/*
 * BMP image format decoder
 * Copyright (c) 2005 Mans Rullgard
 *
 * 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 "avcodec.h"
#include "bytestream.h"
#include "bmp.h"
#include "internal.h"
#include "msrledec.h"

static int bmp_decode_frame(AVCodecContext *avctx,
                            void *data, int *got_frame,
                            AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size       = avpkt->size;
    AVFrame *p         = data;
    unsigned int fsize, hsize;
    int width, height;
    unsigned int depth;
    BiCompression comp;
    unsigned int ihsize;
    int i, j, n, linesize, ret;
    uint32_t rgb[3] = {0};
    uint32_t alpha = 0;
    uint8_t *ptr;
    int dsize;
    const uint8_t *buf0 = buf;
    GetByteContext gb;

    if (buf_size < 14) {
        av_log(avctx, AV_LOG_ERROR, "buf size too small (%d)\n", buf_size);
        return AVERROR_INVALIDDATA;
    }

    if (bytestream_get_byte(&buf) != 'B' ||
        bytestream_get_byte(&buf) != 'M') {
        av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
        return AVERROR_INVALIDDATA;
    }

    fsize = bytestream_get_le32(&buf);
    if (buf_size < fsize) {
        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d), trying to decode anyway\n",
               buf_size, fsize);
        fsize = buf_size;
    }

    buf += 2; /* reserved1 */
    buf += 2; /* reserved2 */

    hsize  = bytestream_get_le32(&buf); /* header size */
    ihsize = bytestream_get_le32(&buf); /* more header size */
    if (ihsize + 14 > hsize) {
        av_log(avctx, AV_LOG_ERROR, "invalid header size %d\n", hsize);
        return AVERROR_INVALIDDATA;
    }

    /* sometimes file size is set to some headers size, set a real size in that case */
    if (fsize == 14 || fsize == ihsize + 14)
        fsize = buf_size - 2;

    if (fsize <= hsize) {
        av_log(avctx, AV_LOG_ERROR, "declared file size is less than header size (%d < %d)\n",
               fsize, hsize);
        return AVERROR_INVALIDDATA;
    }

    switch (ihsize) {
    case  40: // windib
    case  56: // windib v3
    case  64: // OS/2 v2
    case 108: // windib v4
    case 124: // windib v5
        width  = bytestream_get_le32(&buf);
        height = bytestream_get_le32(&buf);
        break;
    case  12: // OS/2 v1
        width  = bytestream_get_le16(&buf);
        height = bytestream_get_le16(&buf);
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "unsupported BMP file, patch welcome\n");
        return AVERROR_PATCHWELCOME;
    }

    /* planes */
    if (bytestream_get_le16(&buf) != 1) {
        av_log(avctx, AV_LOG_ERROR, "invalid BMP header\n");
        return AVERROR_INVALIDDATA;
    }

    depth = bytestream_get_le16(&buf);

    if (ihsize >= 40)
        comp = bytestream_get_le32(&buf);
    else
        comp = BMP_RGB;

    if (comp != BMP_RGB && comp != BMP_BITFIELDS && comp != BMP_RLE4 &&
        comp != BMP_RLE8) {
        av_log(avctx, AV_LOG_ERROR, "BMP coding %d not supported\n", comp);
        return AVERROR_INVALIDDATA;
    }

    if (comp == BMP_BITFIELDS) {
        buf += 20;
        rgb[0] = bytestream_get_le32(&buf);
        rgb[1] = bytestream_get_le32(&buf);
        rgb[2] = bytestream_get_le32(&buf);
        alpha = bytestream_get_le32(&buf);
    }

    avctx->width  = width;
    avctx->height = height > 0 ? height : -height;

    avctx->pix_fmt = AV_PIX_FMT_NONE;

    switch (depth) {
    case 32:
        if (comp == BMP_BITFIELDS) {
            if (rgb[0] == 0xFF000000 && rgb[1] == 0x00FF0000 && rgb[2] == 0x0000FF00)
                avctx->pix_fmt = alpha ? AV_PIX_FMT_ABGR : AV_PIX_FMT_0BGR;
            else if (rgb[0] == 0x00FF0000 && rgb[1] == 0x0000FF00 && rgb[2] == 0x000000FF)
                avctx->pix_fmt = alpha ? AV_PIX_FMT_BGRA : AV_PIX_FMT_BGR0;
            else if (rgb[0] == 0x0000FF00 && rgb[1] == 0x00FF0000 && rgb[2] == 0xFF000000)
                avctx->pix_fmt = alpha ? AV_PIX_FMT_ARGB : AV_PIX_FMT_0RGB;
            else if (rgb[0] == 0x000000FF && rgb[1] == 0x0000FF00 && rgb[2] == 0x00FF0000)
                avctx->pix_fmt = alpha ? AV_PIX_FMT_RGBA : AV_PIX_FMT_RGB0;
            else {
                av_log(avctx, AV_LOG_ERROR, "Unknown bitfields %0X %0X %0X\n", rgb[0], rgb[1], rgb[2]);
                return AVERROR(EINVAL);
            }
        } else {
            avctx->pix_fmt = AV_PIX_FMT_BGRA;
        }
        break;
    case 24:
        avctx->pix_fmt = AV_PIX_FMT_BGR24;
        break;
    case 16:
        if (comp == BMP_RGB)
            avctx->pix_fmt = AV_PIX_FMT_RGB555;
        else if (comp == BMP_BITFIELDS) {
            if (rgb[0] == 0xF800 && rgb[1] == 0x07E0 && rgb[2] == 0x001F)
               avctx->pix_fmt = AV_PIX_FMT_RGB565;
            else if (rgb[0] == 0x7C00 && rgb[1] == 0x03E0 && rgb[2] == 0x001F)
               avctx->pix_fmt = AV_PIX_FMT_RGB555;
            else if (rgb[0] == 0x0F00 && rgb[1] == 0x00F0 && rgb[2] == 0x000F)
               avctx->pix_fmt = AV_PIX_FMT_RGB444;
            else {
               av_log(avctx, AV_LOG_ERROR, "Unknown bitfields %0X %0X %0X\n", rgb[0], rgb[1], rgb[2]);
               return AVERROR(EINVAL);
            }
        }
        break;
    case 8:
        if (hsize - ihsize - 14 > 0)
            avctx->pix_fmt = AV_PIX_FMT_PAL8;
        else
            avctx->pix_fmt = AV_PIX_FMT_GRAY8;
        break;
    case 1:
    case 4:
        if (hsize - ihsize - 14 > 0) {
            avctx->pix_fmt = AV_PIX_FMT_PAL8;
        } else {
            av_log(avctx, AV_LOG_ERROR, "Unknown palette for %d-colour BMP\n", 1<<depth);
            return AVERROR_INVALIDDATA;
        }
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "depth %d not supported\n", depth);
        return AVERROR_INVALIDDATA;
    }

    if (avctx->pix_fmt == AV_PIX_FMT_NONE) {
        av_log(avctx, AV_LOG_ERROR, "unsupported pixel format\n");
        return AVERROR_INVALIDDATA;
    }

    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
        return ret;
    p->pict_type = AV_PICTURE_TYPE_I;
    p->key_frame = 1;

    buf   = buf0 + hsize;
    dsize = buf_size - hsize;

    /* Line size in file multiple of 4 */
    n = ((avctx->width * depth + 31) / 8) & ~3;

    if (n * avctx->height > dsize && comp != BMP_RLE4 && comp != BMP_RLE8) {
        av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
               dsize, n * avctx->height);
        return AVERROR_INVALIDDATA;
    }

    // RLE may skip decoding some picture areas, so blank picture before decoding
    if (comp == BMP_RLE4 || comp == BMP_RLE8)
        memset(p->data[0], 0, avctx->height * p->linesize[0]);

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

    if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {
        int colors = 1 << depth;

        memset(p->data[1], 0, 1024);

        if (ihsize >= 36) {
            int t;
            buf = buf0 + 46;
            t   = bytestream_get_le32(&buf);
            if (t < 0 || t > (1 << depth)) {
                av_log(avctx, AV_LOG_ERROR, "Incorrect number of colors - %X for bitdepth %d\n", t, depth);
            } else if (t) {
                colors = t;
            }
        }
        buf = buf0 + 14 + ihsize; //palette location
        // OS/2 bitmap, 3 bytes per palette entry
        if ((hsize-ihsize-14) < (colors << 2)) {
            if ((hsize-ihsize-14) < colors * 3) {
                av_log(avctx, AV_LOG_ERROR, "palette doesn't fit in packet\n");
                return AVERROR_INVALIDDATA;
            }
            for (i = 0; i < colors; i++)
                ((uint32_t*)p->data[1])[i] = (0xFFU<<24) | bytestream_get_le24(&buf);
        } else {
            for (i = 0; i < colors; i++)
                ((uint32_t*)p->data[1])[i] = 0xFFU << 24 | bytestream_get_le32(&buf);
        }
        buf = buf0 + hsize;
    }
    if (comp == BMP_RLE4 || comp == BMP_RLE8) {
        if (height < 0) {
            p->data[0]    +=  p->linesize[0] * (avctx->height - 1);
            p->linesize[0] = -p->linesize[0];
        }
        bytestream2_init(&gb, buf, dsize);
        ff_msrle_decode(avctx, (AVPicture*)p, depth, &gb);
        if (height < 0) {
            p->data[0]    +=  p->linesize[0] * (avctx->height - 1);
            p->linesize[0] = -p->linesize[0];
        }
    } else {
        switch (depth) {
        case 1:
            for (i = 0; i < avctx->height; i++) {
                int j;
                for (j = 0; j < n; j++) {
                    ptr[j*8+0] =  buf[j] >> 7;
                    ptr[j*8+1] = (buf[j] >> 6) & 1;
                    ptr[j*8+2] = (buf[j] >> 5) & 1;
                    ptr[j*8+3] = (buf[j] >> 4) & 1;
                    ptr[j*8+4] = (buf[j] >> 3) & 1;
                    ptr[j*8+5] = (buf[j] >> 2) & 1;
                    ptr[j*8+6] = (buf[j] >> 1) & 1;
                    ptr[j*8+7] =  buf[j]       & 1;
                }
                buf += n;
                ptr += linesize;
            }
            break;
        case 8:
        case 24:
        case 32:
            for (i = 0; i < avctx->height; i++) {
                memcpy(ptr, buf, n);
                buf += n;
                ptr += linesize;
            }
            break;
        case 4:
            for (i = 0; i < avctx->height; i++) {
                int j;
                for (j = 0; j < n; j++) {
                    ptr[j*2+0] = (buf[j] >> 4) & 0xF;
                    ptr[j*2+1] = buf[j] & 0xF;
                }
                buf += n;
                ptr += linesize;
            }
            break;
        case 16:
            for (i = 0; i < avctx->height; i++) {
                const uint16_t *src = (const uint16_t *) buf;
                uint16_t *dst       = (uint16_t *) ptr;

                for (j = 0; j < avctx->width; j++)
                    *dst++ = av_le2ne16(*src++);

                buf += n;
                ptr += linesize;
            }
            break;
        default:
            av_log(avctx, AV_LOG_ERROR, "BMP decoder is broken\n");
            return AVERROR_INVALIDDATA;
        }
    }

    *got_frame = 1;

    return buf_size;
}

AVCodec ff_bmp_decoder = {
    .name           = "bmp",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_BMP,
    .decode         = bmp_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
    .long_name      = NULL_IF_CONFIG_SMALL("BMP (Windows and OS/2 bitmap)"),
};