-bool pb_read(pb_istream_t *stream, uint8_t *buf, size_t count);
-
-/* Structure for defining custom input streams. You will need to provide
- * a callback function to read the bytes from your storage, which can be
- * for example a file or a network socket.
- *
- * The callback must conform to these rules:
- *
- * 1) Return false on IO errors. This will cause decoding to abort.
- * 2) You can use state to store your own data (e.g. buffer pointer),
- * and rely on pb_read to verify that no-body reads past bytes_left.
- * 3) Your callback may be used with substreams, in which case bytes_left
- * is different than from the main stream. Don't use bytes_left to compute
- * any pointers.
- */
-struct _pb_istream_t
-{
-#ifdef PB_BUFFER_ONLY
- /* Callback pointer is not used in buffer-only configuration.
- * Having an int pointer here allows binary compatibility but
- * gives an error if someone tries to assign callback function.
- */
- int *callback;
-#else
- bool (*callback)(pb_istream_t *stream, uint8_t *buf, size_t count);
-#endif
-
- void *state; /* Free field for use by callback implementation */
- size_t bytes_left;
-
-#ifndef PB_NO_ERRMSG
- const char *errmsg;
-#endif
-};