Encoder

git-svn-id: https://svn.kapsi.fi/jpa/nanopb@951 e3a754e5-d11d-0410-8d38-ebb782a927b9

1 files changed, 22 insertions, 14 deletions

diff --git a/pb_decode.h b/pb_decode.h
index 448b55d..011efdd 100644
--- a/pb_decode.h
+++ b/pb_decode.h
@@ -1,18 +1,32 @@
 #ifndef _PB_DECODE_H_
 #define _PB_DECODE_H_
 
+/* pb_decode.h: Functions to decode protocol buffers. Depends on pb_decode.c.
+ * The main function is pb_decode. You will also need to create an input
+ * stream, which is easiest to do with pb_istream_t.
+ * 
+ * You also need structures and their corresponding pb_field_t descriptions.
+ * These are usually generated from .proto-files with a script.
+ */
+
 #include <stdbool.h>
 #include "pb.h"
 
 /* Lightweight input stream.
- * If buf is NULL, read but don't store bytes.
- * You can to provide a callback function for reading or use
+ * You can provide a callback function for reading or use
  * pb_istream_from_buffer.
  * 
- * You can use state to store your own data (e.g. buffer pointer),
+ * Rules for callback:
+ * 1) Return false on IO errors. This will cause decoding to abort.
+ * 
+ * 2) If buf is NULL, read but don't store bytes ("skip input").
+ * 
+ * 3) 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.
- * However, substreams may change bytes_left so don't use that to
- * compute any pointers.
+ * 
+ * 4) 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
 {
@@ -25,6 +39,7 @@ pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize);
 bool pb_read(pb_istream_t *stream, uint8_t *buf, size_t count);
 
 /* Decode from stream to destination struct.
+ * Returns true on success, false on any failure.
  * The actual struct pointed to by dest must match the description in fields.
  */
 bool pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct);
@@ -49,15 +64,8 @@ bool pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest);
 bool pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
 bool pb_dec_fixed(pb_istream_t *stream, const pb_field_t *field, void *dest);
 
-bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, uint8_t *dest);
-bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, uint8_t *dest);
+bool pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
+bool pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest);
 bool pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest);
 
-typedef bool (*pb_decoder_t)(pb_istream_t *stream, const pb_field_t *field, void *dest);
-
-/* --- Function pointers to field decoders ---
- * Order in the array must match pb_action_t LTYPE numbering.
- */
-const pb_decoder_t PB_DECODERS[PB_LTYPES_COUNT];
-
 #endif