RRTimeslice: Added rrtimeslice_cmp().

[postrr.git] / src / rrtimeslice.c

diff --git a/src/rrtimeslice.c b/src/rrtimeslice.c
index 25e9cb38c1ce2caf73eb3b7e5d5e476e4d4eda3b..7de9ed742244b8c30b7ec2e7266e3fb9ae3ed552 100644 (file)
--- a/src/rrtimeslice.c
+++ b/src/rrtimeslice.c
@@ -195,6 +195,43 @@ rrtimeslice_apply_typmod(rrtimeslice_t *tslice, int32 typmod)
        return 0;
 } /* rrtimeslice_apply_typmod */
 
+/*
+ * rrtimeslice_cmp_unify:
+ * Unify two RRTimeslices in order to prepare them for comparison. That is, if
+ * either one of the arguments does not have any typmod applied, then apply
+ * the typmod of the other argument. Throws an error if the typmods don't
+ * match.
+ *
+ * Returns:
+ *  - 0 if the arguments could be unified
+ *  - 1 if only the first argument is NULL
+ *  - 2 if both arguments are NULL
+ *  - 3 if only the second argument is NULL
+ */
+static int
+rrtimeslice_cmp_unify(rrtimeslice_t *ts1, rrtimeslice_t *ts2)
+{
+       if ((! ts1) && (! ts2))
+               return 0;
+       else if (! ts1)
+               return -1;
+       else if (! ts2)
+               return 1;
+
+       if (ts1->tsid && (! ts2->tsid))
+               rrtimeslice_apply_typmod(ts2, ts1->tsid);
+       else if ((! ts1->tsid) && ts2->tsid)
+               rrtimeslice_apply_typmod(ts1, ts2->tsid);
+
+       if (ts1->tsid != ts2->tsid) /* XXX: compare len/num */
+               ereport(ERROR, (
+                                       errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+                                       errmsg("invalid comparison: cannot compare "
+                                               "rrtimeslices with different typmods (yet)")
+                               ));
+       return 0;
+} /* rrtimeslice_cmp_unify */
+
 /*
  * prototypes for PostgreSQL functions
  */
@@ -209,6 +246,8 @@ PG_FUNCTION_INFO_V1(rrtimeslice_typmodout);
 PG_FUNCTION_INFO_V1(rrtimeslice_to_rrtimeslice);
 PG_FUNCTION_INFO_V1(rrtimeslice_to_timestamptz);
 
+PG_FUNCTION_INFO_V1(rrtimeslice_cmp);
+
 PG_FUNCTION_INFO_V1(rrtimeslice_seq_eq);
 PG_FUNCTION_INFO_V1(rrtimeslice_seq_ne);
 PG_FUNCTION_INFO_V1(rrtimeslice_seq_lt);
@@ -490,26 +529,43 @@ rrtimeslice_to_timestamptz(PG_FUNCTION_ARGS)
 } /* rrtimeslice_to_timestamptz */
 
 int
-rrtimeslice_seq_cmp_internal(rrtimeslice_t *ts1, rrtimeslice_t *ts2)
+rrtimeslice_cmp_internal(rrtimeslice_t *ts1, rrtimeslice_t *ts2)
 {
-       if ((! ts1) && (! ts2))
+       int status;
+
+       status = rrtimeslice_cmp_unify(ts1, ts2);
+       if (status) /* [1, 3] -> [-1, 1] */
+               return status - 2;
+
+       if (ts1->tstamp == ts2->tstamp)
                return 0;
-       else if (! ts1)
+       else if ((ts1->seq == ts2->seq) && (ts1->tstamp < ts2->tstamp))
                return -1;
-       else if (! ts2)
+       else if (ts1->tstamp < ts2->tstamp)
+               return -2;
+       else if ((ts1->seq == ts2->seq) && (ts1->tstamp > ts2->tstamp))
                return 1;
+       else
+               return 2;
+} /* rrtimeslice_cmp_internal */
 
-       if (ts1->tsid && (! ts2->tsid))
-               rrtimeslice_apply_typmod(ts2, ts1->tsid);
-       else if ((! ts1->tsid) && ts2->tsid)
-               rrtimeslice_apply_typmod(ts1, ts2->tsid);
+Datum
+rrtimeslice_cmp(PG_FUNCTION_ARGS)
+{
+       rrtimeslice_t *ts1 = PG_GETARG_RRTIMESLICE_P(0);
+       rrtimeslice_t *ts2 = PG_GETARG_RRTIMESLICE_P(1);
 
-       if (ts1->tsid != ts2->tsid) /* XXX: compare len/num */
-               ereport(ERROR, (
-                                       errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-                                       errmsg("invalid comparison: cannot compare "
-                                               "rrtimeslices with different typmods (yet)")
-                               ));
+       PG_RETURN_INT32(rrtimeslice_cmp_internal(ts1, ts2));
+} /* rrtimeslice_cmp */
+
+int
+rrtimeslice_seq_cmp_internal(rrtimeslice_t *ts1, rrtimeslice_t *ts2)
+{
+       int status;
+
+       status = rrtimeslice_cmp_unify(ts1, ts2);
+       if (status) /* [1, 3] -> [-1, 1] */
+               return status - 2;
 
        if (ts1->seq < ts2->seq)
                return -1;
@@ -580,7 +636,7 @@ rrtimeslice_seq_cmp(PG_FUNCTION_ARGS)
        rrtimeslice_t *ts2 = PG_GETARG_RRTIMESLICE_P(1);
 
        PG_RETURN_INT32(rrtimeslice_seq_cmp_internal(ts1, ts2));
-} /* rrtimeslice_seq_ge */
+} /* rrtimeslice_seq_cmp */
 
 Datum
 rrtimeslice_seq_hash(PG_FUNCTION_ARGS)