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/* Linux driver for Philips webcam

   Decompression frontend.

   (C) 1999-2003 Nemosoft Unv. (webcam@smcc.demon.nl)

   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

/*

   This is where the decompression routines register and unregister

   themselves. It also has a decompressor wrapper function.

*/

#include <asm/types.h>

#include "pwc.h"

#include "pwc-uncompress.h"

/* This contains a list of all registered decompressors */

static LIST_HEAD(pwc_decompressor_list);

/* Should the pwc_decompress structure ever change, we increase the

   version number so that we don't get nasty surprises, or can

   dynamically adjust our structure.

 */

const int pwc_decompressor_version = PWC_MAJOR;

/* Add decompressor to list, ignoring duplicates */

void pwc_register_decompressor(struct pwc_decompressor *pwcd)

{

        if (pwc_find_decompressor(pwcd->type) == NULL) {

                Trace(TRACE_PWCX, "Adding decompressor for model %d.\n", pwcd->type);

                list_add_tail(&pwcd->pwcd_list, &pwc_decompressor_list);

        }

}

/* Remove decompressor from list */

void pwc_unregister_decompressor(int type)

{

        struct pwc_decompressor *find;

        find = pwc_find_decompressor(type);

        if (find != NULL) {

                Trace(TRACE_PWCX, "Removing decompressor for model %d.\n", type);

                list_del(&find->pwcd_list);

        }

}

/* Find decompressor in list */

struct pwc_decompressor *pwc_find_decompressor(int type)

{

        struct list_head *tmp;

        struct pwc_decompressor *pwcd;

        list_for_each(tmp, &pwc_decompressor_list) {

                pwcd  = list_entry(tmp, struct pwc_decompressor, pwcd_list);

                if (pwcd->type == type)

                        return pwcd;

        }

        return NULL;

}

int pwc_decompress(struct pwc_device *pdev)

{

        struct pwc_frame_buf *fbuf;

        int n, line, col, stride;

        void *yuv, *image;

        u16 *src;

        u16 *dsty, *dstu, *dstv;

        if (pdev == NULL)

                return -EFAULT;

#if defined(__KERNEL__) && defined(PWC_MAGIC)

        if (pdev->magic != PWC_MAGIC) {

                Err("pwc_decompress(): magic failed.\n");

                return -EFAULT;

        }

#endif

        fbuf = pdev->read_frame;

        if (fbuf == NULL)

                return -EFAULT;

        image = pdev->image_ptr[pdev->fill_image];

        if (!image)

                return -EFAULT;

        yuv = fbuf->data + pdev->frame_header_size;  /* Skip header */

        if (pdev->vbandlength == 0) {

                /* Uncompressed mode. We copy the data into the output buffer,

                   using the viewport size (which may be larger than the image

                   size). Unfortunately we have to do a bit of byte stuffing

                   to get the desired output format/size.

                 */

                        /*

                         * We do some byte shuffling here to go from the

                         * native format to YUV420P.

                         */

                        src = (u16 *)yuv;

                        n = pdev->view.x * pdev->view.y;

                        /* offset in Y plane */

                        stride = pdev->view.x * pdev->offset.y + pdev->offset.x;

                        dsty = (u16 *)(image + stride);

                        /* offsets in U/V planes */

                        stride = pdev->view.x * pdev->offset.y / 4 + pdev->offset.x / 2;

                        dstu = (u16 *)(image + n +         stride);

                        dstv = (u16 *)(image + n + n / 4 + stride);

                        /* increment after each line */

                        stride = (pdev->view.x - pdev->image.x) / 2; /* u16 is 2 bytes */

                        for (line = 0; line < pdev->image.y; line++) {

                                for (col = 0; col < pdev->image.x; col += 4) {

                                        *dsty++ = *src++;

                                        *dsty++ = *src++;

                                        if (line & 1)

                                                *dstv++ = *src++;

                                        else

                                                *dstu++ = *src++;

                                }

                                dsty += stride;

                                if (line & 1)

                                        dstv += (stride >> 1);

                                else

                                        dstu += (stride >> 1);

                        }

        }

        else {

                /* Compressed; the decompressor routines will write the data

                   in planar format immediately.

                 */

                if (pdev->decompressor)

                        pdev->decompressor->decompress(

                                &pdev->image, &pdev->view, &pdev->offset,

                                yuv, image,

                                1,

                                pdev->decompress_data, pdev->vbandlength);

                else

                        return -ENXIO; /* No such device or address: missing decompressor */

        }

        return 0;

}

/* Make sure these functions are available for the decompressor plugin

   both when this code is compiled into the kernel or as as module.

 */

EXPORT_SYMBOL_NOVERS(pwc_decompressor_version);

EXPORT_SYMBOL(pwc_register_decompressor);

EXPORT_SYMBOL(pwc_unregister_decompressor);