jcmainct.cpp

Go to the documentation of this file.

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "mrpt_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] != nullptr)
                                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] == nullptr)
                                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] = nullptr; /* 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));
                }
        }
}