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97d47a406d
All of them were found by codespell. Signed-off-by: Stefan Weil <sw@weilnetz.de>
400 lines
15 KiB
C++
400 lines
15 KiB
C++
/* -*-C-*-
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********************************************************************************
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*
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* File: permdawg.c (Formerly permdawg.c)
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* Description: Scale word choices by a dictionary
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* Author: Mark Seaman, OCR Technology
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* Created: Fri Oct 16 14:37:00 1987
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* Modified: Tue Jul 9 15:43:18 1991 (Mark Seaman) marks@hpgrlt
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* Language: C
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* Package: N/A
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* Status: Reusable Software Component
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*
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* (c) Copyright 1987, Hewlett-Packard Company.
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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** http://www.apache.org/licenses/LICENSE-2.0
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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*
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*********************************************************************************/
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/*----------------------------------------------------------------------
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I n c l u d e s
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----------------------------------------------------------------------*/
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#include "cutil.h"
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#include "dawg.h"
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#include "freelist.h"
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#include "globals.h"
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#include "ndminx.h"
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#include "stopper.h"
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#include "tprintf.h"
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#include "params.h"
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#include <ctype.h>
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#include "dict.h"
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/*----------------------------------------------------------------------
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F u n c t i o n s
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----------------------------------------------------------------------*/
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namespace tesseract {
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/**
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* @name go_deeper_dawg_fxn
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*
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* If the choice being composed so far could be a dictionary word
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* keep exploring choices.
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*/
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void Dict::go_deeper_dawg_fxn(
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const char *debug, const BLOB_CHOICE_LIST_VECTOR &char_choices,
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int char_choice_index, const CHAR_FRAGMENT_INFO *prev_char_frag_info,
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bool word_ending, WERD_CHOICE *word, float certainties[], float *limit,
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WERD_CHOICE *best_choice, int *attempts_left, void *void_more_args) {
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DawgArgs *more_args = reinterpret_cast<DawgArgs*>(void_more_args);
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word_ending = (char_choice_index == char_choices.size()-1);
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int word_index = word->length() - 1;
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if (best_choice->rating() < *limit) return;
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// Look up char in DAWG
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// If the current unichar is an ngram first try calling
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// letter_is_okay() for each unigram it contains separately.
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UNICHAR_ID orig_uch_id = word->unichar_id(word_index);
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bool checked_unigrams = false;
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if (getUnicharset().get_isngram(orig_uch_id)) {
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if (dawg_debug_level) {
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tprintf("checking unigrams in an ngram %s\n",
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getUnicharset().debug_str(orig_uch_id).string());
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}
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int num_unigrams = 0;
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word->remove_last_unichar_id();
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GenericVector<UNICHAR_ID> encoding;
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const char *ngram_str = getUnicharset().id_to_unichar(orig_uch_id);
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// Since the string came out of the unicharset, failure is impossible.
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ASSERT_HOST(getUnicharset().encode_string(ngram_str, true, &encoding, NULL,
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NULL));
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bool unigrams_ok = true;
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// Construct DawgArgs that reflect the current state.
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DawgPositionVector unigram_active_dawgs = *(more_args->active_dawgs);
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DawgPositionVector unigram_updated_dawgs;
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DawgArgs unigram_dawg_args(&unigram_active_dawgs,
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&unigram_updated_dawgs,
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more_args->permuter);
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// Check unigrams in the ngram with letter_is_okay().
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for (int i = 0; unigrams_ok && i < encoding.size(); ++i) {
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UNICHAR_ID uch_id = encoding[i];
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ASSERT_HOST(uch_id != INVALID_UNICHAR_ID);
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++num_unigrams;
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word->append_unichar_id(uch_id, 1, 0.0, 0.0);
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unigrams_ok = (this->*letter_is_okay_)(
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&unigram_dawg_args,
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word->unichar_id(word_index+num_unigrams-1),
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word_ending && i == encoding.size() - 1);
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(*unigram_dawg_args.active_dawgs) = *(unigram_dawg_args.updated_dawgs);
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if (dawg_debug_level) {
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tprintf("unigram %s is %s\n",
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getUnicharset().debug_str(uch_id).string(),
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unigrams_ok ? "OK" : "not OK");
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}
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}
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// Restore the word and copy the updated dawg state if needed.
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while (num_unigrams-- > 0) word->remove_last_unichar_id();
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word->append_unichar_id_space_allocated(orig_uch_id, 1, 0.0, 0.0);
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if (unigrams_ok) {
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checked_unigrams = true;
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more_args->permuter = unigram_dawg_args.permuter;
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*(more_args->updated_dawgs) = *(unigram_dawg_args.updated_dawgs);
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}
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}
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// Check which dawgs from the dawgs_ vector contain the word
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// up to and including the current unichar.
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if (checked_unigrams || (this->*letter_is_okay_)(
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more_args, word->unichar_id(word_index), word_ending)) {
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// Add a new word choice
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if (word_ending) {
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if (dawg_debug_level) {
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tprintf("found word = %s\n", word->debug_string().string());
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}
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if (strcmp(output_ambig_words_file.string(), "") != 0) {
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if (output_ambig_words_file_ == NULL) {
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output_ambig_words_file_ =
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fopen(output_ambig_words_file.string(), "wb+");
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if (output_ambig_words_file_ == NULL) {
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tprintf("Failed to open output_ambig_words_file %s\n",
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output_ambig_words_file.string());
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exit(1);
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}
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STRING word_str;
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word->string_and_lengths(&word_str, NULL);
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word_str += " ";
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fprintf(output_ambig_words_file_, "%s", word_str.string());
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}
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STRING word_str;
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word->string_and_lengths(&word_str, NULL);
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word_str += " ";
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fprintf(output_ambig_words_file_, "%s", word_str.string());
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}
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WERD_CHOICE *adjusted_word = word;
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adjusted_word->set_permuter(more_args->permuter);
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update_best_choice(*adjusted_word, best_choice);
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} else { // search the next letter
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// Make updated_* point to the next entries in the DawgPositionVector
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// arrays (that were originally created in dawg_permute_and_select)
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++(more_args->updated_dawgs);
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// Make active_dawgs and constraints point to the updated ones.
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++(more_args->active_dawgs);
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permute_choices(debug, char_choices, char_choice_index + 1,
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prev_char_frag_info, word, certainties, limit,
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best_choice, attempts_left, more_args);
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// Restore previous state to explore another letter in this position.
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--(more_args->updated_dawgs);
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--(more_args->active_dawgs);
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}
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} else {
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if (dawg_debug_level) {
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tprintf("last unichar not OK at index %d in %s\n",
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word_index, word->debug_string().string());
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}
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}
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}
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/**
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* dawg_permute_and_select
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*
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* Recursively explore all the possible character combinations in
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* the given char_choices. Use go_deeper_dawg_fxn() to search all the
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* dawgs in the dawgs_ vector in parallel and discard invalid words.
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*
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* Allocate and return a WERD_CHOICE with the best valid word found.
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*/
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WERD_CHOICE *Dict::dawg_permute_and_select(
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const BLOB_CHOICE_LIST_VECTOR &char_choices, float rating_limit) {
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WERD_CHOICE *best_choice = new WERD_CHOICE(&getUnicharset());
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best_choice->make_bad();
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best_choice->set_rating(rating_limit);
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if (char_choices.length() == 0 || char_choices.length() > MAX_WERD_LENGTH)
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return best_choice;
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DawgPositionVector *active_dawgs =
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new DawgPositionVector[char_choices.length() + 1];
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init_active_dawgs(&(active_dawgs[0]), true);
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DawgArgs dawg_args(&(active_dawgs[0]), &(active_dawgs[1]), NO_PERM);
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WERD_CHOICE word(&getUnicharset(), MAX_WERD_LENGTH);
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float certainties[MAX_WERD_LENGTH];
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this->go_deeper_fxn_ = &tesseract::Dict::go_deeper_dawg_fxn;
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int attempts_left = max_permuter_attempts;
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permute_choices((dawg_debug_level) ? "permute_dawg_debug" : NULL,
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char_choices, 0, NULL, &word, certainties, &rating_limit, best_choice,
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&attempts_left, &dawg_args);
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delete[] active_dawgs;
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return best_choice;
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}
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/**
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* permute_choices
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*
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* Call append_choices() for each BLOB_CHOICE in BLOB_CHOICE_LIST
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* with the given char_choice_index in char_choices.
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*/
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void Dict::permute_choices(
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const char *debug,
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const BLOB_CHOICE_LIST_VECTOR &char_choices,
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int char_choice_index,
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const CHAR_FRAGMENT_INFO *prev_char_frag_info,
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WERD_CHOICE *word,
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float certainties[],
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float *limit,
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WERD_CHOICE *best_choice,
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int *attempts_left,
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void *more_args) {
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if (debug) {
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tprintf("%s permute_choices: char_choice_index=%d"
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" limit=%g rating=%g, certainty=%g word=%s\n",
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debug, char_choice_index, *limit, word->rating(),
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word->certainty(), word->debug_string().string());
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}
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if (char_choice_index < char_choices.length()) {
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BLOB_CHOICE_IT blob_choice_it;
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blob_choice_it.set_to_list(char_choices.get(char_choice_index));
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for (blob_choice_it.mark_cycle_pt(); !blob_choice_it.cycled_list();
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blob_choice_it.forward()) {
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(*attempts_left)--;
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append_choices(debug, char_choices, *(blob_choice_it.data()),
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char_choice_index, prev_char_frag_info, word,
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certainties, limit, best_choice, attempts_left, more_args);
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if (*attempts_left <= 0) {
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if (debug) tprintf("permute_choices(): attempts_left is 0\n");
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break;
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}
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}
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}
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}
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/**
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* append_choices
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*
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* Checks to see whether or not the next choice is worth appending to
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* the word being generated. If so then keeps going deeper into the word.
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*
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* This function assumes that Dict::go_deeper_fxn_ is set.
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*/
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void Dict::append_choices(
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const char *debug,
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const BLOB_CHOICE_LIST_VECTOR &char_choices,
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const BLOB_CHOICE &blob_choice,
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int char_choice_index,
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const CHAR_FRAGMENT_INFO *prev_char_frag_info,
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WERD_CHOICE *word,
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float certainties[],
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float *limit,
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WERD_CHOICE *best_choice,
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int *attempts_left,
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void *more_args) {
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int word_ending =
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(char_choice_index == char_choices.length() - 1) ? true : false;
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// Deal with fragments.
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CHAR_FRAGMENT_INFO char_frag_info;
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if (!fragment_state_okay(blob_choice.unichar_id(), blob_choice.rating(),
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blob_choice.certainty(), prev_char_frag_info, debug,
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word_ending, &char_frag_info)) {
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return; // blob_choice must be an invalid fragment
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}
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// Search the next letter if this character is a fragment.
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if (char_frag_info.unichar_id == INVALID_UNICHAR_ID) {
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permute_choices(debug, char_choices, char_choice_index + 1,
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&char_frag_info, word, certainties, limit,
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best_choice, attempts_left, more_args);
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return;
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}
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// Add the next unichar.
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float old_rating = word->rating();
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float old_certainty = word->certainty();
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uinT8 old_permuter = word->permuter();
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certainties[word->length()] = char_frag_info.certainty;
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word->append_unichar_id_space_allocated(
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char_frag_info.unichar_id, char_frag_info.num_fragments,
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char_frag_info.rating, char_frag_info.certainty);
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// Explore the next unichar.
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(this->*go_deeper_fxn_)(debug, char_choices, char_choice_index,
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&char_frag_info, word_ending, word, certainties,
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limit, best_choice, attempts_left, more_args);
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// Remove the unichar we added to explore other choices in it's place.
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word->remove_last_unichar_id();
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word->set_rating(old_rating);
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word->set_certainty(old_certainty);
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word->set_permuter(old_permuter);
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}
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/**
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* @name fragment_state
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*
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* Given the current char choice and information about previously seen
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* fragments, determines whether adjacent character fragments are
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* present and whether they can be concatenated.
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*
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* The given prev_char_frag_info contains:
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* - fragment: if not NULL contains information about immediately
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* preceding fragmented character choice
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* - num_fragments: number of fragments that have been used so far
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* to construct a character
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* - certainty: certainty of the current choice or minimum
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* certainty of all fragments concatenated so far
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* - rating: rating of the current choice or sum of fragment
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* ratings concatenated so far
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*
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* The output char_frag_info is filled in as follows:
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* - character: is set to be NULL if the choice is a non-matching
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* or non-ending fragment piece; is set to unichar of the given choice
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* if it represents a regular character or a matching ending fragment
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* - fragment,num_fragments,certainty,rating are set as described above
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*
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* @returns false if a non-matching fragment is discovered, true otherwise.
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*/
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bool Dict::fragment_state_okay(UNICHAR_ID curr_unichar_id,
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float curr_rating, float curr_certainty,
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const CHAR_FRAGMENT_INFO *prev_char_frag_info,
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const char *debug, int word_ending,
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CHAR_FRAGMENT_INFO *char_frag_info) {
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const CHAR_FRAGMENT *this_fragment =
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getUnicharset().get_fragment(curr_unichar_id);
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const CHAR_FRAGMENT *prev_fragment =
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prev_char_frag_info != NULL ? prev_char_frag_info->fragment : NULL;
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// Print debug info for fragments.
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if (debug && (prev_fragment || this_fragment)) {
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tprintf("%s check fragments: choice=%s word_ending=%d\n", debug,
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getUnicharset().debug_str(curr_unichar_id).string(),
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word_ending);
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if (prev_fragment) {
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tprintf("prev_fragment %s\n", prev_fragment->to_string().string());
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}
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if (this_fragment) {
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tprintf("this_fragment %s\n", this_fragment->to_string().string());
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}
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}
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char_frag_info->unichar_id = curr_unichar_id;
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char_frag_info->fragment = this_fragment;
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char_frag_info->rating = curr_rating;
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char_frag_info->certainty = curr_certainty;
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char_frag_info->num_fragments = 1;
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if (prev_fragment && !this_fragment) {
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if (debug) tprintf("Skip choice with incomplete fragment\n");
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return false;
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}
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if (this_fragment) {
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// We are dealing with a fragment.
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char_frag_info->unichar_id = INVALID_UNICHAR_ID;
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if (prev_fragment) {
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if (!this_fragment->is_continuation_of(prev_fragment)) {
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if (debug) tprintf("Non-matching fragment piece\n");
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return false;
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}
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if (this_fragment->is_ending()) {
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char_frag_info->unichar_id =
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getUnicharset().unichar_to_id(this_fragment->get_unichar());
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char_frag_info->fragment = NULL;
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if (debug) {
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tprintf("Built character %s from fragments\n",
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getUnicharset().debug_str(
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char_frag_info->unichar_id).string());
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}
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} else {
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if (debug) tprintf("Record fragment continuation\n");
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char_frag_info->fragment = this_fragment;
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}
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// Update certainty and rating.
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char_frag_info->rating =
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prev_char_frag_info->rating + curr_rating;
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char_frag_info->num_fragments = prev_char_frag_info->num_fragments + 1;
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char_frag_info->certainty =
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MIN(curr_certainty, prev_char_frag_info->certainty);
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} else {
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if (this_fragment->is_beginning()) {
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if (debug) tprintf("Record fragment beginning\n");
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} else {
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if (debug) {
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tprintf("Non-starting fragment piece with no prev_fragment\n");
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}
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return false;
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}
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}
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}
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if (word_ending && char_frag_info->fragment) {
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if (debug) tprintf("Word can not end with a fragment\n");
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return false;
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}
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return true;
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}
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} // namespace tesseract
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