/*====================================================================*

 -  Copyright (C) 2001 Leptonica.  All rights reserved.

 -

 -  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.

 -

 -  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 ANY

 -  CONTRIBUTORS 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.

 *====================================================================*/

/*!

 * \file bmpio.c

 * <pre>

 *

 *      Read bmp

 *           PIX          *pixReadStreamBmp()

 *           PIX          *pixReadMemBmp()

 *

 *      Write bmp

 *           l_int32       pixWriteStreamBmp()

 *           l_int32       pixWriteMemBmp()

 *

 * </pre>

 */

#ifdef HAVE_CONFIG_H

#include <config_auto.h>

#endif  /* HAVE_CONFIG_H */

#include <string.h>

#include "allheaders.h"

#include "pix_internal.h"

#include "bmp.h"

/* --------------------------------------------*/

#if  USE_BMPIO   /* defined in environ.h */

/* --------------------------------------------*/

    /* Here we're setting the pixel value 0 to white (255) and the

     * value 1 to black (0).  This is the convention for grayscale, but

     * the opposite of the convention for 1 bpp, where 0 is white

     * and 1 is black.  Both colormap entries are opaque (alpha = 255) */

RGBA_QUAD   bwmap[2] = { {255,255,255,255}, {0,0,0,255} };

    /* Image dimension limits */

static const l_int32  L_MAX_ALLOWED_WIDTH = 1000000;

static const l_int32  L_MAX_ALLOWED_HEIGHT = 1000000;

static const l_int64  L_MAX_ALLOWED_PIXELS = 400000000LL;

static const l_int32  L_MAX_ALLOWED_RES = 10000000;  /* pixels/meter */

#ifndef  NO_CONSOLE_IO

#define  DEBUG     0

#endif  /* ~NO_CONSOLE_IO */

/*--------------------------------------------------------------*

 *                              Read bmp                        *

 *--------------------------------------------------------------*/

/*!

 * \brief   pixReadStreamBmp()

 *

 * \param[in]    fp file stream opened for read

 * \return  pix, or NULL on error

 *

 * <pre>

 * Notes:

 *      (1) Here are references on the bmp file format:

 *          http://en.wikipedia.org/wiki/BMP_file_format

 *          http://www.fortunecity.com/skyscraper/windows/364/bmpffrmt.html

 * </pre>

 */

PIX *

pixReadStreamBmp(FILE  *fp)

{

l_uint8  *data;

size_t    size;

PIX      *pix;

    if (!fp)

        return (PIX *)ERROR_PTR("fp not defined", __func__, NULL);

        /* Read data from file and decode into Y,U,V arrays */

    rewind(fp);

    if ((data = l_binaryReadStream(fp, &size)) == NULL)

        return (PIX *)ERROR_PTR("data not read", __func__, NULL);

    pix = pixReadMemBmp(data, size);

    LEPT_FREE(data);

    return pix;

}

/*!

 * \brief   pixReadMemBmp()

 *

 * \param[in]    cdata    bmp data

 * \param[in]    size     number of bytes of bmp-formatted data

 * \return  pix, or NULL on error

 *

 * <pre>

 * Notes:

 *      (1) The BMP file is organized as follows:

 *          * 14 byte fileheader

 *          * Variable size infoheader: 40, 108 or 124 bytes.

 *            We only use data in he first 40 bytes.

 *          * Optional colormap, with size 4 * ncolors (in bytes)

 *          * Image data

 *      (2) 2 bpp bmp files are not valid in the original spec, but they

 *          are valid in later versions.

 *      (3) We support reading rgb files with bpp = 24 and rgba files

 *          with 32 bpp.  For the latter, the transparency component of

 *          the generated pix is saved; however, for rgba images with

 *          non-opaque transparent components, png provides more flexibility.

 * </pre>

 */

PIX *

pixReadMemBmp(const l_uint8  *cdata,

              size_t          size)

{

l_uint8    pel[4];

l_uint8   *cmapBuf, *fdata, *data;

l_int16    bftype, depth, d;

l_int32    offset, ihbytes, width, height, height_neg, xres, yres, spp;

l_int32    compression, imagebytes, fdatabytes, cmapbytes, ncolors, maxcolors;

l_int32    fdatabpl, extrabytes, filebpp, pixWpl, pixBpl, i, j, k;

l_uint32  *line, *pixdata, *pword;

l_int64    npixels;

BMP_FH    *bmpfh;

#if defined(__GNUC__)

BMP_HEADER *bmph;

#define bmpih (&bmph->bmpih)

#else

BMP_IH    *bmpih;

#endif

PIX       *pix, *pix1;

PIXCMAP   *cmap;

    if (!cdata)

        return (PIX *)ERROR_PTR("cdata not defined", __func__, NULL);

    if (size < sizeof(BMP_FH) + sizeof(BMP_IH))

        return (PIX *)ERROR_PTR("bmf size error", __func__, NULL);

        /* Verify this is an uncompressed bmp */

    bmpfh = (BMP_FH *)cdata;

    bftype = bmpfh->bfType[0] + ((l_int32)bmpfh->bfType[1] << 8);

    if (bftype != BMP_ID)

        return (PIX *)ERROR_PTR("not bmf format", __func__, NULL);

#if defined(__GNUC__)

    bmph = (BMP_HEADER *)bmpfh;

#else

    bmpih = (BMP_IH *)(cdata + BMP_FHBYTES);

#endif

    compression = convertOnBigEnd32(bmpih->biCompression);

    if (compression != 0)

        return (PIX *)ERROR_PTR("cannot read compressed BMP files",

                                __func__, NULL);

        /* Find the offset from the beginning of the file to the image data */

    offset = bmpfh->bfOffBits[0];

    offset += (l_int32)bmpfh->bfOffBits[1] << 8;

    offset += (l_int32)bmpfh->bfOffBits[2] << 16;

    offset += (l_uint32)bmpfh->bfOffBits[3] << 24;

        /* Read the remaining useful data in the infoheader.

         * Note that the first 4 bytes give the infoheader size. */

    ihbytes = convertOnBigEnd32(*(l_uint32 *)(bmpih));

    width = convertOnBigEnd32(bmpih->biWidth);

    height = convertOnBigEnd32(bmpih->biHeight);

    depth = convertOnBigEnd16(bmpih->biBitCount);

    imagebytes = convertOnBigEnd32(bmpih->biSizeImage);

    xres = convertOnBigEnd32(bmpih->biXPelsPerMeter);

    yres = convertOnBigEnd32(bmpih->biYPelsPerMeter);

        /* Some sanity checking.  We impose limits on the image

         * dimensions, resolution and number of pixels.  We make sure the

         * file is the correct size to hold the amount of uncompressed data

         * that is specified in the header.  The number of colormap

         * entries is checked: it can be either 0 (no cmap) or some

         * number between 2 and 256.

         * Note that the imagebytes for uncompressed images is either

         * 0 or the size of the file data.  (The fact that it can

         * be 0 is perhaps some legacy glitch). */

    if (width < 1)

        return (PIX *)ERROR_PTR("width < 1", __func__, NULL);

    if (width > L_MAX_ALLOWED_WIDTH)

        return (PIX *)ERROR_PTR("width too large", __func__, NULL);

    if (height == 0 || height < -L_MAX_ALLOWED_HEIGHT ||

        height > L_MAX_ALLOWED_HEIGHT)

        return (PIX *)ERROR_PTR("invalid height", __func__, NULL);

    if (xres < 0 || xres > L_MAX_ALLOWED_RES ||

        yres < 0 || yres > L_MAX_ALLOWED_RES)

        return (PIX *)ERROR_PTR("invalid resolution", __func__, NULL);

    height_neg = 0;

    if (height < 0) {

        height_neg = 1;

        height = -height;

    }

    if (ihbytes != 40 && ihbytes != 108 && ihbytes != 124) {

        L_ERROR("invalid ihbytes = %d; not in {40, 108, 124}\n",

                __func__, ihbytes);

        return NULL;

    }

    npixels = 1LL * width * height;

    if (npixels > L_MAX_ALLOWED_PIXELS)

        return (PIX *)ERROR_PTR("npixels too large", __func__, NULL);

    if (depth != 1 && depth != 2 && depth != 4 && depth != 8 &&

        depth != 16 && depth != 24 && depth != 32) {

        L_ERROR("invalid depth = %d; not in {1, 2, 4, 8, 16, 24, 32}\n",

                __func__, depth);

        return NULL;

    }

    fdatabpl = 4 * ((1LL * width * depth + 31)/32);

    fdatabytes = fdatabpl * height;

    if (imagebytes != 0 && imagebytes != fdatabytes) {

        L_ERROR("invalid imagebytes = %d; not equal to fdatabytes = %d\n",

                __func__, imagebytes, fdatabytes);

        return NULL;

    }

        /* In the original spec, BITMAPINFOHEADER is 40 bytes.

         * There have been a number of revisions, to capture more information.

         * For example, the fifth version, BITMAPV5HEADER, adds 84 bytes

         * of ICC color profiles.  We use the size of the infoheader

         * to accommodate these newer formats.  Knowing the size of the

         * infoheader gives more opportunity to sanity check input params. */

    cmapbytes = offset - BMP_FHBYTES - ihbytes;

    ncolors = cmapbytes / sizeof(RGBA_QUAD);

    if (ncolors < 0 || ncolors == 1)

        return (PIX *)ERROR_PTR("invalid: cmap size < 0 or 1", __func__, NULL);

    if (ncolors > 0 && depth > 8)

        return (PIX *)ERROR_PTR("can't have cmap for d > 8", __func__, NULL);

    maxcolors = (depth <= 8) ? 1 << depth : 0;

    if (ncolors > maxcolors) {

        L_ERROR("cmap too large for depth %d: ncolors = %d > maxcolors = %d\n",

                __func__, depth, ncolors, maxcolors);

        return NULL;

    }

    if (size != 1LL * offset + 1LL * fdatabytes)

        return (PIX *)ERROR_PTR("size incommensurate with image data",

                                __func__,NULL);

        /* Handle the colormap */

    cmapBuf = NULL;

    if (ncolors > 0) {

        if ((cmapBuf = (l_uint8 *)LEPT_CALLOC(ncolors, sizeof(RGBA_QUAD)))

                 == NULL)

            return (PIX *)ERROR_PTR("cmapBuf alloc fail", __func__, NULL );

            /* Read the colormap entry data from bmp. The RGBA_QUAD colormap

             * entries are used for both bmp and leptonica colormaps. */

        memcpy(cmapBuf, cdata + BMP_FHBYTES + ihbytes,

               ncolors * sizeof(RGBA_QUAD));

    }

        /* Make a 32 bpp pix if file depth is 24 bpp */

    d = (depth == 24) ? 32 : depth;

    if ((pix = pixCreate(width, height, d)) == NULL) {

        LEPT_FREE(cmapBuf);

        return (PIX *)ERROR_PTR( "pix not made", __func__, NULL);

    }

    pixSetXRes(pix, (l_int32)((l_float32)xres / 39.37 + 0.5));  /* to ppi */

    pixSetYRes(pix, (l_int32)((l_float32)yres / 39.37 + 0.5));  /* to ppi */

    pixSetInputFormat(pix, IFF_BMP);

    pixWpl = pixGetWpl(pix);

    pixBpl = 4 * pixWpl;

    if (depth <= 16)

        spp = 1;

    else if (depth == 24)

        spp = 3;

    else  /* depth == 32 */

        spp = 4;

    pixSetSpp(pix, spp);

        /* Convert the bmp colormap to a pixcmap */

    cmap = NULL;

    if (ncolors > 0) {  /* import the colormap to the pix cmap */

        cmap = pixcmapCreate(L_MIN(d, 8));

        LEPT_FREE(cmap->array);  /* remove generated cmap array */

        cmap->array  = (void *)cmapBuf;  /* and replace */

        cmap->n = L_MIN(ncolors, 256);

        for (i = 0; i < cmap->n; i++)   /* set all colors opaque */

            pixcmapSetAlpha (cmap, i, 255);

    }

    if (pixSetColormap(pix, cmap)) {

        pixDestroy(&pix);

        return (PIX *)ERROR_PTR("invalid colormap", __func__, NULL);

    }

        /* Acquire the image data.  Image origin for bmp is at lower right. */

    fdata = (l_uint8 *)cdata + offset;  /* start of the bmp image data */

    pixdata = pixGetData(pix);

    if (depth != 24 && depth != 32) {  /* typ. 1 or 8 bpp */

        data = (l_uint8 *)pixdata + pixBpl * (height - 1);

        for (i = 0; i < height; i++) {

            memcpy(data, fdata, fdatabpl);

            fdata += fdatabpl;

            data -= pixBpl;

        }

    } else {  /*  24 or 32 bpp file; 32 bpp pix

             *  Note: for rgb bmp files, pel[0] is blue, pel[1] is green,

             *  and pel[2] is red.  This is opposite to the storage

             *  in the pix, which puts the red pixel in the 0 byte,

             *  the green in the 1 byte and the blue in the 2 byte.

             *  Note also that all words are endian flipped after

             *  assignment on L_LITTLE_ENDIAN platforms.

             *

             *  We can then make these assignments for little endians:

             *      SET_DATA_BYTE(pword, 1, pel[0]);      blue

             *      SET_DATA_BYTE(pword, 2, pel[1]);      green

             *      SET_DATA_BYTE(pword, 3, pel[2]);      red

             *  This looks like:

             *          3  (R)     2  (G)        1  (B)        0

             *      |-----------|------------|-----------|-----------|

             *  and after byte flipping:

             *           3          2  (B)     1  (G)        0  (R)

             *      |-----------|------------|-----------|-----------|

             *

             *  For big endians we set:

             *      SET_DATA_BYTE(pword, 2, pel[0]);      blue

             *      SET_DATA_BYTE(pword, 1, pel[1]);      green

             *      SET_DATA_BYTE(pword, 0, pel[2]);      red

             *  This looks like:

             *          0  (R)     1  (G)        2  (B)        3

             *      |-----------|------------|-----------|-----------|

             *  so in both cases we get the correct assignment in the PIX.

             *

             *  Can we do a platform-independent assignment?

             *  Yes, set the bytes without using macros:

             *      *((l_uint8 *)pword) = pel[2];           red

             *      *((l_uint8 *)pword + 1) = pel[1];       green

             *      *((l_uint8 *)pword + 2) = pel[0];       blue

             *  For little endians, before flipping, this looks again like:

             *          3  (R)     2  (G)        1  (B)        0

             *      |-----------|------------|-----------|-----------|

             *

             *  For reading an spp == 4 file with a transparency component,

             *  the code below shows where the alpha component is located

             *  in each pixel.

             */

        filebpp = (depth == 24) ? 3 : 4;

        extrabytes = fdatabpl - filebpp * width;

        line = pixdata + pixWpl * (height - 1);

        for (i = 0; i < height; i++) {

            for (j = 0; j < width; j++) {

                pword = line + j;

                memcpy(&pel, fdata, filebpp);

                fdata += filebpp;

                *((l_uint8 *)pword + COLOR_RED) = pel[2];

                *((l_uint8 *)pword + COLOR_GREEN) = pel[1];

                *((l_uint8 *)pword + COLOR_BLUE) = pel[0];

                    /* Set the alpha byte to opaque for rgb */

                if (depth == 24)

                    *((l_uint8 *)pword + L_ALPHA_CHANNEL) = 255;

                else

                    *((l_uint8 *)pword + L_ALPHA_CHANNEL) = pel[3];

            }

            if (extrabytes) {

                for (k = 0; k < extrabytes; k++) {

                    memcpy(&pel, fdata, 1);

                    fdata++;

                }

            }

            line -= pixWpl;

        }

    }

    pixEndianByteSwap(pix);

    if (height_neg)

        pixFlipTB(pix, pix);

        /* ----------------------------------------------

         * We do not use 1 bpp pix with colormaps in leptonica.

         * The colormap must be removed in such a way that the pixel

         * values are not changed.  If the values are only black and

         * white, return a 1 bpp image; if gray, return an 8 bpp pix;

         * otherwise, return a 32 bpp rgb pix.

         * ---------------------------------------------- */

    if (depth == 1 && cmap) {

        L_INFO("removing opaque cmap from 1 bpp\n", __func__);

        pix1 = pixRemoveColormap(pix, REMOVE_CMAP_BASED_ON_SRC);

        pixDestroy(&pix);

        pix = pix1;  /* rename */

    }

    return pix;

}

/*--------------------------------------------------------------*

 *                            Write bmp                         *

 *--------------------------------------------------------------*/

/*!

 * \brief   pixWriteStreamBmp()

 *

 * \param[in]    fp     file stream

 * \param[in]    pix    all depths

 * \return  0 if OK, 1 on error

 */

l_ok

pixWriteStreamBmp(FILE  *fp,

                  PIX   *pix)

{

l_uint8  *data;

size_t    size, nbytes;

    if (!fp)

        return ERROR_INT("stream not defined", __func__, 1);

    if (!pix)

        return ERROR_INT("pix not defined", __func__, 1);

    pixWriteMemBmp(&data, &size, pix);

    rewind(fp);

    nbytes = fwrite(data, 1, size, fp);

    free(data);

    if (nbytes != size)

        return ERROR_INT("Write error", __func__, 1);

    return 0;

}

/*!

 * \brief   pixWriteMemBmp()

 *

 * \param[out]   pfdata   data of bmp formatted image

 * \param[out]   pfsize    size of returned data

 * \param[in]    pixs      1, 2, 4, 8, 16, 32 bpp

 * \return  0 if OK, 1 on error

 *

 * <pre>

 * Notes:

 *      (1) 2 bpp bmp files are not valid in the original spec, and are

 *          written as 8 bpp.

 *      (2) pix with depth <= 8 bpp are written with a colormap.

 *          16 bpp gray and 32 bpp rgb pix are written without a colormap.

 *      (3) The transparency component in an rgba (spp = 4) pix is written.

 *      (4) The bmp colormap entries, RGBA_QUAD, are the same as

 *          the ones used for colormaps in leptonica.  This allows

 *          a simple memcpy for bmp output.

 * </pre>

 */

l_ok

pixWriteMemBmp(l_uint8  **pfdata,

               size_t    *pfsize,

               PIX       *pixs)

{

l_uint8     pel[4];

l_uint8    *cta = NULL;     /* address of the bmp color table array */

l_uint8    *fdata, *data, *fmdata;

l_int32     cmaplen;      /* number of bytes in the bmp colormap */

l_int32     ncolors, val, stepsize, w, h, d, fdepth, xres, yres, valid;

l_int32     pixWpl, pixBpl, extrabytes, spp, fBpl, fWpl, i, j, k;

l_int32     heapcm;  /* extra copy of cta on the heap ? 1 : 0 */

l_uint32    offbytes, fimagebytes;

l_uint32   *line, *pword;

size_t      fsize;

BMP_FH     *bmpfh;

#if defined(__GNUC__)

BMP_HEADER *bmph;

#define bmpih (&bmph->bmpih)

#else

BMP_IH     *bmpih;

#endif

PIX        *pix;

PIXCMAP    *cmap;

RGBA_QUAD  *pquad;

    if (pfdata) *pfdata = NULL;

    if (pfsize) *pfsize = 0;

    if (!pfdata)

        return ERROR_INT("&fdata not defined", __func__, 1 );

    if (!pfsize)

        return ERROR_INT("&fsize not defined", __func__, 1 );

    if (!pixs)

        return ERROR_INT("pixs not defined", __func__, 1);

        /* Verify validity of colormap */

    if ((cmap = pixGetColormap(pixs)) != NULL) {

        pixcmapIsValid(cmap, pixs, &valid);

        if (!valid)

            return ERROR_INT("colormap is not valid", __func__, 1);

    }

    pixGetDimensions(pixs, &w, &h, &d);

    spp = pixGetSpp(pixs);

    if (spp != 1 && spp != 3 && spp != 4) {

        L_ERROR("unsupported spp = %d\n", __func__, spp);

        return 1;

    } 

    if (d == 2) {

        L_WARNING("2 bpp files can't be read; converting to 8 bpp\n",

                  __func__);

        pix = pixConvert2To8(pixs, 0, 85, 170, 255, 1);

        d = 8;

    } else if (d == 24) {

        pix = pixConvert24To32(pixs);

        d = 32;

    } else {

        pix = pixCopy(NULL, pixs);

    }

        /* Find the bits/pixel to be written to file */

    if (spp == 1)

        fdepth = d;

    else if (spp == 3)

        fdepth = 24;

    else  /* spp == 4 */

        fdepth = 32;

        /* Resolution is given in pixels/meter */

    xres = (l_int32)(39.37 * (l_float32)pixGetXRes(pix) + 0.5);

    yres = (l_int32)(39.37 * (l_float32)pixGetYRes(pix) + 0.5);

    pixWpl = pixGetWpl(pix);

    pixBpl = 4 * pixWpl;

    fWpl = (w * fdepth + 31) / 32;

    fBpl = 4 * fWpl;

    fimagebytes = h * fBpl;

    if (fimagebytes > 4LL * L_MAX_ALLOWED_PIXELS) {

        pixDestroy(&pix);

        return ERROR_INT("image data is too large", __func__, 1);

    }

        /* If not rgb or 16 bpp, the bmp data is required to have a colormap */

    heapcm = 0;

    if (d == 32 || d == 16) {   /* 24 bpp rgb or 16 bpp: no colormap */

        ncolors = 0;

        cmaplen = 0;

    } else if ((cmap = pixGetColormap(pix))) {   /* existing colormap */

        ncolors = pixcmapGetCount(cmap);

        cmaplen = ncolors * sizeof(RGBA_QUAD);

        cta = (l_uint8 *)cmap->array;

    } else {   /* no existing colormap; d <= 8; make a binary or gray one */

        if (d == 1) {

            cmaplen  = sizeof(bwmap);

            ncolors = 2;

            cta = (l_uint8 *)bwmap;

        } else {   /* d = 2,4,8; use a grayscale output colormap */

            ncolors = 1 << d;

            cmaplen = ncolors * sizeof(RGBA_QUAD);

            heapcm = 1;

            cta = (l_uint8 *)LEPT_CALLOC(cmaplen, 1);

            stepsize = 255 / (ncolors - 1);

            for (i = 0, val = 0, pquad = (RGBA_QUAD *)cta;

                 i < ncolors;

                 i++, val += stepsize, pquad++) {

                pquad->blue = pquad->green = pquad->red = val;

                pquad->alpha = 255;  /* opaque */

            }

        }

    }

#if DEBUG

    if (pixGetColormap(pix) != NULL) {

        l_uint8  *pcmptr;

        pcmptr = (l_uint8 *)pixGetColormap(pix)->array;

        lept_stderr("Pix colormap[0] = %c%c%c%d\n",

                    pcmptr[0], pcmptr[1], pcmptr[2], pcmptr[3]);

        lept_stderr("Pix colormap[1] = %c%c%c%d\n",

                    pcmptr[4], pcmptr[5], pcmptr[6], pcmptr[7]);

    }

#endif  /* DEBUG */

    offbytes = BMP_FHBYTES + BMP_IHBYTES + cmaplen;

    fsize = offbytes + fimagebytes;

    fdata = (l_uint8 *)LEPT_CALLOC(fsize, 1);

    *pfdata = fdata;

    *pfsize = fsize;

        /* Write little-endian file header data */

    bmpfh = (BMP_FH *)fdata;

    bmpfh->bfType[0] = (l_uint8)(BMP_ID >> 0);

    bmpfh->bfType[1] = (l_uint8)(BMP_ID >> 8);

    bmpfh->bfSize[0] = (l_uint8)(fsize >>  0);

    bmpfh->bfSize[1] = (l_uint8)(fsize >>  8);

    bmpfh->bfSize[2] = (l_uint8)(fsize >> 16);

    bmpfh->bfSize[3] = (l_uint8)(fsize >> 24);

    bmpfh->bfOffBits[0] = (l_uint8)(offbytes >>  0);

    bmpfh->bfOffBits[1] = (l_uint8)(offbytes >>  8);

    bmpfh->bfOffBits[2] = (l_uint8)(offbytes >> 16);

    bmpfh->bfOffBits[3] = (l_uint8)(offbytes >> 24);

        /* Convert to little-endian and write the info header data */

#if defined(__GNUC__)

    bmph = (BMP_HEADER *)bmpfh;

#else

    bmpih = (BMP_IH *)(fdata + BMP_FHBYTES);

#endif

    bmpih->biSize = convertOnBigEnd32(BMP_IHBYTES);

    bmpih->biWidth = convertOnBigEnd32(w);

    bmpih->biHeight = convertOnBigEnd32(h);

    bmpih->biPlanes = convertOnBigEnd16(1);

    bmpih->biBitCount = convertOnBigEnd16(fdepth);

    bmpih->biSizeImage = convertOnBigEnd32(fimagebytes);

    bmpih->biXPelsPerMeter = convertOnBigEnd32(xres);

    bmpih->biYPelsPerMeter = convertOnBigEnd32(yres);

    bmpih->biClrUsed = convertOnBigEnd32(ncolors);

    bmpih->biClrImportant = convertOnBigEnd32(ncolors);

        /* Copy the colormap data and free the cta if necessary */

    if (ncolors > 0) {

        memcpy(fdata + BMP_FHBYTES + BMP_IHBYTES, cta, cmaplen);

        if (heapcm) LEPT_FREE(cta);

    }

        /* When you write a binary image with a colormap

         * that sets BLACK to 0, you must invert the data */

    if (fdepth == 1 && cmap && ((l_uint8 *)(cmap->array))[0] == 0x0) {

        pixInvert(pix, pix);

    }

        /* An endian byte swap is also required */

    pixEndianByteSwap(pix);

        /* Transfer the image data.  Image origin for bmp is at lower right. */

    fmdata = fdata + offbytes;

    if (fdepth != 24 && fdepth != 32) {   /* typ 1 or 8 bpp */

        data = (l_uint8 *)pixGetData(pix) + pixBpl * (h - 1);

        for (i = 0; i < h; i++) {

            memcpy(fmdata, data, fBpl);

            data -= pixBpl;

            fmdata += fBpl;

        }

    } else {  /* 32 bpp pix; 24 bpp or 32 bpp file

             *  See the comments in pixReadStreamBmp() to

             *  understand the logic behind the pixel ordering below.

             *  Note that we have again done an endian swap on

             *  little endian machines before arriving here, so that

             *  the bytes are ordered on both platforms as:

             *           Red        Green        Blue         --

             *      |-----------|------------|-----------|-----------|

             *

             *  For writing an spp == 4 file, the code below shows where

             *  the alpha component is written to file in each pixel.

             */

        extrabytes = fBpl - spp * w;

        line = pixGetData(pix) + pixWpl * (h - 1);

        for (i = 0; i < h; i++) {

            for (j = 0; j < w; j++) {

                pword = line + j;

                pel[2] = *((l_uint8 *)pword + COLOR_RED);

                pel[1] = *((l_uint8 *)pword + COLOR_GREEN);

                pel[0] = *((l_uint8 *)pword + COLOR_BLUE);

                if (spp == 4)

                    pel[3] = *((l_uint8 *)pword + L_ALPHA_CHANNEL);

                memcpy(fmdata, &pel, spp);

                fmdata += spp;

            }

            if (extrabytes) {

                for (k = 0; k < extrabytes; k++) {

                    memcpy(fmdata, &pel, 1);

                    fmdata++;

                }

            }

            line -= pixWpl;

        }

    }

    pixDestroy(&pix);

    return 0;

}

/* --------------------------------------------*/

#endif  /* USE_BMPIO */