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Issue #15026: utf-16 encoding is now significantly faster (up to 10x).

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Patch by Serhiy Storchaka.
This commit is contained in:
Antoine Pitrou 2012-06-15 22:15:23 +02:00
parent 3049f1243e
commit 27f6a3b0bf
4 changed files with 102 additions and 49 deletions
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64
Objects/stringlib/codecs.h
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@ -562,4 +562,68 @@ IllegalSurrogate:
#undef STRIPPED_MASK
#undef SWAB
#undef LONG_PTR_MASK
Py_LOCAL_INLINE(void)
STRINGLIB(utf16_encode)(unsigned short *out,
const STRINGLIB_CHAR *in,
Py_ssize_t len,
int native_ordering)
{
const STRINGLIB_CHAR *end = in + len;
#if STRINGLIB_SIZEOF_CHAR == 1
# define SWAB2(CH) ((CH) << 8)
#else
# define SWAB2(CH) (((CH) << 8) | ((CH) >> 8))
#endif
#if STRINGLIB_MAX_CHAR < 0x10000
if (native_ordering) {
# if STRINGLIB_SIZEOF_CHAR == 2
Py_MEMCPY(out, in, 2 * len);
# else
_PyUnicode_CONVERT_BYTES(STRINGLIB_CHAR, unsigned short, in, end, out);
# endif
} else {
const STRINGLIB_CHAR *unrolled_end = in + (len & ~ (Py_ssize_t) 3);
while (in < unrolled_end) {
out[0] = SWAB2(in[0]);
out[1] = SWAB2(in[1]);
out[2] = SWAB2(in[2]);
out[3] = SWAB2(in[3]);
in += 4; out += 4;
}
while (in < end) {
*out++ = SWAB2(*in);
++in;
}
}
#else
if (native_ordering) {
while (in < end) {
Py_UCS4 ch = *in++;
if (ch < 0x10000)
*out++ = ch;
else {
out[0] = Py_UNICODE_HIGH_SURROGATE(ch);
out[1] = Py_UNICODE_LOW_SURROGATE(ch);
out += 2;
}
}
} else {
while (in < end) {
Py_UCS4 ch = *in++;
if (ch < 0x10000)
*out++ = SWAB2((Py_UCS2)ch);
else {
Py_UCS2 ch1 = Py_UNICODE_HIGH_SURROGATE(ch);
Py_UCS2 ch2 = Py_UNICODE_LOW_SURROGATE(ch);
out[0] = SWAB2(ch1);
out[1] = SWAB2(ch2);
out += 2;
}
}
}
#endif
#undef SWAB2
}
#endif /* STRINGLIB_IS_UNICODE */