git.sur5r.net Git - cc65/blob - libsrc/common/strftime.c

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                strftime.c                                 */
   4 /*                                                                           */
   5 /*      Convert broken down time to a string in a user specified format      */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 2002      Ullrich von Bassewitz                                       */
  10 /*               Wacholderweg 14                                             */
  11 /*               D-70597 Stuttgart                                           */
  12 /* EMail:        uz@musoftware.de                                            */
  13 /*                                                                           */
  14 /*                                                                           */
  15 /* This software is provided 'as-is', without any expressed or implied       */
  16 /* warranty.  In no event will the authors be held liable for any damages    */
  17 /* arising from the use of this software.                                    */
  18 /*                                                                           */
  19 /* Permission is granted to anyone to use this software for any purpose,     */
  20 /* including commercial applications, and to alter it and redistribute it    */
  21 /* freely, subject to the following restrictions:                            */
  22 /*                                                                           */
  23 /* 1. The origin of this software must not be misrepresented; you must not   */
  24 /*    claim that you wrote the original software. If you use this software   */
  25 /*    in a product, an acknowledgment in the product documentation would be  */
  26 /*    appreciated but is not required.                                       */
  27 /* 2. Altered source versions must be plainly marked as such, and must not   */
  28 /*    be misrepresented as being the original software.                      */
  29 /* 3. This notice may not be removed or altered from any source              */
  30 /*    distribution.                                                          */
  31 /*                                                                           */
  32 /*****************************************************************************/
  33
  34
  35
  36 #include <string.h>
  37 #include <stdio.h>
  38 #include <time.h>
  39
  40
  41
  42 /* Use static local variables for speed */
  43 #pragma staticlocals (on);
  44
  45
  46
  47 /*****************************************************************************/
  48 /*                                   Code                                    */
  49 /*****************************************************************************/
  50
  51
  52
  53 size_t __fastcall__ strftime (char* buf, size_t bufsize, const char* format,
  54                               const struct tm* tm)
  55 {
  56     static const char* days[7] = {
  57         "Sunday",   "Monday", "Tuesday", "Wednesday",
  58         "Thursday", "Friday", "Saturday"
  59     };
  60     static const char* months[12] = {
  61         "January", "February", "March", "April", "May", "June",
  62         "July", "August", "September", "October", "November", "December"
  63     };
  64
  65     unsigned    count;
  66     unsigned    len;
  67     char        c;
  68     char        arg[40];
  69     const char* argptr;
  70     unsigned    week;
  71
  72     /* Copy until we reach the end of the format string or a format specifier */
  73     count = 0;
  74     while (1) {
  75         if (count >= bufsize) {
  76             /* Not enough buffer space available */
  77             return 0;
  78         }
  79         if ((c = *format++) == '\0') {
  80             /* End of format string reached */
  81             *buf = '\0';
  82             return count;
  83         }
  84         if (c == '%') {
  85             /* Format specifier */
  86             argptr = arg;
  87             switch (*format++) {
  88
  89                 case '%':
  90                     arg[0] = '%';
  91                     arg[1] = '\0';
  92                     break;
  93
  94                 case 'A':
  95                     argptr = days[tm->tm_wday];
  96                     break;
  97
  98                 case 'B':
  99                     argptr = months[tm->tm_mon];
 100                     break;
 101
 102                 case 'D':
 103                     sprintf (arg, "%02d/%02d/%02d", tm->tm_mon + 1,
 104                              tm->tm_mday, tm->tm_year % 100);
 105                     break;
 106
 107                 case 'F':
 108                     /* C99 */
 109                     sprintf (arg, "%04d-%02d-%02d", tm->tm_year + 1900,
 110                              tm->tm_mon + 1, tm->tm_mday);
 111                     break;
 112
 113                 case 'H':
 114                     sprintf (arg, "%02d", tm->tm_hour);
 115                     break;
 116
 117                 case 'I':
 118                     sprintf (arg, "%02d", tm->tm_hour % 12);
 119                     break;
 120
 121                 case 'M':
 122                     sprintf (arg, "%02d", tm->tm_min);
 123                     break;
 124
 125                 case 'P':
 126                     /* GNU extension */
 127                     argptr = (tm->tm_hour >= 12)? "pm" : "am";
 128                     break;
 129
 130                 case 'S':
 131                     sprintf (arg, "%02d", tm->tm_sec);
 132                     break;
 133
 134                 case 'U':
 135                     week = tm->tm_yday / 7;
 136                     if (tm->tm_mday % 7 > tm->tm_wday) {
 137                         ++week;
 138                     }
 139                     sprintf (arg, "%02u", week);
 140                     break;
 141
 142                 case 'W':
 143                     /* ### This one is buggy */
 144                     week = tm->tm_yday / 7;
 145                     if (tm->tm_mday % 7 > tm->tm_wday) {
 146                         ++week;
 147                     }
 148                     sprintf (arg, "%2u", week);
 149                     break;
 150
 151                 case 'X':
 152                     sprintf (arg, "%02d:%02d:%02d", tm->tm_hour,
 153                              tm->tm_min, tm->tm_sec);
 154                     break;
 155
 156                 case 'Y':
 157                     sprintf (arg, "%4d", tm->tm_year + 1900);
 158                     break;
 159
 160                 case 'Z':
 161                     argptr = tm->tm_isdst? _tz.dstname : _tz.tzname;
 162                     break;
 163
 164                 case 'a':
 165                     sprintf (arg, "%.3s", days[tm->tm_wday]);
 166                     break;
 167
 168                 case 'b':
 169                     sprintf (arg, "%.3s", months[tm->tm_mon]);
 170                     break;
 171
 172                 case 'c':
 173                     sprintf (arg, "%.3s %.3s%3d %02d:%02d:%02d %d",
 174                              days[tm->tm_wday], months[tm->tm_mon],
 175                              tm->tm_mday, tm->tm_hour, tm->tm_min,
 176                              tm->tm_sec, tm->tm_year + 1900);
 177                     break;
 178
 179                 case 'd':
 180                     sprintf (arg, "%02d", tm->tm_mday);
 181                     break;
 182
 183                 case 'j':
 184                     sprintf (arg, "%03d", tm->tm_yday + 1);
 185                     break;
 186
 187                 case 'm':
 188                     sprintf (arg, "%02d", tm->tm_mon + 1);
 189                     break;
 190
 191                 case 'p':
 192                     argptr = (tm->tm_hour >= 12)? "PM" : "AM";
 193                     break;
 194
 195                 case 'w':
 196                     sprintf (arg, "%d", tm->tm_wday);
 197                     break;
 198
 199                 case 'x':
 200                     sprintf (arg, "%04d-%02d-%02d", tm->tm_year + 1900,
 201                              tm->tm_mon + 1, tm->tm_mday);
 202                     break;
 203
 204                 case 'y':
 205                     sprintf (arg, "%02d", tm->tm_year % 100);
 206                     break;
 207
 208                 default:
 209                     /* Unknown format specifier, convert to empty string */
 210                     arg[0] = '\0';
 211                     break;
 212             }
 213
 214             /* Check if we have enough space to copy the argument string */
 215             len = strlen (argptr);
 216             count += len;
 217             if (count < bufsize) {
 218                 memcpy (buf, argptr, len);
 219                 buf += len;
 220             }
 221
 222         } else {
 223
 224             /* No format character, just copy */
 225             *buf++ = c;
 226             ++count;
 227
 228         }
 229     }
 230 }
 231
 232
 233