make Stream aware of MTU, and implement simplified read function on M…

…TU amount

docs/src/index.md

@@ -51,7 +51,7 @@ channel.gain = 42u"dB"
 channel.sample_rate = 2.1u"MHz"
 
 # Open a (potentially multichannel) stream on this channel
-stream = SoapySDR.Stream(ComplexF32, [channel])
+stream = SoapySDR.Stream([channel])
 SoapySDR.activate!(stream)
 
 # Write out random noise
@@ -70,9 +70,9 @@ channel.gain = 42u"dB"
 channel.sample_rate = 2.1u"MHz"
 
 # Open a (potentially multichannel) stream on this channel
-stream = SoapySDR.Stream(ComplexF32, [channel])
+stream = SoapySDR.Stream([channel])
 SoapySDR.activate!(stream)
 
-# Collect data
-Base.read(stream, 10000)
+# Collect all available samples in the buffer
+Base.read(stream)
 ```

src/highlevel.jl

@@ -256,16 +256,6 @@ function Base.show(io::IO, ::MIME"text/plain", c::Channel)
     end
 end
 
-"""
-    native_stream_format(c::Channel)
-
-Returns the format type and fullscale resolution of the native stream.
-"""
-function native_stream_format(c::Channel)
-    fmt, fullscale = SoapySDRDevice_getNativeStreamFormat(c.device.ptr, c.direction, c.idx)
-    _stream_type_soapy2jl[unsafe_string(fmt)], fullscale
-end
-
 struct ChannelList <: AbstractVector{Channel}
     device::Device
     direction::Direction
@@ -458,21 +448,47 @@ struct FreqSpec{T}
     kwargs::Dict{Any, String}
 end
 
-### Streams
+### Stream Utility Functions
+
+"""
+    stream_formats(::Channel)
+
+Returns the stream formats supported by the device. 
 
+Note: Since Julia is a multiple dispatch and generic language, it is
+preferrable to use `native_stream_format(c::Channel)` for optimal processing throughput.
+Only use this function if non-standard formats such as Complex Int12 and Complex Int4
+are native to the device and not handled by dispatch on `Complex`.
+"""
 function stream_formats(c::Channel)
     slist = StringList(SoapySDRDevice_getStreamFormats(c.device.ptr, c.direction, c.idx)...)
-    map(StreamFormat, slist)
+    map(_stream_map_soapy2jl, slist)
+end
+
+# Internal, reflected in Stream.mtu
+function mtu(d::Device, stream::Ptr{SoapySDRStream})
+    SoapySDRDevice_getStreamMTU(d.ptr, stream)
+end
+
+"""
+    native_stream_format(c::Channel) -> Type, fullscale
+
+Returns the format type and fullscale resolution of the native stream.
+"""
+function native_stream_format(c::Channel)
+    fmt, fullscale = SoapySDRDevice_getNativeStreamFormat(c.device.ptr, c.direction, c.idx)
+    _stream_map_soapy2jl(unsafe_string(fmt)), fullscale
 end
 
 ## Stream
 
 mutable struct Stream{T}
     d::Device
     nchannels::Int
+    mtu::Int
     ptr::Ptr{SoapySDRStream}
     function Stream{T}(d::Device, nchannels::Int, ptr::Ptr{SoapySDRStream}) where {T}
-        this = new{T}(d, nchannels, ptr)
+        this = new{T}(d, nchannels, mtu(d, ptr), ptr)
         finalizer(SoapySDRDevice_closeStream, this)
         return this
     end
@@ -544,6 +560,10 @@ function Base.read(s::Stream{T}, n::Int; kwargs...) where {T}
     SampleBuffer(bufs, flags, timens)
 end
 
+function Base.read(s::Stream; kwargs...)
+    read(s, s.mtu; kwargs...)
+end
+
 function activate!(s::Stream; flags = 0, timens = nothing, numElems=0)
     SoapySDRDevice_activateStream(s.d, s, flags, timens === nothing ? 0 : uconvert(u"ns", timens).val, numElems)
     nothing

test/runtests.jl

@@ -61,6 +61,8 @@ end
     @test typeof(rx_chan) == sd.Channel
     @test typeof(tx_chan) == sd.Channel
 
+    @test sd.native_stream_format(rx_chan)[1] == SoapySDR.ComplexInt{12} #, fullscale
+    @test sd.stream_formats(rx_chan) == [Complex{Int8}, SoapySDR.ComplexInt{12}, Complex{Int16}, ComplexF32]
 
     # Test sensor API
     sensor_list = sd.list_sensors(dev)