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/*
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 * Feeble Files/ScummVM DXA decoder
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 * Copyright (c) 2007 Konstantin Shishkov
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 *
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 */
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/**
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 * @file dxa.c
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 * DXA Video decoder
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 */
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#include <stdio.h>
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#include <stdlib.h>
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#include "common.h"
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#include "avcodec.h"
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#include <zlib.h>
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/*
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 * Decoder context
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 */
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typedef struct DxaDecContext {
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    AVCodecContext *avctx;
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    AVFrame pic, prev;
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    int dsize;
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    uint8_t *decomp_buf;
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    uint32_t pal[256];
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} DxaDecContext;
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static const int shift1[6] = { 0, 8, 8, 8, 4, 4 };
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static const int shift2[6] = { 0, 0, 8, 4, 0, 4 };
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static int decode_13(AVCodecContext *avctx, DxaDecContext *c, uint8_t* dst, uint8_t *src, uint8_t *ref)
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{
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    uint8_t *code, *data, *mv, *msk, *tmp, *tmp2;
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    int i, j, k;
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    int type, x, y, d, d2;
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    int stride = c->pic.linesize[0];
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    uint32_t mask;
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    code = src  + 12;
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    data = code + ((avctx->width * avctx->height) >> 4);
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    mv   = data + AV_RB32(src + 0);
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    msk  = mv   + AV_RB32(src + 4);
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    for(j = 0; j < avctx->height; j += 4){
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        for(i = 0; i < avctx->width; i += 4){
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            tmp  = dst + i;
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            tmp2 = ref + i;
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            type = *code++;
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            switch(type){
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            case 4: // motion compensation
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                x = (*mv) >> 4;    if(x & 8) x = 8 - x;
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                y = (*mv++) & 0xF; if(y & 8) y = 8 - y;
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                tmp2 += x + y*stride;
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            case 0: // skip
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            case 5: // skip in method 12
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                for(y = 0; y < 4; y++){
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                    memcpy(tmp, tmp2, 4);
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                    tmp  += stride;
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                    tmp2 += stride;
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                }
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                break;
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            case 1:  // masked change
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            case 10: // masked change with only half of pixels changed
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            case 11: // cases 10-15 are for method 12 only
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            case 12:
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            case 13:
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            case 14:
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            case 15:
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                if(type == 1){
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                    mask = AV_RB16(msk);
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                    msk += 2;
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                }else{
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                    type -= 10;
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                    mask = ((msk[0] & 0xF0) << shift1[type]) | ((msk[0] & 0xF) << shift2[type]);
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                    msk++;
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                }
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                for(y = 0; y < 4; y++){
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                    for(x = 0; x < 4; x++){
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                        tmp[x] = (mask & 0x8000) ? *data++ : tmp2[x];
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                        mask <<= 1;
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                    }
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                    tmp  += stride;
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                    tmp2 += stride;
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                }
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                break;
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            case 2: // fill block
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                for(y = 0; y < 4; y++){
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                    memset(tmp, data[0], 4);
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                    tmp += stride;
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                }
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                data++;
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                break;
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            case 3: // raw block
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                for(y = 0; y < 4; y++){
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                    memcpy(tmp, data, 4);
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                    data += 4;
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                    tmp  += stride;
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                }
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                break;
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            case 8: // subblocks - method 13 only
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                mask = *msk++;
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                for(k = 0; k < 4; k++){
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                    d  = ((k & 1) << 1) + ((k & 2) * stride);
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                    d2 = ((k & 1) << 1) + ((k & 2) * stride);
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                    tmp2 = ref + i + d2;
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                    switch(mask & 0xC0){
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                    case 0x80: // motion compensation
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                        x = (*mv) >> 4;    if(x & 8) x = 8 - x;
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                        y = (*mv++) & 0xF; if(y & 8) y = 8 - y;
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                        tmp2 += x + y*stride;
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                    case 0x00: // skip
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                        tmp[d + 0         ] = tmp2[0];
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                        tmp[d + 1         ] = tmp2[1];
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                        tmp[d + 0 + stride] = tmp2[0 + stride];
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                        tmp[d + 1 + stride] = tmp2[1 + stride];
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                        break;
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                    case 0x40: // fill
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                        tmp[d + 0         ] = data[0];
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                        tmp[d + 1         ] = data[0];
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                        tmp[d + 0 + stride] = data[0];
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                        tmp[d + 1 + stride] = data[0];
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                        data++;
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                        break;
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                    case 0xC0: // raw
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                        tmp[d + 0         ] = *data++;
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                        tmp[d + 1         ] = *data++;
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                        tmp[d + 0 + stride] = *data++;
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                        tmp[d + 1 + stride] = *data++;
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                        break;
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                    }
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                    mask <<= 2;
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                }
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                break;
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            case 32: // vector quantization - 2 colors
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                mask = AV_RB16(msk);
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                msk += 2;
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                for(y = 0; y < 4; y++){
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                    for(x = 0; x < 4; x++){
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                        tmp[x] = data[mask & 1];
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                        mask >>= 1;
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                    }
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                    tmp  += stride;
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                    tmp2 += stride;
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                }
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                data += 2;
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                break;
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            case 33: // vector quantization - 3 or 4 colors
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            case 34:
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                mask = AV_RB32(msk);
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                msk += 4;
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                for(y = 0; y < 4; y++){
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                    for(x = 0; x < 4; x++){
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                        tmp[x] = data[mask & 3];
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                        mask >>= 2;
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                    }
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                    tmp  += stride;
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                    tmp2 += stride;
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                }
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                data += type - 30;
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                break;
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            default:
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                av_log(avctx, AV_LOG_ERROR, "Unknown opcode %d\n", type);
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                return -1;
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            }
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        }
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        dst += stride * 4;
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        ref += stride * 4;
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    }
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    return 0;
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}
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static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
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{
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    DxaDecContext * const c = avctx->priv_data;
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    uint8_t *outptr, *srcptr, *tmpptr;
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    unsigned long dsize;
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    int i, j, compr;
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    int stride;
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    int orig_buf_size = buf_size;
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    int pc = 0;
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    /* make the palette available on the way out */
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    if(buf[0]=='C' && buf[1]=='M' && buf[2]=='A' && buf[3]=='P'){
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        int r, g, b;
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        buf += 4;
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        for(i = 0; i < 256; i++){
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            r = *buf++;
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            g = *buf++;
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            b = *buf++;
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            c->pal[i] = (r << 16) | (g << 8) | b;
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        }
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        pc = 1;
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        buf_size -= 768+4;
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    }
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    if(avctx->get_buffer(avctx, &c->pic) < 0){
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        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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        return -1;
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    }
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    memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
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    c->pic.palette_has_changed = pc;
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    outptr = c->pic.data[0];
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    srcptr = c->decomp_buf;
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    tmpptr = c->prev.data[0];
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    stride = c->pic.linesize[0];
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    if(buf[0]=='N' && buf[1]=='U' && buf[2]=='L' && buf[3]=='L')
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        compr = -1;
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    else
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        compr = buf[4];
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    dsize = c->dsize;
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    if((compr != 4 && compr != -1) && uncompress(c->decomp_buf, &dsize, buf + 9, buf_size - 9) != Z_OK){
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        av_log(avctx, AV_LOG_ERROR, "Uncompress failed!\n");
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        return -1;
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    }
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    switch(compr){
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    case -1:
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        c->pic.key_frame = 0;
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        c->pic.pict_type = FF_P_TYPE;
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        if(c->prev.data[0])
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            memcpy(c->pic.data[0], c->prev.data[0], c->pic.linesize[0] * avctx->height);
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        else{ // Should happen only when first frame is 'NULL'
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            memset(c->pic.data[0], 0, c->pic.linesize[0] * avctx->height);
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            c->pic.key_frame = 1;
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            c->pic.pict_type = FF_I_TYPE;
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        }
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        break;
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    case 2:
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    case 3:
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    case 4:
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    case 5:
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        c->pic.key_frame = !(compr & 1);
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        c->pic.pict_type = (compr & 1) ? FF_P_TYPE : FF_I_TYPE;
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        for(j = 0; j < avctx->height; j++){
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            if(compr & 1){
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                for(i = 0; i < avctx->width; i++)
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                    outptr[i] = srcptr[i] ^ tmpptr[i];
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                tmpptr += stride;
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            }else
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                memcpy(outptr, srcptr, avctx->width);
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            outptr += stride;
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            srcptr += avctx->width;
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        }
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        break;
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    case 12: // ScummVM coding
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    case 13:
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        c->pic.key_frame = 0;
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        c->pic.pict_type = FF_P_TYPE;
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        decode_13(avctx, c, c->pic.data[0], srcptr, c->prev.data[0]);
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        break;
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    default:
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        av_log(avctx, AV_LOG_ERROR, "Unknown/unsupported compression type %d\n", buf[4]);
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        return -1;
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    }
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    FFSWAP(AVFrame, c->pic, c->prev);
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    if(c->pic.data[0])
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        avctx->release_buffer(avctx, &c->pic);
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    *data_size = sizeof(AVFrame);
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    *(AVFrame*)data = c->prev;
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    /* always report that the buffer was completely consumed */
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    return orig_buf_size;
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}
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static int decode_init(AVCodecContext *avctx)
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{
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    DxaDecContext * const c = avctx->priv_data;
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    c->avctx = avctx;
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    avctx->pix_fmt = PIX_FMT_PAL8;
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    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
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        return -1;
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    }
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    c->dsize = avctx->width * avctx->height * 2;
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    if((c->decomp_buf = av_malloc(c->dsize)) == NULL) {
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        av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
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        return -1;
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    }
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    return 0;
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}
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static int decode_end(AVCodecContext *avctx)
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{
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    DxaDecContext * const c = avctx->priv_data;
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    av_freep(&c->decomp_buf);
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    if(c->prev.data[0])
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        avctx->release_buffer(avctx, &c->prev);
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    if(c->pic.data[0])
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        avctx->release_buffer(avctx, &c->pic);
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    return 0;
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}
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AVCodec dxa_decoder = {
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    "dxa",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_DXA,
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    sizeof(DxaDecContext),
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    decode_init,
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    NULL,
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    decode_end,
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    decode_frame
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};
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