Atlas - SDL_systime.c

Atlas - SDL_systime.c
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1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2025 Sam Lantinga <[email protected]>
4
5  This software is provided 'as-is', without any express or implied
6  warranty.  In no event will the authors be held liable for any damages
7  arising from the use of this software.
8
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12
13  1. The origin of this software must not be misrepresented; you must not
14     claim that you wrote the original software. If you use this software
15     in a product, an acknowledgment in the product documentation would be
16     appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18     misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20*/
21#include "SDL_internal.h"
22
23#ifdef SDL_TIME_N3DS
24
25#include "../SDL_time_c.h"
26#include <3ds.h>
27
28/*
29 * The 3DS clock is essentially a simple digital watch and provides
30 * no timezone or DST functionality.
31 */
32
33// 3DS epoch is Jan 1 1900
34#define DELTA_EPOCH_1900_OFFSET_MS 2208988800000LL
35
36/* Returns year/month/day triple in civil calendar
37 * Preconditions:  z is number of days since 1970-01-01 and is in the range:
38 *                 [INT_MIN, INT_MAX-719468].
39 *
40 * http://howardhinnant.github.io/date_algorithms.html#civil_from_days
41 */
42static void civil_from_days(int days, int *year, int *month, int *day)
43{
44    days += 719468;
45    const int era = (days >= 0 ? days : days - 146096) / 146097;
46    const unsigned doe = (unsigned)(days - era * 146097);                       // [0, 146096]
47    const unsigned yoe = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365; // [0, 399]
48    const int y = (int)(yoe) + era * 400;
49    const unsigned doy = doe - (365 * yoe + yoe / 4 - yoe / 100); // [0, 365]
50    const unsigned mp = (5 * doy + 2) / 153;                      // [0, 11]
51    const unsigned d = doy - (153 * mp + 2) / 5 + 1;              // [1, 31]
52    const unsigned m = mp < 10 ? mp + 3 : mp - 9;                 // [1, 12]
53
54    *year = y + (m <= 2);
55    *month = (int)m;
56    *day = (int)d;
57}
58
59void SDL_GetSystemTimeLocalePreferences(SDL_DateFormat *df, SDL_TimeFormat *tf)
60{
61    // The 3DS only has 12 supported languages, so take the standard for each
62    static const SDL_DateFormat LANG_TO_DATE_FORMAT[] = {
63        SDL_DATE_FORMAT_YYYYMMDD, // JP
64        SDL_DATE_FORMAT_DDMMYYYY, // EN, assume non-american format
65        SDL_DATE_FORMAT_DDMMYYYY, // FR
66        SDL_DATE_FORMAT_DDMMYYYY, // DE
67        SDL_DATE_FORMAT_DDMMYYYY, // IT
68        SDL_DATE_FORMAT_DDMMYYYY, // ES
69        SDL_DATE_FORMAT_YYYYMMDD, // ZH (CN)
70        SDL_DATE_FORMAT_YYYYMMDD, // KR
71        SDL_DATE_FORMAT_DDMMYYYY, // NL
72        SDL_DATE_FORMAT_DDMMYYYY, // PT
73        SDL_DATE_FORMAT_DDMMYYYY, // RU
74        SDL_DATE_FORMAT_YYYYMMDD  // ZH (TW)
75    };
76    u8 system_language, is_north_america;
77    Result result, has_region;
78
79    if (R_FAILED(cfguInit())) {
80        return;
81    }
82    result = CFGU_GetSystemLanguage(&system_language);
83    has_region = CFGU_GetRegionCanadaUSA(&is_north_america);
84    cfguExit();
85    if (R_FAILED(result)) {
86        return;
87    }
88
89    if (df) {
90        *df = LANG_TO_DATE_FORMAT[system_language];
91    }
92    if (tf) {
93        *tf = SDL_TIME_FORMAT_24HR;
94    }
95
96    /* Only American English (en_US) uses MM/DD/YYYY and 12hr system, this gets
97       the formats wrong for canadians though (en_CA) */
98    if (system_language == CFG_LANGUAGE_EN &&
99        R_SUCCEEDED(has_region) && is_north_america) {
100        if (df) {
101            *df = SDL_DATE_FORMAT_MMDDYYYY;
102        }
103        if (tf) {
104            *tf = SDL_TIME_FORMAT_12HR;
105        }
106    }
107}
108
109bool SDL_GetCurrentTime(SDL_Time *ticks)
110{
111    CHECK_PARAM(!ticks) {
112        return SDL_InvalidParamError("ticks");
113    }
114
115    // Returns milliseconds since the epoch.
116    const Uint64 ndsTicksMax = (SDL_MAX_TIME / SDL_NS_PER_MS) + DELTA_EPOCH_1900_OFFSET_MS;
117    const Uint64 ndsTicks = SDL_min(osGetTime(), ndsTicksMax);
118
119    *ticks = SDL_MS_TO_NS(ndsTicks - DELTA_EPOCH_1900_OFFSET_MS);
120
121    return true;
122}
123
124bool SDL_TimeToDateTime(SDL_Time ticks, SDL_DateTime *dt, bool localTime)
125{
126    CHECK_PARAM(!dt) {
127        return SDL_InvalidParamError("dt");
128    }
129
130    const int days = (int)(SDL_NS_TO_SECONDS(ticks) / SDL_SECONDS_PER_DAY);
131    civil_from_days(days, &dt->year, &dt->month, &dt->day);
132
133    int rem = (int)(SDL_NS_TO_SECONDS(ticks) - (days * SDL_SECONDS_PER_DAY));
134    dt->hour = rem / (60 * 60);
135    rem -= dt->hour * 60 * 60;
136    dt->minute = rem / 60;
137    rem -= dt->minute * 60;
138    dt->second = rem;
139    dt->nanosecond = ticks % SDL_NS_PER_SECOND;
140    dt->utc_offset = 0; // Unknown
141
142    SDL_CivilToDays(dt->year, dt->month, dt->day, &dt->day_of_week, NULL);
143
144    return true;
145}
146
147#endif // SDL_TIME_N3DS
148
[FILE END]
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