util

Documentation

Overview

Package util is a very generic package that is used to contain simple functions that may be used in multiple packages, such as the simple random number generator.

Generic re-implementations of built-in Golang structs or functions also sometimes land in here.

This package is affected by the "stdrand" build tag, which will replace the "fastrand" implementation with the "math/rand" random struct.

Index

• Variables
• func FastRand() uint32
• func FastRandN(n int) uint32
• type Builder
  • func (b *Builder) Cap() int
  • func (b *Builder) Grow(n int)
  • func (b *Builder) InsertByte(c byte) error
  • func (b *Builder) Len() int
  • func (b *Builder) Output() string
  • func (b *Builder) Reset()
  • func (b *Builder) String() string
  • func (b *Builder) Write(p []byte) (int, error)
  • func (b *Builder) WriteByte(c byte) error
  • func (b *Builder) WriteString(s string) (int, error)

Variables

var Rand = getRandom()

Rand is the custom Random number generator, based on the current time as a seed.

This struct is overridden by the tag "stdrand". By default, it will use the "unsafe" fastrand() implentation which is faster, but contains less entropy than the built-in, 'rand.Rand', which requires more memory and binary storage space.

Functions

func FastRand

func FastRand() uint32

FastRand is a fast thread local random function. This should be used in place instead of 'Rand.Uint32()'.

Taken from https://github.com/dgraph-io/ristretto/blob/master/z/rtutil.go Thanks!

func FastRandN

func FastRandN(n int) uint32

FastRandN is a fast thread local random function. This should be used in place instead of 'Rand.Uint32n()'.

This function will take a max value to specify.

Types

type Builder

type Builder struct {
	// contains filtered or unexported fields
}

A Builder is used to efficiently build a string using Write methods. It minimizes memory copying. The zero value is ready to use. Do not copy a non-zero Builder.

Re-implemented to remove UTF8 dependency and added some useful functions. Copy-check was also removed.

func (*Builder) Cap

func (b *Builder) Cap() int

Cap returns the capacity of the builder's underlying byte slice. It is the total space allocated for the string being built and includes any bytes already written.

func (*Builder) Grow

func (b *Builder) Grow(n int)

Grow grows b's capacity, if necessary, to guarantee space for another n bytes.

After Grow(n), at least n bytes can be written to b without another allocation. If n is negative, Grow is a NOP.

func (*Builder) InsertByte

func (b *Builder) InsertByte(c byte) error

InsertByte appends the byte c to b's buffer at the zero position.

The returned error is always nil.

func (*Builder) Len

func (b *Builder) Len() int

Len returns the number of accumulated bytes; b.Len() == len(b.String()).

func (*Builder) Output

func (b *Builder) Output() string

Output returns the accumulated string, then resets the value of this Builder.

func (*Builder) Reset

func (b *Builder) Reset()

Reset resets the Builder to be empty.

func (*Builder) String

func (b *Builder) String() string

String returns the accumulated string.

func (*Builder) Write

func (b *Builder) Write(p []byte) (int, error)

Write appends the contents of p to b's buffer.

Write always returns len(p), nil.

func (*Builder) WriteByte

func (b *Builder) WriteByte(c byte) error

WriteByte appends the byte c to b's buffer.

The returned error is always nil.

func (*Builder) WriteString

func (b *Builder) WriteString(s string) (int, error)

WriteString appends the contents of s to b's buffer.

It returns the length of s and a nil error.