Add an encoder optimized for in-memory buffers.

git-svn-id: https://svn.kapsi.fi/jpa/nanopb-dev@1088 e3a754e5-d11d-0410-8d38-ebb782a927b9

pb_encode_buffer.h

@@ -0,0 +1,43 @@
+#ifndef _PB_ENCODE_BUFFER_H_
+#define _PB_ENCODE_BUFFER_H_
+
+/* pb_encode_buffer.h: Functions to encode protocol buffers to an
+ * in-memory array of bytes. Depends on pb_encode_buffer.c. The main
+ * function is pb_encode_buffer.  You also need an output buffer,
+ * structures and their field descriptions (just like with pb_decode
+ * or pb_encode).
+ */
+
+#include <stdbool.h>
+#include "pb.h"
+
+/* Output stream for an in-memory buffer.
+ */
+struct _pb_strstream_t
+{
+    uint8_t *buffer;
+    uint8_t *last;
+};
+
+pb_strstream_t pb_strstream_from_buffer(uint8_t *buf, size_t bufsize);
+bool pb_buf_write(pb_strstream_t *stream, const uint8_t *buf, size_t count);
+
+/* --- Helper functions ---
+ * You may want to use these from your caller or callbacks.
+ */
+
+bool pb_encbuf_varint(pb_strstream_t *stream, uint64_t value);
+bool pb_encbuf_tag(pb_strstream_t *stream, pb_wire_type_t wiretype, int field_number);
+/* Encode tag based on LTYPE and field number defined in the field structure. */
+bool pb_encbuf_tag_for_field(pb_strstream_t *stream, const pb_field_t *field);
+/* Write length as varint and then the contents of buffer. */
+bool pb_encbuf_string(pb_strstream_t *stream, const uint8_t *buffer, size_t size);
+
+/* Encode struct to given output stream.
+ * Returns true on success, false on any failure.
+ * The actual struct pointed to by src_struct must match the description in msg.
+ * All required fields in the struct are assumed to have been filled in.
+ */
+bool pb_encode_buffer(pb_strstream_t *stream, const pb_message_t *msg, const void *src_struct);
+
+#endif