Re: av.c patch (having slight problems)

Message-ID: <LAW2-F113pL32ctFfj800000d81@hotmail.com>

unshift() speedup.

p4raw-id: //depot/perl@7825

diff --git a/av.c b/av.c
index 777651d..e5f6dc8 100644 (file)
--- a/av.c
+++ b/av.c
@@ -554,6 +554,7 @@ Perl_av_unshift(pTHX_ register AV *av, register I32 num)
     register I32 i;
     register SV **ary;
     MAGIC* mg;
+    I32 slide;
 
     if (!av || num <= 0)
        return;
@@ -591,6 +592,9 @@ Perl_av_unshift(pTHX_ register AV *av, register I32 num)
     }
     if (num) {
        i = AvFILLp(av);
+       /* Create extra elements */
+       slide = i > 0 ? i : 0;
+       num += slide;
        av_extend(av, i + num);
        AvFILLp(av) += num;
        ary = AvARRAY(av);
@@ -598,6 +602,10 @@ Perl_av_unshift(pTHX_ register AV *av, register I32 num)
        do {
            ary[--num] = &PL_sv_undef;
        } while (num);
+       /* Make extra elements into a buffer */
+       AvMAX(av) -= slide;
+       AvFILLp(av) -= slide;
+       SvPVX(av) = (char*)(AvARRAY(av) + slide);
     }
 }