From 29e1a0c31b3a78a82058226b080f777dd6e3ed70 Mon Sep 17 00:00:00 2001
From: John Jones <jmjatlanta@gmail.com>
Date: Wed, 1 Feb 2017 12:15:56 -0500
Subject: [PATCH] Addition of exchange struct (will be used later)

---
 secio/exchange.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 secio/exchange.c

diff --git a/secio/exchange.c b/secio/exchange.c
new file mode 100644
index 0000000..00fd5bd
--- /dev/null
+++ b/secio/exchange.c
@@ -0,0 +1,107 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "libp2p/secio/exchange.h"
+#include "protobuf.h"
+
+//                                                  epubkey                      signature
+enum WireType secio_exchange_message_fields[] = { WIRETYPE_LENGTH_DELIMITED, WIRETYPE_LENGTH_DELIMITED };
+
+
+struct Exchange* libp2p_secio_exchange_new() {
+	struct Exchange* retVal = (struct Exchange*)malloc(sizeof(struct Exchange));
+	if (retVal == NULL)
+		return NULL;
+	memset((void*)retVal, 0, sizeof(struct Exchange));
+	return retVal;
+}
+
+void libp2p_secio_exchange_free( struct Exchange* in) {
+	if (in != NULL) {
+		if (in->epubkey != NULL)
+			free(in->epubkey);
+		if (in->signature != NULL)
+			free(in->signature);
+		free(in);
+	}
+}
+
+/**
+ * retrieves the approximate size of an encoded version of the passed in struct
+ * @param in the struct to look at
+ * @reutrns the size of buffer needed
+ */
+size_t libp2p_secio_exchange_protobuf_encode_size(struct Exchange* in) {
+	size_t retVal = 0;
+	retVal += 11 + in->epubkey_size;
+	retVal += 11 + in->signature_size;
+	return retVal;
+}
+
+/**
+ * Encode the struct Exchange in protobuf format
+ * @param in the struct to be encoded
+ * @param buffer where to put the results
+ * @param max_buffer_length the max to write
+ * @param bytes_written how many bytes were written to the buffer
+ * @returns true(1) on success, otherwise false(0)
+ */
+int libp2p_secio_exchange_protobuf_encode(struct Exchange* in, unsigned char* buffer, size_t max_buffer_length, size_t* bytes_written) {
+	*bytes_written = 0;
+	size_t bytes_used;
+	// epubkey
+	if (!protobuf_encode_length_delimited(1, secio_exchange_message_fields[0], (char*)in->epubkey, in->epubkey_size, &buffer[*bytes_written], max_buffer_length - *bytes_written, &bytes_used))
+		return 0;
+	*bytes_written += bytes_used;
+	// signature
+	if (!protobuf_encode_length_delimited(2, secio_exchange_message_fields[1], (char*)in->signature, in->signature_size, &buffer[*bytes_written], max_buffer_length - *bytes_written, &bytes_used))
+		return 0;
+	*bytes_written += bytes_used;
+	return 1;
+}
+
+/**
+ * Turns a protobuf array into an Exchange struct
+ * @param buffer the protobuf array
+ * @param buffer_length the length of the buffer
+ * @param out a pointer to the new struct Exchange NOTE: this method allocates memory
+ * @returns true(1) on success, otherwise false(0)
+ */
+int libp2p_secio_exchange_protobuf_decode(unsigned char* buffer, size_t buffer_length, struct Exchange** out) {
+	size_t pos = 0;
+	int retVal = 0;
+
+	if (libp2p_secio_exchange_new(out) == 0)
+		goto exit;
+
+	while(pos < buffer_length) {
+		size_t bytes_read = 0;
+		int field_no;
+		enum WireType field_type;
+		if (protobuf_decode_field_and_type(&buffer[pos], buffer_length, &field_no, &field_type, &bytes_read) == 0) {
+			goto exit;
+		}
+		pos += bytes_read;
+		switch(field_no) {
+			case (1): // epubkey
+				if (protobuf_decode_length_delimited(&buffer[pos], buffer_length - pos, (char**)&((*out)->epubkey), &((*out)->epubkey_size), &bytes_read) == 0)
+					goto exit;
+				pos += bytes_read;
+				break;
+			case (2): // signature
+				if (protobuf_decode_length_delimited(&buffer[pos], buffer_length - pos, (char**)&((*out)->signature), &((*out)->signature_size), &bytes_read) == 0)
+					goto exit;
+				pos += bytes_read;
+				break;
+		}
+	}
+
+	retVal = 1;
+
+exit:
+	if (retVal == 0) {
+		libp2p_secio_exchange_free(*out);
+	}
+
+	return retVal;
+}