From: Daniel Shahaf <d.s@daniel.shahaf.name>
To: zsh-workers@zsh.org
Subject: [PATCH 1/2] Optimize indexing array parameters.
Date: Sat, 30 Jul 2016 13:11:50 +0000 [thread overview]
Message-ID: <1469884311-3264-1-git-send-email-danielsh@tarsus.local2> (raw)
% () { 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
---
Src/params.c | 2 +-
Src/subst.c | 15 +++++++++++----
Src/utils.c | 40 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 52 insertions(+), 5 deletions(-)
diff --git a/Src/params.c b/Src/params.c
index e7a7365..33f177e 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -2026,7 +2026,7 @@ getstrvalue(Value v)
else {
if (v->start < 0)
v->start += arrlen(ss);
- s = (v->start >= arrlen(ss) || v->start < 0) ?
+ s = (arrlen_le(ss, v->start) || v->start < 0) ?
(char *) hcalloc(1) : ss[v->start];
}
return s;
diff --git a/Src/subst.c b/Src/subst.c
index 8e704b1..e3af156 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -2548,12 +2548,19 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags,
* necessary joining of arrays until this point
* to avoid the multsub() horror.
*/
- int tmplen = arrlen(v->pm->gsu.a->getfn(v->pm));
- if (v->start < 0)
+ /* arrlen() is expensive, so only compute it if needed. */
+ int tmplen = -1;
+
+ if (v->start < 0) {
+ tmplen = arrlen(v->pm->gsu.a->getfn(v->pm));
v->start += tmplen + ((v->flags & VALFLAG_INV) ? 1 : 0);
- if (!(v->flags & VALFLAG_INV) &&
- (v->start >= tmplen || v->start < 0))
+ }
+ if (!(v->flags & VALFLAG_INV))
+ if (v->start < 0 ||
+ (tmplen != -1
+ ? v->start >= tmplen
+ : arrlen_le(v->pm->gsu.a->getfn(v->pm), v->start)))
vunset = 1;
}
if (!vunset) {
diff --git a/Src/utils.c b/Src/utils.c
index 95be1fb..95da960 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. */
/**/
next reply other threads:[~2016-07-30 13:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-30 13:11 Daniel Shahaf [this message]
2016-07-30 13:11 ` [PATCH 2/2] Start using the new arrlen_ge() / arrlen_le() helpers Daniel Shahaf
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