+ size_t rc = 0;
+
+ while ( rc < maxsize )
+ {
+ if ( *format != '%' )
+ {
+ if ( ( s[rc] = *format++ ) == '\0' )
+ {
+ return rc;
+ }
+ else
+ {
+ ++rc;
+ }
+ }
+ else
+ {
+ /* char flag = 0; */
+ switch ( *++format )
+ {
+ case 'E':
+ case 'O':
+ /* flag = *format++; */
+ break;
+ default:
+ /* EMPTY */
+ break;
+ }
+ switch( *format++ )
+ {
+ case 'a':
+ {
+ /* tm_wday abbreviated */
+ const char * day = _PDCLIB_lconv.day_name_abbr[ timeptr->tm_wday ];
+ size_t len = strlen( day );
+ if ( rc < ( maxsize - len ) )
+ {
+ strcpy( s + rc, day );
+ rc += len;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'A':
+ {
+ /* tm_wday full */
+ const char * day = _PDCLIB_lconv.day_name_full[ timeptr->tm_wday ];
+ size_t len = strlen( day );
+ if ( rc < ( maxsize - len ) )
+ {
+ strcpy( s + rc, day );
+ rc += len;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'b':
+ case 'h':
+ {
+ /* tm_mon abbreviated */
+ const char * month = _PDCLIB_lconv.month_name_abbr[ timeptr->tm_mon ];
+ size_t len = strlen( month );
+ if ( rc < ( maxsize - len ) )
+ {
+ strcpy( s + rc, month );
+ rc += len;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'B':
+ {
+ /* tm_mon full */
+ const char * month = _PDCLIB_lconv.month_name_full[ timeptr->tm_mon ];
+ size_t len = strlen( month );
+ if ( rc < ( maxsize - len ) )
+ {
+ strcpy( s + rc, month );
+ rc += len;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'c':
+ {
+ /* locale's date / time representation, %a %b %e %T %Y for C locale */
+ /* 'E' for locale's alternative representation */
+ size_t count = strftime( s + rc, maxsize - rc, _PDCLIB_lconv.date_time_format, timeptr );
+ if ( count == 0 )
+ {
+ return 0;
+ }
+ else
+ {
+ rc += count;
+ }
+ break;
+ }
+ case 'C':
+ {
+ /* tm_year divided by 100, truncated to decimal (00-99) */
+ /* 'E' for base year (period) in locale's alternative representation */
+ if ( rc < ( maxsize - 2 ) )
+ {
+ div_t period = div( ( ( timeptr->tm_year + 1900 ) / 100 ), 10 );
+ s[rc++] = '0' + period.quot;
+ s[rc++] = '0' + period.rem;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'd':
+ {
+ /* tm_mday as decimal (01-31) */
+ /* 'O' for locale's alternative numeric symbols */
+ if ( rc < ( maxsize - 2 ) )
+ {
+ div_t day = div( timeptr->tm_mday, 10 );
+ s[rc++] = '0' + day.quot;
+ s[rc++] = '0' + day.rem;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'D':
+ {
+ /* %m/%d/%y */
+ size_t count = strftime( s + rc, maxsize - rc, "%m/%d/%y", timeptr );
+ if ( count == 0 )
+ {
+ return 0;
+ }
+ else
+ {
+ rc += count;
+ }
+ break;
+ }
+ case 'e':
+ {
+ /* tm_mday as decimal ( 1-31) */
+ /* 'O' for locale's alternative numeric symbols */
+ if ( rc < ( maxsize - 2 ) )
+ {
+ div_t day = div( timeptr->tm_mday, 10 );
+ s[rc++] = ( day.quot > 0 ) ? '0' + day.quot : ' ';
+ s[rc++] = '0' + day.rem;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'F':
+ {
+ /* %Y-%m-%d */
+ size_t count = strftime( s + rc, maxsize - rc, "%Y-%m-%d", timeptr );
+ if ( count == 0 )
+ {
+ return 0;
+ }
+ else
+ {
+ rc += count;
+ }
+ break;
+ }
+ case 'g':
+ {
+ /* last 2 digits of the week-based year as decimal (00-99) */
+ /* TODO: 'g' */
+ break;
+ }
+ case 'G':
+ {
+ /* week-based year as decimal (e.g. 1997) */
+ /* TODO: 'G' */
+ break;
+ }
+ case 'H':
+ {
+ /* tm_hour as 24h decimal (00-23) */
+ /* 'O' for locale's alternative numeric symbols */
+ if ( rc < ( maxsize - 2 ) )
+ {
+ div_t hour = div( timeptr->tm_hour, 10 );
+ s[rc++] = '0' + hour.quot;
+ s[rc++] = '0' + hour.rem;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'I':
+ {
+ /* tm_hour as 12h decimal (01-12) */
+ /* 'O' for locale's alternative numeric symbols */
+ if ( rc < ( maxsize - 2 ) )
+ {
+ div_t hour = div( ( timeptr->tm_hour + 1 ) % 12, 10 );
+ s[rc++] = '0' + hour.quot;
+ s[rc++] = '0' + hour.rem;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'j':
+ {
+ /* tm_yday as decimal (001-366) */
+ if ( rc < ( maxsize - 3 ) )
+ {
+ div_t yday = div( timeptr->tm_yday, 100 );
+ s[rc++] = '0' + yday.quot;
+ s[rc++] = '0' + yday.rem / 10;
+ s[rc++] = '0' + yday.rem % 10;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'm':
+ {
+ /* tm_mon as decimal (01-12) */
+ /* 'O' for locale's alternative numeric symbols */
+ if ( rc < ( maxsize - 2 ) )
+ {
+ div_t mon = div( timeptr->tm_mon + 1, 10 );
+ s[rc++] = '0' + mon.quot;
+ s[rc++] = '0' + mon.rem;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'M':
+ {
+ /* tm_min as decimal (00-59) */
+ /* 'O' for locale's alternative numeric symbols */
+ if ( rc < ( maxsize - 2 ) )
+ {
+ div_t min = div( timeptr->tm_min, 10 );
+ s[rc++] = '0' + min.quot;
+ s[rc++] = '0' + min.rem;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'n':
+ {
+ /* newline */
+ s[rc++] = '\n';
+ break;
+ }
+ case 'p':
+ {
+ /* tm_hour locale's AM/PM designations */
+ const char * designation = _PDCLIB_lconv.am_pm[ timeptr->tm_hour > 11 ];
+ size_t len = strlen( designation );
+ if ( rc < ( maxsize - len ) )
+ {
+ strcpy( s + rc, designation );
+ rc += len;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'r':
+ {
+ /* tm_hour / tm_min / tm_sec as locale's 12-hour clock time, %I:%M:%S %p for C locale */
+ size_t count = strftime( s + rc, maxsize - rc, _PDCLIB_lconv.time_format_12h, timeptr );
+ if ( count == 0 )
+ {
+ return 0;
+ }
+ else
+ {
+ rc += count;
+ }
+ break;
+ }
+ case 'R':
+ {
+ /* %H:%M */
+ size_t count = strftime( s + rc, maxsize - rc, "%H:%M", timeptr );
+ if ( count == 0 )
+ {
+ return 0;
+ }
+ else
+ {
+ rc += count;
+ }
+ break;
+ }
+ case 'S':
+ {
+ /* tm_sec as decimal (00-60) */
+ /* 'O' for locale's alternative numeric symbols */
+ if ( rc < ( maxsize - 2 ) )
+ {
+ div_t sec = div( timeptr->tm_sec, 10 );
+ s[rc++] = '0' + sec.quot;
+ s[rc++] = '0' + sec.rem;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 't':
+ {
+ /* tabulator */
+ s[rc++] = '\t';
+ break;
+ }
+ case 'T':
+ {
+ /* %H:%M:%S */
+ size_t count = strftime( s + rc, maxsize - rc, "%H:%M:%S", timeptr );
+ if ( count == 0 )
+ {
+ return 0;
+ }
+ else
+ {
+ rc += count;
+ }
+ break;
+ }
+ case 'u':
+ {
+ /* tm_wday as decimal (1-7) with Monday == 1 */
+ /* 'O' for locale's alternative numeric symbols */
+ s[rc++] = ( timeptr->tm_wday == 0 ) ? '7' : '0' + timeptr->tm_wday;
+ break;
+ }
+ case 'U':
+ {
+ /* week number of the year (first Sunday as the first day of week 1) as decimal (00-53) */
+ /* 'O' for locale's alternative numeric symbols */
+ /* TODO: 'U' */
+ break;
+ }
+ case 'V':
+ {
+ /* week number as decimal (01-53) */
+ /* 'O' for locale's alternative numeric symbols */
+ /* TODO: 'V' */
+ break;
+ }
+ case 'w':
+ {
+ /* tm_wday as decimal number (0-6) with Sunday == 0 */
+ /* 'O' for locale's alternative numeric symbols */
+ s[rc++] = '0' + timeptr->tm_wday;
+ break;
+ }
+ case 'W':
+ {
+ /* week number of the year (first Monday as the first day of week 1) as decimal (00-53) */
+ /* 'O' for locale's alternative numeric symbols */
+ /* TODO: 'W' */
+ break;
+ }
+ case 'x':
+ {
+ /* locale's date representation, %m/%d/%y for C locale */
+ /* 'E' for locale's alternative representation */
+ size_t count = strftime( s + rc, maxsize - rc, _PDCLIB_lconv.date_format, timeptr );
+ if ( count == 0 )
+ {
+ return 0;
+ }
+ else
+ {
+ rc += count;
+ }
+ break;
+ }
+ case 'X':
+ {
+ /* locale's time representation, %T for C locale */
+ /* 'E' for locale's alternative representation */
+ size_t count = strftime( s + rc, maxsize - rc, _PDCLIB_lconv.time_format, timeptr );
+ if ( count == 0 )
+ {
+ return 0;
+ }
+ else
+ {
+ rc += count;
+ }
+ break;
+ }
+ case 'y':
+ {
+ /* last 2 digits of tm_year as decimal (00-99) */
+ /* 'E' for offset from %EC (year only) in locale's alternative representation */
+ /* 'O' for locale's alternative numeric symbols */
+ if ( rc < ( maxsize - 2 ) )
+ {
+ div_t year = div( ( timeptr->tm_year % 100 ), 10 );
+ s[rc++] = '0' + year.quot;
+ s[rc++] = '0' + year.rem;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'Y':
+ {
+ /* tm_year as decimal (e.g. 1997) */
+ /* 'E' for locale's alternative representation */
+ if ( rc < ( maxsize - 4 ) )
+ {
+ int year = timeptr->tm_year + 1900;
+
+ for ( int i = 3; i >= 0; --i )
+ {
+ div_t digit = div( year, 10 );
+ s[ rc + i ] = '0' + digit.rem;
+ year = digit.quot;
+ }
+
+ rc += 4;
+ }
+ else
+ {
+ return 0;
+ }
+ break;
+ }
+ case 'z':
+ {
+ /* tm_isdst / UTC offset in ISO8601 format (e.g. -0430 meaning 4 hours 30 minutes behind Greenwich), or no characters */
+ /* TODO: 'z' */
+ break;
+ }
+ case 'Z':
+ {
+ /* tm_isdst / locale's time zone name or abbreviation, or no characters */
+ /* TODO: 'Z' */
+ break;
+ }
+ case '%':
+ {
+ /* '%' character */
+ s[rc++] = '%';
+ break;
+ }
+ }
+ }
+ }
+