initial checkout from wrc

1 files changed, 64 insertions, 0 deletions

diff --git a/kernel/list.c b/kernel/list.c
new file mode 100644
index 0000000..084000a
--- /dev/null
+++ b/kernel/list.c
@@ -0,0 +1,64 @@
+/**
+** @file list.c
+**
+** @author Warren R. Carithers
+**
+** @brief	Support for a basic linked list data type.
+**
+** This module provides a very basic linked list data structure.
+** A list can contain anything that has a pointer field in the first
+** four bytes; these routines assume those bytes contain a pointer to
+** the following entry in the list, whatever that may be.
+*/
+
+#define KERNEL_SRC
+
+#include <common.h>
+
+#include <list.h>
+
+/*
+** FUNCTIONS
+*/
+
+/**
+** Name:    list_add
+**
+** Add the supplied data to the beginning of the specified list.
+**
+** @param[in,out] list  The address of a list_t variable
+** @param[in] data      The data to prepend to the list
+*/
+void list_add( list_t *list, void *data ) {
+
+	// sanity checks
+	assert1( list != NULL );
+	assert1( data != NULL );
+
+	list_t *tmp = (list_t *)data;
+	tmp->next = list->next;
+	list->next = tmp;
+}
+
+/**
+** Name:    list_remove
+**
+** Remove the first entry from a linked list.
+**
+** @param[in,out] list  The address of a list_t variable
+**
+** @return a pointer to the removed data, or NULL if the list was empty
+*/
+void *list_remove( list_t *list ) {
+
+	assert1( list != NULL );
+
+	list_t *data = list->next;
+	if( data != NULL ) {
+		list->next = data->next;
+		data->next = NULL;
+	}
+
+	return (void *)data;
+}
+