1 //===- llvm/ADT/StringExtras.h - Useful string functions --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains some functions that are useful when dealing with strings.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ADT_STRINGEXTRAS_H
15 #define LLVM_ADT_STRINGEXTRAS_H
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/ADT/Twine.h"
32 template<typename T> class SmallVectorImpl;
35 /// hexdigit - Return the hexadecimal character for the
36 /// given number \p X (which should be less than 16).
37 inline char hexdigit(unsigned X, bool LowerCase = false) {
38 const char HexChar = LowerCase ? 'a' : 'A';
39 return X < 10 ? '0' + X : HexChar + X - 10;
42 /// Construct a string ref from a boolean.
43 inline StringRef toStringRef(bool B) { return StringRef(B ? "true" : "false"); }
45 /// Construct a string ref from an array ref of unsigned chars.
46 inline StringRef toStringRef(ArrayRef<uint8_t> Input) {
47 return StringRef(reinterpret_cast<const char *>(Input.begin()), Input.size());
50 /// Construct a string ref from an array ref of unsigned chars.
51 inline ArrayRef<uint8_t> arrayRefFromStringRef(StringRef Input) {
52 return {Input.bytes_begin(), Input.bytes_end()};
55 /// Interpret the given character \p C as a hexadecimal digit and return its
58 /// If \p C is not a valid hex digit, -1U is returned.
59 inline unsigned hexDigitValue(char C) {
60 if (C >= '0' && C <= '9') return C-'0';
61 if (C >= 'a' && C <= 'f') return C-'a'+10U;
62 if (C >= 'A' && C <= 'F') return C-'A'+10U;
66 /// Checks if character \p C is one of the 10 decimal digits.
67 inline bool isDigit(char C) { return C >= '0' && C <= '9'; }
69 /// Checks if character \p C is a hexadecimal numeric character.
70 inline bool isHexDigit(char C) { return hexDigitValue(C) != -1U; }
72 /// Checks if character \p C is a valid letter as classified by "C" locale.
73 inline bool isAlpha(char C) {
74 return ('a' <= C && C <= 'z') || ('A' <= C && C <= 'Z');
77 /// Checks whether character \p C is either a decimal digit or an uppercase or
78 /// lowercase letter as classified by "C" locale.
79 inline bool isAlnum(char C) { return isAlpha(C) || isDigit(C); }
81 /// Returns the corresponding lowercase character if \p x is uppercase.
82 inline char toLower(char x) {
83 if (x >= 'A' && x <= 'Z')
88 /// Returns the corresponding uppercase character if \p x is lowercase.
89 inline char toUpper(char x) {
90 if (x >= 'a' && x <= 'z')
95 inline std::string utohexstr(uint64_t X, bool LowerCase = false) {
97 char *BufPtr = std::end(Buffer);
99 if (X == 0) *--BufPtr = '0';
102 unsigned char Mod = static_cast<unsigned char>(X) & 15;
103 *--BufPtr = hexdigit(Mod, LowerCase);
107 return std::string(BufPtr, std::end(Buffer));
110 /// Convert buffer \p Input to its hexadecimal representation.
111 /// The returned string is double the size of \p Input.
112 inline std::string toHex(StringRef Input) {
113 static const char *const LUT = "0123456789ABCDEF";
114 size_t Length = Input.size();
117 Output.reserve(2 * Length);
118 for (size_t i = 0; i < Length; ++i) {
119 const unsigned char c = Input[i];
120 Output.push_back(LUT[c >> 4]);
121 Output.push_back(LUT[c & 15]);
126 inline std::string toHex(ArrayRef<uint8_t> Input) {
127 return toHex(toStringRef(Input));
130 inline uint8_t hexFromNibbles(char MSB, char LSB) {
131 unsigned U1 = hexDigitValue(MSB);
132 unsigned U2 = hexDigitValue(LSB);
133 assert(U1 != -1U && U2 != -1U);
135 return static_cast<uint8_t>((U1 << 4) | U2);
138 /// Convert hexadecimal string \p Input to its binary representation.
139 /// The return string is half the size of \p Input.
140 inline std::string fromHex(StringRef Input) {
142 return std::string();
145 Output.reserve((Input.size() + 1) / 2);
146 if (Input.size() % 2 == 1) {
147 Output.push_back(hexFromNibbles('0', Input.front()));
148 Input = Input.drop_front();
151 assert(Input.size() % 2 == 0);
152 while (!Input.empty()) {
153 uint8_t Hex = hexFromNibbles(Input[0], Input[1]);
154 Output.push_back(Hex);
155 Input = Input.drop_front(2);
160 /// \brief Convert the string \p S to an integer of the specified type using
161 /// the radix \p Base. If \p Base is 0, auto-detects the radix.
162 /// Returns true if the number was successfully converted, false otherwise.
163 template <typename N> bool to_integer(StringRef S, N &Num, unsigned Base = 0) {
164 return !S.getAsInteger(Base, Num);
168 template <typename N>
169 inline bool to_float(const Twine &T, N &Num, N (*StrTo)(const char *, char **)) {
170 SmallString<32> Storage;
171 StringRef S = T.toNullTerminatedStringRef(Storage);
173 N Temp = StrTo(S.data(), &End);
181 inline bool to_float(const Twine &T, float &Num) {
182 return detail::to_float(T, Num, strtof);
185 inline bool to_float(const Twine &T, double &Num) {
186 return detail::to_float(T, Num, strtod);
189 inline bool to_float(const Twine &T, long double &Num) {
190 return detail::to_float(T, Num, strtold);
193 inline std::string utostr(uint64_t X, bool isNeg = false) {
195 char *BufPtr = std::end(Buffer);
197 if (X == 0) *--BufPtr = '0'; // Handle special case...
200 *--BufPtr = '0' + char(X % 10);
204 if (isNeg) *--BufPtr = '-'; // Add negative sign...
205 return std::string(BufPtr, std::end(Buffer));
208 inline std::string itostr(int64_t X) {
210 return utostr(static_cast<uint64_t>(-X), true);
212 return utostr(static_cast<uint64_t>(X));
215 /// StrInStrNoCase - Portable version of strcasestr. Locates the first
216 /// occurrence of string 's1' in string 's2', ignoring case. Returns
217 /// the offset of s2 in s1 or npos if s2 cannot be found.
218 StringRef::size_type StrInStrNoCase(StringRef s1, StringRef s2);
220 /// getToken - This function extracts one token from source, ignoring any
221 /// leading characters that appear in the Delimiters string, and ending the
222 /// token at any of the characters that appear in the Delimiters string. If
223 /// there are no tokens in the source string, an empty string is returned.
224 /// The function returns a pair containing the extracted token and the
225 /// remaining tail string.
226 std::pair<StringRef, StringRef> getToken(StringRef Source,
227 StringRef Delimiters = " \t\n\v\f\r");
229 /// SplitString - Split up the specified string according to the specified
230 /// delimiters, appending the result fragments to the output list.
231 void SplitString(StringRef Source,
232 SmallVectorImpl<StringRef> &OutFragments,
233 StringRef Delimiters = " \t\n\v\f\r");
235 /// HashString - Hash function for strings.
237 /// This is the Bernstein hash function.
239 // FIXME: Investigate whether a modified bernstein hash function performs
240 // better: http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx
242 inline unsigned HashString(StringRef Str, unsigned Result = 0) {
243 for (StringRef::size_type i = 0, e = Str.size(); i != e; ++i)
244 Result = Result * 33 + (unsigned char)Str[i];
248 /// Returns the English suffix for an ordinal integer (-st, -nd, -rd, -th).
249 inline StringRef getOrdinalSuffix(unsigned Val) {
250 // It is critically important that we do this perfectly for
251 // user-written sequences with over 100 elements.
262 default: return "th";
267 /// PrintEscapedString - Print each character of the specified string, escaping
268 /// it if it is not printable or if it is an escape char.
269 void PrintEscapedString(StringRef Name, raw_ostream &Out);
271 /// printLowerCase - Print each character as lowercase if it is uppercase.
272 void printLowerCase(StringRef String, raw_ostream &Out);
276 template <typename IteratorT>
277 inline std::string join_impl(IteratorT Begin, IteratorT End,
278 StringRef Separator, std::input_iterator_tag) {
284 while (++Begin != End) {
291 template <typename IteratorT>
292 inline std::string join_impl(IteratorT Begin, IteratorT End,
293 StringRef Separator, std::forward_iterator_tag) {
298 size_t Len = (std::distance(Begin, End) - 1) * Separator.size();
299 for (IteratorT I = Begin; I != End; ++I)
300 Len += (*Begin).size();
303 while (++Begin != End) {
310 template <typename Sep>
311 inline void join_items_impl(std::string &Result, Sep Separator) {}
313 template <typename Sep, typename Arg>
314 inline void join_items_impl(std::string &Result, Sep Separator,
319 template <typename Sep, typename Arg1, typename... Args>
320 inline void join_items_impl(std::string &Result, Sep Separator, const Arg1 &A1,
324 join_items_impl(Result, Separator, std::forward<Args>(Items)...);
327 inline size_t join_one_item_size(char C) { return 1; }
328 inline size_t join_one_item_size(const char *S) { return S ? ::strlen(S) : 0; }
330 template <typename T> inline size_t join_one_item_size(const T &Str) {
334 inline size_t join_items_size() { return 0; }
336 template <typename A1> inline size_t join_items_size(const A1 &A) {
337 return join_one_item_size(A);
339 template <typename A1, typename... Args>
340 inline size_t join_items_size(const A1 &A, Args &&... Items) {
341 return join_one_item_size(A) + join_items_size(std::forward<Args>(Items)...);
344 } // end namespace detail
346 /// Joins the strings in the range [Begin, End), adding Separator between
348 template <typename IteratorT>
349 inline std::string join(IteratorT Begin, IteratorT End, StringRef Separator) {
350 using tag = typename std::iterator_traits<IteratorT>::iterator_category;
351 return detail::join_impl(Begin, End, Separator, tag());
354 /// Joins the strings in the range [R.begin(), R.end()), adding Separator
355 /// between the elements.
356 template <typename Range>
357 inline std::string join(Range &&R, StringRef Separator) {
358 return join(R.begin(), R.end(), Separator);
361 /// Joins the strings in the parameter pack \p Items, adding \p Separator
362 /// between the elements. All arguments must be implicitly convertible to
363 /// std::string, or there should be an overload of std::string::operator+=()
364 /// that accepts the argument explicitly.
365 template <typename Sep, typename... Args>
366 inline std::string join_items(Sep Separator, Args &&... Items) {
368 if (sizeof...(Items) == 0)
371 size_t NS = detail::join_one_item_size(Separator);
372 size_t NI = detail::join_items_size(std::forward<Args>(Items)...);
373 Result.reserve(NI + (sizeof...(Items) - 1) * NS + 1);
374 detail::join_items_impl(Result, Separator, std::forward<Args>(Items)...);
378 } // end namespace llvm
380 #endif // LLVM_ADT_STRINGEXTRAS_H