Add initial version of Gzipping reader
parent
d2c5acc447
commit
55b3aaa805
@ -0,0 +1,58 @@
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package gzip
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import (
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"bytes"
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"compress/gzip"
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"io"
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)
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const DefaultBufferSize = 65536
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// Compressor is a wrapper around a gzip.Writer that reads from an io.Reader
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// and writes to an internal buffer. The internal buffer is used to store
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// compressed data until it is read by the caller.
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type Compressor struct {
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r io.Reader
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bufSz int
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buf *bytes.Buffer
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gzw *gzip.Writer
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}
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// NewCompressor returns an instantied Compressor that reads from r and
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// compresses the data using gzip.
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func NewCompressor(r io.Reader, bufSz int) *Compressor {
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buf := new(bytes.Buffer)
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return &Compressor{
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r: r,
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bufSz: bufSz,
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buf: buf,
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gzw: gzip.NewWriter(buf),
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}
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}
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// Read reads compressed data.
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func (c *Compressor) Read(p []byte) (int, error) {
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if c.buf.Len() == 0 {
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n, err := io.CopyN(c.gzw, c.r, int64(c.bufSz))
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if err != nil {
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c.gzw.Close() // Time to write the footer.
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if err != io.EOF {
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// Actual error, let caller handle
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return 0, err
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}
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} else if n > 0 {
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// We read some data, but didn't hit any error.
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// Just flush the data in the buffer, ready
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// to be read.
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if err := c.gzw.Flush(); err != nil {
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return 0, err
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}
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}
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}
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return c.buf.Read(p)
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}
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// Close closes the Compressor.
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func (c *Compressor) Close() error {
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return c.gzw.Close()
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}
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@ -0,0 +1,41 @@
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package gzip
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import (
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"bytes"
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"compress/gzip"
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"io"
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"testing"
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)
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func Test_Compressor_SingleRead(t *testing.T) {
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originalData := []byte("This is a test string, xxxxx -- xxxxxx -- test should compress")
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reader := bytes.NewReader(originalData)
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compressor := NewCompressor(reader, DefaultBufferSize)
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// Create a buffer to hold compressed data
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compressedBuffer := make([]byte, DefaultBufferSize)
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n, err := compressor.Read(compressedBuffer)
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if err != nil && err != io.EOF {
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t.Fatalf("Unexpected error while reading: %v", err)
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}
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// Decompress the compressed data
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r, err := gzip.NewReader(bytes.NewReader(compressedBuffer[:n]))
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if err != nil {
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t.Fatalf("Failed to create gzip reader: %v", err)
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}
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decompressedBuffer := new(bytes.Buffer)
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_, err = io.Copy(decompressedBuffer, r)
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if err != nil {
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t.Fatalf("Failed to decompress: %v", err)
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}
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// Verify the decompressed data matches original data
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if !bytes.Equal(decompressedBuffer.Bytes(), originalData) {
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t.Fatalf("Decompressed data does not match original. Got %v, expected %v", decompressedBuffer.Bytes(), originalData)
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}
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}
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func Test_Compressor_MultipleRead(t *testing.T) {
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}
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