Struct: aws.WriteAtBuffer

import "../ibm-cos-sdk-go/aws"

Overview

A WriteAtBuffer provides a in memory buffer supporting the io.WriterAt interface Can be used with the s3manager.Downloader to download content to a buffer in memory. Safe to use concurrently.

Implemented Interfaces

s3crypto.Cipher, s3manager.ReadSeekerWriteTo, awserr.UnmarshalError, s3manager.WriterReadFrom

Structure Field Summary

• GrowthCoeff float64

  GrowthCoeff defines the growth rate of the internal buffer.

Constructor Functions

• func NewWriteAtBuffer(buf []byte) *WriteAtBuffer

  NewWriteAtBuffer creates a WriteAtBuffer with an internal buffer provided by buf.

Method Summary

• func (b *WriteAtBuffer) Bytes() []byte

  Bytes returns a slice of bytes written to the buffer.

• func (b *WriteAtBuffer) WriteAt(p []byte, pos int64) (n int, err error)

  WriteAt writes a slice of bytes to a buffer starting at the position provided The number of bytes written will be returned, or error.

Structure Field Details

GrowthCoeff float64

GrowthCoeff defines the growth rate of the internal buffer. By default, the growth rate is 1, where expanding the internal buffer will allocate only enough capacity to fit the new expected length.

Function Details

func NewWriteAtBuffer(buf []byte) *WriteAtBuffer

NewWriteAtBuffer creates a WriteAtBuffer with an internal buffer provided by buf.

// File 'aws/types.go', line 175

func NewWriteAtBuffer(buf []byte) *WriteAtBuffer {
	return &WriteAtBuffer{buf: buf}
}

Method Details

func (b *WriteAtBuffer) Bytes() []byte

Bytes returns a slice of bytes written to the buffer.

// File 'aws/types.go', line 203

func (b *WriteAtBuffer) Bytes() []byte {
	b.m.Lock()
	defer b.m.Unlock()
	return b.buf
}

func (b *WriteAtBuffer) WriteAt(p []byte, pos int64) (n int, err error)

WriteAt writes a slice of bytes to a buffer starting at the position provided The number of bytes written will be returned, or error. Can overwrite previous written slices if the write ats overlap.

// File 'aws/types.go', line 182

func (b *WriteAtBuffer) WriteAt(p []byte, pos int64) (n int, err error) {
	pLen := len(p)
	expLen := pos + int64(pLen)
	b.m.Lock()
	defer b.m.Unlock()
	if int64(len(b.buf)) < expLen {
		if int64(cap(b.buf)) < expLen {
			if b.GrowthCoeff < 1 {
				b.GrowthCoeff = 1
			}
			newBuf := make([]byte, expLen, int64(b.GrowthCoeff*float64(expLen)))
			copy(newBuf, b.buf)
			b.buf = newBuf
		}
		b.buf = b.buf[:expLen]
	}
	copy(b.buf[pos:], p)
	return pLen, nil
}