Atlas - SDL_systime.c
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[FILE BEGIN]
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_WINDOWS
24
25#include "../../core/windows/SDL_windows.h"
26
27#include "../SDL_time_c.h"
28
29#define NS_PER_WINDOWS_TICK   100ULL
30#define WINDOWS_TICK          10000000ULL
31#define UNIX_EPOCH_OFFSET_SEC 11644473600ULL
32
33typedef void (WINAPI *pfnGetSystemTimePreciseAsFileTime)(FILETIME *);
34
35void SDL_GetSystemTimeLocalePreferences(SDL_DateFormat *df, SDL_TimeFormat *tf)
36{
37    WCHAR str[80]; // Per the docs, the time and short date format strings can be a max of 80 characters.
38
39    if (df && GetLocaleInfoW(LOCALE_USER_DEFAULT, LOCALE_SSHORTDATE, str, sizeof(str) / sizeof(WCHAR))) {
40        LPWSTR s = str;
41        while (*s) {
42            switch (*s++) {
43            case L'y':
44                *df = SDL_DATE_FORMAT_YYYYMMDD;
45                goto found_date;
46            case L'd':
47                *df = SDL_DATE_FORMAT_DDMMYYYY;
48                goto found_date;
49            case L'M':
50                *df = SDL_DATE_FORMAT_MMDDYYYY;
51                goto found_date;
52            default:
53                break;
54            }
55        }
56    }
57
58found_date:
59
60    // Figure out the preferred system date format.
61    if (tf && GetLocaleInfoW(LOCALE_USER_DEFAULT, LOCALE_STIMEFORMAT, str, sizeof(str) / sizeof(WCHAR))) {
62        LPWSTR s = str;
63        while (*s) {
64            switch (*s++) {
65            case L'H':
66                *tf = SDL_TIME_FORMAT_24HR;
67                return;
68            case L'h':
69                *tf = SDL_TIME_FORMAT_12HR;
70                return;
71            default:
72                break;
73            }
74        }
75    }
76}
77
78bool SDL_GetCurrentTime(SDL_Time *ticks)
79{
80    FILETIME ft;
81
82    CHECK_PARAM(!ticks) {
83        return SDL_InvalidParamError("ticks");
84    }
85
86    SDL_zero(ft);
87
88    static pfnGetSystemTimePreciseAsFileTime pGetSystemTimePreciseAsFileTime = NULL;
89    static bool load_attempted = false;
90
91    // Only available in Win8/Server 2012 or higher.
92    if (!pGetSystemTimePreciseAsFileTime && !load_attempted) {
93        HMODULE kernel32 = GetModuleHandle(TEXT("kernel32.dll"));
94        if (kernel32) {
95            pGetSystemTimePreciseAsFileTime = (pfnGetSystemTimePreciseAsFileTime)GetProcAddress(kernel32, "GetSystemTimePreciseAsFileTime");
96        }
97        load_attempted = true;
98    }
99
100    if (pGetSystemTimePreciseAsFileTime) {
101        pGetSystemTimePreciseAsFileTime(&ft);
102    } else {
103        GetSystemTimeAsFileTime(&ft);
104    }
105
106    *ticks = SDL_TimeFromWindows(ft.dwLowDateTime, ft.dwHighDateTime);
107
108    return true;
109}
110
111bool SDL_TimeToDateTime(SDL_Time ticks, SDL_DateTime *dt, bool localTime)
112{
113    FILETIME ft, local_ft;
114    SYSTEMTIME utc_st, local_st;
115    SYSTEMTIME *st = NULL;
116    Uint32 low, high;
117
118    CHECK_PARAM(!dt) {
119        return SDL_InvalidParamError("dt");
120    }
121
122    SDL_TimeToWindows(ticks, &low, &high);
123    ft.dwLowDateTime = (DWORD)low;
124    ft.dwHighDateTime = (DWORD)high;
125
126    if (FileTimeToSystemTime(&ft, &utc_st)) {
127        if (localTime) {
128            if (SystemTimeToTzSpecificLocalTime(NULL, &utc_st, &local_st)) {
129                // Calculate the difference for the UTC offset.
130                SystemTimeToFileTime(&local_st, &local_ft);
131                const SDL_Time local_ticks = SDL_TimeFromWindows(local_ft.dwLowDateTime, local_ft.dwHighDateTime);
132                dt->utc_offset = (int)SDL_NS_TO_SECONDS(local_ticks - ticks);
133                st = &local_st;
134            }
135        } else {
136            dt->utc_offset = 0;
137            st = &utc_st;
138        }
139
140        if (st) {
141            dt->year = st->wYear;
142            dt->month = st->wMonth;
143            dt->day = st->wDay;
144            dt->hour = st->wHour;
145            dt->minute = st->wMinute;
146            dt->second = st->wSecond;
147            dt->nanosecond = ticks % SDL_NS_PER_SECOND;
148            dt->day_of_week = st->wDayOfWeek;
149
150            return true;
151        }
152    }
153
154    return SDL_SetError("SDL_DateTime conversion failed (%lu)", GetLastError());
155}
156
157#endif // SDL_TIME_WINDOWS
158
[FILE END]
(C) 2025 0x4248
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