cpython/Objects/stringlib/replace.h at main · python/cpython · GitHub

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/* stringlib: replace implementation */

#ifndef STRINGLIB_FASTSEARCH_H

#error must include "stringlib/fastsearch.h" before including this module

#endif

Py_LOCAL_INLINE(void)

STRINGLIB(replace_1char_inplace)(STRINGLIB_CHAR* s, STRINGLIB_CHAR* end,

Py_UCS4 u1, Py_UCS4 u2, Py_ssize_t maxcount)

{

*s = u2;

while (--maxcount && ++s != end) {

/* Find the next character to be replaced.

If it occurs often, it is faster to scan for it using an inline

loop. If it occurs seldom, it is faster to scan for it using a

function call; the overhead of the function call is amortized

across the many characters that call covers. We start with an

inline loop and use a heuristic to determine whether to fall back

to a function call. */

if (*s != u1) {

int attempts = 10;

/* search u1 in a dummy loop */

while (1) {

if (++s == end)

return;

if (*s == u1)

break;

if (!--attempts) {

/* if u1 was not found for attempts iterations,

use FASTSEARCH() or memchr() */

#ifdef STRINGLIB_FAST_MEMCHR

s++;

s = STRINGLIB_FAST_MEMCHR(s, u1, end - s);

if (s == NULL)

return;

#else

Py_ssize_t i;

STRINGLIB_CHAR ch1 = (STRINGLIB_CHAR) u1;

s++;

i = FASTSEARCH(s, end - s, &ch1, 1, 0, FAST_SEARCH);

if (i < 0)

return;

s += i;

#endif

/* restart the dummy loop */

break;

}

*s = u2;

}

cpython/Objects/stringlib/replace.h at main · python/cpython · GitHub

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cpython/Objects/stringlib/replace.h at main · python/cpython · GitHub

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