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Speed up string-lessp further

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* src/fns.c (Fstring_lessp): Use the memcmp fast path for ASCII-only
multibyte strings as well.  Specialise loops on argument
multibyteness.
This commit is contained in:
Mattias Engdegård 2022-09-30 13:59:45 +02:00
parent b858acde25
commit 123506f9ca
1 changed files with 43 additions and 13 deletions
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56
src/fns.c
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@ -449,25 +449,55 @@ Symbols are also allowed; their print names are used instead. */)
CHECK_STRING (string2);
ptrdiff_t n = min (SCHARS (string1), SCHARS (string2));
if (!STRING_MULTIBYTE (string1) && !STRING_MULTIBYTE (string2))
if ((!STRING_MULTIBYTE (string1) || SCHARS (string1) == SBYTES (string1))
&& (!STRING_MULTIBYTE (string2) || SCHARS (string2) == SBYTES (string2)))
{
/* Both arguments are unibyte (hot path). */
/* Each argument is either unibyte or all-ASCII multibyte:
we can compare bytewise.
(Arbitrary multibyte strings cannot be compared bytewise because
that would give a different order for raw bytes 80..FF.) */
int d = memcmp (SSDATA (string1), SSDATA (string2), n);
return d < 0 || (d == 0 && n < SCHARS (string2)) ? Qt : Qnil;
}
ptrdiff_t i1 = 0, i1_byte = 0, i2 = 0, i2_byte = 0;
while (i1 < n)
else if (STRING_MULTIBYTE (string1) && STRING_MULTIBYTE (string2))
{
/* When we find a mismatch, we must compare the
characters, not just the bytes. */
int c1 = fetch_string_char_advance (string1, &i1, &i1_byte);
int c2 = fetch_string_char_advance (string2, &i2, &i2_byte);
if (c1 != c2)
return c1 < c2 ? Qt : Qnil;
ptrdiff_t i1 = 0, i1_byte = 0, i2 = 0, i2_byte = 0;
while (i1 < n)
{
int c1 = fetch_string_char_advance_no_check (string1, &i1, &i1_byte);
int c2 = fetch_string_char_advance_no_check (string2, &i2, &i2_byte);
if (c1 != c2)
return c1 < c2 ? Qt : Qnil;
}
return i1 < SCHARS (string2) ? Qt : Qnil;
}
else if (STRING_MULTIBYTE (string1))
{
/* string1 multibyte, string2 unibyte */
ptrdiff_t i1 = 0, i1_byte = 0, i2 = 0;
while (i1 < n)
{
int c1 = fetch_string_char_advance_no_check (string1, &i1, &i1_byte);
int c2 = SREF (string2, i2++);
if (c1 != c2)
return c1 < c2 ? Qt : Qnil;
}
return i1 < SCHARS (string2) ? Qt : Qnil;
}
else
{
/* string1 unibyte, string2 multibyte */
ptrdiff_t i1 = 0, i2 = 0, i2_byte = 0;
while (i1 < n)
{
int c1 = SREF (string1, i1++);
int c2 = fetch_string_char_advance_no_check (string2, &i2, &i2_byte);
if (c1 != c2)
return c1 < c2 ? Qt : Qnil;
}
return i1 < SCHARS (string2) ? Qt : Qnil;
}
return i1 < SCHARS (string2) ? Qt : Qnil;
}
DEFUN ("string-version-lessp", Fstring_version_lessp,