From 211c8f1575719ffd0c44c3b878ac7d04c386a6f6 Mon Sep 17 00:00:00 2001
From: Joe Crayne <joe@jerkface.net>
Date: Thu, 30 May 2019 04:28:21 -0400
Subject: Expose ringMask for buffer bounds usage with ffi.

---
 RingBuffer.hs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/RingBuffer.hs b/RingBuffer.hs
index 64b0624..dd8a7f7 100644
--- a/RingBuffer.hs
+++ b/RingBuffer.hs
@@ -37,8 +37,8 @@ newRing sz newBuffer = do
     syncRing r
     return r
 
-syncRing :: RingBuffer u -> IO ()
-syncRing r = do
+ringMask :: RingBuffer u -> IO (Int32 -> [(Int32,Int32)])
+ringMask r = do
     size <- fromIntegral <$> readIORef (rSize r)
     back <- fromIntegral <$> readIORef (rBack r)
     let mask 0   = []
@@ -47,6 +47,11 @@ syncRing r = do
             | otherwise = case cnt + back - size of
                 front | front > cnt -> [(front - cnt,size)]
                       | otherwise   -> [(0,back), (front,cnt - front)]
+    return mask
+
+syncRing :: RingBuffer u -> IO ()
+syncRing r = do
+    mask <- ringMask r
     syncBuffer (rBuffer r) mask
 
 clearRing :: RingBuffer u -> IO ()
-- 
cgit v1.2.3