text: //===--- LiteralSupport.h ---------------------------------------*- C++ -*-===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file defines the NumericLiteralParser, CharLiteralParser, and
  // StringLiteralParser interfaces.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef CLANG_LITERALSUPPORT_H
  #define CLANG_LITERALSUPPORT_H
  
  #include "clang/Basic/CharInfo.h"
  #include "clang/Basic/LLVM.h"
  #include "clang/Basic/TokenKinds.h"
  #include "llvm/ADT/APFloat.h"
  #include "llvm/ADT/SmallString.h"
  #include "llvm/ADT/StringRef.h"
  #include "llvm/Support/DataTypes.h"
  
  namespace clang {
  
  class DiagnosticsEngine;
  class Preprocessor;
  class Token;
  class SourceLocation;
  class TargetInfo;
  class SourceManager;
  class LangOptions;
  
  /// Copy characters from Input to Buf, expanding any UCNs.
  void expandUCNs(SmallVectorImpl<char> &Buf, StringRef Input);
  
  /// NumericLiteralParser - This performs strict semantic analysis of the content
  /// of a ppnumber, classifying it as either integer, floating, or erroneous,
  /// determines the radix of the value and can convert it to a useful value.
  class NumericLiteralParser {
    Preprocessor &PP; // needed for diagnostics
  
    const char *const ThisTokBegin;
    const char *const ThisTokEnd;
    const char *DigitsBegin, *SuffixBegin; // markers
    const char *s; // cursor
  
    unsigned radix;
  
    bool saw_exponent, saw_period, saw_ud_suffix;
  
    SmallString<32> UDSuffixBuf;
  
  public:
    NumericLiteralParser(StringRef TokSpelling,
                         SourceLocation TokLoc,
                         Preprocessor &PP);
    bool hadError;
    bool isUnsigned;
    bool isLong;        // This is *not* set for long long.
    bool isLongLong;
    bool isFloat;       // 1.0f
    bool isImaginary;   // 1.0i
    uint8_t MicrosoftInteger;  // Microsoft suffix extension i8, i16, i32, or i64.
  
    bool isIntegerLiteral() const {
      return !saw_period && !saw_exponent;
    }
    bool isFloatingLiteral() const {
      return saw_period || saw_exponent;
    }
  
    bool hasUDSuffix() const {
      return saw_ud_suffix;
    }
    StringRef getUDSuffix() const {
      assert(saw_ud_suffix);
      return UDSuffixBuf;
    }
    unsigned getUDSuffixOffset() const {
      assert(saw_ud_suffix);
      return SuffixBegin - ThisTokBegin;
    }
  
    static bool isValidUDSuffix(const LangOptions &LangOpts, StringRef Suffix);
  
    unsigned getRadix() const { return radix; }
  
    /// GetIntegerValue - Convert this numeric literal value to an APInt that
    /// matches Val's input width.  If there is an overflow (i.e., if the unsigned
    /// value read is larger than the APInt's bits will hold), set Val to the low
    /// bits of the result and return true.  Otherwise, return false.
    bool GetIntegerValue(llvm::APInt &Val);
  
    /// GetFloatValue - Convert this numeric literal to a floating value, using
    /// the specified APFloat fltSemantics (specifying float, double, etc).
    /// The optional bool isExact (passed-by-reference) has its value
    /// set to true if the returned APFloat can represent the number in the
    /// literal exactly, and false otherwise.
    llvm::APFloat::opStatus GetFloatValue(llvm::APFloat &Result);
  
  private:
  
    void ParseNumberStartingWithZero(SourceLocation TokLoc);
  
    static bool isDigitSeparator(char C) { return C == '\''; }
  
    enum CheckSeparatorKind { CSK_BeforeDigits, CSK_AfterDigits };
  
    /// \brief Ensure that we don't have a digit separator here.
    void checkSeparator(SourceLocation TokLoc, const char *Pos,
                        CheckSeparatorKind IsAfterDigits);
  
    /// SkipHexDigits - Read and skip over any hex digits, up to End.
    /// Return a pointer to the first non-hex digit or End.
    const char *SkipHexDigits(const char *ptr) {
      while (ptr != ThisTokEnd && (isHexDigit(*ptr) || isDigitSeparator(*ptr)))
        ptr++;
      return ptr;
    }
  
    /// SkipOctalDigits - Read and skip over any octal digits, up to End.
    /// Return a pointer to the first non-hex digit or End.
    const char *SkipOctalDigits(const char *ptr) {
      while (ptr != ThisTokEnd &&
             ((*ptr >= '0' && *ptr <= '7') || isDigitSeparator(*ptr)))
        ptr++;
      return ptr;
    }
  
    /// SkipDigits - Read and skip over any digits, up to End.
    /// Return a pointer to the first non-hex digit or End.
    const char *SkipDigits(const char *ptr) {
      while (ptr != ThisTokEnd && (isDigit(*ptr) || isDigitSeparator(*ptr)))
        ptr++;
      return ptr;
    }
  
    /// SkipBinaryDigits - Read and skip over any binary digits, up to End.
    /// Return a pointer to the first non-binary digit or End.
    const char *SkipBinaryDigits(const char *ptr) {
      while (ptr != ThisTokEnd &&
             (*ptr == '0' || *ptr == '1' || isDigitSeparator(*ptr)))
        ptr++;
      return ptr;
    }
  
  };
  
  /// CharLiteralParser - Perform interpretation and semantic analysis of a
  /// character literal.
  class CharLiteralParser {
    uint64_t Value;
    tok::TokenKind Kind;
    bool IsMultiChar;
    bool HadError;
    SmallString<32> UDSuffixBuf;
    unsigned UDSuffixOffset;
  public:
    CharLiteralParser(const char *begin, const char *end,
                      SourceLocation Loc, Preprocessor &PP,
                      tok::TokenKind kind);
  
    bool hadError() const { return HadError; }
    bool isAscii() const { return Kind == tok::char_constant; }
    bool isWide() const { return Kind == tok::wide_char_constant; }
    bool isUTF16() const { return Kind == tok::utf16_char_constant; }
    bool isUTF32() const { return Kind == tok::utf32_char_constant; }
    bool isMultiChar() const { return IsMultiChar; }
    uint64_t getValue() const { return Value; }
    StringRef getUDSuffix() const { return UDSuffixBuf; }
    unsigned getUDSuffixOffset() const {
      assert(!UDSuffixBuf.empty() && "no ud-suffix");
      return UDSuffixOffset;
    }
  };
  
  /// StringLiteralParser - This decodes string escape characters and performs
  /// wide string analysis and Translation Phase #6 (concatenation of string
  /// literals) (C99 5.1.1.2p1).
  class StringLiteralParser {
    const SourceManager &SM;
    const LangOptions &Features;
    const TargetInfo &Target;
    DiagnosticsEngine *Diags;
    
    unsigned MaxTokenLength;
    unsigned SizeBound;
    unsigned CharByteWidth;
    tok::TokenKind Kind;
    SmallString<512> ResultBuf;
    char *ResultPtr; // cursor
    SmallString<32> UDSuffixBuf;
    unsigned UDSuffixToken;
    unsigned UDSuffixOffset;
  public:
    StringLiteralParser(ArrayRef<Token> StringToks,
                        Preprocessor &PP, bool Complain = true);
    StringLiteralParser(ArrayRef<Token> StringToks,
                        const SourceManager &sm, const LangOptions &features,
                        const TargetInfo &target,
                        DiagnosticsEngine *diags = nullptr)
      : SM(sm), Features(features), Target(target), Diags(diags),
        MaxTokenLength(0), SizeBound(0), CharByteWidth(0), Kind(tok::unknown),
        ResultPtr(ResultBuf.data()), hadError(false), Pascal(false) {
      init(StringToks);
    }
      
  
    bool hadError;
    bool Pascal;
  
    StringRef GetString() const {
      return StringRef(ResultBuf.data(), GetStringLength());
    }
    unsigned GetStringLength() const { return ResultPtr-ResultBuf.data(); }
  
    unsigned GetNumStringChars() const {
      return GetStringLength() / CharByteWidth;
    }
    /// getOffsetOfStringByte - This function returns the offset of the
    /// specified byte of the string data represented by Token.  This handles
    /// advancing over escape sequences in the string.
    ///
    /// If the Diagnostics pointer is non-null, then this will do semantic
    /// checking of the string literal and emit errors and warnings.
    unsigned getOffsetOfStringByte(const Token &TheTok, unsigned ByteNo) const;
  
    bool isAscii() const { return Kind == tok::string_literal; }
    bool isWide() const { return Kind == tok::wide_string_literal; }
    bool isUTF8() const { return Kind == tok::utf8_string_literal; }
    bool isUTF16() const { return Kind == tok::utf16_string_literal; }
    bool isUTF32() const { return Kind == tok::utf32_string_literal; }
    bool isPascal() const { return Pascal; }
  
    StringRef getUDSuffix() const { return UDSuffixBuf; }
  
    /// Get the index of a token containing a ud-suffix.
    unsigned getUDSuffixToken() const {
      assert(!UDSuffixBuf.empty() && "no ud-suffix");
      return UDSuffixToken;
    }
    /// Get the spelling offset of the first byte of the ud-suffix.
    unsigned getUDSuffixOffset() const {
      assert(!UDSuffixBuf.empty() && "no ud-suffix");
      return UDSuffixOffset;
    }
  
  private:
    void init(ArrayRef<Token> StringToks);
    bool CopyStringFragment(const Token &Tok, const char *TokBegin,
                            StringRef Fragment);
    void DiagnoseLexingError(SourceLocation Loc);
  };
  
  }  // end namespace clang
  
  #endif
  