From 21e8dbfd9d11a461ed7f91b495fa39d8a9131b28 Mon Sep 17 00:00:00 2001 From: Alin Mr Date: Wed, 28 Jul 2021 11:40:01 +0300 Subject: ash.c: speedup ${s:} substring (no quotes) This trivial patch makes ${s:...} at least as fast as ${s#??..} in simple tests. It's probably faster for longer substrings, but then one wouldn't use ${s#"1024???s"} anyway - one would switch away from sh. function old new delta subevalvar 1457 1503 +46 Signed-off-by: Alin Mr Signed-off-by: Denys Vlasenko --- shell/ash.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/shell/ash.c b/shell/ash.c index 7b85981ec..e8ec0b1a6 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -7185,14 +7185,19 @@ subevalvar(char *start, char *str, int strloc, if ((unsigned)len > (orig_len - pos)) len = orig_len - pos; - for (vstr = startp; pos; vstr++, pos--) { - if (quotes && (unsigned char)*vstr == CTLESC) + if (!quotes) { + loc = mempcpy(startp, startp + pos, len); + } else { + for (vstr = startp; pos != 0; pos--) { + if ((unsigned char)*vstr == CTLESC) + vstr++; vstr++; - } - for (loc = startp; len; len--) { - if (quotes && (unsigned char)*vstr == CTLESC) + } + for (loc = startp; len != 0; len--) { + if ((unsigned char)*vstr == CTLESC) + *loc++ = *vstr++; *loc++ = *vstr++; - *loc++ = *vstr++; + } } *loc = '\0'; goto out; -- cgit v1.2.3