OW_UUID.cpp

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#include "OW_config.h"
#include "OW_UUID.hpp"
#include "OW_NonRecursiveMutex.hpp"
#include "OW_NonRecursiveMutexLock.hpp"
#include "OW_Types.hpp"
#include "OW_Format.hpp"
#include "OW_CryptographicRandomNumber.hpp"
#include "OW_ExceptionIds.hpp"

#if !defined(OW_WIN32)
#include <sys/time.h> // for gettimeofday
#endif

#include <string.h> // for memcmp
#include <stdlib.h> // for rand
#include <ctype.h> // for isxdigit

namespace OW_NAMESPACE
{

OW_DEFINE_EXCEPTION_WITH_ID(UUID);

namespace {
// typedefs
typedef UInt64 uuid_time_t;
struct uuid_node_t 
{
   unsigned char nodeId[6];
};
struct uuid_state
{
   uuid_time_t timestamp;
   uuid_node_t nodeId;
   UInt16 clockSequence;
};
// static generator state
uuid_state g_state;
NonRecursiveMutex g_guard;

#ifdef OW_WIN32

// FILETIME of Jan 1 1970 00:00:00.
static const unsigned __int64 epoch = 116444736000000000L;

int gettimeofday(struct timeval * tp, int bogusParm)
{
   FILETIME file_time;
   SYSTEMTIME  system_time;
   ULARGE_INTEGER ularge;

   GetSystemTime(&system_time);
   SystemTimeToFileTime(&system_time, &file_time);
   ularge.LowPart = file_time.dwLowDateTime;
   ularge.HighPart = file_time.dwHighDateTime;

   tp->tv_sec = (long) ((ularge.QuadPart - epoch) / 10000000L);
   tp->tv_usec = (long) (system_time.wMilliseconds * 1000);

   return 0;
}
#endif

void getSystemTime(uuid_time_t *uuid_time)
{
   struct timeval tp;
   gettimeofday(&tp, 0);
   // Offset between UUID formatted times and Unix formatted times.
   // UUID UTC base time is October 15, 1582.
   // Unix base time is January 1, 1970.
   *uuid_time = 
      (static_cast<unsigned long long>(tp.tv_sec) * 10000000) + 
      (tp.tv_usec * 10) +
      ((static_cast<unsigned long long>(0x01B21DD2)) << 32) + 
      0x13814000;
}
// these globals are protected by the mutex locked in UUID::UUID()
uuid_time_t timeLast;
UInt16 uuidsThisTick;
bool currentTimeInited = false;
void getCurrentTime(uuid_time_t * timestamp) 
{
   uuid_time_t timeNow;
   if (!currentTimeInited) 
   {
      getSystemTime(&timeLast);
      uuidsThisTick = 0;
      currentTimeInited = true;
   }
   getSystemTime(&timeNow);
   if (timeLast != timeNow) 
   {
      uuidsThisTick = 0;
      timeLast = timeNow;
   }
   else
   {
      uuidsThisTick++;
   }
   // add the count of uuids to low order bits of the clock reading
   *timestamp = timeNow + uuidsThisTick;
}
void getRandomBytes(void* buf, size_t len)
{
   CryptographicRandomNumber rn;
   unsigned char* cp = reinterpret_cast<unsigned char*>(buf);
   for (size_t i = 0; i < len; ++cp, ++i)
   {
      *cp = rn.getNextNumber();
   }
}
// these globals are protected by the mutex locked in UUID::UUID()
unsigned char nodeId[6];
bool nodeIdInitDone = false;
void getNodeIdentifier(uuid_node_t *node) 
{
   // If we ever get a portable (or ported) method of acquiring the MAC
   // address, we should use that.  Until then, we'll just use random
   // numbers.
   if (!nodeIdInitDone)
   {
      getRandomBytes(nodeId, sizeof(nodeId));
      // Set multicast bit, to prevent conflicts with MAC addressses.
      nodeId[0] |= 0x80;
      nodeIdInitDone = true;
   }
   memcpy(node->nodeId, nodeId, sizeof(node->nodeId));
}
inline unsigned char decodeHex(char c)
{
   if (isdigit(c))
   {
      return c - '0';
   }
   else
   {
      c = toupper(c);
      return c - 'A' + 0xA;
   }
}
inline unsigned char fromHexStr(char c1, char c2, const String& uuidStr)
{
   if (!isxdigit(c1) || !isxdigit(c2))
   {
      OW_THROW(UUIDException, Format("Invalid UUID: %1", uuidStr).c_str());
   }
   return (decodeHex(c1) << 4) | decodeHex(c2);
}
inline char toHexHi(unsigned char c)
{
   unsigned char t = c >> 4;
   return t >= 10 ? t - 10 + 'a' : t + '0';
}
inline char toHexLow(unsigned char c)
{
   unsigned char t = c & 0xF;
   return t >= 10 ? t - 10 + 'a' : t + '0';
}
} // end anonymous namespace 
UUID::UUID()
{
   NonRecursiveMutexLock l(g_guard);
   uuid_time_t timestamp;
   getCurrentTime(&timestamp);
   uuid_node_t node;
   getNodeIdentifier(&node);
   uuid_time_t last_time = g_state.timestamp;
   UInt16 clockseq = g_state.clockSequence;
   uuid_node_t last_node = g_state.nodeId;
   // If clock went backwards (can happen if system clock resolution is low), change clockseq
   if (timestamp < last_time)
   {
      ++clockseq;
   }
   // save the state for next time
   g_state.timestamp = last_time;
   g_state.clockSequence = clockseq;
   g_state.nodeId = last_node;
   l.release();
   // stuff fields into the UUID
   // do time_low 
   UInt32 tmp = static_cast<UInt32>(timestamp & 0xFFFFFFFF);
   m_uuid[3] = static_cast<UInt8>(tmp);
   tmp >>= 8;
   m_uuid[2] = static_cast<UInt8>(tmp);
   tmp >>= 8;
   m_uuid[1] = static_cast<UInt8>(tmp);
   tmp >>= 8;
   m_uuid[0] = static_cast<UInt8>(tmp);
   // do time_mid
   tmp = static_cast<UInt16>((timestamp >> 32) & 0xFFFF);
   m_uuid[5] = static_cast<UInt8>(tmp);
   tmp >>= 8;
   m_uuid[4] = static_cast<UInt8>(tmp);
   // do time_hi_and_version
   tmp = static_cast<UInt16>(((timestamp >> 48) & 0x0FFF) | (1 << 12));
   m_uuid[7] = static_cast<UInt8>(tmp);
   tmp >>= 8;
   m_uuid[6] = static_cast<UInt8>(tmp);
   // do clk_seq_low
   tmp = clockseq & 0xFF;
   m_uuid[9] = static_cast<UInt8>(tmp);
   // do clk_seq_hi_res
   tmp = (clockseq & 0x3F00) >> 8 | 0x80;
   m_uuid[8] = static_cast<UInt8>(tmp);
   memcpy(m_uuid+10, &node, 6);
}
UUID::UUID(const String& uuidStr)
{
   const char* s = uuidStr.c_str();
   if (uuidStr.length() != 36 || s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-')
   {
      OW_THROW(UUIDException, Format("Invalid UUID: %1", uuidStr).c_str());
   }
   m_uuid[0] = fromHexStr(s[0], s[1], uuidStr);
   m_uuid[1] = fromHexStr(s[2], s[3], uuidStr);
   m_uuid[2] = fromHexStr(s[4], s[5], uuidStr);
   m_uuid[3] = fromHexStr(s[6], s[7], uuidStr);
   m_uuid[4] = fromHexStr(s[9], s[10], uuidStr);
   m_uuid[5] = fromHexStr(s[11], s[12], uuidStr);
   m_uuid[6] = fromHexStr(s[14], s[15], uuidStr);
   m_uuid[7] = fromHexStr(s[16], s[17], uuidStr);
   m_uuid[8] = fromHexStr(s[19], s[20], uuidStr);
   m_uuid[9] = fromHexStr(s[21], s[22], uuidStr);
   m_uuid[10] = fromHexStr(s[24], s[25], uuidStr);
   m_uuid[11] = fromHexStr(s[26], s[27], uuidStr);
   m_uuid[12] = fromHexStr(s[28], s[29], uuidStr);
   m_uuid[13] = fromHexStr(s[30], s[31], uuidStr);
   m_uuid[14] = fromHexStr(s[32], s[33], uuidStr);
   m_uuid[15] = fromHexStr(s[34], s[35], uuidStr);
}
String 
UUID::toString() const
{
   // This will return a string like this: 
   // 6ba7b810-9dad-11d1-80b4-00c04fd430c8
   const size_t uuidlen = 37;
   char* buf = new char[uuidlen];
   buf[0] = toHexHi(m_uuid[0]); buf[1] = toHexLow(m_uuid[0]);
   buf[2] = toHexHi(m_uuid[1]); buf[3] = toHexLow(m_uuid[1]);
   buf[4] = toHexHi(m_uuid[2]); buf[5] = toHexLow(m_uuid[2]);
   buf[6] = toHexHi(m_uuid[3]); buf[7] = toHexLow(m_uuid[3]);
   buf[8] = '-';
   buf[9] = toHexHi(m_uuid[4]); buf[10] = toHexLow(m_uuid[4]);
   buf[11] = toHexHi(m_uuid[5]); buf[12] = toHexLow(m_uuid[5]);
   buf[13] = '-';
   buf[14] = toHexHi(m_uuid[6]); buf[15] = toHexLow(m_uuid[6]);
   buf[16] = toHexHi(m_uuid[7]); buf[17] = toHexLow(m_uuid[7]);
   buf[18] = '-';
   buf[19] = toHexHi(m_uuid[8]); buf[20] = toHexLow(m_uuid[8]);
   buf[21] = toHexHi(m_uuid[9]); buf[22] = toHexLow(m_uuid[9]);
   buf[23] = '-';
   buf[24] = toHexHi(m_uuid[10]); buf[25] = toHexLow(m_uuid[10]);
   buf[26] = toHexHi(m_uuid[11]); buf[27] = toHexLow(m_uuid[11]);
   buf[28] = toHexHi(m_uuid[12]); buf[29] = toHexLow(m_uuid[12]);
   buf[30] = toHexHi(m_uuid[13]); buf[31] = toHexLow(m_uuid[13]);
   buf[32] = toHexHi(m_uuid[14]); buf[33] = toHexLow(m_uuid[14]);
   buf[34] = toHexHi(m_uuid[15]); buf[35] = toHexLow(m_uuid[15]);
   buf[36] = '\0';

   return String(String::E_TAKE_OWNERSHIP, buf, uuidlen-1);
}
bool operator==(const UUID& x, const UUID& y)
{
   return memcmp(x.m_uuid, y.m_uuid, sizeof(x.m_uuid)) == 0;
}
bool operator<(const UUID& x, const UUID& y)
{
   return memcmp(x.m_uuid, y.m_uuid, sizeof(x.m_uuid)) < 0;
}
bool operator!=(const UUID& x, const UUID& y)
{
   return !(x == y);
}

} // end namespace OW_NAMESPACE

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