1 | /* stringlib: replace implementation */ |
2 | |
3 | #ifndef STRINGLIB_FASTSEARCH_H |
4 | #error must include "stringlib/fastsearch.h" before including this module |
5 | #endif |
6 | |
7 | Py_LOCAL_INLINE(void) |
8 | STRINGLIB(replace_1char_inplace)(STRINGLIB_CHAR* s, STRINGLIB_CHAR* end, |
9 | Py_UCS4 u1, Py_UCS4 u2, Py_ssize_t maxcount) |
10 | { |
11 | *s = u2; |
12 | while (--maxcount && ++s != end) { |
13 | /* Find the next character to be replaced. |
14 | |
15 | If it occurs often, it is faster to scan for it using an inline |
16 | loop. If it occurs seldom, it is faster to scan for it using a |
17 | function call; the overhead of the function call is amortized |
18 | across the many characters that call covers. We start with an |
19 | inline loop and use a heuristic to determine whether to fall back |
20 | to a function call. */ |
21 | if (*s != u1) { |
22 | int attempts = 10; |
23 | /* search u1 in a dummy loop */ |
24 | while (1) { |
25 | if (++s == end) |
26 | return; |
27 | if (*s == u1) |
28 | break; |
29 | if (!--attempts) { |
30 | /* if u1 was not found for attempts iterations, |
31 | use FASTSEARCH() or memchr() */ |
32 | #if STRINGLIB_SIZEOF_CHAR == 1 |
33 | s++; |
34 | s = memchr(s, u1, end - s); |
35 | if (s == NULL) |
36 | return; |
37 | #else |
38 | Py_ssize_t i; |
39 | STRINGLIB_CHAR ch1 = (STRINGLIB_CHAR) u1; |
40 | s++; |
41 | i = FASTSEARCH(s, end - s, &ch1, 1, 0, FAST_SEARCH); |
42 | if (i < 0) |
43 | return; |
44 | s += i; |
45 | #endif |
46 | /* restart the dummy loop */ |
47 | break; |
48 | } |
49 | } |
50 | } |
51 | *s = u2; |
52 | } |
53 | } |
54 | |