jdmaster.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"

/* Private state */

typedef struct
{
        struct jpeg_decomp_master pub; /* public fields */

        int pass_number; /* # of passes completed */

        boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */

        /* Saved references to initialized quantizer modules,
         * in case we need to switch modes.
         */
        struct jpeg_color_quantizer* quantizer_1pass;
        struct jpeg_color_quantizer* quantizer_2pass;
} my_decomp_master;

typedef my_decomp_master* my_master_ptr;

/*
 * Determine whether merged upsample/color conversion should be used.
 * CRUCIAL: this must match the actual capabilities of jdmerge.c!
 */

LOCAL(boolean)
use_merged_upsample(j_decompress_ptr cinfo)
{
#ifdef UPSAMPLE_MERGING_SUPPORTED
        /* Merging is the equivalent of plain box-filter upsampling */
        if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling) return FALSE;
        /* jdmerge.c only supports YCC=>RGB color conversion */
        if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 ||
                cinfo->out_color_space != JCS_RGB ||
                cinfo->out_color_components != RGB_PIXELSIZE)
                return FALSE;
        /* and it only handles 2h1v or 2h2v sampling ratios */
        if (cinfo->comp_info[0].h_samp_factor != 2 ||
                cinfo->comp_info[1].h_samp_factor != 1 ||
                cinfo->comp_info[2].h_samp_factor != 1 ||
                cinfo->comp_info[0].v_samp_factor > 2 ||
                cinfo->comp_info[1].v_samp_factor != 1 ||
                cinfo->comp_info[2].v_samp_factor != 1)
                return FALSE;
        /* furthermore, it doesn't work if we've scaled the IDCTs differently */
        if (cinfo->comp_info[0].DCT_scaled_size != cinfo->min_DCT_scaled_size ||
                cinfo->comp_info[1].DCT_scaled_size != cinfo->min_DCT_scaled_size ||
                cinfo->comp_info[2].DCT_scaled_size != cinfo->min_DCT_scaled_size)
                return FALSE;
        /* ??? also need to test for upsample-time rescaling, when & if supported */
        return TRUE; /* by golly, it'll work... */
#else
        return FALSE;
#endif
}

/*
 * Compute output image dimensions and related values.
 * NOTE: this is exported for possible use by application.
 * Hence it mustn't do anything that can't be done twice.
 * Also note that it may be called before the master module is initialized!
 */

GLOBAL(void)
jpeg_calc_output_dimensions(j_decompress_ptr cinfo)
/* Do computations that are needed before master selection phase */
{
#ifdef IDCT_SCALING_SUPPORTED
        int ci;
        jpeg_component_info* compptr;
#endif

        /* Prevent application from calling me at wrong times */
        if (cinfo->global_state != DSTATE_READY)
                ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

#ifdef IDCT_SCALING_SUPPORTED

        /* Compute actual output image dimensions and DCT scaling choices. */
        if (cinfo->scale_num * 8 <= cinfo->scale_denom)
        {
                /* Provide 1/8 scaling */
                cinfo->output_width =
                        (JDIMENSION)jdiv_round_up((long)cinfo->image_width, 8L);
                cinfo->output_height =
                        (JDIMENSION)jdiv_round_up((long)cinfo->image_height, 8L);
                cinfo->min_DCT_scaled_size = 1;
        }
        else if (cinfo->scale_num * 4 <= cinfo->scale_denom)
        {
                /* Provide 1/4 scaling */
                cinfo->output_width =
                        (JDIMENSION)jdiv_round_up((long)cinfo->image_width, 4L);
                cinfo->output_height =
                        (JDIMENSION)jdiv_round_up((long)cinfo->image_height, 4L);
                cinfo->min_DCT_scaled_size = 2;
        }
        else if (cinfo->scale_num * 2 <= cinfo->scale_denom)
        {
                /* Provide 1/2 scaling */
                cinfo->output_width =
                        (JDIMENSION)jdiv_round_up((long)cinfo->image_width, 2L);
                cinfo->output_height =
                        (JDIMENSION)jdiv_round_up((long)cinfo->image_height, 2L);
                cinfo->min_DCT_scaled_size = 4;
        }
        else
        {
                /* Provide 1/1 scaling */
                cinfo->output_width = cinfo->image_width;
                cinfo->output_height = cinfo->image_height;
                cinfo->min_DCT_scaled_size = DCTSIZE;
        }
        /* In selecting the actual DCT scaling for each component, we try to
         * scale up the chroma components via IDCT scaling rather than upsampling.
         * This saves time if the upsampler gets to use 1:1 scaling.
         * Note this code assumes that the supported DCT scalings are powers of 2.
         */
        for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
                 ci++, compptr++)
        {
                int ssize = cinfo->min_DCT_scaled_size;
                while (ssize < DCTSIZE &&
                           (compptr->h_samp_factor * ssize * 2 <=
                                cinfo->max_h_samp_factor * cinfo->min_DCT_scaled_size) &&
                           (compptr->v_samp_factor * ssize * 2 <=
                                cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size))
                {
                        ssize = ssize * 2;
                }
                compptr->DCT_scaled_size = ssize;
        }

        /* Recompute downsampled dimensions of components;
         * application needs to know these if using raw downsampled data.
         */
        for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
                 ci++, compptr++)
        {
                /* Size in samples, after IDCT scaling */
                compptr->downsampled_width = (JDIMENSION)jdiv_round_up(
                        (long)cinfo->image_width *
                                (long)(compptr->h_samp_factor * compptr->DCT_scaled_size),
                        (long)(cinfo->max_h_samp_factor * DCTSIZE));
                compptr->downsampled_height = (JDIMENSION)jdiv_round_up(
                        (long)cinfo->image_height *
                                (long)(compptr->v_samp_factor * compptr->DCT_scaled_size),
                        (long)(cinfo->max_v_samp_factor * DCTSIZE));
        }

#else /* !IDCT_SCALING_SUPPORTED */

        /* Hardwire it to "no scaling" */
        cinfo->output_width = cinfo->image_width;
        cinfo->output_height = cinfo->image_height;
/* jdinput.c has already initialized DCT_scaled_size to DCTSIZE,
 * and has computed unscaled downsampled_width and downsampled_height.
 */

#endif /* IDCT_SCALING_SUPPORTED */

        /* Report number of components in selected colorspace. */
        /* Probably this should be in the color conversion module... */
        switch (cinfo->out_color_space)
        {
                case JCS_GRAYSCALE:
                        cinfo->out_color_components = 1;
                        break;
                case JCS_RGB:
#if RGB_PIXELSIZE != 3
                        cinfo->out_color_components = RGB_PIXELSIZE;
                        break;
#endif /* else share code with YCbCr */
                case JCS_YCbCr:
                        cinfo->out_color_components = 3;
                        break;
                case JCS_CMYK:
                case JCS_YCCK:
                        cinfo->out_color_components = 4;
                        break;
                default: /* else must be same colorspace as in file */
                        cinfo->out_color_components = cinfo->num_components;
                        break;
        }
        cinfo->output_components =
                (cinfo->quantize_colors ? 1 : cinfo->out_color_components);

        /* See if upsampler will want to emit more than one row at a time */
        if (use_merged_upsample(cinfo))
                cinfo->rec_outbuf_height = cinfo->max_v_samp_factor;
        else
                cinfo->rec_outbuf_height = 1;
}

/*
 * Several decompression processes need to range-limit values to the range
 * 0..MAXJSAMPLE; the input value may fall somewhat outside this range
 * due to noise introduced by quantization, roundoff error, etc.  These
 * processes are inner loops and need to be as fast as possible.  On most
 * machines, particularly CPUs with pipelines or instruction prefetch,
 * a (subscript-check-less) C table lookup
 *              x = sample_range_limit[x];
 * is faster than explicit tests
 *              if (x < 0)  x = 0;
 *              else if (x > MAXJSAMPLE)  x = MAXJSAMPLE;
 * These processes all use a common table prepared by the routine below.
 *
 * For most steps we can mathematically guarantee that the initial value
 * of x is within MAXJSAMPLE+1 of the legal range, so a table running from
 * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient.  But for the initial
 * limiting step (just after the IDCT), a wildly out-of-range value is
 * possible if the input data is corrupt.  To avoid any chance of indexing
 * off the end of memory and getting a bad-pointer trap, we perform the
 * post-IDCT limiting thus:
 *              x = range_limit[x & MASK];
 * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit
 * samples.  Under normal circumstances this is more than enough range and
 * a correct output will be generated; with bogus input data the mask will
 * cause wraparound, and we will safely generate a bogus-but-in-range output.
 * For the post-IDCT step, we want to convert the data from signed to unsigned
 * representation by adding CENTERJSAMPLE at the same time that we limit it.
 * So the post-IDCT limiting table ends up looking like this:
 *   CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE,
 *   MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
 *   0          (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times),
 *   0,1,...,CENTERJSAMPLE-1
 * Negative inputs select values from the upper half of the table after
 * masking.
 *
 * We can save some space by overlapping the start of the post-IDCT table
 * with the simpler range limiting table.  The post-IDCT table begins at
 * sample_range_limit + CENTERJSAMPLE.
 *
 * Note that the table is allocated in near data space on PCs; it's small
 * enough and used often enough to justify this.
 */

LOCAL(void)
prepare_range_limit_table(j_decompress_ptr cinfo)
/* Allocate and fill in the sample_range_limit table */
{
        JSAMPLE* table;
        int i;

        table = (JSAMPLE*)(*cinfo->mem->alloc_small)(
                (j_common_ptr)cinfo, JPOOL_IMAGE,
                (5 * (MAXJSAMPLE + 1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE));
        table += (MAXJSAMPLE + 1); /* allow negative subscripts of simple table */
        cinfo->sample_range_limit = table;
        /* First segment of "simple" table: limit[x] = 0 for x < 0 */
        MEMZERO(table - (MAXJSAMPLE + 1), (MAXJSAMPLE + 1) * SIZEOF(JSAMPLE));
        /* Main part of "simple" table: limit[x] = x */
        for (i = 0; i <= MAXJSAMPLE; i++) table[i] = (JSAMPLE)i;
        table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */
        /* End of simple table, rest of first half of post-IDCT table */
        for (i = CENTERJSAMPLE; i < 2 * (MAXJSAMPLE + 1); i++)
                table[i] = MAXJSAMPLE;
        /* Second half of post-IDCT table */
        MEMZERO(
                table + (2 * (MAXJSAMPLE + 1)),
                (2 * (MAXJSAMPLE + 1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE));
        MEMCOPY(
                table + (4 * (MAXJSAMPLE + 1) - CENTERJSAMPLE),
                cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE));
}

/*
 * Master selection of decompression modules.
 * This is done once at jpeg_start_decompress time.  We determine
 * which modules will be used and give them appropriate initialization calls.
 * We also initialize the decompressor input side to begin consuming data.
 *
 * Since jpeg_read_header has finished, we know what is in the SOF
 * and (first) SOS markers.  We also have all the application parameter
 * settings.
 */

LOCAL(void)
master_selection(j_decompress_ptr cinfo)
{
        my_master_ptr master = (my_master_ptr)cinfo->master;
        boolean use_c_buffer;
        long samplesperrow;
        JDIMENSION jd_samplesperrow;

        /* Initialize dimensions and other stuff */
        jpeg_calc_output_dimensions(cinfo);
        prepare_range_limit_table(cinfo);

        /* Width of an output scanline must be representable as JDIMENSION. */
        samplesperrow =
                (long)cinfo->output_width * (long)cinfo->out_color_components;
        jd_samplesperrow = (JDIMENSION)samplesperrow;
        if ((long)jd_samplesperrow != samplesperrow)
                ERREXIT(cinfo, JERR_WIDTH_OVERFLOW);

        /* Initialize my private state */
        master->pass_number = 0;
        master->using_merged_upsample = use_merged_upsample(cinfo);

        /* Color quantizer selection */
        master->quantizer_1pass = nullptr;
        master->quantizer_2pass = nullptr;
        /* No mode changes if not using buffered-image mode. */
        if (!cinfo->quantize_colors || !cinfo->buffered_image)
        {
                cinfo->enable_1pass_quant = FALSE;
                cinfo->enable_external_quant = FALSE;
                cinfo->enable_2pass_quant = FALSE;
        }
        if (cinfo->quantize_colors)
        {
                if (cinfo->raw_data_out) ERREXIT(cinfo, JERR_NOTIMPL);
                /* 2-pass quantizer only works in 3-component color space. */
                if (cinfo->out_color_components != 3)
                {
                        cinfo->enable_1pass_quant = TRUE;
                        cinfo->enable_external_quant = FALSE;
                        cinfo->enable_2pass_quant = FALSE;
                        cinfo->colormap = nullptr;
                }
                else if (cinfo->colormap != nullptr)
                {
                        cinfo->enable_external_quant = TRUE;
                }
                else if (cinfo->two_pass_quantize)
                {
                        cinfo->enable_2pass_quant = TRUE;
                }
                else
                {
                        cinfo->enable_1pass_quant = TRUE;
                }

                if (cinfo->enable_1pass_quant)
                {
#ifdef QUANT_1PASS_SUPPORTED
                        jinit_1pass_quantizer(cinfo);
                        master->quantizer_1pass = cinfo->cquantize;
#else
                        ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
                }

                /* We use the 2-pass code to map to external colormaps. */
                if (cinfo->enable_2pass_quant || cinfo->enable_external_quant)
                {
#ifdef QUANT_2PASS_SUPPORTED
                        jinit_2pass_quantizer(cinfo);
                        master->quantizer_2pass = cinfo->cquantize;
#else
                        ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
                }
                /* If both quantizers are initialized, the 2-pass one is left active;
                 * this is necessary for starting with quantization to an external map.
                 */
        }

        /* Post-processing: in particular, color conversion first */
        if (!cinfo->raw_data_out)
        {
                if (master->using_merged_upsample)
                {
#ifdef UPSAMPLE_MERGING_SUPPORTED
                        jinit_merged_upsampler(cinfo); /* does color conversion too */
#else
                        ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
                }
                else
                {
                        jinit_color_deconverter(cinfo);
                        jinit_upsampler(cinfo);
                }
                jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant);
        }
        /* Inverse DCT */
        jinit_inverse_dct(cinfo);
        /* Entropy decoding: either Huffman or arithmetic coding. */
        if (cinfo->arith_code)
        {
                ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
        }
        else
        {
                if (cinfo->progressive_mode)
                {
#ifdef D_PROGRESSIVE_SUPPORTED
                        jinit_phuff_decoder(cinfo);
#else
                        ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
                }
                else
                        jinit_huff_decoder(cinfo);
        }

        /* Initialize principal buffer controllers. */
        use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image;
        jinit_d_coef_controller(cinfo, use_c_buffer);

        if (!cinfo->raw_data_out)
                jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */);

        /* We can now tell the memory manager to allocate virtual arrays. */
        (*cinfo->mem->realize_virt_arrays)((j_common_ptr)cinfo);

        /* Initialize input side of decompressor to consume first scan. */
        (*cinfo->inputctl->start_input_pass)(cinfo);

#ifdef D_MULTISCAN_FILES_SUPPORTED
        /* If jpeg_start_decompress will read the whole file, initialize
         * progress monitoring appropriately.  The input step is counted
         * as one pass.
         */
        if (cinfo->progress != nullptr && !cinfo->buffered_image &&
                cinfo->inputctl->has_multiple_scans)
        {
                int nscans;
                /* Estimate number of scans to set pass_limit. */
                if (cinfo->progressive_mode)
                {
                        /* Arbitrarily estimate 2 interleaved DC scans + 3 AC
                         * scans/component. */
                        nscans = 2 + 3 * cinfo->num_components;
                }
                else
                {
                        /* For a nonprogressive multiscan file, estimate 1 scan per
                         * component. */
                        nscans = cinfo->num_components;
                }
                cinfo->progress->pass_counter = 0L;
                cinfo->progress->pass_limit = (long)cinfo->total_iMCU_rows * nscans;
                cinfo->progress->completed_passes = 0;
                cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2);
                /* Count the input pass as done */
                master->pass_number++;
        }
#endif /* D_MULTISCAN_FILES_SUPPORTED */
}

/*
 * Per-pass setup.
 * This is called at the beginning of each output pass.  We determine which
 * modules will be active during this pass and give them appropriate
 * start_pass calls.  We also set is_dummy_pass to indicate whether this
 * is a "real" output pass or a dummy pass for color quantization.
 * (In the latter case, jdapistd.c will crank the pass to completion.)
 */

METHODDEF(void)
prepare_for_output_pass(j_decompress_ptr cinfo)
{
        my_master_ptr master = (my_master_ptr)cinfo->master;

        if (master->pub.is_dummy_pass)
        {
#ifdef QUANT_2PASS_SUPPORTED
                /* Final pass of 2-pass quantization */
                master->pub.is_dummy_pass = FALSE;
                (*cinfo->cquantize->start_pass)(cinfo, FALSE);
                (*cinfo->post->start_pass)(cinfo, JBUF_CRANK_DEST);
                (*cinfo->main->start_pass)(cinfo, JBUF_CRANK_DEST);
#else
                ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif /* QUANT_2PASS_SUPPORTED */
        }
        else
        {
                if (cinfo->quantize_colors && cinfo->colormap == nullptr)
                {
                        /* Select new quantization method */
                        if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant)
                        {
                                cinfo->cquantize = master->quantizer_2pass;
                                master->pub.is_dummy_pass = TRUE;
                        }
                        else if (cinfo->enable_1pass_quant)
                        {
                                cinfo->cquantize = master->quantizer_1pass;
                        }
                        else
                        {
                                ERREXIT(cinfo, JERR_MODE_CHANGE);
                        }
                }
                (*cinfo->idct->start_pass)(cinfo);
                (*cinfo->coef->start_output_pass)(cinfo);
                if (!cinfo->raw_data_out)
                {
                        if (!master->using_merged_upsample)
                                (*cinfo->cconvert->start_pass)(cinfo);
                        (*cinfo->upsample->start_pass)(cinfo);
                        if (cinfo->quantize_colors)
                                (*cinfo->cquantize->start_pass)(
                                        cinfo, master->pub.is_dummy_pass);
                        (*cinfo->post->start_pass)(
                                cinfo, (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS
                                                                                                  : JBUF_PASS_THRU));
                        (*cinfo->main->start_pass)(cinfo, JBUF_PASS_THRU);
                }
        }

        /* Set up progress monitor's pass info if present */
        if (cinfo->progress != nullptr)
        {
                cinfo->progress->completed_passes = master->pass_number;
                cinfo->progress->total_passes =
                        master->pass_number + (master->pub.is_dummy_pass ? 2 : 1);
                /* In buffered-image mode, we assume one more output pass if EOI not
                 * yet reached, but no more passes if EOI has been reached.
                 */
                if (cinfo->buffered_image && !cinfo->inputctl->eoi_reached)
                {
                        cinfo->progress->total_passes +=
                                (cinfo->enable_2pass_quant ? 2 : 1);
                }
        }
}

/*
 * Finish up at end of an output pass.
 */

METHODDEF(void)
finish_output_pass(j_decompress_ptr cinfo)
{
        my_master_ptr master = (my_master_ptr)cinfo->master;

        if (cinfo->quantize_colors) (*cinfo->cquantize->finish_pass)(cinfo);
        master->pass_number++;
}

#ifdef D_MULTISCAN_FILES_SUPPORTED

/*
 * Switch to a new external colormap between output passes.
 */

GLOBAL(void)
jpeg_new_colormap(j_decompress_ptr cinfo)
{
        my_master_ptr master = (my_master_ptr)cinfo->master;

        /* Prevent application from calling me at wrong times */
        if (cinfo->global_state != DSTATE_BUFIMAGE)
                ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

        if (cinfo->quantize_colors && cinfo->enable_external_quant &&
                cinfo->colormap != nullptr)
        {
                /* Select 2-pass quantizer for external colormap use */
                cinfo->cquantize = master->quantizer_2pass;
                /* Notify quantizer of colormap change */
                (*cinfo->cquantize->new_color_map)(cinfo);
                master->pub.is_dummy_pass = FALSE; /* just in case */
        }
        else
                ERREXIT(cinfo, JERR_MODE_CHANGE);
}

#endif /* D_MULTISCAN_FILES_SUPPORTED */

/*
 * Initialize master decompression control and select active modules.
 * This is performed at the start of jpeg_start_decompress.
 */

GLOBAL(void)
jinit_master_decompress(j_decompress_ptr cinfo)
{
        my_master_ptr master;

        master = (my_master_ptr)(*cinfo->mem->alloc_small)(
                (j_common_ptr)cinfo, JPOOL_IMAGE, SIZEOF(my_decomp_master));
        cinfo->master = (struct jpeg_decomp_master*)master;
        master->pub.prepare_for_output_pass = prepare_for_output_pass;
        master->pub.finish_output_pass = finish_output_pass;

        master->pub.is_dummy_pass = FALSE;

        master_selection(cinfo);
}