N > Length)
+    return npos;
+
+  // For short haystacks or unsupported needles fall back to the naive algorithm
+  if (Length < 16 || N > 255 || N == 0) {
+    for (size_t e = Length - N + 1, i = std::min(From, e); i != e; ++i)
+      if (substr(i, N).equals(Str))
+        return i;
+    return npos;
+  }
+
+  if (From >= Length)
+    return npos;
+
+  // Build the bad char heuristic table, with uint8_t to reduce cache thrashing.
+  uint8_t BadCharSkip[256];
+  std::memset(BadCharSkip, N, 256);
+  for (unsigned i = 0; i != N-1; ++i)
+    BadCharSkip[(uint8_t)Str[i]] = N-1-i;
+
+  unsigned Len = Length-From, Pos = From;
+  while (Len >= N) {
+    if (substr(Pos, N).equals(Str)) // See if this is the correct substring.
+      return Pos;
+
+    // Otherwise skip the appropriate number of bytes.
+    uint8_t Skip = BadCharSkip[(uint8_t)(*this)[Pos+N-1]];
+    Len -= Skip;
+    Pos += Skip;
+  }
+
+  return npos;
+}
+
+/// rfind - Search for the last string \arg Str in the string.
+///
+/// \return - The index of the last occurrence of \arg Str, or npos if not
+/// found.
+size_t StringRef::rfind(StringRef Str) const {
+  size_t N = Str.size();
+  if (N > Length)
+    return npos;
+  for (size_t i = Length - N + 1, e = 0; i != e;) {
+    --i;
+    if (substr(i, N).equals(Str))
+      return i;
+  }
+  return npos;
+}
+
+/// find_first_of - Find the first character in the string that is in \arg
+/// Chars, or npos if not found.
+///
+/// Note: O(size() + Chars.size())
+StringRef::size_type StringRef::find_first_of(StringRef Chars,
+                                              size_t From) const {
+  std::bitset<1 << CHAR_BIT> CharBits;
+  for (size_type i = 0; i != Chars.size(); ++i)
+    CharBits.set((unsigned char)Chars[i]);
+
+  for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
+    if (CharBits.test((unsigned char)Data[i]))
+      return i;
+  return npos;
+}
+
+/// find_first_not_of - Find the first character in the string that is not
+/// \arg C or npos if not found.
+StringRef::size_type StringRef::find_first_not_of(char C, size_t From) const {
+  for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
+    if (Data[i] != C)
+      return i;
+  return npos;
+}
+
+/// find_first_not_of - Find the first character in the string that is not
+/// in the string \arg Chars, or npos if not found.
+///
+/// Note: O(size() + Chars.size())
+StringRef::size_type StringRef::find_first_not_of(StringRef Chars,
+                                                  size_t From) const {
+  std::bitset<1 << CHAR_BIT> CharBits;
+  for (size_type i = 0; i != Chars.size(); ++i)
+    CharBits.set((unsigned char)Chars[i]);
+
+  for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
+    if (!CharBits.test((unsigned char)Data[i]))
+      return i;
+  return npos;
+}
+
+/// find_last_of - Find the last character in the string that is in \arg C,
+/// or npos if not found.
+///
+/// Note: O(size() + Chars.size())
+StringRef::size_type StringRef::find_last_of(StringRef Chars,
+                                             size_t From) const {
+  std::bitset<1 << CHAR_BIT> CharBits;
+  for (size_type i = 0; i != Chars.size(); ++i)
+    CharBits.set((unsigned char)Chars[i]);
+
+  for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
+    if (CharBits.test((unsigned char)Data[i]))
+      return i;
+  return npos;
+}
+
+/// find_last_not_of - Find the last character in the string that is not
+/// \arg C, or npos if not found.
+StringRef::size_type StringRef::find_last_not_of(char C, size_t From) const {
+  for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
+    if (Data[i] != C)
+      return i;
+  return npos;
+}
+
+/// find_last_not_of - Find the last character in the string that is not in
+/// \arg Chars, or npos if not found.
+///
+/// Note: O(size() + Chars.size())
+StringRef::size_type StringRef::find_last_not_of(StringRef Chars,
+                                                 size_t From) const {
+  std::bitset<1 << CHAR_BIT> CharBits;
+  for (size_type i = 0, e = Chars.size(); i != e; ++i)
+    CharBits.set((unsigned char)Chars[i]);
+
+  for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
+    if (!CharBits.test((unsigned char)Data[i]))
+      return i;
+  return npos;
+}
+
+//===----------------------------------------------------------------------===//
+// Helpful Algorithms
+//===----------------------------------------------------------------------===//
+
+/// count - Return the number of non-overlapped occurrences of \arg Str in
+/// the string.
+size_t StringRef::count(StringRef Str) const {
+  size_t Count = 0;
+  size_t N = Str.size();
+  if (N > Length)
+    return 0;
+  for (size_t i = 0, e = Length - N + 1; i != e; ++i)
+    if (substr(i, N).equals(Str))
+      ++Count;
+  return Count;
+}
+
+static unsigned GetAutoSenseRadix(StringRef &Str) {
+  if (Str.startswith("0x")) {
+    Str = Str.substr(2);
+    return 16;
+  }
+  
+  if (Str.startswith("0b")) {
+    Str = Str.substr(2);
+    return 2;
+  }
+
+  if (Str.startswith("0o")) {
+    Str = Str.substr(2);
+    return 8;
+  }
+
+  if (Str.startswith("0"))
+    return 8;
+  
+  return 10;
+}
+
+
+/// GetAsUnsignedInteger - Workhorse method that converts a integer character
+/// sequence of radix up to 36 to an unsigned long long value.
+bool llvm::getAsUnsignedInteger(StringRef Str, unsigned Radix,
+                                unsigned long long &Result) {
+  // Autosense radix if not specified.
+  if (Radix == 0)
+    Radix = GetAutoSenseRadix(Str);
+
+  // Empty strings (after the radix autosense) are invalid.
+  if (Str.empty()) return true;
+
+  // Parse all the bytes of the string given this radix.  Watch for overflow.
+  Result = 0;
+  while (!Str.empty()) {
+    unsigned CharVal;
+    if (Str[0] >= '0' && Str[0] <= '9')
+      CharVal = Str[0]-'0';
+    else if (Str[0] >= 'a' && Str[0] <= 'z')
+      CharVal = Str[0]-'a'+10;
+    else if (Str[0] >= 'A' && Str[0] <= 'Z')
+      CharVal = Str[0]-'A'+10;
+    else
+      return true;
+
+    // If the parsed value is larger than the integer radix, the string is
+    // invalid.
+    if (CharVal >= Radix)
+      return true;
+
+    // Add in this character.
+    unsigned long long PrevResult = Result;
+    Result = Result*Radix+CharVal;
+
+    // Check for overflow by shifting back and seeing if bits were lost.
+    if (Result/Radix < PrevResult)
+      return true;
+
+    Str = Str.substr(1);
+  }
+
+  return false;
+}
+
+bool llvm::getAsSignedInteger(StringRef Str, unsigned Radix,
+                              long long &Result) {
+  unsigned long long ULLVal;
+
+  // Handle positive strings first.
+  if (Str.empty() || Str.front() != '-') {
+    if (getAsUnsignedInteger(Str, Radix, ULLVal) ||
+        // Check for value so large it overflows a signed value.
+        (long long)ULLVal < 0)
+      return true;
+    Result = ULLVal;
+    return false;
+  }
+
+  // Get the positive part of the value.
+  if (getAsUnsignedInteger(Str.substr(1), Radix, ULLVal) ||
+      // Reject values so large they'd overflow as negative signed, but allow
+      // "-0".  This negates the unsigned so that the negative isn't undefined
+      // on signed overflow.
+      (long long)-ULLVal > 0)
+    return true;
+
+  Result = -ULLVal;
+  return false;
+}