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Vectorize altchars #1

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Vectorize altchars #1

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c4fb540
Add altchars to the benchmark.
TkTech Oct 17, 2026
1b6c758
Store both bytes, allowing GCC to vectorize it.
TkTech Oct 17, 2026
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1 change: 1 addition & 0 deletions bench.py
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
# name -> (function name, keyword arguments, input preparation)
OPERATIONS = {
"b64encode": ("b64encode", {}, lambda raw: raw),
"b64encode(altchars)": ("b64encode", {"altchars": b"*!"}, lambda raw: raw),
"b64decode": ("b64decode", {}, base64.b64encode),
"b64decode(validate=True)": ("b64decode", {"validate": True}, base64.b64encode),
"urlsafe_b64encode": ("urlsafe_b64encode", {}, lambda raw: raw),
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10 changes: 5 additions & 5 deletions src/fastpybase64.cpp
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Expand Up @@ -215,12 +215,12 @@ PyObject *encode_with_altchars(const InputView &input, const char altchars[2]) {
}
char *out = PyBytes_AS_STRING(result);
Py_ssize_t length = PyBytes_GET_SIZE(result);
const char plus = altchars[0];
const char slash = altchars[1];
// Store every byte so the compiler can vectorize the substitution.
for (Py_ssize_t i = 0; i < length; i++) {
if (out[i] == '+') {
out[i] = altchars[0];
} else if (out[i] == '/') {
out[i] = altchars[1];
}
const char c = out[i];
out[i] = c == '+' ? plus : (c == '/' ? slash : c);
}
return result;
}
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