Changeset: b2cb230ecebf for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=b2cb230ecebf
Modified Files:
gdk/gdk_select.c
Branch: Mar2018
Log Message:
Updated some comments.
diffs (95 lines):
diff --git a/gdk/gdk_select.c b/gdk/gdk_select.c
--- a/gdk/gdk_select.c
+++ b/gdk/gdk_select.c
@@ -38,13 +38,13 @@ virtualize(BAT *bn)
(((bn->ttype == TYPE_void && !is_oid_nil(bn->tseqbase)) ||
bn->ttype == TYPE_oid) &&
bn->tkey && bn->tsorted));
- /* since bn has unique and strictly ascending tail values, we
- * can easily check whether the tail is dense */
+ /* since bn has unique and strictly ascending values, we can
+ * easily check whether the column is dense */
if (bn && bn->ttype == TYPE_oid &&
(BATcount(bn) <= 1 ||
* (const oid *) Tloc(bn, 0) + BATcount(bn) - 1 ==
* (const oid *) Tloc(bn, BUNlast(bn) - 1))) {
- /* tail is dense, replace by virtual oid */
+ /* column is dense, replace by virtual oid */
ALGODEBUG fprintf(stderr,
"#virtualize(bn=%s#"BUNFMT",seq="OIDFMT")\n",
BATgetId(bn), BATcount(bn),
BATcount(bn) > 0 ? * (const oid *) Tloc(bn,
0) : 0);
@@ -1000,24 +1000,24 @@ BAT_scanselect(BAT *b, BAT *s, BAT *bn,
/* generic range select
*
- * Return a dense-headed BAT with the OID values of b in the tail for
- * qualifying tuples. The return BAT is sorted on the tail value
- * (i.e. in the same order as the input BAT).
+ * Return a BAT with the OID values of b for qualifying tuples. The
+ * return BAT is sorted (i.e. in the same order as the input BAT).
*
- * If s[dense,OID] is specified, its tail column is a list of
- * candidates. s should be sorted on the tail value.
+ * If s is non-NULL, it is a list of candidates. s must be sorted.
*
* tl may not be NULL, li, hi, and anti must be either 0 or 1.
*
* If th is NULL, hi is ignored.
*
- * If anti is 0, qualifying tuples are those whose tail value is
- * between tl and th. If li or hi is 1, the respective boundary is
- * inclusive, otherwise exclusive. If th is NULL it is taken to be
- * equal to tl, turning this into an equi- or point-select. Note that
- * for a point select to return anything, li (and hi if th was not
- * NULL) must be 1. There is a special case if tl is nil and th is
- * NULL. This is the only way to select for nil values.
+ * If anti is 0, qualifying tuples are those whose value is between tl
+ * and th (as in x >[=] tl && x <[=] th, where equality depends on li
+ * and hi--so if tl > th, nothing will be returned). If li or hi is
+ * 1, the respective boundary is inclusive, otherwise exclusive. If
+ * th is NULL it is taken to be equal to tl, turning this into an
+ * equi- or point-select. Note that for a point select to return
+ * anything, li (and hi if th was not NULL) must be 1. There is a
+ * special case if tl is nil and th is NULL. This is the only way to
+ * select for nil values.
*
* If anti is 1, the result is the complement of what the result would
* be if anti were 0, except that nils are filtered out.
@@ -1562,8 +1562,8 @@ BATselect(BAT *b, BAT *s, const void *tl
if (s) {
/* restrict first, last so
* that they refer to existing
- * head values of b whose tail
- * is not nil */
+ * head values of b whose
+ * value is not nil */
oid o = (oid) first + b->hseqbase;
BUN last;
first = SORTfndfirst(s, &o);
@@ -1586,8 +1586,8 @@ BATselect(BAT *b, BAT *s, const void *tl
if (s) {
/* restrict first, last so
* that they refer to existing
- * head values of b whose tail
- * is not nil */
+ * head values of b whose
+ * value is not nil */
oid o = (oid) last + b->hseqbase;
BUN first;
last = SORTfndfirst(s, &o);
@@ -1825,12 +1825,10 @@ BATselect(BAT *b, BAT *s, const void *tl
/* theta select
*
- * Returns a dense-headed BAT with the OID values of b in the tail for
- * qualifying tuples. The return BAT is sorted on the tail value
- * (i.e. in the same order as the input BAT).
+ * Returns a BAT with the OID values of b for qualifying tuples. The
+ * return BAT is sorted (i.e. in the same order as the input BAT).
*
- * If s[dense,OID] is specified, its tail column is a list of
- * candidates. s should be sorted on the tail value.
+ * If s is not NULL, it is a list of candidates. s must be sorted.
*
* Theta select returns all values from b which are less/greater than
* or (not) equal to the provided value depending on the value of op.
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