/* * libjingle * Copyright 2004--2005, Google Inc. * * Redistribution and use in source and binary forms, with or without  * modification, are permitted provided that the following conditions are met: * *  1. Redistributions of source code must retain the above copyright notice,  *     this list of conditions and the following disclaimer. *  2. Redistributions in binary form must reproduce the above copyright notice, *     this list of conditions and the following disclaimer in the documentation *     and/or other materials provided with the distribution. *  3. The name of the author may not be used to endorse or promote products  *     derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */#include "helpers.h"#include "time.h"#include <cstdlib>#include <cassert>// TODO: Change this implementation to use OpenSSL's RAND_bytes.  That will//       give cryptographically random values on all platforms.#ifdef WIN32#include <time.h>#include <windows.h>#endifnamespace cricket {static long g_seed = 1L;int GetRandom() {  return ((g_seed = g_seed * 214013L + 2531011L) >> 16) & 0x7fff;}void SetRandomSeed(unsigned long seed){  g_seed = (long)seed;}static bool s_initrandom;void InitRandom(const char *client_unique, size_t len) {  s_initrandom = true;  // Hash this string - unique per client  uint32 hash = 0;  if (client_unique != NULL) {    for (int i = 0; i < (int)len; i++)      hash = ((hash << 2) + hash) + client_unique[i];  }  // Now initialize the seed against a high resolution  // counter#ifdef WIN32  LARGE_INTEGER big;  QueryPerformanceCounter(&big);  SetRandomSeed(big.LowPart ^ hash);#else  SetRandomSeed(Time() ^ hash);#endif}const char BASE64[64] = {  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',  'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',  'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'};// Generates a random string of the given length.  We generate base64 values so// that they will be printable, though that's not necessary.std::string CreateRandomString(int len) {  // Random number generator should of been initialized!  assert(s_initrandom);  if (!s_initrandom)    InitRandom(0, 0);  std::string str;  for (int i = 0; i < len; i++)#if defined(_MSC_VER) && _MSC_VER < 1300    str.insert(str.end(), BASE64[GetRandom() & 63]);#else    str.push_back(BASE64[GetRandom() & 63]);#endif  return str;}uint32 CreateRandomId() {  uint8 b1 = (uint8)(GetRandom() & 255);  uint8 b2 = (uint8)(GetRandom() & 255);  uint8 b3 = (uint8)(GetRandom() & 255);  uint8 b4 = (uint8)(GetRandom() & 255);  return b1 | (b2 << 8) | (b3 << 16) | (b4 << 24);}bool IsBase64Char(char ch) {  return (('A' <= ch) && (ch <= 'Z')) ||         (('a' <= ch) && (ch <= 'z')) ||         (('0' <= ch) && (ch <= '9')) ||         (ch == '+') || (ch == '/');}bool IsBase64Encoded(const std::string& str) {  for (size_t i = 0; i < str.size(); ++i) {    if (!IsBase64Char(str.at(i)))      return false;  }  return true;}} // namespace cricket