/*

 * jcmainct.c

 *

 * This file was part of the Independent JPEG Group's software:

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

 * It was modified by The libjpeg-turbo Project to include only code relevant

 * to libjpeg-turbo.

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

 * 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"

/* 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];

} my_main_controller;

typedef my_main_controller *my_main_ptr;

/* Forward declarations */

METHODDEF(void) process_data_simple_main(j_compress_ptr cinfo,

                                         JSAMPARRAY input_buf,

                                         JDIMENSION *in_row_ctr,

                                         JDIMENSION in_rows_avail);

/*

 * 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;

  if (pass_mode != JBUF_PASS_THRU)

    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);

  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 */

  main_ptr->pub.process_data = process_data_simple_main;

}

/*

 * 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++;

  }

}

/*

 * 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) {

    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);

  } else {

    /* 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));

    }

  }

}