[CONTRIB] halog: faster fgets() and add support for percentile reporting
A new fgets implementation saves about 25-50% of the time spent parsing
the logs.
Percentile calculation has been added for timers using -pct.
diff --git a/contrib/halog/fgets2.c b/contrib/halog/fgets2.c
new file mode 100644
index 0000000..13918a7
--- /dev/null
+++ b/contrib/halog/fgets2.c
@@ -0,0 +1,138 @@
+/*
+ * fast fgets() replacement for log parsing
+ *
+ * Copyright 2000-2009 Willy Tarreau <w@1wt.eu>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * This function manages its own buffer and returns a pointer to that buffer
+ * in order to avoid expensive memory copies. It also checks for line breaks
+ * 32 bits at a time. It could be improved a lot using mmap() but we would
+ * not be allowed to replace trailing \n with zeroes and we would be limited
+ * to small log files on 32-bit machines.
+ *
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+
+// return 1 if the integer contains at least one zero byte
+static inline unsigned int has_zero(unsigned int x)
+{
+ if (!(x & 0xFF000000U) ||
+ !(x & 0xFF0000U) ||
+ !(x & 0xFF00U) ||
+ !(x & 0xFFU))
+ return 1;
+ return 0;
+}
+
+
+#define FGETS2_BUFSIZE (256*1024)
+const char *fgets2(FILE *stream)
+{
+ static char buffer[FGETS2_BUFSIZE + 5];
+ static char *end = buffer;
+ static char *line = buffer;
+
+ char *next;
+ int ret;
+
+ next = line;
+
+ while (1) {
+ /* this is a speed-up, we read 32 bits at once and check for an
+ * LF character there. We stop if found then continue one at a
+ * time.
+ */
+ while (next < end && (((unsigned long)next) & 3) && *next != '\n')
+ next++;
+
+ /* now next is multiple of 4 or equal to end */
+ while (next <= (end-32)) {
+ if (has_zero(*(unsigned int *)next ^ 0x0A0A0A0A))
+ break;
+ next += 4;
+ if (has_zero(*(unsigned int *)next ^ 0x0A0A0A0A))
+ break;
+ next += 4;
+ if (has_zero(*(unsigned int *)next ^ 0x0A0A0A0A))
+ break;
+ next += 4;
+ if (has_zero(*(unsigned int *)next ^ 0x0A0A0A0A))
+ break;
+ next += 4;
+ if (has_zero(*(unsigned int *)next ^ 0x0A0A0A0A))
+ break;
+ next += 4;
+ if (has_zero(*(unsigned int *)next ^ 0x0A0A0A0A))
+ break;
+ next += 4;
+ if (has_zero(*(unsigned int *)next ^ 0x0A0A0A0A))
+ break;
+ next += 4;
+ if (has_zero(*(unsigned int *)next ^ 0x0A0A0A0A))
+ break;
+ next += 4;
+ }
+
+ /* we finish if needed. Note that next might be slightly higher
+ * than end here because we might have gone past it above.
+ */
+ while (next < end) {
+ if (*next == '\n') {
+ const char *start = line;
+
+ *next = '\0';
+ line = next + 1;
+ return start;
+ }
+ next++;
+ }
+
+ /* we found an incomplete line. First, let's move the
+ * remaining part of the buffer to the beginning, then
+ * try to complete the buffer with a new read.
+ */
+ if (line > buffer) {
+ if (end != line)
+ memmove(buffer, line, end - line);
+ end = buffer + (end - line);
+ next = end;
+ line = buffer;
+ } else {
+ if (end == buffer + FGETS2_BUFSIZE)
+ return NULL;
+ }
+
+ ret = read(fileno(stream), end, buffer + FGETS2_BUFSIZE - end);
+
+ if (ret <= 0) {
+ if (end == line)
+ return NULL;
+
+ *end = '\0';
+ return line;
+ }
+
+ end += ret;
+ /* search for '\n' again */
+ }
+}
+
+#ifdef BENCHMARK
+int main() {
+ const char *p;
+ unsigned int lines = 0;
+
+ while ((p=fgets2(stdin)))
+ lines++;
+ printf("lines=%d\n", lines);
+ return 0;
+}
+#endif