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/*

 * Copyright (c) 1990 James Ashton - Sydney University

 * Copyright (c) 2012 Stefano Sabatini

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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.

 *

 * FFmpeg 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 FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * X-Face encoder, based on libcompface, by James Ashton.

 */

#include "xface.h"

#include "avcodec.h"

#include "internal.h"

typedef struct XFaceContext {

    AVClass *class;

    uint8_t bitmap[XFACE_PIXELS]; ///< image used internally for decoding

    int max_line_len;             ///< max line length for compressed data

    int set_header;               ///< set X-Face header in the output

} XFaceContext;

static int all_same(char *bitmap, int w, int h)

{

    char val, *row;

    int x;

    val = *bitmap;

    while (h--) {

        row = bitmap;

        x = w;

        while (x--)

            if (*(row++) != val)

                return 0;

        bitmap += XFACE_WIDTH;

    }

    return 1;

}

static int all_black(char *bitmap, int w, int h)

{

    if (w > 3) {

        w /= 2;

        h /= 2;

        return (all_black(bitmap, w, h) && all_black(bitmap + w, w, h) &&

                all_black(bitmap + XFACE_WIDTH * h, w, h) &&

                all_black(bitmap + XFACE_WIDTH * h + w, w, h));

    } else {

        /* at least one pixel in the 2x2 grid is non-zero */

        return *bitmap || *(bitmap + 1) ||

               *(bitmap + XFACE_WIDTH) || *(bitmap + XFACE_WIDTH + 1);

    }

}

static int all_white(char *bitmap, int w, int h)

{

    return *bitmap == 0 && all_same(bitmap, w, h);

}

typedef struct {

    const ProbRange *prob_ranges[XFACE_PIXELS*2];

    int prob_ranges_idx;

} ProbRangesQueue;

static inline int pq_push(ProbRangesQueue *pq, const ProbRange *p)

{

    if (pq->prob_ranges_idx >= XFACE_PIXELS * 2 - 1)

        return -1;

    pq->prob_ranges[pq->prob_ranges_idx++] = p;

    return 0;

}

static void push_greys(ProbRangesQueue *pq, char *bitmap, int w, int h)

{

    if (w > 3) {

        w /= 2;

        h /= 2;

        push_greys(pq, bitmap,                       w, h);

        push_greys(pq, bitmap + w,                   w, h);

        push_greys(pq, bitmap + XFACE_WIDTH * h,     w, h);

        push_greys(pq, bitmap + XFACE_WIDTH * h + w, w, h);

    } else {

        const ProbRange *p = ff_xface_probranges_2x2 +

                 *bitmap +

            2 * *(bitmap + 1) +

            4 * *(bitmap + XFACE_WIDTH) +

            8 * *(bitmap + XFACE_WIDTH + 1);

        pq_push(pq, p);

    }

}

static void encode_block(char *bitmap, int w, int h, int level, ProbRangesQueue *pq)

{

    if (all_white(bitmap, w, h)) {

        pq_push(pq, &ff_xface_probranges_per_level[level][XFACE_COLOR_WHITE]);

    } else if (all_black(bitmap, w, h)) {

        pq_push(pq, &ff_xface_probranges_per_level[level][XFACE_COLOR_BLACK]);

        push_greys(pq, bitmap, w, h);

    } else {

        pq_push(pq, &ff_xface_probranges_per_level[level][XFACE_COLOR_GREY]);

        w /= 2;

        h /= 2;

        level++;

        encode_block(bitmap,                       w, h, level, pq);

        encode_block(bitmap + w,                   w, h, level, pq);

        encode_block(bitmap + h * XFACE_WIDTH,     w, h, level, pq);

        encode_block(bitmap + w + h * XFACE_WIDTH, w, h, level, pq);

    }

}

static av_cold int xface_encode_init(AVCodecContext *avctx)

{

    avctx->coded_frame = avcodec_alloc_frame();

    if (!avctx->coded_frame)

        return AVERROR(ENOMEM);

    avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;

    return 0;

}

static void push_integer(BigInt *b, const ProbRange *prange)

{

    uint8_t r;

    ff_big_div(b, prange->range, &r);

    ff_big_mul(b, 0);

    ff_big_add(b, r + prange->offset);

}

static int xface_encode_frame(AVCodecContext *avctx, AVPacket *pkt,

                              const AVFrame *frame, int *got_packet)

{

    XFaceContext *xface = avctx->priv_data;

    ProbRangesQueue pq = {{ 0 }, 0};

    uint8_t bitmap_copy[XFACE_PIXELS];

    BigInt b = {0};

    int i, j, k, ret = 0;

    const uint8_t *buf;

    uint8_t *p;

    char intbuf[XFACE_MAX_DIGITS];

    if (avctx->width || avctx->height) {

        if (avctx->width != XFACE_WIDTH || avctx->height != XFACE_HEIGHT) {

            av_log(avctx, AV_LOG_ERROR,

                   "Size value %dx%d not supported, only accepts a size of %dx%d\n",

                   avctx->width, avctx->height, XFACE_WIDTH, XFACE_HEIGHT);

            return AVERROR(EINVAL);

        }

    }

    avctx->width  = XFACE_WIDTH;

    avctx->height = XFACE_HEIGHT;

    /* convert image from MONOWHITE to 1=black 0=white bitmap */

    buf = frame->data[0];

    i = j = 0;

    do {

        for (k = 0; k < 8; k++)

            xface->bitmap[i++] = (buf[j]>>(7-k))&1;

        if (++j == XFACE_WIDTH/8) {

            buf += frame->linesize[0];

            j = 0;

        }

    } while (i < XFACE_PIXELS);

    /* create a copy of bitmap */

    memcpy(bitmap_copy, xface->bitmap, XFACE_PIXELS);

    ff_xface_generate_face(xface->bitmap, bitmap_copy);

    encode_block(xface->bitmap,                         16, 16, 0, &pq);

    encode_block(xface->bitmap + 16,                    16, 16, 0, &pq);

    encode_block(xface->bitmap + 32,                    16, 16, 0, &pq);

    encode_block(xface->bitmap + XFACE_WIDTH * 16,      16, 16, 0, &pq);

    encode_block(xface->bitmap + XFACE_WIDTH * 16 + 16, 16, 16, 0, &pq);

    encode_block(xface->bitmap + XFACE_WIDTH * 16 + 32, 16, 16, 0, &pq);

    encode_block(xface->bitmap + XFACE_WIDTH * 32,      16, 16, 0, &pq);

    encode_block(xface->bitmap + XFACE_WIDTH * 32 + 16, 16, 16, 0, &pq);

    encode_block(xface->bitmap + XFACE_WIDTH * 32 + 32, 16, 16, 0, &pq);

    while (pq.prob_ranges_idx > 0)

        push_integer(&b, pq.prob_ranges[--pq.prob_ranges_idx]);

    /* write the inverted big integer in b to intbuf */

    i = 0;

    while (b.nb_words) {

        uint8_t r;

        ff_big_div(&b, XFACE_PRINTS, &r);

        intbuf[i++] = r + XFACE_FIRST_PRINT;

    }

    if ((ret = ff_alloc_packet2(avctx, pkt, i+2)) < 0)

        return ret;

    /* revert the number, and close the buffer */

    p = pkt->data;

    while (--i >= 0)

        *(p++) = intbuf[i];

    *(p++) = '\n';

    *(p++) = 0;

    pkt->flags |= AV_PKT_FLAG_KEY;

    *got_packet = 1;

    return 0;

}

static av_cold int xface_encode_close(AVCodecContext *avctx)

{

    av_freep(&avctx->coded_frame);

    return 0;

}

AVCodec ff_xface_encoder = {

    .name           = "xface",

    .long_name      = NULL_IF_CONFIG_SMALL("X-face image"),

    .type           = AVMEDIA_TYPE_VIDEO,

    .id             = AV_CODEC_ID_XFACE,

    .priv_data_size = sizeof(XFaceContext),

    .init           = xface_encode_init,

    .close          = xface_encode_close,

    .encode2        = xface_encode_frame,

    .pix_fmts       = (const enum PixelFormat[]) { AV_PIX_FMT_MONOWHITE, AV_PIX_FMT_NONE },

};