Add constructor for maps

3 files changed, 40 insertions, 1 deletions

diff --git a/collections/map/map.adoc b/collections/map/map.adoc
index a43ae1d..fc6b8b7 100644
--- a/collections/map/map.adoc
+++ b/collections/map/map.adoc
@@ -1,7 +1,7 @@
 Map
 ===
 Tucker Evans
-v0.0, 2020-07-06
+v0.1, 2020-07-06
 
 A basic map implemented in an AVL tree.
 
@@ -30,3 +30,23 @@ first parameter.
 This is a pointer to a function that to compare keys from pointers. This
 typedef is provided to cast comparison functions as a map expects the
 comparison function to take void* as its parameters.
+
+Functions
+---------
+[[map_new]]
++map_new(cmp_func cmp)+
+~~~~~~~~~~~~~~~~~~~~~~~
+Constructs an empty map.
++cmp+ should be a function that takes two pointers (+lhs+, +rhs+)to your value
+type and returns (int) a negative value if +lhs+ is less than  +rhs+, zero if
++lhs+ is equal to +rhs+, and positive value if +lhs+ is greater than +rhs+.
+
+Examples
+^^^^^^^^
+[source,c]
+----
+#include "map.h"
+#include <string.h>
+
+map *dict = map_new((cmp_func) strcmp);
+----
diff --git a/collections/map/map.c b/collections/map/map.c
index 21af21c..803b5ad 100644
--- a/collections/map/map.c
+++ b/collections/map/map.c
@@ -1,7 +1,9 @@
 #include "map.h"
 
 #include <string.h>
+#include <stdlib.h>
 #include <stdio.h>
+#include <assert.h>
 
 struct map_node {
 	void *key, *val;
@@ -9,3 +11,17 @@ struct map_node {
 
 	struct map_node *left, *right, *parent;
 };
+
+map* map_new(cmp)
+cmp_func cmp;
+{
+	map *tmp;
+
+	tmp = malloc(sizeof(map));
+	assert(tmp);
+
+	tmp->cmp = cmp;
+	tmp->key = tmp->val = tmp->left = tmp->right = tmp->parent = NULL;
+
+	return tmp;
+}
diff --git a/collections/map/map.h b/collections/map/map.h
index a760b45..8aad2f4 100644
--- a/collections/map/map.h
+++ b/collections/map/map.h
@@ -4,4 +4,7 @@
 typedef struct map_node map;
 typedef int (*cmp_func)(void*, void*);
 
+/*constructors*/
+map* map_new(cmp_func);
+
 #endif