Merge pull request #159 from jsams/rdata_single

Add support for Rdata single format (.rds files)

Author: timholy

src/registry.jl

@@ -18,6 +18,16 @@ end
 
 add_format(format"RData", detect_rdata, [".rda", ".RData", ".rdata"], [:RData, LOAD])
 
+function detect_rdata_single(io)
+    seekstart(io)
+    res = read(io, UInt8) in (UInt8('A'), UInt8('B'), UInt8('X')) &&
+        (c = read(io, UInt8); c == UInt8('\n') || (c == UInt8('\r') && read(io, UInt8) == UInt8('\n')))
+    seekstart(io)
+    return res
+end
+
+add_format(format"RDataSingle", detect_rdata_single, [".rds"], [:RData, LOAD])
+
 add_format(format"CSV", (), [".csv"], [:CSVFiles])
 add_format(format"TSV", (), [".tsv"], [:CSVFiles])
 add_format(format"Feather", "FEA1", [".feather"], [:FeatherFiles])

test/files/minimal_ascii.rds

@@ -0,0 +1,40 @@
+A
+2
+197634
+131840
+787
+1
+14
+2
+1.1
+2.2
+1026
+1
+262153
+5
+names
+16
+1
+262153
+3
+num
+1026
+1
+262153
+9
+row.names
+13
+2
+NA
+-2
+1026
+1
+262153
+5
+class
+16
+1
+262153
+10
+data.frame
+254

test/query.jl

@@ -332,6 +332,16 @@ end
         @test (position(io) in (5, 6))
     end
 end
+@testset "RDS detection" begin
+    q = query(joinpath(file_dir, "minimal_ascii.rds"))
+    @test typeof(q) == File{format"RDataSingle"}
+    open(q) do io
+        @test position(io) == 0
+        @test FileIO.detect_rdata_single(io)
+        # need to seek to beginning of file where data structure starts
+        @test position(io)  == 0
+    end
+end
 @testset "Format with function for magic bytes" begin
     add_format(format"FUNCTION_FOR_MAGIC_BYTES", x -> 0x00, ".wav", [:WAV])
     del_format(format"FUNCTION_FOR_MAGIC_BYTES")