1 | /* |
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2 | * strftime.c |
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3 | * |
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4 | * Public-domain relatively quick-and-dirty implemenation of |
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5 | * ANSI library routine for System V Unix systems. |
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6 | * |
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7 | * It's written in old-style C for maximal portability. |
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8 | * However, since I'm used to prototypes, I've included them too. |
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9 | * |
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10 | * If you want stuff in the System V ascftime routine, add the SYSV_EXT define. |
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11 | * For stuff needed to implement the P1003.2 date command, add POSIX2_DATE. |
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12 | * For complete POSIX semantics, add POSIX_SEMANTICS. |
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13 | * |
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14 | * The code for %c, %x, and %X is my best guess as to what's "appropriate". |
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15 | * This version ignores LOCALE information. |
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16 | * It also doesn't worry about multi-byte characters. |
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17 | * So there. |
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18 | * |
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19 | * Arnold Robbins |
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20 | * January, February, March, 1991 |
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21 | * Updated March 1992 |
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22 | * |
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23 | * Fixes from ado@elsie.nci.nih.gov |
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24 | * February 1991 |
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25 | * |
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26 | * Fixed compiler warnings from GCC |
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27 | * Olly Betts 2005-01-12 |
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28 | * |
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29 | * Fix memory leak if realloc() fails |
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30 | * Olly Betts 2010-12-21 |
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31 | * |
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32 | * Fix compilation error with GCC |
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33 | * Olly Betts 2010-12-21 |
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34 | */ |
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35 | |
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36 | #include <stdio.h> |
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37 | #include <ctype.h> |
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38 | #include <string.h> |
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39 | #include <time.h> |
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40 | #include <sys/types.h> |
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41 | |
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42 | #ifndef __STDC__ |
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43 | #define const /**/ |
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44 | |
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45 | extern void *malloc(); |
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46 | extern void *realloc(); |
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47 | extern void free(); |
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48 | extern void tzset(); |
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49 | extern char *strchr(); |
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50 | extern char *getenv(); |
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51 | static int weeknumber(); |
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52 | #else |
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53 | #include <stdlib.h> |
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54 | extern void tzset(void); |
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55 | static int weeknumber(const struct tm *timeptr, int firstweekday); |
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56 | #endif |
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57 | |
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58 | #ifdef __GNUC__ |
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59 | #define inline __inline__ |
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60 | #else |
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61 | #define inline /**/ |
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62 | #endif |
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63 | |
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64 | #define range(low, item, hi) max(low, min(item, hi)) |
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65 | |
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66 | extern char *tzname[2]; |
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67 | extern int daylight; |
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68 | |
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69 | #define SYSV_EXT 1 /* stuff in System V ascftime routine */ |
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70 | #define POSIX2_DATE 1 /* stuff in Posix 1003.2 date command */ |
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71 | #define VMS_EXT 1 /* include %V for VMS date format */ |
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72 | #define POSIX_SEMANTICS 1 /* call tzset() if TZ changes */ |
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73 | |
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74 | #if defined(POSIX2_DATE) && ! defined(SYSV_EXT) |
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75 | #define SYSV_EXT 1 |
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76 | #endif |
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77 | |
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78 | /* min --- return minimum of two numbers */ |
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79 | |
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80 | #ifndef __STDC__ |
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81 | static inline int |
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82 | min(a, b) |
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83 | int a, b; |
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84 | #else |
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85 | static inline int |
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86 | min(int a, int b) |
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87 | #endif |
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88 | { |
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89 | return (a < b ? a : b); |
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90 | } |
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91 | |
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92 | /* max --- return maximum of two numbers */ |
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93 | |
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94 | #ifndef __STDC__ |
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95 | static inline int |
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96 | max(a, b) |
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97 | int a, b; |
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98 | #else |
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99 | static inline int |
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100 | max(int a, int b) |
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101 | #endif |
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102 | { |
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103 | return (a > b ? a : b); |
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104 | } |
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105 | |
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106 | /* strftime --- produce formatted time */ |
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107 | |
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108 | #ifndef __STDC__ |
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109 | size_t |
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110 | strftime(s, maxsize, format, timeptr) |
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111 | char *s; |
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112 | size_t maxsize; |
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113 | const char *format; |
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114 | const struct tm *timeptr; |
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115 | #else |
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116 | size_t |
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117 | strftime(char *s, size_t maxsize, const char *format, const struct tm *timeptr) |
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118 | #endif |
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119 | { |
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120 | char *endp = s + maxsize; |
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121 | char *start = s; |
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122 | char tbuf[100]; |
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123 | int i; |
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124 | static short first = 1; |
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125 | static char *savetz = NULL; |
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126 | static int savetzlen = 0; |
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127 | char *tz; |
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128 | int tzlen; |
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129 | |
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130 | /* various tables, useful in North America */ |
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131 | static const char *days_a[] = { |
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132 | "Sun", "Mon", "Tue", "Wed", |
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133 | "Thu", "Fri", "Sat", |
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134 | }; |
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135 | static const char *days_l[] = { |
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136 | "Sunday", "Monday", "Tuesday", "Wednesday", |
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137 | "Thursday", "Friday", "Saturday", |
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138 | }; |
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139 | static const char *months_a[] = { |
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140 | "Jan", "Feb", "Mar", "Apr", "May", "Jun", |
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141 | "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", |
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142 | }; |
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143 | static const char *months_l[] = { |
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144 | "January", "February", "March", "April", |
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145 | "May", "June", "July", "August", "September", |
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146 | "October", "November", "December", |
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147 | }; |
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148 | static const char *ampm[] = { "AM", "PM", }; |
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149 | |
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150 | if (s == NULL || format == NULL || timeptr == NULL || maxsize == 0) |
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151 | return 0; |
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152 | |
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153 | if (strchr(format, '%') == NULL && strlen(format) + 1 >= maxsize) |
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154 | return 0; |
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155 | |
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156 | #ifndef POSIX_SEMANTICS |
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157 | if (first) { |
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158 | tzset(); |
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159 | first = 0; |
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160 | } |
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161 | #else /* POSIX_SEMANTICS */ |
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162 | tz = getenv("TZ"); |
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163 | tzlen = strlen(tz); |
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164 | if (first) { |
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165 | if (tz != NULL) { |
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166 | savetz = (char *) malloc(tzlen + 1); |
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167 | if (savetz != NULL) { |
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168 | savetzlen = tzlen + 1; |
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169 | strcpy(savetz, tz); |
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170 | } |
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171 | } |
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172 | tzset(); |
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173 | first = 0; |
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174 | } |
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175 | /* if we have a saved TZ, and it is different, recapture and reset */ |
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176 | if (tz && savetz && (tz[0] != savetz[0] || strcmp(tz, savetz) != 0)) { |
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177 | i = strlen(tz) + 1; |
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178 | if (i > savetzlen) { |
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179 | char * newsavetz = (char *) realloc(savetz, i); |
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180 | if (newsavetz) { |
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181 | savetzlen = i; |
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182 | strcpy(newsavetz, tz); |
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183 | } else { |
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184 | free(savetz); |
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185 | } |
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186 | savetz = newsavetz; |
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187 | } else |
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188 | strcpy(savetz, tz); |
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189 | tzset(); |
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190 | } |
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191 | #endif /* POSIX_SEMANTICS */ |
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192 | |
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193 | for (; *format && s < endp - 1; format++) { |
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194 | tbuf[0] = '\0'; |
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195 | if (*format != '%') { |
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196 | *s++ = *format; |
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197 | continue; |
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198 | } |
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199 | again: |
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200 | switch (*++format) { |
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201 | case '\0': |
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202 | *s++ = '%'; |
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203 | goto out; |
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204 | |
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205 | case '%': |
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206 | *s++ = '%'; |
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207 | continue; |
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208 | |
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209 | case 'a': /* abbreviated weekday name */ |
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210 | if (timeptr->tm_wday < 0 || timeptr->tm_wday > 6) |
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211 | strcpy(tbuf, "?"); |
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212 | else |
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213 | strcpy(tbuf, days_a[timeptr->tm_wday]); |
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214 | break; |
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215 | |
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216 | case 'A': /* full weekday name */ |
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217 | if (timeptr->tm_wday < 0 || timeptr->tm_wday > 6) |
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218 | strcpy(tbuf, "?"); |
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219 | else |
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220 | strcpy(tbuf, days_l[timeptr->tm_wday]); |
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221 | break; |
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222 | |
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223 | #ifdef SYSV_EXT |
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224 | case 'h': /* abbreviated month name */ |
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225 | #endif |
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226 | case 'b': /* abbreviated month name */ |
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227 | if (timeptr->tm_mon < 0 || timeptr->tm_mon > 11) |
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228 | strcpy(tbuf, "?"); |
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229 | else |
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230 | strcpy(tbuf, months_a[timeptr->tm_mon]); |
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231 | break; |
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232 | |
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233 | case 'B': /* full month name */ |
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234 | if (timeptr->tm_mon < 0 || timeptr->tm_mon > 11) |
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235 | strcpy(tbuf, "?"); |
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236 | else |
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237 | strcpy(tbuf, months_l[timeptr->tm_mon]); |
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238 | break; |
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239 | |
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240 | case 'c': /* appropriate date and time representation */ |
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241 | sprintf(tbuf, "%s %s %2d %02d:%02d:%02d %d", |
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242 | days_a[range(0, timeptr->tm_wday, 6)], |
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243 | months_a[range(0, timeptr->tm_mon, 11)], |
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244 | range(1, timeptr->tm_mday, 31), |
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245 | range(0, timeptr->tm_hour, 23), |
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246 | range(0, timeptr->tm_min, 59), |
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247 | range(0, timeptr->tm_sec, 61), |
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248 | timeptr->tm_year + 1900); |
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249 | break; |
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250 | |
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251 | case 'd': /* day of the month, 01 - 31 */ |
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252 | i = range(1, timeptr->tm_mday, 31); |
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253 | sprintf(tbuf, "%02d", i); |
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254 | break; |
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255 | |
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256 | case 'H': /* hour, 24-hour clock, 00 - 23 */ |
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257 | i = range(0, timeptr->tm_hour, 23); |
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258 | sprintf(tbuf, "%02d", i); |
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259 | break; |
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260 | |
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261 | case 'I': /* hour, 12-hour clock, 01 - 12 */ |
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262 | i = range(0, timeptr->tm_hour, 23); |
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263 | if (i == 0) |
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264 | i = 12; |
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265 | else if (i > 12) |
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266 | i -= 12; |
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267 | sprintf(tbuf, "%02d", i); |
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268 | break; |
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269 | |
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270 | case 'j': /* day of the year, 001 - 366 */ |
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271 | sprintf(tbuf, "%03d", timeptr->tm_yday + 1); |
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272 | break; |
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273 | |
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274 | case 'm': /* month, 01 - 12 */ |
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275 | i = range(0, timeptr->tm_mon, 11); |
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276 | sprintf(tbuf, "%02d", i + 1); |
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277 | break; |
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278 | |
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279 | case 'M': /* minute, 00 - 59 */ |
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280 | i = range(0, timeptr->tm_min, 59); |
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281 | sprintf(tbuf, "%02d", i); |
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282 | break; |
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283 | |
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284 | case 'p': /* am or pm based on 12-hour clock */ |
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285 | i = range(0, timeptr->tm_hour, 23); |
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286 | if (i < 12) |
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287 | strcpy(tbuf, ampm[0]); |
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288 | else |
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289 | strcpy(tbuf, ampm[1]); |
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290 | break; |
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291 | |
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292 | case 'S': /* second, 00 - 61 */ |
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293 | i = range(0, timeptr->tm_sec, 61); |
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294 | sprintf(tbuf, "%02d", i); |
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295 | break; |
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296 | |
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297 | case 'U': /* week of year, Sunday is first day of week */ |
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298 | sprintf(tbuf, "%d", weeknumber(timeptr, 0)); |
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299 | break; |
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300 | |
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301 | case 'w': /* weekday, Sunday == 0, 0 - 6 */ |
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302 | i = range(0, timeptr->tm_wday, 6); |
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303 | sprintf(tbuf, "%d", i); |
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304 | break; |
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305 | |
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306 | case 'W': /* week of year, Monday is first day of week */ |
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307 | sprintf(tbuf, "%d", weeknumber(timeptr, 1)); |
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308 | break; |
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309 | |
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310 | case 'x': /* appropriate date representation */ |
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311 | sprintf(tbuf, "%s %s %2d %d", |
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312 | days_a[range(0, timeptr->tm_wday, 6)], |
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313 | months_a[range(0, timeptr->tm_mon, 11)], |
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314 | range(1, timeptr->tm_mday, 31), |
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315 | timeptr->tm_year + 1900); |
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316 | break; |
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317 | |
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318 | case 'X': /* appropriate time representation */ |
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319 | sprintf(tbuf, "%02d:%02d:%02d", |
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320 | range(0, timeptr->tm_hour, 23), |
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321 | range(0, timeptr->tm_min, 59), |
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322 | range(0, timeptr->tm_sec, 61)); |
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323 | break; |
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324 | |
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325 | case 'y': /* year without a century, 00 - 99 */ |
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326 | i = timeptr->tm_year % 100; |
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327 | sprintf(tbuf, "%d", i); |
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328 | break; |
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329 | |
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330 | case 'Y': /* year with century */ |
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331 | sprintf(tbuf, "%d", 1900 + timeptr->tm_year); |
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332 | break; |
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333 | |
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334 | case 'Z': /* time zone name or abbrevation */ |
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335 | i = 0; |
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336 | if (daylight && timeptr->tm_isdst) |
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337 | i = 1; |
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338 | strcpy(tbuf, tzname[i]); |
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339 | break; |
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340 | |
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341 | #ifdef SYSV_EXT |
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342 | case 'n': /* same as \n */ |
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343 | tbuf[0] = '\n'; |
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344 | tbuf[1] = '\0'; |
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345 | break; |
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346 | |
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347 | case 't': /* same as \t */ |
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348 | tbuf[0] = '\t'; |
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349 | tbuf[1] = '\0'; |
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350 | break; |
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351 | |
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352 | case 'D': /* date as %m/%d/%y */ |
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353 | strftime(tbuf, sizeof tbuf, "%m/%d/%y", timeptr); |
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354 | break; |
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355 | |
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356 | case 'e': /* day of month, blank padded */ |
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357 | sprintf(tbuf, "%2d", range(1, timeptr->tm_mday, 31)); |
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358 | break; |
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359 | |
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360 | case 'r': /* time as %I:%M:%S %p */ |
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361 | strftime(tbuf, sizeof tbuf, "%I:%M:%S %p", timeptr); |
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362 | break; |
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363 | |
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364 | case 'R': /* time as %H:%M */ |
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365 | strftime(tbuf, sizeof tbuf, "%H:%M", timeptr); |
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366 | break; |
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367 | |
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368 | case 'T': /* time as %H:%M:%S */ |
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369 | strftime(tbuf, sizeof tbuf, "%H:%M:%S", timeptr); |
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370 | break; |
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371 | #endif |
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372 | |
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373 | |
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374 | #ifdef VMS_EXT |
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375 | case 'V': /* date as dd-bbb-YYYY */ |
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376 | sprintf(tbuf, "%2d-%3.3s-%4d", |
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377 | range(1, timeptr->tm_mday, 31), |
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378 | months_a[range(0, timeptr->tm_mon, 11)], |
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379 | timeptr->tm_year + 1900); |
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380 | for (i = 3; i < 6; i++) |
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381 | if (islower(tbuf[i])) |
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382 | tbuf[i] = toupper(tbuf[i]); |
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383 | break; |
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384 | #endif |
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385 | |
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386 | |
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387 | #ifdef POSIX2_DATE |
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388 | case 'C': |
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389 | sprintf(tbuf, "%02d", (timeptr->tm_year + 1900) / 100); |
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390 | break; |
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391 | |
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392 | |
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393 | case 'E': |
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394 | case 'O': |
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395 | /* POSIX locale extensions, ignored for now */ |
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396 | goto again; |
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397 | #endif |
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398 | default: |
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399 | tbuf[0] = '%'; |
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400 | tbuf[1] = *format; |
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401 | tbuf[2] = '\0'; |
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402 | break; |
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403 | } |
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404 | i = strlen(tbuf); |
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405 | if (i) { |
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406 | if (s + i < endp - 1) { |
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407 | strcpy(s, tbuf); |
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408 | s += i; |
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409 | } else |
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410 | return 0; |
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411 | } |
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412 | } |
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413 | out: |
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414 | if (s < endp && *format == '\0') { |
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415 | *s = '\0'; |
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416 | return (s - start); |
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417 | } else |
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418 | return 0; |
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419 | } |
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420 | |
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421 | /* weeknumber --- figure how many weeks into the year */ |
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422 | |
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423 | /* With thanks and tip of the hatlo to ado@elsie.nci.nih.gov */ |
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424 | /* Modified byMichal Jaegermann <audfax!emory!vm.ucs.UAlberta.CA!NTOMCZAK> */ |
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425 | |
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426 | #ifndef __STDC__ |
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427 | static int |
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428 | weeknumber(timeptr, firstweekday) |
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429 | const struct tm *timeptr; |
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430 | int firstweekday; |
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431 | #else |
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432 | static int |
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433 | weeknumber(const struct tm *timeptr, int firstweekday) |
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434 | #endif |
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435 | /* |
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436 | * firstweekday is 0 if starting in Sunday, non-zero if in Monday |
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437 | */ |
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438 | { |
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439 | return (timeptr->tm_yday - timeptr->tm_wday + |
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440 | (firstweekday ? (timeptr->tm_wday ? 8 : 1) : 7)) / 7; |
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441 | } |
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