Vector code

1 files changed, 101 insertions, 0 deletions

diff --git a/src/vector.c b/src/vector.c
new file mode 100644
index 0000000..72b2a4f
--- /dev/null
+++ b/src/vector.c
@@ -0,0 +1,101 @@
+#include "../include/osm/utils.h"
+#include <stdlib.h>
+#include <string.h>
+
+#define VECT_MAX_GROW 1024
+#define VECT_INIT_CAP 4
+
+/**
+ * Initialize a new vector
+ */
+Vector vect_init(unsigned int elsz)
+{
+	Vector out = {
+		.elsz = elsz,
+		.size = VECT_INIT_CAP,
+		.count = 0
+	};
+
+	out.data = malloc(out.elsz * out.size);
+
+	return out;
+}
+
+/**
+ * Unexported function for auto-growing the vector
+ */
+void _vect_grow(Vector *vec)
+{
+	if (vec->elsz == 0)
+	{
+		return;
+	}
+
+	if (vec->size == 0)
+	{
+		vec->size = VECT_INIT_CAP;
+		vec->data = realloc(vec->data, vec->size * vec->elsz);
+		return;
+	}
+
+	if (vec->size > VECT_MAX_GROW)
+	{
+		vec->size += VECT_MAX_GROW;
+	}
+	else
+	{
+		vec->size *= 2;
+	}
+
+	vec->data = realloc(vec->data, vec->size * vec->elsz);
+}
+
+/**
+ * Unexported function for auto-shrinking the vector
+ */
+void _vect_shrink(Vector *vec)
+{
+	if (vec->size == 1)
+	{
+		return;
+	}
+
+	vec->size /= 2;
+	vec->data = realloc(vec->data, vec->size * vec->elsz);
+}
+
+/**
+ * Push a new element to the end of the vector
+ */
+void vect_push(Vector *vec, void *el)
+{
+	memcpy(vec->data + (vec->count * vec->elsz), el, vec->elsz);
+	vec->count++;
+
+	if (vec->size == vec->count)
+	{
+		_vect_grow(vec);
+	}
+}
+
+/**
+ * Pop an element off of the end of the vector
+ */
+void vect_pop(Vector *vec)
+{
+	vec->count--;
+	
+	if (vec->count < vec->size / 3)
+	{
+		_vect_shrink(vec);
+	}
+}
+
+void vect_end(Vector *vec)
+{
+	vec->size = 0;
+	vec->count = 0;
+	vec->elsz = 0;
+	free(vec->data);
+	vec->data = NULL;
+}