From 0cc28b667063b4565859195800da5cf41672ddbc Mon Sep 17 00:00:00 2001
From: Dmitriy Ryajov <dryajov@gmail.com>
Date: Sat, 26 Mar 2022 13:57:21 -0600
Subject: [PATCH] comments, misc

---
 leopard/leopard.nim   | 17 +++++++++++------
 tests/testleopard.nim |  2 +-
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/leopard/leopard.nim b/leopard/leopard.nim
index d236c56..ae9c8b8 100644
--- a/leopard/leopard.nim
+++ b/leopard/leopard.nim
@@ -105,6 +105,8 @@ func decode*(
   for i in 0..<self.decodeBufferCount:
     zeroMem(self.decodeBufferPtr[i], self.bufSize)
 
+  # this is needed because erasures are identified
+  # with `nil` pointers
   var
     dataPtr = newSeq[LeoBufferPtr](data.len)
     parityPtr = newSeq[LeoBufferPtr](self.workBufferCount)
@@ -147,23 +149,26 @@ func decode*(
 func free*(self: var Leo) =
   if self.workBufferPtr.len > 0:
     for i, p in self.workBufferPtr:
-      p.leoFree()
-      self.workBufferPtr[i] = nil
+      if not isNil(p):
+        p.leoFree()
+        self.workBufferPtr[i] = nil
 
     self.workBufferPtr.setLen(0)
 
   if self.dataBufferPtr.len > 0:
     for i, p in self.dataBufferPtr:
-      p.leoFree()
-      self.dataBufferPtr[i] = nil
+      if not isNil(p):
+        p.leoFree()
+        self.dataBufferPtr[i] = nil
 
     self.dataBufferPtr.setLen(0)
 
   if self.kind == LeoCoderKind.Decoder:
     if self.decodeBufferPtr.len > 0:
       for i, p in self.decodeBufferPtr:
-        p.leoFree()
-        self.decodeBufferPtr[i] = nil
+        if not isNil(p):
+          p.leoFree()
+          self.decodeBufferPtr[i] = nil
       self.decodeBufferPtr.setLen(0)
 
 # TODO: The destructor doesn't behave as
diff --git a/tests/testleopard.nim b/tests/testleopard.nim
index 79d9f9f..8795e93 100644
--- a/tests/testleopard.nim
+++ b/tests/testleopard.nim
@@ -43,4 +43,4 @@ suite "Leopard":
       check recovered[1] == data2
     finally:
       encoder.free()
-      decoder.free()
\ No newline at end of file
+      decoder.free()