Add support for encoding/decoding custom types

protobuf_serialization.nim

@@ -70,6 +70,10 @@ template increaseBytesRead(amount = 1) =
     if (bytesRead > numBytesToRead.get()).unlikely:
       raise newException(Exception, &"Number of bytes read ({bytesRead}) exceeded bytes requested ({numBytesToRead})")
 
+proc encodeField*[T: not AnyProtoType](protobuf: var ProtoBuffer, value: T) {.inline.}
+proc encodeField*[T: not AnyProtoType](protobuf: var ProtoBuffer, fieldNum: int, value: T) {.inline.}
+proc encodeField[T: not AnyProtoType](stream: OutputStreamVar, fieldNum: int, value: T) {.inline.}
+
 proc put(stream: OutputStreamVar, value: SomeVarint) {.inline.} =
   when value is enum:
     var value = cast[type(ord(value))](value)
@@ -153,6 +157,16 @@ proc encodeField*(protobuf: var ProtoBuffer, value: AnyProtoType) {.inline.} =
   protobuf.encodeField(protobuf.fieldNum, value)
   inc protobuf.fieldNum
 
+proc encodeField[T: not AnyProtoType](stream: OutputStreamVar, fieldNum: int, value: T) {.inline.} =
+  stream.encodeField(fieldNum, value.toBytes)
+
+proc encodeField*[T: not AnyProtoType](protobuf: var ProtoBuffer, fieldNum: int, value: T) {.inline.} =
+  protobuf.outstream.encodeField(fieldNum, value.toBytes)
+
+proc encodeField*[T: not AnyProtoType](protobuf: var ProtoBuffer, value: T) {.inline.} =
+  protobuf.encodeField(protobuf.fieldNum, value.toBytes)
+  inc protobuf.fieldNum
+
 proc get*[T: SomeFixed](
   bytes: var seq[byte],
   ty: typedesc[T],
@@ -276,6 +290,24 @@ proc decodeField*[T: object](
   numBytesToRead = none(int)
 ): ProtoField[T] {.inline.}
 
+proc decodeField*[T: not AnyProtoType](
+  bytes: var seq[byte],
+  ty: typedesc[T],
+  outOffset: var int,
+  outBytesProcessed: var int,
+  numBytesToRead = none(int)
+): ProtoField[T] {.inline.} =
+
+  var bytesRead = 0
+
+  checkType(bytes[outOffset], seq[byte], outOffset)
+
+  result.index = fieldNumber(bytes[outOffset])
+  increaseBytesRead()
+
+  var value = bytes.get(seq[byte], outOffset, outBytesProcessed, numBytesToRead)
+  result.value = value.to(T)
+
 macro setField(obj: typed, fieldNum: int, offset: int, bytesProcessed: int, bytesToRead: Option[int], value: untyped): untyped =
   let typeFields = obj.getTypeInst.getType
 

tests/test_serialization.nim

@@ -6,7 +6,7 @@ import protobuf_serialization
 type
   MyEnum = enum
     ME1, ME2, ME3
-type
+
   Test1 = object
     a: uint
     b: string
@@ -18,6 +18,30 @@ type
     i: Test1
     j: string
     k: bool
+    l: MyInt
+
+  MyInt = distinct int
+
+proc to*(bytes: var seq[byte], ty: typedesc[MyInt]): MyInt =
+
+  var value: int
+
+  var shiftAmount = 0
+
+  for i in 0 ..< len(bytes):
+    value += int(bytes[i]) shl shiftAmount
+    shiftAmount += 8
+
+  result = MyInt(value)
+
+proc toBytes*(value: MyInt): seq[byte] =
+  var value = value.int
+
+  while value > 0:
+    result.add byte(value and 0b1111_1111)
+    value = value shr 8
+
+proc `==`(a, b: MyInt): bool {.borrow.}
 
 suite "Test Varint Encoding":
   test "Can encode/decode enum field":
@@ -55,6 +79,21 @@ suite "Test Varint Encoding":
     assert decoded.value == num
     assert decoded.index == 1
 
+  test "Can encode/decode distinct number field":
+    var proto = newProtoBuffer()
+    let num = 114151.MyInt
+    var bytesProcessed: int
+
+    proto.encodeField(num)
+
+    var output = proto.output
+    assert output == @[10.byte, 3, 231, 189, 1]
+
+    var offset = 0
+    let decoded = decodeField(output, MyInt, offset, bytesProcessed)
+    assert decoded.value.int == num.int
+    assert decoded.index == 1
+
   test "Can encode/decode float32 number field":
     var proto = newProtoBuffer()
     let num = float32(1234.164423)
@@ -180,7 +219,7 @@ suite "Test Varint Encoding":
   test "Can encode/decode object field":
     var proto = newProtoBuffer()
 
-    let obj = Test3(g: 300, h: 200, i: Test1(a: 100, b: "this is a test", c: 'H'), j: "testing", k: true)
+    let obj = Test3(g: 300, h: 200, i: Test1(a: 100, b: "this is a test", c: 'H'), j: "testing", k: true, l: 124521.MyInt)
 
     proto.encodeField(obj)
     var offset, bytesProcessed: int
@@ -193,7 +232,7 @@ suite "Test Varint Encoding":
   test "Can encode/decode object":
     var proto = newProtoBuffer()
 
-    let obj = Test3(g: 300, h: 200, i: Test1(a: 100, b: "this is a test", c: 'H'), j: "testing", k: true)
+    let obj = Test3(g: 300, h: 200, i: Test1(a: 100, b: "this is a test", c: 'H'), j: "testing", k: true, l: 124521.MyInt)
 
     proto.encode(obj)
     var output = proto.output
@@ -203,7 +242,8 @@ suite "Test Varint Encoding":
   test "Can encode/decode out of order object":
     var proto = newProtoBuffer()
 
-    let obj = Test3(g: 400, h: 100, i: Test1(a: 100, b: "this is a test", c: 'H'), j: "testing", k: true)
+    let obj = Test3(g: 400, h: 100, i: Test1(a: 100, b: "this is a test", c: 'H'), j: "testing", k: true, l: 14514.MyInt)
+    proto.encodeField(6, 14514.MyInt)
     proto.encodeField(2, 100)
     proto.encodeField(4, "testing")
     proto.encodeField(1, 400)