From 72cb2e77024970509ff403670f9e4245bcefebd6 Mon Sep 17 00:00:00 2001
From: Tucker Evans <tucker@tuckerevans.com>
Date: Fri, 3 Jul 2020 01:05:09 -0400
Subject: Add swap function to vectors

---
 collections/vector/vector.adoc | 28 +++++++++++++++++++++++++++-
 collections/vector/vector.c    | 16 ++++++++++++++++
 collections/vector/vector.h    |  3 +++
 3 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/collections/vector/vector.adoc b/collections/vector/vector.adoc
index 0409b05..cc83375 100644
--- a/collections/vector/vector.adoc
+++ b/collections/vector/vector.adoc
@@ -1,7 +1,7 @@
 Vector
 ======
 Tucker Evans
-v0.10, 2020-07-03
+v0.11, 2020-07-03
 
 A basic vector, that hold pointers to your data structures.
 
@@ -257,6 +257,32 @@ vec_push(vector, str_dup(str3));
 assert(str_cmp(vec_index(vector, 1), str2) == 0);
 ----
 
+[[vec_swap]]
++void vec_swap(vec *self, int i, int j)+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Swaps elements at positions +i+ and +j+, does nothing if +i+ or +j+ are out of
+bounds.
+
+Examples
+^^^^^^^^
+[source,c]
+----
+#include "dvector.h"
+#include <string.h>
+
+char *str1 = "ONE";
+char *str2 = "TWO";
+
+vec *vector = vec_new();
+vec_push(vector, str_dup(str1));
+vec_push(vector, str_dup(str2));
+
+vec_swap(vector, 0, 1);
+
+assert(str_cmp(vec_index(vector, 0), str2) == 0);
+assert(str_cmp(vec_back(vector), str1) == 0);
+----
+
 [[vec_clear]]
 +void vec_clear(vec *self)+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/collections/vector/vector.c b/collections/vector/vector.c
index 5cb56ef..a7e0845 100644
--- a/collections/vector/vector.c
+++ b/collections/vector/vector.c
@@ -174,6 +174,22 @@ int index;
 	return root->base[index];
 }
 
+void vec_swap(root, i, j)
+vec *root;
+int i,j;
+{
+	void *tmp;
+
+	if (!root || i >= root->end || i < 0 || j >= root->end || j < 0)
+		return;
+
+	tmp = root->base[i];
+	root->base[i] = root->base[j];
+	root->base[j] = tmp;
+
+	return;
+}
+
 void vec_clear(root)
 vec *root;
 {
diff --git a/collections/vector/vector.h b/collections/vector/vector.h
index 7d38694..2b1e8e9 100644
--- a/collections/vector/vector.h
+++ b/collections/vector/vector.h
@@ -21,6 +21,9 @@ void* vec_back(vec*);
 void vec_set(vec*, int, void*);
 void* vec_index(vec*, int);
 
+void vec_swap(vec*, int, int);
+
+
 /*memory*/
 void vec_clear(vec*);
 void vec_free(vec*);
-- 
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