/* $XConsortium: jdlossy.c,v 1.4 94/04/17 20:35:35 rws Exp $ */
/* Module jdlossy.c */

/****************************************************************************

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				NOTICE
                              
This software is being provided by AGE Logic, Inc. under the
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*****************************************************************************

	jdlossy.c - decode JPEG images,  Lossy method

	this contain code for:

	1) JPEG Lossless, grayscale
	2) JPEG Lossless, color

	Ben Fahy, AGE Logic, Oct 1993
	Gary Rogers, AGE Logic, Inc., January 1994

****************************************************************************/

#include "jpeg.h"

/**********************************************************************/
decode_jpeg_lossy_gray(state)
JpegDecodeState *state;
{
	return( decode_jpeg_lossy_color(state) );
}
/**********************************************************************/
decode_jpeg_lossy_color(state)
JpegDecodeState *state;
{
int status;

/*  our output buffer is guaranteed to be clean on entry.   */
/*  (every time we write data below, we return to flush it) */
    state->nl_found=0;
    state->nl_flushed=0;

    while(1) {		/* loop forever (we're a state machine) */

	switch( state->goal) {
	case JPEG_DECODE_GOAL_Startup:
	   state->goal = JPEG_DECODE_GOAL_ReadDataForInit;

	case JPEG_DECODE_GOAL_ReadDataForInit:
	   /* we start up by reading data into our buffer and calling INIT */
	   status = fill_jpeg_decode_buffer(state);
	   switch(status) {
	    case JPEG_BUFFER_LastBuffer:
		break;

	    case JPEG_BUFFER_BufferFilled:
		/* all is coolness */
		break;

	    case JPEG_BUFFER_NeedAnotherStrip:
		state->needs_input_strip = 1;
		return(state->nl_found);
		break;

	    case JPEG_BUFFER_BufferError:
	    default: 
  	      	state->error_code = JPEG_DECODE_ERROR_CouldNotStart;
	   	return(-1);
	   }

	   /* if here, we should have a nice full input buffer */

	case JPEG_DECODE_GOAL_TryToInit:
	   status = JD_INIT(state->cinfo,
			    state->dc_methods,
			    state->e_methods,
			    state->up_sample);
	   if (status == XIE_ERR) {
  	        state->error_code = JPEG_DECODE_ERROR_CouldNotInit;
		return(-1);
	   }
	   if (status == XIE_NRML) {
		state->goal = JPEG_DECODE_GOAL_InitDone;
		break;
	   } 
	   if (status == XIE_INP) {
		state->goal = JPEG_DECODE_GOAL_ReadDataForInit;
		break;
	   }
	   /* hey! we aren't supposed to be here */
	   state->error_code = JPEG_DECODE_ERROR_BadInitRetCode;
	   return(-1);
	   break;

	case JPEG_DECODE_GOAL_InitDone:

	   /* now we know enough to allocate our output buffer */
	   state->cinfo->output_workspace =
		alloc_sampimage(state->cinfo,
			(int) state->cinfo->comps_in_scan,
			(long) state->cinfo->rows_in_mem,
			state->cinfo->image_width
		);
	   if (state->cinfo->output_workspace == NULL) {
  	       state->error_code = JPEG_DECODE_ERROR_BadOutputAlloc;
	       return(-1);
	   }
	   state->goal = JPEG_DECODE_GOAL_ProcessData;

	case JPEG_DECODE_GOAL_ProcessData:
	   status = JD_PROCESS(state->cinfo);

	   if (status == XIE_INP) {
		state->goal = JPEG_DECODE_GOAL_ReadDataForProcess;
		break;
	   }
	   if (status == XIE_OUT) {
		state->goal = JPEG_DECODE_GOAL_WriteDataForProcess;
		break;
	   }
	   if (status == XIE_EOI) {
		state->goal = JPEG_DECODE_GOAL_EndOfInput;
		break;
	   }
	   if (status == XIE_NRML) 
		break;

	   if (status == XIE_ERR) {
  	       state->error_code = JPEG_DECODE_ERROR_DecodeError;
	       return(-1);
	   }
	   else {
		/* unexpected return status */
  	        state->error_code = JPEG_DECODE_ERROR_DecoderIsFreakingOut;
	        return(-1);
	   }
	   break;

	case JPEG_DECODE_GOAL_ReadDataForProcess:
	   status = fill_jpeg_decode_buffer(state);
	   switch(status) {
	    case JPEG_BUFFER_LastBuffer:
		break;

	    case JPEG_BUFFER_BufferFilled:
		/* all is coolness */
		break;

	    case JPEG_BUFFER_NeedAnotherStrip:
		state->needs_input_strip = 1;
		return(state->nl_found);
		break;

	    case JPEG_BUFFER_BufferError:
	    default: 
  	      	state->error_code = JPEG_DECODE_ERROR_NoMoreProcessData;
	   	return(-1);
	   }
	   state->goal = JPEG_DECODE_GOAL_ProcessData;
	   break;

	case JPEG_DECODE_GOAL_EndOfInput:
	   state->goal = JPEG_DECODE_GOAL_Done;
	   state->nl_found = (state->cinfo->image_height - 
			      state->cinfo->pixel_rows_output);
	      /* see jdXIE_get() if this seems *too* self-serving */

		/* leave for good */
	   return(state->nl_found);
	   break;

	case JPEG_DECODE_GOAL_WriteDataForProcess:
	   state->goal = JPEG_DECODE_GOAL_ProcessData;
	   state->cinfo->pixel_rows_output += state->cinfo->rows_in_mem;
	   state->nl_found = state->cinfo->rows_in_mem;
		/* leave to flush data */
	   return(state->nl_found);
	   break;

	default:
  	   state->error_code = JPEG_DECODE_ERROR_BadGoal;
	   return(-1);
	}
    }
}
/**********************************************************************/
