strptime.c Source File

1 // Copyright 2009 Google Inc.

2 //

3 // Licensed under the Apache License, Version 2.0 (the "License");

4 // you may not use this file except in compliance with the License.

5 // You may obtain a copy of the License at

6 //

7 // http://www.apache.org/licenses/LICENSE-2.0

8 //

9 // Unless required by applicable law or agreed to in writing, software

10 // distributed under the License is distributed on an "AS IS" BASIS,

11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

12 // See the License for the specific language governing permissions and

13 // limitations under the License.

14 

15 #include <time.h>

16 #include <ctype.h>

17 #include <string.h>

18 

19 #ifdef WIN32

20 

21 #include "strptime.h"

22 

23 #undef NULL

24 #define NULL 0

25 

26 // Implement strptime under windows

27 static const char* kWeekFull[] = {

28  "Sunday", "Monday", "Tuesday", "Wednesday",

29  "Thursday", "Friday", "Saturday"

30 };

31 

32 static const char* kWeekAbbr[] = {

33  "Sun", "Mon", "Tue", "Wed",

34  "Thu", "Fri", "Sat"

35 };

36 

37 static const char* kMonthFull[] = {

38  "January", "February", "March", "April", "May", "June",

39  "July", "August", "September", "October", "November", "December"

40 };

41 

42 static const char* kMonthAbbr[] = {

43  "Jan", "Feb", "Mar", "Apr", "May", "Jun",

44  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"

45 };

46 

47 static const char* _parse_num(const char* s, int low, int high, int* value) {

48  const char* p = s;

49  for (*value = 0; *p != NULL && isdigit(*p); ++p) {

50  *value = (*value) * 10 + (int)(*p) - (int)('0');

51  }

52 

53  if (p == s || *value < low || *value > high) return NULL;

54  return p;

55 }

56 

57 static char* _strptime(const char *s, const char *format, struct tm *tm) {

58  int len = 0;

59  int i;

60  while (*format != NULL && *s != NULL) {

61  if (*format != '%') {

62  if (*s != *format) return NULL;

63 

64  ++format;

65  ++s;

66  continue;

67  }

68 

69  ++format;

70  switch (*format) {

71  // weekday name.

72  case 'a':

73  case 'A':

74  tm->tm_wday = -1;

75  for (i = 0; i < 7; ++i) {

76  len = (int)(strlen(kWeekAbbr[i]));

77  if (_strnicmp(kWeekAbbr[i], s, len) == 0) {

78  tm->tm_wday = i;

79  break;

80  }

81 

82  len = (int)(strlen(kWeekFull[i]));

83  if (_strnicmp(kWeekFull[i], s, len) == 0) {

84  tm->tm_wday = i;

85  break;

86  }

87  }

88  if (tm->tm_wday == -1) return NULL;

89  s += len;

90  break;

91 

92  // month name.

93  case 'b':

94  case 'B':

95  case 'h':

96  {

97  int i;

98  tm->tm_mon = -1;

99  for (i = 0; i < 12; ++i) {

100  len = (int)(strlen(kMonthAbbr[i]));

101  if (_strnicmp(kMonthAbbr[i], s, len) == 0) {

102  tm->tm_mon = i;

103  break;

104  }

105 

106  len = (int)(strlen(kMonthFull[i]));

107  if (_strnicmp(kMonthFull[i], s, len) == 0) {

108  tm->tm_mon = i;

109  break;

110  }

111  }

112  if (tm->tm_mon == -1) return NULL;

113  s += len;

114  }

115  break;

116 

117  // month [1, 12].

118  case 'm':

119  s = _parse_num(s, 1, 12, &tm->tm_mon);

120  if (s == NULL) return NULL;

121  --tm->tm_mon;

122  break;

123 

124  // day [1, 31].

125  case 'd':

126  case 'e':

127  s = _parse_num(s, 1, 31, &tm->tm_mday);

128  if (s == NULL) return NULL;

129  break;

130 

131  // hour [0, 23].

132  case 'H':

133  s = _parse_num(s, 0, 23, &tm->tm_hour);

134  if (s == NULL) return NULL;

135  break;

136 

137  // minute [0, 59]

138  case 'M':

139  s = _parse_num(s, 0, 59, &tm->tm_min);

140  if (s == NULL) return NULL;

141  break;

142 

143  // seconds [0, 60]. 60 is for leap year.

144  case 'S':

145  s = _parse_num(s, 0, 60, &tm->tm_sec);

146  if (s == NULL) return NULL;

147  break;

148 

149  // year [1900, 9999].

150  case 'Y':

151  s = _parse_num(s, 1900, 9999, &tm->tm_year);

152  if (s == NULL) return NULL;

153  tm->tm_year -= 1900;

154  break;

155 

156  // year [0, 99].

157  case 'y':

158  s = _parse_num(s, 0, 99, &tm->tm_year);

159  if (s == NULL) return NULL;

160  if (tm->tm_year <= 68) {

161  tm->tm_year += 100;

162  }

163  break;

164 

165  // arbitray whitespace.

166  case 't':

167  case 'n':

168  while (isspace(*s)) ++s;

169  break;

170 

171  // '%'.

172  case '%':

173  if (*s != '%') return NULL;

174  ++s;

175  break;

176 

177  // All the other format are not supported.

178  default:

179  return NULL;

180  }

181  ++format;

182  }

183 

184  if (*format != NULL) {

185  return NULL;

186  } else {

187  return (char*)(s);

188  }

189 }

190 

191 char* strptime(const char *buf, const char *fmt, struct tm *tm) {

192  return _strptime(buf, fmt, tm);

193 }

194 #endif // WIN32

195 

196 

197 

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