From 80b717af0c1c0602537a6e4d5fad76e09733f028 Mon Sep 17 00:00:00 2001 From: Zdenek Kabelac Date: Fri, 17 Feb 2017 11:52:37 +0100 Subject: [PATCH] commands: cheap optimisation for parser Some low-hanging fruits to cut of signification number of strcmp calls. --- tools/command.c | 38 ++++++++++++++++++-------------------- 1 file changed, 18 insertions(+), 20 deletions(-) diff --git a/tools/command.c b/tools/command.c index 5b31b4ef2..f1b9d8e67 100644 --- 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; } -- 2.43.5