jctrans.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(void)
transencode_master_selection JPP(
        (j_compress_ptr cinfo, jvirt_barray_ptr* coef_arrays));
LOCAL(void)
transencode_coef_controller JPP(
        (j_compress_ptr cinfo, jvirt_barray_ptr* coef_arrays));

/*
 * Compression initialization for writing raw-coefficient data.
 * Before calling this, all parameters and a data destination must be set up.
 * Call jpeg_finish_compress() to actually write the data.
 *
 * The number of passed virtual arrays must match cinfo->num_components.
 * Note that the virtual arrays need not be filled or even realized at
 * the time write_coefficients is called; indeed, if the virtual arrays
 * were requested from this compression object's memory manager, they
 * typically will be realized during this routine and filled afterwards.
 */

GLOBAL(void)
jpeg_write_coefficients(j_compress_ptr cinfo, jvirt_barray_ptr* coef_arrays)
{
        if (cinfo->global_state != CSTATE_START)
                ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
        /* Mark all tables to be written */
        jpeg_suppress_tables(cinfo, FALSE);
        /* (Re)initialize error mgr and destination modules */
        (*cinfo->err->reset_error_mgr)((j_common_ptr)cinfo);
        (*cinfo->dest->init_destination)(cinfo);
        /* Perform master selection of active modules */
        transencode_master_selection(cinfo, coef_arrays);
        /* Wait for jpeg_finish_compress() call */
        cinfo->next_scanline = 0; /* so jpeg_write_marker works */
        cinfo->global_state = CSTATE_WRCOEFS;
}

/*
 * Initialize the compression object with default parameters,
 * then copy from the source object all parameters needed for lossless
 * transcoding.  Parameters that can be varied without loss (such as
 * scan script and Huffman optimization) are left in their default states.
 */

GLOBAL(void)
jpeg_copy_critical_parameters(j_decompress_ptr srcinfo, j_compress_ptr dstinfo)
{
        JQUANT_TBL** qtblptr;
        jpeg_component_info *incomp, *outcomp;
        JQUANT_TBL *c_quant, *slot_quant;
        int tblno, ci, coefi;

        /* Safety check to ensure start_compress not called yet. */
        if (dstinfo->global_state != CSTATE_START)
                ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state);
        /* Copy fundamental image dimensions */
        dstinfo->image_width = srcinfo->image_width;
        dstinfo->image_height = srcinfo->image_height;
        dstinfo->input_components = srcinfo->num_components;
        dstinfo->in_color_space = srcinfo->jpeg_color_space;
        /* Initialize all parameters to default values */
        jpeg_set_defaults(dstinfo);
        /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.
         * Fix it to get the right header markers for the image colorspace.
         */
        jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);
        dstinfo->data_precision = srcinfo->data_precision;
        dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
        /* Copy the source's quantization tables. */
        for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++)
        {
                if (srcinfo->quant_tbl_ptrs[tblno] != nullptr)
                {
                        qtblptr = &dstinfo->quant_tbl_ptrs[tblno];
                        if (*qtblptr == nullptr)
                                *qtblptr = jpeg_alloc_quant_table((j_common_ptr)dstinfo);
                        MEMCOPY(
                                (*qtblptr)->quantval, srcinfo->quant_tbl_ptrs[tblno]->quantval,
                                SIZEOF((*qtblptr)->quantval));
                        (*qtblptr)->sent_table = FALSE;
                }
        }
        /* Copy the source's per-component info.
         * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
         */
        dstinfo->num_components = srcinfo->num_components;
        if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)
                ERREXIT2(
                        dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
                        MAX_COMPONENTS);
        for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
                 ci < dstinfo->num_components; ci++, incomp++, outcomp++)
        {
                outcomp->component_id = incomp->component_id;
                outcomp->h_samp_factor = incomp->h_samp_factor;
                outcomp->v_samp_factor = incomp->v_samp_factor;
                outcomp->quant_tbl_no = incomp->quant_tbl_no;
                /* Make sure saved quantization table for component matches the qtable
                 * slot.  If not, the input file re-used this qtable slot.
                 * IJG encoder currently cannot duplicate this.
                 */
                tblno = outcomp->quant_tbl_no;
                if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||
                        srcinfo->quant_tbl_ptrs[tblno] == nullptr)
                        ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);
                slot_quant = srcinfo->quant_tbl_ptrs[tblno];
                c_quant = incomp->quant_table;
                if (c_quant != nullptr)
                {
                        for (coefi = 0; coefi < DCTSIZE2; coefi++)
                        {
                                if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])
                                        ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);
                        }
                }
                /* Note: we do not copy the source's Huffman table assignments;
                 * instead we rely on jpeg_set_colorspace to have made a suitable
                 * choice.
                 */
        }
        /* Also copy JFIF version and resolution information, if available.
         * Strictly speaking this isn't "critical" info, but it's nearly
         * always appropriate to copy it if available.  In particular,
         * if the application chooses to copy JFIF 1.02 extension markers from
         * the source file, we need to copy the version to make sure we don't
         * emit a file that has 1.02 extensions but a claimed version of 1.01.
         * We will *not*, however, copy version info from mislabeled "2.01" files.
         */
        if (srcinfo->saw_JFIF_marker)
        {
                if (srcinfo->JFIF_major_version == 1)
                {
                        dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
                        dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
                }
                dstinfo->density_unit = srcinfo->density_unit;
                dstinfo->X_density = srcinfo->X_density;
                dstinfo->Y_density = srcinfo->Y_density;
        }
}

/*
 * Master selection of compression modules for transcoding.
 * This substitutes for jcinit.c's initialization of the full compressor.
 */

LOCAL(void)
transencode_master_selection(
        j_compress_ptr cinfo, jvirt_barray_ptr* coef_arrays)
{
        /* Although we don't actually use input_components for transcoding,
         * jcmaster.c's initial_setup will complain if input_components is 0.
         */
        cinfo->input_components = 1;
        /* Initialize master control (includes parameter checking/processing) */
        jinit_c_master_control(cinfo, TRUE /* transcode only */);

        /* Entropy encoding: either Huffman or arithmetic coding. */
        if (cinfo->arith_code)
        {
                ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
        }
        else
        {
                if (cinfo->progressive_mode)
                {
#ifdef C_PROGRESSIVE_SUPPORTED
                        jinit_phuff_encoder(cinfo);
#else
                        ERREXIT(cinfo, JERR_NOT_COMPILED);
#endif
                }
                else
                        jinit_huff_encoder(cinfo);
        }

        /* We need a special coefficient buffer controller. */
        transencode_coef_controller(cinfo, coef_arrays);

        jinit_marker_writer(cinfo);

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

        /* Write the datastream header (SOI, JFIF) immediately.
         * Frame and scan headers are postponed till later.
         * This lets application insert special markers after the SOI.
         */
        (*cinfo->marker->write_file_header)(cinfo);
}

/*
 * The rest of this file is a special implementation of the coefficient
 * buffer controller.  This is similar to jccoefct.c, but it handles only
 * output from presupplied virtual arrays.  Furthermore, we generate any
 * dummy padding blocks on-the-fly rather than expecting them to be present
 * in the arrays.
 */

/* Private buffer controller object */

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

        JDIMENSION iMCU_row_num; /* iMCU row # within image */
        JDIMENSION mcu_ctr; /* counts MCUs processed in current row */
        int MCU_vert_offset; /* counts MCU rows within iMCU row */
        int MCU_rows_per_iMCU_row; /* number of such rows needed */

        /* Virtual block array for each component. */
        jvirt_barray_ptr* whole_image;

        /* Workspace for constructing dummy blocks at right/bottom edges. */
        JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];
} my_coef_controller;

typedef my_coef_controller* my_coef_ptr;

LOCAL(void)
start_iMCU_row(j_compress_ptr cinfo)
/* Reset within-iMCU-row counters for a new row */
{
        my_coef_ptr coef = (my_coef_ptr)cinfo->coef;

        /* In an interleaved scan, an MCU row is the same as an iMCU row.
         * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
         * But at the bottom of the image, process only what's left.
         */
        if (cinfo->comps_in_scan > 1)
        {
                coef->MCU_rows_per_iMCU_row = 1;
        }
        else
        {
                if (coef->iMCU_row_num < (cinfo->total_iMCU_rows - 1))
                        coef->MCU_rows_per_iMCU_row =
                                cinfo->cur_comp_info[0]->v_samp_factor;
                else
                        coef->MCU_rows_per_iMCU_row =
                                cinfo->cur_comp_info[0]->last_row_height;
        }

        coef->mcu_ctr = 0;
        coef->MCU_vert_offset = 0;
}

/*
 * Initialize for a processing pass.
 */

METHODDEF(void)
start_pass_coef(j_compress_ptr cinfo, J_BUF_MODE pass_mode)
{
        my_coef_ptr coef = (my_coef_ptr)cinfo->coef;

        if (pass_mode != JBUF_CRANK_DEST) ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);

        coef->iMCU_row_num = 0;
        start_iMCU_row(cinfo);
}

/*
 * Process some data.
 * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
 * per call, ie, v_samp_factor block rows for each component in the scan.
 * The data is obtained from the virtual arrays and fed to the entropy coder.
 * Returns TRUE if the iMCU row is completed, FALSE if suspended.
 *
 * NB: input_buf is ignored; it is likely to be a nullptr pointer.
 */

METHODDEF(boolean)
compress_output(j_compress_ptr cinfo, JSAMPIMAGE)
{
        my_coef_ptr coef = (my_coef_ptr)cinfo->coef;
        JDIMENSION MCU_col_num; /* index of current MCU within row */
        JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
        JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
        int blkn, ci, xindex, yindex, yoffset, blockcnt;
        JDIMENSION start_col;
        JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
        JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
        JBLOCKROW buffer_ptr;
        jpeg_component_info* compptr;

        /* Align the virtual buffers for the components used in this scan. */
        for (ci = 0; ci < cinfo->comps_in_scan; ci++)
        {
                compptr = cinfo->cur_comp_info[ci];
                buffer[ci] = (*cinfo->mem->access_virt_barray)(
                        (j_common_ptr)cinfo, coef->whole_image[compptr->component_index],
                        coef->iMCU_row_num * compptr->v_samp_factor,
                        (JDIMENSION)compptr->v_samp_factor, FALSE);
        }

        /* Loop to process one whole iMCU row */
        for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
                 yoffset++)
        {
                for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
                         MCU_col_num++)
                {
                        /* Construct list of pointers to DCT blocks belonging to this MCU */
                        blkn = 0; /* index of current DCT block within MCU */
                        for (ci = 0; ci < cinfo->comps_in_scan; ci++)
                        {
                                compptr = cinfo->cur_comp_info[ci];
                                start_col = MCU_col_num * compptr->MCU_width;
                                blockcnt = (MCU_col_num < last_MCU_col)
                                                           ? compptr->MCU_width
                                                           : compptr->last_col_width;
                                for (yindex = 0; yindex < compptr->MCU_height; yindex++)
                                {
                                        if (coef->iMCU_row_num < last_iMCU_row ||
                                                yindex + yoffset < compptr->last_row_height)
                                        {
                                                /* Fill in pointers to real blocks in this row */
                                                buffer_ptr = buffer[ci][yindex + yoffset] + start_col;
                                                for (xindex = 0; xindex < blockcnt; xindex++)
                                                        MCU_buffer[blkn++] = buffer_ptr++;
                                        }
                                        else
                                        {
                                                /* At bottom of image, need a whole row of dummy blocks
                                                 */
                                                xindex = 0;
                                        }
                                        /* Fill in any dummy blocks needed in this row.
                                         * Dummy blocks are filled in the same way as in jccoefct.c:
                                         * all zeroes in the AC entries, DC entries equal to
                                         * previous
                                         * block's DC value.  The init routine has already zeroed
                                         * the
                                         * AC entries, so we need only set the DC entries correctly.
                                         */
                                        for (; xindex < compptr->MCU_width; xindex++)
                                        {
                                                MCU_buffer[blkn] = coef->dummy_buffer[blkn];
                                                MCU_buffer[blkn][0][0] = MCU_buffer[blkn - 1][0][0];
                                                blkn++;
                                        }
                                }
                        }
                        /* Try to write the MCU. */
                        if (!(*cinfo->entropy->encode_mcu)(cinfo, MCU_buffer))
                        {
                                /* Suspension forced; update state counters and exit */
                                coef->MCU_vert_offset = yoffset;
                                coef->mcu_ctr = MCU_col_num;
                                return FALSE;
                        }
                }
                /* Completed an MCU row, but perhaps not an iMCU row */
                coef->mcu_ctr = 0;
        }
        /* Completed the iMCU row, advance counters for next one */
        coef->iMCU_row_num++;
        start_iMCU_row(cinfo);
        return TRUE;
}

/*
 * Initialize coefficient buffer controller.
 *
 * Each passed coefficient array must be the right size for that
 * coefficient: width_in_blocks wide and height_in_blocks high,
 * with unitheight at least v_samp_factor.
 */

LOCAL(void)
transencode_coef_controller(j_compress_ptr cinfo, jvirt_barray_ptr* coef_arrays)
{
        my_coef_ptr coef;
        JBLOCKROW buffer;
        int i;

        coef = (my_coef_ptr)(*cinfo->mem->alloc_small)(
                (j_common_ptr)cinfo, JPOOL_IMAGE, SIZEOF(my_coef_controller));
        cinfo->coef = (struct jpeg_c_coef_controller*)coef;
        coef->pub.start_pass = start_pass_coef;
        coef->pub.compress_data = compress_output;

        /* Save pointer to virtual arrays */
        coef->whole_image = coef_arrays;

        /* Allocate and pre-zero space for dummy DCT blocks. */
        buffer = (JBLOCKROW)(*cinfo->mem->alloc_large)(
                (j_common_ptr)cinfo, JPOOL_IMAGE, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
        jzero_far((void FAR*)buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));
        for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++)
        {
                coef->dummy_buffer[i] = buffer + i;
        }
}