Add routine to read a nul-terminated string

src/BDIOmethods.jl

@@ -316,6 +316,32 @@ function BDIO_read(fb::BDIOstream, vdata::Vector, n::Int64 = 0)
     
 end
 
+"""
+    BDIO_read_str(fb::BDIOstream)
+
+Read a nul-terminated string from BDIO file.  
+
+## Arguments
+- `fb`: A BDIOstream type. It must be associated with a file.
+
+## Examples
+```julia-repl
+julia> # Real 1000 floats from the first record of file `randoms.bdio`
+julia> fb = BDIO_open("randoms.bdio", "r")
+julia> BDIO_seek!(fb)
+julia> str = BDIO_read_str(fb)
+```
+"""
+function BDIO_read_str(fb::BDIOstream)
+
+    rpos::Int64 = max(fb.records[fb.ipt].rpos, fb.rwpos)
+    seek(fb.io,rpos)
+    str::String = readuntil(fb.io, '\0')
+    fb.rwpos = position(fb.io)
+
+    return str
+end
+
 """
     BDIO_get_len(fb::BDIOstream)