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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 = (my_main_ptr) cinfo->main;

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

  if (cinfo->raw_data_in)

    return;

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

  main->rowgroup_ctr = 0;

  main->suspended = FALSE;

  main->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->whole_image[0] != NULL)

      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);

#endif

    main->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->whole_image[0] == NULL)

      ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);

    main->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 = (my_main_ptr) cinfo->main;

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

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

    if (main->rowgroup_ctr < DCTSIZE)

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

                                        input_buf, in_row_ctr, in_rows_avail,

                                        main->buffer, &main->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->rowgroup_ctr != DCTSIZE)

      return;

    /* Send the completed row to the compressor */

    if (! (*cinfo->coef->compress_data) (cinfo, main->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->suspended) {

        (*in_row_ctr)--;

        main->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->suspended) {

      (*in_row_ctr)++;

      main->suspended = FALSE;

    }

    main->rowgroup_ctr = 0;

    main->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 = (my_main_ptr) cinfo->main;

  int ci;

  jpeg_component_info *compptr;

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

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

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

    if (main->rowgroup_ctr == 0) {

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

           ci++, compptr++) {

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

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

           main->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->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->buffer, &main->rowgroup_ctr,

                                        (JDIMENSION) DCTSIZE);

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

      if (main->rowgroup_ctr < DCTSIZE)

        return;

    }

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

    if (main->pass_mode != JBUF_SAVE_SOURCE) {

      if (! (*cinfo->coef->compress_data) (cinfo, main->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->suspended) {

          (*in_row_ctr)--;

          main->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->suspended) {

        (*in_row_ctr)++;

        main->suspended = FALSE;

      }

    }

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

    main->rowgroup_ctr = 0;

    main->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;

  int ci;

  jpeg_component_info *compptr;

  main = (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;

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

        ((j_common_ptr) cinfo, JPOOL_IMAGE,

         compptr->width_in_blocks * DCTSIZE,

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

    }

  }

}