Add truncate to vectors

3 files changed, 43 insertions, 1 deletions

diff --git a/collections/vector/vector.adoc b/collections/vector/vector.adoc
index d423c37..e3fa94a 100644
--- a/collections/vector/vector.adoc
+++ b/collections/vector/vector.adoc
@@ -1,7 +1,7 @@
 Vector
 ======
 Tucker Evans
-v0.14, 2020-07-03
+v0.15, 2020-07-04
 
 A basic vector, that hold pointers to your data structures.
 
@@ -367,6 +367,36 @@ assert(str_cmp(vec_back(vector, str2) == 0);
 assert(vec_size == 2);
 ----
 
+[[vec_truncate]]
++void vec_truncate(vec *self, int size)+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Truncates vector +self+ to +size+ elements, elements in positions > +size+ will
+no longer be accessable through +self+. Does nothing if +size+ > current number
+of elements.
+
+NOTE: Does not currently reduce memory footprint
+
+Examples
+^^^^^^^^
+[source,c]
+----
+#include "vector.h"
+#include <string.h>
+
+char *str1 = "ONE";
+char *str2 = "TWO";
+char *str3 = "THREE";
+
+vec *vector = vec_new();
+vec_push(vector, str_dup(str1));
+vec_push(vector, str_dup(str2));
+vec_push(vector, str_dup(str3));
+
+vec_truncate(vector, 1);
+
+assert(vec_size == 1);
+----
+
 [[vec_clear]]
 +void vec_clear(vec *self)+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/collections/vector/vector.c b/collections/vector/vector.c
index 5c473a4..c456d8a 100644
--- a/collections/vector/vector.c
+++ b/collections/vector/vector.c
@@ -237,6 +237,16 @@ int i;
 	return vec_pop(root);
 }
 
+void vec_truncate(root, size)
+vec *root;
+int size;
+{
+	if (!root || size < 0 || size >= root->end)
+		return;
+
+	root->end = size;
+}
+
 void vec_clear(root)
 vec *root;
 {
diff --git a/collections/vector/vector.h b/collections/vector/vector.h
index 083a1d0..b997b46 100644
--- a/collections/vector/vector.h
+++ b/collections/vector/vector.h
@@ -29,6 +29,8 @@ void* vec_swap_pop(vec*, int);
 
 
 /*memory*/
+void vec_truncate(vec*, int);
+
 void vec_clear(vec*);
 void vec_free(vec*);
 #endif