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Example: How to use ReadAtLeast from IO Package in Golang?

ReadAtLeast reads from r into buf until it has read at least min bytes. It returns specific errors to signal specific cases when the minimum couldn’t be read due to EOF.

Example

package main

import (
	"io"
	"fmt"
	"strings"
)

type Example struct {
	ReaderLength int
	Minimum  int
	TextStr  string
}

func main() {
	examples := []Example{
		{10, 5, "Go is a programming language created at Google in 2007."},
		{10, 10, "Golang"},
		{10, 00, "Robert Griesemer"},
		{10, 15, "Jobs, Code, Videos and News for Go hackers."},
	}
	for _, ex := range examples {
		rd := strings.NewReader(ex.TextStr)
		buffer := make([]byte, ex.ReaderLength)
		bytesRead, err := io.ReadAtLeast(rd, buffer, ex.Minimum)
		fmt.Printf("\nLen(buffer)=%d, Min=%d, BytesRead=%d, Error=%v, (%s)\n",ex.ReaderLength, ex.Minimum, bytesRead, err, ex.TextStr)
	}
}

Output

Len(buffer)=10, Min=5, BytesRead=10, Error=, (Go is a programming language created at Google in 2007.)

Len(buffer)=10, Min=10, BytesRead=6, Error=unexpected EOF, (Golang)

Len(buffer)=10, Min=0, BytesRead=0, Error=, (Robert Griesemer)

Len(buffer)=10, Min=15, BytesRead=0, Error=short buffer, (Jobs, Code, Videos and News for Go hackers.)
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