--- /dev/null
+/*
+** Data structures for message tables, used for parsing and serialization.
+** This are much lighter-weight than full reflection, but they are do not
+** have enough information to convert to text format, JSON, etc.
+**
+** The definitions in this file are internal to upb.
+**/
+
+#ifndef UPB_MSG_H_
+#define UPB_MSG_H_
+
+#include <stdint.h>
+#include <string.h>
+#include "upb/upb.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef void upb_msg;
+
+/** upb_msglayout *************************************************************/
+
+/* upb_msglayout represents the memory layout of a given upb_msgdef. The
+ * members are public so generated code can initialize them, but users MUST NOT
+ * read or write any of its members. */
+
+typedef struct {
+ uint32_t number;
+ uint16_t offset;
+ int16_t presence; /* If >0, hasbit_index+1. If <0, oneof_index+1. */
+ uint16_t submsg_index; /* undefined if descriptortype != MESSAGE or GROUP. */
+ uint8_t descriptortype;
+ uint8_t label;
+} upb_msglayout_field;
+
+typedef struct upb_msglayout {
+ const struct upb_msglayout *const* submsgs;
+ const upb_msglayout_field *fields;
+ /* Must be aligned to sizeof(void*). Doesn't include internal members like
+ * unknown fields, extension dict, pointer to msglayout, etc. */
+ uint16_t size;
+ uint16_t field_count;
+ bool extendable;
+} upb_msglayout;
+
+/** Message internal representation *******************************************/
+
+/* Our internal representation for repeated fields. */
+typedef struct {
+ void *data; /* Each element is element_size. */
+ size_t len; /* Measured in elements. */
+ size_t size; /* Measured in elements. */
+} upb_array;
+
+upb_msg *upb_msg_new(const upb_msglayout *l, upb_arena *a);
+upb_msg *upb_msg_new(const upb_msglayout *l, upb_arena *a);
+
+void upb_msg_addunknown(upb_msg *msg, const char *data, size_t len,
+ upb_arena *arena);
+const char *upb_msg_getunknown(const upb_msg *msg, size_t *len);
+
+upb_array *upb_array_new(upb_arena *a);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* UPB_MSG_H_ */