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log.h
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1 #ifndef __LOG_H__
2 #define __LOG_H__
3 
4 // from here http://stackoverflow.com/questions/5028302/small-logger-class
5 
6 #include <sstream>
7 #include <string>
8 #include <stdio.h>
9 
10 inline std::string NowTime();
11 
12 enum TLogLevel {logEMERGENCY, logALERT, logCRITICAL, logERROR, logWARN, logWARN1, logWARN2, logWARN3, logINFO, logDEBUG};
13 
14 template <typename T>
15 class Log
16 {
17 public:
18  Log();
19  virtual ~Log();
20  std::ostringstream& Get(TLogLevel level = logINFO);
21 public:
22  static TLogLevel& ReportingLevel();
23  static std::string ToString(TLogLevel level);
24  static TLogLevel FromString(const std::string& level);
25 protected:
26  std::ostringstream os;
27 private:
28  Log(const Log&);
29  Log& operator =(const Log&);
30 };
31 
32 template <typename T>
33 Log<T>::Log()
34 {
35 }
36 
37 template <typename T>
38 std::ostringstream& Log<T>::Get(TLogLevel level)
39 {
40  os << "- " << NowTime();
41  os << " " << ToString(level) << ": ";
42  os << std::string(level > logWARN && level <= logWARN3 ? level - logWARN : 0, '\t');
43  return os;
44 }
45 
46 template <typename T>
47 Log<T>::~Log()
48 {
49  os << std::endl;
50  T::Output(os.str());
51 }
52 
53 template <typename T>
54 TLogLevel& Log<T>::ReportingLevel()
55 {
56  static TLogLevel reportingLevel = logERROR;
57  return reportingLevel;
58 }
59 
60 template <typename T>
61 std::string Log<T>::ToString(TLogLevel level)
62 {
63  static const char* const buffer[] = {"EMERGENCY", "ALERT", "CRITICAL", "ERROR", "WARN", "WARN1", "WARN2", "WARN3", "INFO", "DEBUG"};
64  return buffer[level];
65 }
66 
67 template <typename T>
68 TLogLevel Log<T>::FromString(const std::string& level)
69 {
70  if (level == "DEBUG")
71  return logDEBUG;
72  if (level == "INFO")
73  return logINFO;
74  if (level == "WARN3")
75  return logWARN3;
76  if (level == "WARN2")
77  return logWARN2;
78  if (level == "WARN1")
79  return logWARN1;
80  if (level == "WARN")
81  return logWARN;
82  if (level == "ERROR")
83  return logERROR;
84  if (level == "CRITICAL")
85  return logCRITICAL;
86  if (level == "ALERT")
87  return logALERT;
88  if (level == "EMERGENCY")
89  return logEMERGENCY;
90  Log<T>().Get(logWARN) << "Unknown logging level '" << level << "'. Using INFO level as default.";
91  return logINFO;
92 }
93 
94 class Output2FILE
95 {
96 public:
97  static FILE*& Stream();
98  static void Output(const std::string& msg);
99 };
100 
101 inline FILE*& Output2FILE::Stream()
102 {
103  static FILE* pStream = stderr;
104  return pStream;
105 }
106 
107 inline void Output2FILE::Output(const std::string& msg)
108 {
109  FILE* pStream = Stream();
110  if (!pStream)
111  return;
112  fprintf(pStream, "%s", msg.c_str());
113  fflush(pStream);
114 }
115 
116 #if defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
117 # if defined (BUILDING_FILELOG_DLL)
118 # define FILELOG_DECLSPEC __declspec (dllexport)
119 # elif defined (USING_FILELOG_DLL)
120 # define FILELOG_DECLSPEC __declspec (dllimport)
121 # else
122 # define FILELOG_DECLSPEC
123 # endif // BUILDING_DBSIMPLE_DLL
124 #else
125 # define FILELOG_DECLSPEC
126 #endif // _WIN32
127 
128 class FILELOG_DECLSPEC FILELog : public Log<Output2FILE> {};
129 //typedef Log<Output2FILE> FILELog;
130 
131 #ifndef FILELOG_MAX_LEVEL
132 #define FILELOG_MAX_LEVEL logDEBUG
133 #endif
134 
135 #define FILE_LOG(level) \
136  if (level > FILELOG_MAX_LEVEL) ;\
137  else if (level > FILELog::ReportingLevel() || !Output2FILE::Stream()) ; \
138  else FILELog().Get(level)
139 
140 #if defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
141 
142 #include <windows.h>
143 
144 inline std::string NowTime()
145 {
146  const int MAX_LEN = 200;
147  char buffer[MAX_LEN];
148  if (GetTimeFormatA(LOCALE_USER_DEFAULT, 0, 0,
149  "HH':'mm':'ss", buffer, MAX_LEN) == 0)
150  return "Error in NowTime()";
151 
152  char result[100] = {0};
153  static DWORD first = GetTickCount();
154  std::sprintf(result, "%s.%03ld", buffer, (long)(GetTickCount() - first) % 1000);
155  return result;
156 }
157 
158 #else
159 
160 #include <sys/time.h>
161 
162 inline std::string NowTime()
163 {
164  char buffer[11];
165  time_t t;
166  time(&t);
167  tm r = {0};
168  strftime(buffer, sizeof(buffer), "%X", localtime_r(&t, &r));
169  struct timeval tv;
170  gettimeofday(&tv, 0);
171  char result[100] = {0};
172  std::sprintf(result, "%s.%03ld", buffer, (long)tv.tv_usec / 1000);
173  return result;
174 }
175 
176 #endif //WIN32
177 
178 #endif //__LOG_H__