doutan5844
2018-09-06 13:45
浏览 62
已采纳

GoLang链接io.Reader

I'm trying to implement a proxy pattern to chain transformations on io.Reader, in order to handle chunk of bytes efficiently.

  1. We cannot use pointers on receivers, so my solution seem not very efficient

  2. The code below say "process take too long"

Complete example at: https://play.golang.org/p/KhM0VXLq4CO

b := bytes.NewBufferString(text)
t := transformReaderHandler(*b)
readByChunk(t)

type transformReaderHandler bytes.Buffer

func (t transformReaderHandler) Read(p []byte) (n int, err error) {
    n, err = (*bytes.Buffer)(&t).Read(p)
    //if n > 0 {
    //  Do Something on the chunk
    //}
    return
}

Do you have any more efficient (memory efficient, computationally efficient) solution ?

Why do this code is not working ?

EDIT: The implementation of @svsd solution : https://play.golang.org/p/VUpJcyKLB6D

package main

import (
    "io"
    "fmt"
    "bytes"
)

const text = "Reaaaaally long and complex text to read in chunk"

func main() {
    b := bytes.NewBufferString(text)

    t := (*transformReaderHandler)(b)

    readByChunk(t)
}

type transformReaderHandler bytes.Buffer

func (t *transformReaderHandler) Read(p []byte) (n int, err error) {
    n, err = (*bytes.Buffer)(t).Read(p)
    if n > 0 {
        p[0] = 'X'
    }
    return
}

func readByChunk(r io.Reader) {
    var p = make([]byte, 4)

    for {
        n, err := r.Read(p)
        if err == io.EOF {
            break
        }
        fmt.Println(string(p[:n]))
    }
}
  • 写回答
  • 好问题 提建议
  • 追加酬金
  • 关注问题
  • 邀请回答

2条回答 默认 最新

相关推荐 更多相似问题