package dh

import (
	"math/big"
)

const (
	// QSizeMinimum Specifies the number of the most significant bit (0 to M).
	// WARNING: internally, usually 1 to N.
	QSizeMinimum = 511

	// Prime sieving constants
	// Assuming 8 bit bytes and 32 bit words.
	ShiftBit      = 3
	ShiftByte     = 2
	ShiftWord     = ShiftBit + ShiftByte
	ShiftMegabyte = 20
	ShiftMegaWord = ShiftMegabyte - ShiftBit

	// Memory limits.
	// LargeMinimum is 8 megabytes
	LargeMinimum = uint32(8) // Originally an 8UL in moduli.c
	// LargeMaximum is 127MB.
	LargeMaximum = uint32(127)
	// The largest sieve prime has to be < 2**32 on 32-bit systems.
	SmallMaximum = uint32(0xffffffff) // 4294967295
	// Can sieve all primes less than 2**32, as 65537**2 > 2**32-1.
	TinyNumber = uint32(1) << 16
	// Ensure enough bit space for testing 2*q.
	TestMaximum = uint32(1) << 16
	TestMinimum = QSizeMinimum + 1 // (uint32(1) << (ShiftWord - TestPower))
	TestPower   = 3                // 2**n, n < ShiftWord
	// Minimum number of primality tests to perform
	TrialMinimum = 4
)

type (

	/*
		Sieving data (XXX - move to struct)
	*/

	// sieve 2**16
	TinySieve *uint32
	tinybits  uint32

	// sieve 2**30 in 2**16 parts
	SmallSieve *uint32
	smallbits  uint32
	smallbase  uint32

	// sieve relative to the initial value
	LargeSieve   *uint32
	largewords   uint32
	largetries   uint32
	largenumbers uint32
	largebits    uint32 // Megabytes..
	largememory  uint32 // ""

	largebase big.Int
)