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Add a count argument to count_whitespace

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This commit is contained in:
Peter Dimov
2020-03-27 21:41:05 +02:00
committed by Vinnie Falco
parent 0360505b75
commit edcafb3f5d
2 changed files with 61 additions and 60 deletions
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84
include/boost/json/detail/sse2.hpp
View File

@@ -207,59 +207,81 @@ inline uint64_t parse_unsigned( uint64_t r, char const * p, std::size_t n ) noex
#ifdef BOOST_JSON_USE_SSE2
// assumes p..p+15
inline std::size_t count_whitespace( char const * p )
inline std::size_t count_whitespace( char const * p, std::size_t n ) noexcept
{
// if( static_cast<unsigned char>( p[0] ) > 0x20 ) return 0;
if( n == 0 )
{
return 0;
}
if( static_cast<unsigned char>( *p ) > 0x20 )
{
return 0;
}
char const * p0 = p;
__m128i const q1 = _mm_set1_epi8( ' ' );
__m128i const q2 = _mm_set1_epi8( '\n' );
__m128i const q3 = _mm_set1_epi8( '\r' );
__m128i const q4 = _mm_set1_epi8( '\t' );
__m128i v = _mm_loadu_si128( (__m128i const*)p );
__m128i w = _mm_cmpeq_epi8( v, q1 );
w = _mm_or_si128( w, _mm_cmpeq_epi8( v, q2 ) );
w = _mm_or_si128( w, _mm_cmpeq_epi8( v, q3 ) );
w = _mm_or_si128( w, _mm_cmpeq_epi8( v, q4 ) );
int m = _mm_movemask_epi8( w ) ^ 0xFFFF;
std::size_t n;
if( m == 0 )
{
n = 16;
}
else
while( n >= 16 )
{
__m128i v = _mm_loadu_si128( (__m128i const*)p );
__m128i w = _mm_cmpeq_epi8( v, q1 );
w = _mm_or_si128( w, _mm_cmpeq_epi8( v, q2 ) );
w = _mm_or_si128( w, _mm_cmpeq_epi8( v, q3 ) );
w = _mm_or_si128( w, _mm_cmpeq_epi8( v, q4 ) );
int m = _mm_movemask_epi8( w ) ^ 0xFFFF;
if( m != 0 )
{
#if defined(__GNUC__) || defined(__clang__)
n = __builtin_ffs( m ) - 1;
std::size_t n = __builtin_ffs( m ) - 1;
#else
unsigned long index;
_BitScanForward( &index, m );
n = index;
unsigned long index;
_BitScanForward( &index, m );
std::size_t n = index;
#endif
p += n;
return p - p0;
}
p += 16;
n -= 16;
}
return n;
while( n > 0 )
{
if( *p != ' ' && *p != '\t' && *p != '\r' && *p != '\n' )
{
return p - p0;
}
++p;
--n;
}
return p - p0;
}
#else
// assumes p..p+15
inline std::size_t count_whitespace( char const * p )
inline std::size_t count_whitespace( char const * p, std::size_t n ) noexcept
{
std::size_t n = 0;
std::size_t i = 0;
for( ; n < 16; ++p, ++n )
for( ; i < n; ++p, ++i )
{
char const c = *p;
if( c != ' ' && c != '\n' && c != '\r' && c != '\t' ) break;
}
return n;
return i;
}
#endif
@@ -269,7 +291,7 @@ inline std::size_t count_whitespace( char const * p )
#ifdef BOOST_JSON_USE_SSE2
// assumes p..p+15
inline std::size_t count_leading( char const * p, char ch )
inline std::size_t count_leading( char const * p, char ch ) noexcept
{
__m128i const q1 = _mm_set1_epi8( ch );
@@ -302,7 +324,7 @@ inline std::size_t count_leading( char const * p, char ch )
#else
// assumes p..p+15
inline std::size_t count_leading( char const * p, char ch )
inline std::size_t count_leading( char const * p, char ch ) noexcept
{
std::size_t n = 0;

37
include/boost/json/impl/basic_parser.ipp
View File

@@ -299,37 +299,16 @@ void
basic_parser::
parse_white(const_stream& cs)
{
while( BOOST_JSON_LIKELY(cs) )
char const * p = cs.data();
std::size_t n = cs.remain();
std::size_t n2 = detail::count_whitespace( p, n );
cs.skip( n2 );
if( n2 == n )
{
char const ch = *cs;
if( static_cast<unsigned char>( ch ) > 0x20 ) return;
if( ch == '\n' || ch == '\r' )
{
++cs;
continue;
}
if( ch != ' ' && ch != '\t' )
{
return;
}
++cs;
while( cs.remain() >= 16 )
{
if( static_cast<unsigned char>( *cs ) > 0x20 ) return;
std::size_t n = detail::count_leading( cs.data(), ch );
cs.skip( n );
if( n < 16 ) break;
}
ec_ = error::incomplete;
}
ec_ = error::incomplete;
}
void