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/**
* @file llstringtable.h
* @brief The LLStringTable class provides a _fast_ method for finding
* unique copies of strings.
*
* Copyright (c) 2001-$CurrentYear$, Linden Research, Inc.
* $License$
*/
#ifndef LL_STRING_TABLE_H
#define LL_STRING_TABLE_H
#include "llstl.h"
#include <list>
#include <set>
#if LL_WINDOWS
# if (_MSC_VER >= 1300)
# define STRING_TABLE_HASH_MAP 1
# pragma warning(disable : 4996)
# endif
#else
//# define STRING_TABLE_HASH_MAP 1
#endif
#if STRING_TABLE_HASH_MAP
#include <hash_map>
#endif
// string_table.h
// LLStringTable class header file
// Provides a _fast_ method for finding unique copies of strings
//
// Copyright 2001-2002, Linden Research, Inc.
const U32 MAX_STRINGS_LENGTH = 256;
class LLStringTableEntry
{
public:
LLStringTableEntry(const char *str)
: mString(NULL), mCount(1)
{
// Copy string
U32 length = (U32)strlen(str) + 1; /*Flawfinder: ignore*/
length = llmin(length, MAX_STRINGS_LENGTH);
mString = new char[length];
strncpy(mString, str, length); /*Flawfinder: ignore*/
mString[length - 1] = 0;
}
~LLStringTableEntry()
{
delete [] mString;
mCount = 0;
}
void incCount() { mCount++; }
BOOL decCount() { return --mCount; }
char *mString;
S32 mCount;
};
class LLStringTable
{
public:
LLStringTable(int tablesize);
~LLStringTable();
char *checkString(const char *str);
char *checkString(const std::string& str);
LLStringTableEntry *checkStringEntry(const char *str);
LLStringTableEntry *checkStringEntry(const std::string& str);
char *addString(const char *str);
char *addString(const std::string& str);
LLStringTableEntry *addStringEntry(const char *str);
LLStringTableEntry *addStringEntry(const std::string& str);
void removeString(const char *str);
S32 mMaxEntries;
S32 mUniqueEntries;
#if STRING_TABLE_HASH_MAP
typedef std::hash_multimap<U32, LLStringTableEntry *> string_hash_t;
string_hash_t mStringHash;
#else
typedef std::list<LLStringTableEntry *> string_list_t;
typedef string_list_t * string_list_ptr_t;
string_list_ptr_t *mStringList;
#endif
};
extern LLStringTable gStringTable;
//============================================================================
// This class is designed to be used locally,
// e.g. as a member of an LLXmlTree
// Strings can be inserted only, then quickly looked up
typedef const std::string* LLStdStringHandle;
class LLStdStringTable
{
public:
LLStdStringTable(S32 tablesize = 0)
{
if (tablesize == 0)
{
tablesize = 256; // default
}
// Make sure tablesize is power of 2
for (S32 i = 31; i>0; i--)
{
if (tablesize & (1<<i))
{
if (tablesize >= (3<<(i-1)))
tablesize = (1<<(i+1));
else
tablesize = (1<<i);
break;
}
}
mTableSize = tablesize;
mStringList = new string_set_t[tablesize];
}
~LLStdStringTable()
{
cleanup();
delete[] mStringList;
}
void cleanup()
{
// remove strings
for (S32 i = 0; i<mTableSize; i++)
{
string_set_t& stringset = mStringList[i];
for (string_set_t::iterator iter = stringset.begin(); iter != stringset.end(); iter++)
{
delete *iter;
}
stringset.clear();
}
}
LLStdStringHandle lookup(const std::string& s)
{
U32 hashval = makehash(s);
return lookup(hashval, s);
}
LLStdStringHandle checkString(const std::string& s)
{
U32 hashval = makehash(s);
return lookup(hashval, s);
}
LLStdStringHandle insert(const std::string& s)
{
U32 hashval = makehash(s);
LLStdStringHandle result = lookup(hashval, s);
if (result == NULL)
{
result = new std::string(s);
mStringList[hashval].insert(result);
}
return result;
}
LLStdStringHandle addString(const std::string& s)
{
return insert(s);
}
private:
U32 makehash(const std::string& s)
{
S32 len = (S32)s.size();
const char* c = s.c_str();
U32 hashval = 0;
for (S32 i=0; i<len; i++)
{
hashval = ((hashval<<5) + hashval) + *c++;
}
return hashval & (mTableSize-1);
}
LLStdStringHandle lookup(U32 hashval, const std::string& s)
{
string_set_t& stringset = mStringList[hashval];
LLStdStringHandle handle = &s;
string_set_t::iterator iter = stringset.find(handle); // compares actual strings
if (iter != stringset.end())
{
return *iter;
}
else
{
return NULL;
}
}
private:
S32 mTableSize;
typedef std::set<LLStdStringHandle, compare_pointer_contents<std::string> > string_set_t;
string_set_t* mStringList; // [mTableSize]
};
#endif
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