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pkgcache.h: improved string hashing

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This commit is contained in:
Alexey Tourbin 2011-01-27 00:37:00 +03:00
parent 31e94207f5
commit 8fbf622172
1 changed files with 14 additions and 11 deletions
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25
apt/apt-pkg/pkgcache.h
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@ -110,7 +110,7 @@ class pkgCache
// CNC:2003-02-16 - Inlined here.
inline unsigned long sHash(const char *S) const;
inline unsigned long sHash(string S) const {return sHash(S.c_str());};
inline unsigned long sHash(const string &S) const {return sHash(S.c_str());};
public:
@ -131,8 +131,8 @@ class pkgCache
inline void *DataEnd() {return ((unsigned char *)Map.Data()) + Map.Size();};
// String hashing function (512 range)
inline unsigned long Hash(string S) const {return sHash(S);};
inline unsigned long Hash(const char *S) const {return sHash(S);};
inline unsigned long Hash(const char *S) const;
inline unsigned long Hash(const string &S) const {return Hash(S.c_str());};
// Usefull transformation things
const char *Priority(unsigned char Priority);
@ -312,15 +312,18 @@ struct pkgCache::StringItem
#include <apt-pkg/cacheiterators.h>
// CNC:2003-02-16 - Inlined here.
#include <ctype.h>
#define hash_count(a) (sizeof(a)/sizeof(a[0]))
inline unsigned long pkgCache::sHash(const char *Str) const
inline unsigned long pkgCache::sHash(const char *S) const
{
unsigned long Hash = 0;
for (const char *I = Str; *I != 0; I++)
//Hash = 5*Hash + tolower(*I);
Hash = 5*Hash + *I;
return Hash % hash_count(HeaderP->HashTable);
unsigned long h = 5381;
unsigned char c;
for (c = *S; c != '\0'; c = *++S)
h = h * 33 + c;
return h;
}
#define hash_count(a) (sizeof(a)/sizeof(a[0]))
inline unsigned long pkgCache::Hash(const char *S) const
{
return sHash(S) % hash_count(HeaderP->HashTable);
}
#undef hash_count