separate the i2c over tcp from puzzle bus libraries

1 files changed, 71 insertions, 0 deletions

diff --git a/i2ctcp/i2ctcpv1.h b/i2ctcp/i2ctcpv1.h
new file mode 100644
index 0000000..799b668
--- /dev/null
+++ b/i2ctcp/i2ctcpv1.h
@@ -0,0 +1,71 @@
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** \brief I2C over TCP message (v1) */
+struct i2ctcp_msg {
+	uint16_t addr; //!< I^2^C address
+	char * data;   //!< message content
+	size_t length; //!< message size
+	size_t _rdata; //!< \private remaining bytes to read until message is complete
+};
+typedef struct i2ctcp_msg i2ctcp_msg_t;
+
+/**
+ * \brief Read chunk of input stream, and store resulting message in \p target
+ *
+ * This function is called for each chunk of data from an input stream, and
+ * will parse the next puzzle bus message into \p target. The input stream is
+ * assumed to only contain messages encoded by \p i2ctcp_write()
+ *
+ * \param target  pointer to struct that will contain the finished message data
+ * \param buf     pointer to input stream data chunk
+ * \param buf_sz  size of \p buf
+ *
+ * \returns Integer representing amount of bytes required to finish message, or
+ * -1 if the message header could not be read. If this function returns 0, the
+ *  message in \p target is complete.
+ *
+ * \note target->data will automatically be allocated by this function, even if
+ * the message is not fully parsed. This variable must be `free()`d by the
+ * caller after each complete message to prevent memory leaks.
+ */
+int i2ctcp_read(i2ctcp_msg_t * target, const char * buf, size_t buf_sz);
+
+/**
+ * \brief reset the remaining message data counter
+ *
+ * Calling this function has the effect of forcing \c i2ctcp_read() to parse
+ * the next buffer chunk as the start of a new message. This function may be
+ * called before reading a TCP frame's data to mitigate any synchronization
+ * issues arising from earlier corrupt or otherwise malformed messages.
+ */
+void i2ctcp_read_reset(i2ctcp_msg_t * target);
+
+/**
+ * \brief Allocate and write a msgpack-formatted message to \p buf
+ *
+ * This function allocates a buffer large enough to fit the message specified
+ * in \p target, and encodes the data in \p target in a format that can be
+ * decoded later using \p i2ctcp_read()
+ *
+ * \param target  pointer to struct that contains the message data
+ * \param buf     pointer to \c char* that will contain the formatted message
+ * \param buf_sz  pointer to \c size_t that will represent the final size of \p buf
+ *
+ * \returns boolean true if a the message could be encoded successfully, false
+ * if there was some kind of error
+ *
+ * \note the pointer stored in \p buf must be `free()`d by the caller afterwards
+ */
+bool i2ctcp_write(const i2ctcp_msg_t * target, char ** buf, size_t * buf_sz);
+
+#ifdef __cplusplus
+}
+#endif
+