added linked lists in lib/data-types

src/lib/data-types.h

@@ -12,6 +12,7 @@
 
 	#include <stddef.h>
 	#include <stdint.h>
+	#include "data-types/linked-list.h"
 
 	#define bool _Bool
 	#define true  ((bool)1)

src/lib/data-types/linked-list.c

@@ -0,0 +1,156 @@
+/* ----------------------------------------------------------------------------
+ * linked list
+ * ----------------------------------------------------------------------------
+ * Copyright (c) 2012 Ben Blazak <benblazak.dev@gmail.com>
+ * Released under The MIT License (MIT) (see "license.md")
+ * Project located at <https://github.com/benblazak/ergodox-firmware>
+ * ------------------------------------------------------------------------- */
+
+
+#include <stdlib.h>
+#include "lib/data-types.h"
+
+#include "linked-list.h"
+
+
+// convenience macros (undefined later)
+#define _NEW_STRUCT_POINTER(type, name)	\
+	struct type * name = (struct type *) malloc(sizeof(struct type))
+
+
+struct linked_list * linked_list_new(void) {
+	_NEW_STRUCT_POINTER(linked_list, list);
+	if (!list) return NULL;
+
+	list->head = NULL;
+	list->tail = NULL;
+
+	list->number_of_elements = 0;
+	return list;
+}
+
+struct linked_list * linked_list_add_head(
+		struct linked_list * list,
+		LINKED_LIST_DATA_TYPE data ) {
+
+	_NEW_STRUCT_POINTER(linked_list_node, node);
+	if (!node) return NULL;
+
+	node->data = data;
+	node->next = list->head;
+	list->head = node;
+	if (list->number_of_elements == 0)
+		list->tail = node;
+
+	list->number_of_elements++;
+	return list;
+}
+
+struct linked_list * linked_list_add_tail(
+		struct linked_list * list,
+		LINKED_LIST_DATA_TYPE data ) {
+
+	_NEW_STRUCT_POINTER(linked_list_node, node);
+	if (!node) return NULL;
+
+	node->data = data;
+	node->next = NULL;
+	if (list->number_of_elements == 0)
+		list->head = node;
+	else
+		list->tail->next = node;
+	list->tail = node;
+
+	list->number_of_elements++;
+	return list;
+}
+
+LINKED_LIST_DATA_TYPE linked_list_pop_head(struct linked_list * list) {
+	if (list->number_of_elements == 0)
+		return 0;
+
+	struct linked_list_node node = {
+		.data = list->head->data,
+		.next = list->head->next
+	};
+
+	free(list->head);
+
+	if (list->number_of_elements == 1) {
+		list->head = NULL;
+		list->tail = NULL;
+	} else {
+		list->head = node.next;
+	}
+
+	list->number_of_elements--;
+	return node.data;
+}
+
+// note: this function is inefficient for singly linked lists: it has O(n) time
+// instead of O(1) time like most of the other functions.  but it's not needed
+// for implementing stacks or queues, so i don't anticipate it being used all
+// that much.  it's here for completeness.
+LINKED_LIST_DATA_TYPE linked_list_pop_tail(struct linked_list * list) {
+	if (list->number_of_elements == 0)
+		return 0;
+
+	struct linked_list_node node = {
+		.data = list->tail->data,
+		.next = list->tail->next
+	};
+
+	free(list->tail);
+
+	if (list->number_of_elements == 1) {
+		list->head = NULL;
+		list->tail = NULL;
+	} else {
+		list->tail = list->head;
+		for (uint8_t i=2; i<(list->number_of_elements); i++)
+			list->tail = list->tail->next;
+		list->tail->next = NULL;
+	}
+
+	list->number_of_elements--;
+	return node.data;
+}
+
+LINKED_LIST_DATA_TYPE linked_list_read(
+			struct linked_list * list,
+			uint8_t position ) {
+
+	if (position < 1 || position > (list->number_of_elements))
+		return 0;
+
+	struct linked_list_node * node = list->head;
+	for (uint8_t i=1; i<position; i++)
+		node = node->next;
+
+	return node->data;
+}
+
+struct linked_list * linked_list_copy(struct linked_list * list) {
+	_NEW_STRUCT_POINTER(linked_list, copy);
+
+	for (uint8_t i=1; i<=(list->number_of_elements); i++)
+		linked_list_add_tail(copy, linked_list_read(list, i));
+
+	return copy;
+}
+
+
+// note: this is implemented inefficiently (using ...pop_head(), which does
+// extra work).  but that makes things simpler, and i don't anticipate using it
+// all that often.
+void linked_list_free(struct linked_list * list) {
+	while ((list->number_of_elements) > 0)
+		linked_list_pop_head(list);
+
+	free(list);
+}
+
+
+// convenience macros (undefined here)
+#undef _NEW_STRUCT_POINTER
+

src/lib/data-types/linked-list.h

@@ -0,0 +1,86 @@
+/* ----------------------------------------------------------------------------
+ * linked list : exports
+ *
+ * Includes aliases to treat the list as a queue or stack.
+ * ----------------------------------------------------------------------------
+ * Copyright (c) 2012 Ben Blazak <benblazak.dev@gmail.com>
+ * Released under The MIT License (MIT) (see "license.md")
+ * Project located at <https://github.com/benblazak/ergodox-firmware>
+ * ------------------------------------------------------------------------- */
+
+
+#ifndef LINKED_LIST_h
+	#define LINKED_LIST_h
+
+	#include "lib/data-types.h"
+
+
+	// default list data type
+	#ifndef LINKED_LIST_DATA_TYPE
+		#define LINKED_LIST_DATA_TYPE uint8_t
+	#endif
+
+
+	// structs
+	struct linked_list_node {
+		LINKED_LIST_DATA_TYPE data;
+		struct linked_list_node * next;
+	};
+
+	struct linked_list{
+		uint8_t number_of_elements;
+		struct linked_list_node * head;
+		struct linked_list_node * tail;
+	};
+
+	// functions
+	struct linked_list * linked_list_new(void);
+	struct linked_list * linked_list_add_head(
+			struct linked_list * list,
+			LINKED_LIST_DATA_TYPE data );
+	struct linked_list * linked_list_add_tail(
+			struct linked_list * list,
+			LINKED_LIST_DATA_TYPE data );
+	LINKED_LIST_DATA_TYPE linked_list_pop_head(struct linked_list * list);
+	LINKED_LIST_DATA_TYPE linked_list_pop_tail(struct linked_list * list);
+	LINKED_LIST_DATA_TYPE linked_list_read(
+			struct linked_list * list,
+			uint8_t position );
+	struct linked_list * linked_list_copy(struct linked_list * list);
+	void linked_list_free(struct linked_list * list);
+
+
+	// typedefs, for user code
+	typedef struct linked_list * linked_list_t;
+	typedef struct linked_list_node * linked_list_node_t;
+
+	// aliases, for user code
+	#define list_t        linked_list_t
+	#define list_new      linked_list_new
+	#define list_push     linked_list_add_head
+	#define list_append   linked_list_add_tail
+	#define list_pop      linked_list_pop_head
+	#define list_pop_tail linked_list_pop_tail
+	#define list_read     linked_list_read
+	#define list_copy     linked_list_copy
+	#define list_free     linked_list_free
+
+	#define queue_t      list_t
+	#define queue_new    list_new
+	#define queue_append list_append
+	#define queue_pop    list_pop
+	#define queue_read   list_read
+	#define queue_copy   list_copy
+	#define queue_free   list_free
+
+	#define stack_t    list_t
+	#define stack_new  list_new
+	#define stack_push list_push
+	#define stack_pop  list_pop
+	#define stack_read list_read
+	#define stack_copy list_copy
+	#define stack_free list_free
+
+
+#endif
+