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//===-- llvm/ADT/StringExtras.h - Useful string functions -------*- C++ -*-===//
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// The LLVM Compiler Infrastructure
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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// This file contains some functions that are useful when dealing with strings.
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ADT_STRINGEXTRAS_H
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#define LLVM_ADT_STRINGEXTRAS_H
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#include "llvm/System/DataTypes.h"
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#include "llvm/ADT/APFloat.h"
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#include "llvm/ADT/StringRef.h"
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template<typename T> class SmallVectorImpl;
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/// hexdigit - Return the (uppercase) hexadecimal character for the
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/// given number \arg X (which should be less than 16).
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static inline char hexdigit(unsigned X) {
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return X < 10 ? '0' + X : 'A' + X - 10;
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/// utohex_buffer - Emit the specified number into the buffer specified by
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/// BufferEnd, returning a pointer to the start of the string. This can be used
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/// like this: (note that the buffer must be large enough to handle any number):
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/// printf("0x%s", utohex_buffer(X, Buffer+40));
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/// This should only be used with unsigned types.
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template<typename IntTy>
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static inline char *utohex_buffer(IntTy X, char *BufferEnd) {
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char *BufPtr = BufferEnd;
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*--BufPtr = 0; // Null terminate buffer.
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*--BufPtr = '0'; // Handle special case.
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unsigned char Mod = static_cast<unsigned char>(X) & 15;
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*--BufPtr = hexdigit(Mod);
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static inline std::string utohexstr(uint64_t X) {
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return utohex_buffer(X, Buffer+40);
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static inline std::string utostr_32(uint32_t X, bool isNeg = false) {
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char *BufPtr = Buffer+19;
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*BufPtr = 0; // Null terminate buffer...
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if (X == 0) *--BufPtr = '0'; // Handle special case...
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*--BufPtr = '0' + char(X % 10);
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if (isNeg) *--BufPtr = '-'; // Add negative sign...
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return std::string(BufPtr);
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static inline std::string utostr(uint64_t X, bool isNeg = false) {
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return utostr_32(uint32_t(X), isNeg);
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char *BufPtr = Buffer+39;
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*BufPtr = 0; // Null terminate buffer...
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if (X == 0) *--BufPtr = '0'; // Handle special case...
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*--BufPtr = '0' + char(X % 10);
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if (isNeg) *--BufPtr = '-'; // Add negative sign...
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return std::string(BufPtr);
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static inline std::string itostr(int64_t X) {
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return utostr(static_cast<uint64_t>(-X), true);
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return utostr(static_cast<uint64_t>(X));
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static inline std::string ftostr(double V) {
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sprintf(Buffer, "%20.6e", V);
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while (*B == ' ') ++B;
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static inline std::string ftostr(const APFloat& V) {
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if (&V.getSemantics() == &APFloat::IEEEdouble)
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return ftostr(V.convertToDouble());
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else if (&V.getSemantics() == &APFloat::IEEEsingle)
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return ftostr((double)V.convertToFloat());
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return "<unknown format in ftostr>"; // error
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static inline std::string LowercaseString(const std::string &S) {
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std::string result(S);
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for (unsigned i = 0; i < S.length(); ++i)
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if (isupper(result[i]))
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result[i] = char(tolower(result[i]));
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static inline std::string UppercaseString(const std::string &S) {
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std::string result(S);
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for (unsigned i = 0; i < S.length(); ++i)
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if (islower(result[i]))
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result[i] = char(toupper(result[i]));
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/// StrInStrNoCase - Portable version of strcasestr. Locates the first
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/// occurrence of string 's1' in string 's2', ignoring case. Returns
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/// the offset of s2 in s1 or npos if s2 cannot be found.
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StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2);
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/// getToken - This function extracts one token from source, ignoring any
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/// leading characters that appear in the Delimiters string, and ending the
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/// token at any of the characters that appear in the Delimiters string. If
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/// there are no tokens in the source string, an empty string is returned.
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/// The function returns a pair containing the extracted token and the
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/// remaining tail string.
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std::pair<StringRef, StringRef> getToken(StringRef Source,
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StringRef Delimiters = " \t\n\v\f\r");
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/// SplitString - Split up the specified string according to the specified
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/// delimiters, appending the result fragments to the output list.
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void SplitString(StringRef Source,
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SmallVectorImpl<StringRef> &OutFragments,
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StringRef Delimiters = " \t\n\v\f\r");
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/// HashString - Hash funtion for strings.
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/// This is the Bernstein hash function.
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// FIXME: Investigate whether a modified bernstein hash function performs
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// better: http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
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static inline unsigned HashString(StringRef Str, unsigned Result = 0) {
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for (unsigned i = 0, e = Str.size(); i != e; ++i)
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Result = Result * 33 + Str[i];
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} // End llvm namespace