/*

 * BMP image format encoder

 * Copyright (c) 2006, 2007 Michel Bardiaux

 * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>

 *

 * 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

 */

#include "config.h"

#include "libavutil/avassert.h"

#include "libavutil/imgutils_internal.h"

#include "avcodec.h"

#include "bytestream.h"

#include "bmp.h"

#include "codec_internal.h"

#include "encode.h"

static const uint32_t monoblack_pal[] = { 0x000000, 0xFFFFFF };

static const uint32_t rgb565_masks[]  = { 0xF800, 0x07E0, 0x001F };

static const uint32_t rgb444_masks[]  = { 0x0F00, 0x00F0, 0x000F };

static av_cold int bmp_encode_init(AVCodecContext *avctx){

    switch (avctx->pix_fmt) {

    case AV_PIX_FMT_BGRA:

        avctx->bits_per_coded_sample = 32;

        break;

    case AV_PIX_FMT_BGR24:

        avctx->bits_per_coded_sample = 24;

        break;

    case AV_PIX_FMT_RGB555:

    case AV_PIX_FMT_RGB565:

    case AV_PIX_FMT_RGB444:

        avctx->bits_per_coded_sample = 16;

        break;

    case AV_PIX_FMT_RGB8:

    case AV_PIX_FMT_BGR8:

    case AV_PIX_FMT_RGB4_BYTE:

    case AV_PIX_FMT_BGR4_BYTE:

    case AV_PIX_FMT_GRAY8:

    case AV_PIX_FMT_PAL8:

        avctx->bits_per_coded_sample = 8;

        break;

    case AV_PIX_FMT_MONOBLACK:

        avctx->bits_per_coded_sample = 1;

        break;

    }

    return 0;

}

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

                            const AVFrame *pict, int *got_packet)

{

    const AVFrame * const p = pict;

    int n_bytes_image, n_bytes_per_row, n_bytes, i, n, hsize, ret;

    const uint32_t *pal = NULL;

    uint32_t palette256[256];

    int pad_bytes_per_row, pal_entries = 0, compression = BMP_RGB;

    int bit_count = avctx->bits_per_coded_sample;

    const uint8_t *ptr;

    uint8_t *buf;

    switch (avctx->pix_fmt) {

    case AV_PIX_FMT_RGB444:

        compression = BMP_BITFIELDS;

        pal = rgb444_masks; // abuse pal to hold color masks

        pal_entries = 3;

        break;

    case AV_PIX_FMT_RGB565:

        compression = BMP_BITFIELDS;

        pal = rgb565_masks; // abuse pal to hold color masks

        pal_entries = 3;

        break;

    case AV_PIX_FMT_RGB8:

    case AV_PIX_FMT_BGR8:

    case AV_PIX_FMT_RGB4_BYTE:

    case AV_PIX_FMT_BGR4_BYTE:

    case AV_PIX_FMT_GRAY8:

        av_assert1(bit_count == 8);

        avpriv_set_systematic_pal2(palette256, avctx->pix_fmt);

        pal = palette256;

        break;

    case AV_PIX_FMT_PAL8:

        pal = (uint32_t *)p->data[1];

        break;

    case AV_PIX_FMT_MONOBLACK:

        pal = monoblack_pal;

        break;

    }

    if (pal && !pal_entries) pal_entries = 1 << bit_count;

    n_bytes_per_row = ((int64_t)avctx->width * (int64_t)bit_count + 7LL) >> 3LL;

    pad_bytes_per_row = (4 - n_bytes_per_row) & 3;

    n_bytes_image = avctx->height * (n_bytes_per_row + pad_bytes_per_row);

    // STRUCTURE.field refer to the MSVC documentation for BITMAPFILEHEADER

    // and related pages.

#define SIZE_BITMAPFILEHEADER 14

#define SIZE_BITMAPINFOHEADER 40

    hsize = SIZE_BITMAPFILEHEADER + SIZE_BITMAPINFOHEADER + (pal_entries << 2);

    n_bytes = n_bytes_image + hsize;

    if ((ret = ff_get_encode_buffer(avctx, pkt, n_bytes, 0)) < 0)

        return ret;

    buf = pkt->data;

    bytestream_put_byte(&buf, 'B');                   // BITMAPFILEHEADER.bfType

    bytestream_put_byte(&buf, 'M');                   // do.

    bytestream_put_le32(&buf, n_bytes);               // BITMAPFILEHEADER.bfSize

    bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved1

    bytestream_put_le16(&buf, 0);                     // BITMAPFILEHEADER.bfReserved2

    bytestream_put_le32(&buf, hsize);                 // BITMAPFILEHEADER.bfOffBits

    bytestream_put_le32(&buf, SIZE_BITMAPINFOHEADER); // BITMAPINFOHEADER.biSize

    bytestream_put_le32(&buf, avctx->width);          // BITMAPINFOHEADER.biWidth

    bytestream_put_le32(&buf, avctx->height);         // BITMAPINFOHEADER.biHeight

    bytestream_put_le16(&buf, 1);                     // BITMAPINFOHEADER.biPlanes

    bytestream_put_le16(&buf, bit_count);             // BITMAPINFOHEADER.biBitCount

    bytestream_put_le32(&buf, compression);           // BITMAPINFOHEADER.biCompression

    bytestream_put_le32(&buf, n_bytes_image);         // BITMAPINFOHEADER.biSizeImage

    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biXPelsPerMeter

    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biYPelsPerMeter

    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrUsed

    bytestream_put_le32(&buf, 0);                     // BITMAPINFOHEADER.biClrImportant

    for (i = 0; i < pal_entries; i++)

        bytestream_put_le32(&buf, pal[i] & 0xFFFFFF);

    // BMP files are bottom-to-top so we start from the end...

    ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];

    buf = pkt->data + hsize;

    for(i = 0; i < avctx->height; i++) {

        if (HAVE_BIGENDIAN && bit_count == 16) {

            const uint16_t *src = (const uint16_t *) ptr;

            for(n = 0; n < avctx->width; n++)

                AV_WL16(buf + 2 * n, src[n]);

        } else {

            memcpy(buf, ptr, n_bytes_per_row);

        }

        buf += n_bytes_per_row;

        memset(buf, 0, pad_bytes_per_row);

        buf += pad_bytes_per_row;

        ptr -= p->linesize[0]; // ... and go back

    }

    *got_packet = 1;

    return 0;

}

const FFCodec ff_bmp_encoder = {

    .p.name         = "bmp",

    CODEC_LONG_NAME("BMP (Windows and OS/2 bitmap)"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_BMP,

    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,

    .init           = bmp_encode_init,

    FF_CODEC_ENCODE_CB(bmp_encode_frame),

    CODEC_PIXFMTS(AV_PIX_FMT_BGRA, AV_PIX_FMT_BGR24,

                  AV_PIX_FMT_RGB565, AV_PIX_FMT_RGB555, AV_PIX_FMT_RGB444,

                  AV_PIX_FMT_RGB8, AV_PIX_FMT_BGR8, AV_PIX_FMT_RGB4_BYTE,

                  AV_PIX_FMT_BGR4_BYTE, AV_PIX_FMT_GRAY8, AV_PIX_FMT_PAL8,

                  AV_PIX_FMT_MONOBLACK),

};