wfst_aux.cc

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/*************************************************************************/
/*                                                                       */
/*                Centre for Speech Technology Research                  */
/*                     University of Edinburgh, UK                       */
/*                         Copyright (c) 1997                            */
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/*************************************************************************/
/*                     Author :  Alan W Black                            */
/*                     Date   :  November 1997                           */
/*-----------------------------------------------------------------------*/
/*                                                                       */
/* internal classes, methods and function used in minimization and       */
/* determinization of WFST.                                              */
/*                                                                       */
/*=======================================================================*/
#include <iostream>
#include "EST_WFST.h"
#include "wfst_aux.h"

wfst_marks::wfst_marks(int x)
{
    // Set up mark table
    int i,j;

    // Triangular matrix
    p_x = x;
    p_mark_table = new char *[x];
    for (i=0; i < x; i++)
    {
    p_mark_table[i] = new char[i+1];
    for (j=0; j < i+1; j++)
        p_mark_table[i][j] = '?';
    }
    
}

wfst_marks::~wfst_marks()
{
    int i;

    for (i=0; i < p_x; i++)
    delete [] p_mark_table[i];
    delete [] p_mark_table;
    p_mark_table = 0;
}

void wfst_marks::find_state_map(EST_IVector &state_map,int &num_new_states)
{
    // Find the mapping from old state names to new
    int i,j,new_name;
    
    state_map.resize(p_x);

    for (i=0,new_name=0; i < p_x; i++)
    {
    state_map[i] = -1;
    for (j=0; j < i; j++)
        if (!distinguished(j,i))
        {
        state_map[i] = state_map[j];
        break;
        }
    if (state_map[i] == -1)
        state_map[i] = new_name++;
    }

    num_new_states = new_name;
}

void add_assumption(int y,int z,wfst_assumes &assumptions)
{
    // Add a binding of y to z, and z to y to assumptions
    EST_Litem *p;
    int y_ok = FALSE;
    int z_ok = FALSE;

    for (p=assumptions.list.head(); p != 0; p=p->next())
    {
    if (assumptions.list(p).k == y)
    {
        assumptions.list(p).v.append(z);
        y_ok = TRUE;
    }
    if (assumptions.list(p).k == z)
    {
        assumptions.list(p).v.append(y);
        z_ok = TRUE;
    }
    if (z_ok && y_ok)
        break;
    }
    if (!z_ok)
    {
    EST_IList b;
    b.append(y);
    assumptions.add_item(z,b);
    }
    if (!y_ok)
    {
    EST_IList b;
    b.append(z);
    assumptions.add_item(y,b);
    }
}

int equivalent_to(int y,int z,wfst_assumes &assumptions)
{
    // true if y == z or z is assumed to be equivalent to y
    EST_Litem *p,*q;

    if (y==z)
    return TRUE;
    else 
    {
    for (p=assumptions.list.head(); p != 0; p=p->next())
    {
        if (assumptions.list(p).k == y)
        {
        EST_IList &b = assumptions.list(p).v;
        for (q=b.head(); q != 0; q=q->next())
            if (z == b(q))
            return TRUE;
        }
        if (assumptions.list(p).k == z)
        {   
        EST_IList &b = assumptions.list(p).v;
        for (q=b.head(); q != 0; q=q->next())
            if (y == b(q))
            return TRUE;
        }
    }
    return FALSE;
    }
}

void mark_undistinguished(wfst_marks &marks,wfst_assumes &assumptions)
{
    EST_Litem *p, *q;

    for (p=assumptions.list.head(); p != 0; p=p->next())
    {
    int x = assumptions.list(p).k;
    EST_IList &b = assumptions.list(p).v;
    for (q=b.head(); q != 0; q=q->next())
        marks.undistinguish(x,b(q));
    }
}

VAL_REGISTER_CLASS(wfst,EST_WFST)