Adds a modified copy of talk/base to webrtc/base. It is the first step in migrating talk/base to webrtc/base.

BUG=N/A
R=andrew@webrtc.org, wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12199004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6107 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/base/helpers.h

@@ -0,0 +1,56 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_BASE_HELPERS_H_
+#define WEBRTC_BASE_HELPERS_H_
+
+#include <string>
+#include "webrtc/base/basictypes.h"
+
+namespace rtc {
+
+// For testing, we can return predictable data.
+void SetRandomTestMode(bool test);
+
+// Initializes the RNG, and seeds it with the specified entropy.
+bool InitRandom(int seed);
+bool InitRandom(const char* seed, size_t len);
+
+// Generates a (cryptographically) random string of the given length.
+// We generate base64 values so that they will be printable.
+// WARNING: could silently fail. Use the version below instead.
+std::string CreateRandomString(size_t length);
+
+// Generates a (cryptographically) random string of the given length.
+// We generate base64 values so that they will be printable.
+// Return false if the random number generator failed.
+bool CreateRandomString(size_t length, std::string* str);
+
+// Generates a (cryptographically) random string of the given length,
+// with characters from the given table. Return false if the random
+// number generator failed.
+bool CreateRandomString(size_t length, const std::string& table,
+                        std::string* str);
+
+// Generates a random id.
+uint32 CreateRandomId();
+
+// Generates a 64 bit random id.
+uint64 CreateRandomId64();
+
+// Generates a random id > 0.
+uint32 CreateRandomNonZeroId();
+
+// Generates a random double between 0.0 (inclusive) and 1.0 (exclusive).
+double CreateRandomDouble();
+
+}  // namespace rtc
+
+#endif  // WEBRTC_BASE_HELPERS_H_