Add initial version of Gzipping reader

store/gzip/compressor.go

@@ -0,0 +1,58 @@
+package gzip
+
+import (
+	"bytes"
+	"compress/gzip"
+	"io"
+)
+
+const DefaultBufferSize = 65536
+
+// Compressor is a wrapper around a gzip.Writer that reads from an io.Reader
+// and writes to an internal buffer.  The internal buffer is used to store
+// compressed data until it is read by the caller.
+type Compressor struct {
+	r     io.Reader
+	bufSz int
+	buf   *bytes.Buffer
+	gzw   *gzip.Writer
+}
+
+// NewCompressor returns an instantied Compressor that reads from r and
+// compresses the data using gzip.
+func NewCompressor(r io.Reader, bufSz int) *Compressor {
+	buf := new(bytes.Buffer)
+	return &Compressor{
+		r:     r,
+		bufSz: bufSz,
+		buf:   buf,
+		gzw:   gzip.NewWriter(buf),
+	}
+}
+
+// Read reads compressed data.
+func (c *Compressor) Read(p []byte) (int, error) {
+	if c.buf.Len() == 0 {
+		n, err := io.CopyN(c.gzw, c.r, int64(c.bufSz))
+		if err != nil {
+			c.gzw.Close() // Time to write the footer.
+			if err != io.EOF {
+				// Actual error, let caller handle
+				return 0, err
+			}
+		} else if n > 0 {
+			// We read some data, but didn't hit any error.
+			// Just flush the data in the buffer, ready
+			// to be read.
+			if err := c.gzw.Flush(); err != nil {
+				return 0, err
+			}
+		}
+	}
+	return c.buf.Read(p)
+}
+
+// Close closes the Compressor.
+func (c *Compressor) Close() error {
+	return c.gzw.Close()
+}

store/gzip/compressor_test.go

@@ -0,0 +1,41 @@
+package gzip
+
+import (
+	"bytes"
+	"compress/gzip"
+	"io"
+	"testing"
+)
+
+func Test_Compressor_SingleRead(t *testing.T) {
+	originalData := []byte("This is a test string, xxxxx -- xxxxxx -- test should compress")
+	reader := bytes.NewReader(originalData)
+	compressor := NewCompressor(reader, DefaultBufferSize)
+
+	// Create a buffer to hold compressed data
+	compressedBuffer := make([]byte, DefaultBufferSize)
+
+	n, err := compressor.Read(compressedBuffer)
+	if err != nil && err != io.EOF {
+		t.Fatalf("Unexpected error while reading: %v", err)
+	}
+
+	// Decompress the compressed data
+	r, err := gzip.NewReader(bytes.NewReader(compressedBuffer[:n]))
+	if err != nil {
+		t.Fatalf("Failed to create gzip reader: %v", err)
+	}
+	decompressedBuffer := new(bytes.Buffer)
+	_, err = io.Copy(decompressedBuffer, r)
+	if err != nil {
+		t.Fatalf("Failed to decompress: %v", err)
+	}
+
+	// Verify the decompressed data matches original data
+	if !bytes.Equal(decompressedBuffer.Bytes(), originalData) {
+		t.Fatalf("Decompressed data does not match original. Got %v, expected %v", decompressedBuffer.Bytes(), originalData)
+	}
+}
+
+func Test_Compressor_MultipleRead(t *testing.T) {
+}