util: implement Jose Fonseca's suggestions for u_buffer.h -> u_dynarray.h

Also describe invariants explicitly and use char* for arithmetic.

1 files changed, 96 insertions, 0 deletions

diff --git a/src/gallium/auxiliary/util/u_dynarray.h b/src/gallium/auxiliary/util/u_dynarray.h
new file mode 100644
index 0000000000..94a882b59e
--- /dev/null
+++ b/src/gallium/auxiliary/util/u_dynarray.h
@@ -0,0 +1,96 @@
+/**************************************************************************
+ *
+ * Copyright 2010 Luca Barbieri
+ *
+ * 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 COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS 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.
+ *
+ **************************************************************************/
+
+#ifndef U_DYNARRAY_H
+#define U_DYNARRAY_H
+
+#include "pipe/p_compiler.h"
+#include "util/u_memory.h"
+
+/* A zero-initialized version of this is guaranteed to represent an
+ * empty array.
+ *
+ * Also, size <= capacity and data != 0 if and only if capacity != 0
+ * capacity will always be the allocation size of data
+ */
+struct util_dynarray
+{
+   void *data;
+   unsigned size;
+   unsigned capacity;
+};
+
+static INLINE void
+util_dynarray_init(struct util_dynarray *buf)
+{
+   memset(buf, 0, sizeof(*buf));
+}
+
+static INLINE void
+util_dynarray_fini(struct util_dynarray *buf)
+{
+   if(buf->data)
+   {
+      FREE(buf->data);
+      util_dynarray_init(buf);
+   }
+}
+
+static INLINE void *
+util_dynarray_grow(struct util_dynarray *buf, int size)
+{
+   unsigned newsize = buf->size + size;
+   char *p;
+   if(newsize > buf->capacity)
+   {
+      unsigned newcap = buf->capacity << 1;
+      if(newsize > newcap)
+	      newcap = newsize;
+      buf->data = REALLOC(buf->data, buf->capacity, newcap);
+      buf->capacity = newcap;
+   }
+
+   p = (char *)buf->data + buf->size;
+   buf->size = newsize;
+   return p;
+}
+
+static INLINE void
+util_dynarray_trim(struct util_dynarray *buf)
+{
+   buf->data = REALLOC(buf->data, buf->capacity, buf->size);
+   buf->capacity = buf->size;
+}
+
+#define util_dynarray_append(buf, type, v) do {type __v = (v); memcpy(util_dynarray_grow((buf), sizeof(type)), &__v, sizeof(type));} while(0)
+#define util_dynarray_top_ptr(buf, type) (type*)((char*)(buf)->data + (buf)->size - sizeof(type))
+#define util_dynarray_top(buf, type) *util_dynarray_top_ptr(buf, type)
+#define util_dynarray_pop_ptr(buf, type) (type*)((char*)(buf)->data + ((buf)->size -= sizeof(type)))
+#define util_dynarray_pop(buf, type) *util_dynarray_pop_ptr(buf, type)
+#define util_dynarray_contains(buf, type) ((buf)->size >= sizeof(type))
+
+#endif /* U_DYNARRAY_H */
+