wchar_t * __cdecl wcschr (
const wchar_t * str,
wchar_t ch
)
{
if (__isa_available < __ISA_AVAILABLE_SSE2)
{
while (*str && *str != ch)
str++;
// If the character is a match return pointer, otherwise
// it must be the terminating zero and return NULL.
return (*str == ch) ? (wchar_t *)str : NULL;
}
else
{
__m128i match, characters, temp;
unsigned mask;
unsigned long offset;
// Build match pattern with target character in every position.
match = _mm_cvtsi32_si128(ch);
match = _mm_shufflelo_epi16(match, 0);
match = _mm_shuffle_epi32(match, 0);
for (;;)
{
// If the next XMMWORD does not overlap a page boundary check
// it for match of character or zero.
if (XMM_PAGE_SAFE(str))
{
// Check for match with either the search or zero character.
// There may be more than one match, but only the first is
// significant.
characters = _mm_loadu_si128((__m128i*)str);
temp = _mm_xor_si128(temp, temp);
temp = _mm_cmpeq_epi16(temp, characters);
characters = _mm_cmpeq_epi16(characters, match);
temp = _mm_or_si128(temp, characters);
mask = _mm_movemask_epi8(temp);
// If one or more matches was found, get the position of
// the first one. If that character is the same as the
// search character return the pointer to it, otherwise
// it must be the terminating zero so return NULL.
if (mask != 0)
{
_BitScanForward(&offset, mask);
str = (wchar_t *)(offset + (intptr_t)str);
return (*str == ch) ? (wchar_t *)str : NULL;
}
// No match found in this XMMWORD so skip to next.
str += XMM_CHARS;
}
else
{
// If it is not safe to check an entire XMMWORD, check
// a single character and try again.
if (*str == ch) return (wchar_t *)str;
if (*str == 0) return NULL;
// No match so skip to next characcter.
++str;
}
}
}
}
wchar_t * __cdecl wcsstr (
const wchar_t * wcs1,
const wchar_t * wcs2
)
{
const wchar_t *stmp1, *stmp2;
__m128i zero, pattern, characters1, characters2;
// An empty search string matches everything.
if (0 == *wcs2)
return (wchar_t *)wcs1;
if (__isa_available > __ISA_AVAILABLE_SSE2)
{
wchar_t c;
unsigned i;
// Load XMM with first characters of wcs2.
if (XMM_PAGE_SAFE(wcs2))
{
pattern = _mm_loadu_si128((__m128i*)wcs2);
}
else
{
pattern = _mm_xor_si128(pattern, pattern);
c = *(stmp2 = wcs2);
for (i = 0; i < XMM_CHARS; ++i)
{
pattern = _mm_srli_si128(pattern, sizeof(wchar_t));
pattern = _mm_insert_epi16(pattern, c, (XMM_CHARS-1));
if (0 != c) c = *++stmp2;
}
}
for(;;)
{
// Check for partial match, if none step forward and continue.
if (XMM_PAGE_SAFE(wcs1))
{
characters1 = _mm_loadu_si128((__m128i*)wcs1);
// If no potential match or end found, try next XMMWORD.
if (_mm_cmpistra(pattern, characters1, f_srch_sub))
{
wcs1 += XMM_CHARS;
continue;
}
// If end found there was no match.
else if (!_mm_cmpistrc(pattern, characters1, f_srch_sub))
{
return NULL;
}
// Get position of potential match.
wcs1 += _mm_cmpistri(pattern, characters1, f_srch_sub);
}
else
{
// If end of string found there was no match.
if (0 == *wcs1)
{
return NULL;
}
// If current character doesn't match first character
// of search string try next character.
if (*wcs1 != *wcs2)
{
++wcs1;
continue;
}
}
// Potential match, compare to check for full match.
stmp1 = wcs1;
stmp2 = wcs2;
for (;;)
{
// If next XMMWORD is page-safe for each string
// do a XMMWORD comparison.
if (XMM_PAGE_SAFE(stmp1) && XMM_PAGE_SAFE(stmp2))
{
characters1 = _mm_loadu_si128((__m128i*)stmp1);
characters2 = _mm_loadu_si128((__m128i*)stmp2);
// If unequal then no match found.
if (!_mm_cmpistro(characters2, characters1, f_srch_sub))
{
break;
}
// If end of search string then match found.
else if (_mm_cmpistrs(characters2, characters1, f_srch_sub))
{
return (wchar_t *)wcs1;
}
stmp1 += XMM_CHARS;
stmp2 += XMM_CHARS;
continue;
}
// Compare next character.
else
{
// If end of search string then match found.
if (0 == *stmp2)
{
return (wchar_t *)wcs1;
}
// If unequal then no match found.
if (*stmp1 != *stmp2)
{
break;
}
// Character matched - try next character.
++stmp1;
++stmp2;
}
}
// Match not found at current position, try next.
++wcs1;
}
}
else if (__isa_available == __ISA_AVAILABLE_SSE2)
{
unsigned offset, mask;
// Build search pattern and zero pattern. Search pattern is
// XMMWORD with the initial character of the search string
// in every position. Zero pattern has a zero termination
// character in every position.
pattern = _mm_cvtsi32_si128(wcs2[0]);
pattern = _mm_shufflelo_epi16(pattern, 0);
pattern = _mm_shuffle_epi32(pattern, 0);
zero = _mm_xor_si128(zero, zero);
// Main loop for searching wcs1.
for (;;)
{
// If XMM check is safe advance wcs1 to the next
// possible match or end.
if (XMM_PAGE_SAFE(wcs1))
{
characters1 = _mm_loadu_si128((__m128i*)wcs1);
characters2 = _mm_cmpeq_epi16(characters1, zero);
characters1 = _mm_cmpeq_epi16(characters1, pattern);
characters1 = _mm_or_si128(characters1, characters2);
mask = _mm_movemask_epi8(characters1);
// If no character match or end found try next XMMWORD.
if (0 == mask)
{
wcs1 += XMM_CHARS;
continue;
}
// Advance wcs1 pointer to next possible match or end.
_BitScanForward(&offset, mask);
wcs1 += (offset/sizeof(wchar_t));
}
// If at the end of wcs1, then no match found.
if (0 == wcs1[0]) return NULL;
// If a first-character match is found compare
// strings to look for match.
if (wcs2[0] == wcs1[0])
{
stmp1 = wcs1;
stmp2 = wcs2;
for (;;)
{
// If aligned as specified advance to next
// possible difference or wcs2 end.
if (XMM_PAGE_SAFE(stmp2) && XMM_PAGE_SAFE(stmp1))
{
characters1 = _mm_loadu_si128((__m128i*)stmp1);
characters2 = _mm_loadu_si128((__m128i*)stmp2);
characters1 = _mm_cmpeq_epi16(characters1, characters2);
characters2 = _mm_cmpeq_epi16(characters2, zero);
characters1 = _mm_cmpeq_epi16(characters1, zero);
characters1 = _mm_or_si128(characters1, characters2);
mask = _mm_movemask_epi8(characters1);
// If mask is zero there is no difference and
// wcs2 does not end in this XMMWORD. Continue
// with next XMMWORD.
if (0 == mask)
{
stmp1 += XMM_CHARS;
stmp2 += XMM_CHARS;
continue;
}
// Advance string pointers to next significant
// character.
_BitScanForward(&offset, mask);
stmp1 += (offset/sizeof(wchar_t));
stmp2 += (offset/sizeof(wchar_t));
}
// If we've reached the end of wcs2 then a match
// has been found.
if (0 == stmp2[0]) return (wchar_t *)wcs1;
// If we've reached a difference then no match
// was found.
if (stmp1[0] != stmp2[0]) break;
// Otherwise advance to next character and try
// again.
++stmp1;
++stmp2;
}
}
// Current character wasn't a match, try next character.
++wcs1;
}
}
else
{
const wchar_t *cp = wcs1;
const wchar_t *s1, *s2;
while (*cp)
{
s1 = cp;
s2 = wcs2;
while ( *s1 && *s2 && !(*s1-*s2) )
s1++, s2++;
if (!*s2)
return (wchar_t *) cp;
cp++;
}
return NULL;
}
}
