From 5e7aa789c35577c2a092ac2f2d75bcee74e9b7f1 Mon Sep 17 00:00:00 2001
From: Nicholas Clark <nick@ccl4.org>
Date: Fri, 5 Oct 2007 19:48:27 +0000
Subject: [PATCH] Eliminate most *printf-like calls that use a simple "%c"
 format, replacing them with constructions that are more efficient because
 they avoid the overhead of the *printf format parser and interpreter code.

p4raw-id: //depot/perl@32034
---
 dump.c    |  6 ++++--
 regcomp.c | 14 +++++++++-----
 toke.c    |  6 ++++--
 utf8.c    |  6 ++++--
 4 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/dump.c b/dump.c
index dce8630..bdaf41a 100644
--- a/dump.c
+++ b/dump.c
@@ -279,7 +279,8 @@ Perl_pv_escape( pTHX_ SV *dsv, char const * const str,
             sv_catpvn(dsv, octbuf, chsize);
             wrote += chsize;
 	} else {
-            Perl_sv_catpvf( aTHX_ dsv, "%c", c);
+	    const char string = (char) c;
+            sv_catpvn(dsv, &string, 1);
 	    wrote++;
 	}
         if ( flags & PERL_PV_ESCAPE_FIRSTCHAR ) 
@@ -2243,7 +2244,8 @@ Perl_sv_catxmlpvn(pTHX_ SV *dsv, const char *pv, STRLEN len, int utf8)
 		    Perl_sv_catpvf(aTHX_ dsv, "&#x%X;", c);
 		}
 		else {
-		    Perl_sv_catpvf(aTHX_ dsv, "%c", c);
+		    const char string = (char) c;
+		    sv_catpvn(dsv, &string, 1);
 		}
 		break;
 	    }
diff --git a/regcomp.c b/regcomp.c
index dd48f3c..8757eb1 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -6484,6 +6484,7 @@ S_reg_namedseq(pTHX_ RExC_state_t *pRExC_state, UV *valuep)
             | PERL_SCAN_DISALLOW_PREFIX
             | (SIZE_ONLY ? PERL_SCAN_SILENT_ILLDIGIT : 0);
         UV cp;
+	unsigned char string;
         len = (STRLEN)(endbrace - name - 2);
         cp = grok_hex(name + 2, &len, &fl, NULL);
         if ( len != (STRLEN)(endbrace - name - 2) ) {
@@ -6495,7 +6496,8 @@ S_reg_namedseq(pTHX_ RExC_state_t *pRExC_state, UV *valuep)
             *valuep = cp;
             return NULL;
         }
-        sv_str= Perl_newSVpvf_nocontext("%c",(int)cp);
+	string = (unsigned char) cp;
+        sv_str= newSVpvn(&string, 1);
     } else {
         /* fetch the charnames handler for this scope */
         HV * const table = GvHV(PL_hintgv);
@@ -9666,10 +9668,12 @@ S_put_byte(pTHX_ SV *sv, int c)
 {
     if (isCNTRL(c) || c == 255 || !isPRINT(c))
 	Perl_sv_catpvf(aTHX_ sv, "\\%o", c);
-    else if (c == '-' || c == ']' || c == '\\' || c == '^')
-	Perl_sv_catpvf(aTHX_ sv, "\\%c", c);
-    else
-	Perl_sv_catpvf(aTHX_ sv, "%c", c);
+    else {
+	const unsigned char string = (unsigned char) c;
+	if (c == '-' || c == ']' || c == '\\' || c == '^')
+	    sv_catpvs(sv, "\\");
+	sv_catpvn(sv, &string, 1);
+    }
 }
 
 
diff --git a/toke.c b/toke.c
index be7bacf..7037a43 100644
--- a/toke.c
+++ b/toke.c
@@ -12510,8 +12510,10 @@ Perl_yyerror(pTHX_ const char *s)
 	SV * const where_sv = sv_2mortal(newSVpvs("next char "));
 	if (yychar < 32)
 	    Perl_sv_catpvf(aTHX_ where_sv, "^%c", toCTRL(yychar));
-	else if (isPRINT_LC(yychar))
-	    Perl_sv_catpvf(aTHX_ where_sv, "%c", yychar);
+	else if (isPRINT_LC(yychar)) {
+	    const unsigned char string = (unsigned char) yychar;
+	    sv_catpvn(where_sv, &string, 1);
+	}
 	else
 	    Perl_sv_catpvf(aTHX_ where_sv, "\\%03o", yychar & 255);
 	where = SvPVX_const(where_sv);
diff --git a/utf8.c b/utf8.c
index a761d82..c665a41 100644
--- a/utf8.c
+++ b/utf8.c
@@ -2167,12 +2167,14 @@ Perl_pv_uni_display(pTHX_ SV *dsv, const U8 *spv, STRLEN len, STRLEN pvlim, UV f
 		 default: break;
 		 }
 		 if (ok) {
-		     Perl_sv_catpvf(aTHX_ dsv, "\\%c", ok);
+		     const unsigned char string = (unsigned char) ok;
+		     sv_catpvn(dsv, &string, 1);
 		 }
 	     }
 	     /* isPRINT() is the locale-blind version. */
 	     if (!ok && (flags & UNI_DISPLAY_ISPRINT) && isPRINT(c)) {
-	         Perl_sv_catpvf(aTHX_ dsv, "%c", c);
+		 const unsigned char string = (unsigned char) c;
+		 sv_catpvn(dsv, &string, 1);
 		 ok = 1;
 	     }
 	 }
-- 
1.8.3.1