utf8: ascii_filter() is unused, let's remove it

src/shared/utf8.c

@@ -184,27 +184,6 @@ char *ascii_is_valid(const char *str) {
         return (char*) str;
 }
 
-char *ascii_filter(const char *str) {
-        const char *s;
-        char *r, *d;
-        size_t l;
-
-        assert(str);
-
-        l = strlen(str);
-        r = malloc(l + 1);
-        if (!r)
-                return NULL;
-
-        for (s = str, d = r; *s; s++)
-                if ((unsigned char) *s < 128)
-                        *(d++) = *s;
-
-        *d = 0;
-
-        return r;
-}
-
 char *utf16_to_utf8(const void *s, size_t length) {
         char *r;
         const uint8_t *f;

src/shared/utf8.h

@@ -30,8 +30,6 @@ char *ascii_is_valid(const char *s) _pure_;
 
 bool utf8_is_printable(const char* str, size_t length) _pure_;
 
-char *ascii_filter(const char *s);
-
 char *utf16_to_utf8(const void *s, size_t length);
 
 int utf8_encoded_valid_unichar(const char *str);

src/test/test-utf8.c

@@ -41,22 +41,6 @@ static void test_ascii_is_valid(void) {
         assert_se(!ascii_is_valid("\341\204"));
 }
 
-static void test_ascii_filter(void) {
-        char *f;
-
-        f = ascii_filter("alsdjf\t\vbarr\nba z");
-        assert_se(streq(f, "alsdjf\t\vbarr\nba z"));
-        free(f);
-
-        f = ascii_filter("\342\204\242");
-        assert_se(streq(f, ""));
-        free(f);
-
-        f = ascii_filter("foo\341\204bar");
-        assert_se(streq(f, "foobar"));
-        free(f);
-}
-
 static void test_utf8_encoded_valid_unichar(void) {
         assert_se(utf8_encoded_valid_unichar("\342\204\242") == 3);
         assert_se(utf8_encoded_valid_unichar("\302\256") == 2);
@@ -70,7 +54,6 @@ int main(int argc, char *argv[]) {
         test_utf8_is_valid();
         test_utf8_is_printable();
         test_ascii_is_valid();
-        test_ascii_filter();
         test_utf8_encoded_valid_unichar();
 
         return 0;