[NaCl SDK] nacl_io: Fix inet_ntop to be consistent with glibc.

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

+// Copyright 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>
+#include <limits.h>
+
+int inet_aton(const char *cp, struct in_addr *inp) {
+  unsigned int p1 = 0, p2 = 0, p3 = 0, p4 = 0;

[binji, 2014/01/27 19:57:18]

Where did this implementation come from? Did you write it?

[Sam Clegg, 2014/01/27 23:10:15]

Yup.  I wanted to use inet_pton() but that doesn't work except when there are 4
dotted quads.  inet_aton explictly supports the X, X.Y and X.Y.Z cases :(

+  int consumed = 0;
+  int matched = sscanf(cp, "%u.%u.%u.%u%n", &p1, &p2, &p3, &p4,
+                       &consumed);
+
+  if (strlen(cp) == consumed && matched == 4) {
+    if ((p1 | p2 | p3 | p4) <= UCHAR_MAX) {
+      in_addr_t host_order_addr = p1 << 24 | p2 << 16 | p3 << 8 | p4;

[binji, 2014/01/27 19:57:18]

parens around <<? Nicer than having to know operator precedence.

[Sam Clegg, 2014/01/27 23:10:15]

Done.

+      inp->s_addr = htonl(host_order_addr);
+      return 1;
+    }
+  }
+
+  matched = sscanf(cp, "%u.%u.%u%n", &p1, &p2, &p3, &consumed);
+  if (strlen(cp) == consumed && matched == 3) {
+    if ((p1 | p2) <= UCHAR_MAX && p3 <= USHRT_MAX) {
+      in_addr_t host_order_addr = p1 << 24 | p2 << 16 | p3;
+      inp->s_addr = htonl(host_order_addr);
+      return 1;
+    }
+  }
+
+  matched = sscanf(cp, "%u.%u%n", &p1, &p2, &consumed);
+  if (strlen(cp) == consumed && matched == 2) {
+    if (p1 <= UCHAR_MAX && p1 <= 1 << 24) {
+      in_addr_t host_order_addr = p1 << 24 | p2;
+      inp->s_addr = htonl(host_order_addr);
+      return 1;
+    }
+  }
+
+  matched = sscanf(cp, "%u%n", &p1, &consumed);
+  if (strlen(cp) == consumed && matched == 1) {
+    inp->s_addr = htonl(p1);
+    return 1;
+  }
+
+  // Failure
+  return 0;
+}
+
+#endif  // defined(PROVIDES_SOCKET_API) && !defined(__GLIBC__)