从阅读器读取直到到达字符串

Question

I am trying to write a function to keep reading from a buffered reader until I hit a certain string, then to stop reading and return everything read prior to that string.

In other words, I want to do the same thing as reader.ReadString() does, except taking a string instead of a single byte.

For instance:

mydata, err := reader.ReadString("
.
") //obviously will not compile

How can I do this?

Thanks in advance,

Twichy

Amendment 1: Previous attempt

Here is my previous attempt; its badly written and doesnt work but hopefully it demonstrates what I am trying to do.

func readDotData(reader *bufio.Reader)(string, error){
delims := []byte{ '', '
', '.', '', '
'}
curpos := 0
var buffer []byte
for {
    curpos = 0
    data, err := reader.ReadSlice(delims[0])
    if err!=nil{ return "", err }
    buffer = append(buffer, data...)
    for {
        curpos++
        b, err := reader.ReadByte()
        if err!=nil{ return "", err }
        if b!=delims[curpos]{
            for curpos >= 0{
                buffer = append(buffer, delims[curpos])
                curpos--
            }
            break
        }
        if curpos == len(delims){
            return string(buffer[len(buffer)-1:]), nil
        }
    }
}
panic("unreachable")
}

Answer 1

http://play.golang.org/p/BpA5pOc-Rn

package main

import (
    "bytes"
    "fmt"
)

func main() {
    b := bytes.NewBuffer([]byte("Hello, playground!
.
Irrelevant trailer."))
    c := make([]byte, 0, b.Len())
    for {
        p := b.Bytes()
        if bytes.Equal(p[:5], []byte("
.
")) {
            fmt.Println(string(c))
            return
        }
        c = append(c, b.Next(1)...)

    }
}