From c23f4ddf1bd31b0d17dff09ff7a2132854c5f46e Mon Sep 17 00:00:00 2001
From: andri lim <jangko128@gmail.com>
Date: Thu, 7 Jun 2018 22:26:08 +0700
Subject: [PATCH 1/3] add concat operation

---
 ranges/typedranges.nim | 16 ++++++++++++++++
 tests/ttypedranges.nim | 17 +++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/ranges/typedranges.nim b/ranges/typedranges.nim
index 0ff8651..9943b69 100644
--- a/ranges/typedranges.nim
+++ b/ranges/typedranges.nim
@@ -145,3 +145,19 @@ proc `[]=`*[T, U, V](r: MutRange[T], s: HSlice[U, V], v: Range[T]) {.inline.} =
   r[s] = toOpenArray(v)
 
 proc baseAddr*[T](r: Range[T]): ptr T {.inline.} = r.start
+
+template toRange*[T](a: Range[T]): Range[T] = a
+
+proc concat*[T](v: varargs[Range[T], toRange]): seq[T] =
+  var len = 0
+  for c in v: inc(len, c.len)
+  result = newSeq[T](len)
+  len = 0
+  for c in v:
+    copyMem(result[len].addr, c.start, sizeof(T) * c.len)
+    inc(len, c.len)
+
+proc `&`*[T](a, b: Range[T]): seq[T] =
+  result = newSeq[T](a.len + b.len)
+  copyMem(result[0].addr, a.start, sizeof(T) * a.len)
+  copyMem(result[a.len].addr, b.start, sizeof(T) * b.len)
diff --git a/tests/ttypedranges.nim b/tests/ttypedranges.nim
index 3a49424..3fac19c 100644
--- a/tests/ttypedranges.nim
+++ b/tests/ttypedranges.nim
@@ -26,3 +26,20 @@ suite "Typed ranges":
     var z = toRange(@[1, 2, 3, 4])
     check y == z
     check x != z
+
+  test "concat operation":
+    var a = toRange(@[1,2,3])
+    var b = toRange(@[4,5,6])
+    var c = toRange(@[7,8,9])
+    var d = @[1,2,3,4,5,6,7,8,9]
+    var e = @[1,2,3,4,5,6]
+    var f = @[4,5,6,7,8,9]
+    var x = concat(a, b, c)
+    var y = a & b
+    check x == d
+    check y == e
+    var z = concat(b, @[7,8,9])
+    check z == f
+
+    
+

From 39f0a3cd03990cf7ce30ed4607ad73eff4d22fb3 Mon Sep 17 00:00:00 2001
From: andri lim <jangko128@gmail.com>
Date: Fri, 8 Jun 2018 10:07:47 +0700
Subject: [PATCH 2/3] fix concat operation

---
 ranges/typedranges.nim | 20 ++++++++++++++++----
 tests/ttypedranges.nim | 17 ++++++++++++++++-
 2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/ranges/typedranges.nim b/ranges/typedranges.nim
index 9943b69..b33cae4 100644
--- a/ranges/typedranges.nim
+++ b/ranges/typedranges.nim
@@ -1,4 +1,4 @@
-import ./ptr_arith
+import ./ptr_arith, typetraits
 
 const rangesGCHoldEnabled = not defined(rangesDisableGCHold)
 const unsafeAPIEnabled = defined(rangesEnableUnsafeAPI)
@@ -148,16 +148,28 @@ proc baseAddr*[T](r: Range[T]): ptr T {.inline.} = r.start
 
 template toRange*[T](a: Range[T]): Range[T] = a
 
+# this preferred syntax doesn't work
+# see https://github.com/nim-lang/Nim/issues/7995
+#template copyRange[T](dest: seq[T], destOffset: int, src: Range[T]) =
+#  when supportsCopyMem(T):
+
+template copyRange[T](E: typedesc, dest: seq[T], destOffset: int, src: Range[T]) =
+  when supportsCopyMem(E):
+    copyMem(dest[destOffset].unsafeAddr, src.start, sizeof(T) * src.len)
+  else:
+    for i in 0..<src.len:
+      dest[i + destOffset] = src[i]
+
 proc concat*[T](v: varargs[Range[T], toRange]): seq[T] =
   var len = 0
   for c in v: inc(len, c.len)
   result = newSeq[T](len)
   len = 0
   for c in v:
-    copyMem(result[len].addr, c.start, sizeof(T) * c.len)
+    copyRange(T, result, len, c)
     inc(len, c.len)
 
 proc `&`*[T](a, b: Range[T]): seq[T] =
   result = newSeq[T](a.len + b.len)
-  copyMem(result[0].addr, a.start, sizeof(T) * a.len)
-  copyMem(result[a.len].addr, b.start, sizeof(T) * b.len)
+  copyRange(T, result, 0, a)
+  copyRange(T, result, a.len, b)
diff --git a/tests/ttypedranges.nim b/tests/ttypedranges.nim
index 3fac19c..e71e7ef 100644
--- a/tests/ttypedranges.nim
+++ b/tests/ttypedranges.nim
@@ -41,5 +41,20 @@ suite "Typed ranges":
     var z = concat(b, @[7,8,9])
     check z == f
 
-    
+  test "complex types concat operation":
+    type
+      Jaeger = object
+        name: string
+        weight: int
+
+    var A = Jaeger(name: "Gipsy Avenger", weight: 2004)
+    var B = Jaeger(name: "Striker Eureka", weight: 1850)
+    var C = Jaeger(name: "Saber Athena", weight: 1628)
+    var D = Jaeger(name: "Cherno Alpha", weight: 2412)
+
+    var k = toRange(@[A, B])
+    var m = toRange(@[C, D])
+    var n = concat(k, m)
+    check n == @[A, B, C ,D]
+    check n != @[A, B, C ,C]
 

From af939d8ac48f3740e350ff8ee9cb831906791ef4 Mon Sep 17 00:00:00 2001
From: andri lim <jangko128@gmail.com>
Date: Tue, 12 Jun 2018 16:00:45 +0700
Subject: [PATCH 3/3] fix zero length concat

---
 ranges/typedranges.nim | 3 ++-
 tests/ttypedranges.nim | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/ranges/typedranges.nim b/ranges/typedranges.nim
index b33cae4..4d2eb7c 100644
--- a/ranges/typedranges.nim
+++ b/ranges/typedranges.nim
@@ -155,7 +155,8 @@ template toRange*[T](a: Range[T]): Range[T] = a
 
 template copyRange[T](E: typedesc, dest: seq[T], destOffset: int, src: Range[T]) =
   when supportsCopyMem(E):
-    copyMem(dest[destOffset].unsafeAddr, src.start, sizeof(T) * src.len)
+    if dest.len != 0 and src.len != 0:
+      copyMem(dest[destOffset].unsafeAddr, src.start, sizeof(T) * src.len)
   else:
     for i in 0..<src.len:
       dest[i + destOffset] = src[i]
diff --git a/tests/ttypedranges.nim b/tests/ttypedranges.nim
index e71e7ef..ec41609 100644
--- a/tests/ttypedranges.nim
+++ b/tests/ttypedranges.nim
@@ -41,6 +41,11 @@ suite "Typed ranges":
     var z = concat(b, @[7,8,9])
     check z == f
 
+    let u = toRange(newSeq[int](0))
+    let v = toRange(@[3])
+    check concat(u, v) == @[3]
+    check (v & u) == @[3]
+
   test "complex types concat operation":
     type
       Jaeger = object