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-rw-r--r--lib/Support/StringRef.cpp168
1 files changed, 90 insertions, 78 deletions
diff --git a/lib/Support/StringRef.cpp b/lib/Support/StringRef.cpp
index b5b4f94..abe570f 100644
--- a/lib/Support/StringRef.cpp
+++ b/lib/Support/StringRef.cpp
@@ -10,6 +10,8 @@
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/Hashing.h"
+#include "llvm/ADT/edit_distance.h"
#include <bitset>
using namespace llvm;
@@ -25,6 +27,12 @@ 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';
}
@@ -78,56 +86,29 @@ int StringRef::compare_numeric(StringRef RHS) const {
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<unsigned> 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]);
- }
+ return llvm::ComputeEditDistance(
+ llvm::ArrayRef<char>(data(), size()),
+ llvm::ArrayRef<char>(Other.data(), Other.size()),
+ AllowReplacements, MaxEditDistance);
+}
- if (MaxEditDistance && BestThisRow > MaxEditDistance)
- return MaxEditDistance + 1;
+//===----------------------------------------------------------------------===//
+// String Operations
+//===----------------------------------------------------------------------===//
- unsigned *tmp = current;
- current = previous;
- previous = tmp;
+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;
+}
- unsigned Result = previous[n];
+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;
}
@@ -144,9 +125,35 @@ 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;
}
@@ -223,6 +230,27 @@ StringRef::size_type StringRef::find_last_of(StringRef Chars,
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() != NULL && (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() != NULL && (rest.size() != 0 || KeepEmpty))
+ A.push_back(rest);
+}
+
//===----------------------------------------------------------------------===//
// Helpful Algorithms
//===----------------------------------------------------------------------===//
@@ -257,8 +285,8 @@ static unsigned GetAutoSenseRadix(StringRef &Str) {
/// 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) {
+bool llvm::getAsUnsignedInteger(StringRef Str, unsigned Radix,
+ unsigned long long &Result) {
// Autosense radix if not specified.
if (Radix == 0)
Radix = GetAutoSenseRadix(Str);
@@ -298,17 +326,13 @@ static bool GetAsUnsignedInteger(StringRef Str, unsigned Radix,
return false;
}
-bool StringRef::getAsInteger(unsigned Radix, unsigned long long &Result) const {
- return GetAsUnsignedInteger(*this, Radix, Result);
-}
-
-
-bool StringRef::getAsInteger(unsigned Radix, long long &Result) const {
+bool llvm::getAsSignedInteger(StringRef Str, unsigned Radix,
+ long long &Result) {
unsigned long long ULLVal;
// Handle positive strings first.
- if (empty() || front() != '-') {
- if (GetAsUnsignedInteger(*this, Radix, ULLVal) ||
+ 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;
@@ -317,7 +341,7 @@ bool StringRef::getAsInteger(unsigned Radix, long long &Result) const {
}
// Get the positive part of the value.
- if (GetAsUnsignedInteger(substr(1), Radix, ULLVal) ||
+ if (getAsUnsignedInteger(Str.substr(1), 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.
@@ -328,24 +352,6 @@ bool StringRef::getAsInteger(unsigned Radix, long long &Result) const {
return false;
}
-bool StringRef::getAsInteger(unsigned Radix, int &Result) const {
- long long Val;
- if (getAsInteger(Radix, Val) ||
- (int)Val != Val)
- return true;
- Result = Val;
- return false;
-}
-
-bool StringRef::getAsInteger(unsigned Radix, unsigned &Result) const {
- unsigned long long Val;
- if (getAsInteger(Radix, Val) ||
- (unsigned)Val != Val)
- return true;
- Result = Val;
- return false;
-}
-
bool StringRef::getAsInteger(unsigned Radix, APInt &Result) const {
StringRef Str = *this;
@@ -420,3 +426,9 @@ bool StringRef::getAsInteger(unsigned Radix, APInt &Result) const {
return false;
}
+
+
+// Implementation of StringRef hashing.
+hash_code llvm::hash_value(StringRef S) {
+ return hash_combine_range(S.begin(), S.end());
+}
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