postgres/contrib/tsearch2/ts_lexize.c

/*
 * lexize stream of lexemes 
 * Teodor Sigaev <teodor@sigaev.ru>
 */
#include "postgres.h"

#include <ctype.h>
#include <locale.h>

#include "ts_cfg.h"
#include "dict.h"

void
LexizeInit(LexizeData *ld, TSCfgInfo *cfg) {
	ld->cfg = cfg;
	ld->curDictId = InvalidOid;
	ld->posDict = 0;
	ld->towork.head = ld->towork.tail = ld->curSub = NULL;
	ld->waste.head = ld->waste.tail = NULL;
	ld->lastRes=NULL;
	ld->tmpRes=NULL;
}

static void
LPLAddTail(ListParsedLex *list, ParsedLex *newpl) {
	if ( list->tail ) {
		list->tail->next = newpl;
		list->tail = newpl;
	} else
		list->head = list->tail = newpl;
	newpl->next = NULL;
}

static ParsedLex*
LPLRemoveHead(ListParsedLex *list) {
	ParsedLex *res = list->head;

	if ( list->head ) 
		list->head = list->head->next;

	if ( list->head == NULL )
		list->tail = NULL;

	return res;
}


void
LexizeAddLemm(LexizeData *ld, int type, char *lemm, int lenlemm) {
	ParsedLex *newpl = (ParsedLex*)palloc( sizeof(ParsedLex) );

	newpl = (ParsedLex*)palloc( sizeof(ParsedLex) );
	newpl->type = type;
	newpl->lemm = lemm;
	newpl->lenlemm = lenlemm;
	LPLAddTail(&ld->towork, newpl);
	ld->curSub = ld->towork.tail;
}

static void
RemoveHead(LexizeData *ld) {
	LPLAddTail(&ld->waste, LPLRemoveHead(&ld->towork));

	ld->posDict = 0;
}

static void
setCorrLex(LexizeData *ld, ParsedLex **correspondLexem) {
	if ( correspondLexem ) {
		*correspondLexem = ld->waste.head;
	} else {
		ParsedLex	*tmp, *ptr = ld->waste.head;

		while(ptr) {
			tmp = ptr->next;
			pfree(ptr);
			ptr = tmp;
		}
	}
	ld->waste.head = ld->waste.tail = NULL;
}

static void
moveToWaste(LexizeData *ld, ParsedLex *stop) {
	bool	go = true;

	while( ld->towork.head && go) {
		if (ld->towork.head == stop) {
			ld->curSub = stop->next;
			go = false;
		}
		RemoveHead(ld);
	}
}

static void
setNewTmpRes(LexizeData *ld, ParsedLex *lex, TSLexeme *res) {
	if ( ld->tmpRes ) {
		TSLexeme	*ptr;
		for( ptr=ld->tmpRes; ptr->lexeme; ptr++ ) 
			pfree( ptr->lexeme );
		pfree( ld->tmpRes );
	}
	ld->tmpRes = res;
	ld->lastRes = lex;
}

TSLexeme*
LexizeExec(LexizeData *ld, ParsedLex **correspondLexem) {
	int i;
	ListDictionary	*map;
	DictInfo *dict;
	TSLexeme	*res;

	if ( ld->curDictId == InvalidOid ) {
		/* 
		 * usial mode: dictionary wants only one word,
		 * but we should keep in mind that we should go through
		 * all stack
		 */

		while( ld->towork.head ) {
			ParsedLex	*curVal = ld->towork.head;

			map = ld->cfg->map + curVal->type;

			if (curVal->type == 0 || curVal->type >= ld->cfg->len || map->len == 0 ) {	
				/* skip this type of lexeme */
				RemoveHead(ld);
				continue;
			}

			for (i = ld->posDict; i < map->len; i++) {
				dict = finddict(DatumGetObjectId(map->dict_id[i]));

				ld->dictState.isend = ld->dictState.getnext = false;
				ld->dictState.private = NULL;
				res = (TSLexeme *) DatumGetPointer( FunctionCall4(
													&(dict->lexize_info),
									   				PointerGetDatum(dict->dictionary),
												   	PointerGetDatum(curVal->lemm),
												 	Int32GetDatum(curVal->lenlemm),
													PointerGetDatum(&ld->dictState)
										 ));

				if ( ld->dictState.getnext ) {
					/* 
					 * dictinary wants next word, so setup and store
					 * current position and go to multiword  mode
					 */
					 
					ld->curDictId = DatumGetObjectId(map->dict_id[i]);
					ld->posDict = i+1;
					ld->curSub = curVal->next;
					if ( res )
						setNewTmpRes(ld, curVal, res);
					return LexizeExec(ld, correspondLexem);
				}

				if (!res)			/* dictionary doesn't know this lexeme */
					continue;
				
				RemoveHead(ld);
				setCorrLex(ld, correspondLexem);
				return res;
			}

			RemoveHead(ld);
		} 
	} else { /* curDictId is valid */
		dict = finddict(ld->curDictId);
		
		/*
		 * Dictionary ld->curDictId asks  us about following words
		 */

		while( ld->curSub ) {
			ParsedLex	*curVal = ld->curSub;

			map = ld->cfg->map + curVal->type;

			if (curVal->type != 0) {
				bool dictExists = false;

				if (curVal->type >= ld->cfg->len || map->len == 0 ) {	
					/* skip this type of lexeme */
					ld->curSub = curVal->next;
					continue;
				}

				/*
				 * We should be sure that current type of lexeme is recognized by
				 * our dictinonary: we just check is it exist in 
				 * list of dictionaries ?
				 */
				for(i=0;i < map->len && !dictExists; i++) 
					if ( ld->curDictId == DatumGetObjectId(map->dict_id[i]) )
						dictExists = true;

				if ( !dictExists ) {
					/*
					 * Dictionary can't work with current tpe of lexeme,
					 * return to basic mode and redo all stored lexemes
					 */
					ld->curDictId = InvalidOid;
					return LexizeExec(ld, correspondLexem);
				}
			} 
	
			ld->dictState.isend = (curVal->type==0) ? true : false;
			ld->dictState.getnext = false;

			res = (TSLexeme *) DatumGetPointer( FunctionCall4(
												&(dict->lexize_info),
								   				PointerGetDatum(dict->dictionary),
											   	PointerGetDatum(curVal->lemm),
											 	Int32GetDatum(curVal->lenlemm),
												PointerGetDatum(&ld->dictState)
										 ));

			if ( ld->dictState.getnext ) {
				/* Dictionary wants one more */
				ld->curSub = curVal->next;
				if ( res )
					setNewTmpRes(ld, curVal, res);
				continue;
			}

			if ( res || ld->tmpRes ) {
				/*
				 * Dictionary normalizes lexemes,
				 * so we remove from stack all used lexemes ,
				 * return to basic mode and redo end of stack (if it exists)
				 */
				if ( res ) {
					moveToWaste( ld, ld->curSub );
				} else {
					res = ld->tmpRes;
					moveToWaste( ld, ld->lastRes );
				}

				/* reset to initial state */
				ld->curDictId = InvalidOid;
				ld->posDict = 0;
				ld->lastRes = NULL;
				ld->tmpRes = NULL;
				setCorrLex(ld, correspondLexem);
				return res;
			}

			/* Dict don't want next lexem and didn't recognize anything,
			   redo from ld->towork.head */
			ld->curDictId = InvalidOid;
			return LexizeExec(ld, correspondLexem);
		}	
	}

	setCorrLex(ld, correspondLexem);
	return NULL;
}