commands: cheap optimisation for parser

Some low-hanging fruits to cut of signification number of strcmp calls.

diff --git a/tools/command.c b/tools/command.c
index 5b31b4ef25556a096f4875d23864b8dfa74cefbe..f1b9d8e676f4b51c884acee5265135258336363b 100644 (file)
--- a/tools/command.c
+++ b/tools/command.c
@@ -495,31 +495,32 @@ static struct command_name *find_command_name(const char *name)
 {
        int i;
 
+       if (!islower(name[0]))
+               return NULL; /* Commands starts with lower-case */
+
        for (i = 0; i < MAX_COMMAND_NAMES; i++) {
                if (!command_names[i].name)
                        break;
                if (!strcmp(command_names[i].name, name))
                        return &command_names[i];
        }
+
        return NULL;
 }
 
 static const char *is_command_name(char *str)
 {
-       int i;
+       const struct command_name *c;
+
+       if ((c = find_command_name(str)))
+               return c->name;
 
-       for (i = 0; i < MAX_COMMAND_NAMES; i++) {
-               if (!command_names[i].name)
-                       break;
-               if (!strcmp(command_names[i].name, str))
-                       return command_names[i].name;
-       }
        return NULL;
 }
 
 static int is_opt_name(char *str)
 {
-       if (!strncmp(str, "--", 2))
+       if ((str[0] == '-') && (str[1] == '-'))
                return 1;
 
        if ((str[0] == '-') && (str[1] != '-'))
@@ -535,18 +536,15 @@ static int is_opt_name(char *str)
 
 static int is_pos_name(char *str)
 {
-       if (!strncmp(str, "VG", 2))
-               return 1;
-       if (!strncmp(str, "LV", 2))
-               return 1;
-       if (!strncmp(str, "PV", 2))
-               return 1;
-       if (!strncmp(str, "Tag", 3))
-               return 1;
-       if (!strncmp(str, "String", 6))
-               return 1;
-       if (!strncmp(str, "Select", 6))
-               return 1;
+       switch (str[0]) {
+       case 'V': return (str[1] == 'G'); /* VG */
+       case 'L': return (str[1] == 'V'); /* LV */
+       case 'P': return (str[1] == 'V'); /* PV */
+       case 'T': return (strncmp(str, "Tag", 3) == 0);
+       case 'S': return ((strncmp(str, "String", 6) == 0) ||
+                         (strncmp(str, "Select", 6) == 0));
+       }
+
        return 0;
 }