Use an explicit table for tolower() to avoid a function call

On some platforms, tolower() is implemented as a function call, in
order to handle locale support.  We never change locales, so can the
result of tolower() into a table, so we don't have to sit through the
function call every time.

~1.3% overall performance improvement on a macro-heavy benchmark under
Linux x86-64.

1 files changed, 2 insertions, 1 deletions

diff --git a/ndisasm.c b/ndisasm.c
index 8f912f8..b5001bd 100644
--- a/ndisasm.c
+++ b/ndisasm.c
@@ -67,6 +67,7 @@ int main(int argc, char **argv)
     int32_t offset;
     FILE *fp;
 
+    tolower_init();
     nasm_set_malloc_error(ndisasm_error);
 
     offset = 0;
@@ -77,7 +78,7 @@ int main(int argc, char **argv)
         if (*p == '-' && p[1]) {
             p++;
             while (*p)
-                switch (tolower(*p)) {
+                switch (nasm_tolower(*p)) {
                 case 'a':      /* auto or intelligent sync */
                 case 'i':
                     autosync = true;