svn commit: r1897105 - /httpd/httpd/trunk/server/util.c

[yl...@apache.org]

Author: ylavic
Date: Sun Jan 16 00:07:45 2022
New Revision: 1897105

URL: http://svn.apache.org/viewvc?rev=1897105&view=rev
Log:
util: Follow up to r1897101: Yet better ap_cstr_casecmp[n]().

This ones have a shorter prologue (-O2 still).

Dump of assembler code for function ap_cstr_casecmp:
   0x0000000000049fd0 <+0>:	xor    %edx,%edx
   0x0000000000049fd2 <+2>:	lea    0x3d567(%rip),%r8        # 0x87540 <ucharmap>
   0x0000000000049fd9 <+9>:	nopl   0x0(%rax)
   0x0000000000049fe0 <+16>:	movzbl (%rdi,%rdx,1),%eax
   0x0000000000049fe4 <+20>:	movzbl (%rsi,%rdx,1),%ecx
   0x0000000000049fe8 <+24>:	add    $0x1,%rdx
   0x0000000000049fec <+28>:	movzbl (%r8,%rax,1),%eax
   0x0000000000049ff1 <+33>:	movzbl (%r8,%rcx,1),%ecx
   0x0000000000049ff6 <+38>:	cmp    %ecx,%eax
   0x0000000000049ff8 <+40>:	jne    0x49ffe <ap_cstr_casecmp+46>
   0x0000000000049ffa <+42>:	test   %eax,%eax
   0x0000000000049ffc <+44>:	jne    0x49fe0 <ap_cstr_casecmp+16>
   0x0000000000049ffe <+46>:	sub    %ecx,%eax
   0x000000000004a000 <+48>:	ret    
End of assembler dump.


Modified:
    httpd/httpd/trunk/server/util.c

Modified: httpd/httpd/trunk/server/util.c
URL: http://svn.apache.org/viewvc/httpd/httpd/trunk/server/util.c?rev=1897105&r1=1897104&r2=1897105&view=diff
==============================================================================
--- httpd/httpd/trunk/server/util.c (original)
+++ httpd/httpd/trunk/server/util.c Sun Jan 16 00:07:45 2022
@@ -3539,11 +3539,12 @@ static const unsigned char ucharmap[256]
 
 AP_DECLARE(int) ap_cstr_casecmp(const char *s1, const char *s2)
 {
-    apr_size_t i = 0;
-    for (;; ++i) {
-        const int c1 = ucharmap[(unsigned char)s1[i]];
-        const int c2 = ucharmap[(unsigned char)s2[i]];
-        /* Not necessary to test for !c2, this is caught by c1 != c2 */
+    const unsigned char *u1 = (const unsigned char *)s1;
+    const unsigned char *u2 = (const unsigned char *)s2;
+    for (;;) {
+        const int c1 = ucharmap[*u1++];
+        const int c2 = ucharmap[*u2++];
+        /* Not necessary to test for !c2, this is caught by c1 == c2 */
         if (c1 != c2 || !c1)
             return c1 - c2;
     }
@@ -3551,11 +3552,12 @@ AP_DECLARE(int) ap_cstr_casecmp(const ch
 
 AP_DECLARE(int) ap_cstr_casecmpn(const char *s1, const char *s2, apr_size_t n)
 {
-    apr_size_t i = 0;
-    for (; i < n; ++i) {
-        const int c1 = ucharmap[(unsigned char)s1[i]];
-        const int c2 = ucharmap[(unsigned char)s2[i]];
-        /* Not necessary to test for !c2, this is caught by c1 != c2 */
+    const unsigned char *u1 = (const unsigned char *)s1;
+    const unsigned char *u2 = (const unsigned char *)s2;
+    while (n--) {
+        const int c1 = ucharmap[*u1++];
+        const int c2 = ucharmap[*u2++];
+        /* Not necessary to test for !c2, this is caught by c1 == c2 */
         if (c1 != c2 || !c1)
             return c1 - c2;
     }