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ringbuffer.zig
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ringbuffer.zig
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const std = @import("std");
pub fn RingBuffer(comptime size: u32, comptime T: type) type {
return struct {
const Self = @This();
buffer: [size + 1]T = undefined,
writeIdx: u32 = 0,
readIdx: u32 = 0,
pub fn write(self: *Self, elem: T) bool {
const nextWriteIdx = if (self.writeIdx == size) 0 else self.writeIdx + 1;
if (nextWriteIdx == self.readIdx)
return false;
self.buffer[self.writeIdx] = elem;
self.writeIdx = nextWriteIdx;
return true;
}
pub fn read(self: *Self) ?T {
if (self.writeIdx == self.readIdx)
return null;
const result = self.buffer[self.readIdx];
self.readIdx = if (self.readIdx == size) 0 else self.readIdx + 1;
return result;
}
pub fn count(self: Self) u32 {
return if (self.writeIdx >= self.readIdx)
self.writeIdx - self.readIdx
else
(self.writeIdx + size + 1) - self.readIdx;
}
pub fn free(self: Self) u32 {
return size - count(self);
}
pub fn empty(self: Self) bool {
return self.writeIdx == self.readIdx;
}
};
}
test "Ringbuffer" {
const size = 100;
var buffer = RingBuffer(size, u8){};
std.testing.expect(buffer.free() == size);
std.testing.expect(buffer.empty());
var i: u8 = 0;
while (i < size) : (i += 1) {
std.testing.expect(buffer.write(i));
}
std.testing.expect(buffer.write(i) == false);
std.testing.expect(buffer.free() == 0);
std.testing.expect(!buffer.empty());
i = 0;
while (i < size) : (i += 1) {
if (buffer.read()) |v| {
std.testing.expect(v == i);
} else {
std.testing.expect(false);
}
}
std.testing.expect(buffer.empty());
std.testing.expect(buffer.free() == size);
if (buffer.read()) |v| {
std.testing.expect(false);
} else {
std.testing.expect(true);
}
i = 0;
while (i < 10) : (i += 1) {
std.testing.expect(buffer.write(i));
}
std.testing.expect(!buffer.empty());
std.testing.expect(buffer.free() == size - 10);
std.testing.expect(buffer.count() == 10);
while (buffer.read()) |v| {}
std.testing.expect(buffer.empty());
std.testing.expect(buffer.free() == size);
std.testing.expect(buffer.count() == 0);
i = 0;
while (i < size - 10) : (i += 1) {
std.testing.expect(buffer.write(i));
}
std.testing.expect(!buffer.empty());
std.testing.expect(buffer.free() == 10);
std.testing.expect(buffer.count() == size - 10);
}