github.com/cockroachdb/cockroachdb-parser@v0.23.3-0.20240213214944-911057d40c9a/pkg/util/uint128/uint128.go (about)

     1  // Copyright 2017 The Cockroach Authors.
     2  //
     3  // Use of this software is governed by the Business Source License
     4  // included in the file licenses/BSL.txt.
     5  //
     6  // As of the Change Date specified in that file, in accordance with
     7  // the Business Source License, use of this software will be governed
     8  // by the Apache License, Version 2.0, included in the file
     9  // licenses/APL.txt.
    10  
    11  package uint128
    12  
    13  import (
    14  	"encoding/binary"
    15  	"encoding/hex"
    16  
    17  	"github.com/cockroachdb/errors"
    18  )
    19  
    20  // Uint128 is a big-endian 128 bit unsigned integer which wraps two uint64s.
    21  type Uint128 struct {
    22  	Hi, Lo uint64
    23  }
    24  
    25  // GetBytes returns a big-endian byte representation.
    26  func (u Uint128) GetBytes() []byte {
    27  	buf := make([]byte, 16)
    28  	binary.BigEndian.PutUint64(buf[:8], u.Hi)
    29  	binary.BigEndian.PutUint64(buf[8:], u.Lo)
    30  	return buf
    31  }
    32  
    33  // AppendBytes appends big-endian byte representation to the
    34  // buffer and returns the buffer.
    35  func (u Uint128) AppendBytes(buf []byte) []byte {
    36  	buf = binary.BigEndian.AppendUint64(buf, u.Hi)
    37  	return binary.BigEndian.AppendUint64(buf, u.Lo)
    38  }
    39  
    40  // String returns a hexadecimal string representation.
    41  func (u Uint128) String() string {
    42  	return hex.EncodeToString(u.GetBytes())
    43  }
    44  
    45  // Equal returns whether or not the Uint128 are equivalent.
    46  func (u Uint128) Equal(o Uint128) bool {
    47  	return u.Hi == o.Hi && u.Lo == o.Lo
    48  }
    49  
    50  // Compare compares the two Uint128.
    51  func (u Uint128) Compare(o Uint128) int {
    52  	if u.Hi > o.Hi {
    53  		return 1
    54  	} else if u.Hi < o.Hi {
    55  		return -1
    56  	} else if u.Lo > o.Lo {
    57  		return 1
    58  	} else if u.Lo < o.Lo {
    59  		return -1
    60  	}
    61  	return 0
    62  }
    63  
    64  // Add returns a new Uint128 incremented by n.
    65  func (u Uint128) Add(n uint64) Uint128 {
    66  	lo := u.Lo + n
    67  	hi := u.Hi
    68  	if u.Lo > lo {
    69  		hi++
    70  	}
    71  	return Uint128{hi, lo}
    72  }
    73  
    74  // Sub returns a new Uint128 decremented by n.
    75  func (u Uint128) Sub(n uint64) Uint128 {
    76  	lo := u.Lo - n
    77  	hi := u.Hi
    78  	if u.Lo < lo {
    79  		hi--
    80  	}
    81  	return Uint128{hi, lo}
    82  }
    83  
    84  // And returns a new Uint128 that is the bitwise AND of two Uint128 values.
    85  func (u Uint128) And(o Uint128) Uint128 {
    86  	return Uint128{u.Hi & o.Hi, u.Lo & o.Lo}
    87  }
    88  
    89  // Or returns a new Uint128 that is the bitwise OR of two Uint128 values.
    90  func (u Uint128) Or(o Uint128) Uint128 {
    91  	return Uint128{u.Hi | o.Hi, u.Lo | o.Lo}
    92  }
    93  
    94  // Xor returns a new Uint128 that is the bitwise XOR of two Uint128 values.
    95  func (u Uint128) Xor(o Uint128) Uint128 {
    96  	return Uint128{u.Hi ^ o.Hi, u.Lo ^ o.Lo}
    97  }
    98  
    99  // FromBytes parses the byte slice as a 128 bit big-endian unsigned integer.
   100  // The caller is responsible for ensuring the byte slice contains 16 bytes.
   101  func FromBytes(b []byte) Uint128 {
   102  	hi := binary.BigEndian.Uint64(b[:8])
   103  	lo := binary.BigEndian.Uint64(b[8:])
   104  	return Uint128{hi, lo}
   105  }
   106  
   107  // FromString parses a hexadecimal string as a 128-bit big-endian unsigned integer.
   108  func FromString(s string) (Uint128, error) {
   109  	if len(s) > 32 {
   110  		return Uint128{}, errors.Errorf("input string %s too large for uint128", s)
   111  	}
   112  	bytes, err := hex.DecodeString(s)
   113  	if err != nil {
   114  		return Uint128{}, errors.Wrapf(err, "could not decode %s as hex", s)
   115  	}
   116  
   117  	// Grow the byte slice if it's smaller than 16 bytes, by prepending 0s
   118  	if len(bytes) < 16 {
   119  		bytesCopy := make([]byte, 16)
   120  		copy(bytesCopy[(16-len(bytes)):], bytes)
   121  		bytes = bytesCopy
   122  	}
   123  
   124  	return FromBytes(bytes), nil
   125  }
   126  
   127  // FromInts takes in two unsigned 64-bit integers and constructs a Uint128.
   128  func FromInts(hi uint64, lo uint64) Uint128 {
   129  	return Uint128{hi, lo}
   130  }