Switch to faster tolower function for u8_tolower.

src/suricata.c

@@ -781,13 +781,16 @@ int main(int argc, char **argv)
     }
 
     /* create table for O(1) lowercase conversion lookup */
+    /*
     uint8_t c = 0;
+    memset(g_u8_lowercasetable, 0x00, sizeof(g_u8_lowercasetable));
     for ( ; c < 255; c++) {
         if (c >= 'A' && c <= 'Z')
             g_u8_lowercasetable[c] = (c + ('a' - 'A'));
         else
             g_u8_lowercasetable[c] = c;
     }
+    */
     /* hardcoded initialization code */
     MpmTableSetup(); /* load the pattern matchers */
     SigTableSetup(); /* load the rule keywords */

src/suricata.h

@@ -80,12 +80,17 @@ SCDQDataQueue data_queues[256];
 void GlobalInits();
 
 /* uppercase to lowercase conversion lookup table */
-uint8_t g_u8_lowercasetable[256];
+//uint8_t g_u8_lowercasetable[256];
+
 /* marco to do the actual lookup */
-#define u8_tolower(c) g_u8_lowercasetable[(c)]
+//#define u8_tolower(c) g_u8_lowercasetable[(c)]
 // these 2 are slower:
 //#define u8_tolower(c) ((c) >= 'A' && (c) <= 'Z') ? g_u8_lowercasetable[(c)] : (c)
-//#define u8_tolower(c) ((c) >= 'A' && (c) <= 'Z') ? ((c) + ('a' - 'A')) : (c)
+//#define u8_tolower(c) (((c) >= 'A' && (c) <= 'Z') ? ((c) + ('a' - 'A')) : (c))
+
+/* this is faster than the table lookup */
+#include <ctype.h>
+#define u8_tolower(c) tolower((uint8_t)(c))
 
 void EngineStop(void);
 void EngineKill(void);