App Dreameye manager

[megavolt85]

я вот чего ещё нарыл

Код:

/*
#             (C) 2011 Hans de Goede <hdegoede@redhat.com>

# The compression algorithm has been taken from the v4l1 se401 linux kernel
# driver by Jeroen B. Vreeken (pe1rxq@amsat.org)

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA  02110-1335  USA
*/

#include "libv4lconvert-priv.h"
#include <errno.h>

/* The se401 compression algorithm uses a fixed quant factor, which
   can be configured by setting the high nibble of the SE401_OPERATINGMODE
   feature. This needs to exactly match what is in the SE401 driver! */
#define SE401_QUANT_FACT 8

static void wr_pixel(int p, uint8_t **dest, int pitch, int *x)
{
    int i = *x;

    /* First 3 pixels of each line are absolute */
    if (i < 3) {
        (*dest)[i] = p * SE401_QUANT_FACT;
    } else {
        (*dest)[i] = (*dest)[i - 3] + p * SE401_QUANT_FACT;
    }

    *x += 1;
    if (*x == pitch) {
        *x = 0;
        *dest += pitch;
    }
}

enum decode_state {
    get_len,
    sign_bit,
    other_bits,
};

static int decode_JangGu(const uint8_t *data, int bits, int plen, int pixels,
             uint8_t **dest, int pitch, int *x)
{
    enum decode_state state = get_len;
    int len = 0;
    int value = 0;
    int bitnr;
    int bit;

    while (plen) {
        bitnr = 8;
        while (bitnr && bits) {
            bit = ((*data) >> (bitnr-1))&1;
            switch (state) {
            case get_len:
                if (bit) {
                    len++;
                } else {
                    if (!len) {
                        wr_pixel(0, dest, pitch, x);
                        if (!--pixels)
                            return 0;
                    } else {
                        state = sign_bit;
                        value = 0;
                    }
                }
                break;
            case sign_bit:
                if (bit)
                    value = 0;
                else
                    value = -(1 << len) + 1;
                state = other_bits;
                /* fall through for positive number and
                   len == 1 handling */
            case other_bits:
                len--;
                value += bit << len;
                if (len == 0) {
                    /* Done write pixel and get bit len of
                       the next one */
                    state = get_len;
                    wr_pixel(value, dest, pitch, x);
                    if (!--pixels)
                        return 0;
                }
                break;
            }
            bitnr--;
            bits--;
        }
        data++;
        plen--;
    }
    return -1;
}

int v4lconvert_se401_to_rgb24(struct v4lconvert_data *data,
        const unsigned char *src, int src_size,
        unsigned char *dest, int width, int height)
{
    int in, plen, bits, pixels, info;
    int x = 0, total_pixels = 0;

    for (in = 0; in + 4 < src_size; in += plen) {
        bits   = src[in + 3] + (src[in + 2] << 8);
        pixels = src[in + 1] + ((src[in + 0] & 0x3f) << 8);
        info   = (src[in + 0] & 0xc0) >> 6;
        plen   = ((bits + 47) >> 4) << 1;
        /* Sanity checks */
        if (plen > 1024) {
            V4LCONVERT_ERR("invalid se401 packet len %d", plen);
            goto error;
        }
        if (in + plen > src_size) {
            V4LCONVERT_ERR("incomplete se401 packet");
            goto error;
        }
        if (total_pixels + pixels > width * height) {
            V4LCONVERT_ERR("se401 frame overflow");
            goto error;
        }
        /* info: 0 inter packet, 1 eof, 2 sof, 3 not used */
        if ((in == 0 && info != 2) ||
            (in > 0 && in + plen < src_size && info != 0) ||
            (in + plen == src_size && info != 1)) {
            V4LCONVERT_ERR("invalid se401 frame info value");
            goto error;
        }
        if (decode_JangGu(&src[in + 4], bits, plen, pixels * 3,
                  &dest, width * 3, &x)) {
            V4LCONVERT_ERR("short se401 packet");
            goto error;
        }
        total_pixels += pixels;
    }

    if (in != src_size || total_pixels != width * height) {
        V4LCONVERT_ERR("se401 frame size mismatch");
        goto error;
    }

    return 0;

error:
    errno = EIO;
    return -1;
}