nuclear@26: /*
nuclear@26:  * jcmainct.c
nuclear@26:  *
nuclear@26:  * Copyright (C) 1994-1996, Thomas G. Lane.
nuclear@26:  * This file is part of the Independent JPEG Group's software.
nuclear@26:  * For conditions of distribution and use, see the accompanying README file.
nuclear@26:  *
nuclear@26:  * This file contains the main buffer controller for compression.
nuclear@26:  * The main buffer lies between the pre-processor and the JPEG
nuclear@26:  * compressor proper; it holds downsampled data in the JPEG colorspace.
nuclear@26:  */
nuclear@26: 
nuclear@26: #define JPEG_INTERNALS
nuclear@26: #include "jinclude.h"
nuclear@26: #include "jpeglib.h"
nuclear@26: 
nuclear@26: 
nuclear@26: /* Note: currently, there is no operating mode in which a full-image buffer
nuclear@26:  * is needed at this step.  If there were, that mode could not be used with
nuclear@26:  * "raw data" input, since this module is bypassed in that case.  However,
nuclear@26:  * we've left the code here for possible use in special applications.
nuclear@26:  */
nuclear@26: #undef FULL_MAIN_BUFFER_SUPPORTED
nuclear@26: 
nuclear@26: 
nuclear@26: /* Private buffer controller object */
nuclear@26: 
nuclear@26: typedef struct {
nuclear@26:   struct jpeg_c_main_controller pub; /* public fields */
nuclear@26: 
nuclear@26:   JDIMENSION cur_iMCU_row;	/* number of current iMCU row */
nuclear@26:   JDIMENSION rowgroup_ctr;	/* counts row groups received in iMCU row */
nuclear@26:   boolean suspended;		/* remember if we suspended output */
nuclear@26:   J_BUF_MODE pass_mode;		/* current operating mode */
nuclear@26: 
nuclear@26:   /* If using just a strip buffer, this points to the entire set of buffers
nuclear@26:    * (we allocate one for each component).  In the full-image case, this
nuclear@26:    * points to the currently accessible strips of the virtual arrays.
nuclear@26:    */
nuclear@26:   JSAMPARRAY buffer[MAX_COMPONENTS];
nuclear@26: 
nuclear@26: #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@26:   /* If using full-image storage, this array holds pointers to virtual-array
nuclear@26:    * control blocks for each component.  Unused if not full-image storage.
nuclear@26:    */
nuclear@26:   jvirt_sarray_ptr whole_image[MAX_COMPONENTS];
nuclear@26: #endif
nuclear@26: } my_main_controller;
nuclear@26: 
nuclear@26: typedef my_main_controller * my_main_ptr;
nuclear@26: 
nuclear@26: 
nuclear@26: /* Forward declarations */
nuclear@26: METHODDEF(void) process_data_simple_main
nuclear@26: 	JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@26: 	     JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
nuclear@26: #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@26: METHODDEF(void) process_data_buffer_main
nuclear@26: 	JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@26: 	     JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
nuclear@26: #endif
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Initialize for a processing pass.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
nuclear@26: {
nuclear@26:   my_main_ptr main = (my_main_ptr) cinfo->main;
nuclear@26: 
nuclear@26:   /* Do nothing in raw-data mode. */
nuclear@26:   if (cinfo->raw_data_in)
nuclear@26:     return;
nuclear@26: 
nuclear@26:   main->cur_iMCU_row = 0;	/* initialize counters */
nuclear@26:   main->rowgroup_ctr = 0;
nuclear@26:   main->suspended = FALSE;
nuclear@26:   main->pass_mode = pass_mode;	/* save mode for use by process_data */
nuclear@26: 
nuclear@26:   switch (pass_mode) {
nuclear@26:   case JBUF_PASS_THRU:
nuclear@26: #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@26:     if (main->whole_image[0] != NULL)
nuclear@26:       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@26: #endif
nuclear@26:     main->pub.process_data = process_data_simple_main;
nuclear@26:     break;
nuclear@26: #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@26:   case JBUF_SAVE_SOURCE:
nuclear@26:   case JBUF_CRANK_DEST:
nuclear@26:   case JBUF_SAVE_AND_PASS:
nuclear@26:     if (main->whole_image[0] == NULL)
nuclear@26:       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@26:     main->pub.process_data = process_data_buffer_main;
nuclear@26:     break;
nuclear@26: #endif
nuclear@26:   default:
nuclear@26:     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@26:     break;
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Process some data.
nuclear@26:  * This routine handles the simple pass-through mode,
nuclear@26:  * where we have only a strip buffer.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: process_data_simple_main (j_compress_ptr cinfo,
nuclear@26: 			  JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
nuclear@26: 			  JDIMENSION in_rows_avail)
nuclear@26: {
nuclear@26:   my_main_ptr main = (my_main_ptr) cinfo->main;
nuclear@26: 
nuclear@26:   while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
nuclear@26:     /* Read input data if we haven't filled the main buffer yet */
nuclear@26:     if (main->rowgroup_ctr < DCTSIZE)
nuclear@26:       (*cinfo->prep->pre_process_data) (cinfo,
nuclear@26: 					input_buf, in_row_ctr, in_rows_avail,
nuclear@26: 					main->buffer, &main->rowgroup_ctr,
nuclear@26: 					(JDIMENSION) DCTSIZE);
nuclear@26: 
nuclear@26:     /* If we don't have a full iMCU row buffered, return to application for
nuclear@26:      * more data.  Note that preprocessor will always pad to fill the iMCU row
nuclear@26:      * at the bottom of the image.
nuclear@26:      */
nuclear@26:     if (main->rowgroup_ctr != DCTSIZE)
nuclear@26:       return;
nuclear@26: 
nuclear@26:     /* Send the completed row to the compressor */
nuclear@26:     if (! (*cinfo->coef->compress_data) (cinfo, main->buffer)) {
nuclear@26:       /* If compressor did not consume the whole row, then we must need to
nuclear@26:        * suspend processing and return to the application.  In this situation
nuclear@26:        * we pretend we didn't yet consume the last input row; otherwise, if
nuclear@26:        * it happened to be the last row of the image, the application would
nuclear@26:        * think we were done.
nuclear@26:        */
nuclear@26:       if (! main->suspended) {
nuclear@26: 	(*in_row_ctr)--;
nuclear@26: 	main->suspended = TRUE;
nuclear@26:       }
nuclear@26:       return;
nuclear@26:     }
nuclear@26:     /* We did finish the row.  Undo our little suspension hack if a previous
nuclear@26:      * call suspended; then mark the main buffer empty.
nuclear@26:      */
nuclear@26:     if (main->suspended) {
nuclear@26:       (*in_row_ctr)++;
nuclear@26:       main->suspended = FALSE;
nuclear@26:     }
nuclear@26:     main->rowgroup_ctr = 0;
nuclear@26:     main->cur_iMCU_row++;
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: 
nuclear@26: #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Process some data.
nuclear@26:  * This routine handles all of the modes that use a full-size buffer.
nuclear@26:  */
nuclear@26: 
nuclear@26: METHODDEF(void)
nuclear@26: process_data_buffer_main (j_compress_ptr cinfo,
nuclear@26: 			  JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
nuclear@26: 			  JDIMENSION in_rows_avail)
nuclear@26: {
nuclear@26:   my_main_ptr main = (my_main_ptr) cinfo->main;
nuclear@26:   int ci;
nuclear@26:   jpeg_component_info *compptr;
nuclear@26:   boolean writing = (main->pass_mode != JBUF_CRANK_DEST);
nuclear@26: 
nuclear@26:   while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
nuclear@26:     /* Realign the virtual buffers if at the start of an iMCU row. */
nuclear@26:     if (main->rowgroup_ctr == 0) {
nuclear@26:       for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@26: 	   ci++, compptr++) {
nuclear@26: 	main->buffer[ci] = (*cinfo->mem->access_virt_sarray)
nuclear@26: 	  ((j_common_ptr) cinfo, main->whole_image[ci],
nuclear@26: 	   main->cur_iMCU_row * (compptr->v_samp_factor * DCTSIZE),
nuclear@26: 	   (JDIMENSION) (compptr->v_samp_factor * DCTSIZE), writing);
nuclear@26:       }
nuclear@26:       /* In a read pass, pretend we just read some source data. */
nuclear@26:       if (! writing) {
nuclear@26: 	*in_row_ctr += cinfo->max_v_samp_factor * DCTSIZE;
nuclear@26: 	main->rowgroup_ctr = DCTSIZE;
nuclear@26:       }
nuclear@26:     }
nuclear@26: 
nuclear@26:     /* If a write pass, read input data until the current iMCU row is full. */
nuclear@26:     /* Note: preprocessor will pad if necessary to fill the last iMCU row. */
nuclear@26:     if (writing) {
nuclear@26:       (*cinfo->prep->pre_process_data) (cinfo,
nuclear@26: 					input_buf, in_row_ctr, in_rows_avail,
nuclear@26: 					main->buffer, &main->rowgroup_ctr,
nuclear@26: 					(JDIMENSION) DCTSIZE);
nuclear@26:       /* Return to application if we need more data to fill the iMCU row. */
nuclear@26:       if (main->rowgroup_ctr < DCTSIZE)
nuclear@26: 	return;
nuclear@26:     }
nuclear@26: 
nuclear@26:     /* Emit data, unless this is a sink-only pass. */
nuclear@26:     if (main->pass_mode != JBUF_SAVE_SOURCE) {
nuclear@26:       if (! (*cinfo->coef->compress_data) (cinfo, main->buffer)) {
nuclear@26: 	/* If compressor did not consume the whole row, then we must need to
nuclear@26: 	 * suspend processing and return to the application.  In this situation
nuclear@26: 	 * we pretend we didn't yet consume the last input row; otherwise, if
nuclear@26: 	 * it happened to be the last row of the image, the application would
nuclear@26: 	 * think we were done.
nuclear@26: 	 */
nuclear@26: 	if (! main->suspended) {
nuclear@26: 	  (*in_row_ctr)--;
nuclear@26: 	  main->suspended = TRUE;
nuclear@26: 	}
nuclear@26: 	return;
nuclear@26:       }
nuclear@26:       /* We did finish the row.  Undo our little suspension hack if a previous
nuclear@26:        * call suspended; then mark the main buffer empty.
nuclear@26:        */
nuclear@26:       if (main->suspended) {
nuclear@26: 	(*in_row_ctr)++;
nuclear@26: 	main->suspended = FALSE;
nuclear@26:       }
nuclear@26:     }
nuclear@26: 
nuclear@26:     /* If get here, we are done with this iMCU row.  Mark buffer empty. */
nuclear@26:     main->rowgroup_ctr = 0;
nuclear@26:     main->cur_iMCU_row++;
nuclear@26:   }
nuclear@26: }
nuclear@26: 
nuclear@26: #endif /* FULL_MAIN_BUFFER_SUPPORTED */
nuclear@26: 
nuclear@26: 
nuclear@26: /*
nuclear@26:  * Initialize main buffer controller.
nuclear@26:  */
nuclear@26: 
nuclear@26: GLOBAL(void)
nuclear@26: jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer)
nuclear@26: {
nuclear@26:   my_main_ptr main;
nuclear@26:   int ci;
nuclear@26:   jpeg_component_info *compptr;
nuclear@26: 
nuclear@26:   main = (my_main_ptr)
nuclear@26:     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26: 				SIZEOF(my_main_controller));
nuclear@26:   cinfo->main = (struct jpeg_c_main_controller *) main;
nuclear@26:   main->pub.start_pass = start_pass_main;
nuclear@26: 
nuclear@26:   /* We don't need to create a buffer in raw-data mode. */
nuclear@26:   if (cinfo->raw_data_in)
nuclear@26:     return;
nuclear@26: 
nuclear@26:   /* Create the buffer.  It holds downsampled data, so each component
nuclear@26:    * may be of a different size.
nuclear@26:    */
nuclear@26:   if (need_full_buffer) {
nuclear@26: #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@26:     /* Allocate a full-image virtual array for each component */
nuclear@26:     /* Note we pad the bottom to a multiple of the iMCU height */
nuclear@26:     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@26: 	 ci++, compptr++) {
nuclear@26:       main->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
nuclear@26: 	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
nuclear@26: 	 compptr->width_in_blocks * DCTSIZE,
nuclear@26: 	 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
nuclear@26: 				(long) compptr->v_samp_factor) * DCTSIZE,
nuclear@26: 	 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
nuclear@26:     }
nuclear@26: #else
nuclear@26:     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@26: #endif
nuclear@26:   } else {
nuclear@26: #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@26:     main->whole_image[0] = NULL; /* flag for no virtual arrays */
nuclear@26: #endif
nuclear@26:     /* Allocate a strip buffer for each component */
nuclear@26:     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@26: 	 ci++, compptr++) {
nuclear@26:       main->buffer[ci] = (*cinfo->mem->alloc_sarray)
nuclear@26: 	((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@26: 	 compptr->width_in_blocks * DCTSIZE,
nuclear@26: 	 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
nuclear@26:     }
nuclear@26:   }
nuclear@26: }