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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);