static int decode_p_block(FourXContext *f, uint16_t *dst, uint16_t *src, int log2w, int log2h, int stride) { const int index = size2index[log2h][log2w]; const int h = 1 << log2h; int code = get_vlc2(&f->gb, block_type_vlc[1 - (f->version > 1)][index].table, BLOCK_TYPE_VLC_BITS, 1); uint16_t *start = (uint16_t *)f->last_picture->data[0]; uint16_t *end = start + stride * (f->avctx->height - h + 1) - (1 << log2w); int ret; if (code < 0 || code > 6 || log2w < 0) return AVERROR_INVALIDDATA; if (code == 0) { src += f->mv[bytestream2_get_byte(&f->g)]; if (start > src || src > end) { av_log(f->avctx, AV_LOG_ERROR, "mv out of pic\n"); return AVERROR_INVALIDDATA; } mcdc(dst, src, log2w, h, stride, 1, 0); } else if (code == 1) { log2h--; if ((ret = decode_p_block(f, dst, src, log2w, log2h, stride)) < 0) return ret; if ((ret = decode_p_block(f, dst + (stride << log2h), src + (stride << log2h), log2w, log2h, stride)) < 0) return ret; } else if (code == 2) { log2w--; if ((ret = decode_p_block(f, dst , src, log2w, log2h, stride)) < 0) return ret; if ((ret = decode_p_block(f, dst + (1 << log2w), src + (1 << log2w), log2w, log2h, stride)) < 0) return ret; } else if (code == 3 && f->version < 2) { if (start > src || src > end) { av_log(f->avctx, AV_LOG_ERROR, "mv out of pic\n"); return AVERROR_INVALIDDATA; } mcdc(dst, src, log2w, h, stride, 1, 0); } else if (code == 4) { src += f->mv[bytestream2_get_byte(&f->g)]; if (start > src || src > end) { av_log(f->avctx, AV_LOG_ERROR, "mv out of pic\n"); return AVERROR_INVALIDDATA; } mcdc(dst, src, log2w, h, stride, 1, bytestream2_get_le16(&f->g2)); } else if (code == 5) { if (start > src || src > end) { av_log(f->avctx, AV_LOG_ERROR, "mv out of pic\n"); return AVERROR_INVALIDDATA; } mcdc(dst, src, log2w, h, stride, 0, bytestream2_get_le16(&f->g2)); } else if (code == 6) { if (log2w) { dst[0] = bytestream2_get_le16(&f->g2); dst[1] = bytestream2_get_le16(&f->g2); } else { dst[0] = bytestream2_get_le16(&f->g2); dst[stride] = bytestream2_get_le16(&f->g2); } } return 0; }