Fix packed field size calculation

The size was calculated based on wire type. We need to calculate based on
field type because for sint32/sint64 we need to zigzag encode the value
before calculating the size of varint.

2 files changed, 19 insertions, 9 deletions

diff --git a/generator/protoc_gen_nim.nim b/generator/protoc_gen_nim.nim
index d371859..cec2761 100644
--- a/generator/protoc_gen_nim.nim
+++ b/generator/protoc_gen_nim.nim
@@ -206,6 +206,9 @@ proc wiretypeStr(field: Field): string =
     of FieldDescriptorProtoType.TypeSInt32: result &= "Varint"
     of FieldDescriptorProtoType.TypeSInt64: result &= "Varint"
 
+proc fieldTypeStr(field: Field): string =
+    result = "FieldType." & $field.ftype
+
 proc isKeyword(s: string): bool =
     case s
     of "addr", "and", "as", "asm", "bind", "block", "break", "case", "cast",
@@ -593,7 +596,7 @@ iterator genWriteMessageProc(msg: Message): string =
             if field.packed:
                 yield indent(&"if has{field.name}(message):", 4)
                 yield indent(&"writeTag(stream, {field.number}, WireType.LengthDelimited)", 8)
-                yield indent(&"writeVarint(stream, packedFieldSize(message.{field.name}, {wiretypeStr(field)}))", 8)
+                yield indent(&"writeVarint(stream, packedFieldSize(message.{field.name}, {field.fieldTypeStr}))", 8)
                 yield indent(&"for value in message.{field.name}:", 8)
                 yield indent(&"{writer}(stream, value)", 12)
             else:
@@ -748,7 +751,7 @@ iterator genSizeOfMessageProc(msg: Message): string =
 if has{field.name}(message):
     let
         sizeOfTag = sizeOfUInt32(uint32(makeTag({field.number}, WireType.LengthDelimited)))
-        sizeOfData = packedFieldSize(message.{field.name}, {wiretypeStr(field)})
+        sizeOfData = packedFieldSize(message.{field.name}, {field.fieldTypeStr})
         sizeOfSize = sizeOfUInt64(sizeOfData)
     result = sizeOfTag + sizeOfData + sizeOfSize""", 4)
             else:
diff --git a/src/protobuf/stream.nim b/src/protobuf/stream.nim
index 9d843e6..824ad60 100644
--- a/src/protobuf/stream.nim
+++ b/src/protobuf/stream.nim
@@ -274,17 +274,24 @@ proc sizeOfVarint[T](value: T): uint64 =
         inc(result)
     inc(result)
 
-proc packedFieldSize*[T](values: seq[T], wiretype: WireType): uint64 =
-    case wiretype
-    of WireType.Fixed32:
-        result = uint64(len(values)) * 4
-    of WireType.Fixed64:
+proc packedFieldSize*[T](values: seq[T], fieldtype: FieldType): uint64 =
+    case fieldtype
+    of FieldType.Fixed64, FieldType.SFixed64, FieldType.Double:
         result = uint64(len(values)) * 8
-    of WireType.Varint:
+    of FieldType.Fixed32, FieldType.SFixed32, FieldType.Float:
+        result = uint64(len(values)) * 4
+    of FieldType.Int64, FieldType.UInt64, FieldType.Int32, FieldType.Bool,
+       FieldType.UInt32, FieldType.Enum:
         for value in values:
             result += sizeOfVarint(value)
+    of FieldType.SInt32:
+        for value in values:
+            result += sizeOfVarint(zigzagEncode(int32(value)))
+    of FieldType.SInt64:
+        for value in values:
+            result += sizeOfVarint(zigzagEncode(int64(value)))
     else:
-        raise newException(Exception, "invalid wiretype")
+        raise newException(Exception, "invalid fieldtype")
 
 proc sizeOfString*(s: string): uint64 =
     result = sizeOfVarint(len(s).uint64) + len(s).uint64