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https://github.com/tesseract-ocr/tesseract.git
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f382fb56f5
git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@106 d0cd1f9f-072b-0410-8dd7-cf729c803f20
520 lines
16 KiB
C++
520 lines
16 KiB
C++
/* -*-C-*-
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********************************************************************************
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*
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* File: bestfirst.c (Formerly bestfirst.c)
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* Description: Best first search functions
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* Author: Mark Seaman, OCR Technology
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* Created: Mon May 14 11:23:29 1990
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* Modified: Tue Jul 30 16:08:47 1991 (Mark Seaman) marks@hpgrlt
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* Language: C
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* Package: N/A
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* Status: Experimental (Do Not Distribute)
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*
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* (c) Copyright 1990, 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 "bestfirst.h"
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#include "heuristic.h"
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#include "plotseg.h"
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#include "tordvars.h"
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#include "debug.h"
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#include "pieces.h"
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#include "stopper.h"
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#include "metrics.h"
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#include "states.h"
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#include "bitvec.h"
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#include "freelist.h"
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#include "permute.h"
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#include "structures.h"
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#include "wordclass.h"
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void call_caller();
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/*----------------------------------------------------------------------
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V a r i a b l e s
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---------------------------------------------------------------------*/
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int num_joints; /* Number of chunks - 1 */
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int num_pushed = 0;
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int num_popped = 0;
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make_int_var (num_seg_states, 30, make_seg_states,
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9, 1, set_seg_states, "Segmentation states");
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make_float_var (worst_state, 1, make_worst_state,
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9, 9, set_worst_state, "Worst segmentation state");
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/**/
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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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/**********************************************************************
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* init_bestfirst_vars
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*
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* Create and initialize references to debug variables that control
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* operations in this file.
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**********************************************************************/
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void init_bestfirst_vars() {
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make_seg_states();
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make_worst_state();
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}
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/**********************************************************************
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* best_first_search
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*
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* Find the best segmentation by doing a best first search of the
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* solution space.
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**********************************************************************/
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void best_first_search(CHUNKS_RECORD *chunks_record,
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A_CHOICE *best_choice,
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A_CHOICE *raw_choice,
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STATE *state,
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DANGERR *fixpt,
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STATE *best_state,
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INT32 pass) {
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SEARCH_RECORD *the_search;
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INT16 keep_going;
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STATE guided_state;
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num_joints = matrix_dimension (chunks_record->ratings) - 1;
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the_search = new_search (chunks_record, num_joints,
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best_choice, raw_choice, state);
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#ifndef GRAPHICS_DISABLED
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save_best_state(chunks_record);
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#endif
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start_recording();
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FLOAT32 worst_priority = 2.0f * prioritize_state(chunks_record,
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the_search,
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best_state);
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if (worst_priority < worst_state)
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worst_priority = worst_state;
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guided_state = *state;
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do {
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/* Look for answer */
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if (!hash_lookup (the_search->closed_states, the_search->this_state)) {
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if (blob_skip) {
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free_state (the_search->this_state);
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break;
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}
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guided_state = *(the_search->this_state);
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keep_going =
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evaluate_state(chunks_record, the_search, fixpt, best_state, pass);
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hash_add (the_search->closed_states, the_search->this_state);
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if (!keep_going ||
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(the_search->num_states > num_seg_states) || (blob_skip)) {
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free_state (the_search->this_state);
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break;
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}
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expand_node(worst_priority, chunks_record, the_search);
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}
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free_state (the_search->this_state);
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num_popped++;
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the_search->this_state = pop_queue (the_search->open_states);
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}
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while (the_search->this_state);
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state->part1 = the_search->best_state->part1;
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state->part2 = the_search->best_state->part2;
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stop_recording();
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delete_search(the_search);
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}
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/**********************************************************************
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* chunks_width
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*
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* Return the width of several of the chunks (if they were joined to-
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* gether.
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**********************************************************************/
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int chunks_width(WIDTH_RECORD *width_record, int start_chunk, int last_chunk) {
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int result = 0;
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int x;
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for (x = start_chunk * 2; x <= last_chunk * 2; x++)
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result += width_record->widths[x];
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return (result);
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}
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/**********************************************************************
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* delete_search
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*
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* Terminate the current search and free all the memory involved.
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**********************************************************************/
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void delete_search(SEARCH_RECORD *the_search) {
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float closeness;
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closeness = (the_search->num_joints ?
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(hamming_distance ((unsigned long *) the_search->first_state,
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(unsigned long *) the_search->best_state,
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2) / (float) the_search->num_joints) : 0.0);
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record_search_status (the_search->num_states,
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the_search->before_best, closeness);
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free_state (the_search->first_state);
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free_state (the_search->best_state);
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free_hash_table (the_search->closed_states);
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FreeHeapData (the_search->open_states, (void_dest) free_state);
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memfree(the_search);
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}
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/**********************************************************************
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* evaluate_chunks
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*
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* A particular word level segmentation has been chosen. Evaluation
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* this to find the word list that corresponds to it.
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**********************************************************************/
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CHOICES_LIST evaluate_chunks(CHUNKS_RECORD *chunks_record,
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SEARCH_STATE search_state,
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STATE *this_state,
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STATE *best_state,
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INT32 pass) {
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CHOICES_LIST char_choices;
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CHOICES this_choice;
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int i;
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int x = 0;
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int y;
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char_choices = new_choice_list ();
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/* Iterate sub-paths */
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for (i = 1; i <= search_state[0] + 1; i++) {
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if (i > search_state[0])
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y = count_blobs (chunks_record->chunks) - 1;
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else
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y = x + search_state[i];
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if (blob_skip) {
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array_free(char_choices);
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return (NULL);
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} /* Process one square */
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/* Classify if needed */
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this_choice = get_piece_rating (chunks_record->ratings,
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chunks_record->chunks,
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chunks_record->splits,
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x, y,
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chunks_record->fx,
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this_state, best_state, pass, i - 1);
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if (this_choice == NIL) {
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array_free(char_choices);
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return (NULL);
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}
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/* Add permuted ratings */
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last_segmentation[i - 1].certainty = best_certainty (this_choice);
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last_segmentation[i - 1].match = best_probability (this_choice);
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last_segmentation[i - 1].width =
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chunks_width (chunks_record->chunk_widths, x, y);
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last_segmentation[i - 1].gap =
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chunks_gap (chunks_record->chunk_widths, y);
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char_choices = array_push (char_choices, this_choice);
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x = y + 1;
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}
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return (char_choices);
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}
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/**********************************************************************
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* evaluate_state
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*
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* Evaluate the segmentation that is represented by this state in the
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* best first search. Add this state to the "states_seen" list.
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**********************************************************************/
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INT16 evaluate_state(CHUNKS_RECORD *chunks_record,
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SEARCH_RECORD *the_search,
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DANGERR *fixpt,
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STATE *best_state,
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INT32 pass) {
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CHOICES_LIST char_choices;
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SEARCH_STATE chunk_groups;
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float rating_limit = class_probability (the_search->best_choice);
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INT16 keep_going = TRUE;
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PIECES_STATE widths;
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the_search->num_states++;
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chunk_groups = bin_to_chunks (the_search->this_state,
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the_search->num_joints);
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bin_to_pieces (the_search->this_state, the_search->num_joints, widths);
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LogNewSegmentation(widths);
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rating_limit = class_probability (the_search->best_choice);
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char_choices =
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evaluate_chunks (chunks_record, chunk_groups, the_search->this_state,
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best_state, pass);
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if (char_choices != NULL) {
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permute_characters (char_choices,
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rating_limit,
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the_search->best_choice, the_search->raw_choice);
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if (AcceptableChoice (char_choices, the_search->best_choice,
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the_search->raw_choice, fixpt))
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keep_going = FALSE;
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array_free(char_choices);
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}
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#ifndef GRAPHICS_DISABLED
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if (display_segmentations) {
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display_segmentation (chunks_record->chunks, chunk_groups);
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if (display_segmentations > 1)
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window_wait(segm_window);
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}
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#endif
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if (rating_limit != class_probability (the_search->best_choice)) {
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the_search->before_best = the_search->num_states;
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the_search->best_state->part1 = the_search->this_state->part1;
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the_search->best_state->part2 = the_search->this_state->part2;
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replace_char_widths(chunks_record, chunk_groups);
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}
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else if (char_choices != NULL)
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fixpt->index = -1;
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memfree(chunk_groups);
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return (keep_going);
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}
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/**********************************************************************
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* rebuild_current_state
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*
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* Evaluate the segmentation that is represented by this state in the
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* best first search. Add this state to the "states_seen" list.
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**********************************************************************/
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CHOICES_LIST rebuild_current_state(TBLOB *blobs,
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SEAMS seam_list,
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STATE *state,
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CHOICES_LIST old_choices,
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int fx) {
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CHOICES_LIST char_choices;
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SEARCH_STATE search_state;
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int i;
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int num_joints = array_count (seam_list);
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int x = 0;
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int blobindex; /*current blob */
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TBLOB *p_blob;
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TBLOB *blob;
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TBLOB *next_blob;
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int y;
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search_state = bin_to_chunks (state, num_joints);
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char_choices = new_choice_list ();
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/* Iterate sub-paths */
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for (i = 1; i <= search_state[0]; i++) {
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y = x + search_state[i];
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x = y + 1;
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char_choices = array_push (char_choices, NULL);
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}
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char_choices = array_push (char_choices, NULL);
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y = count_blobs (blobs) - 1;
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for (i = search_state[0]; i >= 0; i--) {
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if (x == y) { /*single fragment */
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array_value (char_choices, i) = array_value (old_choices, x);
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/*grab the list */
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array_value (old_choices, x) = NULL;
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}
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else {
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join_pieces(blobs, seam_list, x, y);
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for (blob = blobs, blobindex = 0, p_blob = NULL; blobindex < x;
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blobindex++) {
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p_blob = blob;
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blob = blob->next;
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}
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while (blobindex < y) {
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next_blob = blob->next;
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blob->next = next_blob->next;
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oldblob(next_blob); /*junk dead blobs */
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blobindex++;
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}
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array_value (char_choices, i) =
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(char *) classify_blob (p_blob, blob, blob->next, NULL, fx,
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"rebuild", Orange, NULL, NULL, 0, 0);
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}
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y = x - 1;
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x = y - search_state[i];
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}
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memfree(search_state);
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free_all_choices(old_choices, x);
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return (char_choices);
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}
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/**********************************************************************
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* expand_node
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*
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* Create the states that are attached to this one. Check to see that
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* each one has not already been visited. If not add it to the priority
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* queue.
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**********************************************************************/
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void expand_node(FLOAT32 worst_priority,
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CHUNKS_RECORD *chunks_record, SEARCH_RECORD *the_search) {
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STATE old_state;
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int x;
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int mask = 1 << (the_search->num_joints - 1 - 32);
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old_state.part1 = the_search->this_state->part1;
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old_state.part2 = the_search->this_state->part2;
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for (x = the_search->num_joints; x > 32; x--) {
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the_search->this_state->part1 = mask ^ old_state.part1;
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if (!hash_lookup (the_search->closed_states, the_search->this_state))
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push_queue (the_search->open_states, the_search->this_state,
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worst_priority,
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prioritize_state (chunks_record, the_search, &old_state));
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mask >>= 1;
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}
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if (the_search->num_joints > 32) {
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mask = 1 << 31;
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}
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else {
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mask = 1 << (the_search->num_joints - 1);
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}
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while (x--) {
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the_search->this_state->part2 = mask ^ old_state.part2;
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if (!hash_lookup (the_search->closed_states, the_search->this_state))
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push_queue (the_search->open_states, the_search->this_state,
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worst_priority,
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prioritize_state (chunks_record, the_search, &old_state));
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mask >>= 1;
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}
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}
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/**********************************************************************
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* new_search
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*
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* Create and initialize a new search record.
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**********************************************************************/
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SEARCH_RECORD *new_search(CHUNKS_RECORD *chunks_record,
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int num_joints,
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A_CHOICE *best_choice,
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A_CHOICE *raw_choice,
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STATE *state) {
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SEARCH_RECORD *this_search;
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this_search = (SEARCH_RECORD *) memalloc (sizeof (SEARCH_RECORD));
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this_search->open_states = MakeHeap (num_seg_states * 20);
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this_search->closed_states = new_hash_table ();
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if (state)
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this_search->this_state = new_state (state);
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else
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cprintf ("error: bad initial state in new_search\n");
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this_search->first_state = new_state (this_search->this_state);
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this_search->best_state = new_state (this_search->this_state);
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this_search->best_choice = best_choice;
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this_search->raw_choice = raw_choice;
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this_search->num_joints = num_joints;
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this_search->num_states = 0;
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this_search->before_best = 0;
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return (this_search);
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}
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/**********************************************************************
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* pop_queue
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*
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* Get this state from the priority queue. It should be the state that
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* has the greatest urgency to be evaluated.
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**********************************************************************/
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STATE *pop_queue(HEAP *queue) {
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HEAPENTRY entry;
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if (GetTopOfHeap (queue, &entry) == OK) {
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#ifndef GRAPHICS_DISABLED
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if (display_segmentations) {
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cprintf ("eval state: %8.3f ", entry.Key);
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print_state ("", (STATE *) entry.Data, num_joints);
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}
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#endif
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return ((STATE *) entry.Data);
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}
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else {
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return (NULL);
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}
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}
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/**********************************************************************
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* push_queue
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*
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* Add this state into the priority queue.
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**********************************************************************/
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void push_queue(HEAP *queue, STATE *state, FLOAT32 worst_priority,
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FLOAT32 priority) {
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HEAPENTRY entry;
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if (SizeOfHeap (queue) < MaxSizeOfHeap (queue) && priority < worst_priority) {
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entry.Data = (char *) new_state (state);
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num_pushed++;
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entry.Key = priority;
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HeapStore(queue, &entry);
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}
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}
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/**********************************************************************
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* replace_char_widths
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*
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* Replace the value of the char_width field in the chunks_record with
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* the updated width measurements from the last_segmentation.
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**********************************************************************/
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void replace_char_widths(CHUNKS_RECORD *chunks_record, SEARCH_STATE state) {
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WIDTH_RECORD *width_record;
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int num_blobs;
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int i;
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free_widths (chunks_record->char_widths);
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num_blobs = state[0] + 1;
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width_record = (WIDTH_RECORD *) memalloc (sizeof (int) * num_blobs * 2);
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width_record->num_chars = num_blobs;
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for (i = 0; i < num_blobs; i++) {
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width_record->widths[2 * i] = last_segmentation[i].width;
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if (i + 1 < num_blobs)
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width_record->widths[2 * i + 1] = last_segmentation[i].gap;
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}
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chunks_record->char_widths = width_record;
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}
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