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+/* 
+ *  libpinyin
+ *  Library to deal with pinyin.
+ *  
+ *  Copyright (C) 2012 Peng Wu <alexepico@gmail.com>
+ *  
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ * 
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *  GNU General Public License for more details.
+ *  
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+
+#ifndef PINYIN_LOOKUP2_H
+#define PINYIN_LOOKUP2_H
+
+
+#include <float.h>
+#include <glib.h>
+#include "novel_types.h"
+#include "chewing_key.h"
+#include "phrase_index.h"
+#include "ngram.h"
+#include "lookup.h"
+
+
+namespace pinyin{
+
+/**
+ * pinyin_lookup2.h
+ *
+ * The definitions of pinyin lookup related classes and structs.
+ *
+ */
+
+
+
+enum constraint_type{NO_CONSTRAINT, CONSTRAINT_ONESTEP, CONSTRAINT_NOSEARCH };
+
+struct lookup_constraint_t{
+    /* current type of the step */
+    constraint_type m_type;
+
+    /* Note:
+     *   value of m_type:
+     *     NO_CONSTRAINT:
+     *       no values in the below union.
+     *       search all possible next words.
+     *     CONSTRAINT_ONESTEP:
+     *       m_token contains the next word.
+     *       only one word can be used to search for the next step,
+     *       use case for user selected candidates.
+     *     CONSTRAINT_NOSEARCH:
+     *       m_constraint_step contains the value
+     *       which points back to the CONSTRAINT_ONESTEP step.
+     *       no search is allowed for the current step.
+     */
+
+    union{
+	phrase_token_t m_token;
+	guint32 m_constraint_step; /* index of m_token */
+    };
+};
+
+
+/**
+ * PinyinLookup2:
+ *
+ * The pinyin lookup class to convert pinyin keys to guessed sentence.
+ *
+ */
+class PinyinLookup2{
+private:
+    static const gfloat bigram_lambda;
+    static const gfloat unigram_lambda;
+
+    PhraseItem m_cache_phrase_item;
+    SingleGram m_merged_single_gram;
+
+protected:
+    /* saved varibles */
+    CandidateConstraints m_constraints;
+    ChewingKeyVector m_keys;
+
+    pinyin_option_t m_options;
+    FacadeChewingTable * m_pinyin_table;
+    FacadePhraseIndex * m_phrase_index;
+    Bigram * m_system_bigram;
+    Bigram * m_user_bigram;
+
+    /* internal step data structure */
+    GPtrArray * m_steps_index;
+    /* Array of LookupStepIndex */
+    GPtrArray * m_steps_content;
+    /* Array of LookupStepContent */
+
+
+    bool search_unigram2(GPtrArray * topresults, int nstep, int npinyin,
+                         PhraseIndexRanges ranges);
+    bool search_bigram2(GPtrArray * topresults, int nstep, int npinyin,
+                        PhraseIndexRanges ranges);
+
+    bool unigram_gen_next_step(int nstep, lookup_value_t * cur_step, phrase_token_t token);
+    bool bigram_gen_next_step(int nstep, lookup_value_t * cur_step, phrase_token_t token, gfloat bigram_poss);
+
+    bool save_next_step(int next_step_pos, lookup_value_t * cur_step, lookup_value_t * next_step);
+
+    bool final_step(MatchResults & results);
+
+public:
+    /**
+     * PinyinLookup2::PinyinLookup2:
+     * @options: the pinyin options.
+     * @pinyin_table: the pinyin table.
+     * @phrase_index: the phrase index.
+     * @system_bigram: the system bi-gram.
+     * @user_bigram: the user bi-gram.
+     *
+     * The constructor of the PinyinLookup2.
+     *
+     */
+    PinyinLookup2(pinyin_option_t options, FacadeChewingTable * pinyin_table,
+                  FacadePhraseIndex * phrase_index, Bigram * system_bigram,
+                  Bigram * user_bigram);
+
+    /**
+     * PinyinLookup2::~PinyinLookup2:
+     *
+     * The destructor of the PinyinLookup2.
+     *
+     */
+    ~PinyinLookup2();
+
+    /**
+     * PinyinLookup2::set_options:
+     * @options: the pinyin options.
+     * @returns: whether the set operation is successful.
+     *
+     * Set the pinyin options.
+     *
+     */
+    bool set_options(pinyin_option_t options) {
+        m_options = options;
+        return true;
+    }
+
+    /**
+     * PinyinLookup2::get_best_match:
+     * @prefixes: the phrase tokens before the guessed sentence.
+     * @keys: the pinyin keys of the guessed sentence.
+     * @constraints: the constraints on the guessed sentence.
+     * @results: the guessed sentence in the form of the phrase tokens.
+     * @returns: whether the guess operation is successful.
+     *
+     * Guess the best sentence according to user inputs.
+     *
+     */
+    bool get_best_match(TokenVector prefixes, ChewingKeyVector keys, CandidateConstraints constraints, MatchResults & results);
+
+    /**
+     * PinyinLookup2::train_result2:
+     * @keys: the pinyin keys of the guessed sentence.
+     * @constraints: the constraints on the guessed sentence.
+     * @results: the guessed sentence in the form of the phrase tokens.
+     * @returns: whether the train operation is successful.
+     *
+     * Self learning the guessed sentence based on the constraints.
+     *
+     */
+    bool train_result2(ChewingKeyVector keys, CandidateConstraints constraints, MatchResults results);
+
+    /**
+     * PinyinLookup2::convert_to_utf8:
+     * @results: the guessed sentence in the form of the phrase tokens.
+     * @result_string: the guessed sentence in the utf8 encoding.
+     * @returns: whether the convert operation is successful.
+     *
+     * Convert the guessed sentence from the phrase tokens to the utf8 string.
+     *
+     */
+    bool convert_to_utf8(MatchResults results,
+                         /* out */ char * & result_string)
+    {
+        return pinyin::convert_to_utf8(m_phrase_index, results,
+                                       NULL, result_string);
+    }
+
+
+    /**
+     * PinyinLookup2::add_constraint:
+     * @constraints: the constraints on the guessed sentence.
+     * @index: the character offset in the guessed sentence.
+     * @token: the phrase token in the candidate list chosen by user.
+     * @returns: the number of the characters in the chosen token.
+     *
+     * Add one constraint to the constraints on the guessed sentence.
+     *
+     */
+    guint8 add_constraint(CandidateConstraints constraints, size_t index, phrase_token_t token);
+
+    /**
+     * PinyinLookup2::clear_constraint:
+     * @constraints: the constraints on the guessed sentence.
+     * @index: the character offset in the guessed sentence.
+     * @returns: whether the clear operation is successful.
+     *
+     * Clear one constraint in the constraints on the guessed sentence.
+     *
+     */
+    bool clear_constraint(CandidateConstraints constraints, size_t index);
+
+    /**
+     * PinyinLookup2::validate_constraint:
+     * @constraints: the constraints on the guessed sentence.
+     * @keys: the pinyin keys of the guessed sentence.
+     * @returns: whether the validate operation is successful.
+     *
+     * Validate the old constraints with the new pinyin keys.
+     *
+     */
+    bool validate_constraint(CandidateConstraints constraints, ChewingKeyVector keys);
+
+};
+
+};
+
+#endif