jcmarker.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"

typedef enum { /* JPEG marker codes */
                           M_SOF0 = 0xc0,
                           M_SOF1 = 0xc1,
                           M_SOF2 = 0xc2,
                           M_SOF3 = 0xc3,

                           M_SOF5 = 0xc5,
                           M_SOF6 = 0xc6,
                           M_SOF7 = 0xc7,

                           M_JPG = 0xc8,
                           M_SOF9 = 0xc9,
                           M_SOF10 = 0xca,
                           M_SOF11 = 0xcb,

                           M_SOF13 = 0xcd,
                           M_SOF14 = 0xce,
                           M_SOF15 = 0xcf,

                           M_DHT = 0xc4,

                           M_DAC = 0xcc,

                           M_RST0 = 0xd0,
                           M_RST1 = 0xd1,
                           M_RST2 = 0xd2,
                           M_RST3 = 0xd3,
                           M_RST4 = 0xd4,
                           M_RST5 = 0xd5,
                           M_RST6 = 0xd6,
                           M_RST7 = 0xd7,

                           M_SOI = 0xd8,
                           M_EOI = 0xd9,
                           M_SOS = 0xda,
                           M_DQT = 0xdb,
                           M_DNL = 0xdc,
                           M_DRI = 0xdd,
                           M_DHP = 0xde,
                           M_EXP = 0xdf,

                           M_APP0 = 0xe0,
                           M_APP1 = 0xe1,
                           M_APP2 = 0xe2,
                           M_APP3 = 0xe3,
                           M_APP4 = 0xe4,
                           M_APP5 = 0xe5,
                           M_APP6 = 0xe6,
                           M_APP7 = 0xe7,
                           M_APP8 = 0xe8,
                           M_APP9 = 0xe9,
                           M_APP10 = 0xea,
                           M_APP11 = 0xeb,
                           M_APP12 = 0xec,
                           M_APP13 = 0xed,
                           M_APP14 = 0xee,
                           M_APP15 = 0xef,

                           M_JPG0 = 0xf0,
                           M_JPG13 = 0xfd,
                           M_COM = 0xfe,

                           M_TEM = 0x01,

                           M_ERROR = 0x100
} JPEG_MARKER;

/* Private state */

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

        unsigned int
                last_restart_interval; /* last DRI value emitted; 0 after SOI */
} my_marker_writer;

typedef my_marker_writer* my_marker_ptr;

/*
 * Basic output routines.
 *
 * Note that we do not support suspension while writing a marker.
 * Therefore, an application using suspension must ensure that there is
 * enough buffer space for the initial markers (typ. 600-700 bytes) before
 * calling jpeg_start_compress, and enough space to write the trailing EOI
 * (a few bytes) before calling jpeg_finish_compress.  Multipass compression
 * modes are not supported at all with suspension, so those two are the only
 * points where markers will be written.
 */

LOCAL(void)
emit_byte(j_compress_ptr cinfo, int val)
/* Emit a byte */
{
        struct jpeg_destination_mgr* dest = cinfo->dest;

        *(dest->next_output_byte)++ = (JOCTET)val;
        if (--dest->free_in_buffer == 0)
        {
                if (!(*dest->empty_output_buffer)(cinfo))
                        ERREXIT(cinfo, JERR_CANT_SUSPEND);
        }
}

LOCAL(void)
emit_marker(j_compress_ptr cinfo, JPEG_MARKER mark)
/* Emit a marker code */
{
        emit_byte(cinfo, 0xFF);
        emit_byte(cinfo, (int)mark);
}

LOCAL(void)
emit_2bytes(j_compress_ptr cinfo, int value)
/* Emit a 2-byte integer; these are always MSB first in JPEG files */
{
        emit_byte(cinfo, (value >> 8) & 0xFF);
        emit_byte(cinfo, value & 0xFF);
}

/*
 * Routines to write specific marker types.
 */

LOCAL(int)
emit_dqt(j_compress_ptr cinfo, int index)
/* Emit a DQT marker */
/* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
{
        JQUANT_TBL* qtbl = cinfo->quant_tbl_ptrs[index];
        int prec;
        int i;

        if (qtbl == nullptr) ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);

        prec = 0;
        for (i = 0; i < DCTSIZE2; i++)
        {
                if (qtbl->quantval[i] > 255) prec = 1;
        }

        if (!qtbl->sent_table)
        {
                emit_marker(cinfo, M_DQT);

                emit_2bytes(cinfo, prec ? DCTSIZE2 * 2 + 1 + 2 : DCTSIZE2 + 1 + 2);

                emit_byte(cinfo, index + (prec << 4));

                for (i = 0; i < DCTSIZE2; i++)
                {
                        /* The table entries must be emitted in zigzag order. */
                        unsigned int qval = qtbl->quantval[jpeg_natural_order[i]];
                        if (prec) emit_byte(cinfo, (int)(qval >> 8));
                        emit_byte(cinfo, (int)(qval & 0xFF));
                }

                qtbl->sent_table = TRUE;
        }

        return prec;
}

LOCAL(void)
emit_dht(j_compress_ptr cinfo, int index, boolean is_ac)
/* Emit a DHT marker */
{
        JHUFF_TBL* htbl;
        int length, i;

        if (is_ac)
        {
                htbl = cinfo->ac_huff_tbl_ptrs[index];
                index += 0x10; /* output index has AC bit set */
        }
        else
        {
                htbl = cinfo->dc_huff_tbl_ptrs[index];
        }

        if (htbl == nullptr) ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);

        if (!htbl->sent_table)
        {
                emit_marker(cinfo, M_DHT);

                length = 0;
                for (i = 1; i <= 16; i++) length += htbl->bits[i];

                emit_2bytes(cinfo, length + 2 + 1 + 16);
                emit_byte(cinfo, index);

                for (i = 1; i <= 16; i++) emit_byte(cinfo, htbl->bits[i]);

                for (i = 0; i < length; i++) emit_byte(cinfo, htbl->huffval[i]);

                htbl->sent_table = TRUE;
        }
}

LOCAL(void)
emit_dac(j_compress_ptr)
/* Emit a DAC marker */
/* Since the useful info is so small, we want to emit all the tables in */
/* one DAC marker.  Therefore this routine does its own scan of the table. */
{
#ifdef C_ARITH_CODING_SUPPORTED
        char dc_in_use[NUM_ARITH_TBLS];
        char ac_in_use[NUM_ARITH_TBLS];
        int length, i;
        jpeg_component_info* compptr;

        for (i = 0; i < NUM_ARITH_TBLS; i++) dc_in_use[i] = ac_in_use[i] = 0;

        for (i = 0; i < cinfo->comps_in_scan; i++)
        {
                compptr = cinfo->cur_comp_info[i];
                dc_in_use[compptr->dc_tbl_no] = 1;
                ac_in_use[compptr->ac_tbl_no] = 1;
        }

        length = 0;
        for (i = 0; i < NUM_ARITH_TBLS; i++) length += dc_in_use[i] + ac_in_use[i];

        emit_marker(cinfo, M_DAC);

        emit_2bytes(cinfo, length * 2 + 2);

        for (i = 0; i < NUM_ARITH_TBLS; i++)
        {
                if (dc_in_use[i])
                {
                        emit_byte(cinfo, i);
                        emit_byte(
                                cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i] << 4));
                }
                if (ac_in_use[i])
                {
                        emit_byte(cinfo, i + 0x10);
                        emit_byte(cinfo, cinfo->arith_ac_K[i]);
                }
        }
#endif /* C_ARITH_CODING_SUPPORTED */
}

LOCAL(void)
emit_dri(j_compress_ptr cinfo)
/* Emit a DRI marker */
{
        emit_marker(cinfo, M_DRI);

        emit_2bytes(cinfo, 4); /* fixed length */

        emit_2bytes(cinfo, (int)cinfo->restart_interval);
}

LOCAL(void)
emit_sof(j_compress_ptr cinfo, JPEG_MARKER code)
/* Emit a SOF marker */
{
        int ci;
        jpeg_component_info* compptr;

        emit_marker(cinfo, code);

        emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */

        /* Make sure image isn't bigger than SOF field can handle */
        if ((long)cinfo->image_height > 65535L || (long)cinfo->image_width > 65535L)
                ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int)65535);

        emit_byte(cinfo, cinfo->data_precision);
        emit_2bytes(cinfo, (int)cinfo->image_height);
        emit_2bytes(cinfo, (int)cinfo->image_width);

        emit_byte(cinfo, cinfo->num_components);

        for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
                 ci++, compptr++)
        {
                emit_byte(cinfo, compptr->component_id);
                emit_byte(
                        cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor);
                emit_byte(cinfo, compptr->quant_tbl_no);
        }
}

LOCAL(void)
emit_sos(j_compress_ptr cinfo)
/* Emit a SOS marker */
{
        int i, td, ta;
        jpeg_component_info* compptr;

        emit_marker(cinfo, M_SOS);

        emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */

        emit_byte(cinfo, cinfo->comps_in_scan);

        for (i = 0; i < cinfo->comps_in_scan; i++)
        {
                compptr = cinfo->cur_comp_info[i];
                emit_byte(cinfo, compptr->component_id);
                td = compptr->dc_tbl_no;
                ta = compptr->ac_tbl_no;
                if (cinfo->progressive_mode)
                {
                        /* Progressive mode: only DC or only AC tables are used in one scan;
                         * furthermore, Huffman coding of DC refinement uses no table at
                         * all.
                         * We emit 0 for unused field(s); this is recommended by the P&M
                         * text
                         * but does not seem to be specified in the standard.
                         */
                        if (cinfo->Ss == 0)
                        {
                                ta = 0; /* DC scan */
                                if (cinfo->Ah != 0 && !cinfo->arith_code)
                                        td = 0; /* no DC table either */
                        }
                        else
                        {
                                td = 0; /* AC scan */
                        }
                }
                emit_byte(cinfo, (td << 4) + ta);
        }

        emit_byte(cinfo, cinfo->Ss);
        emit_byte(cinfo, cinfo->Se);
        emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al);
}

LOCAL(void)
emit_jfif_app0(j_compress_ptr cinfo)
/* Emit a JFIF-compliant APP0 marker */
{
        /*
         * Length of APP0 block (2 bytes)
         * Block ID                     (4 bytes - ASCII "JFIF")
         * Zero byte                    (1 byte to terminate the ID string)
         * Version Major, Minor (2 bytes - major first)
         * Units                        (1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
         * Xdpu                 (2 bytes - dots per unit horizontal)
         * Ydpu                 (2 bytes - dots per unit vertical)
         * Thumbnail X size             (1 byte)
         * Thumbnail Y size             (1 byte)
         */

        emit_marker(cinfo, M_APP0);

        emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */

        emit_byte(cinfo, 0x4A); /* Identifier: ASCII "JFIF" */
        emit_byte(cinfo, 0x46);
        emit_byte(cinfo, 0x49);
        emit_byte(cinfo, 0x46);
        emit_byte(cinfo, 0);
        emit_byte(cinfo, cinfo->JFIF_major_version); /* Version fields */
        emit_byte(cinfo, cinfo->JFIF_minor_version);
        emit_byte(cinfo, cinfo->density_unit); /* Pixel size information */
        emit_2bytes(cinfo, (int)cinfo->X_density);
        emit_2bytes(cinfo, (int)cinfo->Y_density);
        emit_byte(cinfo, 0); /* No thumbnail image */
        emit_byte(cinfo, 0);
}

LOCAL(void)
emit_adobe_app14(j_compress_ptr cinfo)
/* Emit an Adobe APP14 marker */
{
        /*
         * Length of APP14 block        (2 bytes)
         * Block ID                     (5 bytes - ASCII "Adobe")
         * Version Number               (2 bytes - currently 100)
         * Flags0                       (2 bytes - currently 0)
         * Flags1                       (2 bytes - currently 0)
         * Color transform              (1 byte)
         *
         * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
         * now in circulation seem to use Version = 100, so that's what we write.
         *
         * We write the color transform byte as 1 if the JPEG color space is
         * YCbCr, 2 if it's YCCK, 0 otherwise.  Adobe's definition has to do with
         * whether the encoder performed a transformation, which is pretty useless.
         */

        emit_marker(cinfo, M_APP14);

        emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */

        emit_byte(cinfo, 0x41); /* Identifier: ASCII "Adobe" */
        emit_byte(cinfo, 0x64);
        emit_byte(cinfo, 0x6F);
        emit_byte(cinfo, 0x62);
        emit_byte(cinfo, 0x65);
        emit_2bytes(cinfo, 100); /* Version */
        emit_2bytes(cinfo, 0); /* Flags0 */
        emit_2bytes(cinfo, 0); /* Flags1 */
        switch (cinfo->jpeg_color_space)
        {
                case JCS_YCbCr:
                        emit_byte(cinfo, 1); /* Color transform = 1 */
                        break;
                case JCS_YCCK:
                        emit_byte(cinfo, 2); /* Color transform = 2 */
                        break;
                default:
                        emit_byte(cinfo, 0); /* Color transform = 0 */
                        break;
        }
}

/*
 * These routines allow writing an arbitrary marker with parameters.
 * The only intended use is to emit COM or APPn markers after calling
 * write_file_header and before calling write_frame_header.
 * Other uses are not guaranteed to produce desirable results.
 * Counting the parameter bytes properly is the caller's responsibility.
 */

METHODDEF(void)
write_marker_header(j_compress_ptr cinfo, int marker, unsigned int datalen)
/* Emit an arbitrary marker header */
{
        if (datalen > (unsigned int)65533) /* safety check */
                ERREXIT(cinfo, JERR_BAD_LENGTH);

        emit_marker(cinfo, (JPEG_MARKER)marker);

        emit_2bytes(cinfo, (int)(datalen + 2)); /* total length */
}

METHODDEF(void)
write_marker_byte(j_compress_ptr cinfo, int val)
/* Emit one byte of marker parameters following write_marker_header */
{
        emit_byte(cinfo, val);
}

/*
 * Write datastream header.
 * This consists of an SOI and optional APPn markers.
 * We recommend use of the JFIF marker, but not the Adobe marker,
 * when using YCbCr or grayscale data.  The JFIF marker should NOT
 * be used for any other JPEG colorspace.  The Adobe marker is helpful
 * to distinguish RGB, CMYK, and YCCK colorspaces.
 * Note that an application can write additional header markers after
 * jpeg_start_compress returns.
 */

METHODDEF(void)
write_file_header(j_compress_ptr cinfo)
{
        my_marker_ptr marker = (my_marker_ptr)cinfo->marker;

        emit_marker(cinfo, M_SOI); /* first the SOI */

        /* SOI is defined to reset restart interval to 0 */
        marker->last_restart_interval = 0;

        if (cinfo->write_JFIF_header) /* next an optional JFIF APP0 */
                emit_jfif_app0(cinfo);
        if (cinfo->write_Adobe_marker) /* next an optional Adobe APP14 */
                emit_adobe_app14(cinfo);
}

/*
 * Write frame header.
 * This consists of DQT and SOFn markers.
 * Note that we do not emit the SOF until we have emitted the DQT(s).
 * This avoids compatibility problems with incorrect implementations that
 * try to error-check the quant table numbers as soon as they see the SOF.
 */

METHODDEF(void)
write_frame_header(j_compress_ptr cinfo)
{
        int ci, prec;
        boolean is_baseline;
        jpeg_component_info* compptr;

        /* Emit DQT for each quantization table.
         * Note that emit_dqt() suppresses any duplicate tables.
         */
        prec = 0;
        for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
                 ci++, compptr++)
        {
                prec += emit_dqt(cinfo, compptr->quant_tbl_no);
        }
        /* now prec is nonzero iff there are any 16-bit quant tables. */

        /* Check for a non-baseline specification.
         * Note we assume that Huffman table numbers won't be changed later.
         */
        if (cinfo->arith_code || cinfo->progressive_mode ||
                cinfo->data_precision != 8)
        {
                is_baseline = FALSE;
        }
        else
        {
                is_baseline = TRUE;
                for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
                         ci++, compptr++)
                {
                        if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)
                                is_baseline = FALSE;
                }
                if (prec && is_baseline)
                {
                        is_baseline = FALSE;
                        /* If it's baseline except for quantizer size, warn the user */
                        TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);
                }
        }

        /* Emit the proper SOF marker */
        if (cinfo->arith_code)
        {
                emit_sof(cinfo, M_SOF9); /* SOF code for arithmetic coding */
        }
        else
        {
                if (cinfo->progressive_mode)
                        emit_sof(cinfo, M_SOF2); /* SOF code for progressive Huffman */
                else if (is_baseline)
                        emit_sof(cinfo, M_SOF0); /* SOF code for baseline implementation */
                else
                        emit_sof(
                                cinfo, M_SOF1); /* SOF code for non-baseline Huffman file */
        }
}

/*
 * Write scan header.
 * This consists of DHT or DAC markers, optional DRI, and SOS.
 * Compressed data will be written following the SOS.
 */

METHODDEF(void)
write_scan_header(j_compress_ptr cinfo)
{
        my_marker_ptr marker = (my_marker_ptr)cinfo->marker;
        int i;
        jpeg_component_info* compptr;

        if (cinfo->arith_code)
        {
                /* Emit arith conditioning info.  We may have some duplication
                 * if the file has multiple scans, but it's so small it's hardly
                 * worth worrying about.
                 */
                emit_dac(cinfo);
        }
        else
        {
                /* Emit Huffman tables.
                 * Note that emit_dht() suppresses any duplicate tables.
                 */
                for (i = 0; i < cinfo->comps_in_scan; i++)
                {
                        compptr = cinfo->cur_comp_info[i];
                        if (cinfo->progressive_mode)
                        {
                                /* Progressive mode: only DC or only AC tables are used in one
                                 * scan */
                                if (cinfo->Ss == 0)
                                {
                                        if (cinfo->Ah ==
                                                0) /* DC needs no table for refinement scan */
                                                emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
                                }
                                else
                                {
                                        emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
                                }
                        }
                        else
                        {
                                /* Sequential mode: need both DC and AC tables */
                                emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
                                emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
                        }
                }
        }

        /* Emit DRI if required --- note that DRI value could change for each scan.
         * We avoid wasting space with unnecessary DRIs, however.
         */
        if (cinfo->restart_interval != marker->last_restart_interval)
        {
                emit_dri(cinfo);
                marker->last_restart_interval = cinfo->restart_interval;
        }

        emit_sos(cinfo);
}

/*
 * Write datastream trailer.
 */

METHODDEF(void)
write_file_trailer(j_compress_ptr cinfo) { emit_marker(cinfo, M_EOI); }
/*
 * Write an abbreviated table-specification datastream.
 * This consists of SOI, DQT and DHT tables, and EOI.
 * Any table that is defined and not marked sent_table = TRUE will be
 * emitted.  Note that all tables will be marked sent_table = TRUE at exit.
 */

METHODDEF(void)
write_tables_only(j_compress_ptr cinfo)
{
        int i;

        emit_marker(cinfo, M_SOI);

        for (i = 0; i < NUM_QUANT_TBLS; i++)
        {
                if (cinfo->quant_tbl_ptrs[i] != nullptr) (void)emit_dqt(cinfo, i);
        }

        if (!cinfo->arith_code)
        {
                for (i = 0; i < NUM_HUFF_TBLS; i++)
                {
                        if (cinfo->dc_huff_tbl_ptrs[i] != nullptr)
                                emit_dht(cinfo, i, FALSE);
                        if (cinfo->ac_huff_tbl_ptrs[i] != nullptr) emit_dht(cinfo, i, TRUE);
                }
        }

        emit_marker(cinfo, M_EOI);
}

/*
 * Initialize the marker writer module.
 */

GLOBAL(void)
jinit_marker_writer(j_compress_ptr cinfo)
{
        my_marker_ptr marker;

        /* Create the subobject */
        marker = (my_marker_ptr)(*cinfo->mem->alloc_small)(
                (j_common_ptr)cinfo, JPOOL_IMAGE, SIZEOF(my_marker_writer));
        cinfo->marker = (struct jpeg_marker_writer*)marker;
        /* Initialize method pointers */
        marker->pub.write_file_header = write_file_header;
        marker->pub.write_frame_header = write_frame_header;
        marker->pub.write_scan_header = write_scan_header;
        marker->pub.write_file_trailer = write_file_trailer;
        marker->pub.write_tables_only = write_tables_only;
        marker->pub.write_marker_header = write_marker_header;
        marker->pub.write_marker_byte = write_marker_byte;
        /* Initialize private state */
        marker->last_restart_interval = 0;
}