utils: add utility dynamic array

Add utility code to handle a dynamic array.
Supported operations:
* append an item
* grow the array
* get an item
* get the length of the array
* check if the array has any data on it.

There are clear use cases for this utility in the OrcParser,
but may be useful elsewhere as well.

Part-of: <https://gitlab.freedesktop.org/gstreamer/orc/-/merge_requests/30>

2 files changed, 51 insertions, 0 deletions

diff --git a/orc/orcutils.c b/orc/orcutils.c
index f0b77f6..adbb5ad 100644
--- a/orc/orcutils.c
+++ b/orc/orcutils.c
@@ -206,3 +206,34 @@ _strtoll (const char *nptr, char **endptr, int base)
   return (neg) ? - val : val;
 }
 
+int
+orc_vector_length (OrcVector *vector)
+{
+  return (vector == NULL) ?0 :vector->n_items;
+}
+
+int
+orc_vector_has_data (OrcVector *vector)
+{
+  return (orc_vector_length (vector) > 0 &&
+          vector->items != NULL && /* extra sanity check */
+          vector->items[0] != NULL);
+}
+
+void
+orc_vector_extend (OrcVector *vector)
+{
+  vector->n_items_alloc += ORC_VECTOR_ITEM_CHUNK;
+  vector->items = realloc (vector->items, sizeof(void *) * vector->n_items_alloc);
+}
+
+void
+orc_vector_append (OrcVector *vector, void *item)
+{
+  if (vector->n_items == vector->n_items_alloc) {
+    orc_vector_extend (vector);
+  }
+  vector->items[vector->n_items] = item;
+  vector->n_items++;
+}
+
diff --git a/orc/orcutils.h b/orc/orcutils.h
index c20e27f..9b1f993 100644
--- a/orc/orcutils.h
+++ b/orc/orcutils.h
@@ -231,6 +231,26 @@ ORC_BEGIN_DECLS
 char * get_proc_cpuinfo (void);
 #endif
 
+#define ORC_VECTOR_ITEM_CHUNK 32
+
+typedef struct _OrcVector OrcVector;
+struct _OrcVector {
+  void **items;
+  int n_items;
+  int n_items_alloc;
+};
+
+#define ORC_VECTOR_AS_TYPE(VECTOR, TYPE) \
+    ((TYPE **)(((VECTOR)->items)))
+
+#define ORC_VECTOR_GET_ITEM(VECTOR, INDEX, TYPEPTR) \
+    ((TYPEPTR) &((VECTOR)->items[(INDEX)]))
+
+void orc_vector_extend (OrcVector *vector);
+void orc_vector_append (OrcVector *vector, void *item);
+int orc_vector_length (OrcVector *vector);
+int orc_vector_has_data (OrcVector *vector);
+
 char * _strndup (const char *s, int n);
 char ** strsplit (const char *s, char delimiter);
 char * get_tag_value (char *s, const char *tag);