/**

  * vim: set ts=4 :

  * =============================================================================

  * SourceMod

  * Copyright (C) 2004-2007 AlliedModders LLC.  All rights reserved.

  * =============================================================================

  *

  * This program is free software; you can redistribute it and/or modify it under

  * the terms of the GNU General Public License, version 3.0, as published by the

  * Free Software Foundation.

  * 

  * This program is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more

  * details.

  *

  * You should have received a copy of the GNU General Public License along with

  * this program.  If not, see <http://www.gnu.org/licenses/>.

  *

  * As a special exception, AlliedModders LLC gives you permission to link the

  * code of this program (as well as its derivative works) to "Half-Life 2," the

  * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

  * by the Valve Corporation.  You must obey the GNU General Public License in

  * all respects for all other code used.  Additionally, AlliedModders LLC grants

  * this exception to all derivative works.  AlliedModders LLC defines further

  * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

  * or <http://www.sourcemod.net/license.php>.

  *

  * Version: $Id$

  */

 #ifndef _INCLUDE_SOURCEMOD_TEMPLATED_TRIE_H_

 #define _INCLUDE_SOURCEMOD_TEMPLATED_TRIE_H_

 #include <new>

 #include <string.h>

 #include <malloc.h>

 #include <assert.h>

 enum NodeType

 {

 	Node_Unused = 0,		/* Node is not being used (sparse) */

 	Node_Arc,				/* Node is part of an arc and does not terminate */

 	Node_Term,				/* Node is a terminator */

 };

 /**

  * @brief Trie class for storing key/value pairs, based on double array tries.

  * @file sm_trie_tpl.h

  *

  * For full works cited and implementation overview, there is a big comment 

  * block at the bottom of this file.

  */

 template <typename K>

 class KTrie

 {

 	class KTrieNode;

 public:

 	/**

 	 * @brief Clears all set objects in the trie.

 	 */

 	void clear()

 	{

 		run_destructors();

 		internal_clear();

 	}

 	/**

 	 * @brief Removes a key from the trie.

 	 *

 	 * @param key		Key to remove.

 	 * @return			True on success, false if key was never set.

 	 */

 	bool remove(const char *key)

 	{

 		KTrieNode *node = internal_retrieve(key);

 		if (!node || !node->valset)

 		{

 			return false;

 		}

 		node->value.~K();

 		node->valset = false;

 		return true;

 	}

 	/**

 	 * @brief Retrieves a pointer to the object stored at a given key.

 	 *

 	 * @param key		Key to retrieve.

 	 * @return			Pointer to object, or NULL if key was not found or not set.

 	 */

 	K * retrieve(const char *key)

 	{

 		KTrieNode *node = internal_retrieve(key);

 		if (!node || !node->valset)

 		{

 			return NULL;

 		}

 		return &node->value;

 	}

 	/**

 	 * @brief Inserts or updates the object stored at a key.

 	 *

 	 * @param key		Key to update or insert.

 	 * @param obj		Object to store at the key.

 	 * @return			True on success, false on failure.

 	 */

 	bool replace(const char *key, const K & obj)

 	{

 		KTrieNode *prev_node = internal_retrieve(key);

 		if (!prev_node)

 		{

 			return insert(key, obj);

 		}

 		if (prev_node->valset)

 		{

 			prev_node->value.~K();

 		}

 		new (&prev_node->value) K(obj);

 		return true;

 	}

 	/**

 	 * @brief Inserts an object at a key.

 	 *

 	 * @param key		Key to insert at.

 	 * @param obj		Object to store at the key.

 	 * @return			True on success, false if the key is already set or 

 	 *					insertion otherwise failed.

 	 */

 	bool insert(const char *key, const K & obj)

 	{

 		unsigned int lastidx = 1;		/* the last node index */

 		unsigned int curidx;			/* current node index */

 		const char *keyptr = key;		/* input stream at current token */

 		KTrieNode *node = NULL;			/* current node being processed */

 		KTrieNode *basenode = NULL;		/* current base node being processed */

 		unsigned int q;					/* temporary var for x_check results */

 		unsigned int curoffs;			/* current offset */

 		/* Do not handle empty strings for simplicity */

 		if (!*key)

 		{

 			return false;

 		}

 		/* Start traversing at the root node (1) */

 		do

 		{

 			/* Find where the next character is, then advance */

 			curidx = m_base[lastidx].idx;

 			basenode = &m_base[curidx];

 			curoffs = charval(*keyptr);

 			curidx += curoffs;

 			node = &m_base[curidx];

 			keyptr++;

 			/* Check if this slot is supposed to be empty.  If so, we need to handle CASES 1/2:

 			 * Insertion without collisions

 			 */

 			if ( (curidx > m_baseSize) || (node->mode == Node_Unused) )

 			{

 				if (curidx > m_baseSize)

 				{

 					if (!grow())

 					{

 						return false;

 					}

 					node = &m_base[curidx];

 				}

 				node->parent = lastidx;

 				if (*keyptr == '\0')

 				{

 					node->mode = Node_Arc;

 				}

 				else

 				{

 					node->idx = x_addstring(keyptr);

 					node->mode = Node_Term;

 				}

 				node->valset = true;

 				new (&node->value) K(obj);

 				return true;

 			}

 			else if (node->parent != lastidx)

 			{

 				/* Collision! We have to split up the tree here.  CASE 4:

 				 * Insertion when a new word is inserted with a collision.

 				 * NOTE: This is the hardest case to handle.  All below examples are based on:

 				 * BACHELOR, BADGE, inserting BABY.

 				 * The problematic production here is A -> B, where B is already being used.

 			     *

 				 * This process has to rotate one half of the 'A' arc.  We generate two lists:

 				 *  Outgoing Arcs - Anything leaving this 'A'

 				 *  Incoming Arcs - Anything going to this 'A'

 				 * Whichever list is smaller will be moved.  Note that this works because the intersection

 				 * affects both arc chains, and moving one will make the slot available to either.

 				 */

 				KTrieNode *cur;

 				/* Find every node arcing from the last node.

 				 * I.e. for BACHELOR, BADGE, BABY,

 				 * The arcs leaving A will be C and D, but our current node is B -> *.

 				 * Thus, we use the last index (A) to find the base for arcs leaving A.

 				 */

 				unsigned int outgoing_base = m_base[lastidx].idx;

 				unsigned int outgoing_list[256];

 				unsigned int outgoing_count = 0;	/* count the current index here */

 				cur = &m_base[outgoing_base] + 1;

 				unsigned int outgoing_limit = 255;

 				if (outgoing_base + outgoing_limit > m_baseSize)

 				{

 					outgoing_limit = m_baseSize - outgoing_base;

 				}

 				for (unsigned int i=1; i<=outgoing_limit; i++,cur++)

 				{

 					if (cur->mode == Node_Unused || cur->parent != lastidx)

 					{

 						continue;

 					}

 					outgoing_list[outgoing_count++] = i;

 				}

 				outgoing_list[outgoing_count++] = curidx - outgoing_base;

 				/* Now we need to find all the arcs leaving our parent...

 				 * Note: the inconsistency is the base of our parent.  

 				 */

 				assert(m_base[node->parent].mode == Node_Arc);

 				unsigned int incoming_list[256];

 				unsigned int incoming_base = m_base[node->parent].idx;

 				unsigned int incoming_count = 0;

 				unsigned int incoming_limit = 255;

 				cur = &m_base[incoming_base] + 1;

 				if (incoming_base + incoming_limit > m_baseSize)

 				{

 					incoming_limit = m_baseSize - incoming_base;

 				}

 				assert(incoming_limit > 0 && incoming_limit <= 255);

 				for (unsigned int i=1; i<=incoming_limit; i++,cur++)

 				{

 					if (cur->mode == Node_Arc || cur->mode == Node_Term)

 					{

 						if (cur->parent == node->parent)

 						{

 							incoming_list[incoming_count++] = i;

 						}

 					}

 				}

 				if (incoming_count < outgoing_count + 1)

 				{

 					unsigned int q = x_check_multi(incoming_list, incoming_count);

 					node = &m_base[curidx];

 					/* If we're incoming, we need to modify our parent */

 					m_base[node->parent].idx = q;

 					/* For each node in the "to move" list,

 					 * Relocate the node's info to the new position.

 					 */

 					unsigned int idx, newidx, oldidx;

 					for (unsigned int i=0; i<incoming_count; i++)

 					{

 						idx = incoming_list[i];

 						newidx = q + idx;

 						oldidx = incoming_base + idx;

 						if (oldidx == lastidx)

 						{

 							/* Important! Make sure we're not invalidating our sacred lastidx */

 							lastidx = newidx;

 						}

 						/* Fully copy the node */

 						memcpy(&m_base[newidx], &m_base[oldidx], sizeof(KTrieNode));

 						if (m_base[oldidx].valset)

 						{

 							new (&m_base[newidx].value) K(m_base[oldidx].value);

 							m_base[oldidx].value.~K();

 						}

 						assert(m_base[m_base[newidx].parent].mode == Node_Arc);

 						/* Erase old data */

 						memset(&m_base[oldidx], 0, sizeof(KTrieNode));

 						/* If we are not a terminator, we have children we must take care of */

 						if (m_base[newidx].mode == Node_Arc)

 						{

 							KTrieNode *check_base = &m_base[m_base[newidx].idx] + 1;

 							outgoing_limit = (m_base + m_baseSize + 1) - check_base;

 							if (outgoing_limit > 255)

 							{

 								outgoing_limit = 255;

 							}

 							for (unsigned int j=1; j<=outgoing_limit; j++, check_base++)

 							{

 								if (check_base->parent == oldidx)

 								{

 									check_base->parent = newidx;

 								}

 							}

 						}

 					}

 				}

 				else

 				{

 					unsigned int q = x_check_multi(outgoing_list, outgoing_count);

 					node = &m_base[curidx];

 					/* If we're outgoing, we need to modify our own base */

 					m_base[lastidx].idx = q;

 					/* Take the last index (curidx) out of the list.  Technically we are not moving this,

 					 * since it's already being used by something else.  

 					 */

 					outgoing_count--;

 					/* For each node in the "to move" list,

 					 * Relocate the node's info to the new position.

 					 */

 					unsigned int idx, newidx, oldidx;

 					for (unsigned int i=0; i<outgoing_count; i++)

 					{

 						idx = outgoing_list[i];

 						newidx = q + idx;

 						oldidx = outgoing_base + idx;

 						if (oldidx == lastidx)

 						{

 							/* Important! Make sure we're not invalidating our sacred lastidx */

 							lastidx = newidx;

 						}

 						/* Fully copy the node */

 						memcpy(&m_base[newidx], &m_base[oldidx], sizeof(KTrieNode));

 						if (m_base[oldidx].valset)

 						{

 							new (&m_base[newidx].value) K(m_base[oldidx].value);

 							m_base[oldidx].value.~K();

 						}

 						assert(m_base[m_base[newidx].parent].mode == Node_Arc);

 						/* Erase old data */

 						memset(&m_base[oldidx], 0, sizeof(KTrieNode));

 						/* If we are not a terminator, we have children we must take care of */

 						if (m_base[newidx].mode == Node_Arc)

 						{

 							KTrieNode *check_base = &m_base[m_base[newidx].idx] + 1;

 							outgoing_limit = (m_base + m_baseSize + 1) - check_base;

 							if (outgoing_limit > 255)

 							{

 								outgoing_limit = 255;

 							}

 							for (unsigned int j=1; j<=outgoing_limit; j++, check_base++)

 							{

 								if (check_base->parent == oldidx)

 								{

 									check_base->parent = newidx;

 								}

 							}

 						}

 					}

 					/* Take the invisible node and use it as our new node */

 					node = &m_base[q + outgoing_list[outgoing_count]];

 				}

 				/* We're finally done! */

 				node->parent = lastidx;

 				if (*keyptr == '\0')

 				{

 					node->mode = Node_Arc;

 				}

 				else

 				{

 					node->idx = x_addstring(keyptr);

 					node->mode = Node_Term;

 				}

 				node->valset = true;

 				new (&node->value) K(obj);

 				return true;

 			}

 			else

 			{

 				/* See what's in the next node - special case if terminator! */

 				if (node->mode == Node_Term)

 				{

 					/* If we're a terminator, we need to handle CASE 3:

 					 * Insertion when a terminating collision occurs

 					 */

 					char *term = &m_stringtab[node->idx];

 					/* Do an initial browsing to make sure they're not the same string */

 					if (strcmp(keyptr, term) == 0)

 					{

 						if (!node->valset)

 						{

 							node->valset = true;

 							new (&node->value) K(obj);

 							return true;

 						}

 						/* Same string.  We can't insert. */

 						return false;

 					}

 					/* For each matching character pair, we need to disband the terminator.

 					 * This splits the similar prefix into a single arc path.

 					 * First, save the old values so we can move them to a new node.

 					 * Next, for each loop:

 					 *  Take the current (invalid) node, and point it to the next arc base.

 					 *  Set the current node to the node at the next arc.

 					 */

 					K oldvalue;

 					bool oldvalset = node->valset;

 					if (oldvalset)

 					{

 						oldvalue = node->value;

 					}

 					if (*term == *keyptr)

 					{

 						while (*term == *keyptr)

 						{

 							/* Find the next free slot in the check array.

 							 * This is the "vector base" essentially

 							 */

 							q = x_check(*term);

 							node = &m_base[curidx];

 							/* Point the node to the next new base */

 							node->idx = q;

 							node->mode = Node_Arc;

 							if (node->valset == true)

 							{

 								node->value.~K();

 								node->valset = false;

 							}

 							/* Advance the input stream and local variables */

 							lastidx = curidx;

 							curidx = q + charval(*term);

 							node = &m_base[curidx];

 							/* Make sure the new current node has its parent set. */

 							node->parent = lastidx;

 							node->mode = Node_Arc;	/* Just in case we run x_check again */

 							*term = '\0';	/* Unmark the string table here */

 							term++;

 							keyptr++;

 						}

 					}

 					else if (node->valset)

 					{

 						node->valset = false;

 						node->value.~K();

 					}

 					/* We're done inserting new pairs.  If one of them is exhausted,

 					 * we take special shortcuts.

 					 */

 					if (*term == '\0')				//EX: BADGERHOUSE added over B -> ADGER.  

 					{

 						/* First backpatch the current node - it ends the newly split terminator.

 						 * In the example, this would mean the node is the production from R -> ?

 						 * This node ends the old BADGER, so we set it here.

 						 */

 						node->valset = oldvalset;

 						if (node->valset)

 						{

 							new (&node->value) K(oldvalue);

 						}

 						/* The terminator was split up, but pieces of keyptr remain.

 						 * We need to generate a new production, in this example, R -> H,

 						 * with H being a terminator to OUSE.  Thus we get:

 						 * B,A,D,G,E,R*,H*->OUSE (* = value set).

 						 * NOTE: parent was last set at the end of the while loop.

 						 */

 						/* Get the new base and apply re-basing */

 						q = x_check(*keyptr);

 						node = &m_base[curidx];

 						node->idx = q;

 						node->mode = Node_Arc;

 						lastidx = curidx;

 						/* Finish the final node */

 						curidx = q + charval(*keyptr);

 						node = &m_base[curidx];

 						keyptr++;

 						/* Optimize - don't add to string table if there's nothing more to eat */

 						if (*keyptr == '\0')

 						{

 							node->mode = Node_Arc;

 						}

 						else

 						{

 							node->idx = x_addstring(keyptr);

 							node->mode = Node_Term;

 						}

 						node->parent = lastidx;

 						node->valset = true;

 						new (&node->value) K(obj);

 					}

 					else if (*keyptr == '\0')

 					{	//EX: BADGER added over B -> ADGERHOUSE

 						/* First backpatch the current node - it ends newly split input string.

 						 * This is the exact opposite of the above procedure.

 						 */

 						node->valset = true;

 						new (&node->value) K(obj);

 						/* Get the new base and apply re-basing */

 						q = x_check(*term);

 						node = &m_base[curidx];

 						node->idx = q;

 						node->mode = Node_Arc;

 						lastidx = curidx;

 						/* Finish the final node */

 						curidx = q + charval(*term);

 						node = &m_base[curidx];

 						term++;

 						/* Optimize - don't add to string table if there's nothing more to eat */

 						if (*term == '\0')

 						{

 							node->mode = Node_Arc;

 						}

 						else

 						{

 							node->idx = (term - m_stringtab); /* Already in the string table! */

 							node->mode = Node_Term;

 						}

 						node->parent = lastidx;

 						node->valset = oldvalset;

 						if (node->valset)

 						{

 							new (&node->value) K(oldvalue);

 						}

 					}

 					else

 					{

 						/* Finally, we have to create two new nodes instead of just one. */

 						node->mode = Node_Arc;

 						/* Get the new base and apply re-basing */

 						q = x_check2(*keyptr, *term);

 						node = &m_base[curidx];

 						node->idx = q;

 						lastidx = curidx;

 						/* Re-create the old terminated node */

 						curidx = q + charval(*term);

 						node = &m_base[curidx];

 						term++;

 						node->valset = oldvalset;

 						if (node->valset)

 						{

 							new (&node->value) K(oldvalue);

 						}

 						node->parent = lastidx;

 						if (*term == '\0')

 						{

 							node->mode = Node_Arc;

 						}

 						else

 						{

 							node->mode = Node_Term;

 							node->idx = (term - m_stringtab); /* Already in the string table! */

 						}

 						/* Create the new keyed input node */

 						curidx = q + charval(*keyptr);

 						node = &m_base[curidx];

 						keyptr++;

 						node->valset = true;

 						new (&node->value) K(obj);

 						node->parent = lastidx;

 						if (*keyptr == '\0')

 						{

 							node->mode = Node_Arc;

 						}

 						else

 						{

 							node->mode = Node_Term;

 							node->idx = x_addstring(keyptr);

 						}

 					}

 					/* Phew! */

 					return true;

 				}

 				else

 				{

 					assert(node->mode == Node_Arc);

 				}

 			}

 			lastidx = curidx;

 		} while (*keyptr != '\0');

 		assert(node);

 		/* If we've exhausted the string and we have a valid reached node,

 		 * the production rule already existed.  Make sure it's valid to set first.

 		 */

 		/* We have to be an Arc.  If the last result was anything else, we would have returned a new 

 		 * production earlier.

 		 */

 		assert(node->mode == Node_Arc);

 		if (!node->valset)

 		{

 			node->valset = true;

 			new (&node->value) K(obj);

 			return true;

 		}

 		return false;

 	}

 public:

 	KTrie()

 	{

 		m_base = (KTrieNode *)malloc(sizeof(KTrieNode) * (256 + 1));

 		m_stringtab = (char *)malloc(sizeof(char) * 256);

 		m_baseSize = 256;

 		m_stSize = 256;

 		internal_clear();

 	}

 	~KTrie()

 	{

 		run_destructors();

 		free(m_base);

 		free(m_stringtab);

 	}

 private:

 	class KTrieNode

 	{

 		friend class KTrie;

 	private:

 		/**

 		 * For Node_Arc, this index stores the 'base' offset to the next arc chain.

 		 *   I.e. to jump from this arc to character C, it will be at base[idx+C].

 		 * For Node_Term, this is an index into the string table.

 		 */

 		unsigned int idx;	

 		/**

 		 * This contains the prior arc that we must have come from.

 		 * For example, if arc 63 has a base jump of index 12, and we want to see if

 		 * there is a valid character C, the parent of 12+C must be 63.

 		 */

 		unsigned int parent;

 		K value;				/* Value associated with this node */

 		NodeType mode;			/* Current usage type of the node */

 		bool valset;			/* Whether or not a value is set */

 	};

 private:

 	KTrieNode *internal_retrieve(const char *key)

 	{

 		unsigned int lastidx = 1;		/* the last node index */

 		unsigned int curidx;			/* current node index */

 		const char *keyptr = key;		/* input stream at current token */

 		KTrieNode *node = NULL;			/* current node being processed */

 		if (!*key)

 		{

 			return NULL;

 		}

 		/* Start traversing at the root node */

 		do

 		{

 			/* Find where the next character is, then advance */

 			curidx = m_base[lastidx].idx;

 			node = &m_base[curidx];

 			curidx += charval(*keyptr);

 			node = &m_base[curidx];

 			keyptr++;

 			/* Check if this slot is supposed to be empty or is a collision */

 			if ((curidx > m_baseSize) || node->mode == Node_Unused || node->parent != lastidx)

 			{

 				return NULL;

 			}

 			else if (node->mode == Node_Term)

 			{

 				char *term = &m_stringtab[node->idx];

 				if (strcmp(keyptr, term) == 0)

 				{

 					break;

 				}

 				else

 				{

 					return NULL;

 				}

 			}

 			lastidx = curidx;

 		} while (*keyptr != '\0');

 		return node;

 	}

 	bool grow()

 	{

 		/* The current # of nodes in the tree is trie->baseSize + 1 */

 		unsigned int cur_size = m_baseSize;

 		unsigned int new_size = cur_size * 2;

 		KTrieNode *new_base = (KTrieNode *)malloc((new_size + 1) * sizeof(KTrieNode));

 		if (!new_base)

 		{

 			return false;

 		}

 		memcpy(new_base, m_base, sizeof(KTrieNode) * (m_baseSize + 1));

 		memset(&new_base[cur_size + 1], 0, (new_size - cur_size) * sizeof(KTrieNode));

 		for (size_t i = 0; i <= m_baseSize; i++)

 		{

 			if (m_base[i].valset)

 			{

 				/* Placement construct+copy the object, then placement destroy the old. */

 				new (&new_base[i].value) K(m_base[i].value);

 				m_base[i].value.~K();

 			}

 		}

 		free(m_base);

 		m_base = new_base;

 		m_baseSize = new_size;

 		return true;

 	}

 	inline unsigned char charval(char c)

 	{

 		return (unsigned char)c;

 	}

 	void internal_clear()

 	{

 		m_tail = 0;

 		memset(m_base, 0, sizeof(KTrieNode) * (m_baseSize + 1));

 		memset(m_stringtab, 0, sizeof(char) * m_stSize);

 		/* Sentinel root node */

 		m_base[1].idx = 1;

 		m_base[1].mode = Node_Arc;

 		m_base[1].parent = 1;

 	}

 	void run_destructors()

 	{

 		for (size_t i = 0; i <= m_baseSize; i++)

 		{

 			if (m_base[i].valset)

 			{

 				m_base[i].value.~K();

 			}

 		}

 	}

 	unsigned int x_addstring(const char *ptr)

 	{

 		size_t len = strlen(ptr) + 1;

 		if (m_tail + len >= m_stSize)

 		{		

 			while (m_tail + len >= m_stSize)

 			{

 				m_stSize *= 2;

 			}

 			m_stringtab = (char *)realloc(m_stringtab,m_stSize);

 		}

 		unsigned int tail = m_tail;

 		strcpy(&m_stringtab[tail], ptr);

 		m_tail += len;

 		return tail;

 	}

 	unsigned int x_check(char c, unsigned int start=1)

 	{

 		unsigned char _c = charval(c);

 		unsigned int to_check = m_baseSize - _c;

 		for (unsigned int i=start; i<=to_check; i++)

 		{

 			if (m_base[i+_c].mode == Node_Unused)

 			{

 				return i;

 			}

 		}

 		grow();

 		return x_check(c, to_check+1);

 	}

 	unsigned int x_check2(char c1, char c2, unsigned int start=1)

 	{

 		unsigned char _c1 = charval(c1);

 		unsigned char _c2 = charval(c2);

 		unsigned int to_check = m_baseSize - (_c1 > _c2 ? _c1 : _c2);

 		for (unsigned int i=start; i<=to_check; i++)

 		{

 			if (m_base[i+_c1].mode == Node_Unused

 				&& m_base[i+_c2].mode == Node_Unused)

 			{

 				return i;

 			}

 		}

 		grow();

 		return x_check2(c1, c2, to_check+1);

 	}

 	unsigned int x_check_multi(

 		unsigned int offsets[], 

 		unsigned int count,

 		unsigned int start=1)

 	{

 		KTrieNode *cur;

 		unsigned int to_check = m_baseSize;

 		unsigned int highest = 0;

 		for (unsigned int i=0; i<count; i++)

 		{

 			if (offsets[i] > highest)

 			{

 				highest = offsets[i];

 			}

 		}

 		to_check -= highest;

 		for (unsigned int i=start; i<=to_check; i++)

 		{

 			bool okay = true;

 			for (unsigned int j=0; j<count; j++)

 			{

 				cur = &m_base[i+offsets[j]];

 				if (cur->mode != Node_Unused)

 				{

 					okay = false;

 					break;

 				}

 			}

 			if (okay)

 			{

 				return i;

 			}

 		}

 		grow();

 		return x_check_multi(offsets, count, to_check+1);

 	}

 private:

 	KTrieNode *m_base;			/* Base array for the sparse tables */

 	char *m_stringtab;			/* String table pointer */

 	unsigned int m_baseSize;	/* Size of the base array, in members */

 	unsigned int m_stSize;		/* Size of the string table, in bytes */

 	unsigned int m_tail;		/* Current unused offset into the string table */

 };

 /**

  * Double Array Trie algorithm, based on:

  * An Efficient Implementation of Trie Structures, by

  *  Jun-ichi Aoe and Katsushi Maromoto, and Takashi Sato

  * from Software - Practice and Experience, Vol. 22(9), 695-721 (September 1992)

  *

  *  A Trie is a simple data structure which stores strings as DFAs, with each 

  * transition state being a string entry.  For example, observe the following strings:

  *

  * BAILOPAN, BAT, BACON, BACK

  *  These transition as the follow production rules:

  *  B -> ...                  B

  *       A -> ...             BA

  *            I -> ...        BAI

  *                 LOPAN      BAILOPAN

  *            T -> ...        BAT

  *            C ->            BAC

  *                 O -> ...   BACO

  *                      N     BACON

  *                 K          BACK

  *

  *  The standard implementation for this - using lists - gives a slow linear lookup, somewhere between

  * O(N+M) or O(log n).  A faster implementation is proposed in the paper above, which is based on compacting

  * the transition states into two arrays.  In the paper's implementation, two arrays are used, and thus it is

  * called the "Double Array" algorithm.  However, the CHECK array's size is maintained the same as BASE, 

  * so they can be combined into one structure.  The array seems complex at first, but is very simple: it is a

  * tree structure flattened out into a single vector.  I am calling this implementation the Flat Array Trie.

  *

  *  BASE[] is an array where each member is a node in the Trie.  The node can either be UNUSED (empty), an ARC

  * (containing an offset to the next set of ARCs), or a TERMINATOR (contains the rest of a string).

  * Each node has an index which must be interpreted based on the node type.  If the node is a TERMINATOR, then the

  * index is an index into a string table, to find the rest of the string.  

  *  If the node is an ARC, the index is another index into BASE.  For each possible token that can follow the

  * current token, the value of those tokens can be added to the index given in the ARC.  Thus, given a current

  * position and the next desired token, the current arc will jump to another arc which can contain either:

  *   1) An invalid production (collision, no entry exists)

  *   2) An empty production (no entry exists)

  *   3) Another arc label (the string ends here or continues into more productions)

  *   4) A TERMINATOR (the string ends here and contains an unused set of productions)

  * 

  *  So, given current offset N (starting at N=1), jumping to token C means the next offset will be:

  *      offs = BASE[n] + C

  *  Thus, the next node will be at:

  *      BASE[BASE[n] + C]

  * 

  *  This allows each ARC to specify the base offset for any of its ARC children, like a tree.  Each node specifies

  * its parent ARC -- so if an invalid offset is specified, the parent will not match, and thus no such derived 

  * string exists.

  *

  *  This means that arrays can be laid out "sparsely," maximizing their usage.  Note that N need not be related to

  * the range of tokens (1-256).  I.e., a base index does not have to be at 1, 256, 512, et cetera.  This is because

  * insertion comes with a small deal of complexity.  To insert a new set of tokens T, the algorithm finds a new 

  * BASE index N such that BASE[N+T[i]] is unused for each T[i].  Thus, indirection is not necessarily linear; 

  * traversing a chain of ARC nodes can _and will_ jump around BASE.

  *

  *  Of course, given this level of flexibility in the array organization, there are collisions.  This is largely 

  * where insertions become slow, as the old chain must be relocated before the new one is used.  Relocation means 

  * finding one or more new base indexes, and this means traversing BASE until an acceptable index is found, such 

  * that each offset is unused (see description in previous paragraph).

  *

  *  However, it is not insertion time we are concerned about.  The "trie" name comes from reTRIEval.  We are only

  * concerned with lookup and deletion.  Both lookup and deletion are O(k), where k is relative to the length of the 

  * input string.  Note that it is best case O(1) and worst case O(k).  Deleting the entire trie is always O(1).

  */

 #endif //_INCLUDE_SOURCEMOD_TEMPLATED_TRIE_H_