func: void ffio_fill(AVIOContext *s,int b,int count) while ( count > 0 )  int len = ( s -> buf_end - s -> buf_ptr > count ? count : s -> buf_end - s -> buf_ptr ) ; memset ( ( s -> buf_ptr ) , b , len ); s -> buf_ptr += len; if ( s -> buf_ptr >= s -> buf_end )  flush_buffer ( s ); static void flush_buffer(AVIOContext *s) if ( s -> buf_ptr > s -> buffer )  writeout ( s , ( s -> buffer ) , ( s -> buf_ptr - s -> buffer ) ); static void writeout(AVIOContext *s,const uint8_t *data,int len) if ( s -> write_packet && ! s -> error )  int ret = ( s -> write_packet ) ( s -> opaque , ( ( uint8_t * ) data ) , len ) ; if ( ret < 0 )  s -> error = ret; s -> pos += len; if ( s -> update_checksum )  s -> checksum = ( ( s -> update_checksum ) ( s -> checksum , ( s -> checksum_ptr ) , ( s -> buf_ptr - s -> checksum_ptr ) ) ); s -> checksum_ptr = s -> buffer; s -> buf_ptr = s -> buffer; count -= len; 