1 | module strings |
2 | |
3 | // strings.repeat - fill a string with `n` repetitions of the character `c` |
4 | [direct_array_access] |
5 | pub fn repeat(c u8, n int) string { |
6 | if n <= 0 { |
7 | return '' |
8 | } |
9 | mut bytes := unsafe { malloc_noscan(n + 1) } |
10 | unsafe { |
11 | C.memset(bytes, c, n) |
12 | bytes[n] = `0` |
13 | } |
14 | return unsafe { bytes.vstring_with_len(n) } |
15 | } |
16 | |
17 | // strings.repeat_string - gives you `n` repetitions of the substring `s` |
18 | // Note: strings.repeat, that repeats a single byte, is between 2x |
19 | // and 24x faster than strings.repeat_string called for a 1 char string. |
20 | [direct_array_access] |
21 | pub fn repeat_string(s string, n int) string { |
22 | if n <= 0 || s.len == 0 { |
23 | return '' |
24 | } |
25 | slen := s.len |
26 | blen := slen * n |
27 | mut bytes := unsafe { malloc_noscan(blen + 1) } |
28 | for bi in 0 .. n { |
29 | bislen := bi * slen |
30 | for si in 0 .. slen { |
31 | unsafe { |
32 | bytes[bislen + si] = s[si] |
33 | } |
34 | } |
35 | } |
36 | unsafe { |
37 | bytes[blen] = `0` |
38 | } |
39 | return unsafe { bytes.vstring_with_len(blen) } |
40 | } |