Zachary Levy
440 lines
13 KiB
Odin
440 lines
13 KiB
Odin
package ring
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import "base:runtime"
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import "core:fmt"
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@(private)
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ODIN_BOUNDS_CHECK :: !ODIN_NO_BOUNDS_CHECK
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Ring :: struct($E: typeid) {
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data: []E,
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next_write_index, len: int,
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}
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Ring_Soa :: struct($E: typeid) {
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data: #soa[]E,
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next_write_index, len: int,
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}
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destroy_aos :: #force_inline proc(
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ring: ^Ring($E),
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allocator := context.allocator,
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) -> runtime.Allocator_Error {
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return delete(ring.data)
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}
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destroy_soa :: #force_inline proc(
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ring: ^Ring_Soa($E),
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allocator := context.allocator,
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) -> runtime.Allocator_Error {
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return delete(ring.data)
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}
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destroy :: proc {
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destroy_aos,
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destroy_soa,
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}
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create_aos :: #force_inline proc(
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$E: typeid,
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capacity: int,
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allocator := context.allocator,
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) -> (
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ring: Ring(E),
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err: runtime.Allocator_Error,
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) #optional_allocator_error {
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ring.data, err = make([]E, capacity, allocator)
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return ring, err
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}
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create_soa :: #force_inline proc(
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$E: typeid,
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capacity: int,
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allocator := context.allocator,
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) -> (
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ring: Ring_Soa(E),
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err: runtime.Allocator_Error,
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) #optional_allocator_error {
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ring.data, err = make(#soa[]E, capacity, allocator)
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return ring, err
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}
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// All contents of `data` will be completely ignored, `data` is treated as an empty slice.
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init_from_slice_aos :: #force_inline proc(ring: ^Ring($E), data: $T/[]E) {
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ring.data = data
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ring.len = 0
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ring.next_write_index = 0
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return
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}
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// All contents of `data` will be completely ignored, `data` is treated as an empty slice.
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init_from_slice_soa :: #force_inline proc(ring: ^Ring_Soa($E), data: $T/#soa[]E) {
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ring.data = data
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ring.len = 0
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ring.next_write_index = 0
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return
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}
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init_from_slice :: proc {
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init_from_slice_aos,
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init_from_slice_soa,
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}
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// Internal
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// Index in the backing array where the ring starts
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start_index_aos :: #force_inline proc(ring: Ring($E)) -> int {
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return ring.len < len(ring.data) ? 0 : ring.next_write_index
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}
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// Internal
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// Index in the backing array where the ring starts
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start_index_soa :: #force_inline proc(ring: Ring_Soa($E)) -> int {
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return ring.len < len(ring.data) ? 0 : ring.next_write_index
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}
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advance_aos :: #force_inline proc(ring: ^Ring($E)) {
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// Length
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if ring.len != len(ring.data) do ring.len += 1
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// Write index
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ring.next_write_index += 1
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if ring.next_write_index == len(ring.data) do ring.next_write_index = 0
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}
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advance_soa :: #force_inline proc(ring: ^Ring_Soa($E)) {
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// Length
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if ring.len != len(ring.data) do ring.len += 1
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// Write index
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ring.next_write_index += 1
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if ring.next_write_index == len(ring.data) do ring.next_write_index = 0
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}
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advance :: proc {
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advance_aos,
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advance_soa,
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}
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append_aos :: #force_inline proc(ring: ^Ring($E), element: E) {
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ring.data[ring.next_write_index] = element
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advance(ring)
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}
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append_soa :: #force_inline proc(ring: ^Ring_Soa($E), element: E) {
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ring.data[ring.next_write_index] = element
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advance(ring)
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}
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append :: proc {
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append_aos,
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append_soa,
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}
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get_aos :: #force_inline proc(ring: Ring($E), index: int) -> ^E {
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when ODIN_BOUNDS_CHECK {
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fmt.assertf(index < ring.len, "Ring index %i out of bounds for length %i", index, ring.len)
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}
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array_index := start_index_aos(ring) + index
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if array_index < len(ring.data) {
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return &ring.data[array_index]
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} else {
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array_index = array_index - len(ring.data)
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return &ring.data[array_index]
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}
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}
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// SOA can't return soa pointer to parapoly T.
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get_soa :: #force_inline proc(ring: Ring_Soa($E), index: int) -> E {
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when ODIN_BOUNDS_CHECK {
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fmt.assertf(index < ring.len, "Ring index %i out of bounds for length %i", index, ring.len)
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}
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array_index := start_index_soa(ring) + index
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if array_index < len(ring.data) {
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return ring.data[array_index]
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} else {
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array_index = array_index - len(ring.data)
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return ring.data[array_index]
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}
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}
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get :: proc {
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get_aos,
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get_soa,
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}
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get_last_aos :: #force_inline proc(ring: Ring($E)) -> ^E {
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return get(ring, ring.len - 1)
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}
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get_last_soa :: #force_inline proc(ring: Ring_Soa($E)) -> E {
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return get(ring, ring.len - 1)
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}
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get_last :: proc {
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get_last_aos,
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get_last_soa,
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}
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clear_aos :: #force_inline proc "contextless" (ring: ^Ring($E)) {
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ring.len = 0
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ring.next_write_index = 0
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}
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clear_soa :: #force_inline proc "contextless" (ring: ^Ring_Soa($E)) {
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ring.len = 0
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ring.next_write_index = 0
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}
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clear :: proc {
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clear_aos,
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clear_soa,
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}
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// ---------------------------------------------------------------------------------------------------------------------
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// ----- Tests ------------------------
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// ---------------------------------------------------------------------------------------------------------------------
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import "core:log"
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import "core:testing"
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@(test)
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test_ring_aos :: proc(t: ^testing.T) {
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ring := create_aos(int, 10)
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defer destroy(&ring)
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for i in 1 ..= 5 {
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append(&ring, i)
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log.debug("Length:", ring.len)
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log.debug("Start index:", start_index_aos(ring))
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log.debug("Next write index:", ring.next_write_index)
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log.debug(ring.data)
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}
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testing.expect_value(t, get(ring, 0)^, 1)
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testing.expect_value(t, get(ring, 4)^, 5)
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testing.expect_value(t, ring.len, 5)
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testing.expect_value(t, ring.next_write_index, 5)
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testing.expect_value(t, start_index_aos(ring), 0)
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for i in 6 ..= 15 {
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append(&ring, i)
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log.debug("Length:", ring.len)
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log.debug("Start index:", start_index_aos(ring))
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log.debug("Next write index:", ring.next_write_index)
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log.debug(ring.data)
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}
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testing.expect_value(t, get(ring, 0)^, 6)
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testing.expect_value(t, get(ring, 4)^, 10)
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testing.expect_value(t, get(ring, 9)^, 15)
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testing.expect_value(t, get_last(ring)^, 15)
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testing.expect_value(t, ring.len, 10)
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testing.expect_value(t, ring.next_write_index, 5)
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testing.expect_value(t, start_index_aos(ring), 5)
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for i in 15 ..= 25 {
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append(&ring, i)
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log.debug("Length:", ring.len)
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log.debug("Start index:", start_index_aos(ring))
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log.debug("Next write index:", ring.next_write_index)
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log.debug(ring.data)
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}
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testing.expect_value(t, get(ring, 0)^, 16)
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testing.expect_value(t, ring.next_write_index, 6)
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testing.expect_value(t, get_last(ring)^, 25)
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clear(&ring)
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append(&ring, 1)
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testing.expect_value(t, ring.len, 1)
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testing.expect_value(t, get(ring, 0)^, 1)
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}
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@(test)
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test_ring_soa :: proc(t: ^testing.T) {
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Ints :: struct {
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x, y: int,
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}
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ring := create_soa(Ints, 10)
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defer destroy(&ring)
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for i in 1 ..= 5 {
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append(&ring, Ints{i, i})
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log.debug("Length:", ring.len)
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log.debug("Start index:", start_index_soa(ring))
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log.debug("Next write index:", ring.next_write_index)
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log.debug(ring.data)
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}
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testing.expect_value(t, get(ring, 0), Ints{1, 1})
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testing.expect_value(t, get(ring, 4), Ints{5, 5})
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testing.expect_value(t, ring.len, 5)
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testing.expect_value(t, ring.next_write_index, 5)
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testing.expect_value(t, start_index_soa(ring), 0)
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for i in 6 ..= 15 {
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append(&ring, Ints{i, i})
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log.debug("Length:", ring.len)
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log.debug("Start index:", start_index_soa(ring))
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log.debug("Next write index:", ring.next_write_index)
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log.debug(ring.data)
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}
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testing.expect_value(t, get(ring, 0), Ints{6, 6})
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testing.expect_value(t, get(ring, 4), Ints{10, 10})
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testing.expect_value(t, get(ring, 9), Ints{15, 15})
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testing.expect_value(t, get_last(ring), Ints{15, 15})
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testing.expect_value(t, ring.len, 10)
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testing.expect_value(t, ring.next_write_index, 5)
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testing.expect_value(t, start_index_soa(ring), 5)
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for i in 15 ..= 25 {
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append(&ring, Ints{i, i})
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log.debug("Length:", ring.len)
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log.debug("Start index:", start_index_soa(ring))
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log.debug("Next write index:", ring.next_write_index)
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log.debug(ring.data)
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}
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testing.expect_value(t, get(ring, 0), Ints{16, 16})
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testing.expect_value(t, ring.next_write_index, 6)
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testing.expect_value(t, get_last(ring), Ints{25, 25})
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clear(&ring)
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append(&ring, Ints{1, 1})
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testing.expect_value(t, ring.len, 1)
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testing.expect_value(t, get(ring, 0), Ints{1, 1})
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}
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@(test)
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test_ring_aos_init_from_slice :: proc(t: ^testing.T) {
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// Stack-allocated backing with pre-existing garbage and odd capacity.
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backing: [7]int = {99, 99, 99, 99, 99, 99, 99}
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ring: Ring(int)
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init_from_slice(&ring, backing[:])
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// Empty ring invariants after init_from_slice.
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testing.expect_value(t, ring.len, 0)
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testing.expect_value(t, ring.next_write_index, 0)
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testing.expect_value(t, start_index_aos(ring), 0)
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// Partial fill (3 / 7).
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for i in 1 ..= 3 do append(&ring, i)
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testing.expect_value(t, ring.len, 3)
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testing.expect_value(t, ring.next_write_index, 3)
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testing.expect_value(t, start_index_aos(ring), 0)
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testing.expect_value(t, get(ring, 0)^, 1)
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testing.expect_value(t, get(ring, 2)^, 3)
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testing.expect_value(t, get_last(ring)^, 3)
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// Fill exactly to capacity. Pushing element 7 must make len == cap
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// AND wrap next_write_index from 6 back to 0 in the same step.
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for i in 4 ..= 7 do append(&ring, i)
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testing.expect_value(t, ring.len, 7)
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testing.expect_value(t, ring.next_write_index, 0)
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testing.expect_value(t, start_index_aos(ring), 0)
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testing.expect_value(t, get(ring, 0)^, 1)
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testing.expect_value(t, get(ring, 6)^, 7)
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testing.expect_value(t, get_last(ring)^, 7)
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// First overwrite — oldest element shifts by one.
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append(&ring, 8)
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testing.expect_value(t, ring.len, 7)
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testing.expect_value(t, ring.next_write_index, 1)
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testing.expect_value(t, start_index_aos(ring), 1)
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testing.expect_value(t, get(ring, 0)^, 2)
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testing.expect_value(t, get(ring, 6)^, 8)
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testing.expect_value(t, get_last(ring)^, 8)
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// Stress: 3 more complete wrap cycles (21 more pushes).
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// After 29 total pushes, ring contains the last 7 (23..=29),
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// and next_write_index = 29 mod 7 = 1.
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for i in 9 ..= 29 do append(&ring, i)
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testing.expect_value(t, ring.len, 7)
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testing.expect_value(t, ring.next_write_index, 1)
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testing.expect_value(t, start_index_aos(ring), 1)
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testing.expect_value(t, get(ring, 0)^, 23)
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testing.expect_value(t, get(ring, 3)^, 26)
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testing.expect_value(t, get(ring, 6)^, 29)
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testing.expect_value(t, get_last(ring)^, 29)
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// Clear returns ring to empty-equivalent state.
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clear(&ring)
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testing.expect_value(t, ring.len, 0)
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testing.expect_value(t, ring.next_write_index, 0)
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testing.expect_value(t, start_index_aos(ring), 0)
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// Single-element edge case: get_last(len==1) routes through get(ring, 0).
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append(&ring, 42)
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testing.expect_value(t, ring.len, 1)
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testing.expect_value(t, ring.next_write_index, 1)
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testing.expect_value(t, get(ring, 0)^, 42)
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testing.expect_value(t, get_last(ring)^, 42)
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}
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@(test)
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test_ring_soa_init_from_slice :: proc(t: ^testing.T) {
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Ints :: struct {
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x, y: int,
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}
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// Stack-allocated backing with pre-existing garbage and odd capacity.
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backing: #soa[7]Ints = {{99, 99}, {99, 99}, {99, 99}, {99, 99}, {99, 99}, {99, 99}, {99, 99}}
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ring: Ring_Soa(Ints)
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init_from_slice(&ring, backing[:])
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// Empty ring invariants after init_from_slice.
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testing.expect_value(t, ring.len, 0)
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testing.expect_value(t, ring.next_write_index, 0)
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testing.expect_value(t, start_index_soa(ring), 0)
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// Partial fill (3 / 7).
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for i in 1 ..= 3 do append(&ring, Ints{i, i})
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testing.expect_value(t, ring.len, 3)
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testing.expect_value(t, ring.next_write_index, 3)
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testing.expect_value(t, start_index_soa(ring), 0)
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testing.expect_value(t, get(ring, 0), Ints{1, 1})
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testing.expect_value(t, get(ring, 2), Ints{3, 3})
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testing.expect_value(t, get_last(ring), Ints{3, 3})
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// Fill exactly to capacity. Pushing element 7 must make len == cap
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// AND wrap next_write_index from 6 back to 0 in the same step.
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for i in 4 ..= 7 do append(&ring, Ints{i, i})
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testing.expect_value(t, ring.len, 7)
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testing.expect_value(t, ring.next_write_index, 0)
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testing.expect_value(t, start_index_soa(ring), 0)
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testing.expect_value(t, get(ring, 0), Ints{1, 1})
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testing.expect_value(t, get(ring, 6), Ints{7, 7})
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testing.expect_value(t, get_last(ring), Ints{7, 7})
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// First overwrite — oldest element shifts by one.
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append(&ring, Ints{8, 8})
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testing.expect_value(t, ring.len, 7)
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testing.expect_value(t, ring.next_write_index, 1)
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testing.expect_value(t, start_index_soa(ring), 1)
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testing.expect_value(t, get(ring, 0), Ints{2, 2})
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testing.expect_value(t, get(ring, 6), Ints{8, 8})
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testing.expect_value(t, get_last(ring), Ints{8, 8})
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// Stress: 3 more complete wrap cycles (21 more pushes).
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// After 29 total pushes, ring contains the last 7 (23..=29),
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// and next_write_index = 29 mod 7 = 1.
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for i in 9 ..= 29 do append(&ring, Ints{i, i})
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testing.expect_value(t, ring.len, 7)
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testing.expect_value(t, ring.next_write_index, 1)
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testing.expect_value(t, start_index_soa(ring), 1)
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testing.expect_value(t, get(ring, 0), Ints{23, 23})
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testing.expect_value(t, get(ring, 3), Ints{26, 26})
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testing.expect_value(t, get(ring, 6), Ints{29, 29})
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testing.expect_value(t, get_last(ring), Ints{29, 29})
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// Clear returns ring to empty-equivalent state.
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clear(&ring)
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testing.expect_value(t, ring.len, 0)
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testing.expect_value(t, ring.next_write_index, 0)
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testing.expect_value(t, start_index_soa(ring), 0)
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// Single-element edge case: get_last(len==1) routes through get(ring, 0).
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append(&ring, Ints{42, 42})
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testing.expect_value(t, ring.len, 1)
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testing.expect_value(t, ring.next_write_index, 1)
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testing.expect_value(t, get(ring, 0), Ints{42, 42})
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testing.expect_value(t, get_last(ring), Ints{42, 42})
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}
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