memset() is cheaper than a loop of 256 bit-a-a-times

Message-ID: <20011124163042.R37621@plum.flirble.org>

p4raw-id: //depot/perl@13236

diff --git a/regcomp.c b/regcomp.c
index 3eb4e39..c73e815 100644 (file)
--- a/regcomp.c
+++ b/regcomp.c
@@ -522,11 +522,8 @@ S_scan_commit(pTHX_ RExC_state_t *pRExC_state, scan_data_t *data)
 STATIC void
 S_cl_anything(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
 {
-    int value;
-
     ANYOF_CLASS_ZERO(cl);
-    for (value = 0; value < 256; ++value)
-       ANYOF_BITMAP_SET(cl, value);
+    ANYOF_BITMAP_SETALL(cl);
     cl->flags = ANYOF_EOS|ANYOF_UNICODE_ALL;
     if (LOC)
        cl->flags |= ANYOF_LOCALE;
@@ -543,9 +540,8 @@ S_cl_is_anything(pTHX_ struct regnode_charclass_class *cl)
            return 1;
     if (!(cl->flags & ANYOF_UNICODE_ALL))
        return 0;
-    for (value = 0; value < 256; ++value)
-       if (!ANYOF_BITMAP_TEST(cl, value))
-           return 0;
+    if (!ANYOF_BITMAP_TESTALLSET(cl))
+       return 0;
     return 1;
 }
 

diff --git a/regcomp.h b/regcomp.h
index bbe3a41..16cf957 100644 (file)
--- a/regcomp.h
+++ b/regcomp.h
@@ -286,6 +286,14 @@ struct regnode_charclass_class {   /* has [[:blah:]] classes */
 #define ANYOF_BITMAP_CLEAR(p,c)        (ANYOF_BITMAP_BYTE(p, c) &= ~ANYOF_BIT(c))
 #define ANYOF_BITMAP_TEST(p, c)        (ANYOF_BITMAP_BYTE(p, c) &   ANYOF_BIT(c))
 
+#define ANYOF_BITMAP_SETALL(p)         \
+       memset (ANYOF_BITMAP(p), 255, ANYOF_BITMAP_SIZE)
+#define ANYOF_BITMAP_CLEARALL(p)       \
+       Zero (ANYOF_BITMAP(p), ANYOF_BITMAP_SIZE)
+/* Check that all 256 bits are all set.  Used in S_cl_is_anything()  */
+#define ANYOF_BITMAP_TESTALLSET(p)     \
+       memEQ (ANYOF_BITMAP(p), "\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377", ANYOF_BITMAP_SIZE)
+
 #define ANYOF_SKIP             ((ANYOF_SIZE - 1)/sizeof(regnode))
 #define ANYOF_CLASS_SKIP       ((ANYOF_CLASS_SIZE - 1)/sizeof(regnode))
 #define ANYOF_CLASS_ADD_SKIP   (ANYOF_CLASS_SKIP - ANYOF_SKIP)