Imported existing code

indra/llcommon/llstringtable.cpp

@@ -0,0 +1,347 @@
+/** 
+ * @file llstringtable.cpp
+ * @brief The LLStringTable class provides a _fast_ method for finding
+ * unique copies of strings.
+ *
+ * $LicenseInfo:firstyear=2001&license=viewergpl$
+ * 
+ * Copyright (c) 2001-2009, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at
+ * http://secondlifegrid.net/programs/open_source/licensing/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ * $/LicenseInfo$
+ */
+
+#include "linden_common.h"
+
+#include "llstringtable.h"
+#include "llstl.h"
+
+LLStringTable gStringTable(32768);
+
+LLStringTable::LLStringTable(int tablesize)
+: mUniqueEntries(0)
+{
+	S32 i;
+	if (!tablesize)
+		tablesize = 4096; // some arbitrary default
+	// Make sure tablesize is power of 2
+	for (i = 31; i>0; i--)
+	{
+		if (tablesize & (1<<i))
+		{
+			if (tablesize >= (3<<(i-1)))
+				tablesize = (1<<(i+1));
+			else
+				tablesize = (1<<i);
+			break;
+		}
+	}
+	mMaxEntries = tablesize;
+
+#if !STRING_TABLE_HASH_MAP
+	// ALlocate strings
+	mStringList = new string_list_ptr_t[mMaxEntries];
+	// Clear strings
+	for (i = 0; i < mMaxEntries; i++)
+	{
+		mStringList[i] = NULL;
+	}
+#endif
+}
+
+LLStringTable::~LLStringTable()
+{
+#if !STRING_TABLE_HASH_MAP
+	if (mStringList)
+	{
+		for (S32 i = 0; i < mMaxEntries; i++)
+		{
+			if (mStringList[i])
+			{
+				string_list_t::iterator iter;
+				for (iter = mStringList[i]->begin(); iter != mStringList[i]->end(); iter++)
+					delete *iter; // *iter = (LLStringTableEntry*)
+			}
+			delete mStringList[i];
+		}
+		delete [] mStringList;
+		mStringList = NULL;
+	}
+#else
+	// Need to clean up the string hash
+	for_each(mStringHash.begin(), mStringHash.end(), DeletePairedPointer());
+	mStringHash.clear();
+#endif
+}
+
+
+static U32 hash_my_string(const char *str, int max_entries)
+{
+	U32 retval = 0;
+#if 0
+	while (*str)
+	{
+		retval <<= 1;
+		retval += *str++;
+	}
+#else
+	while (*str)
+	{
+		retval = (retval<<4) + *str;
+		U32 x = (retval & 0xf0000000);
+		if (x) retval = retval ^ (x>>24);
+		retval = retval & (~x);
+		str++;
+	}
+#endif
+	return (retval & (max_entries-1)); // max_entries is gauranteed to be power of 2
+}
+
+char* LLStringTable::checkString(const std::string& str)
+{
+	return checkString(str.c_str());
+}
+
+char* LLStringTable::checkString(const char *str)
+{
+    LLStringTableEntry* entry = checkStringEntry(str);
+    if (entry)
+    {
+	return entry->mString;
+    }
+    else
+    {
+	return NULL;
+    }
+}
+
+LLStringTableEntry* LLStringTable::checkStringEntry(const std::string& str)
+{
+    return checkStringEntry(str.c_str());
+}
+
+LLStringTableEntry* LLStringTable::checkStringEntry(const char *str)
+{
+	if (str)
+	{
+		char *ret_val;
+		LLStringTableEntry	*entry;
+		U32					hash_value = hash_my_string(str, mMaxEntries);
+#if STRING_TABLE_HASH_MAP
+#if 1 // Microsoft
+		string_hash_t::iterator lower = mStringHash.lower_bound(hash_value);
+		string_hash_t::iterator upper = mStringHash.upper_bound(hash_value);
+#else // stlport
+		std::pair<string_hash_t::iterator, string_hash_t::iterator> P = mStringHash.equal_range(hash_value);
+		string_hash_t::iterator lower = P.first;
+		string_hash_t::iterator upper = P.second;
+#endif
+		for (string_hash_t::iterator iter = lower; iter != upper; iter++)
+		{
+			entry = iter->second;
+			ret_val = entry->mString;
+			if (!strncmp(ret_val, str, MAX_STRINGS_LENGTH))
+			{
+				return entry;
+			}
+		}
+#else
+		string_list_t		*strlist = mStringList[hash_value];
+		if (strlist)
+		{
+			string_list_t::iterator iter;
+			for (iter = strlist->begin(); iter != strlist->end(); iter++)
+			{
+				entry = *iter;
+				ret_val = entry->mString;
+				if (!strncmp(ret_val, str, MAX_STRINGS_LENGTH))
+				{
+					return entry;
+				}
+			}
+		}
+#endif
+	}
+	return NULL;
+}
+
+char* LLStringTable::addString(const std::string& str)
+{
+	//RN: safe to use temporary c_str since string is copied
+	return addString(str.c_str());
+}
+
+char* LLStringTable::addString(const char *str)
+{
+
+    LLStringTableEntry* entry = addStringEntry(str);
+    if (entry)
+    {
+	return entry->mString;
+    }
+    else
+    {
+	return NULL;
+    }
+}
+
+LLStringTableEntry* LLStringTable::addStringEntry(const std::string& str)
+{
+    return addStringEntry(str.c_str());
+}
+
+LLStringTableEntry* LLStringTable::addStringEntry(const char *str)
+{
+	if (str)
+	{
+		char *ret_val = NULL;
+		LLStringTableEntry	*entry;
+		U32					hash_value = hash_my_string(str, mMaxEntries);
+#if STRING_TABLE_HASH_MAP
+#if 1 // Microsoft
+		string_hash_t::iterator lower = mStringHash.lower_bound(hash_value);
+		string_hash_t::iterator upper = mStringHash.upper_bound(hash_value);
+#else // stlport
+		std::pair<string_hash_t::iterator, string_hash_t::iterator> P = mStringHash.equal_range(hash_value);
+		string_hash_t::iterator lower = P.first;
+		string_hash_t::iterator upper = P.second;
+#endif
+		for (string_hash_t::iterator iter = lower; iter != upper; iter++)
+		{
+			entry = iter->second;
+			ret_val = entry->mString;
+			if (!strncmp(ret_val, str, MAX_STRINGS_LENGTH))
+			{
+				entry->incCount();
+				return entry;
+			}
+		}
+
+		// not found, so add!
+		LLStringTableEntry* newentry = new LLStringTableEntry(str);
+		ret_val = newentry->mString;
+		mStringHash.insert(string_hash_t::value_type(hash_value, newentry));
+#else
+		string_list_t		*strlist = mStringList[hash_value];
+
+		if (strlist)
+		{
+			string_list_t::iterator iter;
+			for (iter = strlist->begin(); iter != strlist->end(); iter++)
+			{
+				entry = *iter;
+				ret_val = entry->mString;
+				if (!strncmp(ret_val, str, MAX_STRINGS_LENGTH))
+				{
+					entry->incCount();
+					return entry;
+				}
+			}
+		}
+		else
+		{
+			mStringList[hash_value] = new string_list_t;
+			strlist = mStringList[hash_value];
+		}
+
+		// not found, so add!
+		LLStringTableEntry *newentry = new LLStringTableEntry(str);
+		//ret_val = newentry->mString;
+		strlist->push_front(newentry);
+#endif
+		mUniqueEntries++;
+		return newentry;
+	}
+	else
+	{
+		return NULL;
+	}
+}
+
+void LLStringTable::removeString(const char *str)
+{
+	if (str)
+	{
+		char *ret_val;
+		LLStringTableEntry	*entry;
+		U32					hash_value = hash_my_string(str, mMaxEntries);
+#if STRING_TABLE_HASH_MAP
+		{
+#if 1 // Microsoft
+			string_hash_t::iterator lower = mStringHash.lower_bound(hash_value);
+			string_hash_t::iterator upper = mStringHash.upper_bound(hash_value);
+#else // stlport
+			std::pair<string_hash_t::iterator, string_hash_t::iterator> P = mStringHash.equal_range(hash_value);
+			string_hash_t::iterator lower = P.first;
+			string_hash_t::iterator upper = P.second;
+#endif
+			for (string_hash_t::iterator iter = lower; iter != upper; iter++)
+			{
+				entry = iter->second;
+				ret_val = entry->mString;
+				if (!strncmp(ret_val, str, MAX_STRINGS_LENGTH))
+				{
+					if (!entry->decCount())
+					{
+						mUniqueEntries--;
+						if (mUniqueEntries < 0)
+						{
+							llerror("LLStringTable:removeString trying to remove too many strings!", 0);
+						}
+						delete iter->second;
+						mStringHash.erase(iter);
+					}
+					return;
+				}
+			}
+		}
+#else
+		string_list_t		*strlist = mStringList[hash_value];
+
+		if (strlist)
+		{
+			string_list_t::iterator iter;
+			for (iter = strlist->begin(); iter != strlist->end(); iter++)
+			{
+				entry = *iter;
+				ret_val = entry->mString;
+				if (!strncmp(ret_val, str, MAX_STRINGS_LENGTH))
+				{
+					if (!entry->decCount())
+					{
+						mUniqueEntries--;
+						if (mUniqueEntries < 0)
+						{
+							llerror("LLStringTable:removeString trying to remove too many strings!", 0);
+						}
+						strlist->remove(entry);
+						delete entry;
+					}
+					return;
+				}
+			}
+		}
+#endif
+	}
+}
+