other/3409: [PATCH] ap_md5_binary uses sprintf, which is unnecessarily slow

[Ronald Tschal�r <ro...@innovation.ch>]

>Number:         3409
>Category:       other
>Synopsis:       [PATCH] ap_md5_binary uses sprintf, which is unnecessarily slow
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    apache
>State:          open
>Class:          sw-bug
>Submitter-Id:   apache
>Arrival-Date:   Tue Nov 17 17:20:00 PST 1998
>Last-Modified:
>Originator:     ronald@innovation.ch
>Organization:
apache
>Release:        1.3.*
>Environment:
all
>Description:
ap_md5_binary() (in util_md5.c) uses sprintf to convert the hash to hex form,
but this is pretty slow (mod_digest spends ove 10% of its time in this sprintf).
The simple attached patch solves this.
>How-To-Repeat:

>Fix:
Diff for apache-1.3.4-dev:

--- main/util_md5.c.orig        Sun Sep  6 12:12:18 1998
+++ main/util_md5.c     Tue Nov 17 15:59:32 1998
@@ -89,6 +89,7 @@
 
 API_EXPORT(char *) ap_md5_binary(pool *p, const unsigned char *buf, int length)
 {
+    static char hex[] = "0123456789abcdef";
     AP_MD5_CTX my_md5;
     unsigned char hash[16];
     char *r, result[33];
@@ -102,8 +103,10 @@
     ap_MD5Update(&my_md5, buf, length);
     ap_MD5Final(hash, &my_md5);
 
-    for (i = 0, r = result; i < 16; i++, r += 2)
-       sprintf(r, "%02x", hash[i]);
+    for (i = 0, r = result; i < 16; i++) {
+       *r++ = hex[hash[i] >> 4];
+       *r++ = hex[hash[i] & 0xF];
+    }
     *r = '\0';
 
     return ap_pstrdup(p, result);
>Audit-Trail:
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