gallium/auxiliary: add dynamically sized buffer/array/vector

src/gallium/auxiliary/util/u_buffer.h

@@ -0,0 +1,57 @@
+#ifndef U_BUFFER_H
+#define U_BUFFER_H
+
+struct util_buffer
+{
+	void* data;
+	unsigned size;
+	unsigned capacity;
+};
+
+static inline void
+util_buffer_init(struct util_buffer* buf)
+{
+	memset(buf, 0, sizeof(*buf));
+}
+
+static inline  void
+util_buffer_fini(struct util_buffer* buf)
+{
+	if(buf->data) {
+		free(buf->data);
+		util_buffer_init(buf);
+	}
+}
+
+static inline void*
+util_buffer_grow(struct util_buffer* buf, int size)
+{
+	unsigned newsize = buf->size + size;
+	char* p;
+	if(newsize > buf->capacity) {
+		buf->capacity <<= 1;
+		if(newsize > buf->capacity)
+			buf->capacity = newsize;
+		buf->data = realloc(buf->data, buf->capacity);
+	}
+
+	p = (char*)buf->data + buf->size;
+	buf->size = newsize;
+	return p;
+}
+
+static inline void
+util_buffer_trim(struct util_buffer* buf)
+{
+	buf->data = realloc(buf->data, buf->size);
+	buf->capacity = buf->size;
+}
+
+#define util_buffer_append(buf, type, v) do {type __v = (v); memcpy(util_buffer_grow((buf), sizeof(type)), &__v, sizeof(type));} while(0)
+#define util_buffer_top_ptr(buf, type) (type*)((buf)->data + (buf)->size - sizeof(type))
+#define util_buffer_top(buf, type) *util_buffer_top_ptr(buf, type)
+#define util_buffer_pop_ptr(buf, type) (type*)((buf)->data + ((buf)->size -= sizeof(type)))
+#define util_buffer_pop(buf, type) *util_buffer_pop_ptr(buf, type)
+#define util_buffer_contains(buf, type) ((buf)->size >= sizeof(type))
+
+#endif /* U_BUFFER_H */