Data::Dumper: refactor XS implementation

There are over a dozen variables that control the details of how Data::Dumper
generates output, almost all of which remain unchanged while dumping a single
set of objects. The previous implementation passed each of those control
variables as a separate argument to the recursive DD_dump() function, which
meant that DD_dump() took over two dozen parameters. This is already far
beyond what seems reasonable, and the problem will only get worse in future
as Data::Dumper acquires more features.

This refactoring therefore extracts most of those style variables into a
struct, and passes it to the recursive calls as a pointer-to-const. This is
clearly of huge benefit for maintainability. In addition, it seems plausible
that it will make dumping slightly faster, especially for deeply-nested data
structures: requiring every recursive call to have its own copy of
them on the stack meant that every call frame would take up more than a
single cache line of stack space even on 32-bit platforms. Putting them all
in a single struct means that this space is used only once per dump instead.

"If you have a procedure with 10 parameters, you probably missed some."
—Alan Perlis, Epigrams on Programming, ACM SIGPLAN Notices 17 (9), September
1982, pp. 7–13. http://pu.inf.uni-tuebingen.de/users/klaeren/epigrams.html

diff --git a/dist/Data-Dumper/Dumper.pm b/dist/Data-Dumper/Dumper.pm
index e884298..7801511 100644 (file)
--- a/dist/Data-Dumper/Dumper.pm
+++ b/dist/Data-Dumper/Dumper.pm
@@ -10,7 +10,7 @@
 package Data::Dumper;
 
 BEGIN {
-    $VERSION = '2.158'; # Don't forget to set version and release
+    $VERSION = '2.159'; # Don't forget to set version and release
 }               # date in POD below!
 
 #$| = 1;
@@ -1454,7 +1454,7 @@ modify it under the same terms as Perl itself.
 
 =head1 VERSION
 
-Version 2.158  (March 13 2015)
+Version 2.159  (December 15 2015)
 
 =head1 SEE ALSO
 

diff --git a/dist/Data-Dumper/Dumper.xs b/dist/Data-Dumper/Dumper.xs
index 97277f4..b5fab4d 100644 (file)
--- a/dist/Data-Dumper/Dumper.xs
+++ b/dist/Data-Dumper/Dumper.xs
@@ -41,6 +41,29 @@
                           || (((UV) (c)) >= '0' && ((UV) (c)) <= '9'))
 #endif
 
+/* This struct contains almost all the user's desired configuration, and it
+ * is treated as constant by the recursive function. This arrangement has
+ * the advantage of needing less memory than passing all of them on the
+ * stack all the time (as was the case in an earlier implementation). But
+ * this means that, for example, "sortkeys" is a separate parameter. */
+typedef struct {
+    I32 indent;
+    SV *pad;
+    SV *xpad;
+    SV *sep;
+    SV *pair;
+    SV *freezer;
+    SV *toaster;
+    I32 purity;
+    I32 deepcopy;
+    I32 quotekeys;
+    SV *bless;
+    I32 maxdepth;
+    int use_sparse_seen_hash;
+    I32 useqq;
+    IV maxrecurse;
+} Style;
+
 static I32 num_q (const char *s, STRLEN slen);
 static I32 esc_q (char *dest, const char *src, STRLEN slen);
 static I32 esc_q_utf8 (pTHX_ SV *sv, const char *src, STRLEN slen, I32 do_utf8, I32 useqq);
@@ -49,11 +72,8 @@ static bool key_needs_quote(const char *s, STRLEN len);
 static bool safe_decimal_number(const char *p, STRLEN len);
 static SV *sv_x (pTHX_ SV *sv, const char *str, STRLEN len, I32 n);
 static I32 DD_dump (pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval,
-                   HV *seenhv, AV *postav, I32 *levelp, I32 indent,
-                   SV *pad, SV *xpad, SV *apad, SV *sep, SV *pair,
-                   SV *freezer, SV *toaster,
-                   I32 purity, I32 deepcopy, I32 quotekeys, SV *bless,
-                   I32 maxdepth, SV *sortkeys, int use_sparse_seen_hash, I32 useqq, IV maxrecurse);
+                    HV *seenhv, AV *postav, I32 *levelp, SV *apad, SV *sortkeys,
+                    const Style *style);
 
 #ifndef HvNAME_get
 #define HvNAME_get HvNAME
@@ -491,10 +511,7 @@ sv_x(pTHX_ SV *sv, const char *str, STRLEN len, I32 n)
  */
 static I32
 DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
-       AV *postav, I32 *levelp, I32 indent, SV *pad, SV *xpad,
-       SV *apad, SV *sep, SV *pair, SV *freezer, SV *toaster, I32 purity,
-       I32 deepcopy, I32 quotekeys, SV *bless, I32 maxdepth, SV *sortkeys,
-        int use_sparse_seen_hash, I32 useqq, IV maxrecurse)
+       AV *postav, I32 *levelp, SV *apad, SV *sortkeys, const Style *style)
 {
     char tmpbuf[128];
     Size_t i;
@@ -537,14 +554,14 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
 
         /* If a freeze method is provided and the object has it, call
            it.  Warn on errors. */
-       if (SvOBJECT(SvRV(val)) && freezer &&
-           SvPOK(freezer) && SvCUR(freezer) &&
-            gv_fetchmeth(SvSTASH(SvRV(val)), SvPVX_const(freezer), 
-                         SvCUR(freezer), -1) != NULL)
+        if (SvOBJECT(SvRV(val)) && style->freezer &&
+            SvPOK(style->freezer) && SvCUR(style->freezer) &&
+            gv_fetchmeth(SvSTASH(SvRV(val)), SvPVX_const(style->freezer),
+                         SvCUR(style->freezer), -1) != NULL)
        {
            dSP; ENTER; SAVETMPS; PUSHMARK(sp);
            XPUSHs(val); PUTBACK;
-           i = perl_call_method(SvPVX_const(freezer), G_EVAL|G_VOID|G_DISCARD);
+            i = perl_call_method(SvPVX_const(style->freezer), G_EVAL|G_VOID|G_DISCARD);
            SPAGAIN;
            if (SvTRUE(ERRSV))
                warn("WARNING(Freezer method call failed): %"SVf"", ERRSV);
@@ -575,7 +592,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                if ((svp = av_fetch(seenentry, 0, FALSE))
                    && (othername = *svp))
                {
-                   if (purity && *levelp > 0) {
+                   if (style->purity && *levelp > 0) {
                        SV *postentry;
                        
                        if (realtype == SVt_PVHV)
@@ -662,7 +679,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
         * representation of the thing we are currently examining
         * at this depth (i.e., 'Foo=ARRAY(0xdeadbeef)').
         */
-       if (!purity && maxdepth > 0 && *levelp >= maxdepth) {
+        if (!style->purity && style->maxdepth > 0 && *levelp >= style->maxdepth) {
            STRLEN vallen;
            const char * const valstr = SvPV(val,vallen);
            sv_catpvs(retval, "'");
@@ -671,16 +688,16 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
            return 1;
        }
 
-       if (maxrecurse > 0 && *levelp >= maxrecurse) {
-           croak("Recursion limit of %" IVdf " exceeded", maxrecurse);
+        if (style->maxrecurse > 0 && *levelp >= style->maxrecurse) {
+            croak("Recursion limit of %" IVdf " exceeded", style->maxrecurse);
        }
 
        if (realpack && !no_bless) {                            /* we have a blessed ref */
            STRLEN blesslen;
-           const char * const blessstr = SvPV(bless, blesslen);
+            const char * const blessstr = SvPV(style->bless, blesslen);
            sv_catpvn(retval, blessstr, blesslen);
            sv_catpvs(retval, "( ");
-           if (indent >= 2) {
+            if (style->indent >= 2) {
                blesspad = apad;
                apad = newSVsv(apad);
                sv_x(aTHX_ apad, " ", 1, blesslen+2);
@@ -688,7 +705,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
        }
 
        (*levelp)++;
-       ipad = sv_x(aTHX_ Nullsv, SvPVX_const(xpad), SvCUR(xpad), *levelp);
+        ipad = sv_x(aTHX_ Nullsv, SvPVX_const(style->xpad), SvCUR(style->xpad), *levelp);
 
         if (is_regex) 
         {
@@ -759,19 +776,13 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
            if (realpack) {                                  /* blessed */
                sv_catpvs(retval, "do{\\(my $o = ");
                DD_dump(aTHX_ ival, SvPVX_const(namesv), SvCUR(namesv), retval, seenhv,
-                       postav, levelp, indent, pad, xpad, apad, sep, pair,
-                       freezer, toaster, purity, deepcopy, quotekeys, bless,
-                       maxdepth, sortkeys, use_sparse_seen_hash, useqq,
-                       maxrecurse);
+                       postav, levelp, apad, sortkeys, style);
                sv_catpvs(retval, ")}");
            }                                                /* plain */
            else {
                sv_catpvs(retval, "\\");
                DD_dump(aTHX_ ival, SvPVX_const(namesv), SvCUR(namesv), retval, seenhv,
-                       postav, levelp, indent, pad, xpad, apad, sep, pair,
-                       freezer, toaster, purity, deepcopy, quotekeys, bless,
-                       maxdepth, sortkeys, use_sparse_seen_hash, useqq,
-                       maxrecurse);
+                       postav, levelp, apad, sortkeys, style);
            }
            SvREFCNT_dec(namesv);
        }
@@ -781,10 +792,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
            sv_catpvs(namesv, "}");
            sv_catpvs(retval, "\\");
            DD_dump(aTHX_ ival, SvPVX_const(namesv), SvCUR(namesv), retval, seenhv,
-                   postav, levelp,     indent, pad, xpad, apad, sep, pair,
-                   freezer, toaster, purity, deepcopy, quotekeys, bless,
-                   maxdepth, sortkeys, use_sparse_seen_hash, useqq,
-                   maxrecurse);
+                   postav, levelp, apad, sortkeys, style);
            SvREFCNT_dec(namesv);
        }
        else if (realtype == SVt_PVAV) {
@@ -824,8 +832,8 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                iname[inamelen++] = '-'; iname[inamelen++] = '>';
            }
            iname[inamelen++] = '['; iname[inamelen] = '\0';
-           totpad = newSVsv(sep);
-           sv_catsv(totpad, pad);
+            totpad = newSVsv(style->sep);
+            sv_catsv(totpad, style->pad);
            sv_catsv(totpad, apad);
 
            for (ix = 0; ix <= ixmax; ++ix) {
@@ -846,7 +854,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                 ilen = ilen + my_sprintf(iname+ilen, "%"IVdf, (IV)ix);
 #endif
                iname[ilen++] = ']'; iname[ilen] = '\0';
-               if (indent >= 3) {
+                if (style->indent >= 3) {
                    sv_catsv(retval, totpad);
                    sv_catsv(retval, ipad);
                    sv_catpvs(retval, "#");
@@ -855,15 +863,12 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                sv_catsv(retval, totpad);
                sv_catsv(retval, ipad);
                DD_dump(aTHX_ elem, iname, ilen, retval, seenhv, postav,
-                       levelp, indent, pad, xpad, apad, sep, pair,
-                       freezer, toaster, purity, deepcopy, quotekeys, bless,
-                       maxdepth, sortkeys, use_sparse_seen_hash,
-                       useqq, maxrecurse);
+                       levelp, apad, sortkeys, style);
                if (ix < ixmax)
                    sv_catpvs(retval, ",");
            }
            if (ixmax >= 0) {
-               SV * const opad = sv_x(aTHX_ Nullsv, SvPVX_const(xpad), SvCUR(xpad), (*levelp)-1);
+                SV * const opad = sv_x(aTHX_ Nullsv, SvPVX_const(style->xpad), SvCUR(style->xpad), (*levelp)-1);
                sv_catsv(retval, totpad);
                sv_catsv(retval, opad);
                SvREFCNT_dec(opad);
@@ -909,8 +914,8 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                sv_catpvs(iname, "->");
            }
            sv_catpvs(iname, "{");
-           totpad = newSVsv(sep);
-           sv_catsv(totpad, pad);
+            totpad = newSVsv(style->sep);
+            sv_catsv(totpad, style->pad);
            sv_catsv(totpad, apad);
        
            /* If requested, get a sorted/filtered array of hash keys */
@@ -1022,10 +1027,10 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                    their handling of key quoting compatible between XS
                    and perl.
                  */
-                if (quotekeys || key_needs_quote(key,keylen)) {
-                    if (do_utf8 || useqq) {
+                if (style->quotekeys || key_needs_quote(key,keylen)) {
+                    if (do_utf8 || style->useqq) {
                         STRLEN ocur = SvCUR(retval);
-                        nlen = esc_q_utf8(aTHX_ retval, key, klen, do_utf8, useqq);
+                        nlen = esc_q_utf8(aTHX_ retval, key, klen, do_utf8, style->useqq);
                         nkey = SvPVX(retval) + ocur;
                     }
                     else {
@@ -1052,8 +1057,8 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                 sv_catpvn(sname, nkey, nlen);
                 sv_catpvs(sname, "}");
 
-               sv_catsv(retval, pair);
-               if (indent >= 2) {
+                sv_catsv(retval, style->pair);
+                if (style->indent >= 2) {
                    char *extra;
                    I32 elen = 0;
                    newapad = newSVsv(apad);
@@ -1068,17 +1073,15 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                    newapad = apad;
 
                DD_dump(aTHX_ hval, SvPVX_const(sname), SvCUR(sname), retval, seenhv,
-                       postav, levelp, indent, pad, xpad, newapad, sep, pair,
-                       freezer, toaster, purity, deepcopy, quotekeys, bless,
-                       maxdepth, sortkeys, use_sparse_seen_hash, useqq,
-                       maxrecurse);
+                       postav, levelp, newapad, sortkeys, style);
                SvREFCNT_dec(sname);
                Safefree(nkey_buffer);
-               if (indent >= 2)
+                if (style->indent >= 2)
                    SvREFCNT_dec(newapad);
            }
            if (i) {
-               SV *opad = sv_x(aTHX_ Nullsv, SvPVX_const(xpad), SvCUR(xpad), *levelp-1);
+                SV *opad = sv_x(aTHX_ Nullsv, SvPVX_const(style->xpad),
+                                SvCUR(style->xpad), *levelp-1);
                sv_catsv(retval, totpad);
                sv_catsv(retval, opad);
                SvREFCNT_dec(opad);
@@ -1092,7 +1095,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
        }
        else if (realtype == SVt_PVCV) {
            sv_catpvs(retval, "sub { \"DUMMY\" }");
-           if (purity)
+            if (style->purity)
                warn("Encountered CODE ref, using dummy placeholder");
        }
        else {
@@ -1103,7 +1106,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
            I32 plen;
            I32 pticks;
 
-           if (indent >= 2) {
+            if (style->indent >= 2) {
                SvREFCNT_dec(apad);
                apad = blesspad;
            }
@@ -1127,9 +1130,9 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                sv_catpvn(retval, realpack, strlen(realpack));
            }
            sv_catpvs(retval, "' )");
-           if (toaster && SvPOK(toaster) && SvCUR(toaster)) {
+            if (style->toaster && SvPOK(style->toaster) && SvCUR(style->toaster)) {
                sv_catpvs(retval, "->");
-               sv_catsv(retval, toaster);
+                sv_catsv(retval, style->toaster);
                sv_catpvs(retval, "()");
            }
        }
@@ -1168,7 +1171,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
              * there is no other reference, duh. This is an optimization.
              * Note that we'd have to check for weak-refs, too, but this is
              * already the branch for non-refs only. */
-           else if (val != &PL_sv_undef && (!use_sparse_seen_hash || SvREFCNT(val) > 1)) {
+            else if (val != &PL_sv_undef && (!style->use_sparse_seen_hash || SvREFCNT(val) > 1)) {
                SV * const namesv = newSVpvs("\\");
                sv_catpvn(namesv, name, namelen);
                seenentry = newAV();
@@ -1219,7 +1222,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                r = SvPVX(retval)+SvCUR(retval);
                r[0] = '*'; r[1] = '{';
                SvCUR_set(retval, SvCUR(retval)+2);
-               esc_q_utf8(aTHX_ retval, c, i, 1, useqq);
+                esc_q_utf8(aTHX_ retval, c, i, 1, style->useqq);
                sv_grow(retval, SvCUR(retval)+2);
                r = SvPVX(retval)+SvCUR(retval);
                r[0] = '}'; r[1] = '\0';
@@ -1245,7 +1248,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
            }
            SvCUR_set(retval, SvCUR(retval)+i);
 
-           if (purity) {
+            if (style->purity) {
                static const char* const entries[] = { "{SCALAR}", "{ARRAY}", "{HASH}" };
                static const STRLEN sizes[] = { 8, 7, 6 };
                SV *e;
@@ -1272,15 +1275,11 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
                        e = newRV_inc(e);
                        
                        SvCUR_set(newapad, 0);
-                       if (indent >= 2)
+                        if (style->indent >= 2)
                            (void)sv_x(aTHX_ newapad, " ", 1, SvCUR(postentry));
                        
                        DD_dump(aTHX_ e, SvPVX_const(nname), SvCUR(nname), postentry,
-                               seenhv, postav, &nlevel, indent, pad, xpad,
-                               newapad, sep, pair, freezer, toaster, purity,
-                               deepcopy, quotekeys, bless, maxdepth, 
-                               sortkeys, use_sparse_seen_hash, useqq,
-                               maxrecurse);
+                               seenhv, postav, &nlevel, newapad, sortkeys, style);
                        SvREFCNT_dec(e);
                    }
                }
@@ -1315,11 +1314,11 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
              * the pure perl code.
              * see [perl #74798]
              */
-            if (useqq && safe_decimal_number(c, i)) {
+            if (style->useqq && safe_decimal_number(c, i)) {
                 sv_catsv(retval, val);
             }
-           else if (DO_UTF8(val) || useqq)
-               i += esc_q_utf8(aTHX_ retval, c, i, DO_UTF8(val), useqq);
+            else if (DO_UTF8(val) || style->useqq)
+                i += esc_q_utf8(aTHX_ retval, c, i, DO_UTF8(val), style->useqq);
            else {
                sv_grow(retval, SvCUR(retval)+3+2*i); /* 3: ""\0 */
                r = SvPVX(retval) + SvCUR(retval);
@@ -1334,7 +1333,7 @@ DD_dump(pTHX_ SV *val, const char *name, STRLEN namelen, SV *retval, HV *seenhv,
     }
 
     if (idlen) {
-       if (deepcopy)
+        if (style->deepcopy)
            (void)hv_delete(seenhv, id, idlen, G_DISCARD);
        else if (namelen && seenentry) {
            SV *mark = *av_fetch(seenentry, 2, TRUE);
@@ -1364,16 +1363,16 @@ Data_Dumper_Dumpxs(href, ...)
            HV *seenhv = NULL;
            AV *postav, *todumpav, *namesav;
            I32 level = 0;
-           I32 indent, terse, useqq;
+           I32 terse = 0;
            SSize_t i, imax, postlen;
            SV **svp;
-           SV *val, *name, *pad, *xpad, *apad, *sep, *pair, *varname;
-           SV *freezer, *toaster, *bless, *sortkeys;
-           I32 purity, deepcopy, quotekeys, maxdepth = 0;
-           IV maxrecurse = 1000;
+            SV *apad = &PL_sv_undef;
+            SV *sortkeys = &PL_sv_undef;
+            Style style;
+
+            SV *name, *val = &PL_sv_undef, *varname = &PL_sv_undef;
            char tmpbuf[1024];
            I32 gimme = GIMME_V;
-            int use_sparse_seen_hash = 0;
 
            if (!SvROK(href)) {         /* call new to get an object first */
                if (items < 2)
@@ -1402,13 +1401,15 @@ Data_Dumper_Dumpxs(href, ...)
            }
 
            todumpav = namesav = NULL;
+            style.indent = 2;
+            style.quotekeys = 1;
+            style.maxrecurse = 1000;
+            style.purity = style.deepcopy = style.useqq = style.maxdepth
+                = style.use_sparse_seen_hash = 0;
+            style.pad = style.xpad = style.sep = style.pair
+                = style.freezer = style.toaster = style.bless = &PL_sv_undef;
            seenhv = NULL;
-           val = pad = xpad = apad = sep = pair = varname
-               = freezer = toaster = bless = sortkeys = &PL_sv_undef;
            name = sv_newmortal();
-           indent = 2;
-           terse = purity = deepcopy = useqq = 0;
-           quotekeys = 1;
        
            retval = newSVpvs("");
            if (SvROK(href)
@@ -1418,47 +1419,47 @@ Data_Dumper_Dumpxs(href, ...)
                if ((svp = hv_fetch(hv, "seen", 4, FALSE)) && SvROK(*svp))
                    seenhv = (HV*)SvRV(*svp);
                 else
-                    use_sparse_seen_hash = 1;
+                    style.use_sparse_seen_hash = 1;
                if ((svp = hv_fetch(hv, "noseen", 6, FALSE)))
-                   use_sparse_seen_hash = (SvOK(*svp) && SvIV(*svp) != 0);
+                    style.use_sparse_seen_hash = (SvOK(*svp) && SvIV(*svp) != 0);
                if ((svp = hv_fetch(hv, "todump", 6, FALSE)) && SvROK(*svp))
                    todumpav = (AV*)SvRV(*svp);
                if ((svp = hv_fetch(hv, "names", 5, FALSE)) && SvROK(*svp))
                    namesav = (AV*)SvRV(*svp);
                if ((svp = hv_fetch(hv, "indent", 6, FALSE)))
-                   indent = SvIV(*svp);
+                    style.indent = SvIV(*svp);
                if ((svp = hv_fetch(hv, "purity", 6, FALSE)))
-                   purity = SvIV(*svp);
+                    style.purity = SvIV(*svp);
                if ((svp = hv_fetch(hv, "terse", 5, FALSE)))
                    terse = SvTRUE(*svp);
                if ((svp = hv_fetch(hv, "useqq", 5, FALSE)))
-                   useqq = SvTRUE(*svp);
+                    style.useqq = SvTRUE(*svp);
                if ((svp = hv_fetch(hv, "pad", 3, FALSE)))
-                   pad = *svp;
+                    style.pad = *svp;
                if ((svp = hv_fetch(hv, "xpad", 4, FALSE)))
-                   xpad = *svp;
+                    style.xpad = *svp;
                if ((svp = hv_fetch(hv, "apad", 4, FALSE)))
                    apad = *svp;
                if ((svp = hv_fetch(hv, "sep", 3, FALSE)))
-                   sep = *svp;
+                    style.sep = *svp;
                if ((svp = hv_fetch(hv, "pair", 4, FALSE)))
-                   pair = *svp;
+                    style.pair = *svp;
                if ((svp = hv_fetch(hv, "varname", 7, FALSE)))
                    varname = *svp;
                if ((svp = hv_fetch(hv, "freezer", 7, FALSE)))
-                   freezer = *svp;
+                    style.freezer = *svp;
                if ((svp = hv_fetch(hv, "toaster", 7, FALSE)))
-                   toaster = *svp;
+                    style.toaster = *svp;
                if ((svp = hv_fetch(hv, "deepcopy", 8, FALSE)))
-                   deepcopy = SvTRUE(*svp);
+                    style.deepcopy = SvTRUE(*svp);
                if ((svp = hv_fetch(hv, "quotekeys", 9, FALSE)))
-                   quotekeys = SvTRUE(*svp);
+                    style.quotekeys = SvTRUE(*svp);
                if ((svp = hv_fetch(hv, "bless", 5, FALSE)))
-                   bless = *svp;
+                    style.bless = *svp;
                if ((svp = hv_fetch(hv, "maxdepth", 8, FALSE)))
-                   maxdepth = SvIV(*svp);
+                    style.maxdepth = SvIV(*svp);
                if ((svp = hv_fetch(hv, "maxrecurse", 10, FALSE)))
-                   maxrecurse = SvIV(*svp);
+                    style.maxrecurse = SvIV(*svp);
                if ((svp = hv_fetch(hv, "sortkeys", 8, FALSE))) {
                    sortkeys = *svp;
                    if (! SvTRUE(sortkeys))
@@ -1525,7 +1526,7 @@ Data_Dumper_Dumpxs(href, ...)
                        sv_catpvn(name, tmpbuf, nchars);
                    }
                
-                   if (indent >= 2 && !terse) {
+                    if (style.indent >= 2 && !terse) {
                        SV * const tmpsv = sv_x(aTHX_ NULL, " ", 1, SvCUR(name)+3);
                        newapad = newSVsv(apad);
                        sv_catsv(newapad, tmpsv);
@@ -1536,13 +1537,10 @@ Data_Dumper_Dumpxs(href, ...)
                
                    PUTBACK;
                    DD_dump(aTHX_ val, SvPVX_const(name), SvCUR(name), valstr, seenhv,
-                           postav, &level, indent, pad, xpad, newapad, sep, pair,
-                           freezer, toaster, purity, deepcopy, quotekeys,
-                           bless, maxdepth, sortkeys, use_sparse_seen_hash,
-                           useqq, maxrecurse);
+                            postav, &level, newapad, sortkeys, &style);
                    SPAGAIN;
                
-                   if (indent >= 2 && !terse)
+                    if (style.indent >= 2 && !terse)
                        SvREFCNT_dec(newapad);
 
                    postlen = av_len(postav);
@@ -1551,12 +1549,12 @@ Data_Dumper_Dumpxs(href, ...)
                        sv_insert(valstr, 0, 0, SvPVX_const(name), SvCUR(name));
                        sv_catpvs(valstr, ";");
                    }
-                   sv_catsv(retval, pad);
+                    sv_catsv(retval, style.pad);
                    sv_catsv(retval, valstr);
-                   sv_catsv(retval, sep);
+                    sv_catsv(retval, style.sep);
                    if (postlen >= 0) {
                        SSize_t i;
-                       sv_catsv(retval, pad);
+                        sv_catsv(retval, style.pad);
                        for (i = 0; i <= postlen; ++i) {
                            SV *elem;
                            svp = av_fetch(postav, i, FALSE);
@@ -1564,13 +1562,13 @@ Data_Dumper_Dumpxs(href, ...)
                                sv_catsv(retval, elem);
                                if (i < postlen) {
                                    sv_catpvs(retval, ";");
-                                   sv_catsv(retval, sep);
-                                   sv_catsv(retval, pad);
+                                    sv_catsv(retval, style.sep);
+                                    sv_catsv(retval, style.pad);
                                }
                            }
                        }
                        sv_catpvs(retval, ";");
-                           sv_catsv(retval, sep);
+                        sv_catsv(retval, style.sep);
                    }
                    sv_setpvn(valstr, "", 0);
                    if (gimme == G_ARRAY) {