void test() {
char *goodsequences[] = {"a", "\xc3\xb1", "\xe2\x82\xa1", "\xf0\x90\x8c\xbc"};
char *badsequences[] = {
"\xc3\x28", "\xa0\xa1", "\xe2\x28\xa1", "\xe2\x82\x28",
"\xf0\x28\x8c\xbc", "\xf0\x90\x28\xbc", "\xf0\x28\x8c\x28"};
for (size_t i = 0; i < 4; i++) {
size_t len = strlen(goodsequences[i]);
assert(validate_utf8(goodsequences[i], len));
}
for (size_t i = 0; i < 7; i++) {
size_t len = strlen(badsequences[i]);
assert(!validate_utf8(badsequences[i], len));
}
}
void demo(size_t N) {
printf("string size = %zu \n", N);
char *data = (char *)malloc(N);
bool expected = true; // it is all ascii?
int repeat = 5;
printf("We are feeding ascii so it is always going to be ok.\n");
BEST_TIME(is_ascii(data, N), expected,populate(data,N) , repeat, N, true);
BEST_TIME(validate_utf8(data, N), expected,populate(data,N) , repeat, N, true);
BEST_TIME(validate_utf8_branchless(data, N), expected,populate(data,N) , repeat, N, true);
BEST_TIME(validate_utf8_double(data, N), expected,populate(data,N) , repeat, N, true);
BEST_TIME(shiftless_validate_utf8(data, N), expected,populate(data,N) , repeat, N, true);
BEST_TIME(shiftless_validate_utf8_branchless(data, N), expected,populate(data,N) , repeat, N, true);
BEST_TIME(shiftless_validate_utf8_double(data, N), expected,populate(data,N) , repeat, N, true);
BEST_TIME(validate_utf8_sse_nocheating(data, N), expected,populate(data,N) , repeat, N, true);
BEST_TIME(validate_utf8_sse(data, N), expected,populate(data,N) , repeat, N, true);
free(data);
}
}bool validate_utf8_sse(const char *src, size_t len) {
const char *end = src + len;
while (src + 16 < end) {
__m128i chunk = _mm_loadu_si128((const __m128i *)(src));
int asciiMask = _mm_movemask_epi8(chunk);
if (!asciiMask) {
src += 16;
continue;
}
__m128i chunk_signed = _mm_add_epi8(chunk, _mm_set1_epi8(0x80));
__m128i cond2 =
_mm_cmplt_epi8(_mm_set1_epi8(0xc2 - 1 - 0x80), chunk_signed);
__m128i state = _mm_set1_epi8((char)(0x0 | 0x80));
state = _mm_blendv_epi8(state, _mm_set1_epi8((char)(0x2 | 0xc0)), cond2);
__m128i cond3 =
_mm_cmplt_epi8(_mm_set1_epi8(0xe0 - 1 - 0x80), chunk_signed);
state = _mm_blendv_epi8(state, _mm_set1_epi8((char)(0x3 | 0xe0)), cond3);
__m128i mask3 = _mm_slli_si128(cond3, 1);
__m128i cond4 =
_mm_cmplt_epi8(_mm_set1_epi8(0xf0 - 1 - 0x80), chunk_signed);
// Fall back to the scalar processing
if (_mm_movemask_epi8(cond4)) {
break;
}
__m128i count = _mm_and_si128(state, _mm_set1_epi8(0x7));
__m128i count_sub1 = _mm_subs_epu8(count, _mm_set1_epi8(0x1));
__m128i counts = _mm_add_epi8(count, _mm_slli_si128(count_sub1, 1));
__m128i shifts = count_sub1;
shifts = _mm_add_epi8(shifts, _mm_slli_si128(shifts, 1));
counts = _mm_add_epi8(
counts, _mm_slli_si128(_mm_subs_epu8(counts, _mm_set1_epi8(0x2)), 2));
shifts = _mm_add_epi8(shifts, _mm_slli_si128(shifts, 2));
if (asciiMask ^ _mm_movemask_epi8(_mm_cmpgt_epi8(counts, _mm_set1_epi8(0))))
return false; // error
shifts = _mm_add_epi8(shifts, _mm_slli_si128(shifts, 4));
if (_mm_movemask_epi8(_mm_cmpgt_epi8(
_mm_sub_epi8(_mm_slli_si128(counts, 1), counts), _mm_set1_epi8(1))))
return false; // error
shifts = _mm_add_epi8(shifts, _mm_slli_si128(shifts, 8));
__m128i mask = _mm_and_si128(state, _mm_set1_epi8(0xf8));
shifts =
_mm_and_si128(shifts, _mm_cmplt_epi8(counts, _mm_set1_epi8(2))); // <=1
chunk =
_mm_andnot_si128(mask, chunk); // from now on, we only have usefull bits
shifts = _mm_blendv_epi8(shifts, _mm_srli_si128(shifts, 1),
_mm_srli_si128(_mm_slli_epi16(shifts, 7), 1));
__m128i chunk_right = _mm_slli_si128(chunk, 1);
__m128i chunk_low = _mm_blendv_epi8(
chunk,
_mm_or_si128(chunk, _mm_and_si128(_mm_slli_epi16(chunk_right, 6),
_mm_set1_epi8(0xc0))),
_mm_cmpeq_epi8(counts, _mm_set1_epi8(1)));
__m128i chunk_high =
_mm_and_si128(chunk, _mm_cmpeq_epi8(counts, _mm_set1_epi8(2)));
shifts = _mm_blendv_epi8(shifts, _mm_srli_si128(shifts, 2),
_mm_srli_si128(_mm_slli_epi16(shifts, 6), 2));
chunk_high = _mm_srli_epi32(chunk_high, 2);
shifts = _mm_blendv_epi8(shifts, _mm_srli_si128(shifts, 4),
_mm_srli_si128(_mm_slli_epi16(shifts, 5), 4));
chunk_high = _mm_or_si128(
chunk_high, _mm_and_si128(_mm_and_si128(_mm_slli_epi32(chunk_right, 4),
_mm_set1_epi8(0xf0)),
mask3));
int c = _mm_extract_epi16(counts, 7);
int source_advance = !(c & 0x0200) ? 16 : !(c & 0x02) ? 15 : 14;
__m128i high_bits = _mm_and_si128(chunk_high, _mm_set1_epi8(0xf8));
if (!_mm_testz_si128(
mask3,
_mm_or_si128(_mm_cmpeq_epi8(high_bits, _mm_set1_epi8(0x00)),
_mm_cmpeq_epi8(high_bits, _mm_set1_epi8(0xd8)))))
return false;
shifts = _mm_blendv_epi8(shifts, _mm_srli_si128(shifts, 8),
_mm_srli_si128(_mm_slli_epi16(shifts, 4), 8));
chunk_high = _mm_slli_si128(chunk_high, 1);
__m128i shuf =
_mm_add_epi8(shifts, _mm_set_epi8(15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5,
4, 3, 2, 1, 0));
chunk_low = _mm_shuffle_epi8(chunk_low, shuf);
chunk_high = _mm_shuffle_epi8(chunk_high, shuf);
__m128i utf16_low = _mm_unpacklo_epi8(chunk_low, chunk_high);
__m128i utf16_high = _mm_unpackhi_epi8(chunk_low, chunk_high);
if (_mm_cmpestrc(_mm_cvtsi64_si128(0xfdeffdd0fffffffe), 4, utf16_high, 8,
_SIDD_UWORD_OPS | _SIDD_CMP_RANGES) |
_mm_cmpestrc(_mm_cvtsi64_si128(0xfdeffdd0fffffffe), 4, utf16_low, 8,
_SIDD_UWORD_OPS | _SIDD_CMP_RANGES)) {
return false;
}
src += source_advance;
}
return validate_utf8(src, end - src);
}
string::size_type string::find_last_not_of<xmlChar>(const xmlChar * s, size_type pos) const {
validate_utf8(s+pos, npos);
return find_last_not_of(_Convert<xmlChar>::toUTF8(s), pos);
}
string::size_type string::find_first_not_of<char>(const char * s, size_type pos, size_type n) const {
validate_utf8(s+pos, npos);
return find_first_not_of(_Convert<char>::toUTF8(s), pos);
}
void string::validate_utf8(const xmlChar *s, size_type sz) const
{
validate_utf8(reinterpret_cast<const char*>(s), sz == npos ? xmlStrlen(s) : sz);
}
