Add more utilities (#4)

[av skip]

src/ZStd.jl

@@ -36,4 +36,27 @@ An integer representing the maximum compression level available.
 const MAX_COMPRESSION = Int(ccall((:ZSTD_maxCLevel, libzstd), Cint, ()))
 
 
+"""
+    maxcompressedsize(srcsize)
+
+Get the maximum compressed size in the worst-case scenario for a given input size.
+"""
+function maxcompressedsize(srcsize::Csize_t)
+    return ccall((:ZSTD_compressBound, libzstd), Csize_t, (Csize_t, ), srcsize)
+end
+
+maxcompressedsize(srcsize::Int) = Int(maxcompressedsize(Csize_t(srcsize)))
+
+
+"""
+    ZStd.ZSTD_VERSION
+
+The version of Zstandard in use.
+"""
+const ZSTD_VERSION = let
+    ver = Int(ccall((:ZSTD_versionNumber, libzstd), Cuint, ()))
+    str = join(match(r"(\d+)(\d{2})(\d{2})$", string(ver)).captures, ".")
+    VersionNumber(str)
+end
+
 end # module

test/runtests.jl

@@ -17,4 +17,11 @@ using Base.Test
         err_txt = sprint(showerror, err)
         @test startswith(err_txt, "ZStd: Error (generic)")
     end
+
+    @test typeof(ZStd.maxcompressedsize(1)) == Int
+    @test ZStd.maxcompressedsize(1) > 0
+    @test typeof(ZStd.maxcompressedsize(UInt(1))) == UInt
+    @test ZStd.maxcompressedsize(UInt(1)) > UInt(0)
+
+    @test ZStd.ZSTD_VERSION == v"1.0.0"
 end