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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