Am 02.06.2014 12:09, schrieb Timon Gehr:
On 06/02/2014 09:06 AM, dennis luehring wrote:
i want to port this C++ code to good/clean D and have no real idea how
to start
contains 2 templates - a slice like and a binary reader for an slice
main idea was to copy the immutablity of the slice data to the reader
http://pastebin.com/XX2yhm8D
the example compiles fine with http://gcc.godbolt.org/, clang version
3.4.1 and compiler-options: -O2 -std=c++11
the slice_T template - could be maybe reduce down to an normal D slice
but i want to control the slice (im)mutability - so maybe there is still
a need for the slice_T thing
i don't know if the binary reader read_ref method should be written
totaly different in D
any tips, ideas?
If the following is not already what you were looking for, it should get
you started. (But note that the interface provided by BinaryReader is
unsafe: It may invent pointers. You might want to add template
constraints that would at least allow the implementation to be @trusted.)
template CopyQualifiers(S,T){
import std.traits;
static if(is(S==const)) alias T1=const(Unqual!T);
else alias T1=Unqual!T;
static if(is(S==immutable)) alias T2=immutable(T1);
else alias T2=T1;
static if(is(S==inout)) alias T3=inout(T2);
else alias T3=T2;
static if(is(S==shared)) alias CopyQualifiers=shared(T3);
else alias CopyQualifiers=T3;
}
struct BinaryReader(T){
@disable this();
this(T[] slice){ this.slice=slice; }
size_t left()const{ return slice.length - offset; }
bool enoughSpaceLeft(size_t size)const{ return size <= left(); }
ref readRef(V)(){
if(!enoughSpaceLeft(V.sizeof)) throw new Exception("1");
auto off=offset;
offset+=V.sizeof;
return *cast(CopyQualifiers!(T,V)*)(slice.ptr+off);
}
auto readValue(V)(){ return readRef!V(); }
private:
T[] slice;
size_t offset=0;
}
auto binaryReader(T)(T[] slice){ return BinaryReader!T(slice); }
void main(){
import std.stdio;
try{
auto testData = "THIS IS BINARY TEST DATA"; // no comment
auto stream = binaryReader(testData);
static assert(is(typeof(stream.readRef!uint())==immutable));
(ref ref_){
auto value = stream.readValue!uint();
}(stream.readRef!uint());
}catch(Exception e){
writeln("exception error: ",e.msg);
}catch{
writeln("exception unknown");
}
}
seems to be a good start - how would you implement such slice/reader
thing in idiomatic D style - the same?
