//===- StringRef.h - Constant String Reference Wrapper ----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_STRINGREF_H
#define LLVM_ADT_STRINGREF_H
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/Compiler.h"
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstring>
#include <limits>
#include <string>
#include <type_traits>
#include <utility>
namespace llvm {
class APInt;
class hash_code;
template <typename T> class SmallVectorImpl;
class StringRef;
/// Helper functions for StringRef::getAsInteger.
bool getAsUnsignedInteger(StringRef Str, unsigned Radix,
unsigned long long &Result);
bool getAsSignedInteger(StringRef Str, unsigned Radix, long long &Result);
bool consumeUnsignedInteger(StringRef &Str, unsigned Radix,
unsigned long long &Result);
bool consumeSignedInteger(StringRef &Str, unsigned Radix, long long &Result);
/// StringRef - Represent a constant reference to a string, i.e. a character
/// array and a length, which need not be null terminated.
///
/// This class does not own the string data, it is expected to be used in
/// situations where the character data resides in some other buffer, whose
/// lifetime extends past that of the StringRef. For this reason, it is not in
/// general safe to store a StringRef.
class StringRef {
public:
static const size_t npos = ~size_t(0);
using iterator = const char *;
using const_iterator = const char *;
using size_type = size_t;
private:
/// The start of the string, in an external buffer.
const char *Data = nullptr;
/// The length of the string.
size_t Length = 0;
// Workaround memcmp issue with null pointers (undefined behavior)
// by providing a specialized version
LLVM_ATTRIBUTE_ALWAYS_INLINE
static int compareMemory(const char *Lhs, const char *Rhs, size_t Length) {
if (Length == 0) { return 0; }
return ::memcmp(Lhs,Rhs,Length);
}
public:
/// @name Constructors
/// @{
/// Construct an empty string ref.
/*implicit*/ StringRef() = default;
/// Disable conversion from nullptr. This prevents things like
/// if (S == nullptr)
StringRef(std::nullptr_t) = delete;
/// Construct a string ref from a cstring.
LLVM_ATTRIBUTE_ALWAYS_INLINE
/*implicit*/ StringRef(const char *Str)
: Data(Str), Length(Str ? ::strlen(Str) : 0) {}
/// Construct a string ref from a pointer and length.
LLVM_ATTRIBUTE_ALWAYS_INLINE
/*implicit*/ constexpr StringRef(const char *data, size_t length)
: Data(data), Length(length) {}
/// Construct a string ref from an std::string.
LLVM_ATTRIBUTE_ALWAYS_INLINE
/*implicit*/ StringRef(const std::string &Str)
: Data(Str.data()), Length(Str.length()) {}
static StringRef withNullAsEmpty(const char *data) {
return StringRef(data ? data : "");
}
/// @}
/// @name Iterators
/// @{
iterator begin() const { return Data; }
iterator end() const { return Data + Length; }
const unsigned char *bytes_begin() const {
return reinterpret_cast<const unsigned char *>(begin());
}
const unsigned char *bytes_end() const {
return reinterpret_cast<const unsigned char *>(end());
}
iterator_range<const unsigned char *> bytes() const {
return make_range(bytes_begin(), bytes_end());
}
/// @}
/// @name String Operations
/// @{
/// data - Get a pointer to the start of the string (which may not be null
/// terminated).
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
const char *data() const { return Data; }
/// empty - Check if the string is empty.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
bool empty() const { return Length == 0; }
/// size - Get the string size.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
size_t size() const { return Length; }
/// front - Get the first character in the string.
LLVM_NODISCARD
char front() const {
assert(!empty());
return Data[0];
}
/// back - Get the last character in the string.
LLVM_NODISCARD
char back() const {
assert(!empty());
return Data[Length-1];
}
// copy - Allocate copy in Allocator and return StringRef to it.
template <typename Allocator>
LLVM_NODISCARD StringRef copy(Allocator &A) const {
// Don't request a length 0 copy from the allocator.
if (empty())
return StringRef();
char *S = A.template Allocate<char>(Length);
std::copy(begin(), end(), S);
return StringRef(S, Length);
}
/// equals - Check for string equality, this is more efficient than
/// compare() when the relative ordering of inequal strings isn't needed.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
bool equals(StringRef RHS) const {
return (Length == RHS.Length &&
compareMemory(Data, RHS.Data, RHS.Length) == 0);
}
/// equals_lower - Check for string equality, ignoring case.
LLVM_NODISCARD
bool equals_lower(StringRef RHS) const {
return Length == RHS.Length && compare_lower(RHS) == 0;
}
/// compare - Compare two strings; the result is -1, 0, or 1 if this string
/// is lexicographically less than, equal to, or greater than the \p RHS.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
int compare(StringRef RHS) const {
// Check the prefix for a mismatch.
if (int Res = compareMemory(Data, RHS.Data, std::min(Length, RHS.Length)))
return Res < 0 ? -1 : 1;
// Otherwise the prefixes match, so we only need to check the lengths.
if (Length == RHS.Length)
return 0;
return Length < RHS.Length ? -1 : 1;
}
/// compare_lower - Compare two strings, ignoring case.
LLVM_NODISCARD
int compare_lower(StringRef RHS) const;
/// compare_numeric - Compare two strings, treating sequences of digits as
/// numbers.
LLVM_NODISCARD
int compare_numeric(StringRef RHS) const;
/// \brief Determine the edit distance between this string and another
/// string.
///
/// \param Other the string to compare this string against.
///
/// \param AllowReplacements whether to allow character
/// replacements (change one character into another) as a single
/// operation, rather than as two operations (an insertion and a
/// removal).
///
/// \param MaxEditDistance If non-zero, the maximum edit distance that
/// this routine is allowed to compute. If the edit distance will exceed
/// that maximum, returns \c MaxEditDistance+1.
///
/// \returns the minimum number of character insertions, removals,
/// or (if \p AllowReplacements is \c true) replacements needed to
/// transform one of the given strings into the other. If zero,
/// the strings are identical.
LLVM_NODISCARD
unsigned edit_distance(StringRef Other, bool AllowReplacements = true,
unsigned MaxEditDistance = 0) const;
/// str - Get the contents as an std::string.
LLVM_NODISCARD
std::string str() const {
if (!Data) return std::string();
return std::string(Data, Length);
}
/// @}
/// @name Operator Overloads
/// @{
LLVM_NODISCARD
char operator[](size_t Index) const {
assert(Index < Length && "Invalid index!");
return Data[Index];
}
/// Disallow accidental assignment from a temporary std::string.
///
/// The declaration here is extra complicated so that `stringRef = {}`
/// and `stringRef = "abc"` continue to select the move assignment operator.
template <typename T>
typename std::enable_if<std::is_same<T, std::string>::value,
StringRef>::type &
operator=(T &&Str) = delete;
/// @}
/// @name Type Conversions
/// @{
operator std::string() const {
return str();
}
/// @}
/// @name String Predicates
/// @{
/// Check if this string starts with the given \p Prefix.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
bool startswith(StringRef Prefix) const {
return Length >= Prefix.Length &&
compareMemory(Data, Prefix.Data, Prefix.Length) == 0;
}
/// Check if this string starts with the given \p Prefix, ignoring case.
LLVM_NODISCARD
bool startswith_lower(StringRef Prefix) const;
/// Check if this string ends with the given \p Suffix.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
bool endswith(StringRef Suffix) const {
return Length >= Suffix.Length &&
compareMemory(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
}
/// Check if this string ends with the given \p Suffix, ignoring case.
LLVM_NODISCARD
bool endswith_lower(StringRef Suffix) const;
/// @}
/// @name String Searching
/// @{
/// Search for the first character \p C in the string.
///
/// \returns The index of the first occurrence of \p C, or npos if not
/// found.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
size_t find(char C, size_t From = 0) const {
size_t FindBegin = std::min(From, Length);
if (FindBegin < Length) { // Avoid calling memchr with nullptr.
// Just forward to memchr, which is faster than a hand-rolled loop.
if (const void *P = ::memchr(Data + FindBegin, C, Length - FindBegin))
return static_cast<const char *>(P) - Data;
}
return npos;
}
/// Search for the first character \p C in the string, ignoring case.
///
/// \returns The index of the first occurrence of \p C, or npos if not
/// found.
LLVM_NODISCARD
size_t find_lower(char C, size_t From = 0) const;
/// Search for the first character satisfying the predicate \p F
///
/// \returns The index of the first character satisfying \p F starting from
/// \p From, or npos if not found.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
size_t find_if(function_ref<bool(char)> F, size_t From = 0) const {
StringRef S = drop_front(From);
while (!S.empty()) {
if (F(S.front()))
return size() - S.size();
S = S.drop_front();
}
return npos;
}
/// Search for the first character not satisfying the predicate \p F
///
/// \returns The index of the first character not satisfying \p F starting
/// from \p From, or npos if not found.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
size_t find_if_not(function_ref<bool(char)> F, size_t From = 0) const {
return find_if([F](char c) { return !F(c); }, From);
}
/// Search for the first string \p Str in the string.
///
/// \returns The index of the first occurrence of \p Str, or npos if not
/// found.
LLVM_NODISCARD
size_t find(StringRef Str, size_t From = 0) const;
/// Search for the first string \p Str in the string, ignoring case.
///
/// \returns The index of the first occurrence of \p Str, or npos if not
/// found.
LLVM_NODISCARD
size_t find_lower(StringRef Str, size_t From = 0) const;
/// Search for the last character \p C in the string.
///
/// \returns The index of the last occurrence of \p C, or npos if not
/// found.
LLVM_NODISCARD
size_t rfind(char C, size_t From = npos) const {
From = std::min(From, Length);
size_t i = From;
while (i != 0) {
--i;
if (Data[i] == C)
return i;
}
return npos;
}
/// Search for the last character \p C in the string, ignoring case.
///
/// \returns The index of the last occurrence of \p C, or npos if not
/// found.
LLVM_NODISCARD
size_t rfind_lower(char C, size_t From = npos) const;
/// Search for the last string \p Str in the string.
///
/// \returns The index of the last occurrence of \p Str, or npos if not
/// found.
LLVM_NODISCARD
size_t rfind(StringRef Str) const;
/// Search for the last string \p Str in the string, ignoring case.
///
/// \returns The index of the last occurrence of \p Str, or npos if not
/// found.
LLVM_NODISCARD
size_t rfind_lower(StringRef Str) const;
/// Find the first character in the string that is \p C, or npos if not
/// found. Same as find.
LLVM_NODISCARD
size_t find_first_of(char C, size_t From = 0) const {
return find(C, From);
}
/// Find the first character in the string that is in \p Chars, or npos if
/// not found.
///
/// Complexity: O(size() + Chars.size())
LLVM_NODISCARD
size_t find_first_of(StringRef Chars, size_t From = 0) const;
/// Find the first character in the string that is not \p C or npos if not
/// found.
LLVM_NODISCARD
size_t find_first_not_of(char C, size_t From = 0) const;
/// Find the first character in the string that is not in the string
/// \p Chars, or npos if not found.
///
/// Complexity: O(size() + Chars.size())
LLVM_NODISCARD
size_t find_first_not_of(StringRef Chars, size_t From = 0) const;
/// Find the last character in the string that is \p C, or npos if not
/// found.
LLVM_NODISCARD
size_t find_last_of(char C, size_t From = npos) const {
return rfind(C, From);
}
/// Find the last character in the string that is in \p C, or npos if not
/// found.
///
/// Complexity: O(size() + Chars.size())
LLVM_NODISCARD
size_t find_last_of(StringRef Chars, size_t From = npos) const;
/// Find the last character in the string that is not \p C, or npos if not
/// found.
LLVM_NODISCARD
size_t find_last_not_of(char C, size_t From = npos) const;
/// Find the last character in the string that is not in \p Chars, or
/// npos if not found.
///
/// Complexity: O(size() + Chars.size())
LLVM_NODISCARD
size_t find_last_not_of(StringRef Chars, size_t From = npos) const;
/// Return true if the given string is a substring of *this, and false
/// otherwise.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
bool contains(StringRef Other) const { return find(Other) != npos; }
/// Return true if the given character is contained in *this, and false
/// otherwise.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
bool contains(char C) const { return find_first_of(C) != npos; }
/// Return true if the given string is a substring of *this, and false
/// otherwise.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
bool contains_lower(StringRef Other) const {
return find_lower(Other) != npos;
}
/// Return true if the given character is contained in *this, and false
/// otherwise.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
bool contains_lower(char C) const { return find_lower(C) != npos; }
/// @}
/// @name Helpful Algorithms
/// @{
/// Return the number of occurrences of \p C in the string.
LLVM_NODISCARD
size_t count(char C) const {
size_t Count = 0;
for (size_t i = 0, e = Length; i != e; ++i)
if (Data[i] == C)
++Count;
return Count;
}
/// Return the number of non-overlapped occurrences of \p Str in
/// the string.
size_t count(StringRef Str) const;
/// Parse the current string as an integer of the specified radix. If
/// \p Radix is specified as zero, this does radix autosensing using
/// extended C rules: 0 is octal, 0x is hex, 0b is binary.
///
/// If the string is invalid or if only a subset of the string is valid,
/// this returns true to signify the error. The string is considered
/// erroneous if empty or if it overflows T.
template <typename T>
typename std::enable_if<std::numeric_limits<T>::is_signed, bool>::type
getAsInteger(unsigned Radix, T &Result) const {
long long LLVal;
if (getAsSignedInteger(*this, Radix, LLVal) ||
static_cast<T>(LLVal) != LLVal)
return true;
Result = LLVal;
return false;
}
template <typename T>
typename std::enable_if<!std::numeric_limits<T>::is_signed, bool>::type
getAsInteger(unsigned Radix, T &Result) const {
unsigned long long ULLVal;
// The additional cast to unsigned long long is required to avoid the
// Visual C++ warning C4805: '!=' : unsafe mix of type 'bool' and type
// 'unsigned __int64' when instantiating getAsInteger with T = bool.
if (getAsUnsignedInteger(*this, Radix, ULLVal) ||
static_cast<unsigned long long>(static_cast<T>(ULLVal)) != ULLVal)
return true;
Result = ULLVal;
return false;
}
/// Parse the current string as an integer of the specified radix. If
/// \p Radix is specified as zero, this does radix autosensing using
/// extended C rules: 0 is octal, 0x is hex, 0b is binary.
///
/// If the string does not begin with a number of the specified radix,
/// this returns true to signify the error. The string is considered
/// erroneous if empty or if it overflows T.
/// The portion of the string representing the discovered numeric value
/// is removed from the beginning of the string.
template <typename T>
typename std::enable_if<std::numeric_limits<T>::is_signed, bool>::type
consumeInteger(unsigned Radix, T &Result) {
long long LLVal;
if (consumeSignedInteger(*this, Radix, LLVal) ||
static_cast<long long>(static_cast<T>(LLVal)) != LLVal)
return true;
Result = LLVal;
return false;
}
template <typename T>
typename std::enable_if<!std::numeric_limits<T>::is_signed, bool>::type
consumeInteger(unsigned Radix, T &Result) {
unsigned long long ULLVal;
if (consumeUnsignedInteger(*this, Radix, ULLVal) ||
static_cast<unsigned long long>(static_cast<T>(ULLVal)) != ULLVal)
return true;
Result = ULLVal;
return false;
}
/// Parse the current string as an integer of the specified \p Radix, or of
/// an autosensed radix if the \p Radix given is 0. The current value in
/// \p Result is discarded, and the storage is changed to be wide enough to
/// store the parsed integer.
///
/// \returns true if the string does not solely consist of a valid
/// non-empty number in the appropriate base.
///
/// APInt::fromString is superficially similar but assumes the
/// string is well-formed in the given radix.
bool getAsInteger(unsigned Radix, APInt &Result) const;
/// Parse the current string as an IEEE double-precision floating
/// point value. The string must be a well-formed double.
///
/// If \p AllowInexact is false, the function will fail if the string
/// cannot be represented exactly. Otherwise, the function only fails
/// in case of an overflow or underflow.
bool getAsDouble(double &Result, bool AllowInexact = true) const;
/// @}
/// @name String Operations
/// @{
// Convert the given ASCII string to lowercase.
LLVM_NODISCARD
std::string lower() const;
/// Convert the given ASCII string to uppercase.
LLVM_NODISCARD
std::string upper() const;
/// @}
/// @name Substring Operations
/// @{
/// Return a reference to the substring from [Start, Start + N).
///
/// \param Start The index of the starting character in the substring; if
/// the index is npos or greater than the length of the string then the
/// empty substring will be returned.
///
/// \param N The number of characters to included in the substring. If N
/// exceeds the number of characters remaining in the string, the string
/// suffix (starting with \p Start) will be returned.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
StringRef substr(size_t Start, size_t N = npos) const {
Start = std::min(Start, Length);
return StringRef(Data + Start, std::min(N, Length - Start));
}
/// Return a StringRef equal to 'this' but with only the first \p N
/// elements remaining. If \p N is greater than the length of the
/// string, the entire string is returned.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
StringRef take_front(size_t N = 1) const {
if (N >= size())
return *this;
return drop_back(size() - N);
}
/// Return a StringRef equal to 'this' but with only the last \p N
/// elements remaining. If \p N is greater than the length of the
/// string, the entire string is returned.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
StringRef take_back(size_t N = 1) const {
if (N >= size())
return *this;
return drop_front(size() - N);
}
/// Return the longest prefix of 'this' such that every character
/// in the prefix satisfies the given predicate.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
StringRef take_while(function_ref<bool(char)> F) const {
return substr(0, find_if_not(F));
}
/// Return the longest prefix of 'this' such that no character in
/// the prefix satisfies the given predicate.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
StringRef take_until(function_ref<bool(char)> F) const {
return substr(0, find_if(F));
}
/// Return a StringRef equal to 'this' but with the first \p N elements
/// dropped.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
StringRef drop_front(size_t N = 1) const {
assert(size() >= N && "Dropping more elements than exist");
return substr(N);
}
/// Return a StringRef equal to 'this' but with the last \p N elements
/// dropped.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
StringRef drop_back(size_t N = 1) const {
assert(size() >= N && "Dropping more elements than exist");
return substr(0, size()-N);
}
/// Return a StringRef equal to 'this', but with all characters satisfying
/// the given predicate dropped from the beginning of the string.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
StringRef drop_while(function_ref<bool(char)> F) const {
return substr(find_if_not(F));
}
/// Return a StringRef equal to 'this', but with all characters not
/// satisfying the given predicate dropped from the beginning of the string.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
StringRef drop_until(function_ref<bool(char)> F) const {
return substr(find_if(F));
}
/// Returns true if this StringRef has the given prefix and removes that
/// prefix.
LLVM_ATTRIBUTE_ALWAYS_INLINE
bool consume_front(StringRef Prefix) {
if (!startswith(Prefix))
return false;
*this = drop_front(Prefix.size());
return true;
}
/// Returns true if this StringRef has the given suffix and removes that
/// suffix.
LLVM_ATTRIBUTE_ALWAYS_INLINE
bool consume_back(StringRef Suffix) {
if (!endswith(Suffix))
return false;
*this = drop_back(Suffix.size());
return true;
}
/// Return a reference to the substring from [Start, End).
///
/// \param Start The index of the starting character in the substring; if
/// the index is npos or greater than the length of the string then the
/// empty substring will be returned.
///
/// \param End The index following the last character to include in the
/// substring. If this is npos or exceeds the number of characters
/// remaining in the string, the string suffix (starting with \p Start)
/// will be returned. If this is less than \p Start, an empty string will
/// be returned.
LLVM_NODISCARD
LLVM_ATTRIBUTE_ALWAYS_INLINE
StringRef slice(size_t Start, size_t End) const {
Start = std::min(Start, Length);
End = std::min(std::max(Start, End), Length);
return StringRef(Data + Start, End - Start);
}
/// Split into two substrings around the first occurrence of a separator
/// character.
///
/// If \p Separator is in the string, then the result is a pair (LHS, RHS)
/// such that (*this == LHS + Separator + RHS) is true and RHS is
/// maximal. If \p Separator is not in the string, then the result is a
/// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
///
/// \param Separator The character to split on.
/// \returns The split substrings.
LLVM_NODISCARD
std::pair<StringRef, StringRef> split(char Separator) const {
size_t Idx = find(Separator);
if (Idx == npos)
return std::make_pair(*this, StringRef());
return std::make_pair(slice(0, Idx), slice(Idx+1, npos));
}
/// Split into two substrings around the first occurrence of a separator
/// string.
///
/// If \p Separator is in the string, then the result is a pair (LHS, RHS)
/// such that (*this == LHS + Separator + RHS) is true and RHS is
/// maximal. If \p Separator is not in the string, then the result is a
/// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
///
/// \param Separator - The string to split on.
/// \return - The split substrings.
LLVM_NODISCARD
std::pair<StringRef, StringRef> split(StringRef Separator) const {
size_t Idx = find(Separator);
if (Idx == npos)
return std::make_pair(*this, StringRef());
return std::make_pair(slice(0, Idx), slice(Idx + Separator.size(), npos));
}
/// Split into substrings around the occurrences of a separator string.
///
/// Each substring is stored in \p A. If \p MaxSplit is >= 0, at most
/// \p MaxSplit splits are done and consequently <= \p MaxSplit + 1
/// elements are added to A.
/// If \p KeepEmpty is false, empty strings are not added to \p A. They
/// still count when considering \p MaxSplit
/// An useful invariant is that
/// Separator.join(A) == *this if MaxSplit == -1 and KeepEmpty == true
///
/// \param A - Where to put the substrings.
/// \param Separator - The string to split on.
/// \param MaxSplit - The maximum number of times the string is split.
/// \param KeepEmpty - True if empty substring should be added.
void split(SmallVectorImpl<StringRef> &A,
StringRef Separator, int MaxSplit = -1,
bool KeepEmpty = true) const;
/// Split into substrings around the occurrences of a separator character.
///
/// Each substring is stored in \p A. If \p MaxSplit is >= 0, at most
/// \p MaxSplit splits are done and consequently <= \p MaxSplit + 1
/// elements are added to A.
/// If \p KeepEmpty is false, empty strings are not added to \p A. They
/// still count when considering \p MaxSplit
/// An useful invariant is that
/// Separator.join(A) == *this if MaxSplit == -1 and KeepEmpty == true
///
/// \param A - Where to put the substrings.
/// \param Separator - The string to split on.
/// \param MaxSplit - The maximum number of times the string is split.
/// \param KeepEmpty - True if empty substring should be added.
void split(SmallVectorImpl<StringRef> &A, char Separator, int MaxSplit = -1,
bool KeepEmpty = true) const;
/// Split into two substrings around the last occurrence of a separator
/// character.
///
/// If \p Separator is in the string, then the result is a pair (LHS, RHS)
/// such that (*this == LHS + Separator + RHS) is true and RHS is
/// minimal. If \p Separator is not in the string, then the result is a
/// pair (LHS, RHS) where (*this == LHS) and (RHS == "").
///
/// \param Separator - The character to split on.
/// \return - The split substrings.
LLVM_NODISCARD
std::pair<StringRef, StringRef> rsplit(char Separator) const {
size_t Idx = rfind(Separator);
if (Idx == npos)
return std::make_pair(*this, StringRef());
return std::make_pair(slice(0, Idx), slice(Idx+1, npos));
}
/// Return string with consecutive \p Char characters starting from the
/// the left removed.
LLVM_NODISCARD
StringRef ltrim(char Char) const {
return drop_front(std::min(Length, find_first_not_of(Char)));
}
/// Return string with consecutive characters in \p Chars starting from
/// the left removed.
LLVM_NODISCARD
StringRef ltrim(StringRef Chars = " \t\n\v\f\r") const {
return drop_front(std::min(Length, find_first_not_of(Chars)));
}
/// Return string with consecutive \p Char characters starting from the
/// right removed.
LLVM_NODISCARD
StringRef rtrim(char Char) const {
return drop_back(Length - std::min(Length, find_last_not_of(Char) + 1));
}
/// Return string with consecutive characters in \p Chars starting from
/// the right removed.
LLVM_NODISCARD
StringRef rtrim(StringRef Chars = " \t\n\v\f\r") const {
return drop_back(Length - std::min(Length, find_last_not_of(Chars) + 1));
}
/// Return string with consecutive \p Char characters starting from the
/// left and right removed.
LLVM_NODISCARD
StringRef trim(char Char) const {
return ltrim(Char).rtrim(Char);
}
/// Return string with consecutive characters in \p Chars starting from
/// the left and right removed.
LLVM_NODISCARD
StringRef trim(StringRef Chars = " \t\n\v\f\r") const {
return ltrim(Chars).rtrim(Chars);
}
/// @}
};
/// A wrapper around a string literal that serves as a proxy for constructing
/// global tables of StringRefs with the length computed at compile time.
/// In order to avoid the invocation of a global constructor, StringLiteral
/// should *only* be used in a constexpr context, as such:
///
/// constexpr StringLiteral S("test");
///
class StringLiteral : public StringRef {
public:
template <size_t N>
constexpr StringLiteral(const char (&Str)[N])
#if defined(__clang__) && __has_attribute(enable_if)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wgcc-compat"
__attribute((enable_if(__builtin_strlen(Str) == N - 1,
"invalid string literal")))
#pragma clang diagnostic pop
#endif
: StringRef(Str, N - 1) {
}
};
/// @name StringRef Comparison Operators
/// @{
LLVM_ATTRIBUTE_ALWAYS_INLINE
inline bool operator==(StringRef LHS, StringRef RHS) {
return LHS.equals(RHS);
}
LLVM_ATTRIBUTE_ALWAYS_INLINE
inline bool operator!=(StringRef LHS, StringRef RHS) { return !(LHS == RHS); }
inline bool operator<(StringRef LHS, StringRef RHS) {
return LHS.compare(RHS) == -1;
}
inline bool operator<=(StringRef LHS, StringRef RHS) {
return LHS.compare(RHS) != 1;
}
inline bool operator>(StringRef LHS, StringRef RHS) {
return LHS.compare(RHS) == 1;
}
inline bool operator>=(StringRef LHS, StringRef RHS) {
return LHS.compare(RHS) != -1;
}
inline std::string &operator+=(std::string &buffer, StringRef string) {
return buffer.append(string.data(), string.size());
}
/// @}
/// \brief Compute a hash_code for a StringRef.
LLVM_NODISCARD
hash_code hash_value(StringRef S);
// StringRefs can be treated like a POD type.
template <typename T> struct isPodLike;
template <> struct isPodLike<StringRef> { static const bool value = true; };
} // end namespace llvm
#endif // LLVM_ADT_STRINGREF_H