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cc65/libsrc/common/strftime.c
2017-06-28 20:43:31 +02:00

225 lines
7.9 KiB
C

/*****************************************************************************/
/* */
/* strftime.c */
/* */
/* Convert broken down time to a string in a user specified format */
/* */
/* */
/* */
/* (C) 2002 Ullrich von Bassewitz */
/* Wacholderweg 14 */
/* D-70597 Stuttgart */
/* EMail: uz@musoftware.de */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
#include <string.h>
#include <stdio.h>
#include <time.h>
/* Use static local variables for speed */
#pragma static-locals (on);
/*****************************************************************************/
/* Code */
/*****************************************************************************/
size_t __fastcall__ strftime (char* buf, size_t bufsize, const char* format,
const struct tm* tm)
{
static const char* const days[7] = {
"Sunday", "Monday", "Tuesday", "Wednesday",
"Thursday", "Friday", "Saturday"
};
static const char* const months[12] = {
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
};
unsigned count;
unsigned len;
char c;
char arg[40];
const char* argptr;
/* Copy until we reach the end of the format string or a format specifier */
count = 0;
while (1) {
if (count >= bufsize) {
/* Not enough buffer space available */
return 0;
}
if ((c = *format++) == '\0') {
/* End of format string reached */
*buf = '\0';
return count;
}
if (c == '%') {
/* Format specifier */
argptr = arg;
switch (*format++) {
case '%':
arg[0] = '%';
arg[1] = '\0';
break;
case 'A':
argptr = days[tm->tm_wday];
break;
case 'B':
argptr = months[tm->tm_mon];
break;
case 'D':
sprintf (arg, "%02d/%02d/%02d", tm->tm_mon + 1,
tm->tm_mday, tm->tm_year % 100);
break;
case 'F':
/* C99 */
sprintf (arg, "%04d-%02d-%02d", tm->tm_year + 1900,
tm->tm_mon + 1, tm->tm_mday);
break;
case 'H':
sprintf (arg, "%02d", tm->tm_hour);
break;
case 'I':
sprintf (arg, "%02d", (tm->tm_hour + 11) % 12 + 1);
break;
case 'M':
sprintf (arg, "%02d", tm->tm_min);
break;
case 'P':
/* GNU extension */
argptr = (tm->tm_hour >= 12)? "pm" : "am";
break;
case 'S':
sprintf (arg, "%02d", tm->tm_sec);
break;
case 'U':
sprintf (arg, "%02d", (tm->tm_yday + 7 - tm->tm_wday) / 7);
break;
case 'W':
sprintf (arg, "%02d",
(tm->tm_yday + 7 - (tm->tm_wday? tm->tm_wday - 1 : 6)) / 7);
break;
case 'X':
sprintf (arg, "%02d:%02d:%02d", tm->tm_hour,
tm->tm_min, tm->tm_sec);
break;
case 'Y':
sprintf (arg, "%4d", tm->tm_year + 1900);
break;
case 'Z':
argptr = tm->tm_isdst? _tz.dstname : _tz.tzname;
break;
case 'a':
sprintf (arg, "%.3s", days[tm->tm_wday]);
break;
case 'b':
sprintf (arg, "%.3s", months[tm->tm_mon]);
break;
case 'c':
sprintf (arg, "%.3s %.3s%3d %02d:%02d:%02d %d",
days[tm->tm_wday], months[tm->tm_mon],
tm->tm_mday, tm->tm_hour, tm->tm_min,
tm->tm_sec, tm->tm_year + 1900);
break;
case 'd':
sprintf (arg, "%02d", tm->tm_mday);
break;
case 'j':
sprintf (arg, "%03d", tm->tm_yday + 1);
break;
case 'm':
sprintf (arg, "%02d", tm->tm_mon + 1);
break;
case 'p':
argptr = (tm->tm_hour >= 12)? "PM" : "AM";
break;
case 'w':
sprintf (arg, "%d", tm->tm_wday);
break;
case 'x':
sprintf (arg, "%04d-%02d-%02d", tm->tm_year + 1900,
tm->tm_mon + 1, tm->tm_mday);
break;
case 'y':
sprintf (arg, "%02d", tm->tm_year % 100);
break;
default:
/* Unknown format specifier, convert to empty string */
arg[0] = '\0';
break;
}
/* Check if we have enough space to copy the argument string */
len = strlen (argptr);
count += len;
if (count < bufsize) {
memcpy (buf, argptr, len);
buf += len;
}
} else {
/* No format character, just copy */
*buf++ = c;
++count;
}
}
}