From: Nick Bowler <nbowler@draconx.ca>
Date: Sun, 19 Nov 2023 01:05:23 +0000 (-0500)
Subject: libcdecl: Prefer memchr over strchr in the scanner.
X-Git-Tag: v1.3~82
X-Git-Url: https://git.draconx.ca/gitweb/cdecl99.git/commitdiff_plain/82cedba63a97c4afde1440751585759888384883

libcdecl: Prefer memchr over strchr in the scanner.

Since nothing else in the library uses strchr, but we do use memchr
elsewhere, using memchr instead avoids a comparatively expensive PLT
entry.  We already know the string length so the only real difference
is the additional argument marshalling.
---

diff --git a/src/scan.l b/src/scan.l
index 7549e6f..2b92846 100644
--- a/src/scan.l
+++ b/src/scan.l
@@ -157,9 +157,10 @@ INTEGER 0x[[:xdigit:]]+|0[0-7]+|[[:digit:]]+
 }
 
 {IDENT} {
-	unsigned x = cdecl__to_keyword(yytext, yyleng, yyextra);
-	int tok;
+	int len = yyleng, tok;
+	unsigned x;
 
+	x = cdecl__to_keyword(yytext, len, yyextra);
 	yylval->spectype = UNPACK_SPEC(x & 0xff);
 	if ((tok = (x >> 8)) == PACK_TOKEN(T_IDENT)) {
 		/*
@@ -173,14 +174,14 @@ INTEGER 0x[[:xdigit:]]+|0[0-7]+|[[:digit:]]+
 		 * downsides.
 		 */
 #if 1
-		if ((c = strchr(yytext, '-')))
+		if ((c = memchr(yytext, '-', len)))
 			goto invalid_char;
 #else
 		yyless(strcspn(yytext, "-"));
 #endif
-		if (!(yylval->item = cdecl__alloc_item(yyleng+1)))
+		if (!(yylval->item = cdecl__alloc_item(len+1)))
 			return T_LEX_ERROR; \
-		memcpy(yylval->item->s, yytext, yyleng+1);
+		memcpy(yylval->item->s, yytext, len+1);
 	}
 	return UNPACK_TOKEN(tok);
 }