httpd: speed up httpd.conf at the cost of 49 bytes of code

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 20 insertions, 8 deletions

diff --git a/networking/httpd.c b/networking/httpd.c
index b8aa02fe4..52b2b2a7a 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -530,27 +530,39 @@ static void parse_conf(const char *path, int flag)
         while (fgets(buf, sizeof(buf), f) != NULL) {
                 unsigned strlen_buf;
                 unsigned char ch;
-                char *after_colon = NULL;
+                char *after_colon;
 
                 { /* remove all whitespace, and # comments */
                         char *p, *p0;
 
-                        p = p0 = buf;
-                        while ((ch = *p0++) != '\0' && ch != '#') {
-                                if (!isspace(ch)) {
+                        p0 = buf;
+                        /* skip non-whitespace beginning. Often the whole line
+                         * is non-whitespace. We want this case to work fast,
+                         * without needless copying, therefore we don't merge
+                         * this operation into next while loop. */
+                        while ((ch = *p0) != '\0' && ch != '\n' && ch != '#'
+                         && ch != ' ' && ch != '\t'
+                        ) {
+                                p0++;
+                        }
+                        p = p0;
+                        /* if we enter this loop, we have some whitespace.
+                         * discard it */
+                        while (ch != '\0' && ch != '\n' && ch != '#') {
+                                if (ch != ' ' && ch != '\t') {
                                         *p++ = ch;
-                                        if (ch == ':' && after_colon == NULL)
-                                                after_colon = p;
                                 }
+                                ch = *++p0;
                         }
                         *p = '\0';
                         strlen_buf = p - buf;
                         if (strlen_buf == 0)
-                                continue;
+                                continue; /* empty line */
                 }
 
+                after_colon = strchr(buf, ':');
                 /* strange line? */
-                if (after_colon == NULL || *after_colon == '\0')
+                if (after_colon == NULL || *++after_colon == '\0')
                         goto config_error;
 
                 ch = (buf[0] & ~0x20); /* toupper if it's a letter */