Files
@ r15899:3bbe04d427d2
Branch filter:
Location: cpp/openttd-patchpack/source/src/date_type.h
r15899:3bbe04d427d2
4.0 KiB
text/x-c
(svn r20593) -Fix: (rlongago, r20547): long ago the service interval was int16, after which is got converted to Date except in the order backup. Much later I copied the savegame snippets from a vehicle and applied that on the order backup. Presto, reading/writing 32 bits (of Date) into 16 bits of ancient style service interval. That would then "spoil" the name pointer and that eventually crashes OpenTTD as it's likely to be an invalid pointer.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 | /* $Id$ */
/*
* This file is part of OpenTTD.
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file date_type.h Types related to the dates in OpenTTD. */
#ifndef DATE_TYPE_H
#define DATE_TYPE_H
typedef int32 Date; ///< The type to store our dates in
typedef uint16 DateFract; ///< The fraction of a date we're in, i.e. the number of ticks since the last date changeover
typedef int32 Ticks; ///< The type to store ticks in
typedef int32 Year; ///< Type for the year, note: 0 based, i.e. starts at the year 0.
typedef uint8 Month; ///< Type for the month, note: 0 based, i.e. 0 = January, 11 = December.
typedef uint8 Day; ///< Type for the day of the month, note: 1 based, first day of a month is 1.
/**
* 1 day is 74 ticks; _date_fract used to be uint16 and incremented by 885. On
* an overflow the new day begun and 65535 / 885 = 74.
* 1 tick is approximately 30 ms.
* 1 day is thus about 2 seconds (74 * 30 = 2220) on a machine that can run OpenTTD normally
*/
static const int DAY_TICKS = 74; ///< ticks per day
static const int DAYS_IN_YEAR = 365; ///< days per year
static const int DAYS_IN_LEAP_YEAR = 366; ///< sometimes, you need one day more...
/*
* ORIGINAL_BASE_YEAR, ORIGINAL_MAX_YEAR and DAYS_TILL_ORIGINAL_BASE_YEAR are
* primarily used for loading newgrf and savegame data and returning some
* newgrf (callback) functions that were in the original (TTD) inherited
* format, where '_date == 0' meant that it was 1920-01-01.
*/
/** The minimum starting year/base year of the original TTD */
static const Year ORIGINAL_BASE_YEAR = 1920;
/** The original ending year */
static const Year ORIGINAL_END_YEAR = 2051;
/** The maximum year of the original TTD */
static const Year ORIGINAL_MAX_YEAR = 2090;
/**
* Calculate the number of leap years till a given year.
*
* Each passed leap year adds one day to the 'day count'.
*
* A special case for the year 0 as no year has been passed,
* but '(year - 1) / 4' does not yield '-1' to counteract the
* '+1' at the end of the formula as divisions round to zero.
*
* @param year the year to get the leap years till.
* @return the number of leap years.
*/
#define LEAP_YEARS_TILL(year) ((year) == 0 ? 0 : ((year) - 1) / 4 - ((year) - 1) / 100 + ((year) - 1) / 400 + 1)
/**
* Calculate the date of the first day of a given year.
* @param year the year to get the first day of.
* @return the date.
*/
#define DAYS_TILL(year) (DAYS_IN_YEAR * (year) + LEAP_YEARS_TILL(year))
/**
* The offset in days from the '_date == 0' till
* 'ConvertYMDToDate(ORIGINAL_BASE_YEAR, 0, 1)'
*/
#define DAYS_TILL_ORIGINAL_BASE_YEAR DAYS_TILL(ORIGINAL_BASE_YEAR)
/** The absolute minimum & maximum years in OTTD */
static const Year MIN_YEAR = 0;
/** The default starting year */
static const Year DEF_START_YEAR = 1950;
/**
* MAX_YEAR, nicely rounded value of the number of years that can
* be encoded in a single 32 bits date, about 2^31 / 366 years.
*/
static const Year MAX_YEAR = 5000000;
/** The number of days till the last day */
#define MAX_DAY (DAYS_TILL(MAX_YEAR + 1) - 1)
/**
* Data structure to convert between Date and triplet (year, month, and day).
* @see ConvertDateToYMD(), ConvertYMDToDate()
*/
struct YearMonthDay {
Year year; ///< Year (0...)
Month month; ///< Month (0..11)
Day day; ///< Day (1..31)
};
static const Year INVALID_YEAR = -1; ///< Representation of an invalid year
static const Date INVALID_DATE = -1; ///< Representation of an invalid date
static const Ticks INVALID_TICKS = -1; ///< Representation of an invalid number of ticks
#endif /* DATE_TYPE_H */
|