1 files changed, 52 insertions, 0 deletions
diff --git a/lib/i2ctcp/i2ctcpv1.c b/lib/i2ctcp/i2ctcpv1.c
new file mode 100644
index 0000000..944df3a
--- /dev/null
+++ b/lib/i2ctcp/i2ctcpv1.c
@@ -0,0 +1,52 @@
+#include <mpack.h>
+#ifndef MIN
+#define MIN(a,b) (((a) < (b)) ? (a) : (b))
+#endif
+
+#include "i2ctcpv1.h"
+
+int i2ctcp_read(i2ctcp_msg_t * target, const char * buf, size_t buf_sz) {
+	mpack_reader_t reader;
+	mpack_reader_init_data(&reader, buf, buf_sz);
+
+	// at start of message
+	if (target->_rdata == 0) {
+		target->addr = mpack_expect_u16(&reader);
+		target->length = target->_rdata = mpack_expect_bin(&reader);
+		if (mpack_reader_error(&reader) != mpack_ok) return -1;
+		target->data = (char *) malloc(target->length);
+
+		// seek forward in buf to where binary data begins (to avoid having to read
+		// from private member reader.data in the memcpy below)
+		buf += buf_sz - mpack_reader_remaining(&reader, NULL);
+	}
+
+	// continue reading chunks of target->data until the amount of bytes
+	// specified in target->length
+	size_t to_read = MIN(mpack_reader_remaining(&reader, NULL), target->_rdata);
+	char * data = target->data + target->length - target->_rdata;
+	memcpy(data, buf, to_read);
+	target->_rdata -= to_read;
+	// NOTE: memcpy is used here because mpack_read_bytes requires that a tag was
+	// opened, which is not the case for the chunks following the initial mpack
+	// header
+
+	// if rdata = 0, the message was completely read
+	return target->_rdata;
+}
+
+void i2ctcp_read_reset(i2ctcp_msg_t * target) {
+	target->_rdata = 0;
+}
+
+bool i2ctcp_write(const i2ctcp_msg_t * target, char ** buf, size_t * buf_sz) {
+	mpack_writer_t writer;
+	mpack_writer_init_growable(&writer, buf, buf_sz);
+
+	mpack_write_u16(&writer, target->addr);
+	mpack_write_bin(&writer, target->data, target->length);
+
+	// finish writing
+	return mpack_writer_destroy(&writer) == mpack_ok;
+}
+