C: Added a function to get a nucleotide at a specific index in an

encoded sequence

src/encode.h

@@ -108,6 +108,24 @@ bool only_IUPAC_DNA(const char* seq);
 bool is_a_DNA_seq(const char* seq);
 
 
+/**
+ * @brief Returns a nucleotide from a DNA sequence encoded
+ *        with each nucleotide on 2 or 4 bits.
+ *
+ * @param seq The encoded sequence.
+ * @param idx The index (in the decoded sequence) of the nucleotide to get.
+ * @param encoding An integer indicating whether the sequence is encoded with each nucleotide on 2 or 4 bits.
+ *
+ * @returns The (still encoded) nucleotide at the given index.
+ * @retval 255 if an error occurred.
+ *
+ * @see decode_seq_on_2_bits() and decode_seq_on_4_bits()
+ * @since January 2019
+ * @author Celine Mercier (celine.mercier@metabarcoding.org)
+ */
+byte_t get_nucleotide_from_encoded_seq(byte_t* seq, int32_t idx, uint8_t encoding);
+
+
 /**
  * @brief Encodes a DNA sequence with each nucleotide coded on 2 bits.
  *