///////////////////////////////////////////////////////////////////////
// File:        resultiterator.cpp
// Description: Iterator for tesseract results that is capable of
//              iterating in proper reading order over Bi Directional
//              (e.g. mixed Hebrew and English) text.
// Author:      David Eger
// Created:     Fri May 27 13:58:06 PST 2011
//
// (C) Copyright 2011, Google Inc.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
///////////////////////////////////////////////////////////////////////

#include "resultiterator.h"

#include "allheaders.h"
#include "pageres.h"
#include "strngs.h"
#include "tesseractclass.h"
#include "unicharset.h"
#include "unicodes.h"

namespace tesseract {

	ResultIterator::ResultIterator(const LTRResultIterator &resit)
		: LTRResultIterator(resit) {
		in_minor_direction_ = false;
		at_beginning_of_minor_run_ = false;
		preserve_interword_spaces_ = false;

		BoolParam *p = ParamUtils::FindParam<BoolParam>(
			"preserve_interword_spaces", GlobalParams()->bool_params,
			tesseract_->params()->bool_params);
		if (p != NULL) preserve_interword_spaces_ = (bool)(*p);

		current_paragraph_is_ltr_ = CurrentParagraphIsLtr();
		MoveToLogicalStartOfTextline();
	}

	ResultIterator *ResultIterator::StartOfParagraph(
		const LTRResultIterator &resit) {
		return new ResultIterator(resit);
	}

	bool ResultIterator::ParagraphIsLtr() const {
		return current_paragraph_is_ltr_;
	}

	bool ResultIterator::CurrentParagraphIsLtr() const {
		if (!it_->word())
			return true;  // doesn't matter.
		LTRResultIterator it(*this);
		it.RestartParagraph();
		// Try to figure out the ltr-ness of the paragraph.  The rules below
		// make more sense in the context of a difficult paragraph example.
		// Here we denote {ltr characters, RTL CHARACTERS}:
		//
		//   "don't go in there!" DAIS EH
		//   EHT OTNI DEPMUJ FELSMIH NEHT DNA
		//                  .GNIDLIUB GNINRUB
		//
		// On the first line, the left-most word is LTR and the rightmost word
		// is RTL.  Thus, we are better off taking the majority direction for
		// the whole paragraph contents.  So instead of "the leftmost word is LTR"
		// indicating an LTR paragraph, we use a heuristic about what RTL paragraphs
		// would not do:  Typically an RTL paragraph would *not* start with an LTR
		// word.  So our heuristics are as follows:
		//
		// (1) If the first text line has an RTL word in the left-most position
		//     it is RTL.
		// (2) If the first text line has an LTR word in the right-most position
		//     it is LTR.
		// (3) If neither of the above is true, take the majority count for the
		//     paragraph -- if there are more rtl words, it is RTL.  If there
		//     are more LTR words, it's LTR.
		bool leftmost_rtl = it.WordDirection() == DIR_RIGHT_TO_LEFT;
		bool rightmost_ltr = it.WordDirection() == DIR_LEFT_TO_RIGHT;
		int num_ltr, num_rtl;
		num_rtl = leftmost_rtl ? 1 : 0;
		num_ltr = (it.WordDirection() == DIR_LEFT_TO_RIGHT) ? 1 : 0;
		for (it.Next(RIL_WORD);
			!it.Empty(RIL_WORD) && !it.IsAtBeginningOf(RIL_TEXTLINE);
			it.Next(RIL_WORD)) {
			StrongScriptDirection dir = it.WordDirection();
			rightmost_ltr = (dir == DIR_LEFT_TO_RIGHT);
			num_rtl += (dir == DIR_RIGHT_TO_LEFT) ? 1 : 0;
			num_ltr += rightmost_ltr ? 1 : 0;
		}
		if (leftmost_rtl)
			return false;
		if (rightmost_ltr)
			return true;
		// First line is ambiguous.  Take statistics on the whole paragraph.
		if (!it.Empty(RIL_WORD) && !it.IsAtBeginningOf(RIL_PARA)) do {
			StrongScriptDirection dir = it.WordDirection();
			num_rtl += (dir == DIR_RIGHT_TO_LEFT) ? 1 : 0;
			num_ltr += (dir == DIR_LEFT_TO_RIGHT) ? 1 : 0;
		} while (it.Next(RIL_WORD) && !it.IsAtBeginningOf(RIL_PARA));
		return num_ltr >= num_rtl;
	}

	const int ResultIterator::kMinorRunStart = -1;
	const int ResultIterator::kMinorRunEnd = -2;
	const int ResultIterator::kComplexWord = -3;

	void ResultIterator::CalculateBlobOrder(
		GenericVector<int> *blob_indices) const {
		bool context_is_ltr = current_paragraph_is_ltr_ ^ in_minor_direction_;
		blob_indices->clear();
		if (Empty(RIL_WORD)) return;
		if (context_is_ltr || it_->word()->UnicharsInReadingOrder()) {
			// Easy! just return the blobs in order;
			for (int i = 0; i < word_length_; i++)
				blob_indices->push_back(i);
			return;
		}

		// The blobs are in left-to-right order, but the current reading context
		// is right-to-left.
		const int U_LTR = UNICHARSET::U_LEFT_TO_RIGHT;
		const int U_RTL = UNICHARSET::U_RIGHT_TO_LEFT;
		const int U_EURO_NUM = UNICHARSET::U_EUROPEAN_NUMBER;
		const int U_EURO_NUM_SEP = UNICHARSET::U_EUROPEAN_NUMBER_SEPARATOR;
		const int U_EURO_NUM_TERM = UNICHARSET::U_EUROPEAN_NUMBER_TERMINATOR;
		const int U_COMMON_NUM_SEP = UNICHARSET::U_COMMON_NUMBER_SEPARATOR;
		const int U_OTHER_NEUTRAL = UNICHARSET::U_OTHER_NEUTRAL;

		// Step 1: Scan for and mark European Number sequences
		//   [:ET:]*[:EN:]+(([:ES:]|[:CS:])?[:EN:]+)*[:ET:]*
		GenericVector<int> letter_types;
		for (int i = 0; i < word_length_; i++) {
			letter_types.push_back(it_->word()->SymbolDirection(i));
		}
		// Convert a single separtor sandwiched between two EN's into an EN.
		for (int i = 0; i + 2 < word_length_; i++) {
			if (letter_types[i] == U_EURO_NUM && letter_types[i + 2] == U_EURO_NUM &&
				(letter_types[i + 1] == U_EURO_NUM_SEP ||
					letter_types[i + 1] == U_COMMON_NUM_SEP)) {
				letter_types[i + 1] = U_EURO_NUM;
			}
		}
		// Scan for sequences of European Number Terminators around ENs and convert
		// them to ENs.
		for (int i = 0; i < word_length_; i++) {
			if (letter_types[i] == U_EURO_NUM_TERM) {
				int j = i + 1;
				while (j < word_length_ && letter_types[j] == U_EURO_NUM_TERM) { j++; }
				if (j < word_length_ && letter_types[j] == U_EURO_NUM) {
					// The sequence [i..j] should be converted to all European Numbers.
					for (int k = i; k < j; k++) letter_types[k] = U_EURO_NUM;
				}
				j = i - 1;
				while (j > -1 && letter_types[j] == U_EURO_NUM_TERM) { j--; }
				if (j > -1 && letter_types[j] == U_EURO_NUM) {
					// The sequence [j..i] should be converted to all European Numbers.
					for (int k = j; k <= i; k++) letter_types[k] = U_EURO_NUM;
				}
			}
		}
		// Step 2: Convert all remaining types to either L or R.
		// Sequences ([:L:]|[:EN:])+ (([:CS:]|[:ON:])+ ([:L:]|[:EN:])+)* -> L.
		// All other are R.
		for (int i = 0; i < word_length_;) {
			int ti = letter_types[i];
			if (ti == U_LTR || ti == U_EURO_NUM) {
				// Left to right sequence; scan to the end of it.
				int last_good = i;
				for (int j = i + 1; j < word_length_; j++) {
					int tj = letter_types[j];
					if (tj == U_LTR || tj == U_EURO_NUM) {
						last_good = j;
					}
					else if (tj == U_COMMON_NUM_SEP || tj == U_OTHER_NEUTRAL) {
						// do nothing.
					}
					else {
						break;
					}
				}
				// [i..last_good] is the L sequence
				for (int k = i; k <= last_good; k++) letter_types[k] = U_LTR;
				i = last_good + 1;
			}
			else {
				letter_types[i] = U_RTL;
				i++;
			}
		}

		// At this point, letter_types is entirely U_LTR or U_RTL.
		for (int i = word_length_ - 1; i >= 0;) {
			if (letter_types[i] == U_RTL) {
				blob_indices->push_back(i);
				i--;
			}
			else {
				// left to right sequence.  scan to the beginning.
				int j = i - 1;
				for (; j >= 0 && letter_types[j] != U_RTL; j--) {}  // pass
				// Now (j, i] is LTR
				for (int k = j + 1; k <= i; k++) blob_indices->push_back(k);
				i = j;
			}
		}
		ASSERT_HOST(blob_indices->size() == word_length_);
	}

	static void PrintScriptDirs(const GenericVector<StrongScriptDirection> &dirs) {
		for (int i = 0; i < dirs.size(); i++) {
			switch (dirs[i]) {
			case DIR_NEUTRAL: tprintf("N "); break;
			case DIR_LEFT_TO_RIGHT: tprintf("L "); break;
			case DIR_RIGHT_TO_LEFT: tprintf("R "); break;
			case DIR_MIX: tprintf("Z "); break;
			default: tprintf("? "); break;
			}
		}
		tprintf("\n");
	}

	void ResultIterator::CalculateTextlineOrder(
		bool paragraph_is_ltr,
		const LTRResultIterator &resit,
		GenericVectorEqEq<int> *word_indices) const {
		GenericVector<StrongScriptDirection> directions;
		CalculateTextlineOrder(paragraph_is_ltr, resit, &directions, word_indices);
	}

	void ResultIterator::CalculateTextlineOrder(
		bool paragraph_is_ltr,
		const LTRResultIterator &resit,
		GenericVector<StrongScriptDirection> *dirs_arg,
		GenericVectorEqEq<int> *word_indices) const {
		GenericVector<StrongScriptDirection> dirs;
		GenericVector<StrongScriptDirection> *directions;
		directions = (dirs_arg != NULL) ? dirs_arg : &dirs;
		directions->truncate(0);

		// A LTRResultIterator goes strictly left-to-right word order.
		LTRResultIterator ltr_it(resit);
		ltr_it.RestartRow();
		if (ltr_it.Empty(RIL_WORD)) return;
		do {
			directions->push_back(ltr_it.WordDirection());
		} while (ltr_it.Next(RIL_WORD) && !ltr_it.IsAtBeginningOf(RIL_TEXTLINE));

		word_indices->truncate(0);
		CalculateTextlineOrder(paragraph_is_ltr, *directions, word_indices);
	}

	void ResultIterator::CalculateTextlineOrder(
		bool paragraph_is_ltr,
		const GenericVector<StrongScriptDirection> &word_dirs,
		GenericVectorEqEq<int> *reading_order) {
		reading_order->truncate(0);
		if (word_dirs.size() == 0) return;

		// Take all of the runs of minor direction words and insert them
		// in reverse order.
		int minor_direction, major_direction, major_step, start, end;
		if (paragraph_is_ltr) {
			start = 0;
			end = word_dirs.size();
			major_step = 1;
			major_direction = DIR_LEFT_TO_RIGHT;
			minor_direction = DIR_RIGHT_TO_LEFT;
		}
		else {
			start = word_dirs.size() - 1;
			end = -1;
			major_step = -1;
			major_direction = DIR_RIGHT_TO_LEFT;
			minor_direction = DIR_LEFT_TO_RIGHT;
			// Special rule: if there are neutral words at the right most side
			//   of a line adjacent to a left-to-right word in the middle of the
			//   line, we interpret the end of the line as a single LTR sequence.
			if (word_dirs[start] == DIR_NEUTRAL) {
				int neutral_end = start;
				while (neutral_end > 0 && word_dirs[neutral_end] == DIR_NEUTRAL) {
					neutral_end--;
				}
				if (neutral_end >= 0 && word_dirs[neutral_end] == DIR_LEFT_TO_RIGHT) {
					// LTR followed by neutrals.
					// Scan for the beginning of the minor left-to-right run.
					int left = neutral_end;
					for (int i = left; i >= 0 && word_dirs[i] != DIR_RIGHT_TO_LEFT; i--) {
						if (word_dirs[i] == DIR_LEFT_TO_RIGHT) left = i;
					}
					reading_order->push_back(kMinorRunStart);
					for (int i = left; i < word_dirs.size(); i++) {
						reading_order->push_back(i);
						if (word_dirs[i] == DIR_MIX) reading_order->push_back(kComplexWord);
					}
					reading_order->push_back(kMinorRunEnd);
					start = left - 1;
				}
			}
		}
		for (int i = start; i != end;) {
			if (word_dirs[i] == minor_direction) {
				int j = i;
				while (j != end && word_dirs[j] != major_direction)
					j += major_step;
				if (j == end) j -= major_step;
				while (j != i && word_dirs[j] != minor_direction)
					j -= major_step;
				//  [j..i] is a minor direction run.
				reading_order->push_back(kMinorRunStart);
				for (int k = j; k != i; k -= major_step) {
					reading_order->push_back(k);
				}
				reading_order->push_back(i);
				reading_order->push_back(kMinorRunEnd);
				i = j + major_step;
			}
			else {
				reading_order->push_back(i);
				if (word_dirs[i] == DIR_MIX) reading_order->push_back(kComplexWord);
				i += major_step;
			}
		}
	}

	int ResultIterator::LTRWordIndex() const {
		int this_word_index = 0;
		LTRResultIterator textline(*this);
		textline.RestartRow();
		while (!textline.PositionedAtSameWord(it_)) {
			this_word_index++;
			textline.Next(RIL_WORD);
		}
		return this_word_index;
	}

	void ResultIterator::MoveToLogicalStartOfWord() {
		if (word_length_ == 0) {
			BeginWord(0);
			return;
		}
		GenericVector<int> blob_order;
		CalculateBlobOrder(&blob_order);
		if (blob_order.size() == 0 || blob_order[0] == 0) return;
		BeginWord(blob_order[0]);
	}

	bool ResultIterator::IsAtFinalSymbolOfWord() const {
		if (!it_->word()) return true;
		GenericVector<int> blob_order;
		CalculateBlobOrder(&blob_order);
		return blob_order.size() == 0 || blob_order.back() == blob_index_;
	}

	bool ResultIterator::IsAtFirstSymbolOfWord() const {
		if (!it_->word()) return true;
		GenericVector<int> blob_order;
		CalculateBlobOrder(&blob_order);
		return blob_order.size() == 0 || blob_order[0] == blob_index_;
	}

	void ResultIterator::AppendSuffixMarks(STRING *text) const {
		if (!it_->word()) return;
		bool reading_direction_is_ltr =
			current_paragraph_is_ltr_ ^ in_minor_direction_;
		// scan forward to see what meta-information the word ordering algorithm
		// left us.
		// If this word is at the  *end* of a minor run, insert the other
		// direction's mark;  else if this was a complex word, insert the
		// current reading order's mark.
		GenericVectorEqEq<int> textline_order;
		CalculateTextlineOrder(current_paragraph_is_ltr_,
			*this, &textline_order);
		int this_word_index = LTRWordIndex();
		int i = textline_order.get_index(this_word_index);
		if (i < 0) return;

		int last_non_word_mark = 0;
		for (i++; i < textline_order.size() && textline_order[i] < 0; i++) {
			last_non_word_mark = textline_order[i];
		}
		if (last_non_word_mark == kComplexWord) {
			*text += reading_direction_is_ltr ? kLRM : kRLM;
		}
		else if (last_non_word_mark == kMinorRunEnd) {
			if (current_paragraph_is_ltr_) {
				*text += kLRM;
			}
			else {
				*text += kRLM;
			}
		}
	}

	void ResultIterator::MoveToLogicalStartOfTextline() {
		GenericVectorEqEq<int> word_indices;
		RestartRow();
		CalculateTextlineOrder(current_paragraph_is_ltr_,
			dynamic_cast<const LTRResultIterator&>(*this),
			&word_indices);
		int i = 0;
		for (; i < word_indices.size() && word_indices[i] < 0; i++) {
			if (word_indices[i] == kMinorRunStart) in_minor_direction_ = true;
			else if (word_indices[i] == kMinorRunEnd) in_minor_direction_ = false;
		}
		if (in_minor_direction_) at_beginning_of_minor_run_ = true;
		if (i >= word_indices.size()) return;
		int first_word_index = word_indices[i];
		for (int j = 0; j < first_word_index; j++) {
			PageIterator::Next(RIL_WORD);
		}
		MoveToLogicalStartOfWord();
	}

	void ResultIterator::Begin() {
		LTRResultIterator::Begin();
		current_paragraph_is_ltr_ = CurrentParagraphIsLtr();
		in_minor_direction_ = false;
		at_beginning_of_minor_run_ = false;
		MoveToLogicalStartOfTextline();
	}

	bool ResultIterator::Next(PageIteratorLevel level) {
		if (it_->block() == NULL) return false; // already at end!
		switch (level) {
		case RIL_BLOCK:  // explicit fall-through
		case RIL_PARA:   // explicit fall-through
		case RIL_TEXTLINE:
			if (!PageIterator::Next(level)) return false;
			if (IsWithinFirstTextlineOfParagraph()) {
				// if we've advanced to a new paragraph,
				// recalculate current_paragraph_is_ltr_
				current_paragraph_is_ltr_ = CurrentParagraphIsLtr();
			}
			in_minor_direction_ = false;
			MoveToLogicalStartOfTextline();
			return it_->block() != NULL;
		case RIL_SYMBOL:
		{
			GenericVector<int> blob_order;
			CalculateBlobOrder(&blob_order);
			int next_blob = 0;
			while (next_blob < blob_order.size() &&
				blob_index_ != blob_order[next_blob])
				next_blob++;
			next_blob++;
			if (next_blob < blob_order.size()) {
				// we're in the same word; simply advance one blob.
				BeginWord(blob_order[next_blob]);
				at_beginning_of_minor_run_ = false;
				return true;
			}
			level = RIL_WORD;  // we've fallen through to the next word.
		}
		case RIL_WORD:  // explicit fall-through.
		{
			if (it_->word() == NULL) return Next(RIL_BLOCK);
			GenericVectorEqEq<int> word_indices;
			int this_word_index = LTRWordIndex();
			CalculateTextlineOrder(current_paragraph_is_ltr_,
				*this,
				&word_indices);
			int final_real_index = word_indices.size() - 1;
			while (final_real_index > 0 && word_indices[final_real_index] < 0)
				final_real_index--;
			for (int i = 0; i < final_real_index; i++) {
				if (word_indices[i] == this_word_index) {
					int j = i + 1;
					for (; j < final_real_index && word_indices[j] < 0; j++) {
						if (word_indices[j] == kMinorRunStart) in_minor_direction_ = true;
						if (word_indices[j] == kMinorRunEnd) in_minor_direction_ = false;
					}
					at_beginning_of_minor_run_ = (word_indices[j - 1] == kMinorRunStart);
					// awesome, we move to word_indices[j]
					if (BidiDebug(3)) {
						tprintf("Next(RIL_WORD): %d -> %d\n",
							this_word_index, word_indices[j]);
					}
					PageIterator::RestartRow();
					for (int k = 0; k < word_indices[j]; k++) {
						PageIterator::Next(RIL_WORD);
					}
					MoveToLogicalStartOfWord();
					return true;
				}
			}
			if (BidiDebug(3)) {
				tprintf("Next(RIL_WORD): %d -> EOL\n", this_word_index);
			}
			// we're going off the end of the text line.
			return Next(RIL_TEXTLINE);
		}
		}
		ASSERT_HOST(false);  // shouldn't happen.
		return false;
	}

	bool ResultIterator::IsAtBeginningOf(PageIteratorLevel level) const {
		if (it_->block() == NULL) return false;  // Already at the end!
		if (it_->word() == NULL) return true;  // In an image block.
		if (level == RIL_SYMBOL) return true;  // Always at beginning of a symbol.

		bool at_word_start = IsAtFirstSymbolOfWord();
		if (level == RIL_WORD) return at_word_start;

		ResultIterator line_start(*this);
		// move to the first word in the line...
		line_start.MoveToLogicalStartOfTextline();

		bool at_textline_start = at_word_start && *line_start.it_ == *it_;
		if (level == RIL_TEXTLINE) return at_textline_start;

		// now we move to the left-most word...
		line_start.RestartRow();
		bool at_block_start = at_textline_start &&
			line_start.it_->block() != line_start.it_->prev_block();
		if (level == RIL_BLOCK) return at_block_start;

		bool at_para_start = at_block_start ||
			(at_textline_start &&
				line_start.it_->row()->row->para() !=
				line_start.it_->prev_row()->row->para());
		if (level == RIL_PARA) return at_para_start;

		ASSERT_HOST(false);  // shouldn't happen.
		return false;
	}

	/**
	 * NOTE! This is an exact copy of PageIterator::IsAtFinalElement with the
	 *   change that the variable next is now a ResultIterator instead of a
	 *   PageIterator.
	 */
	bool ResultIterator::IsAtFinalElement(PageIteratorLevel level,
		PageIteratorLevel element) const {
		if (Empty(element)) return true;  // Already at the end!
		// The result is true if we step forward by element and find we are
		// at the the end of the page or at beginning of *all* levels in:
		// [level, element).
		// When there is more than one level difference between element and level,
		// we could for instance move forward one symbol and still be at the first
		// word on a line, so we also have to be at the first symbol in a word.
		ResultIterator next(*this);
		next.Next(element);
		if (next.Empty(element)) return true;  // Reached the end of the page.
		while (element > level) {
			element = static_cast<PageIteratorLevel>(element - 1);
			if (!next.IsAtBeginningOf(element))
				return false;
		}
		return true;
	}

	/**
	 * Returns the null terminated UTF-8 encoded text string for the current
	 * object at the given level. Use delete [] to free after use.
	 */
	char* ResultIterator::GetUTF8Text(PageIteratorLevel level) const {
		if (it_->word() == NULL) return NULL;  // Already at the end!
		STRING text;
		switch (level) {
		case RIL_BLOCK:
		{
			ResultIterator pp(*this);
			do {
				pp.AppendUTF8ParagraphText(&text);
			} while (pp.Next(RIL_PARA) && pp.it_->block() == it_->block());
		}
		break;
		case RIL_PARA:
			AppendUTF8ParagraphText(&text);
			break;
		case RIL_TEXTLINE:
		{
			ResultIterator it(*this);
			it.MoveToLogicalStartOfTextline();
			it.IterateAndAppendUTF8TextlineText(&text);
		}
		break;
		case RIL_WORD:
			AppendUTF8WordText(&text);
			break;
		case RIL_SYMBOL:
		{
			bool reading_direction_is_ltr =
				current_paragraph_is_ltr_ ^ in_minor_direction_;
			if (at_beginning_of_minor_run_) {
				text += reading_direction_is_ltr ? kLRM : kRLM;
			}
			text = it_->word()->BestUTF8(blob_index_, !reading_direction_is_ltr);
			if (IsAtFinalSymbolOfWord()) AppendSuffixMarks(&text);
		}
		break;
		}
		int length = text.length() + 1;
		char* result = new char[length];
		strncpy(result, text.string(), length);
		return result;
	}

	void ResultIterator::AppendUTF8WordText(STRING *text) const {
		if (!it_->word()) return;
		ASSERT_HOST(it_->word()->best_choice != NULL);
		bool reading_direction_is_ltr =
			current_paragraph_is_ltr_ ^ in_minor_direction_;
		if (at_beginning_of_minor_run_) {
			*text += reading_direction_is_ltr ? kLRM : kRLM;
		}

		GenericVector<int> blob_order;
		CalculateBlobOrder(&blob_order);
		for (int i = 0; i < blob_order.size(); i++) {
			*text += it_->word()->BestUTF8(blob_order[i], !reading_direction_is_ltr);
		}
		AppendSuffixMarks(text);
	}

	void ResultIterator::IterateAndAppendUTF8TextlineText(STRING *text) {
		if (Empty(RIL_WORD)) {
			Next(RIL_WORD);
			return;
		}
		if (BidiDebug(1)) {
			GenericVectorEqEq<int> textline_order;
			GenericVector<StrongScriptDirection> dirs;
			CalculateTextlineOrder(current_paragraph_is_ltr_,
				*this, &dirs, &textline_order);
			tprintf("Strong Script dirs     [%p/P=%s]: ", it_->row(),
				current_paragraph_is_ltr_ ? "ltr" : "rtl");
			PrintScriptDirs(dirs);
			tprintf("Logical textline order [%p/P=%s]: ", it_->row(),
				current_paragraph_is_ltr_ ? "ltr" : "rtl");
			for (int i = 0; i < textline_order.size(); i++) {
				tprintf("%d ", textline_order[i]);
			}
			tprintf("\n");
		}

		int words_appended = 0;
		do {
			int numSpaces = preserve_interword_spaces_ ? it_->word()->word->space()
				: (words_appended > 0);
			for (int i = 0; i < numSpaces; ++i) {
				*text += " ";
			}
			AppendUTF8WordText(text);
			words_appended++;
		} while (Next(RIL_WORD) && !IsAtBeginningOf(RIL_TEXTLINE));
		if (BidiDebug(1)) {
			tprintf("%d words printed\n", words_appended);
		}
		*text += line_separator_;
		// If we just finished a paragraph, add an extra newline.
		if (it_->block() == NULL || IsAtBeginningOf(RIL_PARA))
			*text += paragraph_separator_;
	}

	void ResultIterator::AppendUTF8ParagraphText(STRING *text) const {
		ResultIterator it(*this);
		it.RestartParagraph();
		it.MoveToLogicalStartOfTextline();
		if (it.Empty(RIL_WORD)) return;
		do {
			it.IterateAndAppendUTF8TextlineText(text);
		} while (it.it_->block() != NULL && !it.IsAtBeginningOf(RIL_PARA));
	}

	bool ResultIterator::BidiDebug(int min_level) const {
		int debug_level = 1;
		IntParam *p = ParamUtils::FindParam<IntParam>(
			"bidi_debug", GlobalParams()->int_params,
			tesseract_->params()->int_params);
		if (p != NULL) debug_level = (inT32)(*p);
		return debug_level >= min_level;
	}

}  // namespace tesseract.