dfa_decode.c

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/*
 * Copyright (c) 1991-2006 Kawahara Lab., Kyoto University
 * Copyright (c) 2000-2005 Shikano Lab., Nara Institute of Science and Technology
 * Copyright (c) 2005-2006 Julius project team, Nagoya Institute of Technology, Nagoya Institute of Technology
 * All rights reserved
 */

#include <julius.h>
#ifdef USE_DFA

int
dfa_firstwords(NEXTWORD **nw, int peseqlen, int maxnw, DFA_INFO *dfa)
{
  DFA_ARC *arc;
  MULTIGRAM *m;
  int s, sb, se;
  int cate, iw, ns;
  int num = 0;

  for (m = gramlist; m; m = m->next) {
    if (m->active) {
      sb = m->state_begin;
      se = sb + m->dfa->state_num;
      for(s=sb;s<se;s++) {
        if ((dfa->st[s].status & INITIAL_S) != 0) { /* from initial state */
          for (arc = dfa->st[s].arc; arc; arc = arc->next) {    /* for all arc */
            cate = arc->label;  /* category ID */
            ns = arc->to_state; /* next DFA state ID */
            /* all words within the category is expanded */
            for (iw=0;iw<dfa->term.wnum[cate];iw++) {
              nw[num]->id = dfa->term.tw[cate][iw]; /* word ID */
              nw[num]->next_state = ns; /* next state */
              nw[num]->can_insert_sp = FALSE; /* short pause should not inserted before this word */
              num++;
              if (num >= maxnw) return -1; /* buffer overflow */
            }
          }
        }
      }
    }
  }

  return num;
}

int
dfa_nextwords(NODE *hypo, NEXTWORD **nw, int maxnw, DFA_INFO *dfa)
{
  DFA_ARC *arc, *arc2;
  int iw,cate,ns,cate2,ns2;
  int num = 0;

  /* hypo->state: current DFA state ID */
  for (arc = dfa->st[hypo->state].arc; arc; arc = arc->next) {/* for all arc */
    cate = arc->label;
    ns = arc->to_state;
    if (dfa->is_sp[cate]) {     /* short pause */
      /* expand one more next (not expand the short pause word itself) */
      for (arc2 = dfa->st[ns].arc; arc2; arc2 = arc2->next) {
        cate2 = arc2->label;
        ns2 = arc2->to_state;
        for (iw=0;iw<dfa->term.wnum[cate2];iw++) {
          nw[num]->id = dfa->term.tw[cate2][iw];
          nw[num]->next_state = ns2;
          nw[num]->can_insert_sp = TRUE;
          num++;
          if (num >= maxnw) return -1; /* buffer overflow */
        }
      }
    } else {                    /* not short pause */
      /* all words within the category is expanded */
      for (iw=0;iw<dfa->term.wnum[cate];iw++) {
        nw[num]->id = dfa->term.tw[cate][iw];
        nw[num]->next_state = ns;
        nw[num]->can_insert_sp = FALSE;
        num++;
        if (num >= maxnw) return -1; /* buffer overflow */
      }
    }
  }
  return num;
}


boolean
dfa_acceptable(NODE *hypo, DFA_INFO *dfa)
{
  if (dfa->st[hypo->state].status & ACCEPT_S) {
    return TRUE;
  } else {
    return FALSE;
  }
}

/* patch by kashima */
boolean
dfa_look_around(NEXTWORD *nword, NODE *hypo, BACKTRELLIS *bt)
{
  int t,tm;
  int i;
  WORD_ID w;
  
  tm = hypo->estimated_next_t;  /* estimated connection time */

  /* look aound [tm-lookup_range..tm+lookup_range] frame */
  /* near the center is better:
     1. the first half (backward)   2. the second half (forward) */
  /* 1. backward */
  for(t = tm; t >= tm - lookup_range; t--) {
    if (t < 0) break;
     for (i=0;i<bt->num[t];i++) {
       w = (bt->rw[t][i])->wid;
       if(w == nword->id){      /* found */
         nword->tre = bt->rw[t][i];
         return TRUE;
       }
     }
  }
  /* 2. forward */
  for(t = tm + 1; t < tm + lookup_range; t++) {
    if (t > bt->framelen - 1) break;
    if (t >= hypo->bestt) break;
    for (i=0;i<bt->num[t];i++) {
      w = (bt->rw[t][i])->wid;
      if(w == nword->id){       /* found */
        nword->tre = bt->rw[t][i];
        return TRUE;
      }
    }
  }

  return FALSE;                 /* not found */
}

#endif /* USE_DFA */

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