long long pos;
offset_t pos;
static void put_swf_end_tag(AVFormatContext *s){    SWFContext *swf = s->priv_data;    ByteIOContext *pb = &s->pb;    long long pos;    int tag_len, tag;    pos = url_ftell(pb);    tag_len = pos - swf->tag_pos - 2;    tag = swf->tag;    url_fseek(pb, swf->tag_pos, SEEK_SET);    if (tag & TAG_LONG) {        tag &= ~TAG_LONG;        put_le16(pb, (tag << 6) | 0x3f);        put_le32(pb, tag_len - 4);    } else {        assert(tag_len < 0x3f);        put_le16(pb, (tag << 6) | tag_len);    }    url_fseek(pb, pos, SEEK_SET);}