/* * Interplay C93 video decoder * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com> * * 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 "codec_internal.h"#include "decode.h" typedef struct C93DecoderContext {    AVFrame *pictures[2];    int currentpic;} C93DecoderContext; typedef enum {    C93_8X8_FROM_PREV  = 0x02,    C93_4X4_FROM_PREV  = 0x06,    C93_4X4_FROM_CURR  = 0x07,    C93_8X8_2COLOR     = 0x08,    C93_4X4_2COLOR     = 0x0A,    C93_4X4_4COLOR_GRP = 0x0B,    C93_4X4_4COLOR     = 0x0D,    C93_NOOP           = 0x0E,    C93_8X8_INTRA      = 0x0F,} C93BlockType; #define WIDTH   320#define HEIGHT  192 #define C93_HAS_PALETTE 0x01#define C93_FIRST_FRAME 0x02 static av_cold int decode_end(AVCodecContext *avctx){    C93DecoderContext * const c93 = avctx->priv_data;     av_frame_free(&c93->pictures[0]);    av_frame_free(&c93->pictures[1]);     return 0;} static av_cold int decode_init(AVCodecContext *avctx){    C93DecoderContext *s = avctx->priv_data;    avctx->pix_fmt = AV_PIX_FMT_PAL8;     s->pictures[0] = av_frame_alloc();    s->pictures[1] = av_frame_alloc();    if (!s->pictures[0] || !s->pictures[1])        return AVERROR(ENOMEM);     return 0;} static inline int copy_block(AVCodecContext *avctx, uint8_t *to,        uint8_t *from, int offset, int height, int stride){    int i;    int width = height;    int from_x = offset % WIDTH;    int from_y = offset / WIDTH;    int overflow = from_x + width - WIDTH;     if (!from) {        /* silently ignoring predictive blocks in first frame */        return 0;    }     if (from_y + height > HEIGHT) {        av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n",               offset);        return AVERROR_INVALIDDATA;    }     if (overflow > 0) {        width -= overflow;        for (i = 0; i < height; i++) {            memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow);        }    }     for (i = 0; i < height; i++) {        memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width);    }     return 0;} static inline void draw_n_color(uint8_t *out, int stride, int width,         int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col){    int x, y;    for (y = 0; y < height; y++) {        if (grps)            cols[0] = grps[3 * (y >> 1)];        for (x = 0; x < width; x++) {            if (grps)                cols[1]= grps[(x >> 1) + 1];            out[x + y*stride] = cols[col & ((1 << bpp) - 1)];            col >>= bpp;        }    }} static int decode_frame(AVCodecContext *avctx, AVFrame *rframe,                        int *got_frame, AVPacket *avpkt){    const uint8_t *buf = avpkt->data;    int buf_size = avpkt->size;    C93DecoderContext * const c93 = avctx->priv_data;    AVFrame * const newpic = c93->pictures[c93->currentpic];    AVFrame * const oldpic = c93->pictures[c93->currentpic^1];    GetByteContext gb;    uint8_t *out;    int ret, i, x, y, b, bt = 0;    ptrdiff_t stride;     if ((ret = ff_set_dimensions(avctx, WIDTH, HEIGHT)) < 0)        return ret;     c93->currentpic ^= 1;     if ((ret = ff_reget_buffer(avctx, newpic, 0)) < 0)        return ret;     stride = newpic->linesize[0];     bytestream2_init(&gb, buf, buf_size);    b = bytestream2_get_byte(&gb);    if (b & C93_FIRST_FRAME) {        newpic->pict_type = AV_PICTURE_TYPE_I;        newpic->flags |= AV_FRAME_FLAG_KEY;    } else {        newpic->pict_type = AV_PICTURE_TYPE_P;        newpic->flags &= ~AV_FRAME_FLAG_KEY;    }     for (y = 0; y < HEIGHT; y += 8) {        out = newpic->data[0] + y * stride;        for (x = 0; x < WIDTH; x += 8) {            uint8_t *copy_from = oldpic->data[0];            uint8_t cols[4], grps[4];            C93BlockType block_type;             if (!bt)                bt = bytestream2_get_byte(&gb);             block_type= bt & 0x0F;            switch (block_type) {            case C93_8X8_FROM_PREV: {                int offset = bytestream2_get_le16(&gb);                if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0)                    return ret;                break;            }             case C93_4X4_FROM_CURR:                copy_from = newpic->data[0];            case C93_4X4_FROM_PREV:                for (int j = 0; j < 8; j += 4) {                    for (i = 0; i < 8; i += 4) {                        int offset = bytestream2_get_le16(&gb);                        int from_x = offset % WIDTH;                        int from_y = offset / WIDTH;                        if (block_type == C93_4X4_FROM_CURR && from_y == y+j &&                            (FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) {                            avpriv_request_sample(avctx, "block overlap %d %d %d %d", from_x, x+i, from_y, y+j);                            return AVERROR_INVALIDDATA;                        }                        if ((ret = copy_block(avctx, &out[j*stride+i],                                              copy_from, offset, 4, stride)) < 0)                            return ret;                    }                }                break;             case C93_8X8_2COLOR:                bytestream2_get_buffer(&gb, cols, 2);                for (i = 0; i < 8; i++) {                    draw_n_color(out + i*stride, stride, 8, 1, 1, cols,                                     NULL, bytestream2_get_byte(&gb));                }                 break;             case C93_4X4_2COLOR:            case C93_4X4_4COLOR:            case C93_4X4_4COLOR_GRP:                for (int j = 0; j < 8; j += 4) {                    for (i = 0; i < 8; i += 4) {                        if (block_type == C93_4X4_2COLOR) {                            bytestream2_get_buffer(&gb, cols, 2);                            draw_n_color(out + i + j*stride, stride, 4, 4,                                    1, cols, NULL, bytestream2_get_le16(&gb));                        } else if (block_type == C93_4X4_4COLOR) {                            bytestream2_get_buffer(&gb, cols, 4);                            draw_n_color(out + i + j*stride, stride, 4, 4,                                    2, cols, NULL, bytestream2_get_le32(&gb));                        } else {                            bytestream2_get_buffer(&gb, grps, 4);                            draw_n_color(out + i + j*stride, stride, 4, 4,                                    1, cols, grps, bytestream2_get_le16(&gb));                        }                    }                }                break;             case C93_NOOP:                break;             case C93_8X8_INTRA:                for (int j = 0; j < 8; j++)                    bytestream2_get_buffer(&gb, out + j*stride, 8);                break;             default:                av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n",                       block_type, x, y);                return AVERROR_INVALIDDATA;            }            bt >>= 4;            out += 8;        }    }     if (b & C93_HAS_PALETTE) {        uint32_t *palette = (uint32_t *) newpic->data[1];        for (i = 0; i < 256; i++) {            palette[i] = 0xFFU << 24 | bytestream2_get_be24(&gb);        }#if FF_API_PALETTE_HAS_CHANGEDFF_DISABLE_DEPRECATION_WARNINGS        newpic->palette_has_changed = 1;FF_ENABLE_DEPRECATION_WARNINGS#endif    } else {        if (oldpic->data[1])            memcpy(newpic->data[1], oldpic->data[1], 256 * 4);    }     if ((ret = av_frame_ref(rframe, newpic)) < 0)        return ret;    *got_frame = 1;     return buf_size;} const FFCodec ff_c93_decoder = {    .p.name         = "c93",    CODEC_LONG_NAME("Interplay C93"),    .p.type         = AVMEDIA_TYPE_VIDEO,    .p.id           = AV_CODEC_ID_C93,    .priv_data_size = sizeof(C93DecoderContext),    .init           = decode_init,    .close          = decode_end,    FF_CODEC_DECODE_CB(decode_frame),    .p.capabilities = AV_CODEC_CAP_DR1,    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,};