// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package subtle

import (
	
	
)

// ConstantTimeCompare returns 1 if the two slices, x and y, have equal contents
// and 0 otherwise. The time taken is a function of the length of the slices and
// is independent of the contents. If the lengths of x and y do not match it
// returns 0 immediately.
func (,  []byte) int {
	if len() != len() {
		return 0
	}

	var  byte

	for  := 0;  < len(); ++ {
		 |= [] ^ []
	}

	return ConstantTimeByteEq(, 0)
}

// ConstantTimeLessOrEqBytes returns 1 if x <= y and 0 otherwise. The comparison
// is lexigraphical, or big-endian. The time taken is a function of the length of
// the slices and is independent of the contents. If the lengths of x and y do not
// match it returns 0 immediately.
func (,  []byte) int {
	if len() != len() {
		return 0
	}

	// Do a constant time subtraction chain y - x.
	// If there is no borrow at the end, then x <= y.
	var  uint64
	for len() > 8 {
		 := byteorder.BEUint64([len()-8:])
		 := byteorder.BEUint64([len()-8:])
		_,  = bits.Sub64(, , )
		 = [:len()-8]
		 = [:len()-8]
	}
	if len() > 0 {
		 := make([]byte, 8)
		 := make([]byte, 8)
		copy([8-len():], )
		copy([8-len():], )
		 := byteorder.BEUint64()
		 := byteorder.BEUint64()
		_,  = bits.Sub64(, , )
	}
	return int( ^ 1)
}

// ConstantTimeSelect returns x if v == 1 and y if v == 0.
// Its behavior is undefined if v takes any other value.
func (, ,  int) int { return ^(-1)& | (-1)& }

// ConstantTimeByteEq returns 1 if x == y and 0 otherwise.
func (,  uint8) int {
	return int((uint32(^) - 1) >> 31)
}

// ConstantTimeEq returns 1 if x == y and 0 otherwise.
func (,  int32) int {
	return int((uint64(uint32(^)) - 1) >> 63)
}

// ConstantTimeCopy copies the contents of y into x (a slice of equal length)
// if v == 1. If v == 0, x is left unchanged. Its behavior is undefined if v
// takes any other value.
func ( int, ,  []byte) {
	if len() != len() {
		panic("subtle: slices have different lengths")
	}

	 := byte( - 1)
	 := byte(^( - 1))
	for  := 0;  < len(); ++ {
		[] = []& | []&
	}
}

// ConstantTimeLessOrEq returns 1 if x <= y and 0 otherwise.
// Its behavior is undefined if x or y are negative or > 2**31 - 1.
func (,  int) int {
	 := int32()
	 := int32()
	return int((( -  - 1) >> 31) & 1)
}