+/****d* silcutil/SilcBufferFormatAPI/SILC_STR_REPLACE
+ *
+ * NAME
+ *
+ * #define SILC_STR_REPLACE(unsigned char *data, SilcUInt32 len) ...
+ *
+ * DESCRIPTION
+ *
+ * Encode the `data' of length of `len' bytes into the buffer, replacing
+ * existing data.
+ *
+ * If the length of the current data area is equal to `len' the data area
+ * is replaced with `data'.
+ *
+ * If `len' is longer than the data area, it will be enlarged to fit the
+ * `data'. If there is data in the tail area, it will not be replaced,
+ * but the buffer is enlarged and the old tail area will be copied to the
+ * new tail area, thus preserving any data in the buffer (the data is
+ * in effect appended to the current data area).
+ *
+ * If `len' is shorter than than the data area, only the bytes in `data'
+ * are replaced, and rest are deleted from the data area. The buffer size
+ * is also reduced but no other data is lost in the process.
+ *
+ * If `len' is 0 but `data' is non-NULL, this will delete all bytes from
+ * the current data area. If `data' is NULL this macro has no effect to
+ * the buffer.
+ *
+ * Use this only for formatting.
+ *
+ * Formatting: SILC_STR_REPLACE(unsigned char *, SilcUInt32)
+ *
+ * Example:
+ *
+ * Before replacing
+ * -------------------------
+ * | head | 12345 | 67890 |
+ * -------------------------
+ *
+ * After replacing with 12345XXX (appends)
+ * ----------------------------
+ * | head | 12345XXX | 67890 |
+ * ----------------------------
+ *
+ * After replacing with YYY (deletes)
+ * -----------------------
+ * | head | YYY | 67890 |
+ * -----------------------
+ *
+ ***/
+#define SILC_STR_REPLACE(x, l) SILC_PARAM_UICHAR | SILC_PARAM_REPLACE, (x), (l)
+