jdinput.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_input_controller pub; /* public fields */

        boolean inheaders; /* TRUE until first SOS is reached */
} my_input_controller;

typedef my_input_controller* my_inputctl_ptr;

/* Forward declarations */
METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo));

/*
 * Routines to calculate various quantities related to the size of the image.
 */

LOCAL(void)
initial_setup(j_decompress_ptr cinfo)
/* Called once, when first SOS marker is reached */
{
        int ci;
        jpeg_component_info* compptr;

        /* Make sure image isn't bigger than I can handle */
        if ((long)cinfo->image_height > (long)JPEG_MAX_DIMENSION ||
                (long)cinfo->image_width > (long)JPEG_MAX_DIMENSION)
                ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int)JPEG_MAX_DIMENSION);

        /* For now, precision must match compiled-in value... */
        if (cinfo->data_precision != BITS_IN_JSAMPLE)
                ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision);

        /* Check that number of components won't exceed internal array sizes */
        if (cinfo->num_components > MAX_COMPONENTS)
                ERREXIT2(
                        cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, MAX_COMPONENTS);

        /* Compute maximum sampling factors; check factor validity */
        cinfo->max_h_samp_factor = 1;
        cinfo->max_v_samp_factor = 1;
        for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
                 ci++, compptr++)
        {
                if (compptr->h_samp_factor <= 0 ||
                        compptr->h_samp_factor > MAX_SAMP_FACTOR ||
                        compptr->v_samp_factor <= 0 ||
                        compptr->v_samp_factor > MAX_SAMP_FACTOR)
                        ERREXIT(cinfo, JERR_BAD_SAMPLING);
                cinfo->max_h_samp_factor =
                        MAX(cinfo->max_h_samp_factor, compptr->h_samp_factor);
                cinfo->max_v_samp_factor =
                        MAX(cinfo->max_v_samp_factor, compptr->v_samp_factor);
        }

        /* We initialize DCT_scaled_size and min_DCT_scaled_size to DCTSIZE.
         * In the full decompressor, this will be overridden by jdmaster.c;
         * but in the transcoder, jdmaster.c is not used, so we must do it here.
         */
        cinfo->min_DCT_scaled_size = DCTSIZE;

        /* Compute dimensions of components */
        for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
                 ci++, compptr++)
        {
                compptr->DCT_scaled_size = DCTSIZE;
                /* Size in DCT blocks */
                compptr->width_in_blocks = (JDIMENSION)jdiv_round_up(
                        (long)cinfo->image_width * (long)compptr->h_samp_factor,
                        (long)(cinfo->max_h_samp_factor * DCTSIZE));
                compptr->height_in_blocks = (JDIMENSION)jdiv_round_up(
                        (long)cinfo->image_height * (long)compptr->v_samp_factor,
                        (long)(cinfo->max_v_samp_factor * DCTSIZE));
                /* downsampled_width and downsampled_height will also be overridden by
                 * jdmaster.c if we are doing full decompression.  The transcoder
                 * library
                 * doesn't use these values, but the calling application might.
                 */
                /* Size in samples */
                compptr->downsampled_width = (JDIMENSION)jdiv_round_up(
                        (long)cinfo->image_width * (long)compptr->h_samp_factor,
                        (long)cinfo->max_h_samp_factor);
                compptr->downsampled_height = (JDIMENSION)jdiv_round_up(
                        (long)cinfo->image_height * (long)compptr->v_samp_factor,
                        (long)cinfo->max_v_samp_factor);
                /* Mark component needed, until color conversion says otherwise */
                compptr->component_needed = TRUE;
                /* Mark no quantization table yet saved for component */
                compptr->quant_table = nullptr;
        }

        /* Compute number of fully interleaved MCU rows. */
        cinfo->total_iMCU_rows = (JDIMENSION)jdiv_round_up(
                (long)cinfo->image_height, (long)(cinfo->max_v_samp_factor * DCTSIZE));

        /* Decide whether file contains multiple scans */
        if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode)
                cinfo->inputctl->has_multiple_scans = TRUE;
        else
                cinfo->inputctl->has_multiple_scans = FALSE;
}

LOCAL(void)
per_scan_setup(j_decompress_ptr cinfo)
/* Do computations that are needed before processing a JPEG scan */
/* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */
{
        int ci, mcublks, tmp;
        jpeg_component_info* compptr;

        if (cinfo->comps_in_scan == 1)
        {
                /* Noninterleaved (single-component) scan */
                compptr = cinfo->cur_comp_info[0];

                /* Overall image size in MCUs */
                cinfo->MCUs_per_row = compptr->width_in_blocks;
                cinfo->MCU_rows_in_scan = compptr->height_in_blocks;

                /* For noninterleaved scan, always one block per MCU */
                compptr->MCU_width = 1;
                compptr->MCU_height = 1;
                compptr->MCU_blocks = 1;
                compptr->MCU_sample_width = compptr->DCT_scaled_size;
                compptr->last_col_width = 1;
                /* For noninterleaved scans, it is convenient to define last_row_height
                 * as the number of block rows present in the last iMCU row.
                 */
                tmp = (int)(compptr->height_in_blocks % compptr->v_samp_factor);
                if (tmp == 0) tmp = compptr->v_samp_factor;
                compptr->last_row_height = tmp;

                /* Prepare array describing MCU composition */
                cinfo->blocks_in_MCU = 1;
                cinfo->MCU_membership[0] = 0;
        }
        else
        {
                /* Interleaved (multi-component) scan */
                if (cinfo->comps_in_scan <= 0 ||
                        cinfo->comps_in_scan > MAX_COMPS_IN_SCAN)
                        ERREXIT2(
                                cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan,
                                MAX_COMPS_IN_SCAN);

                /* Overall image size in MCUs */
                cinfo->MCUs_per_row = (JDIMENSION)jdiv_round_up(
                        (long)cinfo->image_width,
                        (long)(cinfo->max_h_samp_factor * DCTSIZE));
                cinfo->MCU_rows_in_scan = (JDIMENSION)jdiv_round_up(
                        (long)cinfo->image_height,
                        (long)(cinfo->max_v_samp_factor * DCTSIZE));

                cinfo->blocks_in_MCU = 0;

                for (ci = 0; ci < cinfo->comps_in_scan; ci++)
                {
                        compptr = cinfo->cur_comp_info[ci];
                        /* Sampling factors give # of blocks of component in each MCU */
                        compptr->MCU_width = compptr->h_samp_factor;
                        compptr->MCU_height = compptr->v_samp_factor;
                        compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height;
                        compptr->MCU_sample_width =
                                compptr->MCU_width * compptr->DCT_scaled_size;
                        /* Figure number of non-dummy blocks in last MCU column & row */
                        tmp = (int)(compptr->width_in_blocks % compptr->MCU_width);
                        if (tmp == 0) tmp = compptr->MCU_width;
                        compptr->last_col_width = tmp;
                        tmp = (int)(compptr->height_in_blocks % compptr->MCU_height);
                        if (tmp == 0) tmp = compptr->MCU_height;
                        compptr->last_row_height = tmp;
                        /* Prepare array describing MCU composition */
                        mcublks = compptr->MCU_blocks;
                        if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU)
                                ERREXIT(cinfo, JERR_BAD_MCU_SIZE);
                        while (mcublks-- > 0)
                        {
                                cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci;
                        }
                }
        }
}

/*
 * Save away a copy of the Q-table referenced by each component present
 * in the current scan, unless already saved during a prior scan.
 *
 * In a multiple-scan JPEG file, the encoder could assign different components
 * the same Q-table slot number, but change table definitions between scans
 * so that each component uses a different Q-table.  (The IJG encoder is not
 * currently capable of doing this, but other encoders might.)  Since we want
 * to be able to dequantize all the components at the end of the file, this
 * means that we have to save away the table actually used for each component.
 * We do this by copying the table at the start of the first scan containing
 * the component.
 * The JPEG spec prohibits the encoder from changing the contents of a Q-table
 * slot between scans of a component using that slot.  If the encoder does so
 * anyway, this decoder will simply use the Q-table values that were current
 * at the start of the first scan for the component.
 *
 * The decompressor output side looks only at the saved quant tables,
 * not at the current Q-table slots.
 */

LOCAL(void)
latch_quant_tables(j_decompress_ptr cinfo)
{
        int ci, qtblno;
        jpeg_component_info* compptr;
        JQUANT_TBL* qtbl;

        for (ci = 0; ci < cinfo->comps_in_scan; ci++)
        {
                compptr = cinfo->cur_comp_info[ci];
                /* No work if we already saved Q-table for this component */
                if (compptr->quant_table != nullptr) continue;
                /* Make sure specified quantization table is present */
                qtblno = compptr->quant_tbl_no;
                if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
                        cinfo->quant_tbl_ptrs[qtblno] == nullptr)
                        ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
                /* OK, save away the quantization table */
                qtbl = (JQUANT_TBL*)(*cinfo->mem->alloc_small)(
                        (j_common_ptr)cinfo, JPOOL_IMAGE, SIZEOF(JQUANT_TBL));
                MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL));
                compptr->quant_table = qtbl;
        }
}

/*
 * Initialize the input modules to read a scan of compressed data.
 * The first call to this is done by jdmaster.c after initializing
 * the entire decompressor (during jpeg_start_decompress).
 * Subsequent calls come from consume_markers, below.
 */

METHODDEF(void)
start_input_pass(j_decompress_ptr cinfo)
{
        per_scan_setup(cinfo);
        latch_quant_tables(cinfo);
        (*cinfo->entropy->start_pass)(cinfo);
        (*cinfo->coef->start_input_pass)(cinfo);
        cinfo->inputctl->consume_input = cinfo->coef->consume_data;
}

/*
 * Finish up after inputting a compressed-data scan.
 * This is called by the coefficient controller after it's read all
 * the expected data of the scan.
 */

METHODDEF(void)
finish_input_pass(j_decompress_ptr cinfo)
{
        cinfo->inputctl->consume_input = consume_markers;
}

/*
 * Read JPEG markers before, between, or after compressed-data scans.
 * Change state as necessary when a new scan is reached.
 * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
 *
 * The consume_input method pointer points either here or to the
 * coefficient controller's consume_data routine, depending on whether
 * we are reading a compressed data segment or inter-segment markers.
 */

METHODDEF(int)
consume_markers(j_decompress_ptr cinfo)
{
        my_inputctl_ptr inputctl = (my_inputctl_ptr)cinfo->inputctl;
        int val;

        if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */
                return JPEG_REACHED_EOI;

        val = (*cinfo->marker->read_markers)(cinfo);

        switch (val)
        {
                case JPEG_REACHED_SOS: /* Found SOS */
                        if (inputctl->inheaders)
                        { /* 1st SOS */
                                initial_setup(cinfo);
                                inputctl->inheaders = FALSE;
                                /* Note: start_input_pass must be called by jdmaster.c
                                 * before any more input can be consumed.  jdapimin.c is
                                 * responsible for enforcing this sequencing.
                                 */
                        }
                        else
                        { /* 2nd or later SOS marker */
                                if (!inputctl->pub.has_multiple_scans)
                                        ERREXIT(
                                                cinfo,
                                                JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */
                                start_input_pass(cinfo);
                        }
                        break;
                case JPEG_REACHED_EOI: /* Found EOI */
                        inputctl->pub.eoi_reached = TRUE;
                        if (inputctl->inheaders)
                        { /* Tables-only datastream, apparently */
                                if (cinfo->marker->saw_SOF) ERREXIT(cinfo, JERR_SOF_NO_SOS);
                        }
                        else
                        {
                                /* Prevent infinite loop in coef ctlr's decompress_data routine
                                 * if user set output_scan_number larger than number of scans.
                                 */
                                if (cinfo->output_scan_number > cinfo->input_scan_number)
                                        cinfo->output_scan_number = cinfo->input_scan_number;
                        }
                        break;
                case JPEG_SUSPENDED:
                        break;
        }

        return val;
}

/*
 * Reset state to begin a fresh datastream.
 */

METHODDEF(void)
reset_input_controller(j_decompress_ptr cinfo)
{
        my_inputctl_ptr inputctl = (my_inputctl_ptr)cinfo->inputctl;

        inputctl->pub.consume_input = consume_markers;
        inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
        inputctl->pub.eoi_reached = FALSE;
        inputctl->inheaders = TRUE;
        /* Reset other modules */
        (*cinfo->err->reset_error_mgr)((j_common_ptr)cinfo);
        (*cinfo->marker->reset_marker_reader)(cinfo);
        /* Reset progression state -- would be cleaner if entropy decoder did this
         */
        cinfo->coef_bits = nullptr;
}

/*
 * Initialize the input controller module.
 * This is called only once, when the decompression object is created.
 */

GLOBAL(void)
jinit_input_controller(j_decompress_ptr cinfo)
{
        my_inputctl_ptr inputctl;

        /* Create subobject in permanent pool */
        inputctl = (my_inputctl_ptr)(*cinfo->mem->alloc_small)(
                (j_common_ptr)cinfo, JPOOL_PERMANENT, SIZEOF(my_input_controller));
        cinfo->inputctl = (struct jpeg_input_controller*)inputctl;
        /* Initialize method pointers */
        inputctl->pub.consume_input = consume_markers;
        inputctl->pub.reset_input_controller = reset_input_controller;
        inputctl->pub.start_input_pass = start_input_pass;
        inputctl->pub.finish_input_pass = finish_input_pass;
        /* Initialize state: can't use reset_input_controller since we don't
         * want to try to reset other modules yet.
         */
        inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */
        inputctl->pub.eoi_reached = FALSE;
        inputctl->inheaders = TRUE;
}