zba/src/util.zig

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const std = @import("std");
const Log2Int = std.math.Log2Int;
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pub inline fn sext(comptime bits: comptime_int, value: u32) u32 {
comptime std.debug.assert(bits <= 32);
const amount = 32 - bits;
return @bitCast(u32, @bitCast(i32, value << amount) >> amount);
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}
/// See https://godbolt.org/z/W3en9Eche
pub inline fn rotr(comptime T: type, value: T, r: anytype) T {
comptime std.debug.assert(@typeInfo(T).Int.signedness == .unsigned);
const ar = @truncate(Log2Int(T), r);
return value >> ar | value << @truncate(Log2Int(T), @typeInfo(T).Int.bits - @as(T, ar));
}
pub const FpsAverage = struct {
const Self = @This();
total: u64,
sample_count: u64,
pub fn init() Self {
return .{ .total = 0, .sample_count = 0 };
}
pub fn add(self: *Self, sample: u64) void {
if (self.sample_count == 600) return self.reset(sample);
self.total += sample;
self.sample_count += 1;
}
pub fn calc(self: *const Self) u64 {
return self.total / self.sample_count;
}
fn reset(self: *Self, sample: u64) void {
self.total = sample;
self.sample_count = 1;
}
};
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pub fn intToBytes(comptime T: type, value: anytype) [@sizeOf(T)]u8 {
comptime std.debug.assert(@typeInfo(T) == .Int);
var result: [@sizeOf(T)]u8 = undefined;
var i: Log2Int(T) = 0;
while (i < result.len) : (i += 1) result[i] = @truncate(u8, value >> i * @bitSizeOf(u8));
return result;
}