llvm-6502/include/llvm/ADT/StringRef.h
Jakob Stoklund Olesen 160a3bf74d Add StringRef::compare_numeric and use it to sort TableGen register records.
This means that our Registers are now ordered R7, R8, R9, R10, R12, ...
Not R1, R10, R11, R12, R2, R3, ...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104745 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-26 21:47:28 +00:00

433 lines
15 KiB
C++

//===--- 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 <cassert>
#include <cstring>
#include <utility>
#include <string>
namespace llvm {
template<typename T>
class SmallVectorImpl;
class APInt;
/// 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 PR5482: nearly all gcc 4.x miscompile StringRef and std::min()
// Changing the arg of min to be an integer, instead of a reference to an
// integer works around this bug.
static size_t min(size_t a, size_t b) { return a < b ? a : b; }
static size_t max(size_t a, size_t b) { return a > b ? a : b; }
public:
/// @name Constructors
/// @{
/// Construct an empty string ref.
/*implicit*/ StringRef() : Data(0), Length(0) {}
/// Construct a string ref from a cstring.
/*implicit*/ StringRef(const char *Str)
: Data(Str), Length(::strlen(Str)) {}
/// Construct a string ref from a pointer and length.
/*implicit*/ StringRef(const char *data, size_t length)
: Data(data), Length(length) {}
/// Construct a string ref from an std::string.
/*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; }
/// @}
/// @name String Operations
/// @{
/// data - Get a pointer to the start of the string (which may not be null
/// terminated).
const char *data() const { return Data; }
/// empty - Check if the string is empty.
bool empty() const { return Length == 0; }
/// size - Get the string size.
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];
}
/// equals - Check for string equality, this is more efficient than
/// compare() when the relative ordering of inequal strings isn't needed.
bool equals(StringRef RHS) const {
return (Length == RHS.Length &&
memcmp(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 \arg RHS.
int compare(StringRef RHS) const {
// Check the prefix for a mismatch.
if (int Res = memcmp(Data, RHS.Data, 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).
///
/// \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);
/// str - Get the contents as an std::string.
std::string str() const { 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
/// @{
/// startswith - Check if this string starts with the given \arg Prefix.
bool startswith(StringRef Prefix) const {
return Length >= Prefix.Length &&
memcmp(Data, Prefix.Data, Prefix.Length) == 0;
}
/// endswith - Check if this string ends with the given \arg Suffix.
bool endswith(StringRef Suffix) const {
return Length >= Suffix.Length &&
memcmp(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
}
/// @}
/// @name String Searching
/// @{
/// find - Search for the first character \arg C in the string.
///
/// \return - The index of the first occurrence of \arg C, or npos if not
/// found.
size_t find(char C, size_t From = 0) const {
for (size_t i = min(From, Length), e = Length; i != e; ++i)
if (Data[i] == C)
return i;
return npos;
}
/// find - Search for the first string \arg Str in the string.
///
/// \return - The index of the first occurrence of \arg Str, or npos if not
/// found.
size_t find(StringRef Str, size_t From = 0) const;
/// rfind - Search for the last character \arg C in the string.
///
/// \return - The index of the last occurrence of \arg C, or npos if not
/// found.
size_t rfind(char C, size_t From = npos) const {
From = min(From, Length);
size_t i = From;
while (i != 0) {
--i;
if (Data[i] == C)
return i;
}
return npos;
}
/// rfind - Search for the last string \arg Str in the string.
///
/// \return - The index of the last occurrence of \arg Str, or npos if not
/// found.
size_t rfind(StringRef Str) const;
/// find_first_of - Find the first character in the string that is \arg C,
/// or npos if not found. Same as find.
size_type find_first_of(char C, size_t = 0) const { return find(C); }
/// find_first_of - Find the first character in the string that is in \arg
/// Chars, or npos if not found.
///
/// Note: O(size() * Chars.size())
size_type find_first_of(StringRef Chars, size_t From = 0) const;
/// find_first_not_of - Find the first character in the string that is not
/// \arg C or npos if not found.
size_type find_first_not_of(char C, size_t From = 0) const;
/// find_first_not_of - Find the first character in the string that is not
/// in the string \arg Chars, or npos if not found.
///
/// Note: O(size() * Chars.size())
size_type find_first_not_of(StringRef Chars, size_t From = 0) const;
/// @}
/// @name Helpful Algorithms
/// @{
/// count - Return the number of occurrences of \arg 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;
}
/// count - Return the number of non-overlapped occurrences of \arg Str in
/// the string.
size_t count(StringRef Str) const;
/// getAsInteger - Parse the current string as an integer of the specified
/// radix. If 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.
///
bool getAsInteger(unsigned Radix, long long &Result) const;
bool getAsInteger(unsigned Radix, unsigned long long &Result) const;
bool getAsInteger(unsigned Radix, int &Result) const;
bool getAsInteger(unsigned Radix, unsigned &Result) const;
// TODO: Provide overloads for int/unsigned that check for overflow.
/// getAsInteger - Parse the current string as an integer of the
/// specified radix, or of an autosensed radix if the radix given
/// is 0. The current value in 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 Substring Operations
/// @{
/// substr - 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 \arg Start) will be returned.
StringRef substr(size_t Start, size_t N = npos) const {
Start = min(Start, Length);
return StringRef(Data + Start, min(N, Length - Start));
}
/// slice - 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 \arg Start, or exceeds the
/// number of characters remaining in the string, the string suffix
/// (starting with \arg Start) will be returned.
StringRef slice(size_t Start, size_t End) const {
Start = min(Start, Length);
End = min(max(Start, End), Length);
return StringRef(Data + Start, End - Start);
}
/// split - Split into two substrings around the first occurrence of a
/// separator character.
///
/// If \arg 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 \arg 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> 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 - Split into two substrings around the first occurrence of a
/// separator string.
///
/// If \arg 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 \arg 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 - Split into substrings around the occurrences of a separator
/// string.
///
/// Each substring is stored in \arg A. If \arg MaxSplit is >= 0, at most
/// \arg MaxSplit splits are done and consequently <= \arg MaxSplit
/// elements are added to A.
/// If \arg KeepEmpty is false, empty strings are not added to \arg A. They
/// still count when considering \arg 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;
/// rsplit - Split into two substrings around the last occurrence of a
/// separator character.
///
/// If \arg 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 \arg 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));
}
/// @}
};
/// @name StringRef Comparison Operators
/// @{
inline bool operator==(StringRef LHS, StringRef RHS) {
return LHS.equals(RHS);
}
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;
}
/// @}
}
#endif