From 61d5cfc37677f2b434d43c06d06695b00e56613b Mon Sep 17 00:00:00 2001
From: Zahary Karadjov <zahary@gmail.com>
Date: Thu, 2 Jul 2020 18:00:39 +0300
Subject: [PATCH] Add array[N, byte].fromHex(string)

---
 stew/byteutils.nim       |  5 +++++
 tests/test_byteutils.nim | 12 ++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/stew/byteutils.nim b/stew/byteutils.nim
index 9f035e3..81911a7 100644
--- a/stew/byteutils.nim
+++ b/stew/byteutils.nim
@@ -83,6 +83,11 @@ func hexToByteArray*[N: static[int]](hexStr: string): array[N, byte]
   ## Read an hex string and store it in a byte array. No "endianness" reordering is done.
   hexToByteArray(hexStr, result)
 
+func fromHex*[N](A: type array[N, byte], hexStr: string): A
+                {.raises: [ValueError, Defect], noInit, inline.}=
+  ## Read an hex string and store it in a byte array. No "endianness" reordering is done.
+  hexToByteArray(hexStr, result)
+
 func hexToPaddedByteArray*[N: static[int]](hexStr: string): array[N, byte]
                                           {.raises: [ValueError, Defect].} =
   ## Read a hex string and store it in a byte array `output`.
diff --git a/tests/test_byteutils.nim b/tests/test_byteutils.nim
index c27b729..cf171d1 100644
--- a/tests/test_byteutils.nim
+++ b/tests/test_byteutils.nim
@@ -36,6 +36,18 @@ suite "Byte utils":
     expect(ValueError): discard hexToByteArray[1]("")
     expect(ValueError): discard hexToByteArray[1]("1")
 
+  test "array.fromHex":
+    let
+      s = "0x12345678"
+      a2 = array[2, byte].fromHex(s)
+      a4 = array[4, byte].fromHex(s)
+
+    check:
+      a2.toHex == "1234"
+      a4.toHex == "12345678"
+
+    expect(ValueError): echo array[5, byte].fromHex(s)
+
   test "toHex":
     check simpleBArray.toHex == "12345678"
     check hexToSeqByte("12345678") == simpleBArray