github.com/Schaudge/grailbase@v0.0.0-20240223061707-44c758a471c0/writehash/writehash.go (about)

     1  // Copyright 2019 GRAIL, Inc. All rights reserved.
     2  // Use of this source code is governed by the Apache 2.0
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package writehash provides a set of utility functions to hash
     6  // common types into hashes.
     7  package writehash
     8  
     9  import (
    10  	"encoding/binary"
    11  	"fmt"
    12  	"hash"
    13  	"io"
    14  	"math"
    15  )
    16  
    17  func must(n int, err error) {
    18  	if err != nil {
    19  		panic(fmt.Sprintf("writehash: hash.Write returned unexpected error: %v", err))
    20  	}
    21  }
    22  
    23  // String encodes the string s into writer w.
    24  func String(h hash.Hash, s string) {
    25  	must(io.WriteString(h, s))
    26  }
    27  
    28  // Int encodes the integer v into writer w.
    29  func Int(h hash.Hash, v int) {
    30  	Uint64(h, uint64(v))
    31  }
    32  
    33  // Int16 encodes the 16-bit integer v into writer w.
    34  func Int16(h hash.Hash, v int) {
    35  	Uint16(h, uint16(v))
    36  }
    37  
    38  // Int32 encodes the 32-bit integer v into writer w.
    39  func Int32(h hash.Hash, v int32) {
    40  	Uint32(h, uint32(v))
    41  }
    42  
    43  // Int64 encodes the 64-bit integer v into writer w.
    44  func Int64(h hash.Hash, v int64) {
    45  	Uint64(h, uint64(v))
    46  }
    47  
    48  // Uint encodes the unsigned integer v into writer w.
    49  func Uint(h hash.Hash, v uint) {
    50  	Uint64(h, uint64(v))
    51  }
    52  
    53  // Uint16 encodes the unsigned 16-bit integer v into writer w.
    54  func Uint16(h hash.Hash, v uint16) {
    55  	var buf [2]byte
    56  	binary.LittleEndian.PutUint16(buf[:], v)
    57  	must(h.Write(buf[:]))
    58  }
    59  
    60  // Uint32 encodes the unsigned 32-bit integer v into writer w.
    61  func Uint32(h hash.Hash, v uint32) {
    62  	var buf [4]byte
    63  	binary.LittleEndian.PutUint32(buf[:], v)
    64  	must(h.Write(buf[:]))
    65  }
    66  
    67  // Uint64 encodes the unsigned 64-bit integer v into writer w.
    68  func Uint64(h hash.Hash, v uint64) {
    69  	var buf [8]byte
    70  	binary.LittleEndian.PutUint64(buf[:], v)
    71  	must(h.Write(buf[:]))
    72  }
    73  
    74  // Float32 encodes the 32-bit floating point number v into writer w.
    75  func Float32(h hash.Hash, v float32) {
    76  	Uint32(h, math.Float32bits(v))
    77  }
    78  
    79  // Float64 encodes the 64-bit floating point number v into writer w.
    80  func Float64(h hash.Hash, v float64) {
    81  	Uint64(h, math.Float64bits(v))
    82  }
    83  
    84  // Bool encodes the boolean v into writer w.
    85  func Bool(h hash.Hash, v bool) {
    86  	if v {
    87  		Byte(h, 1)
    88  	} else {
    89  		Byte(h, 0)
    90  	}
    91  }
    92  
    93  // Byte writes the byte b into writer w.
    94  func Byte(h hash.Hash, b byte) {
    95  	if w, ok := h.(io.ByteWriter); ok {
    96  		must(0, w.WriteByte(b))
    97  		return
    98  	}
    99  	must(h.Write([]byte{b}))
   100  }
   101  
   102  // Run encodes the rune r into writer w.
   103  func Rune(h hash.Hash, r rune) {
   104  	Int(h, int(r))
   105  }