JPEG_band.cpp

/*
* Copyright (c) 2002-2012, California Institute of Technology.
* All rights reserved.  Based on Government Sponsored Research under contracts NAS7-1407 and/or NAS7-03001.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
*   1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
*   2. Redistributions in binary form must reproduce the above copyright notice,
*      this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
*   3. Neither the name of the California Institute of Technology (Caltech), its operating division the Jet Propulsion Laboratory (JPL),
*      the National Aeronautics and Space Administration (NASA), nor the names of its contributors may be used to
*      endorse or promote products derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE CALIFORNIA INSTITUTE OF TECHNOLOGY BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Copyright 2014-2015 Esri
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

/*
 * JPEG band
 * JPEG page compression and decompression functions, gets compiled twice
 * once directly and once through inclusion from JPEG12_band.cpp
 * LIBJPEG_12_H is defined if both 8 and 12 bit JPEG will be supported
 * JPEG12_ON    is defined for the 12 bit versions
 *
 * The MRF JPEG codec implements the Zen (Zero ENhanced) JPEG extension
 * This extension, when supported by the decompressor, preserves the zero or non-zero state of all pixels
 * which allows zero pixels to be used as a non-data mask
 * Clients which don't support the Zen extension will read it as a normal JPEG
 *
 * On page writes, a mask of all fully zero pixels is built
 * If the mask has some zero pixels, it is written in a JPEG APP3 "Zen" marker
 * If the mask has no zero pixels, a zero length APP3 marker is inserted
 * 
 * On page reads, after the JPEG decompression, if a mask or a zero length APP3 marker is detected, 
 * the masked pixels with value of zero are set to 1 while the non-masked ones are set to zero
 * 
 */

#include "marfa.h"
#include <setjmp.h>

CPL_C_START
#include <jpeglib.h>
#include <jerror.h>
CPL_C_END

#define PACKER
#include "BitMask2D.h"
#include "Packer_RLE.h"

CPL_CVSID("$Id$")

NAMESPACE_MRF_START

typedef BitMap2D<> BitMask;

// Values for mask_state flag

enum { NO_MASK = 0, MASK_LOADED, MASK_FULL };

extern char CHUNK_NAME[];
extern size_t CHUNK_NAME_SIZE;

typedef struct MRFJPEGStruct
{
    jmp_buf     setjmpBuffer;
    BitMask *mask;
    int mask_state;

    MRFJPEGStruct()
    {
        memset(&setjmpBuffer, 0, sizeof(setjmpBuffer));
        mask = nullptr;
        mask_state = NO_MASK;
    }
} MRFJPEGErrorStruct;

/**
*\brief Called when jpeg wants to report a warning
* msgLevel can be:
* -1 Corrupt data
* 0 always display
* 1... Trace level
*/

static void emitMessage(j_common_ptr cinfo, int msgLevel)
{
    if (msgLevel > 0) return; // No trace msgs
    // There can be many warnings, just print the first one
    if (cinfo->err->num_warnings++ >1) return;
    char buffer[JMSG_LENGTH_MAX];
    cinfo->err->format_message(cinfo, buffer);
    CPLError(CE_Failure, CPLE_AppDefined, "%s", buffer);
}

static void errorExit(j_common_ptr cinfo)
{
    MRFJPEGStruct* psJPEGStruct = (MRFJPEGStruct* ) cinfo->client_data;
    // format the warning message
    char buffer[JMSG_LENGTH_MAX];

    cinfo->err->format_message(cinfo, buffer);
    CPLError(CE_Failure, CPLE_AppDefined, "%s", buffer);
    // return control to the setjmp point
    longjmp(psJPEGStruct->setjmpBuffer, 1);
}

/**
*\brief Do nothing stub function for JPEG library, called
*/
static void stub_source_dec(j_decompress_ptr /*cinfo*/) {}

/**
*\brief: This function is supposed to do refilling of the input buffer,
* but as we provided everything at the beginning, if it is called, then
* we have an error.
*/
static boolean fill_input_buffer_dec(j_decompress_ptr cinfo)
{
    CPLError(CE_Failure, CPLE_AppDefined, "Invalid JPEG stream");
    cinfo->err->msg_code = JERR_INPUT_EMPTY;
    cinfo->err->error_exit((j_common_ptr)(cinfo));
    return FALSE;
}

/**
*\brief: Do nothing stub function for JPEG library, not called
*/
static void skip_input_data_dec(j_decompress_ptr cinfo, long l) {
    struct jpeg_source_mgr *src = cinfo->src;
    if (l > 0) {
        if (static_cast<size_t>(l) > src->bytes_in_buffer)
            l = static_cast<long>(src->bytes_in_buffer);
        src->bytes_in_buffer -= l;
        src->next_input_byte += l;
    }
}

// Destination should be already set up
static void init_or_terminate_destination(j_compress_ptr /*cinfo*/) {}

// Called if the buffer provided is too small
static boolean empty_output_buffer(j_compress_ptr /*cinfo*/) {
    std::cerr << "JPEG Output buffer empty called\n";
    return FALSE;
}

// Returns the number of zero pixels in the page, as well as clearing those bits in the mask
template<typename T> int update_mask(BitMask &mask, T *src, int nc) {
    int zeros = 0;
    int h = mask.getHeight();
    int w = mask.getWidth();
    for (int y = 0; y < h; y++)
        for (int x = 0; x < w; x++) {
            bool is_zero = true;
            for (int c = 0; c < nc; c++)
                if (*src++ != 0)
                    is_zero = false;
            if (is_zero) {
                zeros++;
                mask.clear(x, y);
            }
        }
    return zeros;
}

/*
*\brief Compress a JPEG page in memory
*
* It handles byte or 12 bit data, grayscale, RGB, YUV, and multispectral
*
* Returns the compressed size in dest.size
*/
#if defined(JPEG12_ON)
CPLErr JPEG_Codec::CompressJPEG12(buf_mgr &dst, buf_mgr &src)
#else
CPLErr JPEG_Codec::CompressJPEG(buf_mgr &dst, buf_mgr &src)
#endif

{
    // The cinfo should stay open and reside in the DS, since it can be left initialized
    // It saves some time because it has the tables initialized
    struct jpeg_compress_struct cinfo;
    MRFJPEGStruct sJPEGStruct;
    struct jpeg_error_mgr sJErr;
    ILSize sz = img.pagesize;

    jpeg_destination_mgr jmgr;
    jmgr.next_output_byte = (JOCTET *)dst.buffer;
    jmgr.free_in_buffer = dst.size;
    jmgr.init_destination = init_or_terminate_destination;
    jmgr.empty_output_buffer = empty_output_buffer;
    jmgr.term_destination = init_or_terminate_destination;

    memset(&cinfo, 0, sizeof(cinfo));

    // Look at the source of this, some interesting tidbits
    cinfo.err = jpeg_std_error(&sJErr);
    sJErr.error_exit = errorExit;
    sJErr.emit_message = emitMessage;
    cinfo.client_data = (void *)&(sJPEGStruct);
    jpeg_create_compress(&cinfo);
    cinfo.dest = &jmgr;

    // The page specific info, size and color spaces
    cinfo.image_width = sz.x;
    cinfo.image_height = sz.y;
    cinfo.input_components = sz.c;
    switch (cinfo.input_components) {
    case 1:cinfo.in_color_space = JCS_GRAYSCALE; break;
    case 3:cinfo.in_color_space = JCS_RGB; break;  // Stored as YCbCr 4:2:0 by default
    default:
        cinfo.in_color_space = JCS_UNKNOWN; // 2, 4-10 bands
    }

    // Set all required fields and overwrite the ones we want to change
    jpeg_set_defaults(&cinfo);

    // Override certain settings
    jpeg_set_quality(&cinfo, img.quality, TRUE);
    cinfo.dct_method = JDCT_FLOAT; // Pretty fast and precise
    cinfo.optimize_coding = optimize; // Set "OPTIMIZE=TRUE" in OPTIONS, default for 12bit

    // Do we explicitly turn off the YCC color and downsampling?

    if (cinfo.in_color_space == JCS_RGB) {
        if (rgb) {  // Stored as RGB
            jpeg_set_colorspace(&cinfo, JCS_RGB);  // Huge files
        }
        else if (sameres) { // YCC, somewhat larger files with improved color spatial detail
            cinfo.comp_info[0].h_samp_factor = 1;
            cinfo.comp_info[0].v_samp_factor = 1;

            // Enabling these lines will make the color components use the same tables as Y, even larger file with slightly better color depth detail
            // cinfo.comp_info[1].quant_tbl_no = 0;
            // cinfo.comp_info[2].quant_tbl_no = 0;

            // cinfo.comp_info[1].dc_tbl_no = 0;
            // cinfo.comp_info[2].dc_tbl_no = 0;

            // cinfo.comp_info[1].ac_tbl_no = 0;
            // cinfo.comp_info[2].ac_tbl_no = 0;
        }
    }

    int linesize = cinfo.image_width * cinfo.input_components * ((cinfo.data_precision == 8) ? 1 : 2);
    JSAMPROW *rowp = (JSAMPROW *)CPLMalloc(sizeof(JSAMPROW)*sz.y);
    if (!rowp) {
        CPLError(CE_Failure, CPLE_AppDefined, "MRF: JPEG compression error");
        jpeg_destroy_compress(&cinfo);
        return CE_Failure;
    }

    for (int i = 0; i < sz.y; i++)
        rowp[i] = (JSAMPROW)(src.buffer + i*linesize);

    if (setjmp(sJPEGStruct.setjmpBuffer)) {
        CPLError(CE_Failure, CPLE_AppDefined, "MRF: JPEG compression error");
        jpeg_destroy_compress(&cinfo);
        CPLFree(rowp);
        return CE_Failure;
    }

    // Build a bitmaps of the black pixels
    // If there are any black pixels, write a compressed mask in APP3 "C3Mask" chunk

    // Mask is initialized to all pixels valid
    BitMask mask(sz.x, sz.y);
    storage_manager mbuffer = { CHUNK_NAME, CHUNK_NAME_SIZE };

    int nzeros = (cinfo.data_precision == 8) ?
        update_mask(mask, reinterpret_cast<GByte *>(src.buffer), sz.c) :
        update_mask(mask, reinterpret_cast<GUInt16 *>(src.buffer), sz.c);

    // In case we need to build a Zen chunk
    char *buffer = nullptr; 

    if (nzeros != 0) { // build the Zen chunk
        mbuffer.size = 2 * mask.size() + CHUNK_NAME_SIZE;
        buffer = reinterpret_cast<char *>(CPLMalloc(mbuffer.size));
        if (!buffer) {
            jpeg_destroy_compress(&cinfo);
            CPLFree(rowp);
            CPLError(CE_Failure, CPLE_OutOfMemory, "MRF: JPEG Zen mask compression");
            return CE_Failure;
        }

        memcpy(buffer, CHUNK_NAME, CHUNK_NAME_SIZE);
        mbuffer.buffer = buffer + CHUNK_NAME_SIZE;
        mbuffer.size -= CHUNK_NAME_SIZE;

        RLEC3Packer c3;
        mask.set_packer(&c3);
        if (!mask.store(&mbuffer)) {
            CPLError(CE_Failure, CPLE_AppDefined, "MRF: JPEG Zen mask compression");
            CPLFree(rowp);
            CPLFree(buffer);
            return CE_Failure;
        }

        // Change the buffer pointer to include the signature, on output the size is the compressed size
        mbuffer.buffer = buffer;
        mbuffer.size += CHUNK_NAME_SIZE;

        // Check that the size fits in one JPEG chunk
        if (mbuffer.size + 2 + CHUNK_NAME_SIZE > 65535) {
            // Should split it in multiple chunks, for now mark this tile as all data and emit a warning
            CPLError(CE_Warning, CPLE_NotSupported, "MRF: JPEG Zen mask too large");
            mbuffer.size = CHUNK_NAME_SIZE; // Write just the signature
        }
    }

    // Everything is ready
    jpeg_start_compress(&cinfo, TRUE);

    // Always write the Zen app chunk, App3
    jpeg_write_marker(&cinfo, JPEG_APP0 + 3,
      reinterpret_cast<JOCTET *>(mbuffer.buffer),
      static_cast<unsigned int>(mbuffer.size));

    jpeg_write_scanlines(&cinfo, rowp, sz.y);
    jpeg_finish_compress(&cinfo);
    jpeg_destroy_compress(&cinfo);

    CPLFree(rowp);
    CPLFree(buffer);     // Safe to call on null

    // Figure out the size
    dst.size -= jmgr.free_in_buffer;

    return CE_None;
}

/************************************************************************/
/*                          ProgressMonitor()                           */
/************************************************************************/

/* Avoid the risk of denial-of-service on crafted JPEGs with an insane */
/* number of scans. */
/* See http://www.libjpeg-turbo.org/pmwiki/uploads/About/TwoIssueswiththeJPEGStandard.pdf */
static void ProgressMonitor(j_common_ptr cinfo)
{
    if (cinfo->is_decompressor)
    {
        const int scan_no =
            reinterpret_cast<j_decompress_ptr>(cinfo)->input_scan_number;
        const int MAX_SCANS = 100;
        if (scan_no >= MAX_SCANS)
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Scan number %d exceeds maximum scans (%d)",
                     scan_no, MAX_SCANS);

            MRFJPEGStruct* psJPEGStruct =
                (MRFJPEGStruct* ) cinfo->client_data;

            // return control to the setjmp point
            longjmp(psJPEGStruct->setjmpBuffer, 1);
        }
    }
}

// Returns the number of zero pixels, as well as clearing those bits int the mask
template<typename T> void apply_mask(MRFJPEGStruct &sJ, T *s, int nc) {
    if (NO_MASK == sJ.mask_state)
        return;

    BitMask *mask = sJ.mask;
    int w = mask->getWidth();
    int h = mask->getHeight();

    if (MASK_LOADED == sJ.mask_state) { // Partial map
        for (int y = 0; y < h; y++)
            for (int x = 0; x < w; x++) {
                if (mask->isSet(x, y)) { // Non zero pixel
                    for (int c = 0; c < nc; c++, s++) {
                        if (*s == 0)
                            *s = 1;
                    }
                }
                else { // Zero pixel
                    for (int c = 0; c < nc; c++)
                        *s++ = 0;
                }
            }
    }
    else if (MASK_FULL == sJ.mask_state) { // All non-zero
        for (int y = 0; y < h; y++)
            for (int x = 0; x < w; x++) {
                for (int c = 0; c < nc; c++, s++) {
                    if (*s == 0)
                        *s = 1;
                }
            }
    }
}

// JPEG marker processor, for the Zen app3 marker
// Can't return error, only works if the JPEG mask is all in the buffer
static boolean MaskProcessor(j_decompress_ptr pcinfo) {
    struct jpeg_source_mgr *src = pcinfo->src;
    if (src->bytes_in_buffer < 2)
        ERREXIT(pcinfo, JERR_CANT_SUSPEND);
    // Big endian length, two bytes
    int len = (*src->next_input_byte++) << 8;
    len += *src->next_input_byte++;
    // The length includes the two bytes we just read
    src->bytes_in_buffer -= 2;
    len -= 2;
    // Check that it is safe to read the rest
    if (src->bytes_in_buffer < static_cast<size_t>(len))
        ERREXIT(pcinfo, JERR_CANT_SUSPEND);
    MRFJPEGStruct *psJPEG = reinterpret_cast<MRFJPEGStruct *>(pcinfo->client_data);
    BitMask *mask = psJPEG->mask;
    // caller doesn't want a mask or wrong chunk, skip the chunk and return
    if (!mask || static_cast<size_t>(len) < CHUNK_NAME_SIZE
        || !EQUALN(reinterpret_cast<const char *>(src->next_input_byte), CHUNK_NAME, CHUNK_NAME_SIZE)) {
        src->bytes_in_buffer -= len;
        src->next_input_byte += len;
        return true;
    }

    // Skip the signature and load the mask
    src->bytes_in_buffer -= CHUNK_NAME_SIZE;
    src->next_input_byte += CHUNK_NAME_SIZE;
    len -= static_cast<int>(CHUNK_NAME_SIZE);
    if (len == 0) { // No mask content means mask is all full, just return
        psJPEG->mask_state = MASK_FULL;
        return true;
    }

    // It is OK to use const cast, the mask doesn't touch the buffer
    storage_manager msrc = {
        const_cast<char *>(reinterpret_cast<const char *>(src->next_input_byte)),
        static_cast<size_t>(len)
    };

    if (!mask->load(&msrc)) { // Fatal error return, mask is not valid
        ERREXIT(pcinfo, JERR_CANT_SUSPEND);
    }

    src->bytes_in_buffer -= len;
    src->next_input_byte += len;
    psJPEG->mask_state = MASK_LOADED;
    return true;
}

/**
*\brief In memory decompression of JPEG file
*
* @param data pointer to output buffer
* @param png pointer to PNG in memory
* @param sz if non-zero, test that uncompressed data fits in the buffer.
*/
#if defined(JPEG12_ON)
CPLErr JPEG_Codec::DecompressJPEG12(buf_mgr &dst, buf_mgr &isrc)
#else
CPLErr JPEG_Codec::DecompressJPEG(buf_mgr &dst, buf_mgr &isrc)
#endif

{
    int nbands = img.pagesize.c;
    // Locals, clean up after themselves
    jpeg_decompress_struct cinfo;
    MRFJPEGStruct sJPEGStruct;
    struct jpeg_error_mgr sJErr;
    BitMask mask(img.pagesize.x, img.pagesize.y);
    RLEC3Packer packer;
    mask.set_packer(&packer);

    memset(&cinfo, 0, sizeof(cinfo));
    // Pass the mask address to the decompressor
    sJPEGStruct.mask = &mask;

    struct jpeg_source_mgr src;

    cinfo.err = jpeg_std_error( &sJErr );
    sJErr.error_exit = errorExit;
    sJErr.emit_message = emitMessage;
    cinfo.client_data = (void *) &(sJPEGStruct);

    src.next_input_byte = (JOCTET *)isrc.buffer;
    src.bytes_in_buffer = isrc.size;
    src.term_source = stub_source_dec;
    src.init_source = stub_source_dec;
    src.skip_input_data = skip_input_data_dec;
    src.fill_input_buffer = fill_input_buffer_dec;
    src.resync_to_restart = jpeg_resync_to_restart;

    jpeg_create_decompress(&cinfo);

    if (setjmp(sJPEGStruct.setjmpBuffer)) {
        CPLError(CE_Failure, CPLE_AppDefined, "MRF: Error reading JPEG page");
        jpeg_destroy_decompress(&cinfo);
        return CE_Failure;
    }

    cinfo.src = &src;
    jpeg_set_marker_processor(&cinfo, JPEG_APP0 + 3, MaskProcessor);
    jpeg_read_header(&cinfo, TRUE);

    /* In some cases, libjpeg needs to allocate a lot of memory */
    /* http://www.libjpeg-turbo.org/pmwiki/uploads/About/TwoIssueswiththeJPEGStandard.pdf */
    if( jpeg_has_multiple_scans(&(cinfo)) )
    {
        /* In this case libjpeg will need to allocate memory or backing */
        /* store for all coefficients */
        /* See call to jinit_d_coef_controller() from master_selection() */
        /* in libjpeg */
        vsi_l_offset nRequiredMemory = 
            static_cast<vsi_l_offset>(cinfo.image_width) *
            cinfo.image_height * cinfo.num_components *
            ((cinfo.data_precision+7)/8);
        /* BLOCK_SMOOTHING_SUPPORTED is generally defined, so we need */
        /* to replicate the logic of jinit_d_coef_controller() */
        if( cinfo.progressive_mode )
            nRequiredMemory *= 3;

#ifndef GDAL_LIBJPEG_LARGEST_MEM_ALLOC
#define GDAL_LIBJPEG_LARGEST_MEM_ALLOC (100 * 1024 * 1024)
#endif

        if( nRequiredMemory > GDAL_LIBJPEG_LARGEST_MEM_ALLOC &&
            CPLGetConfigOption("GDAL_ALLOW_LARGE_LIBJPEG_MEM_ALLOC", nullptr) == nullptr )
        {
                CPLError(CE_Failure, CPLE_NotSupported,
                    "Reading this image would require libjpeg to allocate "
                    "at least " CPL_FRMT_GUIB " bytes. "
                    "This is disabled since above the " CPL_FRMT_GUIB " threshold. "
                    "You may override this restriction by defining the "
                    "GDAL_ALLOW_LARGE_LIBJPEG_MEM_ALLOC environment variable, "
                    "or recompile GDAL by defining the "
                    "GDAL_LIBJPEG_LARGEST_MEM_ALLOC macro to a value greater "
                    "than " CPL_FRMT_GUIB,
                    static_cast<GUIntBig>(nRequiredMemory),
                    static_cast<GUIntBig>(GDAL_LIBJPEG_LARGEST_MEM_ALLOC),
                    static_cast<GUIntBig>(GDAL_LIBJPEG_LARGEST_MEM_ALLOC));
                jpeg_destroy_decompress(&cinfo);
                return CE_Failure;
        }
    }

    // Use float, it is actually faster than the ISLOW method by a tiny bit
    cinfo.dct_method = JDCT_FLOAT;

    //
    // Tolerate different input if we can do the conversion
    // Gray and RGB for example
    // This also means that a RGB MRF can be read as grayscale and vice versa
    // If libJPEG can't convert it will throw an error
    //
    if (nbands == 3 && cinfo.num_components != nbands)
        cinfo.out_color_space = JCS_RGB;
    if (nbands == 1 && cinfo.num_components != nbands)
        cinfo.out_color_space = JCS_GRAYSCALE;

    const int datasize = ((cinfo.data_precision == 8) ? 1 : 2);
    if( cinfo.image_width > static_cast<unsigned>(INT_MAX / (nbands * datasize)) )
    {
        CPLError(CE_Failure, CPLE_AppDefined, "MRF: JPEG decompress buffer overflow");
        jpeg_destroy_decompress(&cinfo);
        return CE_Failure;
    }
    int linesize = cinfo.image_width * nbands * datasize;

    // We have a mismatch between the real and the declared data format
    // warn and fail if output buffer is too small
    if (linesize > static_cast<int>(INT_MAX / cinfo.image_height)) {
        CPLError(CE_Failure, CPLE_AppDefined, "MRF: JPEG decompress buffer overflow");
        jpeg_destroy_decompress(&cinfo);
        return CE_Failure;
    }
    if (linesize*cinfo.image_height != dst.size) {
        CPLError(CE_Warning, CPLE_AppDefined, "MRF: read JPEG size is wrong");
        if (linesize*cinfo.image_height > dst.size) {
            CPLError(CE_Failure, CPLE_AppDefined, "MRF: JPEG decompress buffer overflow");
            jpeg_destroy_decompress(&cinfo);
            return CE_Failure;
        }
    }

    struct jpeg_progress_mgr sJProgress;
    sJProgress.progress_monitor = ProgressMonitor;
    cinfo.progress = &sJProgress;

    jpeg_start_decompress(&cinfo);

    // Decompress, two lines at a time is what libjpeg does
    while (cinfo.output_scanline < cinfo.image_height) {
        char *rp[2];
        rp[0] = (char *)dst.buffer + linesize*cinfo.output_scanline;
        rp[1] = rp[0] + linesize;
        // if this fails, it calls the error handler
        // which will report an error
        if( jpeg_read_scanlines(&cinfo, JSAMPARRAY(rp), 2) == 0 )
        {
            jpeg_destroy_decompress(&cinfo);
            return CE_Failure;
        }
    }
    jpeg_finish_decompress(&cinfo);
    jpeg_destroy_decompress(&cinfo);

    // Apply the mask
    if (datasize == 1)
      apply_mask(sJPEGStruct, reinterpret_cast<char *>(dst.buffer), img.pagesize.c);
    else
      apply_mask(sJPEGStruct, reinterpret_cast<GUInt16 *>(dst.buffer), img.pagesize.c);

    return CE_None;
}

// This part gets compiled only once
#if !defined(JPEG12_ON)

// The Zen chunk signature
char CHUNK_NAME[] = "Zen";
size_t CHUNK_NAME_SIZE = strlen(CHUNK_NAME) + 1;


// Type dependent dispachers
CPLErr JPEG_Band::Decompress(buf_mgr &dst, buf_mgr &src)
{
#if defined(LIBJPEG_12_H)
    if (GDT_Byte != img.dt)
        return codec.DecompressJPEG12(dst, src);
#endif
    return codec.DecompressJPEG(dst, src);
}

CPLErr JPEG_Band::Compress(buf_mgr &dst, buf_mgr &src)
{
#if defined(LIBJPEG_12_H)
    if (GDT_Byte != img.dt)
        return codec.CompressJPEG12(dst, src);
#endif
    return codec.CompressJPEG(dst, src);
}

// PHOTOMETRIC == MULTISPECTRAL turns off YCbCr conversion and downsampling
JPEG_Band::JPEG_Band( GDALMRFDataset *pDS, const ILImage &image,
                      int b, int level ) :
    GDALMRFRasterBand(pDS, image, b, int(level)),
    codec(image)
{
    const int nbands = image.pagesize.c;
    // Check behavior on signed 16bit.  Does the libjpeg sign extend?
#if defined(LIBJPEG_12_H)
    if (GDT_Byte != image.dt && GDT_UInt16 != image.dt)
#else
    if (GDT_Byte != image.dt)
#endif
    {
        CPLError(CE_Failure, CPLE_NotSupported,
                 "Data type not supported by MRF JPEG");
        return;
    }

    if( nbands == 3 )
    { // Only the 3 band JPEG has storage flavors
        CPLString const &pm = pDS->GetPhotometricInterpretation();
        if (pm == "RGB" || pm == "MULTISPECTRAL")
        { // Explicit RGB or MS
            codec.rgb = TRUE;
            codec.sameres = TRUE;
        }
        if (pm == "YCC")
            codec.sameres = TRUE;
    }

    if( GDT_Byte == image.dt )
        codec.optimize = GetOptlist().FetchBoolean("OPTIMIZE", FALSE) != FALSE;
    else
        codec.optimize = true; // Required for 12bit
}
#endif

NAMESPACE_MRF_END