protobuf/core/upb_msg.h

/*
 * upb - a minimalist implementation of protocol buffers.
 *
 * Copyright (c) 2010-2011 Joshua Haberman.  See LICENSE for details.
 *
 * Data structure for storing a message of protobuf data.  Unlike Google's
 * protobuf, upb_msg and upb_array are reference counted instead of having
 * exclusive ownership of their fields.  This is a better match for dynamic
 * languages where statements like a.b = other_b are normal.
 *
 * upb's parsers and serializers could also be used to populate and serialize
 * other kinds of message objects (even one generated by Google's protobuf).
 */

#ifndef UPB_MSG_H
#define UPB_MSG_H

#include "upb.h"
#include "upb_def.h"
#include <stdlib.h>

#ifdef __cplusplus
extern "C" {
#endif

/* upb_array ******************************************************************/

typedef uint32_t upb_arraylen_t;
struct _upb_array {
  upb_atomic_refcount_t refcount;
  upb_arraylen_t len;
  upb_arraylen_t size;
  upb_valueptr elements;
};

void _upb_array_free(upb_array *a, upb_fielddef *f);
INLINE upb_valueptr _upb_array_getptr(upb_array *a, upb_fielddef *f,
                                      uint32_t elem) {
  upb_valueptr p;
  p._void = &a->elements.uint8[elem * upb_types[f->type].size];
  return p;
}

upb_array *upb_array_new(void);

INLINE void upb_array_unref(upb_array *a, upb_fielddef *f) {
  if (upb_atomic_unref(&a->refcount)) _upb_array_free(a, f);
}

INLINE uint32_t upb_array_len(upb_array *a) {
  return a->len;
}

/* upb_msg ********************************************************************/

struct _upb_msg {
  upb_atomic_refcount_t refcount;
  uint8_t data[4];  // We allocate the appropriate amount per message.
};

void _upb_msg_free(upb_msg *msg, upb_msgdef *md);

INLINE upb_valueptr _upb_msg_getptr(upb_msg *msg, upb_fielddef *f) {
  upb_valueptr p;
  p._void = &msg->data[f->byte_offset];
  return p;
}

// Creates a new msg of the given type.
upb_msg *upb_msg_new(upb_msgdef *md);

// Unrefs the given message.
INLINE void upb_msg_unref(upb_msg *msg, upb_msgdef *md) {
  if (msg && 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;
}

// 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);
}

// Registers a set of handlers that will populate this msgdef.
void upb_msg_register_handlers(upb_msg *msg, upb_msgdef *md,
                               upb_handlers *handlers);

#ifdef __cplusplus
}  /* extern "C" */
#endif

#endif