From 720f1a254daf7c769b226a67b1c5d79524b8ce20 Mon Sep 17 00:00:00 2001
From: Jacek Sieka <jacek@status.im>
Date: Wed, 6 May 2020 15:51:07 +0200
Subject: [PATCH] byteutils: compile-time to/fromBytes (#35)

---
 stew/byteutils.nim       | 14 ++++++++++++--
 tests/test_byteutils.nim |  3 ++-
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/stew/byteutils.nim b/stew/byteutils.nim
index d51c66c..91b08a9 100644
--- a/stew/byteutils.nim
+++ b/stew/byteutils.nim
@@ -145,12 +145,22 @@ func toBytes*(s: string): seq[byte] =
   ## Convert a string to the corresponding byte sequence - since strings in
   ## nim essentially are byte sequences without any particular encoding, this
   ## simply copies the bytes without a null terminator
-  @(s.toOpenArrayByte(0, s.high))
+  when nimvm:
+    var r = newSeq[byte](s.len)
+    for i, c in s:
+      r[i] = cast[byte](c)
+    r
+  else:
+    @(s.toOpenArrayByte(0, s.high))
 
 func fromBytes*(T: type string, v: openArray[byte]): string =
   if v.len > 0:
     result = newString(v.len)
-    copyMem(addr result[0], unsafeAddr v[0], v.len)
+    when nimvm:
+      for i, c in v:
+        result[i] = cast[char](c)
+    else:
+      copyMem(addr result[0], unsafeAddr v[0], v.len)
 
 func `<`*(a, b: openArray[byte]): bool =
   ## Lexicographical compare of two byte arrays
diff --git a/tests/test_byteutils.nim b/tests/test_byteutils.nim
index c304a34..c27b729 100644
--- a/tests/test_byteutils.nim
+++ b/tests/test_byteutils.nim
@@ -99,7 +99,8 @@ suite "Byte utils":
 
       "".toBytes().len() == 0
       string.fromBytes([]) == ""
-
+      @[byte(ord('a'))] == static("a".toBytes())
+      "a" == static(string.fromBytes([byte(ord('a'))]))
   test "slices":
     var a: array[4, byte]
     a[0..<2] = [2'u8, 3]