From b69fd50df8ec24733cef44cb5772fea69cc1e511 Mon Sep 17 00:00:00 2001
From: Joe Crayne <joe@jerkface.net>
Date: Sun, 29 Dec 2019 03:32:37 -0500
Subject: readnodes.hs: Utility to write nodes in a binary format.

---
 dht/examples/readnodes.hs | 96 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 dht/examples/readnodes.hs

diff --git a/dht/examples/readnodes.hs b/dht/examples/readnodes.hs
new file mode 100644
index 00000000..e4a5b522
--- /dev/null
+++ b/dht/examples/readnodes.hs
@@ -0,0 +1,96 @@
+import Control.Monad
+import qualified Data.ByteArray as BA
+import Data.ByteString (hPutStr,pack)
+import Data.Char
+import Data.Function
+import Data.Int
+import Data.List
+import Data.Maybe
+import Data.Word
+import Foreign.Ptr
+import Foreign.Marshal.Utils
+import Foreign.Storable
+import Network.Tox.NodeId
+import System.Environment
+import System.IO (stdout)
+import Text.Read
+
+-- struct bootstrap_node {
+-- 8   char *address;
+-- 2   bool ipv6;
+-- 2   uint16_t port_udp;
+-- 2   uint16_t port_tcp;
+-- 32  uint8_t key[32];
+-- 2
+-- } bootstrap_nodes[] = {
+
+
+int32_bytes :: Int32 -> IO [Word8]
+int32_bytes = int_bytes
+
+int16_bytes :: Int16 -> IO [Word8]
+int16_bytes i = int_bytes i
+
+int_bytes :: Storable a => a -> IO [Word8]
+int_bytes i = with i $ \p0 ->
+    let p = castPtr p0
+    in foldr (\g r -> g >>= \x -> fmap (x :) r) (return [])
+        $ peekElemOff p `map` [ 0 .. sizeOf i - 1 ]
+
+
+node_bytes :: Int32 -> Int -> String -> NodeInfo -> IO [Word8]
+node_bytes num_nodes a s n = do
+    -- amd64 8 + 2 + 2 + 2 + 32 + 2 = 48
+    --       sizeof(bootstrap_node) = 48
+    -- i386 4 + 2 + 2 + 2 + 32 + 2 = 44
+    --      sizeof(bootstrap_node) = 44
+    bigendian <- (==0) . head <$> int32_bytes 1
+    let sz = sizeOf (0::Int) + 2 + 2 + 2 + 32 + 2
+        base = fromIntegral num_nodes * sz
+        ip6 = case find (==':') s of
+            Just _ | bigendian -> [0,1]
+                   | otherwise -> [1,0]
+            _ -> [0,0]
+        t = [0,0] -- TODO: TCP port
+        nid = nodeId n
+    adr <- int_bytes (base + a)
+    u <- int16_bytes $ fromIntegral $ nodePort n
+    return $ foldr (++) []
+        [ adr                    -- char *address;
+        , ip6                    -- bool ipv6;
+        , u                      -- uint16_t port_udp
+        , t                      -- uint16_t port_tcp
+        , BA.unpack (id2key nid) -- uint8_t key[32];
+        , [0,0]                  -- padding
+        ]
+
+addressString :: NodeInfo -> String
+addressString ni = case show (nodeAddr ni) of
+    '[':xs -> takeWhile (/=']') xs
+    xs     -> takeWhile (/=':') xs
+ where
+    a = show (nodeAddr ni)
+
+main = do
+    args <- getArgs
+    let [ifilename] = args
+    ws <- words <$> readFile ifilename
+    let ns :: [ NodeInfo ]
+        ns = mapMaybe readMaybe ws
+        num_nodes :: Int32
+        num_nodes = fromIntegral $ length ns
+        ptr_size :: Int32
+        ptr_size = fromIntegral $ sizeOf (0 :: Int)
+        ss = map addressString ns
+        as = scanl (\i a -> length a + i + 1) 0 ss
+    let h = stdout
+    nbs <- int32_bytes num_nodes
+    pbs <- int32_bytes ptr_size
+    hPutStr h $ pack $ nbs ++ pbs
+    forM_ (zip3 as ss ns) $ \(a,s,n) -> do
+        bs <- node_bytes num_nodes a s n
+        hPutStr h $ pack bs
+    hPutStr h $ pack $ do
+        adr <- ss
+        map (fromIntegral . ord) adr ++ [0]
+
-- 
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