github.com/grailbio/base@v0.0.11/recordio/example_basic_test.go (about)

     1  package recordio_test
     2  
     3  import (
     4  	"bytes"
     5  	"fmt"
     6  	"io"
     7  
     8  	"github.com/grailbio/base/recordio"
     9  	"github.com/grailbio/base/recordio/recordioflate"
    10  )
    11  
    12  func init() {
    13  	recordioflate.Init()
    14  }
    15  
    16  func doWrite(out io.Writer) {
    17  	wr := recordio.NewWriter(out, recordio.WriterOpts{
    18  		Transformers: []string{"flate"},
    19  		Marshal:      func(scratch []byte, v interface{}) ([]byte, error) { return []byte(v.(string)), nil },
    20  	})
    21  	wr.Append("Item0")
    22  	wr.Append("Item1")
    23  	if err := wr.Finish(); err != nil {
    24  		panic(err)
    25  	}
    26  }
    27  
    28  func doRead(in io.ReadSeeker) {
    29  	r := recordio.NewScanner(in, recordio.ScannerOpts{
    30  		Unmarshal: func(data []byte) (interface{}, error) { return string(data), nil },
    31  	})
    32  	for r.Scan() {
    33  		fmt.Printf("Item: %s\n", r.Get().(string))
    34  	}
    35  	if err := r.Err(); err != nil {
    36  		panic(err)
    37  	}
    38  }
    39  
    40  // Example_basic demonstrates basic reads, writes, and flate complession.
    41  func Example_basic() {
    42  	buf := &bytes.Buffer{}
    43  	doWrite(buf)
    44  	doRead(bytes.NewReader(buf.Bytes()))
    45  	// Output:
    46  	// Item: Item0
    47  	// Item: Item1
    48  }