Rewrite index_in_strings() to replace calls to strcmp()/strlen(). With this change searching for valid names in the applet_names array (for example) is 40% faster.
The code has to assume the strings aren't sorted, so will always scan the entire array when presented with an invalid name. function old new delta index_in_strings 63 56 -7 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-7) Total: -7 bytes Signed-off-by: Ron Yorston <[email protected]> --- libbb/compare_string_array.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/libbb/compare_string_array.c b/libbb/compare_string_array.c index a06e57d3d..f38168d7e 100644 --- a/libbb/compare_string_array.c +++ b/libbb/compare_string_array.c @@ -63,13 +63,19 @@ int FAST_FUNC index_in_str_array(const char *const string_array[], const char *k int FAST_FUNC index_in_strings(const char *strings, const char *key) { - int idx = 0; + int j, idx = 0; while (*strings) { - if (strcmp(strings, key) == 0) { - return idx; + /* Do we see "key\0" at current position in strings? */ + for (j = 0; *strings == key[j]; ++j) { + if (*strings++ == '\0') { + //bb_error_msg("found:'%s' i:%u", key, idx); + return idx; /* yes */ + } } - strings += strlen(strings) + 1; /* skip NUL */ + /* No. Move to the start of the next string. */ + while (*strings++ != '\0') + ; idx++; } return -1; -- 2.29.2 _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
