forked from OSchip/llvm-project
486 lines
14 KiB
C++
486 lines
14 KiB
C++
//===-- StringRef.cpp - Lightweight String References ---------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/StringRef.h"
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#include "llvm/ADT/APInt.h"
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#include "llvm/ADT/Hashing.h"
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#include "llvm/ADT/edit_distance.h"
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#include <bitset>
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using namespace llvm;
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// MSVC emits references to this into the translation units which reference it.
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#ifndef _MSC_VER
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const size_t StringRef::npos;
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#endif
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static char ascii_tolower(char x) {
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if (x >= 'A' && x <= 'Z')
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return x - 'A' + 'a';
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return x;
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}
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static char ascii_toupper(char x) {
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if (x >= 'a' && x <= 'z')
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return x - 'a' + 'A';
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return x;
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}
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static bool ascii_isdigit(char x) {
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return x >= '0' && x <= '9';
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}
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// strncasecmp() is not available on non-POSIX systems, so define an
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// alternative function here.
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static int ascii_strncasecmp(const char *LHS, const char *RHS, size_t Length) {
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for (size_t I = 0; I < Length; ++I) {
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unsigned char LHC = ascii_tolower(LHS[I]);
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unsigned char RHC = ascii_tolower(RHS[I]);
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if (LHC != RHC)
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return LHC < RHC ? -1 : 1;
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}
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return 0;
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}
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/// compare_lower - Compare strings, ignoring case.
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int StringRef::compare_lower(StringRef RHS) const {
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if (int Res = ascii_strncasecmp(Data, RHS.Data, std::min(Length, RHS.Length)))
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return Res;
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if (Length == RHS.Length)
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return 0;
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return Length < RHS.Length ? -1 : 1;
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}
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/// Check if this string starts with the given \p Prefix, ignoring case.
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bool StringRef::startswith_lower(StringRef Prefix) const {
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return Length >= Prefix.Length &&
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ascii_strncasecmp(Data, Prefix.Data, Prefix.Length) == 0;
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}
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/// Check if this string ends with the given \p Suffix, ignoring case.
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bool StringRef::endswith_lower(StringRef Suffix) const {
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return Length >= Suffix.Length &&
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ascii_strncasecmp(end() - Suffix.Length, Suffix.Data, Suffix.Length) == 0;
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}
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/// compare_numeric - Compare strings, handle embedded numbers.
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int StringRef::compare_numeric(StringRef RHS) const {
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for (size_t I = 0, E = std::min(Length, RHS.Length); I != E; ++I) {
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// Check for sequences of digits.
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if (ascii_isdigit(Data[I]) && ascii_isdigit(RHS.Data[I])) {
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// The longer sequence of numbers is considered larger.
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// This doesn't really handle prefixed zeros well.
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size_t J;
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for (J = I + 1; J != E + 1; ++J) {
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bool ld = J < Length && ascii_isdigit(Data[J]);
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bool rd = J < RHS.Length && ascii_isdigit(RHS.Data[J]);
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if (ld != rd)
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return rd ? -1 : 1;
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if (!rd)
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break;
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}
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// The two number sequences have the same length (J-I), just memcmp them.
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if (int Res = compareMemory(Data + I, RHS.Data + I, J - I))
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return Res < 0 ? -1 : 1;
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// Identical number sequences, continue search after the numbers.
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I = J - 1;
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continue;
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}
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if (Data[I] != RHS.Data[I])
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return (unsigned char)Data[I] < (unsigned char)RHS.Data[I] ? -1 : 1;
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}
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if (Length == RHS.Length)
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return 0;
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return Length < RHS.Length ? -1 : 1;
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}
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// Compute the edit distance between the two given strings.
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unsigned StringRef::edit_distance(llvm::StringRef Other,
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bool AllowReplacements,
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unsigned MaxEditDistance) const {
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return llvm::ComputeEditDistance(
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makeArrayRef(data(), size()),
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makeArrayRef(Other.data(), Other.size()),
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AllowReplacements, MaxEditDistance);
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}
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//===----------------------------------------------------------------------===//
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// String Operations
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//===----------------------------------------------------------------------===//
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std::string StringRef::lower() const {
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std::string Result(size(), char());
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for (size_type i = 0, e = size(); i != e; ++i) {
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Result[i] = ascii_tolower(Data[i]);
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}
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return Result;
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}
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std::string StringRef::upper() const {
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std::string Result(size(), char());
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for (size_type i = 0, e = size(); i != e; ++i) {
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Result[i] = ascii_toupper(Data[i]);
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}
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return Result;
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}
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//===----------------------------------------------------------------------===//
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// String Searching
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//===----------------------------------------------------------------------===//
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/// find - Search for the first string \arg Str in the string.
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///
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/// \return - The index of the first occurrence of \arg Str, or npos if not
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/// found.
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size_t StringRef::find(StringRef Str, size_t From) const {
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size_t N = Str.size();
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if (N > Length)
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return npos;
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// For short haystacks or unsupported needles fall back to the naive algorithm
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if (Length < 16 || N > 255 || N == 0) {
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for (size_t e = Length - N + 1, i = std::min(From, e); i != e; ++i)
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if (substr(i, N).equals(Str))
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return i;
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return npos;
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}
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if (From >= Length)
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return npos;
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// Build the bad char heuristic table, with uint8_t to reduce cache thrashing.
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uint8_t BadCharSkip[256];
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std::memset(BadCharSkip, N, 256);
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for (unsigned i = 0; i != N-1; ++i)
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BadCharSkip[(uint8_t)Str[i]] = N-1-i;
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unsigned Len = Length-From, Pos = From;
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while (Len >= N) {
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if (substr(Pos, N).equals(Str)) // See if this is the correct substring.
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return Pos;
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// Otherwise skip the appropriate number of bytes.
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uint8_t Skip = BadCharSkip[(uint8_t)(*this)[Pos+N-1]];
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Len -= Skip;
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Pos += Skip;
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}
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return npos;
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}
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/// rfind - Search for the last string \arg Str in the string.
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///
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/// \return - The index of the last occurrence of \arg Str, or npos if not
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/// found.
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size_t StringRef::rfind(StringRef Str) const {
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size_t N = Str.size();
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if (N > Length)
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return npos;
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for (size_t i = Length - N + 1, e = 0; i != e;) {
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--i;
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if (substr(i, N).equals(Str))
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return i;
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}
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return npos;
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}
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/// find_first_of - Find the first character in the string that is in \arg
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/// Chars, or npos if not found.
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///
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/// Note: O(size() + Chars.size())
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StringRef::size_type StringRef::find_first_of(StringRef Chars,
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size_t From) const {
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std::bitset<1 << CHAR_BIT> CharBits;
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for (size_type i = 0; i != Chars.size(); ++i)
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CharBits.set((unsigned char)Chars[i]);
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for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
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if (CharBits.test((unsigned char)Data[i]))
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return i;
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return npos;
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}
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/// find_first_not_of - Find the first character in the string that is not
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/// \arg C or npos if not found.
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StringRef::size_type StringRef::find_first_not_of(char C, size_t From) const {
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for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
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if (Data[i] != C)
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return i;
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return npos;
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}
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/// find_first_not_of - Find the first character in the string that is not
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/// in the string \arg Chars, or npos if not found.
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///
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/// Note: O(size() + Chars.size())
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StringRef::size_type StringRef::find_first_not_of(StringRef Chars,
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size_t From) const {
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std::bitset<1 << CHAR_BIT> CharBits;
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for (size_type i = 0; i != Chars.size(); ++i)
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CharBits.set((unsigned char)Chars[i]);
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for (size_type i = std::min(From, Length), e = Length; i != e; ++i)
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if (!CharBits.test((unsigned char)Data[i]))
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return i;
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return npos;
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}
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/// find_last_of - Find the last character in the string that is in \arg C,
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/// or npos if not found.
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///
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/// Note: O(size() + Chars.size())
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StringRef::size_type StringRef::find_last_of(StringRef Chars,
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size_t From) const {
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std::bitset<1 << CHAR_BIT> CharBits;
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for (size_type i = 0; i != Chars.size(); ++i)
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CharBits.set((unsigned char)Chars[i]);
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for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
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if (CharBits.test((unsigned char)Data[i]))
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return i;
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return npos;
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}
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/// find_last_not_of - Find the last character in the string that is not
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/// \arg C, or npos if not found.
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StringRef::size_type StringRef::find_last_not_of(char C, size_t From) const {
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for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
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if (Data[i] != C)
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return i;
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return npos;
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}
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/// find_last_not_of - Find the last character in the string that is not in
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/// \arg Chars, or npos if not found.
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///
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/// Note: O(size() + Chars.size())
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StringRef::size_type StringRef::find_last_not_of(StringRef Chars,
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size_t From) const {
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std::bitset<1 << CHAR_BIT> CharBits;
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for (size_type i = 0, e = Chars.size(); i != e; ++i)
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CharBits.set((unsigned char)Chars[i]);
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for (size_type i = std::min(From, Length) - 1, e = -1; i != e; --i)
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if (!CharBits.test((unsigned char)Data[i]))
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return i;
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return npos;
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}
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void StringRef::split(SmallVectorImpl<StringRef> &A,
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StringRef Separators, int MaxSplit,
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bool KeepEmpty) const {
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StringRef rest = *this;
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// rest.data() is used to distinguish cases like "a," that splits into
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// "a" + "" and "a" that splits into "a" + 0.
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for (int splits = 0;
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rest.data() != nullptr && (MaxSplit < 0 || splits < MaxSplit);
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++splits) {
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std::pair<StringRef, StringRef> p = rest.split(Separators);
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if (KeepEmpty || p.first.size() != 0)
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A.push_back(p.first);
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rest = p.second;
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}
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// If we have a tail left, add it.
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if (rest.data() != nullptr && (rest.size() != 0 || KeepEmpty))
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A.push_back(rest);
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}
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//===----------------------------------------------------------------------===//
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// Helpful Algorithms
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//===----------------------------------------------------------------------===//
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/// count - Return the number of non-overlapped occurrences of \arg Str in
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/// the string.
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size_t StringRef::count(StringRef Str) const {
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size_t Count = 0;
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size_t N = Str.size();
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if (N > Length)
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return 0;
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for (size_t i = 0, e = Length - N + 1; i != e; ++i)
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if (substr(i, N).equals(Str))
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++Count;
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return Count;
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}
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static unsigned GetAutoSenseRadix(StringRef &Str) {
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if (Str.startswith("0x")) {
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Str = Str.substr(2);
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return 16;
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}
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if (Str.startswith("0b")) {
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Str = Str.substr(2);
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return 2;
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}
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if (Str.startswith("0o")) {
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Str = Str.substr(2);
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return 8;
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}
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if (Str.startswith("0"))
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return 8;
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return 10;
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}
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/// GetAsUnsignedInteger - Workhorse method that converts a integer character
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/// sequence of radix up to 36 to an unsigned long long value.
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bool llvm::getAsUnsignedInteger(StringRef Str, unsigned Radix,
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unsigned long long &Result) {
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// Autosense radix if not specified.
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if (Radix == 0)
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Radix = GetAutoSenseRadix(Str);
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// Empty strings (after the radix autosense) are invalid.
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if (Str.empty()) return true;
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// Parse all the bytes of the string given this radix. Watch for overflow.
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Result = 0;
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while (!Str.empty()) {
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unsigned CharVal;
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if (Str[0] >= '0' && Str[0] <= '9')
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CharVal = Str[0]-'0';
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else if (Str[0] >= 'a' && Str[0] <= 'z')
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CharVal = Str[0]-'a'+10;
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else if (Str[0] >= 'A' && Str[0] <= 'Z')
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CharVal = Str[0]-'A'+10;
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else
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return true;
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// If the parsed value is larger than the integer radix, the string is
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// invalid.
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if (CharVal >= Radix)
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return true;
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// Add in this character.
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unsigned long long PrevResult = Result;
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Result = Result*Radix+CharVal;
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// Check for overflow by shifting back and seeing if bits were lost.
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if (Result/Radix < PrevResult)
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return true;
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Str = Str.substr(1);
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}
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return false;
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}
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bool llvm::getAsSignedInteger(StringRef Str, unsigned Radix,
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long long &Result) {
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unsigned long long ULLVal;
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// Handle positive strings first.
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if (Str.empty() || Str.front() != '-') {
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if (getAsUnsignedInteger(Str, Radix, ULLVal) ||
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// Check for value so large it overflows a signed value.
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(long long)ULLVal < 0)
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return true;
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Result = ULLVal;
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return false;
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}
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// Get the positive part of the value.
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if (getAsUnsignedInteger(Str.substr(1), Radix, ULLVal) ||
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// Reject values so large they'd overflow as negative signed, but allow
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// "-0". This negates the unsigned so that the negative isn't undefined
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// on signed overflow.
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(long long)-ULLVal > 0)
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return true;
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Result = -ULLVal;
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return false;
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}
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bool StringRef::getAsInteger(unsigned Radix, APInt &Result) const {
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StringRef Str = *this;
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// Autosense radix if not specified.
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if (Radix == 0)
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Radix = GetAutoSenseRadix(Str);
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assert(Radix > 1 && Radix <= 36);
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// Empty strings (after the radix autosense) are invalid.
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if (Str.empty()) return true;
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// Skip leading zeroes. This can be a significant improvement if
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// it means we don't need > 64 bits.
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while (!Str.empty() && Str.front() == '0')
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Str = Str.substr(1);
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// If it was nothing but zeroes....
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if (Str.empty()) {
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Result = APInt(64, 0);
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return false;
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}
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// (Over-)estimate the required number of bits.
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unsigned Log2Radix = 0;
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while ((1U << Log2Radix) < Radix) Log2Radix++;
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bool IsPowerOf2Radix = ((1U << Log2Radix) == Radix);
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unsigned BitWidth = Log2Radix * Str.size();
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if (BitWidth < Result.getBitWidth())
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BitWidth = Result.getBitWidth(); // don't shrink the result
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else if (BitWidth > Result.getBitWidth())
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Result = Result.zext(BitWidth);
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APInt RadixAP, CharAP; // unused unless !IsPowerOf2Radix
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if (!IsPowerOf2Radix) {
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// These must have the same bit-width as Result.
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RadixAP = APInt(BitWidth, Radix);
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CharAP = APInt(BitWidth, 0);
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}
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// Parse all the bytes of the string given this radix.
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Result = 0;
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while (!Str.empty()) {
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unsigned CharVal;
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if (Str[0] >= '0' && Str[0] <= '9')
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CharVal = Str[0]-'0';
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else if (Str[0] >= 'a' && Str[0] <= 'z')
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CharVal = Str[0]-'a'+10;
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else if (Str[0] >= 'A' && Str[0] <= 'Z')
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CharVal = Str[0]-'A'+10;
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else
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return true;
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// If the parsed value is larger than the integer radix, the string is
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// invalid.
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if (CharVal >= Radix)
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return true;
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// Add in this character.
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if (IsPowerOf2Radix) {
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Result <<= Log2Radix;
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Result |= CharVal;
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} else {
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Result *= RadixAP;
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CharAP = CharVal;
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Result += CharAP;
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}
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Str = Str.substr(1);
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}
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return false;
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}
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// Implementation of StringRef hashing.
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hash_code llvm::hash_value(StringRef S) {
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return hash_combine_range(S.begin(), S.end());
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}
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