Commit 3bea47883a
Changed files (1)
lib
std
lib/std/time.zig
@@ -135,7 +135,7 @@ pub const Instant = struct {
const clock_id = switch (builtin.os.tag) {
.windows => {
// QPC on windows doesn't fail on >= XP/2000 and includes time suspended.
- return Instant{ .timestamp = windows.QueryPerformanceCounter() };
+ return .{ .timestamp = windows.QueryPerformanceCounter() };
},
.wasi => {
var ns: std.os.wasi.timestamp_t = undefined;
@@ -147,7 +147,7 @@ pub const Instant = struct {
var value: std.os.uefi.Time = undefined;
const status = std.os.uefi.system_table.runtime_services.getTime(&value, null);
if (status != .success) return error.Unsupported;
- return Instant{ .timestamp = value.toEpoch() };
+ return .{ .timestamp = value.toEpoch() };
},
// On darwin, use UPTIME_RAW instead of MONOTONIC as it ticks while
// suspended.
@@ -185,36 +185,38 @@ pub const Instant = struct {
/// This assumes that the `earlier` Instant represents a moment in time before or equal to `self`.
/// This also assumes that the time that has passed between both Instants fits inside a u64 (~585 yrs).
pub fn since(self: Instant, earlier: Instant) u64 {
- if (builtin.os.tag == .windows) {
- // We don't need to cache QPF as it's internally just a memory read to KUSER_SHARED_DATA
- // (a read-only page of info updated and mapped by the kernel to all processes):
- // https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/ntddk/ns-ntddk-kuser_shared_data
- // https://www.geoffchappell.com/studies/windows/km/ntoskrnl/inc/api/ntexapi_x/kuser_shared_data/index.htm
- const qpc = self.timestamp - earlier.timestamp;
- const qpf = windows.QueryPerformanceFrequency();
-
- // 10Mhz (1 qpc tick every 100ns) is a common enough QPF value that we can optimize on it.
- // https://github.com/microsoft/STL/blob/785143a0c73f030238ef618890fd4d6ae2b3a3a0/stl/inc/chrono#L694-L701
- const common_qpf = 10_000_000;
- if (qpf == common_qpf) {
- return qpc * (ns_per_s / common_qpf);
- }
-
- // Convert to ns using fixed point.
- const scale = @as(u64, std.time.ns_per_s << 32) / @as(u32, @intCast(qpf));
- const result = (@as(u96, qpc) * scale) >> 32;
- return @as(u64, @truncate(result));
- }
-
- // WASI timestamps are directly in nanoseconds
- if (builtin.os.tag == .wasi) {
- return self.timestamp - earlier.timestamp;
+ switch (builtin.os.tag) {
+ .windows => {
+ // We don't need to cache QPF as it's internally just a memory read to KUSER_SHARED_DATA
+ // (a read-only page of info updated and mapped by the kernel to all processes):
+ // https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/ntddk/ns-ntddk-kuser_shared_data
+ // https://www.geoffchappell.com/studies/windows/km/ntoskrnl/inc/api/ntexapi_x/kuser_shared_data/index.htm
+ const qpc = self.timestamp - earlier.timestamp;
+ const qpf = windows.QueryPerformanceFrequency();
+
+ // 10Mhz (1 qpc tick every 100ns) is a common enough QPF value that we can optimize on it.
+ // https://github.com/microsoft/STL/blob/785143a0c73f030238ef618890fd4d6ae2b3a3a0/stl/inc/chrono#L694-L701
+ const common_qpf = 10_000_000;
+ if (qpf == common_qpf) {
+ return qpc * (ns_per_s / common_qpf);
+ }
+
+ // Convert to ns using fixed point.
+ const scale = @as(u64, std.time.ns_per_s << 32) / @as(u32, @intCast(qpf));
+ const result = (@as(u96, qpc) * scale) >> 32;
+ return @as(u64, @truncate(result));
+ },
+ .uefi, .wasi => {
+ // UEFI and WASI timestamps are directly in nanoseconds
+ return self.timestamp - earlier.timestamp;
+ },
+ else => {
+ // Convert timespec diff to ns
+ const seconds = @as(u64, @intCast(self.timestamp.sec - earlier.timestamp.sec));
+ const elapsed = (seconds * ns_per_s) + @as(u32, @intCast(self.timestamp.nsec));
+ return elapsed - @as(u32, @intCast(earlier.timestamp.nsec));
+ },
}
-
- // Convert timespec diff to ns
- const seconds = @as(u64, @intCast(self.timestamp.sec - earlier.timestamp.sec));
- const elapsed = (seconds * ns_per_s) + @as(u32, @intCast(self.timestamp.nsec));
- return elapsed - @as(u32, @intCast(earlier.timestamp.nsec));
}
};