Add vector utility functions

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

3 files changed, 56 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index be1d796..31d88ef 100644
--- a/Makefile
+++ b/Makefile
@@ -104,4 +104,5 @@ OBJECTS += ui-summary.o
 OBJECTS += ui-tag.o
 OBJECTS += ui-tree.o
+OBJECTS += vector.o
 
 ifdef NEEDS_LIBICONV
diff --git a/vector.c b/vector.c
new file mode 100644
index 0000000..0863908
--- a/dev/null
+++ b/vector.c
@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include "vector.h"
+
+static int grow(struct vector *vec, int gently)
+{
+        size_t new_alloc;
+        void *new_data;
+
+        new_alloc = vec->alloc * 3 / 2;
+        if (!new_alloc)
+                new_alloc = 8;
+        new_data = realloc(vec->data, new_alloc * vec->size);
+        if (!new_data) {
+                if (gently)
+                        return ENOMEM;
+                perror("vector.c:grow()");
+                exit(1);
+        }
+        vec->data = new_data;
+        vec->alloc = new_alloc;
+        return 0;
+}
+
+int vector_push(struct vector *vec, const void *data, int gently)
+{
+        int rc;
+
+        if (vec->count == vec->alloc && (rc = grow(vec, gently)))
+                return rc;
+        if (data)
+                memmove(vec->data + vec->count * vec->size, data, vec->size);
+        else
+                memset(vec->data + vec->count * vec->size, 0, vec->size);
+        vec->count++;
+        return 0;
+}
diff --git a/vector.h b/vector.h
new file mode 100644
index 0000000..c64eb1f
--- a/dev/null
+++ b/vector.h
@@ -0,0 +1,17 @@
+#ifndef CGIT_VECTOR_H
+#define CGIT_VECTOR_H
+
+#include <stdlib.h>
+
+struct vector {
+        size_t size;
+        size_t count;
+        size_t alloc;
+        void *data;
+};
+
+#define VECTOR_INIT(type) {sizeof(type), 0, 0, NULL}
+
+int vector_push(struct vector *vec, const void *data, int gently);
+
+#endif /* CGIT_VECTOR_H */