X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FStringRef.cpp;h=e73c6e38e2f41146209b290d88326fce25a22d9e;hb=11c2defa9157bd589cb322218c718c4492ed5746;hp=2d023e4895d068b915cdfaaa70e3da929b64b2cc;hpb=58ce7acb4f87c3caf0f473f89220950919fba7bc;p=oota-llvm.git diff --git a/lib/Support/StringRef.cpp b/lib/Support/StringRef.cpp index 2d023e4895d..e73c6e38e2f 100644 --- a/lib/Support/StringRef.cpp +++ b/lib/Support/StringRef.cpp @@ -8,6 +8,10 @@ //===----------------------------------------------------------------------===// #include "llvm/ADT/StringRef.h" +#include "llvm/ADT/APInt.h" +#include "llvm/ADT/OwningPtr.h" +#include + using namespace llvm; // MSVC emits references to this into the translation units which reference it. @@ -21,20 +25,138 @@ static char ascii_tolower(char x) { 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'; +} + /// compare_lower - Compare strings, ignoring case. int StringRef::compare_lower(StringRef RHS) const { for (size_t I = 0, E = min(Length, RHS.Length); I != E; ++I) { - char LHC = ascii_tolower(Data[I]); - char RHC = ascii_tolower(RHS.Data[I]); + unsigned char LHC = ascii_tolower(Data[I]); + unsigned char RHC = ascii_tolower(RHS.Data[I]); if (LHC != RHC) return LHC < RHC ? -1 : 1; } if (Length == RHS.Length) - return 0; + return 0; + return Length < RHS.Length ? -1 : 1; +} + +/// compare_numeric - Compare strings, handle embedded numbers. +int StringRef::compare_numeric(StringRef RHS) const { + for (size_t I = 0, E = 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) { + // The algorithm implemented below is the "classic" + // dynamic-programming algorithm for computing the Levenshtein + // distance, which is described here: + // + // http://en.wikipedia.org/wiki/Levenshtein_distance + // + // Although the algorithm is typically described using an m x n + // array, only two rows are used at a time, so this implemenation + // just keeps two separate vectors for those two rows. + size_type m = size(); + size_type n = Other.size(); + + const unsigned SmallBufferSize = 64; + unsigned SmallBuffer[SmallBufferSize]; + llvm::OwningArrayPtr Allocated; + unsigned *previous = SmallBuffer; + if (2*(n + 1) > SmallBufferSize) { + previous = new unsigned [2*(n+1)]; + Allocated.reset(previous); + } + unsigned *current = previous + (n + 1); + + for (unsigned i = 0; i <= n; ++i) + previous[i] = i; + + for (size_type y = 1; y <= m; ++y) { + current[0] = y; + unsigned BestThisRow = current[0]; + + for (size_type x = 1; x <= n; ++x) { + if (AllowReplacements) { + current[x] = min(previous[x-1] + ((*this)[y-1] == Other[x-1]? 0u:1u), + min(current[x-1], previous[x])+1); + } + else { + if ((*this)[y-1] == Other[x-1]) current[x] = previous[x-1]; + else current[x] = min(current[x-1], previous[x]) + 1; + } + BestThisRow = min(BestThisRow, current[x]); + } + + if (MaxEditDistance && BestThisRow > MaxEditDistance) + return MaxEditDistance + 1; + + unsigned *tmp = current; + current = previous; + previous = tmp; + } + + unsigned Result = previous[n]; + return Result; +} + +//===----------------------------------------------------------------------===// +// 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 //===----------------------------------------------------------------------===// @@ -42,21 +164,47 @@ int StringRef::compare_lower(StringRef RHS) const { /// find - Search for the first string \arg Str in the string. /// -/// \return - The index of the first occurence of \arg Str, or npos if not +/// \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 (size_t e = Length - N + 1, i = min(From, e); i != e; ++i) - if (substr(i, N).equals(Str)) - return i; + + // 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 = 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 occurence of \arg Str, or npos if not +/// \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(); @@ -73,11 +221,15 @@ size_t StringRef::rfind(StringRef Str) const { /// 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()) +/// 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 = min(From, Length), e = Length; i != e; ++i) - if (Chars.find(Data[i]) != npos) + if (CharBits.test((unsigned char)Data[i])) return i; return npos; } @@ -94,15 +246,34 @@ StringRef::size_type StringRef::find_first_not_of(char C, size_t From) 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()) +/// 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 = min(From, Length), e = Length; i != e; ++i) - if (Chars.find(Data[i]) == npos) + 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 = min(From, Length) - 1, e = -1; i != e; --i) + if (CharBits.test((unsigned char)Data[i])) + return i; + return npos; +} //===----------------------------------------------------------------------===// // Helpful Algorithms @@ -121,27 +292,32 @@ size_t StringRef::count(StringRef Str) const { return Count; } +static unsigned GetAutoSenseRadix(StringRef &Str) { + if (Str.startswith("0x")) { + Str = Str.substr(2); + return 16; + } else if (Str.startswith("0b")) { + Str = Str.substr(2); + return 2; + } else if (Str.startswith("0")) { + return 8; + } else { + return 10; + } +} + + /// GetAsUnsignedInteger - Workhorse method that converts a integer character /// sequence of radix up to 36 to an unsigned long long value. static bool GetAsUnsignedInteger(StringRef Str, unsigned Radix, unsigned long long &Result) { // Autosense radix if not specified. - if (Radix == 0) { - if (Str.startswith("0x")) { - Str = Str.substr(2); - Radix = 16; - } else if (Str.startswith("0b")) { - Str = Str.substr(2); - Radix = 2; - } else if (Str.startswith("0")) - Radix = 8; - else - Radix = 10; - } - + 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()) { @@ -154,23 +330,23 @@ static bool GetAsUnsignedInteger(StringRef Str, unsigned Radix, 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. if (Result < PrevResult) return true; Str = Str.substr(1); } - + return false; } @@ -181,7 +357,7 @@ bool StringRef::getAsInteger(unsigned Radix, unsigned long long &Result) const { bool StringRef::getAsInteger(unsigned Radix, long long &Result) const { unsigned long long ULLVal; - + // Handle positive strings first. if (empty() || front() != '-') { if (GetAsUnsignedInteger(*this, Radix, ULLVal) || @@ -191,7 +367,7 @@ bool StringRef::getAsInteger(unsigned Radix, long long &Result) const { Result = ULLVal; return false; } - + // Get the positive part of the value. if (GetAsUnsignedInteger(substr(1), Radix, ULLVal) || // Reject values so large they'd overflow as negative signed, but allow @@ -199,7 +375,7 @@ bool StringRef::getAsInteger(unsigned Radix, long long &Result) const { // on signed overflow. (long long)-ULLVal > 0) return true; - + Result = -ULLVal; return false; } @@ -220,4 +396,79 @@ bool StringRef::getAsInteger(unsigned Radix, unsigned &Result) const { return true; Result = Val; 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 + 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; +}