Re: Using existing memory for an SV's PV

	Message-ID: <373318ae.19292461@smtp1.ibm.net>

p4raw-id: //depot/perl@3375

diff --git a/sv.c b/sv.c
index 5772954..463359e 100644 (file)
--- a/sv.c
+++ b/sv.c
@@ -2061,7 +2061,8 @@ sv_setsv(SV *dstr, register SV *sstr)
            }
            if (SvPVX(dstr)) {
                (void)SvOOK_off(dstr);          /* backoff */
-               Safefree(SvPVX(dstr));
+               if (SvLEN(dstr))
+                   Safefree(SvPVX(dstr));
                SvLEN(dstr)=SvCUR(dstr)=0;
            }
        }
@@ -2098,7 +2099,7 @@ sv_setsv(SV *dstr, register SV *sstr)
                    SvFLAGS(dstr) &= ~SVf_OOK;
                    Safefree(SvPVX(dstr) - SvIVX(dstr));
                }
-               else
+               else if (SvLEN(dstr))
                    Safefree(SvPVX(dstr));
            }
            (void)SvPOK_only(dstr);
@@ -2227,7 +2228,7 @@ sv_usepvn(register SV *sv, register char *ptr, register STRLEN len)
        return;
     }
     (void)SvOOK_off(sv);
-    if (SvPVX(sv))
+    if (SvPVX(sv) && SvLEN(sv))
        Safefree(SvPVX(sv));
     Renew(ptr, len+1, char);
     SvPVX(sv) = ptr;
@@ -2273,6 +2274,13 @@ sv_chop(register SV *sv, register char *ptr)     /* like set but assuming ptr is in
        sv_upgrade(sv,SVt_PVIV);
 
     if (!SvOOK(sv)) {
+       if (!SvLEN(sv)) { /* make copy of shared string */
+           char *pvx = SvPVX(sv);
+           STRLEN len = SvCUR(sv);
+           SvGROW(sv, len + 1);
+           Move(pvx,SvPVX(sv),len,char);
+           *SvEND(sv) = '\0';
+       }
        SvIVX(sv) = 0;
        SvFLAGS(sv) |= SVf_OOK;
     }