lib/vec: Add igt_vec

Add a small std::vector lookalike which grows as needed.

v2: Reorganize things into igt_vec_grow() (Chris)
    Trust that memmove(..., 0) works (Chris)

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

1 files changed, 89 insertions, 0 deletions

diff --git a/lib/igt_vec.c b/lib/igt_vec.c
new file mode 100644
index 00000000..591e56fa
--- /dev/null
+++ b/lib/igt_vec.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright © 2020 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "igt_core.h"
+#include "igt_vec.h"
+
+void igt_vec_init(struct igt_vec *vec, int elem_size)
+{
+	memset(vec, 0, sizeof(*vec));
+	vec->elem_size = elem_size;
+}
+
+void igt_vec_fini(struct igt_vec *vec)
+{
+	free(vec->elems);
+	memset(vec, 0, sizeof(*vec));
+}
+
+void *igt_vec_elem(const struct igt_vec *vec, int idx)
+{
+	igt_assert(idx < vec->len);
+
+	return vec->elems + idx * vec->elem_size;
+}
+
+static void *igt_vec_grow(struct igt_vec *vec)
+{
+	if (vec->len++ >= vec->size) {
+		vec->size = vec->size ? vec->size * 2 : 8;
+		vec->elems = realloc(vec->elems, vec->size * vec->elem_size);
+		igt_assert(vec->elems);
+	}
+
+	return igt_vec_elem(vec, vec->len - 1);
+}
+
+void igt_vec_push(struct igt_vec *vec, void *elem)
+{
+	memcpy(igt_vec_grow(vec), elem, vec->elem_size);
+}
+
+int igt_vec_length(const struct igt_vec *vec)
+{
+	return vec->len;
+}
+
+int igt_vec_index(const struct igt_vec *vec, void *elem)
+{
+	for (int i = 0; i < vec->len; i++) {
+		if (!memcmp(igt_vec_elem(vec, i), elem, vec->elem_size))
+			return i;
+	}
+
+	return -1;
+}
+
+void igt_vec_remove(struct igt_vec *vec, int idx)
+{
+	igt_assert(idx < vec->len);
+
+	memmove(igt_vec_elem(vec, idx),
+		igt_vec_elem(vec, idx + 1),
+		(vec->len - 1 - idx) * vec->elem_size);
+
+	vec->len--;
+}