dpxlib.c

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/*
 *   Dpx image file format library routines.
 *
 *   Copyright 1999 - 2002 David Hodson <hodsond@acm.org>
 *
 *   This program is free software; you can redistribute it and/or modify it
 *   under the terms of the GNU General Public License as published by the Free
 *   Software Foundation; either version 2 of the License, or (at your option)
 *   any later version.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 *   or FITNESS FOR A PARTICULAR PURPOSE.    See the GNU General Public License
 *   for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

#include "dpxfile.h"
#include "dpxlib.h"

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <time.h>                /* strftime() */
#include <sys/types.h>
#ifdef WIN32
#include <winsock.h>
#else
#include <netinet/in.h>  /* htonl() */
#endif
#include <string.h>          /* memset */
#include "cin_debug_stuff.h"
#include "logmemfile.h"

static void
fillDpxChannelInfo(DpxFile* dpx, DpxChannelInformation* chan, int des) {

    (void)dpx; /* unused */
    
    chan->signage = 0;
    chan->ref_low_data = htonl(0);
    chan->ref_low_quantity = htonf(0.0);
    chan->ref_high_data = htonl(1023);
    chan->ref_high_quantity = htonf(2.046);
    chan->designator1 = des;
    chan->transfer_characteristics = 0;
    chan->colourimetry = 0;
    chan->bits_per_pixel = 10;
    chan->packing = htons(1);
    chan->encoding = 0;
    chan->data_offset = 0;
    chan->line_padding = htonl(0);
    chan->channel_padding = htonl(0);
    chan->description[0] = 0;
}

static void
dumpDpxChannelInfo(DpxChannelInformation* chan) {
    d_printf("  Signage %ld", (intptr_t)ntohl(chan->signage));
    d_printf("  Ref low data %ld\n", (intptr_t)ntohl(chan->ref_low_data));
    d_printf("  Ref low quantity %f\n", ntohf(chan->ref_low_quantity));
    d_printf("  Ref high data %ld\n", (intptr_t)ntohl(chan->ref_high_data));
    d_printf("  Ref high quantity %f\n", ntohf(chan->ref_high_quantity));
    d_printf("  Designator1: %d,", chan->designator1);
    d_printf("  Bits per pixel %d\n", chan->bits_per_pixel);
    d_printf("  Packing: %d,", ntohs(chan->packing));
    d_printf("  Data Offset: %ld,", (intptr_t)ntohl(chan->data_offset));
}

static void
fillDpxFileInfo(
    DpxFile* dpx, DpxFileInformation* fileInfo, const char* filename) {

    time_t fileClock;
    struct tm* fileTime;

    /* Note: always write files in network order */
    /* By the spec, it shouldn't matter, but ... */

    fileInfo->magic_num = htonl(DPX_FILE_MAGIC);
    fileInfo->offset = htonl(dpx->imageOffset);
    strcpy(fileInfo->vers, "v1.0");
    fileInfo->file_size = htonl(dpx->imageOffset +
        pixelsToLongs(dpx->height * dpx->width * dpx->depth) * 4);
    fileInfo->ditto_key = 0;
    fileInfo->gen_hdr_size = htonl(
        sizeof(DpxFileInformation) +
        sizeof(DpxImageInformation) +
        sizeof(DpxOriginationInformation));
    fileInfo->ind_hdr_size = htonl(sizeof(DpxMPIInformation));
    fileInfo->user_data_size = 0;
    strncpy(fileInfo->file_name, filename, 99);
    fileInfo->file_name[99] = 0;

    fileClock = time(0);
    fileTime = localtime(&fileClock);
    strftime(fileInfo->create_date, 24, "%Y:%m:%d:%H:%M:%S%Z", fileTime);
    /* Question: is %Z in strftime guaranteed to return 3 chars? */
    fileInfo->create_date[23] = 0;

    strcpy(fileInfo->creator, "David's DPX writer");
    fileInfo->project[0] = 0;
    fileInfo->copyright[0] = 0;
    fileInfo->key = 0xFFFFFFFF; /* same in any byte order */
}

static void
dumpDpxFileInfo(DpxFileInformation* fileInfo) {
    d_printf("\n--File Information--\n");
    d_printf("Magic: %8.8lX\n", (unsigned long)ntohl(fileInfo->magic_num));
    d_printf("Image Offset %ld\n", (intptr_t)ntohl(fileInfo->offset));
    d_printf("Version \"%s\"\n", fileInfo->vers);
    d_printf("File size %ld\n", (intptr_t)ntohl(fileInfo->file_size));
    d_printf("Ditto key %ld\n", (intptr_t)ntohl(fileInfo->ditto_key));
    d_printf("Generic Header size %ld\n", (intptr_t)ntohl(fileInfo->gen_hdr_size));
    d_printf("Industry Header size %ld\n", (intptr_t)ntohl(fileInfo->ind_hdr_size));
    d_printf("User Data size %ld\n", (intptr_t)ntohl(fileInfo->user_data_size));
    d_printf("File name \"%s\"\n", fileInfo->file_name);
    d_printf("Creation date \"%s\"\n", fileInfo->create_date);
    d_printf("Creator \"%s\"\n", fileInfo->creator);
    d_printf("Project \"%s\"\n", fileInfo->project);
    d_printf("Copyright \"%s\"\n", fileInfo->copyright);
    d_printf("Key %ld\n", (intptr_t)ntohl(fileInfo->key));
}

static void
fillDpxImageInfo(
    DpxFile* dpx, DpxImageInformation* imageInfo) {
    imageInfo->orientation = 0;
    imageInfo->channels_per_image = htons(1);
    imageInfo->pixels_per_line = htonl(dpx->width);
    imageInfo->lines_per_image = htonl(dpx->height);

    if (dpx->depth == 1) {
        fillDpxChannelInfo(dpx, &imageInfo->channel[0], 0);

    } else if (dpx->depth == 3) {
        fillDpxChannelInfo(dpx, &imageInfo->channel[0], 50);
    }
}

static void
dumpDpxImageInfo(DpxImageInformation* imageInfo) {

    int n;
    int i;
    d_printf("\n--Image Information--\n");
    d_printf("Image orientation %d,", ntohs(imageInfo->orientation));
    n = ntohs(imageInfo->channels_per_image);
    d_printf("Channels %d\n", n);
    d_printf("Pixels per line %ld\n", (intptr_t)ntohl(imageInfo->pixels_per_line));
    d_printf("Lines per image %ld\n", (intptr_t)ntohl(imageInfo->lines_per_image));
    for (i = 0; i < n; ++i) {
        d_printf("  --Channel %d--\n", i);
        dumpDpxChannelInfo(&imageInfo->channel[i]);
    }
}

static void
fillDpxOriginationInfo(
    DpxFile* dpx, DpxOriginationInformation* originInfo, DpxFileInformation* fileInfo)
{
    /* unused */
    (void)dpx;
    (void)originInfo;
    (void)fileInfo;
}

static void
dumpDpxOriginationInfo(DpxOriginationInformation* originInfo) {
    d_printf("\n--Origination Information--\n");
    d_printf("X offset %ld\n", (intptr_t)ntohl(originInfo->x_offset));
    d_printf("Y offset %ld\n", (intptr_t)ntohl(originInfo->y_offset));
    d_printf("X centre %f\n", ntohf(originInfo->x_centre));
    d_printf("Y centre %f\n", ntohf(originInfo->y_centre));
    d_printf("Original X %ld\n", (intptr_t)ntohl(originInfo->x_original_size));
    d_printf("Original Y %ld\n", (intptr_t)ntohl(originInfo->y_original_size));
    d_printf("File name \"%s\"\n", originInfo->file_name);
    d_printf("Creation time \"%s\"\n", originInfo->creation_time);
    d_printf("Input device \"%s\"\n", originInfo->input_device);
    d_printf("Serial number \"%s\"\n", originInfo->input_serial_number);
}

static void
initDpxMainHeader(DpxFile* dpx, DpxMainHeader* header, const char* shortFilename) {
    memset(header, 0, sizeof(DpxMainHeader));
    fillDpxFileInfo(dpx, &header->fileInfo, shortFilename);
    fillDpxImageInfo(dpx, &header->imageInfo);
    fillDpxOriginationInfo(dpx, &header->originInfo, &header->fileInfo);
#if 0
    fillDpxMPIInfo(dpx, &header->filmHeader);
#endif
}

static void
dumpDpxMainHeader(DpxMainHeader* header) {
    dumpDpxFileInfo(&header->fileInfo);
    dumpDpxImageInfo(&header->imageInfo);
    dumpDpxOriginationInfo(&header->originInfo);
#if 0
    dumpDpxMPIInformation(&header->filmHeader);
#endif
}

static int verbose = 0;
void
dpxSetVerbose(int verbosity) {
    verbose = verbosity;
}

static void
verboseMe(DpxFile* dpx) {

    d_printf("size %d x %d x %d\n", dpx->width, dpx->height, dpx->depth);
    d_printf("ImageStart %d, lineBufferLength %d, implied length %d\n",
        dpx->imageOffset, dpx->lineBufferLength * 4,
        dpx->imageOffset + pixelsToLongs(dpx->width * dpx->depth * dpx->height) * 4);
}

int
dpxGetRowBytes(DpxFile* dpx, unsigned short* row, int y) {

    /* Note: this code is bizarre because DPX files can wrap */
    /* packed longwords across line boundaries!!!! */

    size_t readLongs;
    unsigned int longIndex;
    int numPixels = dpx->width * dpx->depth;
    int pixelIndex;

    /* only seek if not reading consecutive lines */
    /* this is not quite right yet, need to account for leftovers */
    if (y != dpx->fileYPos) {
        int lineOffset = pixelsToLongs(y * dpx->width * dpx->depth) * 4;
        if (verbose) d_printf("Seek in getRowBytes\n");
        if (logimage_fseek(dpx, dpx->imageOffset + lineOffset, SEEK_SET) != 0) {
            if (verbose) d_printf("Couldn't seek to line %d at %d\n", y, dpx->imageOffset + lineOffset);
            return 1;
        }
        dpx->fileYPos = y;
    }

    /* read enough longwords */
    readLongs = pixelsToLongs(numPixels - dpx->pixelBufferUsed);
    if (logimage_fread(dpx->lineBuffer, 4, readLongs, dpx) != readLongs) {
        if (verbose) d_printf("Couldn't read line %d length %d\n", y, (int)readLongs * 4);
        return 1;
    }
    ++dpx->fileYPos;

    /* convert longwords to pixels */
    pixelIndex = dpx->pixelBufferUsed;

    /* this is just strange */
    if (dpx->depth == 1) {
        for (longIndex = 0; longIndex < readLongs; ++longIndex) {
            unsigned int t = ntohl(dpx->lineBuffer[longIndex]);
            dpx->pixelBuffer[pixelIndex] = t & 0x3ff;
            t = t >> 10;
            dpx->pixelBuffer[pixelIndex+1] = t & 0x3ff;
            t = t >> 10;
            dpx->pixelBuffer[pixelIndex+2] = t & 0x3ff;
            pixelIndex += 3;
        }
    } else /* if (dpx->depth == 3) */ {
        for (longIndex = 0; longIndex < readLongs; ++longIndex) {
            unsigned int t = ntohl(dpx->lineBuffer[longIndex]);
            t = t >> 2;
            dpx->pixelBuffer[pixelIndex+2] = t & 0x3ff;
            t = t >> 10;
            dpx->pixelBuffer[pixelIndex+1] = t & 0x3ff;
            t = t >> 10;
            dpx->pixelBuffer[pixelIndex] = t & 0x3ff;
            pixelIndex += 3;
        }
    }
    dpx->pixelBufferUsed = pixelIndex;

    /* extract required pixels */
    for (pixelIndex = 0; pixelIndex < numPixels; ++pixelIndex) {
        if(dpx->params.doLogarithm)
            row[pixelIndex] = dpx->lut10_16[dpx->pixelBuffer[pixelIndex]];
        else
            row[pixelIndex] = dpx->pixelBuffer[pixelIndex] << 6;
    }

    /* save remaining pixels */
    while (pixelIndex < dpx->pixelBufferUsed) {
        dpx->pixelBuffer[pixelIndex - numPixels] = dpx->pixelBuffer[pixelIndex];
        ++pixelIndex;
    }
    dpx->pixelBufferUsed -= numPixels;

    /* done! */
    return 0;
}

int
dpxSetRowBytes(DpxFile* dpx, const unsigned short* row, int y) {

    /* Note: this code is bizarre because DPX files can wrap */
    /* packed longwords across line boundaries!!!! */

    size_t writeLongs;
    int longIndex;
    int numPixels = dpx->width * dpx->depth;
    int pixelIndex;
    int pixelIndex2;

    /* only seek if not reading consecutive lines */
    /* this is not quite right yet */
    if (y != dpx->fileYPos) {
        int lineOffset = pixelsToLongs(y * dpx->width * dpx->depth) * 4;
        if (verbose) d_printf("Seek in getRowBytes\n");
        if (logimage_fseek(dpx, dpx->imageOffset + lineOffset, SEEK_SET) != 0) {
            if (verbose) d_printf("Couldn't seek to line %d at %d\n", y, dpx->imageOffset + lineOffset);
            return 1;
        }
        dpx->fileYPos = y;
    }

    /* put new pixels into pixelBuffer */
    for (pixelIndex = 0; pixelIndex < numPixels; ++pixelIndex) {
        if(dpx->params.doLogarithm)
            dpx->pixelBuffer[dpx->pixelBufferUsed + pixelIndex] = dpx->lut16_16[row[pixelIndex]];
        else
            dpx->pixelBuffer[dpx->pixelBufferUsed + pixelIndex] = row[pixelIndex] >> 6;
    }
    dpx->pixelBufferUsed += numPixels;

    /* pack into longwords */
    writeLongs = dpx->pixelBufferUsed / 3;
    /* process whole line at image end */
    if (dpx->fileYPos == (dpx->height - 1)) {
        writeLongs = pixelsToLongs(dpx->pixelBufferUsed);
    }
    pixelIndex = 0;
    if (dpx->depth == 1) {
        for (longIndex = 0; longIndex < writeLongs; ++longIndex) {
            unsigned int t = dpx->pixelBuffer[pixelIndex] |
                    (dpx->pixelBuffer[pixelIndex+1] << 10) |
                    (dpx->pixelBuffer[pixelIndex+2] << 20);
            dpx->lineBuffer[longIndex] = htonl(t);
            pixelIndex += 3;
        }
    } else {
        for (longIndex = 0; longIndex < writeLongs; ++longIndex) {
            unsigned int t = dpx->pixelBuffer[pixelIndex+2] << 2 |
                    (dpx->pixelBuffer[pixelIndex+1] << 12) |
                    (dpx->pixelBuffer[pixelIndex] << 22);
            dpx->lineBuffer[longIndex] = htonl(t);
            pixelIndex += 3;
        }
    }

    /* write them */
    if (fwrite(dpx->lineBuffer, 4, writeLongs, dpx->file) != writeLongs) {
        if (verbose) d_printf("Couldn't write line %d length %d\n", y, (int)writeLongs * 4);
        return 1;
    }
    ++dpx->fileYPos;

    /* save remaining pixels */
    pixelIndex2 = 0;
    while (pixelIndex < dpx->pixelBufferUsed) {
        dpx->pixelBuffer[pixelIndex2] = dpx->pixelBuffer[pixelIndex];
        ++pixelIndex;
        ++pixelIndex2;
    }
    dpx->pixelBufferUsed = pixelIndex2;

    return 0;
}

#define LFMEMFILE   0
#define LFREALFILE  1

static DpxFile* 
intern_dpxOpen(int mode, const char* bytestuff, int bufsize) {

    DpxMainHeader header;
    const char *filename = bytestuff;
    DpxFile* dpx = (DpxFile*)malloc(sizeof(DpxFile));
    
    if (dpx == 0) {
        if (verbose) d_printf("Failed to malloc dpx file structure.\n");
        return 0;
    }

    /* for close routine */
    dpx->file = 0;
    dpx->lineBuffer = 0;
    dpx->pixelBuffer = 0;

    if (mode == LFREALFILE) {
        filename = bytestuff;
        dpx->file = fopen(filename, "rb");
        if (dpx->file == 0) {   
            if (verbose) d_printf("Failed to open file \"%s\".\n", filename);
            dpxClose(dpx);
            return 0;
        }
        dpx->membuffer = 0;
        dpx->memcursor = 0;
        dpx->membuffersize = 0;
    } else if (mode == LFMEMFILE) {
        dpx->membuffer = (unsigned char *)bytestuff;
        dpx->memcursor = (unsigned char *)bytestuff;
        dpx->membuffersize = bufsize;
    }
    
    dpx->reading = 1;

    if (logimage_fread(&header, sizeof(header), 1, dpx) == 0) {
        if (verbose) d_printf("Not enough data for header in \"%s\".\n", filename);
        dpxClose(dpx);
        return 0;
    }

    /* let's assume dpx files are always network order */
    if (header.fileInfo.magic_num != ntohl(DPX_FILE_MAGIC)) {
        if (verbose) d_printf("Bad magic number %8.8lX in \"%s\".\n",
            (uintptr_t)ntohl(header.fileInfo.magic_num), filename);
        dpxClose(dpx);
        return 0;
    }

    if (ntohs(header.imageInfo.channel[0].packing) != 1) {
        if (verbose) d_printf("Unknown packing %d\n", header.imageInfo.channel[0].packing);
        dpxClose(dpx);
        return 0;
    }


    dpx->width = ntohl(header.imageInfo.pixels_per_line);
    dpx->height = ntohl(header.imageInfo.lines_per_image);
    dpx->depth = ntohs(header.imageInfo.channels_per_image);
    /* Another DPX vs Cineon wierdness */
    if (dpx->depth == 1) {
        switch (header.imageInfo.channel[0].designator1) {
        case 50: dpx->depth = 3; break;
        case 51: dpx->depth = 4; break;
        case 52: dpx->depth = 4; break;
        default: break;
        }
    }
    /* dpx->bitsPerPixel = 10; */
    dpx->bitsPerPixel = header.imageInfo.channel[0].bits_per_pixel;
    if (dpx->bitsPerPixel != 10) {
        if (verbose) d_printf("Don't support depth: %d\n", dpx->bitsPerPixel);
        dpxClose(dpx);
        return 0;
    }

    dpx->imageOffset = ntohl(header.fileInfo.offset);
    dpx->lineBufferLength = pixelsToLongs(dpx->width * dpx->depth);
    dpx->lineBuffer = malloc(dpx->lineBufferLength * 4);
    if (dpx->lineBuffer == 0) {
        if (verbose) d_printf("Couldn't malloc line buffer of size %d\n", dpx->lineBufferLength * 4);
        dpxClose(dpx);
        return 0;
    }

    /* could have 2 pixels left over */
    dpx->pixelBuffer = malloc((dpx->lineBufferLength * 3 + 2) * sizeof(unsigned short));
    if (dpx->pixelBuffer == 0) {
        if (verbose) d_printf("Couldn't malloc pixel buffer of size %d\n",
                (dpx->width * dpx->depth + 2 + 2) * (int)sizeof(unsigned short));
        dpxClose(dpx);
        return 0;
    }
    dpx->pixelBufferUsed = 0;

    if (logimage_fseek(dpx, dpx->imageOffset, SEEK_SET) != 0) {
        if (verbose) d_printf("Couldn't seek to image data start at %d\n", dpx->imageOffset);
        dpxClose(dpx);
        return 0;
    }
    dpx->fileYPos = 0;

    logImageGetByteConversionDefaults(&dpx->params);
    /* The SMPTE define this code:
     *  0 - User-defined
     *  1 - Printing density
     *  2 - Linear
     *  3 - Logarithmic
     *  4 - Unspecified video
     *  5 - SMPTE 240M
     *  6 - CCIR 709-1
     *  7 - CCIR 601-2 system B or G
     *  8 - CCIR 601-2 system M
     *  9 - NTSC composite video
     *  10 - PAL composite video
     *  11 - Z linear
     *  12 - homogeneous
     *
     * Note that transfer_characteristics is U8, don't need
     * check the byte order.
     */
    
    switch (header.imageInfo.channel[0].transfer_characteristics) {
        case 1:
        case 2: /* linear */
            dpx->params.doLogarithm= 0;
            break;
        
        case 3:
            dpx->params.doLogarithm= 1;
            break;
        
        /* TODO - Unsupported, but for now just load them,
         * colors may look wrong, but can solve color conversion later
         */
        case 4: 
        case 5:
        case 6:
        case 7:
        case 8:
        case 9:
        case 10:
        case 11:
        case 12:
            if (verbose) d_printf("Un-supported Transfer Characteristics: %d using linear color conversion\n", header.imageInfo.channel[0].transfer_characteristics);
            dpx->params.doLogarithm= 0;
            break;
        default:
            if (verbose) d_printf("Un-supported Transfer Characteristics: %d\n", header.imageInfo.channel[0].transfer_characteristics);
            dpxClose(dpx);
            return 0;
            break;
    }
    setupLut(dpx);

    dpx->getRow = &dpxGetRowBytes;
    dpx->setRow = 0;
    dpx->close = &dpxClose;

    if (verbose) {
        verboseMe(dpx);
    }

    return dpx;
}

DpxFile* 
dpxOpen(const char *filename) {
    return intern_dpxOpen(LFREALFILE, filename, 0);
}

DpxFile* 
dpxOpenFromMem(unsigned char *buffer, unsigned int size) {
    return intern_dpxOpen(LFMEMFILE, (const char *) buffer, size);
}

int 
dpxIsMemFileCineon(void *buffer) {
    int magicnum = 0;
    magicnum = *((int*)buffer);
    if (magicnum == ntohl(DPX_FILE_MAGIC)) return 1;
    else return 0;
}

DpxFile*
dpxCreate(const char* filename, int width, int height, int depth) {

    /* Note: always write files in network order */
    /* By the spec, it shouldn't matter, but ... */

    DpxMainHeader header;
    const char* shortFilename = 0;

    DpxFile* dpx = (DpxFile*)malloc(sizeof(DpxFile));
    if (dpx == 0) {
        if (verbose) d_printf("Failed to malloc dpx file structure.\n");
        return 0;
    }

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

    /* for close routine */
    dpx->file = 0;
    dpx->lineBuffer = 0;
    dpx->pixelBuffer = 0;

    dpx->file = fopen(filename, "wb");
    if (dpx->file == 0) {
        if (verbose) d_printf("Couldn't open file %s\n", filename);
        dpxClose(dpx);
        return 0;
    }
    dpx->reading = 0;

    dpx->width = width;
    dpx->height = height;
    dpx->depth = depth;
    dpx->bitsPerPixel = 10;
    dpx->imageOffset = sizeof(DpxMainHeader);

    dpx->lineBufferLength = pixelsToLongs(dpx->width * dpx->depth);
    dpx->lineBuffer = malloc(dpx->lineBufferLength * 4);
    if (dpx->lineBuffer == 0) {
        if (verbose) d_printf("Couldn't malloc line buffer of size %d\n", dpx->lineBufferLength * 4);
        dpxClose(dpx);
        return 0;
    }

    dpx->pixelBuffer = malloc((dpx->lineBufferLength * 3 + 2) * sizeof(unsigned short));
    if (dpx->pixelBuffer == 0) {
        if (verbose) d_printf("Couldn't malloc pixel buffer of size %d\n",
                (dpx->width * dpx->depth + 2 + 2) * (int)sizeof(unsigned short));
        dpxClose(dpx);
        return 0;
    }
    dpx->pixelBufferUsed = 0;

    /* find trailing part of filename */
    shortFilename = strrchr(filename, '/');
    if (shortFilename == 0) {
        shortFilename = filename;
    } else {
        ++shortFilename;
    }
    initDpxMainHeader(dpx, &header, shortFilename);
    logImageGetByteConversionDefaults(&dpx->params);
    /* Need set the file type before write the header!
     *  2 - Linear
     *  3 - Logarithmic
     *
     * Note that transfer characteristics is U8, don't need
     * check the byte order.
     */
    if (dpx->params.doLogarithm == 0)
        header.imageInfo.channel[0].transfer_characteristics= 2;
    else
        header.imageInfo.channel[0].transfer_characteristics= 3;

    if (fwrite(&header, sizeof(header), 1, dpx->file) == 0) {
        if (verbose) d_printf("Couldn't write image header\n");
        dpxClose(dpx);
        return 0;
    }
    dpx->fileYPos = 0;
    setupLut(dpx);

    dpx->getRow = 0;
    dpx->setRow = &dpxSetRowBytes;
    dpx->close = &dpxClose;

    return dpx;
}

void
dpxClose(DpxFile* dpx) {

    if (dpx == 0) {
        return;
    }

    if (dpx->file) {
        fclose(dpx->file);
        dpx->file = 0;
    }

    if (dpx->lineBuffer) {
        free(dpx->lineBuffer);
        dpx->lineBuffer = 0;
    }

    if (dpx->pixelBuffer) {
        free(dpx->pixelBuffer);
        dpx->pixelBuffer = 0;
    }

    free(dpx);
}

void
dpxDump(const char* filename) {

    DpxMainHeader header;
    FILE* file;

    file = fopen(filename, "rb");
    if (file == 0) {
        d_printf("Failed to open file \"%s\".\n", filename);
        return;
    }

    if (fread(&header, sizeof(header), 1, file) == 0) {
        d_printf("Not enough data for header in \"%s\".\n", filename);
        fclose(file);
        return;
    }

    fclose(file);
    dumpDpxMainHeader(&header);
}