cobsr.h: add documentation

cobsr.h

@@ -67,8 +67,33 @@ typedef struct
 extern "C" {
 #endif
 
-cobsr_encode_result cobsr_encode(uint8_t *dst_buf_ptr, size_t dst_buf_len, const uint8_t * src_ptr, size_t src_len);
-cobsr_decode_result cobsr_decode(uint8_t *dst_buf_ptr, size_t dst_buf_len, const uint8_t * src_ptr, size_t src_len);
+/* COBS/R-encode a string of input bytes, which may save one byte of output.
+ *
+ * dst_buf_ptr:    The buffer into which the result will be written
+ * dst_buf_len:    Length of the buffer into which the result will be written
+ * src_ptr:        The byte string to be encoded
+ * src_len         Length of the byte string to be encoded
+ *
+ * returns:        A struct containing the success status of the encoding
+ *                 operation and the length of the result (that was written to
+ *                 dst_buf_ptr)
+ */
+cobsr_encode_result cobsr_encode(uint8_t *dst_buf_ptr, size_t dst_buf_len,
+                                 const uint8_t * src_ptr, size_t src_len);
+
+/* Decode a COBS/R byte string.
+ *
+ * dst_buf_ptr:    The buffer into which the result will be written
+ * dst_buf_len:    Length of the buffer into which the result will be written
+ * src_ptr:        The byte string to be decoded
+ * src_len         Length of the byte string to be decoded
+ *
+ * returns:        A struct containing the success status of the decoding
+ *                 operation and the length of the result (that was written to
+ *                 dst_buf_ptr)
+ */
+cobsr_decode_result cobsr_decode(uint8_t *dst_buf_ptr, size_t dst_buf_len,
+                                 const uint8_t * src_ptr, size_t src_len);
 
 
 #ifdef __cplusplus