[MINOR] halog: gain back performance before SKIP_CHAR fix

The SKIP_CHAR fix caused a measurable performance drop. Since we can
consider all chars below 0x20 as delimiters, we can avoid a cache lookup
which requires a char to pointer conversion.

diff --git a/contrib/halog/halog.c b/contrib/halog/halog.c
index 6478981047c5167b7eda20d109c4ae9f787159c8..82f179a4c5f3f34f2bc1936a95db881a274ebd9d 100644 (file)
--- a/contrib/halog/halog.c
+++ b/contrib/halog/halog.c
@@ -36,13 +36,8 @@
 #define MAXLINE 16384
 #define QBITS 4
 
-const char sep[256] = {
-        [0] = 1,
-       [' '] = 1, ['\t'] = 1,
-        ['\r'] = 1, ['\n'] = 1,
-};
-
-#define SKIP_CHAR(p,c) do { while (1) if (sep[(unsigned char)*p]) break; else if (*(p++) == c) break; } while (0)
+#define SEP(c) ((unsigned char)(c) <= ' ')
+#define SKIP_CHAR(p,c) do { while (1) { int __c = (unsigned char)*p++; if (__c == c) break; if (__c <= ' ') { p--; break; } } } while (0)
 
 /* [0] = err/date, [1] = req, [2] = conn, [3] = resp, [4] = data */
 static struct eb_root timers[5] = {
@@ -515,7 +510,7 @@ int main(int argc, char **argv)
                        p = b;
                        err = 0;
                        f = 0;
-                       while (!sep[(unsigned char)*p]) {
+                       while (!SEP(*p)) {
                                if (++f == 4)
                                        break;
                                SKIP_CHAR(p, '/');
@@ -539,7 +534,7 @@ int main(int argc, char **argv)
                        p = b;
                        err = 0;
                        f = 0;
-                       while (!sep[(unsigned char)*p]) {
+                       while (!SEP(*p)) {
                                tps = str2ic(p);
                                if (tps < 0) {
                                        tps = -1;
@@ -612,7 +607,7 @@ int main(int argc, char **argv)
                        p = b;
                        err = 0;
                        f = 0;
-                       while (!sep[(unsigned char)*p]) {
+                       while (!SEP(*p)) {
                                array[f] = str2ic(p);
                                if (array[f] < 0) {
                                        array[f] = -1;
@@ -777,7 +772,7 @@ int main(int argc, char **argv)
                        p = b;
                        err = 0;
                        f = 0;
-                       while (!sep[(unsigned char)*p]) {
+                       while (!SEP(*p)) {
                                array[f] = str2ic(p);
                                if (array[f] < 0) {
                                        array[f] = -1;
@@ -845,7 +840,7 @@ int main(int argc, char **argv)
                         * parse the 5 timers to detect errors, it takes avg 55 ns per line.
                         */
                        e = b; err = 0; f = 0;
-                       while (!sep[(unsigned char)*e]) {
+                       while (!SEP(*e)) {
                                array[f] = str2ic(e);
                                if (array[f] < 0) {
                                        array[f] = -1;