Adds htonl, htons, ntohl, and ntohs to newlib

native_client_sdk/src/libraries/nacl_io/syscalls/htonl.c

Index: native_client_sdk/src/libraries/nacl_io/syscalls/htonl.c
diff --git a/native_client_sdk/src/libraries/nacl_io/syscalls/htonl.c b/native_client_sdk/src/libraries/nacl_io/syscalls/htonl.c
new file mode 100644
index 0000000000000000000000000000000000000000..8bf5eaa77fa3f3a5a5bf26445291e1b49b5e5ac2
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io/syscalls/htonl.c
@@ -0,0 +1,23 @@
+/* Copyright (c) 2013 The Chromium Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file. */
+
+#include "nacl_io/ossocket.h"
+
+#if defined(PROVIDES_SOCKET_API) && !defined(__GLIBC__)
+
+#include <string.h>
+
+inline uint32_t htonl(uint32_t hostlong) {
+  uint8_t result_bytes[4];
+  result_bytes[0] = (uint8_t) ((hostlong >> 24) & 0xFF);
+  result_bytes[1] = (uint8_t) ((hostlong >> 16) & 0xFF);
+  result_bytes[2] = (uint8_t) ((hostlong >> 8) & 0xFF);
+  result_bytes[3] = (uint8_t) (hostlong & 0xFF);

[Sam Clegg, 2013/08/08 19:34:44]

This code is endian depend thought right?

I'd rather see a correct implementation here that works
on either endianness.

glibc uses "# if __BYTE_ORDER == __BIG_ENDIAN" (would
need to find a working equivalent on win32 if we ever
compile this library on windows again in the future).

Also, I think we can/should avoid the extra function call
here and just do it using bitwise operators.  This is an 
example from naclports (glibc-compat/include/machine/endian.h):

#define __byte_swap_16(x) \
  ( (((x) & 0xff) << 8) | ((unsigned short)(x) >> 8) )

#define __byte_swap_32(x) \
        ( ((x) << 24) | \
         (((x) << 8) & 0x00ff0000) | \
         (((x) >> 8) & 0x0000ff00) | \
         ((x) >> 24) )

(Although it looks like that final left shift needs to be
masked or cast to unsigned!)

+
+  uint32_t result;
+  memcpy(&result, result_bytes, 4);
+  return result;
+}
+
+#endif  /* defined(PROVIDES_SOCKET_API) && !defined(__GLIBC__) */