Add generic support for hashing StringRef objects using the new hashing library.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152003 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2012-03-04 10:55:27 +00:00
parent e3e394d982
commit 528f0bbe19
3 changed files with 30 additions and 0 deletions

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@ -19,6 +19,7 @@ namespace llvm {
template<typename T>
class SmallVectorImpl;
class APInt;
class hash_code;
/// StringRef - Represent a constant reference to a string, i.e. a character
/// array and a length, which need not be null terminated.
@ -490,6 +491,9 @@ namespace llvm {
/// @}
/// \brief Compute a hash_code for a StringRef.
hash_code hash_value(StringRef S);
// StringRefs can be treated like a POD type.
template <typename T> struct isPodLike;
template <> struct isPodLike<StringRef> { static const bool value = true; };

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@ -10,6 +10,7 @@
#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>
@ -447,3 +448,9 @@ 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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@ -9,6 +9,7 @@
#include "gtest/gtest.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
@ -291,4 +292,22 @@ TEST(StringRefTest, Misc) {
EXPECT_EQ("hello", OS.str());
}
TEST(StringRefTest, Hashing) {
EXPECT_EQ(hash_value(std::string()), hash_value(StringRef()));
EXPECT_EQ(hash_value(std::string()), hash_value(StringRef("")));
std::string S = "hello world";
hash_code H = hash_value(S);
EXPECT_EQ(H, hash_value(StringRef("hello world")));
EXPECT_EQ(H, hash_value(StringRef(S)));
EXPECT_NE(H, hash_value(StringRef("hello worl")));
EXPECT_EQ(hash_value(std::string("hello worl")),
hash_value(StringRef("hello worl")));
EXPECT_NE(H, hash_value(StringRef("hello world ")));
EXPECT_EQ(hash_value(std::string("hello world ")),
hash_value(StringRef("hello world ")));
EXPECT_EQ(H, hash_value(StringRef("hello world\0")));
EXPECT_NE(hash_value(std::string("ello worl")),
hash_value(StringRef("hello world").slice(1, -1)));
}
} // end anonymous namespace