DirectXShaderCompiler/lib/Support/StringRef.cpp at main · microsoft/DirectXShaderCompiler · GitHub

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//===-- StringRef.cpp - Lightweight String References ---------------------===//

// The LLVM Compiler Infrastructure

// This file is distributed under the University of Illinois Open Source

// License. See LICENSE.TXT for details.

//===----------------------------------------------------------------------===//

#include "llvm/ADT/StringRef.h"

#include "llvm/ADT/APInt.h"

#include "llvm/ADT/Hashing.h"

#include "llvm/ADT/edit_distance.h"

#include <bitset>

#include <limits>

using namespace llvm;

// MSVC emits references to this into the translation units which reference it.

#ifndef _MSC_VER

const size_t StringRef::npos;

#endif

static char ascii_tolower(char x) {

if (x >= 'A' && x <= 'Z')

return x - 'A' + 'a';

return x;

}

static char ascii_toupper(char x) {

if (x >= 'a' && x <= 'z')

return x - 'a' + 'A';

return x;

}

static bool ascii_isdigit(char x) {

return x >= '0' && x <= '9';

}

// 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 = ascii_tolower(LHS[I]);

unsigned char RHC = ascii_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;

}

/// 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 (ascii_isdigit(Data[I]) && ascii_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 && ascii_isdigit(Data[J]);

bool rd = J < RHS.Length && ascii_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] = ascii_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] = ascii_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 {

size_t N = Str.size();

if (N > Length)

return npos;

// For short haystacks or unsupported needles fall back to the naive algorithm

if (Length < 16 || N > 255 || N == 0) {

for (size_t e = Length - N + 1, i = std::min(From, e); i != e; ++i)

if (substr(i, N).equals(Str))

return i;

return npos;

}

if (From >= Length)

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;

unsigned Len = Length-From, Pos = From;

while (Len >= N) {

if (substr(Pos, N).equals(Str)) // See if this is the correct substring.

return Pos;

// Otherwise skip the appropriate number of bytes.

uint8_t Skip = BadCharSkip[(uint8_t)(*this)[Pos+N-1]];

Len -= Skip;

Pos += Skip;

}

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;

}

/// 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 Separators, int MaxSplit,

bool KeepEmpty) const {

StringRef rest = *this;

// rest.data() is used to distinguish cases like "a," that splits into

// "a" + "" and "a" that splits into "a" + 0.

for (int splits = 0;

rest.data() != nullptr && (MaxSplit < 0 || splits < MaxSplit);

++splits) {

std::pair<StringRef, StringRef> p = rest.split(Separators);

if (KeepEmpty || p.first.size() != 0)

A.push_back(p.first);

rest = p.second;

}

// If we have a tail left, add it.

if (rest.data() != nullptr && (rest.size() != 0 || KeepEmpty))

A.push_back(rest);

}

//===----------------------------------------------------------------------===//

// 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 > Length)

return 0;

for (size_t i = 0, e = Length - N + 1; i != e; ++i)

if (substr(i, N).equals(Str))

++Count;

return Count;

}

static unsigned GetAutoSenseRadix(StringRef &Str) {

if (Str.startswith("0x")) {

Str = Str.substr(2);

return 16;

}

if (Str.startswith("0b")) {

Str = Str.substr(2);

return 2;

}

if (Str.startswith("0o")) {

Str = Str.substr(2);

return 8;

}

if (Str.startswith("0"))

return 8;

return 10;

}

/// 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) {

// 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.

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.

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;

Str = Str.substr(1);

}

return false;

}

bool llvm::getAsSignedInteger(StringRef Str, unsigned Radix,

long long &Result) {

unsigned long long ULLVal;

// Handle positive strings first.

if (Str.empty() || Str.front() != '-') {

if (getAsUnsignedInteger(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.

if (getAsUnsignedInteger(Str.substr(1), Radix, ULLVal) ||

// Reject values larger than what can be represented as negative signed.

// The most negative long long is LLONG_MIN, which has magnitude

// (LLONG_MAX + 1). Values larger than this magnitude cannot be negated

// without overflow.

ULLVal > static_cast<unsigned long long>(

std::numeric_limits<long long>::max()) +

return true;

Result = (~ULLVal + 1);

return false;

}

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;

}

// Implementation of StringRef hashing.

hash_code llvm::hash_value(StringRef S) {

return hash_combine_range(S.begin(), S.end());

}

DirectXShaderCompiler/lib/Support/StringRef.cpp at main · microsoft/DirectXShaderCompiler · GitHub

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