Extend inline / fixed length bytes array support (issue #244)

Adds support for proto3 and POINTER field types to have
fixed length bytes arrays. Also changed the .proto option
to a separate fixed_length:true, while also supporting the old FT_INLINE
option.

Restructured the generator and decoder logic to threat the inline
bytes fields more like "just another field type".

1 files changed, 25 insertions, 7 deletions

diff --git a/pb_decode.c b/pb_decode.c
index 92d0175d..a8cd61a7 100644
--- a/pb_decode.c
+++ b/pb_decode.c
@@ -42,6 +42,7 @@ static bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *f
 static bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
 static bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest);
 static bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest);
+static bool checkreturn pb_dec_fixed_length_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
 static bool checkreturn pb_skip_varint(pb_istream_t *stream);
 static bool checkreturn pb_skip_string(pb_istream_t *stream);
 
@@ -65,7 +66,7 @@ static const pb_decoder_t PB_DECODERS[PB_LTYPES_COUNT] = {
     &pb_dec_string,
     &pb_dec_submessage,
     NULL, /* extensions */
-    &pb_dec_bytes /* PB_LTYPE_FIXED_LENGTH_BYTES */
+    &pb_dec_fixed_length_bytes
 };
 
 /*******************************
@@ -1286,12 +1287,6 @@ static bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *fie
     }
     else
     {
-        if (PB_LTYPE(field->type) == PB_LTYPE_FIXED_LENGTH_BYTES) {
-            if (size != field->data_size)
-                PB_RETURN_ERROR(stream, "incorrect inline bytes size");
-            return pb_read(stream, (pb_byte_t*)dest, field->data_size);
-        }
-
         if (alloc_size > field->data_size)
             PB_RETURN_ERROR(stream, "bytes overflow");
         bdest = (pb_bytes_array_t*)dest;
@@ -1359,3 +1354,26 @@ static bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t
         return false;
     return status;
 }
+
+static bool checkreturn pb_dec_fixed_length_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest)
+{
+    uint32_t size;
+
+    if (!pb_decode_varint32(stream, &size))
+        return false;
+
+    if (size > PB_SIZE_MAX)
+        PB_RETURN_ERROR(stream, "bytes overflow");
+
+    if (size == 0)
+    {
+        /* As a special case, treat empty bytes string as all zeros for fixed_length_bytes. */
+        memset(dest, 0, field->data_size);
+        return true;
+    }
+
+    if (size != field->data_size)
+        PB_RETURN_ERROR(stream, "incorrect fixed length bytes size");
+
+    return pb_read(stream, (pb_byte_t*)dest, field->data_size);
+}