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
