123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606 |
- //===--- 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 "Compiler.h"
- #include <algorithm>
- #include <cassert>
- #include <cstring>
- #include <limits>
- #include <string>
- #include <utility>
- namespace llvm {
- template <typename T>
- class SmallVectorImpl;
- class APInt;
- class hash_code;
- 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);
- /// 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:
- typedef const char *iterator;
- typedef const char *const_iterator;
- static const size_t npos = ~size_t(0);
- typedef size_t size_type;
- private:
- /// The start of the string, in an external buffer.
- const char *Data;
- /// The length of the string.
- size_t Length;
- // 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() : Data(nullptr), Length(0) {}
- /// Construct a string ref from a cstring.
- /*implicit*/ StringRef(const char *Str)
- : Data(Str) {
- assert(Str && "StringRef cannot be built from a NULL argument");
- Length = ::strlen(Str); // invoking strlen(NULL) is undefined behavior
- }
- /// Construct a string ref from a pointer and length.
- LLVM_ATTRIBUTE_ALWAYS_INLINE
- /*implicit*/ StringRef(const char *data, size_t length)
- : Data(data), Length(length) {
- assert((data || length == 0) &&
- "StringRef cannot be built from a NULL argument with non-null 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()) {}
- /// @}
- /// @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());
- }
- /// @}
- /// @name String Operations
- /// @{
- /// data - Get a pointer to the start of the string (which may not be null
- /// terminated).
- LLVM_ATTRIBUTE_ALWAYS_INLINE
- const char *data() const { return Data; }
- /// empty - Check if the string is empty.
- LLVM_ATTRIBUTE_ALWAYS_INLINE
- bool empty() const { return Length == 0; }
- /// size - Get the string size.
- LLVM_ATTRIBUTE_ALWAYS_INLINE
- size_t size() const { return Length; }
- /// front - Get the first character in the string.
- char front() const {
- assert(!empty());
- return Data[0];
- }
- /// back - Get the last character in the string.
- char back() const {
- assert(!empty());
- return Data[Length-1];
- }
- // copy - Allocate copy in Allocator and return StringRef to it.
- template <typename Allocator> StringRef copy(Allocator &A) const {
- 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_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.
- 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_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.
- int compare_lower(StringRef RHS) const;
- /// compare_numeric - Compare two strings, treating sequences of digits as
- /// numbers.
- 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.
- unsigned edit_distance(StringRef Other, bool AllowReplacements = true,
- unsigned MaxEditDistance = 0) const;
- /// str - Get the contents as an std::string.
- std::string str() const {
- if (!Data) return std::string();
- return std::string(Data, Length);
- }
- /// @}
- /// @name Operator Overloads
- /// @{
- char operator[](size_t Index) const {
- assert(Index < Length && "Invalid index!");
- return Data[Index];
- }
- /// @}
- /// @name Type Conversions
- /// @{
- operator std::string() const {
- return str();
- }
- /// @}
- /// @name String Predicates
- /// @{
- /// Check if this string starts with the given \p Prefix.
- 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.
- bool startswith_lower(StringRef Prefix) const;
- /// Check if this string ends with the given \p Suffix.
- 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.
- 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_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 (size_t)(static_cast<const char *>(P) - Data);
- }
- return npos;
- }
- /// 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.
- size_t find(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.
- 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 string \p Str in the string.
- ///
- /// \returns The index of the last occurrence of \p Str, or npos if not
- /// found.
- size_t rfind(StringRef Str) const;
- /// Find the first character in the string that is \p C, or npos if not
- /// found. Same as find.
- 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())
- 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.
- 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())
- 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.
- 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())
- 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.
- 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())
- size_t find_last_not_of(StringRef Chars, size_t From = npos) const;
- /// @}
- /// @name Helpful Algorithms
- /// @{
- /// Return the number of occurrences of \p C in the string.
- 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 \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;
- /// @}
- /// @name String Operations
- /// @{
- // Convert the given ASCII string to lowercase.
- std::string lower() const;
- /// Convert the given ASCII string to uppercase.
- 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_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 the first \p N elements
- /// dropped.
- 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_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 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 less than \p Start, or exceeds the
- /// number of characters remaining in the string, the string suffix
- /// (starting with \p Start) will be returned.
- 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.
- 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.
- 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.
- 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 characters in \p Chars starting from
- /// the left removed.
- 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 characters in \p Chars starting from
- /// the right removed.
- 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 characters in \p Chars starting from
- /// the left and right removed.
- StringRef trim(StringRef Chars = " \t\n\v\f\r") const {
- return ltrim(Chars).rtrim(Chars);
- }
- /// @}
- };
- /// @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.
- 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; };
- }
- #endif
|