38973: Optimize indexing array parameters.

% () { for 1 in $prefix/zsh/bin/zsh Src/zsh; do $1 -f -c 'a=( {1..1000000} ); repeat 3 time ( repeat 300 : $a[1]  )'; done }
( repeat 300; do; : $a[1]; done; )  1.68s user 0.01s system 98% cpu 1.718 total
( repeat 300; do; : $a[1]; done; )  1.69s user 0.01s system 99% cpu 1.710 total
( repeat 300; do; : $a[1]; done; )  1.69s user 0.01s system 99% cpu 1.714 total

( repeat 300; do; : $a[1]; done; )  0.00s user 0.01s system 72% cpu 0.022 total
( repeat 300; do; : $a[1]; done; )  0.00s user 0.01s system 72% cpu 0.022 total
( repeat 300; do; : $a[1]; done; )  0.01s user 0.01s system 69% cpu 0.023 total

1 files changed, 40 insertions, 0 deletions

diff --git a/Src/utils.c b/Src/utils.c
index 95be1fb98..95da96058 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -2280,6 +2280,46 @@ arrlen(char **s)
     return count;
 }
 
+/* Return TRUE iff arrlen(s) >= lower_bound, but more efficiently. */
+
+/**/
+mod_export char
+arrlen_ge(char **s, unsigned lower_bound)
+{
+    while (lower_bound--)
+	if (!*s++)
+	    return 0 /* FALSE */;
+
+    return 1 /* TRUE */;
+}
+
+/* Return TRUE iff arrlen(s) > lower_bound, but more efficiently. */
+
+/**/
+mod_export char
+arrlen_gt(char **s, unsigned lower_bound)
+{
+    return arrlen_ge(s, 1+lower_bound);
+}
+
+/* Return TRUE iff arrlen(s) <= upper_bound, but more efficiently. */
+
+/**/
+mod_export char
+arrlen_le(char **s, unsigned upper_bound)
+{
+    return arrlen_lt(s, 1+upper_bound);
+}
+
+/* Return TRUE iff arrlen(s) < upper_bound, but more efficiently. */
+
+/**/
+mod_export char
+arrlen_lt(char **s, unsigned upper_bound)
+{
+    return !arrlen_ge(s, upper_bound);
+}
+
 /* Skip over a balanced pair of parenthesis. */
 
 /**/