/*
 *  Copyright 2007-2009 Adrian Thurston <thurston@complang.org>
 */

/*  This file is part of Colm.
 *
 *  Colm is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 * 
 *  Colm 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 Colm; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */

#include <string.h>
#include <iostream>
#include <stdlib.h>

#include "config.h"
#include "fsmrun.h"
#include "pdarun.h"
#include "debug.h"

using std::cerr;
using std::endl;

exit_object endp;

void operator<<( ostream &out, exit_object & )
{
	out << endl;
	exit(1);
}

void incrementConsumed( PdaRun *pdaRun )
{
	pdaRun->consumed += 1;
	debug( REALM_PARSE, "consumed up to %ld\n", pdaRun->consumed );
}

void decrementConsumed( PdaRun *pdaRun )
{
	pdaRun->consumed -= 1;
	debug( REALM_PARSE, "consumed down to %ld\n", pdaRun->consumed );
}

void takeBackBuffered( InputStream *inputStream )
{
	if ( inputStream->hasData != 0 ) {
		FsmRun *fsmRun = inputStream->hasData;

		if ( fsmRun->runBuf != 0 ) {
			if ( fsmRun->pe - fsmRun->p > 0 ) {
				#ifdef COLM_LOG_PARSE
				if ( colm_log_parse ) {
					cerr << "taking back buffered fsmRun: " << fsmRun << 
							" input stream: " << inputStream << endl;
				}
				#endif

				RunBuf *split = newRunBuf();
				memcpy( split->data, fsmRun->p, fsmRun->pe - fsmRun->p );

				split->length = fsmRun->pe - fsmRun->p;
				split->offset = 0;
				split->next = 0;

				fsmRun->pe = fsmRun->p;

				inputStream->funcs->pushBackBuf( inputStream, split );
			}
		}

		inputStream->hasData = 0;
		fsmRun->haveDataOf = 0;
	}
}

void connect( FsmRun *fsmRun, InputStream *inputStream )
{
	if ( inputStream->hasData != 0 && inputStream->hasData != fsmRun ) {
		takeBackBuffered( inputStream );
	}
	
	if ( inputStream->hasData != fsmRun ) {
		#ifdef COLM_LOG_PARSE
		if ( colm_log_parse ) {
			cerr << "connecting fsmRun: " << fsmRun << " and input stream " <<
					inputStream << endl;
		}
		#endif
	}

	inputStream->hasData = fsmRun;
	fsmRun->haveDataOf = inputStream;
}

/* Load up a token, starting from tokstart if it is set. If not set then
 * start it at data. */
Head *streamPull( Program *prg, FsmRun *fsmRun, InputStream *inputStream, long length )
{
	/* We should not be in the midst of getting a token. */
	assert( fsmRun->tokstart == 0 );

	/* The generated token length has been stuffed into tokdata. */
	if ( fsmRun->p + length > fsmRun->pe ) {
		fsmRun->p = fsmRun->pe = fsmRun->runBuf->data;
		fsmRun->peof = 0;

		long space = fsmRun->runBuf->data + FSM_BUFSIZE - fsmRun->pe;
			
		if ( space == 0 )
			cerr << "OUT OF BUFFER SPACE" << endp;

		connect( fsmRun, inputStream );
			
		long len = inputStream->funcs->getData( inputStream, fsmRun->p, space );
		fsmRun->pe = fsmRun->p + len;
	}

	if ( fsmRun->p + length > fsmRun->pe )
		cerr << "NOT ENOUGH DATA TO FETCH TOKEN" << endp;

	Head *tokdata = stringAllocPointer( prg, fsmRun->p, length );
	updatePosition( inputStream, fsmRun->p, length );
	fsmRun->p += length;

	return tokdata;
}

void sendBackRunBufHead( FsmRun *fsmRun, InputStream *inputStream )
{
	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		cerr << "pushing back runbuf" << endl;
	}
	#endif

	/* Move to the next run buffer. */
	RunBuf *back = fsmRun->runBuf;
	fsmRun->runBuf = fsmRun->runBuf->next;
		
	/* Flush out the input buffer. */
	back->length = fsmRun->pe - fsmRun->p;
	back->offset = 0;
	inputStream->funcs->pushBackBuf( inputStream, back );

	/* Set data and de. */
	if ( fsmRun->runBuf == 0 ) {
		fsmRun->runBuf = newRunBuf();
		fsmRun->runBuf->next = 0;
		fsmRun->p = fsmRun->pe = fsmRun->runBuf->data;
	}

	fsmRun->p = fsmRun->pe = fsmRun->runBuf->data + fsmRun->runBuf->length;
}

void undoStreamPull( FsmRun *fsmRun, InputStream *inputStream, const char *data, long length )
{
	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		cerr << "undoing stream pull" << endl;
	}
	#endif

	connect( fsmRun, inputStream );

	if ( fsmRun->p == fsmRun->pe && fsmRun->p == fsmRun->runBuf->data )
		sendBackRunBufHead( fsmRun, inputStream );

	assert( fsmRun->p - length >= fsmRun->runBuf->data );
	fsmRun->p -= length;
}

void streamPushText( InputStream *inputStream, const char *data, long length )
{
//	#ifdef COLM_LOG_PARSE
//	if ( colm_log_parse ) {
//		cerr << "readying fake push" << endl;
//	}
//	#endif

	takeBackBuffered( inputStream );
	inputStream->funcs->pushText( inputStream, data, length );
}

void streamPushTree( InputStream *inputStream, Tree *tree, bool ignore )
{
//	#ifdef COLM_LOG_PARSE
//	if ( colm_log_parse ) {
//		cerr << "readying fake push" << endl;
//	}
//	#endif

	takeBackBuffered( inputStream );
	inputStream->funcs->pushTree( inputStream, tree, ignore );
}

void undoStreamPush( Program *prg, Tree **sp, InputStream *inputStream, long length )
{
	takeBackBuffered( inputStream );
	Tree *tree = inputStream->funcs->undoPush( inputStream, length );
	if ( tree != 0 )
		treeDownref( prg, sp, tree );
}

void undoStreamAppend( Program *prg, Tree **sp, InputStream *inputStream, long length )
{
	takeBackBuffered( inputStream );
	Tree *tree = inputStream->funcs->undoAppend( inputStream, length );
	if ( tree != 0 )
		treeDownref( prg, sp, tree );
}


/* Should only be sending back whole tokens/ignores, therefore the send back
 * should never cross a buffer boundary. Either we slide back data, or we move to
 * a previous buffer and slide back data. */
void sendBackText( FsmRun *fsmRun, InputStream *inputStream, const char *data, long length )
{
	connect( fsmRun, inputStream );

	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		cerr << "push back of " << length << " characters" << endl;
	}
	#endif

	if ( length == 0 )
		return;

	if ( fsmRun->p == fsmRun->runBuf->data )
		sendBackRunBufHead( fsmRun, inputStream );

	/* If there is data in the current buffer then send the whole send back
	 * should be in this buffer. */
	assert( (fsmRun->p - fsmRun->runBuf->data) >= length );

	/* slide data back. */
	fsmRun->p -= length;

	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		if ( memcmp( data, fsmRun->p, length ) != 0 )
			cerr << "mismatch of pushed back text" << endl;
	}
	#endif

	assert( memcmp( data, fsmRun->p, length ) == 0 );
		
	undoPosition( inputStream, data, length );
}

void sendBackIgnore( Tree **sp, PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream, Kid *ignore )
{
	/* Ignore tokens are queued in reverse order. */
	while ( ignore != 0 ) {
		#ifdef COLM_LOG_PARSE
		if ( colm_log_parse ) {
			LangElInfo *lelInfo = pdaRun->tables->rtd->lelInfo;
			cerr << "sending back: " << lelInfo[ignore->tree->id].name;
			if ( ignore->tree->flags & AF_ARTIFICIAL )
				cerr << " (artificial)";
			cerr << endl;
		}
		#endif

		Head *head = ignore->tree->tokdata;
		bool artificial = ignore->tree->flags & AF_ARTIFICIAL;

		if ( head != 0 && !artificial )
			sendBackText( fsmRun, inputStream, stringData( head ), head->length );

		decrementConsumed( pdaRun );

		/* Check for reverse code. */
		if ( ignore->tree->flags & AF_HAS_RCODE ) {
			Execution exec;
			initExecution( &exec, pdaRun->prg, &pdaRun->reverseCode, 
					pdaRun, fsmRun, 0, 0, 0, 0, 0 );

			/* Do the reverse exeuction. */
			rexecute( &exec, sp, pdaRun->allReverseCode );
			ignore->tree->flags &= ~AF_HAS_RCODE;
		}

		ignore = ignore->next;
	}
}


void sendBack( Tree **sp, PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream, Kid *input )
{
	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		LangElInfo *lelInfo = pdaRun->tables->rtd->lelInfo;
		cerr << "sending back: " << lelInfo[input->tree->id].name << "  text: ";
		cerr.write( stringData( input->tree->tokdata ), 
				stringLength( input->tree->tokdata ) );
		if ( input->tree->flags & AF_ARTIFICIAL )
			cerr << " (artificial)";
		cerr << endl;
	}
	#endif

	if ( input->tree->flags & AF_NAMED ) {
		/* Send back anything in the buffer that has not been parsed. */
		if ( fsmRun->p == fsmRun->runBuf->data )
			sendBackRunBufHead( fsmRun, inputStream );

		/* Send the named lang el back first, then send back any leading
		 * whitespace. */
		inputStream->funcs->pushBackNamed( inputStream );
	}

	decrementConsumed( pdaRun );

	if ( input->tree->flags & AF_ARTIFICIAL ) {
		treeUpref( input->tree );
		streamPushTree( inputStream, input->tree, false );

		/* FIXME: need to undo the merge of ignore tokens. */
		Kid *leftIgnore = 0;
		if ( input->tree->flags & AF_LEFT_IGNORE ) {
			leftIgnore = (Kid*)input->tree->child->tree;
			//input->tree->flags &= ~AF_LEFT_IGNORE;
			//input->tree->child = input->tree->child->next;
		}

		//if ( input->tree->flags & AF_RIGHT_IGNORE ) {
		//	cerr << "need to pull out ignore" << endl;
		//}

		sendBackIgnore( sp, pdaRun, fsmRun, inputStream, leftIgnore );

		///* Always push back the ignore text. */
		//sendBackIgnore( sp, pdaRun, fsmRun, inputStream, treeIgnore( fsmRun->prg, input->tree ) );
	}
	else {
		/* Push back the token data. */
		sendBackText( fsmRun, inputStream, stringData( input->tree->tokdata ), 
				stringLength( input->tree->tokdata ) );

		/* Check for reverse code. */
		if ( input->tree->flags & AF_HAS_RCODE ) {
			Execution exec;
			initExecution( &exec, pdaRun->prg, &pdaRun->reverseCode, 
					pdaRun, fsmRun, 0, 0, 0, 0, 0 );

			/* Do the reverse exeuction. */
			rexecute( &exec, sp, pdaRun->allReverseCode );
			input->tree->flags &= ~AF_HAS_RCODE;
		}

		/* Always push back the ignore text. */
		sendBackIgnore( sp, pdaRun, fsmRun, inputStream, treeIgnore( fsmRun->prg, input->tree ) );

		/* If eof was just sent back remember that it needs to be sent again. */
		if ( input->tree->id == pdaRun->tables->rtd->eofLelIds[pdaRun->parserId] )
			inputStream->eofSent = false;

		/* If the item is bound then store remove it from the bindings array. */
		Tree *lastBound = pdaRun->bindings.top();
		if ( lastBound == input->tree ) {
			pdaRun->bindings.pop();
			treeDownref( fsmRun->prg, sp, input->tree );
		}
	}

	if ( pdaRun->consumed == pdaRun->targetConsumed ) {
		#ifdef COLM_LOG_PARSE
		if ( colm_log_parse )
			cerr << "trigger parse stop, consumed = target = " << pdaRun->targetConsumed << endl;
		#endif
			
		pdaRun->stop = true;
	}

	/* Downref the tree that was sent back and free the kid. */
	treeDownref( fsmRun->prg, sp, input->tree );
	kidFree( fsmRun->prg, input );
}


/* This is the entry point for the perser to send back tokens. */
void queueBackTree( Tree **sp, PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream, Kid *input )
{
	/* If there are queued items send them back starting at the tail
	 * (newest). */
	if ( pdaRun->queue != 0 ) {
		/* Reverse the list. */
		Kid *kid = pdaRun->queue, *last = 0;
		while ( kid != 0 ) {
			Kid *next = kid->next;
			kid->next = last;
			last = kid;
			kid = next;
		}

		/* Send them back. */
		while ( last != 0 ) {
			Kid *next = last->next;
			sendBack( sp, pdaRun, fsmRun, inputStream, last );
			last = next;
		}

		pdaRun->queue = 0;
	}

	/* Now that the queue is flushed, can send back the original item. */
	sendBack( sp, pdaRun, fsmRun, inputStream, input );
}

/* If no token was generated but there is reverse code then we must generate
 * a fake token so we can attach the reverse code to it. */
void addNoToken( Program *prg, PdaRun *parser )
{
	/* Check if there was anything generated. */
	if ( parser->queue == 0 && parser->reverseCode.length() > 0 ) {
		#ifdef COLM_LOG_PARSE
		if ( colm_log_parse ) {
			cerr << "found reverse code but no token, sending _notoken" << endl;
		}
		#endif

		Tree *tree = (Tree*)parseTreeAllocate( prg );
		tree->flags |= AF_PARSE_TREE;
		tree->refs = 1;
		tree->id = prg->rtd->noTokenId;
		tree->tokdata = 0;

		parser->queue = kidAllocate( prg );
		parser->queue->tree = tree;
		parser->queue->next = 0;
	}
}

void sendQueuedTokens( Tree **sp, PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream )
{
	LangElInfo *lelInfo = fsmRun->prg->rtd->lelInfo;

	while ( pdaRun->queue != 0 ) {
		/* Pull an item to send off the queue. */
		Kid *send = pdaRun->queue;
		pdaRun->queue = pdaRun->queue->next;

		/* Must clear next, since the parsing algorithm uses it. */
		send->next = 0;
		if ( lelInfo[send->tree->id].ignore ) {
			#ifdef COLM_LOG_PARSE
			if ( colm_log_parse ) {
				cerr << "ignoring queued item: " << 
						pdaRun->tables->rtd->lelInfo[send->tree->id].name << endl;
			}
			#endif

			incrementConsumed( pdaRun );

			ignore( pdaRun, send->tree );
			kidFree( fsmRun->prg, send );
		}
		else {
			#ifdef COLM_LOG_PARSE
			if ( colm_log_parse ) {
				cerr << "sending queue item: " << 
						pdaRun->tables->rtd->lelInfo[send->tree->id].name << endl;
			}
			#endif

			incrementConsumed( pdaRun );

			sendHandleError( sp, pdaRun, fsmRun, inputStream, send );
		}
	}
}

Kid *makeToken( PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream, int id,
		Head *tokdata, bool namedLangEl, int bindId )
{
	/* Make the token object. */
	long objectLength = pdaRun->tables->rtd->lelInfo[id].objectLength;
	Kid *attrs = allocAttrs( fsmRun->prg, objectLength );

	Kid *input = 0;
	input = kidAllocate( fsmRun->prg );
	input->tree = (Tree*)parseTreeAllocate( fsmRun->prg );
	input->tree->flags |= AF_PARSE_TREE;

	if ( namedLangEl )
		input->tree->flags |= AF_NAMED;

	input->tree->refs = 1;
	input->tree->id = id;
	input->tree->tokdata = tokdata;

	/* No children and ignores get added later. */
	input->tree->child = attrs;

	LangElInfo *lelInfo = pdaRun->tables->rtd->lelInfo;
	if ( lelInfo[id].numCaptureAttr > 0 ) {
		for ( int i = 0; i < lelInfo[id].numCaptureAttr; i++ ) {
			CaptureAttr *ca = &pdaRun->tables->rtd->captureAttr[lelInfo[id].captureAttr + i];
			Head *data = stringAllocFull( fsmRun->prg, 
					fsmRun->mark[ca->mark_enter], fsmRun->mark[ca->mark_leave]
					- fsmRun->mark[ca->mark_enter] );
			Tree *string = constructString( fsmRun->prg, data );
			treeUpref( string );
			setAttr( input->tree, ca->offset, string );
		}
	}
	
	/* If the item is bound then store it in the bindings array. */
	if ( bindId > 0 ) {
		pdaRun->bindings.push( input->tree );
		treeUpref( input->tree );
	}

	return input;
}

void executeGenerationAction( Tree **sp, Program *prg, FsmRun *fsmRun, PdaRun *pdaRun, 
		Code *code, long id, Head *tokdata )
{
	/* Execute the translation. */
	Execution exec;
	initExecution( &exec, prg, &pdaRun->reverseCode, pdaRun, fsmRun, code, 0, id, tokdata, fsmRun->mark );
	execute( &exec, sp );

	/* If there is revese code but nothing generated we need a noToken. */
	addNoToken( prg, pdaRun );

	/* If there is reverse code then addNoToken will guarantee that the
	 * queue is not empty. Pull the reverse code out and store in the
	 * token. */
	Tree *tree = pdaRun->queue->tree;
	bool hasrcode = makeReverseCode( pdaRun->allReverseCode, pdaRun->reverseCode );
	if ( hasrcode )
		tree->flags |= AF_HAS_RCODE;
}

/* 
 * Not supported:
 *  -invoke failure (the backtracker)
 */

void generationAction( Tree **sp, InputStream *inputStream, FsmRun *fsmRun, 
		PdaRun *pdaRun, int id, Head *tokdata, bool namedLangEl, int bindId )
{
	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		cerr << "generation action: " << 
				pdaRun->tables->rtd->lelInfo[id].name << endl;
	}
	#endif

	/* Find the code. */
	Code *code = pdaRun->tables->rtd->frameInfo[
			pdaRun->tables->rtd->lelInfo[id].frameId].codeWV;

	/* Execute the action and process the queue. */
	executeGenerationAction( sp, fsmRun->prg, fsmRun, pdaRun, code, id, tokdata );

	/* Finished with the match text. */
	stringFree( fsmRun->prg, tokdata );

	/* Send the queued tokens. */
	sendQueuedTokens( sp, pdaRun, fsmRun, inputStream );
}

Kid *extractIgnore( PdaRun *pdaRun )
{
	Kid *ignore = pdaRun->accumIgnore;
	pdaRun->accumIgnore = 0;
	return ignore;
}

/* Send back the accumulated ignore tokens. */
void sendBackQueuedIgnore( Tree **sp, InputStream *inputStream, FsmRun *fsmRun, PdaRun *pdaRun )
{
	Kid *ignore = extractIgnore( pdaRun );
	sendBackIgnore( sp, pdaRun, fsmRun, inputStream, ignore );
	while ( ignore != 0 ) {
		Kid *next = ignore->next;
		treeDownref( pdaRun->prg, sp, ignore->tree );
		kidFree( pdaRun->prg, ignore );
		ignore = next;
	}
}

void clearIgnoreList( Program *prg, Tree **sp, Kid *kid )
{
	while ( kid != 0 ) {
		Kid *next = kid->next;
		treeDownref( prg, sp, kid->tree );
		kidFree( prg, kid );
		kid = next;
	}
}

void sendWithIgnore( Tree **sp, PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream, Kid *input )
{
	/* Need to preserve the layout under a tree:
	 *    attributes, ignore tokens, grammar children. */

	/* Pull the ignore tokens out and store in the token. */
	Kid *ignore = extractIgnore( pdaRun );
	if ( ignore != 0 ) {
		if ( input->tree->flags & AF_LEFT_IGNORE ) {
			/* FIXME: Leak here. */
			Kid *ignoreHead = input->tree->child;
			clearIgnoreList( pdaRun->prg, sp, (Kid*) ignoreHead->tree );
			ignoreHead->tree = (Tree*) ignore;
		}
		else {
			/* Insert an ignore head in the child list. */
			Kid *ignoreHead = kidAllocate( pdaRun->prg );
			ignoreHead->next = input->tree->child;
			input->tree->child = ignoreHead;

			ignoreHead->tree = (Tree*) ignore;
			input->tree->flags |= AF_LEFT_IGNORE;
		}
	}
	else {
		/* Need to remove any existing ignore data. */
		if ( input->tree->flags & AF_LEFT_IGNORE ) {
			/* FIXME: leak here. */
			Kid *ignoreHead = input->tree->child;
			clearIgnoreList( pdaRun->prg, sp, (Kid*)ignoreHead->tree );
			kidFree( pdaRun->prg, ignoreHead );

			input->tree->child = input->tree->child->next;
			input->tree->flags = input->tree->flags & ~AF_LEFT_IGNORE ;
		}
	}

	parseToken( sp, pdaRun, fsmRun, inputStream, input );
}

void sendHandleError( Tree **sp, PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream, Kid *input )
{
	long id = input->tree->id;

	/* Send the token to the parser. */
	sendWithIgnore( sp, pdaRun, fsmRun, inputStream, input );
		
	/* Check the result. */
	if ( pdaRun->errCount > 0 ) {
		/* Error occured in the top-level parser. */
		parseError( inputStream, fsmRun, pdaRun, id, input->tree ) << "parse error" << endp;
	}
	else {
		if ( isParserStopFinished( pdaRun ) ) {
			#ifdef COLM_LOG_PARSE
			if ( colm_log_parse ) {
				cerr << "stopping the parse" << endl;
			}
			#endif
			pdaRun->stopParsing = true;
		}
	}
}

void ignore( PdaRun *pdaRun, Tree *tree )
{
	/* Add the ignore string to the head of the ignore list. */
	Kid *ignore = kidAllocate( pdaRun->prg );
	ignore->tree = tree;

	/* Prepend it to the list of ignore tokens. */
	ignore->next = pdaRun->accumIgnore;
	pdaRun->accumIgnore = ignore;
}

void execGen( Tree **sp, InputStream *inputStream, FsmRun *fsmRun, PdaRun *pdaRun, long id )
{
	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		cerr << "token gen action: " << pdaRun->tables->rtd->lelInfo[id].name << endl;
	}
	#endif

	/* Make the token data. */
	Head *tokdata = extractMatch( pdaRun->prg, fsmRun, inputStream );

	/* Note that we don't update the position now. It is done when the token
	 * data is pulled from the inputStream. */

	fsmRun->p = fsmRun->tokstart;
	fsmRun->tokstart = 0;

	generationAction( sp, inputStream, fsmRun, pdaRun, id, tokdata, false, 0 );
}

void sendIgnore( InputStream *inputStream, FsmRun *fsmRun, PdaRun *pdaRun, long id )
{
	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		cerr << "ignoring: " << pdaRun->tables->rtd->lelInfo[id].name << endl;
	}
	#endif

	/* Make the ignore string. */
	Head *ignoreStr = extractMatch( pdaRun->prg, fsmRun, inputStream );
	updatePosition( inputStream, fsmRun->tokstart, ignoreStr->length );
	
	Tree *tree = treeAllocate( fsmRun->prg );
	tree->refs = 1;
	tree->id = id;
	tree->tokdata = ignoreStr;

	incrementConsumed( pdaRun );

	/* Send it to the pdaRun. */
	ignore( pdaRun, tree );
}

Head *extractMatch( Program *prg, FsmRun *fsmRun, InputStream *inputStream )
{
	long length = fsmRun->p - fsmRun->tokstart;
	Head *head = stringAllocPointer( prg, fsmRun->tokstart, length );
	head->location = locationAllocate( prg );
	head->location->line = inputStream->line;
	head->location->column = inputStream->column;
	head->location->byte = inputStream->byte;
	return head;
}

void sendToken( Tree **sp, InputStream *inputStream, FsmRun *fsmRun, PdaRun *pdaRun, long id )
{
	/* Make the token data. */
	Head *tokdata = extractMatch( pdaRun->prg, fsmRun, inputStream );

	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		cerr << "token: " << pdaRun->tables->rtd->lelInfo[id].name << "  text: ";
		cerr.write( stringData( tokdata ), stringLength( tokdata ) );
		cerr << endl;
	}
	#endif

	updatePosition( inputStream, fsmRun->tokstart, tokdata->length );

	Kid *input = makeToken( pdaRun, fsmRun, inputStream, id, tokdata, false, 0 );

	incrementConsumed( pdaRun );

	sendHandleError( sp, pdaRun, fsmRun, inputStream, input );
}


void sendEof( Tree **sp, InputStream *inputStream, FsmRun *fsmRun, PdaRun *pdaRun )
{
	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		cerr << "token: _EOF" << endl;
	}
	#endif

	incrementConsumed( pdaRun );

	Kid *input = kidAllocate( fsmRun->prg );
	input->tree = (Tree*)parseTreeAllocate( fsmRun->prg );
	input->tree->flags |= AF_PARSE_TREE;

	input->tree->refs = 1;
	input->tree->id = pdaRun->tables->rtd->eofLelIds[pdaRun->parserId];

	/* Set the state using the state of the parser. */
	fsmRun->region = pdaRunGetNextRegion( pdaRun, 0 );
	fsmRun->cs = fsmRun->tables->entryByRegion[fsmRun->region];

	bool ctxDepParsing = fsmRun->prg->ctxDepParsing;
	long frameId = pdaRun->tables->rtd->regionInfo[fsmRun->region].eofFrameId;
	if ( ctxDepParsing && frameId >= 0 ) {
		#ifdef COLM_LOG_PARSE
		if ( colm_log_parse ) {
			cerr << "HAVE PRE_EOF BLOCK" << endl;
		}
		#endif

		/* Get the code for the pre-eof block. */
		Code *code = pdaRun->tables->rtd->frameInfo[frameId].codeWV;

		/* Execute the action and process the queue. */
		executeGenerationAction( sp, fsmRun->prg, fsmRun, pdaRun, code, input->tree->id, 0 );

		/* Send the generated tokens. */
		sendQueuedTokens( sp, pdaRun, fsmRun, inputStream );
	}

	sendWithIgnore( sp, pdaRun, fsmRun, inputStream, input );

	if ( pdaRun->errCount > 0 ) {
		parseError( inputStream, fsmRun, pdaRun, input->tree->id, input->tree ) << 
				"parse error" << endp;
	}
}

void initInputStream( InputStream *inputStream )
{
	/* FIXME: correct values here. */
	inputStream->line = 0;
	inputStream->column = 0;
	inputStream->byte = 0;
}

void newToken( PdaRun *pdaRun, FsmRun *fsmRun )
{
	/* Init the scanner vars. */
	fsmRun->act = 0;
	fsmRun->tokstart = 0;
	fsmRun->tokend = 0;
	fsmRun->matchedToken = 0;
	fsmRun->tokstart = 0;

	/* Set the state using the state of the parser. */
	fsmRun->region = pdaRunGetNextRegion( pdaRun, 0 );
	fsmRun->cs = fsmRun->tables->entryByRegion[fsmRun->region];

	#ifdef COLM_LOG_PARSE
	if ( colm_log_parse ) {
		cerr << "scanning using token region: " << 
				pdaRun->tables->rtd->regionInfo[fsmRun->region].name << endl;
	}
	#endif

	/* Clear the mark array. */
	memset( fsmRun->mark, 0, sizeof(fsmRun->mark) );
}

void breakRunBuf( FsmRun *fsmRun )
{
	/* We break the runbuf on named language elements and trees. This makes
	 * backtracking simpler because it allows us to always push back whole
	 * runBufs only. If we did not do this we could get half a runBuf, a named
	 * langEl, then the second half full. During backtracking we would need to
	 * push the halves back separately. */
	if ( fsmRun->p > fsmRun->runBuf->data ) {
		#ifdef COLM_LOG_PARSE
		if ( colm_log_parse )
			cerr << "have a langEl, making a new runBuf" << endl;
		#endif

		/* Compute the length of the current before before we move
		 * past it. */
		fsmRun->runBuf->length = fsmRun->p - fsmRun->runBuf->data;;

		/* Make the new one. */
		RunBuf *newBuf = newRunBuf();
		fsmRun->p = fsmRun->pe = newBuf->data;
		newBuf->next = fsmRun->runBuf;
		fsmRun->runBuf = newBuf;
	}
}

#define SCAN_IGNORE            -6
#define SCAN_TREE              -5
#define SCAN_TRY_AGAIN_LATER   -4
#define SCAN_ERROR             -3
#define SCAN_LANG_EL           -2
#define SCAN_EOF               -1

long scanToken( PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream )
{
	while ( true ) {
		if ( inputStream->funcs->needFlush( inputStream ) )
			fsmRun->peof = fsmRun->pe;

		fsmExecute( fsmRun, inputStream );

		/* First check if scanning stopped because we have a token. */
		if ( fsmRun->matchedToken > 0 ) {
			/* If the token has a marker indicating the end (due to trailing
			 * context) then adjust data now. */
			LangElInfo *lelInfo = pdaRun->tables->rtd->lelInfo;
			if ( lelInfo[fsmRun->matchedToken].markId >= 0 )
				fsmRun->p = fsmRun->mark[lelInfo[fsmRun->matchedToken].markId];

			return fsmRun->matchedToken;
		}

		/* Check for error. */
		if ( fsmRun->cs == fsmRun->tables->errorState ) {
			/* If a token was started, but not finished (tokstart != 0) then
			 * restore data to the beginning of that token. */
			if ( fsmRun->tokstart != 0 )
				fsmRun->p = fsmRun->tokstart;

			/* Check for a default token in the region. If one is there
			 * then send it and continue with the processing loop. */
			if ( pdaRun->tables->rtd->regionInfo[fsmRun->region].defaultToken >= 0 ) {
				fsmRun->tokstart = fsmRun->tokend = fsmRun->p;
				return pdaRun->tables->rtd->regionInfo[fsmRun->region].defaultToken;
			}

			return SCAN_ERROR;
		}

		/* Got here because the state machine didn't match a token or
		 * encounter an error. Must be because we got to the end of the buffer
		 * data. */
		assert( fsmRun->p == fsmRun->pe );

		/* Check for a named language element or constructed trees. Note that
		 * we can do this only when data == de otherwise we get ahead of what's
		 * already in the buffer. */
		if ( inputStream->funcs->isLangEl( inputStream ) ) {
			breakRunBuf( fsmRun );
			return SCAN_LANG_EL;
		}
		else if ( inputStream->funcs->isTree( inputStream ) ) {
			breakRunBuf( fsmRun );
			return SCAN_TREE;
		}
		else if ( inputStream->funcs->isIgnore( inputStream ) ) {
			breakRunBuf( fsmRun );
			return SCAN_IGNORE;
		}

		/* Maybe need eof. */
 		if ( inputStream->funcs->isEof( inputStream ) ) {
			if ( fsmRun->tokstart != 0 ) {
				/* If a token has been started, but not finshed 
				 * this is an error. */
				fsmRun->cs = fsmRun->tables->errorState;
				return SCAN_ERROR;
			}
			else {
				return SCAN_EOF;
			}
		}

		/* Maybe need to pause parsing until more data is inserted into the
		 * input inputStream. */
		if ( inputStream->funcs->tryAgainLater( inputStream ) )
			return SCAN_TRY_AGAIN_LATER;

		/* There may be space left in the current buffer. If not then we need
		 * to make some. */
		long space = fsmRun->runBuf->data + FSM_BUFSIZE - fsmRun->pe;
		if ( space == 0 ) {
			/* Create a new run buf. */
			RunBuf *newBuf = newRunBuf();

			/* If partway through a token then preserve the prefix. */
			long have = 0;

			if ( fsmRun->tokstart == 0 ) {
				/* No prefix. We filled the previous buffer. */
				fsmRun->runBuf->length = FSM_BUFSIZE;
			}
			else {
				if ( fsmRun->tokstart == fsmRun->runBuf->data ) {
					/* A token is started and it is already at the beginning
					 * of the current buffer. This means buffer is full and it
					 * must be grown. Probably need to do this sooner. */
					cerr << "OUT OF BUFFER SPACE" << endp;
				}

				/* There is data that needs to be shifted over. */
				have = fsmRun->pe - fsmRun->tokstart;
				memcpy( newBuf->data, fsmRun->tokstart, have );

				/* Compute the length of the previous buffer. */
				fsmRun->runBuf->length = FSM_BUFSIZE - have;

				/* Compute tokstart and tokend. */
				long dist = fsmRun->tokstart - newBuf->data;

				fsmRun->tokend -= dist;
				fsmRun->tokstart = newBuf->data;

				/* Shift any markers. */
				for ( int i = 0; i < MARK_SLOTS; i++ ) {
					if ( fsmRun->mark[i] != 0 )
						fsmRun->mark[i] -= dist;
				}
			}

			fsmRun->p = fsmRun->pe = newBuf->data + have;
			fsmRun->peof = 0;

			newBuf->next = fsmRun->runBuf;
			fsmRun->runBuf = newBuf;
		}

		/* We don't have any data. What is next in the input inputStream? */
		space = fsmRun->runBuf->data + FSM_BUFSIZE - fsmRun->pe;
		assert( space > 0 );
			
		connect( fsmRun, inputStream );

		/* Get more data. */
		int len = inputStream->funcs->getData( inputStream, fsmRun->p, space );
		fsmRun->pe = fsmRun->p + len;
	}

	/* Should not be reached. */
	return SCAN_ERROR;
}

void scannerError( Tree **sp, InputStream *inputStream, FsmRun *fsmRun, PdaRun *pdaRun )
{
	if ( pdaRunGetNextRegion( pdaRun, 1 ) != 0 ) {
		#ifdef COLM_LOG_PARSE
		if ( colm_log_parse ) {
			cerr << "scanner failed, trying next region" << endl;
		}
		#endif

		/* May have accumulated ignore tokens from a previous region.
		 * need to rescan them since we won't be sending tokens from
		 * this region. */
		sendBackQueuedIgnore( sp, inputStream, fsmRun, pdaRun );
		pdaRun->nextRegionInd += 1;
	}
	else if ( pdaRun->numRetry > 0 ) {
		/* Invoke the parser's error handling. */
		#ifdef COLM_LOG_PARSE
		if ( colm_log_parse ) {
			cerr << "invoking parse error from the scanner" << endl;
		}
		#endif

		sendBackQueuedIgnore( sp, inputStream, fsmRun, pdaRun );
		parseToken( sp, pdaRun, fsmRun, inputStream, 0 );

		if ( pdaRun->errCount > 0 ) {
			/* Error occured in the top-level parser. */
			cerr << "PARSE ERROR" << endp;
		}
	}
	else {
		/* There are no alternative scanning regions to try, nor are there any
		 * alternatives stored in the current parse tree. No choice but to
		 * kill the parse. */
		cerr << "error:" << inputStream->line << ": scanner error" << endp;
	}
}

void sendTree( Tree **sp, PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream )
{
//	RunBuf *runBuf = inputStream->queue;
//	inputStream->queue = inputStream->queue->next;
//
//	/* FIXME: using runbufs here for this is a poor use of memory. */
//	input->tree = runBuf->tree;
//	delete runBuf;
	Kid *input = kidAllocate( fsmRun->prg );
	input->tree = inputStream->funcs->getTree( inputStream );

	incrementConsumed( pdaRun );

	sendHandleError( sp, pdaRun, fsmRun, inputStream, input );
}

void sendTreeIgnore( Tree **sp, PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream )
{
	RunBuf *runBuf = inputStreamPopHead( inputStream );

	/* FIXME: using runbufs here for this is a poor use of memory. */
	Tree *tree = runBuf->tree;
	delete runBuf;

	incrementConsumed( pdaRun );

	ignore( pdaRun, tree );
}

void parseLoop( Tree **sp, PdaRun *pdaRun, FsmRun *fsmRun, InputStream *inputStream )
{
	pdaRun->stop = false;

	while ( true ) {
		/* Pull the current scanner from the parser. This can change during
		 * parsing due to inputStream pushes, usually for the purpose of includes.
		 * */
		int tokenId = scanToken( pdaRun, fsmRun, inputStream );

		if ( tokenId == SCAN_TRY_AGAIN_LATER )
			break;

		/* Check for EOF. */
		if ( tokenId == SCAN_EOF ) {
			inputStream->eofSent = true;
			sendEof( sp, inputStream, fsmRun, pdaRun );

			newToken( pdaRun, fsmRun );

			if ( inputStream->eofSent )
				break;
			continue;
		}

		if ( tokenId == SCAN_ERROR ) {
			/* Error. */
			scannerError( sp, inputStream, fsmRun, pdaRun );
		}
		else if ( tokenId == SCAN_LANG_EL ) {
			/* A named language element (parsing colm program). */
			sendNamedLangEl( sp, pdaRun, fsmRun, inputStream );
		}
		else if ( tokenId == SCAN_TREE ) {
			/* A tree already built. */
			sendTree( sp, pdaRun, fsmRun, inputStream );
		}
		else if ( tokenId == SCAN_IGNORE ) {
			/* A tree to ignore. */
			sendTreeIgnore( sp, pdaRun, fsmRun, inputStream );
		}
		else {
			/* Plain token. */
			bool ctxDepParsing = fsmRun->prg->ctxDepParsing;
			LangElInfo *lelInfo = pdaRun->tables->rtd->lelInfo;
			if ( ctxDepParsing && lelInfo[tokenId].frameId >= 0 )
				execGen( sp, inputStream, fsmRun, pdaRun, tokenId );
			else if ( lelInfo[tokenId].ignore )
				sendIgnore( inputStream, fsmRun, pdaRun, tokenId );
			else
				sendToken( sp, inputStream, fsmRun, pdaRun, tokenId );
		}

		newToken( pdaRun, fsmRun );

		/* Fall through here either when the input buffer has been exhausted
		 * or the scanner is in an error state. Otherwise we must continue. */
		if ( pdaRun->stopParsing ) {
			#ifdef COLM_LOG_PARSE
			if ( colm_log_parse ) {
				cerr << "scanner has been stopped" << endl;
			}
			#endif
			break;
		}

		if ( pdaRun->stop ) {
			cerr << "parsing has been stopped by consumedCount" << endl;
			break;
		}
	}
}