jdapistd.cpp

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/* +------------------------------------------------------------------------+
   |                     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"

/* Forward declarations */
LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo));

/*
 * Decompression initialization.
 * jpeg_read_header must be completed before calling this.
 *
 * If a multipass operating mode was selected, this will do all but the
 * last pass, and thus may take a great deal of time.
 *
 * Returns FALSE if suspended.  The return value need be inspected only if
 * a suspending data source is used.
 */

GLOBAL(boolean)
jpeg_start_decompress(j_decompress_ptr cinfo)
{
        if (cinfo->global_state == DSTATE_READY)
        {
                /* First call: initialize master control, select active modules */
                jinit_master_decompress(cinfo);
                if (cinfo->buffered_image)
                {
                        /* No more work here; expecting jpeg_start_output next */
                        cinfo->global_state = DSTATE_BUFIMAGE;
                        return TRUE;
                }
                cinfo->global_state = DSTATE_PRELOAD;
        }
        if (cinfo->global_state == DSTATE_PRELOAD)
        {
                /* If file has multiple scans, absorb them all into the coef buffer */
                if (cinfo->inputctl->has_multiple_scans)
                {
#ifdef D_MULTISCAN_FILES_SUPPORTED
                        for (;;)
                        {
                                int retcode;
                                /* Call progress monitor hook if present */
                                if (cinfo->progress != nullptr)
                                        (*cinfo->progress->progress_monitor)((j_common_ptr)cinfo);
                                /* Absorb some more input */
                                retcode = (*cinfo->inputctl->consume_input)(cinfo);
                                if (retcode == JPEG_SUSPENDED) return FALSE;
                                if (retcode == JPEG_REACHED_EOI) break;
                                /* Advance progress counter if appropriate */
                                if (cinfo->progress != nullptr &&
                                        (retcode == JPEG_ROW_COMPLETED ||
                                         retcode == JPEG_REACHED_SOS))
                                {
                                        if (++cinfo->progress->pass_counter >=
                                                cinfo->progress->pass_limit)
                                        {
                                                /* jdmaster underestimated number of scans; ratchet up
                                                 * one scan */
                                                cinfo->progress->pass_limit +=
                                                        (long)cinfo->total_iMCU_rows;
                                        }
                                }
                        }
#else
                        ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif /* D_MULTISCAN_FILES_SUPPORTED */
                }
                cinfo->output_scan_number = cinfo->input_scan_number;
        }
        else if (cinfo->global_state != DSTATE_PRESCAN)
                ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
        /* Perform any dummy output passes, and set up for the final pass */
        return output_pass_setup(cinfo);
}

/*
 * Set up for an output pass, and perform any dummy pass(es) needed.
 * Common subroutine for jpeg_start_decompress and jpeg_start_output.
 * Entry: global_state = DSTATE_PRESCAN only if previously suspended.
 * Exit: If done, returns TRUE and sets global_state for proper output mode.
 *       If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN.
 */

LOCAL(boolean)
output_pass_setup(j_decompress_ptr cinfo)
{
        if (cinfo->global_state != DSTATE_PRESCAN)
        {
                /* First call: do pass setup */
                (*cinfo->master->prepare_for_output_pass)(cinfo);
                cinfo->output_scanline = 0;
                cinfo->global_state = DSTATE_PRESCAN;
        }
        /* Loop over any required dummy passes */
        while (cinfo->master->is_dummy_pass)
        {
#ifdef QUANT_2PASS_SUPPORTED
                /* Crank through the dummy pass */
                while (cinfo->output_scanline < cinfo->output_height)
                {
                        JDIMENSION last_scanline;
                        /* Call progress monitor hook if present */
                        if (cinfo->progress != nullptr)
                        {
                                cinfo->progress->pass_counter = (long)cinfo->output_scanline;
                                cinfo->progress->pass_limit = (long)cinfo->output_height;
                                (*cinfo->progress->progress_monitor)((j_common_ptr)cinfo);
                        }
                        /* Process some data */
                        last_scanline = cinfo->output_scanline;
                        (*cinfo->main->process_data)(
                                cinfo, (JSAMPARRAY) nullptr, &cinfo->output_scanline,
                                (JDIMENSION)0);
                        if (cinfo->output_scanline == last_scanline)
                                return FALSE; /* No progress made, must suspend */
                }
                /* Finish up dummy pass, and set up for another one */
                (*cinfo->master->finish_output_pass)(cinfo);
                (*cinfo->master->prepare_for_output_pass)(cinfo);
                cinfo->output_scanline = 0;
#else
                ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif /* QUANT_2PASS_SUPPORTED */
        }
        /* Ready for application to drive output pass through
         * jpeg_read_scanlines or jpeg_read_raw_data.
         */
        cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING;
        return TRUE;
}

/*
 * Read some scanlines of data from the JPEG decompressor.
 *
 * The return value will be the number of lines actually read.
 * This may be less than the number requested in several cases,
 * including bottom of image, data source suspension, and operating
 * modes that emit multiple scanlines at a time.
 *
 * Note: we warn about excess calls to jpeg_read_scanlines() since
 * this likely signals an application programmer error.  However,
 * an oversize buffer (max_lines > scanlines remaining) is not an error.
 */

GLOBAL(JDIMENSION)
jpeg_read_scanlines(
        j_decompress_ptr cinfo, JSAMPARRAY scanlines, JDIMENSION max_lines)
{
        JDIMENSION row_ctr;

        if (cinfo->global_state != DSTATE_SCANNING)
                ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
        if (cinfo->output_scanline >= cinfo->output_height)
        {
                WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
                return 0;
        }

        /* Call progress monitor hook if present */
        if (cinfo->progress != nullptr)
        {
                cinfo->progress->pass_counter = (long)cinfo->output_scanline;
                cinfo->progress->pass_limit = (long)cinfo->output_height;
                (*cinfo->progress->progress_monitor)((j_common_ptr)cinfo);
        }

        /* Process some data */
        row_ctr = 0;
        (*cinfo->main->process_data)(cinfo, scanlines, &row_ctr, max_lines);
        cinfo->output_scanline += row_ctr;
        return row_ctr;
}

/*
 * Alternate entry point to read raw data.
 * Processes exactly one iMCU row per call, unless suspended.
 */

GLOBAL(JDIMENSION)
jpeg_read_raw_data(
        j_decompress_ptr cinfo, JSAMPIMAGE data, JDIMENSION max_lines)
{
        JDIMENSION lines_per_iMCU_row;

        if (cinfo->global_state != DSTATE_RAW_OK)
                ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
        if (cinfo->output_scanline >= cinfo->output_height)
        {
                WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
                return 0;
        }

        /* Call progress monitor hook if present */
        if (cinfo->progress != nullptr)
        {
                cinfo->progress->pass_counter = (long)cinfo->output_scanline;
                cinfo->progress->pass_limit = (long)cinfo->output_height;
                (*cinfo->progress->progress_monitor)((j_common_ptr)cinfo);
        }

        /* Verify that at least one iMCU row can be returned. */
        lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size;
        if (max_lines < lines_per_iMCU_row) ERREXIT(cinfo, JERR_BUFFER_SIZE);

        /* Decompress directly into user's buffer. */
        if (!(*cinfo->coef->decompress_data)(cinfo, data))
                return 0; /* suspension forced, can do nothing more */

        /* OK, we processed one iMCU row. */
        cinfo->output_scanline += lines_per_iMCU_row;
        return lines_per_iMCU_row;
}

/* Additional entry points for buffered-image mode. */

#ifdef D_MULTISCAN_FILES_SUPPORTED

/*
 * Initialize for an output pass in buffered-image mode.
 */

GLOBAL(boolean)
jpeg_start_output(j_decompress_ptr cinfo, int scan_number)
{
        if (cinfo->global_state != DSTATE_BUFIMAGE &&
                cinfo->global_state != DSTATE_PRESCAN)
                ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
        /* Limit scan number to valid range */
        if (scan_number <= 0) scan_number = 1;
        if (cinfo->inputctl->eoi_reached && scan_number > cinfo->input_scan_number)
                scan_number = cinfo->input_scan_number;
        cinfo->output_scan_number = scan_number;
        /* Perform any dummy output passes, and set up for the real pass */
        return output_pass_setup(cinfo);
}

/*
 * Finish up after an output pass in buffered-image mode.
 *
 * Returns FALSE if suspended.  The return value need be inspected only if
 * a suspending data source is used.
 */

GLOBAL(boolean)
jpeg_finish_output(j_decompress_ptr cinfo)
{
        if ((cinfo->global_state == DSTATE_SCANNING ||
                 cinfo->global_state == DSTATE_RAW_OK) &&
                cinfo->buffered_image)
        {
                /* Terminate this pass. */
                /* We do not require the whole pass to have been completed. */
                (*cinfo->master->finish_output_pass)(cinfo);
                cinfo->global_state = DSTATE_BUFPOST;
        }
        else if (cinfo->global_state != DSTATE_BUFPOST)
        {
                /* BUFPOST = repeat call after a suspension, anything else is error */
                ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
        }
        /* Read markers looking for SOS or EOI */
        while (cinfo->input_scan_number <= cinfo->output_scan_number &&
                   !cinfo->inputctl->eoi_reached)
        {
                if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED)
                        return FALSE; /* Suspend, come back later */
        }
        cinfo->global_state = DSTATE_BUFIMAGE;
        return TRUE;
}

#endif /* D_MULTISCAN_FILES_SUPPORTED */