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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/current.h>

#include <asm/types.h>

// #include <linux/sched.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 */

	/* Raw format; that's easy... */

	if (pdev->vpalette == VIDEO_PALETTE_RAW)

	{

		memcpy(image, yuv, pdev->frame_size);

		return 0;

	}

	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.

		 */

		int flags;

                flags = PWCX_FLAG_PLANAR;

                if (pdev->vsize == PSZ_VGA && pdev->vframes == 5 && pdev->vsnapshot)

                	flags |= PWCX_FLAG_BAYER;

		if (pdev->decompressor)

			pdev->decompressor->decompress(

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

				yuv, image,

				flags,

				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);