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/*
 * \file ngram_model_arpa.h ARPABO text format for N-Gram models
 *
 * Author: David Huggins-Daines <dhuggins@cs.cmu.edu>
 */

#ifndef __NGRAM_MODEL_ARPA_H__
#define __NGRAM_MODEL_ARPA_H__

#include "ngram_model_internal.h"
#include "lm3g_model.h"

/**
 * Bigram structure.
 */
struct bigram_s {
    uint32 wid;	/**< Index of unigram entry for this.  (NOT dictionary id.) */
    uint16 prob2;	/**< Index into array of actual bigram probs */
    uint16 bo_wt2;	/**< Index into array of actual bigram backoff wts */
    uint16 trigrams;	/**< Index of 1st entry in lm_t.trigrams[],
			     RELATIVE TO its segment base (see above) */
};

/**
 * Trigram structure.
 *
 * As with bigrams, trigram prob info kept in a separate table for conserving
 * memory space.
 */
struct trigram_s {
    uint32 wid;	  /**< Index of unigram entry for this.  (NOT dictionary id.) */
    uint16 prob3; /**< Index into array of actual trigram probs */
};


/**
 * Subclass of ngram_model for ARPA file reading.
 */
typedef struct ngram_model_arpa_s {
    ngram_model_t base;  /**< Base ngram_model_t structure */
    lm3g_model_t lm3g;  /**< Shared lm3g structure */

    /* Arrays of unique bigram probs and bo-wts, and trigram probs
     * (these are temporary, actually) */
    sorted_list_t sorted_prob2;
    sorted_list_t sorted_bo_wt2;
    sorted_list_t sorted_prob3;
} ngram_model_arpa_t;

#endif /* __NGRAM_MODEL_ARPA_H__ */