tomwalters@0: /*
tomwalters@0:     Copyright (c) Applied Psychology Unit, Medical Research Council. 1988, 1989
tomwalters@0:     ===========================================================================
tomwalters@0: 
tomwalters@0:     Permission to use, copy, modify, and distribute this software without fee 
tomwalters@0:     is hereby granted for research purposes, provided that this copyright 
tomwalters@0:     notice appears in all copies and in all supporting documentation, and that 
tomwalters@0:     the software is not redistributed for any fee (except for a nominal shipping 
tomwalters@0:     charge). Anyone wanting to incorporate all or part of this software in a
tomwalters@0:     commercial product must obtain a license from the Medical Research Council.
tomwalters@0: 
tomwalters@0:     The MRC makes no representations about the suitability of this 
tomwalters@0:     software for any purpose.  It is provided "as is" without express or implied 
tomwalters@0:     warranty.
tomwalters@0:  
tomwalters@0:     THE MRC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING 
tomwalters@0:     ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL THE
tomwalters@0:     A.P.U. BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY 
tomwalters@0:     DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN 
tomwalters@0:     AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 
tomwalters@0:     OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
tomwalters@0: */
tomwalters@0: 
tomwalters@0: /*
tomwalters@0: 	phase.c
tomwalters@0: 	=======
tomwalters@0: 
tomwalters@0:     looks after phase compensation of all filter types
tomwalters@0: 
tomwalters@0: 
tomwalters@0: */
tomwalters@0: 
tomwalters@0: #include "stitch.h"
tomwalters@0: #include "phase.h"
tomwalters@0: 
tomwalters@0: 
tomwalters@0: PhaseCompensatorState *NewPhaseCompensator( filter_state, filter_module, sample_delay )
tomwalters@0: FilterState  filter_state ;
tomwalters@0: FilterModule filter_module ;
tomwalters@0: double       sample_delay ;
tomwalters@0: {
tomwalters@0:     DeclareNew( PhaseCompensatorState *, compensator_state ) ;
tomwalters@0: 
tomwalters@0:     compensator_state->filter_state  = filter_state  ;
tomwalters@0:     compensator_state->filter_module = filter_module ;
tomwalters@0:     compensator_state->sample_delay  = sample_delay + 0.5 ;
tomwalters@0: 
tomwalters@0:     compensator_state->delay_buffer  = ( Pointer ) 0 ;
tomwalters@0: 
tomwalters@0:     return( compensator_state ) ;
tomwalters@0: }
tomwalters@0: 
tomwalters@0: PointCount PhaseCompensateFilter( compensator_state, input, output, points )
tomwalters@0: PhaseCompensatorState *compensator_state ;
tomwalters@0: Pointer input ;
tomwalters@0: Pointer output ;
tomwalters@0: PointCount points ;
tomwalters@0: {
tomwalters@0:     unsigned output_size ;
tomwalters@0:     int byte_delay, bytes ;
tomwalters@0:     PointCount process ;
tomwalters@0:     Pointer input_ptr ;
tomwalters@0:     static int zero = 0 ;
tomwalters@0: 
tomwalters@0:     /* support for new and old zero point transfers to get any remaining
tomwalters@0: 	data from filters - in short a mess */
tomwalters@0: 
tomwalters@0:     if( compensator_state->sample_delay < 0 && ( input == ( Pointer ) 0 || points == 0 ) ) {
tomwalters@0: 	process = - ( int ) compensator_state->sample_delay ;
tomwalters@0: 
tomwalters@0: 	if( process > points && points != 0 )
tomwalters@0: 	    process = points ;
tomwalters@0: 
tomwalters@0: 	compensator_state->sample_delay = ( int ) compensator_state->sample_delay + process ;
tomwalters@0: 
tomwalters@0: 	input_ptr = ( Pointer ) 0 ;
tomwalters@0:     }
tomwalters@0:     else {
tomwalters@0: 	process = points ;
tomwalters@0: 	input_ptr = input ;
tomwalters@0:     }
tomwalters@0: 
tomwalters@0:     /* call filter pod */
tomwalters@0: 
tomwalters@0:     output_size = compensator_state->filter_module(
tomwalters@0: 		      &compensator_state->filter_state,
tomwalters@0: 		      &zero,
tomwalters@0: 		      input_ptr,
tomwalters@0: 		      output,
tomwalters@0: 		      process,
tomwalters@0: 		      1
tomwalters@0: 		  ) ;
tomwalters@0: 
tomwalters@0:     byte_delay = ( int ) compensator_state->sample_delay * output_size ;
tomwalters@0:     bytes = points * output_size ;
tomwalters@0: 
tomwalters@0:     if( compensator_state->delay_buffer == ( Pointer ) 0 )
tomwalters@0: 	if( ( int ) compensator_state->sample_delay < 0 ) {
tomwalters@0: 	    stitch_bcopy( output - byte_delay, output, bytes - byte_delay ) ;
tomwalters@0: 	    compensator_state->delay_buffer   = ( Pointer ) 0 + 1 ;
tomwalters@0: 
tomwalters@0: 	    return( points + ( int ) compensator_state->sample_delay ) ;
tomwalters@0: 	}
tomwalters@0: 	else
tomwalters@0: 	    compensator_state->delay_buffer = stitch_calloc(
tomwalters@0: 				 ( unsigned ) compensator_state->sample_delay * 2,
tomwalters@0: 					      output_size, "phase.c for delay buffer\n" ) ;
tomwalters@0: 
tomwalters@0:     if( byte_delay > bytes ) {
tomwalters@0: 	stitch_bcopy( output, compensator_state->delay_buffer + byte_delay, bytes ) ;
tomwalters@0: 	stitch_bcopy( compensator_state->delay_buffer, output, bytes ) ;
tomwalters@0: 	stitch_bcopy( compensator_state->delay_buffer + bytes, compensator_state->delay_buffer, byte_delay ) ;
tomwalters@0:     }
tomwalters@0:     else if( byte_delay > 0 ) {
tomwalters@0: 	stitch_bcopy( output + bytes - byte_delay, compensator_state->delay_buffer + byte_delay, byte_delay ) ;
tomwalters@0: 	stitch_bcopy( output, output + byte_delay,  bytes - byte_delay ) ;
tomwalters@0: 	stitch_bcopy( compensator_state->delay_buffer, output, byte_delay ) ;
tomwalters@0: 	stitch_bcopy( compensator_state->delay_buffer + byte_delay, compensator_state->delay_buffer, byte_delay ) ;
tomwalters@0:     }
tomwalters@0: 
tomwalters@0:     return( process ) ;
tomwalters@0: }
tomwalters@0: 
tomwalters@0: void FreeCompensatedFilter( compensator_state )
tomwalters@0: PhaseCompensatorState *compensator_state ;
tomwalters@0: {
tomwalters@0:     stitch_free( compensator_state->filter_state ) ;
tomwalters@0:     stitch_free( ( Pointer ) compensator_state ) ;
tomwalters@0: 
tomwalters@0:     return ;
tomwalters@0: }
tomwalters@0: