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 /*

  * jcmainct.c

  *

  * Copyright (C) 1994-1996, Thomas G. Lane.

  * This file is part of the Independent JPEG Group's software.

  * For conditions of distribution and use, see the accompanying README file.

  *

  * This file contains the main buffer controller for compression.

  * The main buffer lies between the pre-processor and the JPEG

  * compressor proper; it holds downsampled data in the JPEG colorspace.

  */

 #define JPEG_INTERNALS

 #include "jinclude.h"

 #include "jpeglib.h"

 /* Note: currently, there is no operating mode in which a full-image buffer

  * is needed at this step.  If there were, that mode could not be used with

  * "raw data" input, since this module is bypassed in that case.  However,

  * we've left the code here for possible use in special applications.

  */

 #undef FULL_MAIN_BUFFER_SUPPORTED

 /* Private buffer controller object */

 typedef struct {

   struct jpeg_c_main_controller pub; /* public fields */

   JDIMENSION cur_iMCU_row;	/* number of current iMCU row */

   JDIMENSION rowgroup_ctr;	/* counts row groups received in iMCU row */

   boolean suspended;		/* remember if we suspended output */

   J_BUF_MODE pass_mode;		/* current operating mode */

   /* If using just a strip buffer, this points to the entire set of buffers

    * (we allocate one for each component).  In the full-image case, this

    * points to the currently accessible strips of the virtual arrays.

    */

   JSAMPARRAY buffer[MAX_COMPONENTS];

 #ifdef FULL_MAIN_BUFFER_SUPPORTED

   /* If using full-image storage, this array holds pointers to virtual-array

    * control blocks for each component.  Unused if not full-image storage.

    */

   jvirt_sarray_ptr whole_image[MAX_COMPONENTS];

 #endif

 } my_main_controller;

 typedef my_main_controller * my_main_ptr;

 /* Forward declarations */

 METHODDEF(void) process_data_simple_main

 	JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,

 	     JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));

 #ifdef FULL_MAIN_BUFFER_SUPPORTED

 METHODDEF(void) process_data_buffer_main

 	JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,

 	     JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));

 #endif

 /*

  * Initialize for a processing pass.

  */

 METHODDEF(void)

 start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode)

 {

   my_main_ptr main_ptr = (my_main_ptr) cinfo->main;

   /* Do nothing in raw-data mode. */

   if (cinfo->raw_data_in)

     return;

   main_ptr->cur_iMCU_row = 0;	/* initialize counters */

   main_ptr->rowgroup_ctr = 0;

   main_ptr->suspended = FALSE;

   main_ptr->pass_mode = pass_mode;	/* save mode for use by process_data */

   switch (pass_mode) {

   case JBUF_PASS_THRU:

 #ifdef FULL_MAIN_BUFFER_SUPPORTED

     if (main_ptr->whole_image[0] != NULL)

       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);

 #endif

     main_ptr->pub.process_data = process_data_simple_main;

     break;

 #ifdef FULL_MAIN_BUFFER_SUPPORTED

   case JBUF_SAVE_SOURCE:

   case JBUF_CRANK_DEST:

   case JBUF_SAVE_AND_PASS:

     if (main_ptr->whole_image[0] == NULL)

       ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);

     main_ptr->pub.process_data = process_data_buffer_main;

     break;

 #endif

   default:

     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);

     break;

   }

 }

 /*

  * Process some data.

  * This routine handles the simple pass-through mode,

  * where we have only a strip buffer.

  */

 METHODDEF(void)

 process_data_simple_main (j_compress_ptr cinfo,

 			  JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,

 			  JDIMENSION in_rows_avail)

 {

   my_main_ptr main_ptr = (my_main_ptr) cinfo->main;

   while (main_ptr->cur_iMCU_row < cinfo->total_iMCU_rows) {

     /* Read input data if we haven't filled the main buffer yet */

     if (main_ptr->rowgroup_ctr < DCTSIZE)

       (*cinfo->prep->pre_process_data) (cinfo,

 					input_buf, in_row_ctr, in_rows_avail,

 					main_ptr->buffer, &main_ptr->rowgroup_ctr,

 					(JDIMENSION) DCTSIZE);

     /* If we don't have a full iMCU row buffered, return to application for

      * more data.  Note that preprocessor will always pad to fill the iMCU row

      * at the bottom of the image.

      */

     if (main_ptr->rowgroup_ctr != DCTSIZE)

       return;

     /* Send the completed row to the compressor */

     if (! (*cinfo->coef->compress_data) (cinfo, main_ptr->buffer)) {

       /* If compressor did not consume the whole row, then we must need to

        * suspend processing and return to the application.  In this situation

        * we pretend we didn't yet consume the last input row; otherwise, if

        * it happened to be the last row of the image, the application would

        * think we were done.

        */

       if (! main_ptr->suspended) {

 	(*in_row_ctr)--;

 	main_ptr->suspended = TRUE;

       }

       return;

     }

     /* We did finish the row.  Undo our little suspension hack if a previous

      * call suspended; then mark the main buffer empty.

      */

     if (main_ptr->suspended) {

       (*in_row_ctr)++;

       main_ptr->suspended = FALSE;

     }

     main_ptr->rowgroup_ctr = 0;

     main_ptr->cur_iMCU_row++;

   }

 }

 #ifdef FULL_MAIN_BUFFER_SUPPORTED

 /*

  * Process some data.

  * This routine handles all of the modes that use a full-size buffer.

  */

 METHODDEF(void)

 process_data_buffer_main (j_compress_ptr cinfo,

 			  JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,

 			  JDIMENSION in_rows_avail)

 {

   my_main_ptr main_ptr = (my_main_ptr) cinfo->main;

   int ci;

   jpeg_component_info *compptr;

   boolean writing = (main_ptr->pass_mode != JBUF_CRANK_DEST);

   while (main_ptr->cur_iMCU_row < cinfo->total_iMCU_rows) {

     /* Realign the virtual buffers if at the start of an iMCU row. */

     if (main_ptr->rowgroup_ctr == 0) {

       for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

 	   ci++, compptr++) {

 	main_ptr->buffer[ci] = (*cinfo->mem->access_virt_sarray)

 	  ((j_common_ptr) cinfo, main_ptr->whole_image[ci],

 	   main_ptr->cur_iMCU_row * (compptr->v_samp_factor * DCTSIZE),

 	   (JDIMENSION) (compptr->v_samp_factor * DCTSIZE), writing);

       }

       /* In a read pass, pretend we just read some source data. */

       if (! writing) {

 	*in_row_ctr += cinfo->max_v_samp_factor * DCTSIZE;

 	main_ptr->rowgroup_ctr = DCTSIZE;

       }

     }

     /* If a write pass, read input data until the current iMCU row is full. */

     /* Note: preprocessor will pad if necessary to fill the last iMCU row. */

     if (writing) {

       (*cinfo->prep->pre_process_data) (cinfo,

 					input_buf, in_row_ctr, in_rows_avail,

 					main_ptr->buffer, &main_ptr->rowgroup_ctr,

 					(JDIMENSION) DCTSIZE);

       /* Return to application if we need more data to fill the iMCU row. */

       if (main_ptr->rowgroup_ctr < DCTSIZE)

 	return;

     }

     /* Emit data, unless this is a sink-only pass. */

     if (main_ptr->pass_mode != JBUF_SAVE_SOURCE) {

       if (! (*cinfo->coef->compress_data) (cinfo, main_ptr->buffer)) {

 	/* If compressor did not consume the whole row, then we must need to

 	 * suspend processing and return to the application.  In this situation

 	 * we pretend we didn't yet consume the last input row; otherwise, if

 	 * it happened to be the last row of the image, the application would

 	 * think we were done.

 	 */

 	if (! main_ptr->suspended) {

 	  (*in_row_ctr)--;

 	  main_ptr->suspended = TRUE;

 	}

 	return;

       }

       /* We did finish the row.  Undo our little suspension hack if a previous

        * call suspended; then mark the main buffer empty.

        */

       if (main_ptr->suspended) {

 	(*in_row_ctr)++;

 	main_ptr->suspended = FALSE;

       }

     }

     /* If get here, we are done with this iMCU row.  Mark buffer empty. */

     main_ptr->rowgroup_ctr = 0;

     main_ptr->cur_iMCU_row++;

   }

 }

 #endif /* FULL_MAIN_BUFFER_SUPPORTED */

 /*

  * Initialize main buffer controller.

  */

 GLOBAL(void)

 jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer)

 {

   my_main_ptr main_ptr;

   int ci;

   jpeg_component_info *compptr;

   main_ptr = (my_main_ptr)

     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

 				SIZEOF(my_main_controller));

   cinfo->main = (struct jpeg_c_main_controller *) main_ptr;

   main_ptr->pub.start_pass = start_pass_main;

   /* We don't need to create a buffer in raw-data mode. */

   if (cinfo->raw_data_in)

     return;

   /* Create the buffer.  It holds downsampled data, so each component

    * may be of a different size.

    */

   if (need_full_buffer) {

 #ifdef FULL_MAIN_BUFFER_SUPPORTED

     /* Allocate a full-image virtual array for each component */

     /* Note we pad the bottom to a multiple of the iMCU height */

     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

 	 ci++, compptr++) {

       main_ptr->whole_image[ci] = (*cinfo->mem->request_virt_sarray)

 	((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,

 	 compptr->width_in_blocks * DCTSIZE,

 	 (JDIMENSION) jround_up((long) compptr->height_in_blocks,

 				(long) compptr->v_samp_factor) * DCTSIZE,

 	 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));

     }

 #else

     ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);

 #endif

   } else {

 #ifdef FULL_MAIN_BUFFER_SUPPORTED

     main_ptr->whole_image[0] = NULL; /* flag for no virtual arrays */

 #endif

     /* Allocate a strip buffer for each component */

     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;

 	 ci++, compptr++) {

       main_ptr->buffer[ci] = (*cinfo->mem->alloc_sarray)

 	((j_common_ptr) cinfo, JPOOL_IMAGE,

 	 compptr->width_in_blocks * DCTSIZE,

 	 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));

     }

   }

 }