github.com/JimmyHuang454/JLS-go@v0.0.0-20230831150107-90d536585ba0/boring/bbig/big.go (about)

     1  // Copyright 2022 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package bbig
     6  
     7  import (
     8  	"crypto/internal/boring"
     9  	"math/big"
    10  	"unsafe"
    11  )
    12  
    13  func Enc(b *big.Int) boring.BigInt {
    14  	if b == nil {
    15  		return nil
    16  	}
    17  	x := b.Bits()
    18  	if len(x) == 0 {
    19  		return boring.BigInt{}
    20  	}
    21  	return unsafe.Slice((*uint)(&x[0]), len(x))
    22  }
    23  
    24  func Dec(b boring.BigInt) *big.Int {
    25  	if b == nil {
    26  		return nil
    27  	}
    28  	if len(b) == 0 {
    29  		return new(big.Int)
    30  	}
    31  	x := unsafe.Slice((*big.Word)(&b[0]), len(b))
    32  	return new(big.Int).SetBits(x)
    33  }