/* convolve.h: Header for convolutions.
 *
 *  Copyright (C) 1999 Ralph Loader <suckfish@ihug.co.nz>
 *
 *  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 CONVOLVE_H
#define CONVOLVE_H

#ifdef __cplusplus
extern "C" {
#endif

/* convolve_match takes two blocks, one twice the size of the other.  The
 * sizes of these are CONVOLVE_BIG and CONVOLVE_SMALL respectively. */
#define CONVOLVE_DEPTH 8
#define CONVOLVE_SMALL (1 << CONVOLVE_DEPTH)
#define CONVOLVE_BIG (CONVOLVE_SMALL * 2)

typedef union stack_entry_s
{
	struct {const double * left, * right; double * out;} v;
	struct {double * main, * null;} b;

} stack_entry;

#define STACK_SIZE (CONVOLVE_DEPTH * 3)

typedef struct convolve_state {
	double left [CONVOLVE_BIG];
	double right [CONVOLVE_SMALL * 3];
	double scratch [CONVOLVE_SMALL * 3];
	stack_entry stack[STACK_SIZE];
} convolve_state;


convolve_state *convolve_init (void);
void convolve_close (convolve_state * state);

int convolve_match (float * lastchoice,
		    float * input,
		    convolve_state * state);

#ifdef __cplusplus
}
#endif

#endif