container/queue: Document the package

core/container/queue/queue.odin

@@ -4,7 +4,13 @@ import "base:builtin"
 import "base:runtime"
 _ :: runtime
 
-// Dynamically resizable double-ended queue/ring-buffer
+/*
+`Queue` is a dynamically resizable double-ended queue/ring-buffer.
+
+Being double-ended means that either end may be pushed onto or popped from
+across the same block of memory, in any order, thus providing both stack and
+queue-like behaviors in the same data structure.
+*/
 Queue :: struct($T: typeid) {
 	data:   [dynamic]T,
 	len:    uint,
@@ -13,7 +19,9 @@ Queue :: struct($T: typeid) {
 
 DEFAULT_CAPACITY :: 16
 
-// Procedure to initialize a queue
+/*
+Initialize a `Queue` with a starting `capacity` and an `allocator`.
+*/
 init :: proc(q: ^$Q/Queue($T), capacity := DEFAULT_CAPACITY, allocator := context.allocator) -> runtime.Allocator_Error {
 	if q.data.allocator.procedure == nil {
 		q.data.allocator = allocator
@@ -22,9 +30,17 @@ init :: proc(q: ^$Q/Queue($T), capacity := DEFAULT_CAPACITY, allocator := contex
 	return reserve(q, capacity)
 }
 
-// Procedure to initialize a queue from a fixed backing slice.
+/*
-// The contents of the `backing` will be overwritten as items are pushed onto the `Queue`.
+Initialize a `Queue` from a fixed `backing` slice into which modifications are
-// Any previous contents are not available.
+made directly.
+
+The contents of the `backing` will be overwritten as items are pushed onto the
+`Queue`. Any previous contents will not be available through the API but are
+not explicitly zeroed either.
+
+Note that procedures which need space to work (`push_back`, ...) will fail if
+the backing slice runs out of space.
+*/
 init_from_slice :: proc(q: ^$Q/Queue($T), backing: []T) -> bool {
 	clear(q)
 	q.data = transmute([dynamic]T)runtime.Raw_Dynamic_Array{
@@ -36,8 +52,14 @@ init_from_slice :: proc(q: ^$Q/Queue($T), backing: []T) -> bool {
 	return true
 }
 
-// Procedure to initialize a queue from a fixed backing slice.
+/*
-// Existing contents are preserved and available on the queue.
+Initialize a `Queue` from a fixed `backing` slice into which modifications are
+made directly.
+
+The contents of the queue will start out with all of the elements in `backing`,
+effectively creating a full queue from the slice. As such, no procedures will
+be able to add more elements to the queue until some are taken off.
+*/
 init_with_contents :: proc(q: ^$Q/Queue($T), backing: []T) -> bool {
 	clear(q)
 	q.data = transmute([dynamic]T)runtime.Raw_Dynamic_Array{
@@ -50,27 +72,45 @@ init_with_contents :: proc(q: ^$Q/Queue($T), backing: []T) -> bool {
 	return true
 }
 
-// Procedure to destroy a queue
+/*
+Delete memory that has been dynamically allocated from a `Queue` that was setup with `init`.
+
+Note that this procedure should not be used on queues setup with
+`init_from_slice` or `init_with_contents`, as neither of those procedures keep
+track of the allocator state of the underlying `backing` slice.
+*/
 destroy :: proc(q: ^$Q/Queue($T)) {
 	delete(q.data)
 }
 
-// The length of the queue
+/*
+Return the length of the queue.
+*/
 len :: proc(q: $Q/Queue($T)) -> int {
 	return int(q.len)
 }
 
-// The current capacity of the queue
+/*
+Return the capacity of the queue.
+*/
 cap :: proc(q: $Q/Queue($T)) -> int {
 	return builtin.len(q.data)
 }
 
-// Remaining space in the queue (cap-len)
+/*
+Return the remaining space in the queue.
+
+This will be `cap() - len()`.
+*/
 space :: proc(q: $Q/Queue($T)) -> int {
 	return builtin.len(q.data) - int(q.len)
 }
 
-// Reserve enough space for at least the specified capacity
+/*
+Reserve enough space in the queue for at least the specified capacity.
+
+This may return an error if allocation failed.
+*/
 reserve :: proc(q: ^$Q/Queue($T), capacity: int) -> runtime.Allocator_Error {
 	if capacity > space(q^) {
 		return _grow(q, uint(capacity)) 
@@ -78,7 +118,11 @@ reserve :: proc(q: ^$Q/Queue($T), capacity: int) -> runtime.Allocator_Error {
 	return nil
 }
 
+/*
+Get the element at index `i`.
 
+This will raise a bounds checking error if `i` is an invalid index.
+*/
 get :: proc(q: ^$Q/Queue($T), #any_int i: int, loc := #caller_location) -> T {
 	runtime.bounds_check_error_loc(loc, i, int(q.len))
 
@@ -86,6 +130,11 @@ get :: proc(q: ^$Q/Queue($T), #any_int i: int, loc := #caller_location) -> T {
 	return q.data[idx]
 }
 
+/*
+Get a pointer to the element at index `i`.
+
+This will raise a bounds checking error if `i` is an invalid index.
+*/
 get_ptr :: proc(q: ^$Q/Queue($T), #any_int i: int, loc := #caller_location) -> ^T {
 	runtime.bounds_check_error_loc(loc, i, int(q.len))
 	
@@ -93,6 +142,11 @@ get_ptr :: proc(q: ^$Q/Queue($T), #any_int i: int, loc := #caller_location) -> ^
 	return &q.data[idx]
 }
 
+/*
+Set the element at index `i` to `val`.
+
+This will raise a bounds checking error if `i` is an invalid index.
+*/
 set :: proc(q: ^$Q/Queue($T), #any_int i: int, val: T, loc := #caller_location) {
 	runtime.bounds_check_error_loc(loc, i, int(q.len))
 	
@@ -100,6 +154,11 @@ set :: proc(q: ^$Q/Queue($T), #any_int i: int, val: T, loc := #caller_location)
 	q.data[idx] = val
 }
 
+/*
+Get the element at the front of the queue.
+
+This will raise a bounds checking error if the queue is empty.
+*/
 front :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> T {
 	when !ODIN_NO_BOUNDS_CHECK {
 		ensure(q.len > 0, "Queue is empty.", loc)
@@ -107,6 +166,11 @@ front :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> T {
 	return q.data[q.offset]
 }
 
+/*
+Get a pointer to the element at the front of the queue.
+
+This will raise a bounds checking error if the queue is empty.
+*/
 front_ptr :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> ^T {
 	when !ODIN_NO_BOUNDS_CHECK {
 		ensure(q.len > 0, "Queue is empty.", loc)
@@ -114,6 +178,11 @@ front_ptr :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> ^T {
 	return &q.data[q.offset]
 }
 
+/*
+Get the element at the back of the queue.
+
+This will raise a bounds checking error if the queue is empty.
+*/
 back :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> T {
 	when !ODIN_NO_BOUNDS_CHECK {
 		ensure(q.len > 0, "Queue is empty.", loc)
@@ -121,6 +190,12 @@ back :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> T {
 	idx := (q.offset+uint(q.len - 1))%builtin.len(q.data)
 	return q.data[idx]
 }
+
+/*
+Get a pointer to the element at the back of the queue.
+
+This will raise a bounds checking error if the queue is empty.
+*/
 back_ptr :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> ^T {
 	when !ODIN_NO_BOUNDS_CHECK {
 		ensure(q.len > 0, "Queue is empty.", loc)
@@ -140,7 +215,30 @@ peek_back :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> ^T {
 	return back_ptr(q, loc)
 }
 
-// Push an element to the back of the queue
+/*
+Push an element to the back of the queue.
+
+If there is no more space left and allocation fails to get more, this will
+return false with an `Allocator_Error`.
+
+Example:
+
+	import "base:runtime"
+	import "core:container/queue"
+
+	// This demonstrates typical queue behavior (First-In First-Out).
+	main :: proc() {
+		q: queue.Queue(int)
+		queue.init(&q)
+		queue.push_back(&q, 1)
+		queue.push_back(&q, 2)
+		queue.push_back(&q, 3)
+		// q.data is now [1, 2, 3, ...]
+		assert(queue.pop_front(&q) == 1)
+		assert(queue.pop_front(&q) == 2)
+		assert(queue.pop_front(&q) == 3)
+	}
+*/
 push_back :: proc(q: ^$Q/Queue($T), elem: T) -> (ok: bool, err: runtime.Allocator_Error) {
 	if space(q^) == 0 {
 		_grow(q) or_return
@@ -151,7 +249,30 @@ push_back :: proc(q: ^$Q/Queue($T), elem: T) -> (ok: bool, err: runtime.Allocato
 	return true, nil
 }
 
-// Push an element to the front of the queue
+/*
+Push an element to the front of the queue.
+
+If there is no more space left and allocation fails to get more, this will
+return false with an `Allocator_Error`.
+
+Example:
+
+	import "base:runtime"
+	import "core:container/queue"
+
+	// This demonstrates stack behavior (First-In Last-Out).
+	main :: proc() {
+		q: queue.Queue(int)
+		queue.init(&q)
+		queue.push_back(&q, 1)
+		queue.push_back(&q, 2)
+		queue.push_back(&q, 3)
+		// q.data is now [1, 2, 3, ...]
+		assert(queue.pop_back(&q) == 3)
+		assert(queue.pop_back(&q) == 2)
+		assert(queue.pop_back(&q) == 1)
+	}
+*/
 push_front :: proc(q: ^$Q/Queue($T), elem: T) -> (ok: bool, err: runtime.Allocator_Error)  {
 	if space(q^) == 0 {
 		_grow(q) or_return
@@ -162,8 +283,30 @@ push_front :: proc(q: ^$Q/Queue($T), elem: T) -> (ok: bool, err: runtime.Allocat
 	return true, nil
 }
 
+/*
+Pop an element from the back of the queue.
 
-// Pop an element from the back of the queue
+This will raise a bounds checking error if the queue is empty.
+
+Example:
+
+	import "base:runtime"
+	import "core:container/queue"
+
+	// This demonstrates stack behavior (First-In Last-Out) at the far end of the data array.
+	main :: proc() {
+		q: queue.Queue(int)
+		queue.init(&q)
+		queue.push_front(&q, 1)
+		queue.push_front(&q, 2)
+		queue.push_front(&q, 3)
+		// q.data is now [..., 3, 2, 1]
+		log.infof("%#v", q)
+		assert(queue.pop_front(&q) == 3)
+		assert(queue.pop_front(&q) == 2)
+		assert(queue.pop_front(&q) == 1)
+	}
+*/
 pop_back :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> (elem: T) {
 	when !ODIN_NO_BOUNDS_CHECK {
 		ensure(q.len > 0, "Queue is empty.", loc)
@@ -173,7 +316,11 @@ pop_back :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> (elem: T) {
 	elem = q.data[idx]
 	return
 }
-// Safely pop an element from the back of the queue
+
+/*
+Pop an element from the back of the queue if one exists and return true.
+Otherwise, return a nil element and false.
+*/
 pop_back_safe :: proc(q: ^$Q/Queue($T)) -> (elem: T, ok: bool) {
 	if q.len > 0 {
 		q.len -= 1
@@ -184,7 +331,11 @@ pop_back_safe :: proc(q: ^$Q/Queue($T)) -> (elem: T, ok: bool) {
 	return
 }
 
-// Pop an element from the front of the queue
+/*
+Pop an element from the front of the queue
+
+This will raise a bounds checking error if the queue is empty.
+*/
 pop_front :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> (elem: T) {
 	when !ODIN_NO_BOUNDS_CHECK {
 		ensure(q.len > 0, "Queue is empty.", loc)
@@ -194,7 +345,11 @@ pop_front :: proc(q: ^$Q/Queue($T), loc := #caller_location) -> (elem: T) {
 	q.len -= 1
 	return
 }
-// Safely pop an element from the front of the queue
+
+/*
+Pop an element from the front of the queue if one exists and return true.
+Otherwise, return a nil element and false.
+*/
 pop_front_safe :: proc(q: ^$Q/Queue($T)) -> (elem: T, ok: bool) {
 	if q.len > 0 {
 		elem = q.data[q.offset]
@@ -205,7 +360,12 @@ pop_front_safe :: proc(q: ^$Q/Queue($T)) -> (elem: T, ok: bool) {
 	return
 }
 
-// Push multiple elements to the back of the queue
+/*
+Push many elements at once to the back of the queue.
+
+If there is not enough space left and allocation fails to get more, this will
+return false with an `Allocator_Error`.
+*/
 push_back_elems :: proc(q: ^$Q/Queue($T), elems: ..T) -> (ok: bool, err: runtime.Allocator_Error)  {
 	n := uint(builtin.len(elems))
 	if space(q^) < int(n) {
@@ -224,7 +384,11 @@ push_back_elems :: proc(q: ^$Q/Queue($T), elems: ..T) -> (ok: bool, err: runtime
 	return true, nil
 }
 
-// Consume `n` elements from the front of the queue
+/*
+Consume `n` elements from the back of the queue.
+
+This will raise a bounds checking error if the queue does not have enough elements.
+*/
 consume_front :: proc(q: ^$Q/Queue($T), n: int, loc := #caller_location) {
 	when !ODIN_NO_BOUNDS_CHECK {
 		ensure(q.len >= uint(n), "Queue does not have enough elements to consume.", loc)
@@ -236,7 +400,11 @@ consume_front :: proc(q: ^$Q/Queue($T), n: int, loc := #caller_location) {
 	}
 }
 
-// Consume `n` elements from the back of the queue
+/*
+Consume `n` elements from the back of the queue.
+
+This will raise a bounds checking error if the queue does not have enough elements.
+*/
 consume_back :: proc(q: ^$Q/Queue($T), n: int, loc := #caller_location) {
 	when !ODIN_NO_BOUNDS_CHECK {
 		ensure(q.len >= uint(n), "Queue does not have enough elements to consume.", loc)
@@ -254,7 +422,10 @@ push   :: proc{push_back, push_back_elems}
 append :: proc{push_back, push_back_elems}
 
 
-// Clear the contents of the queue
+/*
+Reset the queue's length and offset to zero, letting it write new elements over
+old memory, in effect clearing the accessible contents.
+*/
 clear :: proc(q: ^$Q/Queue($T)) {
 	q.len = 0
 	q.offset = 0