Avoid loading ws2_32.dll just to get htons() and friends.

crypto/p224.cc

 // Copyright (c) 2012 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.
 
 // This is an implementation of the P224 elliptic curve group. It's written to
 // be short and simple rather than fast, although it's still constant-time.
 //
 // See http://www.imperialviolet.org/2010/12/04/ecc.html ([1]) for background.
 
 #include "crypto/p224.h"
 
 #include <string.h>
 
 #include "base/sys_byteorder.h"
 
+#if defined(OS_WIN)
+// Allow htonl/ntohl to be called without requiring ws2_32.dll to be loaded,
+// which isn't available in Chrome's sandbox. See crbug.com/116591.
+#define ntohl(x) _byteswap_ulong(x)
+#define htonl(x) _byteswap_ulong(x)
+#endif // OS_WIN

[Ryan Sleevi, 2012/03/06 01:56:47]

This is the second or third time I've seen this pattern, which makes me think it
would be better served by updating base/sys_byteorder.h

After all, http://msdn.microsoft.com/en-us/library/a3140177(v=vs.80).aspx

+
+
+
 namespace {
 
 // Field element functions.
 //
 // The field that we're dealing with is ℤ/pℤ where p = 2**224 - 2**96 + 1.
 //
 // Field elements are represented by a FieldElement, which is a typedef to an
 // array of 8 uint32's. The value of a FieldElement, a, is:
 //   a[0] + 2**28·a[1] + 2**56·a[1] + ... + 2**196·a[7]
 //
@@ skipping 643 matching lines @@
   Subtract(&out->y, kP, y);
   Reduce(&out->y);
 
   memset(&out->z, 0, sizeof(out->z));
   out->z[0] = 1;
 }
 
 }  // namespace p224
 
 }  // namespace crypto