X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;ds=sidebyside;f=source%2Fcore%2Fhash.h;fp=source%2Fcore%2Fhash.h;h=1eebcce5342b75064034b7f68e5b2c82909b7fe2;hb=cf20196055ed5074c448a16144c47b7e8a32c6a8;hp=0000000000000000000000000000000000000000;hpb=928694ff233bd4383f30b05bf6d2d37562b77a9a;p=libs%2Fcore.git

diff --git a/source/core/hash.h b/source/core/hash.h
new file mode 100644
index 0000000..1eebcce
--- /dev/null
+++ b/source/core/hash.h
@@ -0,0 +1,41 @@
+#ifndef MSP_CORE_HASH_H_
+#define MSP_CORE_HASH_H_
+
+#include <string>
+
+namespace Msp {
+
+#ifdef WIN32
+typedef __uint64 HashValue64;
+#else
+typedef unsigned long long HashValue64;
+#endif
+
+/**
+Computes a 32-bit Fowler-Noll-Vo (FNV-1a) hash.  The number of bits can be
+limited to less than 32, in which case XOR-folding is used to reduce the hash
+size.
+*/
+unsigned hash32(const void *, unsigned, unsigned = 32);
+
+/**
+Convenience function to compute a 32-bit hash of a string.
+*/
+inline unsigned hash32(const std::string &s, unsigned b = 32)
+{ return hash32(s.data(), s.size(), b); }
+
+/**
+Computes a 64-bit Fowler-Noll-Vo (FNV-1a) hash.  Note that even if bits is
+limited to 32 or less, this does not produce the same result as hash32.
+*/
+HashValue64 hash64(const void *, unsigned, unsigned = 64);
+
+/**
+Convenience function to compute a 64-bit hash of a string.
+*/
+inline HashValue64 hash64(const std::string &s, unsigned b = 64)
+{ return hash64(s.data(), s.size(), b); }
+
+} // namespace Msp
+
+#endif