static IntType add(IntType x, IntType c)
{
if(((unsigned_m() - 1) & unsigned_m()) == 0)
return (unsigned_type(x) + unsigned_type(c)) & (unsigned_m() - 1);
else if(c == 0)
return x;
else if(x < m - c)
return x + c;
else
return x - (m - c);
}
static IntType mult_add(IntType a, IntType x, IntType c)
{
if(((unsigned_m() - 1) & unsigned_m()) == 0)
return (unsigned_type(a) * unsigned_type(x) + unsigned_type(c)) & (unsigned_m() - 1);
else if(a == 0)
return c;
else if(m <= (traits::const_max-c)/a) { // i.e. a*m+c <= max
IntType supress_warnings = (m == 0);
BOOST_ASSERT(supress_warnings == 0);
return (a*x+c) % (m + supress_warnings);
} else
return add(mult(a, x), c);
}
void request::check_alignment() const
{
if (m_offset % STXXL_BLOCK_ALIGN != 0)
STXXL_ERRMSG("Offset is not aligned: modulo " <<
STXXL_BLOCK_ALIGN << " = " << m_offset % STXXL_BLOCK_ALIGN);
if (m_bytes % STXXL_BLOCK_ALIGN != 0)
STXXL_ERRMSG("Size is not a multiple of " <<
STXXL_BLOCK_ALIGN << ", = " << m_bytes % STXXL_BLOCK_ALIGN);
if (unsigned_type(m_buffer) % STXXL_BLOCK_ALIGN != 0)
STXXL_ERRMSG("Buffer is not aligned: modulo " <<
STXXL_BLOCK_ALIGN << " = " << unsigned_type(m_buffer) % STXXL_BLOCK_ALIGN <<
" (" << m_buffer << ")");
}
static IntType mult(IntType a, IntType x)
{
if(((unsigned_m() - 1) & unsigned_m()) == 0)
return unsigned_type(a) * unsigned_type(x) & (unsigned_m() - 1);
else if(a == 0)
return 0;
else if(a == 1)
return x;
else if(m <= traits::const_max/a) // i.e. a*m <= max
return mult_small(a, x);
else if(traits::is_signed && (m%a < m/a))
return mult_schrage(a, x);
else
return mult_general(a, x);
}
int utype_prior(unsigned_type ui)
{
// TBD: Implement a templated binary search for this.
int priority_bit;
unsigned_type priority_mask = unsigned_type(unsigned_type(1U) << (std::numeric_limits<unsigned_type>::digits - 1));
for(priority_bit = std::numeric_limits<unsigned_type>::digits - 1; priority_bit >= 0; --priority_bit)
{
if(unsigned_type(priority_mask & ui) != unsigned_type(0U))
{
break;
}
priority_mask >>= 1;
}
return priority_bit;
}
static IntType apply(IntType x)
{
if(((unsigned_m() - 1) & unsigned_m()) == 0)
return (unsigned_type(x)) & (unsigned_m() - 1);
else {
IntType supress_warnings = (m == 0);
BOOST_ASSERT(supress_warnings == 0);
return x % (m + supress_warnings);
}
}
