llvm-project/llvm/lib/Support/StringRef.cpp

609 lines
18 KiB
C++

//===-- StringRef.cpp - Lightweight String References ---------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/edit_distance.h"
#include "llvm/Support/Error.h"
#include <bitset>
using namespace llvm;
// MSVC emits references to this into the translation units which reference it.
#ifndef _MSC_VER
const size_t StringRef::npos;
#endif
// strncasecmp() is not available on non-POSIX systems, so define an
// alternative function here.
static int ascii_strncasecmp(const char *LHS, const char *RHS, size_t Length) {
for (size_t I = 0; I < Length; ++I) {
unsigned char LHC = toLower(LHS[I]);
unsigned char RHC = toLower(RHS[I]);
if (LHC != RHC)
return LHC < RHC ? -1 : 1;
}
return 0;
}
/// compare_lower - Compare strings, ignoring case.
int StringRef::compare_lower(StringRef RHS) const {
if (int Res = ascii_strncasecmp(Data, RHS.Data, std::min(Length, RHS.Length)))
return Res;
if (Length == RHS.Length)
return 0;
return Length < RHS.Length ? -1 : 1;
}
/// Check if this string starts with the given \p Prefix, ignoring case.
bool StringRef::startswith_lower(StringRef Prefix) const {
return Length >= Prefix.Length &&
ascii_strncasecmp(Data, Prefix.Data, Prefix.Length) == 0;
}
/// Check if this string ends with the given \p Suffix, ignoring case.
bool StringRef::endswith_lower(StringRef Suffix) const {
return Length >= Suffix.Length &&
ascii_strncasecmp(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
}
size_t StringRef::find_lower(char C, size_t From) const {
char L = toLower(C);
return find_if([L](char D) { return toLower(D) == L; }, From);
}
/// compare_numeric - Compare strings, handle embedded numbers.
int StringRef::compare_numeric(StringRef RHS) const {
for (size_t I = 0, E = std::min(Length, RHS.Length); I != E; ++I) {
// Check for sequences of digits.
if (isDigit(Data[I]) && isDigit(RHS.Data[I])) {
// The longer sequence of numbers is considered larger.
// This doesn't really handle prefixed zeros well.
size_t J;
for (J = I + 1; J != E + 1; ++J) {
bool ld = J < Length && isDigit(Data[J]);
bool rd = J < RHS.Length && isDigit(RHS.Data[J]);
if (ld != rd)
return rd ? -1 : 1;
if (!rd)
break;
}
// The two number sequences have the same length (J-I), just memcmp them.
if (int Res = compareMemory(Data + I, RHS.Data + I, J - I))
return Res < 0 ? -1 : 1;
// Identical number sequences, continue search after the numbers.
I = J - 1;
continue;
}
if (Data[I] != RHS.Data[I])
return (unsigned char)Data[I] < (unsigned char)RHS.Data[I] ? -1 : 1;
}
if (Length == RHS.Length)
return 0;
return Length < RHS.Length ? -1 : 1;
}
// Compute the edit distance between the two given strings.
unsigned StringRef::edit_distance(llvm::StringRef Other,
bool AllowReplacements,
unsigned MaxEditDistance) const {
return llvm::ComputeEditDistance(
makeArrayRef(data(), size()),
makeArrayRef(Other.data(), Other.size()),
AllowReplacements, MaxEditDistance);
}
//===----------------------------------------------------------------------===//
// String Operations
//===----------------------------------------------------------------------===//
std::string StringRef::lower() const {
std::string Result(size(), char());
for (size_type i = 0, e = size(); i != e; ++i) {
Result[i] = toLower(Data[i]);
}
return Result;
}
std::string StringRef::upper() const {
std::string Result(size(), char());
for (size_type i = 0, e = size(); i != e; ++i) {
Result[i] = toUpper(Data[i]);
}
return Result;
}
//===----------------------------------------------------------------------===//
// String Searching
//===----------------------------------------------------------------------===//
/// 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 StringRef::find(StringRef Str, size_t From) const {
if (From > Length)
return npos;
const char *Start = Data + From;
size_t Size = Length - From;
const char *Needle = Str.data();
size_t N = Str.size();
if (N == 0)
return From;
if (Size < N)
return npos;
if (N == 1) {
const char *Ptr = (const char *)::memchr(Start, Needle[0], Size);
return Ptr == nullptr ? npos : Ptr - Data;
}
const char *Stop = Start + (Size - N + 1);
// For short haystacks or unsupported needles fall back to the naive algorithm
if (Size < 16 || N > 255) {
do {
if (std::memcmp(Start, Needle, N) == 0)
return Start - Data;
++Start;
} while (Start < Stop);
return npos;
}
// Build the bad char heuristic table, with uint8_t to reduce cache thrashing.
uint8_t BadCharSkip[256];
std::memset(BadCharSkip, N, 256);
for (unsigned i = 0; i != N-1; ++i)
BadCharSkip[(uint8_t)Str[i]] = N-1-i;
do {
uint8_t Last = Start[N - 1];
if (LLVM_UNLIKELY(Last == (uint8_t)Needle[N - 1]))
if (std::memcmp(Start, Needle, N - 1) == 0)
return Start - Data;
// Otherwise skip the appropriate number of bytes.
Start += BadCharSkip[Last];
} while (Start < Stop);
return npos;
}
size_t StringRef::find_lower(StringRef Str, size_t From) const {
StringRef This = substr(From);
while (This.size() >= Str.size()) {
if (This.startswith_lower(Str))
return From;
This = This.drop_front();
++From;
}
return npos;
}
size_t StringRef::rfind_lower(char C, size_t From) const {
From = std::min(From, Length);
size_t i = From;
while (i != 0) {
--i;
if (toLower(Data[i]) == toLower(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 StringRef::rfind(StringRef Str) const {
size_t N = Str.size();
if (N > Length)
return npos;
for (size_t i = Length - N + 1, e = 0; i != e;) {
--i;
if (substr(i, N).equals(Str))
return i;
}
return npos;
}
size_t StringRef::rfind_lower(StringRef Str) const {
size_t N = Str.size();
if (N > Length)
return npos;
for (size_t i = Length - N + 1, e = 0; i != e;) {
--i;
if (substr(i, N).equals_lower(Str))
return i;
}
return npos;
}
/// 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())
StringRef::size_type StringRef::find_first_of(StringRef Chars,
size_t From) const {
std::bitset<1 << CHAR_BIT> CharBits;
for (size_type i = 0; i != Chars.size(); ++i)
CharBits.set((unsigned char)Chars[i]);
for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
if (CharBits.test((unsigned char)Data[i]))
return i;
return npos;
}
/// find_first_not_of - Find the first character in the string that is not
/// \arg C or npos if not found.
StringRef::size_type StringRef::find_first_not_of(char C, size_t From) const {
for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
if (Data[i] != C)
return i;
return npos;
}
/// 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())
StringRef::size_type StringRef::find_first_not_of(StringRef Chars,
size_t From) const {
std::bitset<1 << CHAR_BIT> CharBits;
for (size_type i = 0; i != Chars.size(); ++i)
CharBits.set((unsigned char)Chars[i]);
for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
if (!CharBits.test((unsigned char)Data[i]))
return i;
return npos;
}
/// find_last_of - Find the last character in the string that is in \arg C,
/// or npos if not found.
///
/// Note: O(size() + Chars.size())
StringRef::size_type StringRef::find_last_of(StringRef Chars,
size_t From) const {
std::bitset<1 << CHAR_BIT> CharBits;
for (size_type i = 0; i != Chars.size(); ++i)
CharBits.set((unsigned char)Chars[i]);
for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
if (CharBits.test((unsigned char)Data[i]))
return i;
return npos;
}
/// find_last_not_of - Find the last character in the string that is not
/// \arg C, or npos if not found.
StringRef::size_type StringRef::find_last_not_of(char C, size_t From) const {
for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
if (Data[i] != C)
return i;
return npos;
}
/// find_last_not_of - Find the last character in the string that is not in
/// \arg Chars, or npos if not found.
///
/// Note: O(size() + Chars.size())
StringRef::size_type StringRef::find_last_not_of(StringRef Chars,
size_t From) const {
std::bitset<1 << CHAR_BIT> CharBits;
for (size_type i = 0, e = Chars.size(); i != e; ++i)
CharBits.set((unsigned char)Chars[i]);
for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
if (!CharBits.test((unsigned char)Data[i]))
return i;
return npos;
}
void StringRef::split(SmallVectorImpl<StringRef> &A,
StringRef Separator, int MaxSplit,
bool KeepEmpty) const {
StringRef S = *this;
// Count down from MaxSplit. When MaxSplit is -1, this will just split
// "forever". This doesn't support splitting more than 2^31 times
// intentionally; if we ever want that we can make MaxSplit a 64-bit integer
// but that seems unlikely to be useful.
while (MaxSplit-- != 0) {
size_t Idx = S.find(Separator);
if (Idx == npos)
break;
// Push this split.
if (KeepEmpty || Idx > 0)
A.push_back(S.slice(0, Idx));
// Jump forward.
S = S.slice(Idx + Separator.size(), npos);
}
// Push the tail.
if (KeepEmpty || !S.empty())
A.push_back(S);
}
void StringRef::split(SmallVectorImpl<StringRef> &A, char Separator,
int MaxSplit, bool KeepEmpty) const {
StringRef S = *this;
// Count down from MaxSplit. When MaxSplit is -1, this will just split
// "forever". This doesn't support splitting more than 2^31 times
// intentionally; if we ever want that we can make MaxSplit a 64-bit integer
// but that seems unlikely to be useful.
while (MaxSplit-- != 0) {
size_t Idx = S.find(Separator);
if (Idx == npos)
break;
// Push this split.
if (KeepEmpty || Idx > 0)
A.push_back(S.slice(0, Idx));
// Jump forward.
S = S.slice(Idx + 1, npos);
}
// Push the tail.
if (KeepEmpty || !S.empty())
A.push_back(S);
}
//===----------------------------------------------------------------------===//
// Helpful Algorithms
//===----------------------------------------------------------------------===//
/// count - Return the number of non-overlapped occurrences of \arg Str in
/// the string.
size_t StringRef::count(StringRef Str) const {
size_t Count = 0;
size_t N = Str.size();
if (!N || N > Length)
return 0;
for (size_t i = 0, e = Length - N + 1; i < e;) {
if (substr(i, N).equals(Str)) {
++Count;
i += N;
}
else
++i;
}
return Count;
}
static unsigned GetAutoSenseRadix(StringRef &Str) {
if (Str.empty())
return 10;
if (Str.startswith("0x") || Str.startswith("0X")) {
Str = Str.substr(2);
return 16;
}
if (Str.startswith("0b") || Str.startswith("0B")) {
Str = Str.substr(2);
return 2;
}
if (Str.startswith("0o")) {
Str = Str.substr(2);
return 8;
}
if (Str[0] == '0' && Str.size() > 1 && isDigit(Str[1])) {
Str = Str.substr(1);
return 8;
}
return 10;
}
bool llvm::consumeUnsignedInteger(StringRef &Str, unsigned Radix,
unsigned long long &Result) {
// Autosense radix if not specified.
if (Radix == 0)
Radix = GetAutoSenseRadix(Str);
// Empty strings (after the radix autosense) are invalid.
if (Str.empty()) return true;
// Parse all the bytes of the string given this radix. Watch for overflow.
StringRef Str2 = Str;
Result = 0;
while (!Str2.empty()) {
unsigned CharVal;
if (Str2[0] >= '0' && Str2[0] <= '9')
CharVal = Str2[0] - '0';
else if (Str2[0] >= 'a' && Str2[0] <= 'z')
CharVal = Str2[0] - 'a' + 10;
else if (Str2[0] >= 'A' && Str2[0] <= 'Z')
CharVal = Str2[0] - 'A' + 10;
else
break;
// If the parsed value is larger than the integer radix, we cannot
// consume any more characters.
if (CharVal >= Radix)
break;
// Add in this character.
unsigned long long PrevResult = Result;
Result = Result * Radix + CharVal;
// Check for overflow by shifting back and seeing if bits were lost.
if (Result / Radix < PrevResult)
return true;
Str2 = Str2.substr(1);
}
// We consider the operation a failure if no characters were consumed
// successfully.
if (Str.size() == Str2.size())
return true;
Str = Str2;
return false;
}
bool llvm::consumeSignedInteger(StringRef &Str, unsigned Radix,
long long &Result) {
unsigned long long ULLVal;
// Handle positive strings first.
if (Str.empty() || Str.front() != '-') {
if (consumeUnsignedInteger(Str, Radix, ULLVal) ||
// Check for value so large it overflows a signed value.
(long long)ULLVal < 0)
return true;
Result = ULLVal;
return false;
}
// Get the positive part of the value.
StringRef Str2 = Str.drop_front(1);
if (consumeUnsignedInteger(Str2, Radix, ULLVal) ||
// Reject values so large they'd overflow as negative signed, but allow
// "-0". This negates the unsigned so that the negative isn't undefined
// on signed overflow.
(long long)-ULLVal > 0)
return true;
Str = Str2;
Result = -ULLVal;
return false;
}
/// GetAsUnsignedInteger - Workhorse method that converts a integer character
/// sequence of radix up to 36 to an unsigned long long value.
bool llvm::getAsUnsignedInteger(StringRef Str, unsigned Radix,
unsigned long long &Result) {
if (consumeUnsignedInteger(Str, Radix, Result))
return true;
// For getAsUnsignedInteger, we require the whole string to be consumed or
// else we consider it a failure.
return !Str.empty();
}
bool llvm::getAsSignedInteger(StringRef Str, unsigned Radix,
long long &Result) {
if (consumeSignedInteger(Str, Radix, Result))
return true;
// For getAsSignedInteger, we require the whole string to be consumed or else
// we consider it a failure.
return !Str.empty();
}
bool StringRef::getAsInteger(unsigned Radix, APInt &Result) const {
StringRef Str = *this;
// Autosense radix if not specified.
if (Radix == 0)
Radix = GetAutoSenseRadix(Str);
assert(Radix > 1 && Radix <= 36);
// Empty strings (after the radix autosense) are invalid.
if (Str.empty()) return true;
// Skip leading zeroes. This can be a significant improvement if
// it means we don't need > 64 bits.
while (!Str.empty() && Str.front() == '0')
Str = Str.substr(1);
// If it was nothing but zeroes....
if (Str.empty()) {
Result = APInt(64, 0);
return false;
}
// (Over-)estimate the required number of bits.
unsigned Log2Radix = 0;
while ((1U << Log2Radix) < Radix) Log2Radix++;
bool IsPowerOf2Radix = ((1U << Log2Radix) == Radix);
unsigned BitWidth = Log2Radix * Str.size();
if (BitWidth < Result.getBitWidth())
BitWidth = Result.getBitWidth(); // don't shrink the result
else if (BitWidth > Result.getBitWidth())
Result = Result.zext(BitWidth);
APInt RadixAP, CharAP; // unused unless !IsPowerOf2Radix
if (!IsPowerOf2Radix) {
// These must have the same bit-width as Result.
RadixAP = APInt(BitWidth, Radix);
CharAP = APInt(BitWidth, 0);
}
// Parse all the bytes of the string given this radix.
Result = 0;
while (!Str.empty()) {
unsigned CharVal;
if (Str[0] >= '0' && Str[0] <= '9')
CharVal = Str[0]-'0';
else if (Str[0] >= 'a' && Str[0] <= 'z')
CharVal = Str[0]-'a'+10;
else if (Str[0] >= 'A' && Str[0] <= 'Z')
CharVal = Str[0]-'A'+10;
else
return true;
// If the parsed value is larger than the integer radix, the string is
// invalid.
if (CharVal >= Radix)
return true;
// Add in this character.
if (IsPowerOf2Radix) {
Result <<= Log2Radix;
Result |= CharVal;
} else {
Result *= RadixAP;
CharAP = CharVal;
Result += CharAP;
}
Str = Str.substr(1);
}
return false;
}
bool StringRef::getAsDouble(double &Result, bool AllowInexact) const {
APFloat F(0.0);
auto StatusOrErr = F.convertFromString(*this, APFloat::rmNearestTiesToEven);
if (errorToBool(StatusOrErr.takeError()))
return true;
APFloat::opStatus Status = *StatusOrErr;
if (Status != APFloat::opOK) {
if (!AllowInexact || !(Status & APFloat::opInexact))
return true;
}
Result = F.convertToDouble();
return false;
}
// Implementation of StringRef hashing.
hash_code llvm::hash_value(StringRef S) {
return hash_combine_range(S.begin(), S.end());
}