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git-svn-id: https://tesseract-ocr.googlecode.com/svn/trunk@1044 d0cd1f9f-072b-0410-8dd7-cf729c803f20
90 lines
3.5 KiB
C++
90 lines
3.5 KiB
C++
/**********************************************************************
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* File: word_list_lang_model.h
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* Description: Declaration of the Word List Language Model Class
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* Author: Ahmad Abdulkader
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* Created: 2008
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*
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* (C) Copyright 2008, Google Inc.
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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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// The WordListLangModel class abstracts a language model that is based on
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// a list of words. It inherits from the LangModel abstract class
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// Besides providing the methods inherited from the LangModel abstract class,
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// the class provided methods to add new strings to the Language Model:
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// AddString & AddString32
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#ifndef WORD_LIST_LANG_MODEL_H
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#define WORD_LIST_LANG_MODEL_H
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#include <vector>
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#include "cube_reco_context.h"
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#include "lang_model.h"
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#include "tess_lang_mod_edge.h"
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namespace tesseract {
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class Trie;
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class WordListLangModel : public LangModel {
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public:
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explicit WordListLangModel(CubeRecoContext *cntxt);
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~WordListLangModel();
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// Returns an edge pointer to the Root
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LangModEdge *Root();
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// Returns the edges that fan-out of the specified edge and their count
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LangModEdge **GetEdges(CharAltList *alt_list,
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LangModEdge *edge,
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int *edge_cnt);
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// Returns is a sequence of 32-bit characters are valid within this language
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// model or net. And EndOfWord flag is specified. If true, the sequence has
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// to end on a valid word. The function also optionally returns the list
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// of language model edges traversed to parse the string
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bool IsValidSequence(const char_32 *sequence,
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bool eow_flag,
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LangModEdge **edges);
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bool IsLeadingPunc(char_32 ch) { return false; } // not yet implemented
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bool IsTrailingPunc(char_32 ch) { return false; } // not yet implemented
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bool IsDigit(char_32 ch) { return false; } // not yet implemented
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// Adds a new UTF-8 string to the language model
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bool AddString(const char *char_ptr);
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// Adds a new UTF-32 string to the language model
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bool AddString32(const char_32 *char_32_ptr);
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// Compute all the variants of a 32-bit string in terms of the class-ids.
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// This is needed for languages that have ligatures. A word can then have
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// more than one spelling in terms of the class-ids.
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static void WordVariants(const CharSet &char_set, const UNICHARSET *uchset,
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string_32 str32,
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vector<WERD_CHOICE *> *word_variants);
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private:
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// constants needed to configure the language model
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static const int kMaxEdge = 512;
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CubeRecoContext *cntxt_;
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Trie *dawg_;
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bool init_;
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// Initialize the language model
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bool Init();
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// Cleanup
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void Cleanup();
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// Recursive helper function for WordVariants().
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static void WordVariants(
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const CharSet &char_set,
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string_32 prefix_str32, WERD_CHOICE *word_so_far,
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string_32 str32,
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vector<WERD_CHOICE *> *word_variants);
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};
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} // tesseract
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#endif // WORD_LIST_LANG_MODEL_H
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