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//===- llvm/ADT/StringExtras.h - Useful string functions --------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

///

/// \file

/// This file contains some functions that are useful when dealing with strings.

///

//===----------------------------------------------------------------------===//

#ifndef LLVM_ADT_STRINGEXTRAS_H

#define LLVM_ADT_STRINGEXTRAS_H

#include "llvm/ADT/APSInt.h"

#include "llvm/ADT/ArrayRef.h"

#include "llvm/ADT/SmallString.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/ADT/Twine.h"

#include <cassert>

#include <cstddef>

#include <cstdint>

#include <cstdlib>

#include <cstring>

#include <iterator>

#include <string>

#include <utility>

namespace llvm {

class raw_ostream;

/// hexdigit - Return the hexadecimal character for the

/// given number \p X (which should be less than 16).

inline char hexdigit(unsigned X, bool LowerCase = false) {

  assert(X < 16);

  static const char LUT[] = "0123456789ABCDEF";

  const uint8_t Offset = LowerCase ? 32 : 0;

  return LUT[X] | Offset;

}

/// Given an array of c-style strings terminated by a null pointer, construct

/// a vector of StringRefs representing the same strings without the terminating

/// null string.

inline std::vector<StringRef> toStringRefArray(const char *const *Strings) {

  std::vector<StringRef> Result;

  while (*Strings)

    Result.push_back(*Strings++);

  return Result;

}

/// Construct a string ref from a boolean.

inline StringRef toStringRef(bool B) { return StringRef(B ? "true" : "false"); }

/// Construct a string ref from an array ref of unsigned chars.

inline StringRef toStringRef(ArrayRef<uint8_t> Input) {

  return StringRef(reinterpret_cast<const char *>(Input.begin()), Input.size());

}

/// Construct a string ref from an array ref of unsigned chars.

inline ArrayRef<uint8_t> arrayRefFromStringRef(StringRef Input) {

  return {Input.bytes_begin(), Input.bytes_end()};

}

/// 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.

inline unsigned hexDigitValue(char C) {

  /* clang-format off */

  static const int16_t LUT[256] = {

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

     0,  1,  2,  3,  4,  5,  6,  7,  8,  9, -1, -1, -1, -1, -1, -1,  // '0'..'9'

    -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 'A'..'F'

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 'a'..'f'

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,

  };

  /* clang-format on */

  return LUT[static_cast<unsigned char>(C)];

}

/// Checks if character \p C is one of the 10 decimal digits.

inline bool isDigit(char C) { return C >= '0' && C <= '9'; }

/// Checks if character \p C is a hexadecimal numeric character.

inline bool isHexDigit(char C) { return hexDigitValue(C) != ~0U; }

/// Checks if character \p C is a valid letter as classified by "C" locale.

inline bool isAlpha(char C) {

  return ('a' <= C && C <= 'z') || ('A' <= C && C <= 'Z');

}

/// Checks whether character \p C is either a decimal digit or an uppercase or

/// lowercase letter as classified by "C" locale.

inline bool isAlnum(char C) { return isAlpha(C) || isDigit(C); }

/// Checks whether character \p C is valid ASCII (high bit is zero).

inline bool isASCII(char C) { return static_cast<unsigned char>(C) <= 127; }

/// Checks whether all characters in S are ASCII.

inline bool isASCII(llvm::StringRef S) {

  for (char C : S)

    if (LLVM_UNLIKELY(!isASCII(C)))

      return false;

  return true;

}

/// Checks whether character \p C is printable.

///

/// Locale-independent version of the C standard library isprint whose results

/// may differ on different platforms.

inline bool isPrint(char C) {

  unsigned char UC = static_cast<unsigned char>(C);

  return (0x20 <= UC) && (UC <= 0x7E);

}

/// Checks whether character \p C is whitespace in the "C" locale.

///

/// Locale-independent version of the C standard library isspace.

inline bool isSpace(char C) {

  return C == ' ' || C == '\f' || C == '\n' || C == '\r' || C == '\t' ||

         C == '\v';

}

/// Returns the corresponding lowercase character if \p x is uppercase.

inline char toLower(char x) {

  if (x >= 'A' && x <= 'Z')

    return x - 'A' + 'a';

  return x;

}

/// Returns the corresponding uppercase character if \p x is lowercase.

inline char toUpper(char x) {

  if (x >= 'a' && x <= 'z')

    return x - 'a' + 'A';

  return x;

}

inline std::string utohexstr(uint64_t X, bool LowerCase = false,

                             unsigned Width = 0) {

  char Buffer[17];

  char *BufPtr = std::end(Buffer);

  if (X == 0) *--BufPtr = '0';

  for (unsigned i = 0; Width ? (i < Width) : X; ++i) {

    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.

inline void toHex(ArrayRef<uint8_t> Input, bool LowerCase,

                  SmallVectorImpl<char> &Output) {

  const size_t Length = Input.size();

  Output.resize_for_overwrite(Length * 2);

  for (size_t i = 0; i < Length; i++) {

    const uint8_t c = Input[i];

    Output[i * 2    ] = hexdigit(c >> 4, LowerCase);

    Output[i * 2 + 1] = hexdigit(c & 15, LowerCase);

  }

}

inline std::string toHex(ArrayRef<uint8_t> Input, bool LowerCase = false) {

  SmallString<16> Output;

  toHex(Input, LowerCase, Output);

  return std::string(Output);

}

inline std::string toHex(StringRef Input, bool LowerCase = false) {

  return toHex(arrayRefFromStringRef(Input), LowerCase);

}

/// Store the binary representation of the two provided values, \p MSB and

/// \p LSB, that make up the nibbles of a hexadecimal digit. If \p MSB or \p LSB

/// do not correspond to proper nibbles of a hexadecimal digit, this method

/// returns false. Otherwise, returns true.

inline bool tryGetHexFromNibbles(char MSB, char LSB, uint8_t &Hex) {

  unsigned U1 = hexDigitValue(MSB);

  unsigned U2 = hexDigitValue(LSB);

  if (U1 == ~0U || U2 == ~0U)

    return false;

  Hex = static_cast<uint8_t>((U1 << 4) | U2);

  return true;

}

/// Return the binary representation of the two provided values, \p MSB and

/// \p LSB, that make up the nibbles of a hexadecimal digit.

inline uint8_t hexFromNibbles(char MSB, char LSB) {

  uint8_t Hex = 0;

  bool GotHex = tryGetHexFromNibbles(MSB, LSB, Hex);

  (void)GotHex;

  assert(GotHex && "MSB and/or LSB do not correspond to hex digits");

  return Hex;

}

/// Convert hexadecimal string \p Input to its binary representation and store

/// the result in \p Output. Returns true if the binary representation could be

/// converted from the hexadecimal string. Returns false if \p Input contains

/// non-hexadecimal digits. The output string is half the size of \p Input.

inline bool tryGetFromHex(StringRef Input, std::string &Output) {

  if (Input.empty())

    return true;

  // If the input string is not properly aligned on 2 nibbles we pad out the

  // front with a 0 prefix; e.g. `ABC` -> `0ABC`.

  Output.resize((Input.size() + 1) / 2);

  char *OutputPtr = const_cast<char *>(Output.data());

  if (Input.size() % 2 == 1) {

    uint8_t Hex = 0;

    if (!tryGetHexFromNibbles('0', Input.front(), Hex))

      return false;

    *OutputPtr++ = Hex;

    Input = Input.drop_front();

  }

  // Convert the nibble pairs (e.g. `9C`) into bytes (0x9C).

  // With the padding above we know the input is aligned and the output expects

  // exactly half as many bytes as nibbles in the input.

  size_t InputSize = Input.size();

  assert(InputSize % 2 == 0);

  const char *InputPtr = Input.data();

  for (size_t OutputIndex = 0; OutputIndex < InputSize / 2; ++OutputIndex) {

    uint8_t Hex = 0;

    if (!tryGetHexFromNibbles(InputPtr[OutputIndex * 2 + 0], // MSB

                              InputPtr[OutputIndex * 2 + 1], // LSB

                              Hex))

      return false;

    OutputPtr[OutputIndex] = Hex;

  }

  return true;

}

/// Convert hexadecimal string \p Input to its binary representation.

/// The return string is half the size of \p Input.

inline std::string fromHex(StringRef Input) {

  std::string Hex;

  bool GotHex = tryGetFromHex(Input, Hex);

  (void)GotHex;

  assert(GotHex && "Input contains non hex digits");

  return Hex;

}

/// Convert the string \p S to an integer of the specified type using

/// the radix \p Base.  If \p Base is 0, auto-detects the radix.

/// Returns true if the number was successfully converted, false otherwise.

template <typename N> bool to_integer(StringRef S, N &Num, unsigned Base = 0) {

  return !S.getAsInteger(Base, Num);

}

namespace detail {

template <typename N>

inline bool to_float(const Twine &T, N &Num, N (*StrTo)(const char *, char **)) {

  SmallString<32> Storage;

  StringRef S = T.toNullTerminatedStringRef(Storage);

  char *End;

  N Temp = StrTo(S.data(), &End);

  if (*End != '\0')

    return false;

  Num = Temp;

  return true;

}

}

inline bool to_float(const Twine &T, float &Num) {

  return detail::to_float(T, Num, strtof);

}

inline bool to_float(const Twine &T, double &Num) {

  return detail::to_float(T, Num, strtod);

}

inline bool to_float(const Twine &T, long double &Num) {

  return detail::to_float(T, Num, strtold);

}

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));

}

inline std::string itostr(int64_t X) {

  if (X < 0)

    return utostr(static_cast<uint64_t>(1) + ~static_cast<uint64_t>(X), true);

  else

    return utostr(static_cast<uint64_t>(X));

}

inline std::string toString(const APInt &I, unsigned Radix, bool Signed,

                            bool formatAsCLiteral = false) {

  SmallString<40> S;

  I.toString(S, Radix, Signed, formatAsCLiteral);

  return std::string(S.str());

}

inline std::string toString(const APSInt &I, unsigned Radix) {

  return toString(I, Radix, I.isSigned());

}

/// 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");

/// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th).

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";

    }

  }

}

/// Print each character of the specified string, escaping it if it is not

/// printable or if it is an escape char.

void printEscapedString(StringRef Name, raw_ostream &Out);

/// Print each character of the specified string, escaping HTML special

/// characters.

void printHTMLEscaped(StringRef String, raw_ostream &Out);

/// printLowerCase - Print each character as lowercase if it is uppercase.

void printLowerCase(StringRef String, raw_ostream &Out);

/// Converts a string from camel-case to snake-case by replacing all uppercase

/// letters with '_' followed by the letter in lowercase, except if the

/// uppercase letter is the first character of the string.

std::string convertToSnakeFromCamelCase(StringRef input);

/// Converts a string from snake-case to camel-case by replacing all occurrences

/// of '_' followed by a lowercase letter with the letter in uppercase.

/// Optionally allow capitalization of the first letter (if it is a lowercase

/// letter)

std::string convertToCamelFromSnakeCase(StringRef input,

                                        bool capitalizeFirst = false);

namespace detail {

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 += (*I).size();

  S.reserve(Len);

  size_t PrevCapacity = S.capacity();

  (void)PrevCapacity;

  S += (*Begin);

  while (++Begin != End) {

    S += Separator;

    S += (*Begin);

  }

  assert(PrevCapacity == S.capacity() && "String grew during building");

  return S;

}

template <typename Sep>

inline void join_items_impl(std::string &Result, Sep Separator) {}

template <typename Sep, typename Arg>

inline void join_items_impl(std::string &Result, Sep Separator,

                            const Arg &Item) {

  Result += Item;

}

template <typename Sep, typename Arg1, typename... Args>

inline void join_items_impl(std::string &Result, Sep Separator, const Arg1 &A1,

                            Args &&... Items) {

  Result += A1;

  Result += Separator;

  join_items_impl(Result, Separator, std::forward<Args>(Items)...);

}

inline size_t join_one_item_size(char) { return 1; }

inline size_t join_one_item_size(const char *S) { return S ? ::strlen(S) : 0; }

template <typename T> inline size_t join_one_item_size(const T &Str) {

  return Str.size();

}

template <typename... Args> inline size_t join_items_size(Args &&...Items) {

  return (0 + ... + join_one_item_size(std::forward<Args>(Items)));

}

} // end namespace detail

/// 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) {

  using tag = typename std::iterator_traits<IteratorT>::iterator_category;

  return detail::join_impl(Begin, End, Separator, tag());

}

/// Joins the strings in the range [R.begin(), R.end()), adding Separator

/// between the elements.

template <typename Range>

inline std::string join(Range &&R, StringRef Separator) {

  return join(R.begin(), R.end(), Separator);

}

/// Joins the strings in the parameter pack \p Items, adding \p Separator

/// between the elements.  All arguments must be implicitly convertible to

/// std::string, or there should be an overload of std::string::operator+=()

/// that accepts the argument explicitly.

template <typename Sep, typename... Args>

inline std::string join_items(Sep Separator, Args &&... Items) {

  std::string Result;

  if (sizeof...(Items) == 0)

    return Result;

  size_t NS = detail::join_one_item_size(Separator);

  size_t NI = detail::join_items_size(std::forward<Args>(Items)...);

  Result.reserve(NI + (sizeof...(Items) - 1) * NS + 1);

  detail::join_items_impl(Result, Separator, std::forward<Args>(Items)...);

  return Result;

}

/// A helper class to return the specified delimiter string after the first

/// invocation of operator StringRef().  Used to generate a comma-separated

/// list from a loop like so:

///

/// \code

///   ListSeparator LS;

///   for (auto &I : C)

///     OS << LS << I.getName();

/// \end

class ListSeparator {

  bool First = true;

  StringRef Separator;

public:

  ListSeparator(StringRef Separator = ", ") : Separator(Separator) {}

  operator StringRef() {

    if (First) {

      First = false;

      return {};

    }

    return Separator;

  }

};

/// A forward iterator over partitions of string over a separator.

class SplittingIterator

    : public iterator_facade_base<SplittingIterator, std::forward_iterator_tag,

                                  StringRef> {

  char SeparatorStorage;

  StringRef Current;

  StringRef Next;

  StringRef Separator;

public:

  SplittingIterator(StringRef Str, StringRef Separator)

      : Next(Str), Separator(Separator) {

    ++*this;

  }

  SplittingIterator(StringRef Str, char Separator)

      : SeparatorStorage(Separator), Next(Str),

        Separator(&SeparatorStorage, 1) {

    ++*this;

  }

  SplittingIterator(const SplittingIterator &R)

      : SeparatorStorage(R.SeparatorStorage), Current(R.Current), Next(R.Next),

        Separator(R.Separator) {

    if (R.Separator.data() == &R.SeparatorStorage)

      Separator = StringRef(&SeparatorStorage, 1);

  }

  SplittingIterator &operator=(const SplittingIterator &R) {

    if (this == &R)

      return *this;

    SeparatorStorage = R.SeparatorStorage;

    Current = R.Current;

    Next = R.Next;

    Separator = R.Separator;

    if (R.Separator.data() == &R.SeparatorStorage)

      Separator = StringRef(&SeparatorStorage, 1);

    return *this;

  }

  bool operator==(const SplittingIterator &R) const {

    assert(Separator == R.Separator);

    return Current.data() == R.Current.data();

  }

  const StringRef &operator*() const { return Current; }

  StringRef &operator*() { return Current; }

  SplittingIterator &operator++() {

    std::tie(Current, Next) = Next.split(Separator);

    return *this;

  }

};

/// Split the specified string over a separator and return a range-compatible

/// iterable over its partitions.  Used to permit conveniently iterating

/// over separated strings like so:

///

/// \code

///   for (StringRef x : llvm::split("foo,bar,baz", ","))

///     ...;

/// \end

///

/// Note that the passed string must remain valid throuhgout lifetime

/// of the iterators.

inline iterator_range<SplittingIterator> split(StringRef Str, StringRef Separator) {

  return {SplittingIterator(Str, Separator),

          SplittingIterator(StringRef(), Separator)};

}

inline iterator_range<SplittingIterator> split(StringRef Str, char Separator) {

  return {SplittingIterator(Str, Separator),

          SplittingIterator(StringRef(), Separator)};

}

} // end namespace llvm

#endif // LLVM_ADT_STRINGEXTRAS_H