Re-add a simplified upb_msg.

core/upb_msg.h

@@ -0,0 +1,99 @@
+/*
+ * upb - a minimalist implementation of protocol buffers.
+ *
+ * Copyright (c) 2010 Joshua Haberman.  See LICENSE for details.
+ *
+ * Data structure for storing a message of protobuf data.
+ */
+
+#ifndef UPB_MSG_H
+#define UPB_MSG_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+  upb_atomic_refcount_t refcount;
+  uint32_t len;
+  uint32_t size;
+  upb_valueptr elements;
+};
+
+upb_array *upb_array_new(void);
+
+INLINE uint32_t upb_array_len(upb_array *a) {
+  return a->len;
+}
+
+void _upb_array_free(upb_array *a, upb_fielddef *f);
+INLINE void upb_array_unref(upb_array *a, upb_fielddef *f) {
+  if (upb_atomic_unref(&a->refcount)) _upb_array_free(a, f);
+}
+
+INLINE upb_value upb_array_get(upb_array *a, upb_fielddef *f, uint32_t elem) {
+  assert(elem < upb_array_len(a));
+  return upb_value_read(_upb_array_getptr(a, f, elem), f->type);
+}
+
+// For string or submessages, will release a ref on the previously set value.
+INLINE void upb_array_set(upb_array *a, upb_fielddef *f, uint32_t elem,
+                          upb_value val) {
+}
+
+// Append an element with the default value, returning it.  For strings or
+// submessages, this will try to reuse previously allocated memory.
+INLINE upb_value upb_array_append_mutable(upb_array *a, upb_fielddef *f) {
+}
+
+typedef struct {
+  upb_atomic_refcount_t refcount;
+  uint8_t data[4];  // We allocate the appropriate amount per message.
+} upb_msg;
+
+// Creates a new msg of the given type.
+upb_msg *upb_msg_new(upb_msgdef *md);
+
+void _upb_msg_free(upb_msg *msg, upb_msgdef *md);
+INLINE void upb_msg_unref(upb_msg *msg, upb_msgdef *md) {
+  if (upb_atomic_unref(&msg->refcount)) _upb_msg_free(msg, md);
+}
+
+// Tests whether the given field is explicitly set, or whether it will return a
+// default.
+INLINE bool upb_msg_has(upb_msg *msg, upb_fielddef *f) {
+  return (msg->data[f->field_index/8] & (1 << (f->field_index % 8))) != 0;
+}
+
+// Returns the current value of the given field if set, or the default value if
+// not set.
+INLINE upb_value upb_msg_get(upb_msg *msg, upb_fielddef *f) {
+  if (upb_msg_has(msg, f)) {
+    return upb_value_read(_upb_msg_getptr(msg, f), f->type);
+  } else {
+    return f->default_value;
+  }
+}
+
+// If the given string, submessage, or array is already set, returns it.
+// Otherwise sets it and returns an empty instance, attempting to reuse any
+// previously allocated memory.
+INLINE upb_value upb_msg_getmutable(upb_msg *msg, upb_fielddef *f) {
+}
+
+// Sets the current value of the field.  If this is a string, array, or
+// submessage field, releases a ref on the value (if any) that was previously
+// set.
+INLINE void upb_msg_set(upb_msg *msg, upb_fielddef *f, upb_value val) {
+}
+
+// Unsets all field values back to their defaults.
+INLINE void upb_msg_clear(upb_msg *msg, upb_msgdef *md) {
+  memset(msg->data, 0, md->set_flags_bytes);
+}
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif