1 files changed, 126 insertions, 0 deletions
diff --git a/weed/util/compression.go b/weed/util/compression.go
new file mode 100644
index 000000000..b526f47c9
--- /dev/null
+++ b/weed/util/compression.go
@@ -0,0 +1,126 @@
+package util
+
+import (
+	"bytes"
+	"compress/flate"
+	"compress/gzip"
+	"fmt"
+	"io/ioutil"
+	"strings"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/klauspost/compress/zstd"
+)
+
+func GzipData(input []byte) ([]byte, error) {
+	buf := new(bytes.Buffer)
+	w, _ := gzip.NewWriterLevel(buf, flate.BestSpeed)
+	if _, err := w.Write(input); err != nil {
+		glog.V(2).Infoln("error compressing data:", err)
+		return nil, err
+	}
+	if err := w.Close(); err != nil {
+		glog.V(2).Infoln("error closing compressed data:", err)
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+var zstdEncoder, _ = zstd.NewWriter(nil)
+
+func ZstdData(input []byte) ([]byte, error) {
+	return zstdEncoder.EncodeAll(input, nil), nil
+}
+
+func DecompressData(input []byte) ([]byte, error) {
+	if IsGzippedContent(input) {
+		return ungzipData(input)
+	}
+	if IsZstdContent(input) {
+		return unzstdData(input)
+	}
+	return nil, fmt.Errorf("unsupported compression")
+}
+
+func ungzipData(input []byte) ([]byte, error) {
+	buf := bytes.NewBuffer(input)
+	r, _ := gzip.NewReader(buf)
+	defer r.Close()
+	output, err := ioutil.ReadAll(r)
+	if err != nil {
+		glog.V(2).Infoln("error uncompressing data:", err)
+	}
+	return output, err
+}
+
+var decoder, _ = zstd.NewReader(nil)
+func unzstdData(input []byte) ([]byte, error) {
+	return decoder.DecodeAll(input, nil)
+}
+
+func IsGzippedContent(data []byte) bool {
+	if len(data) < 2 {
+		return false
+	}
+	return data[0] == 31 && data[1] == 139
+}
+
+func IsZstdContent(data []byte) bool {
+	if len(data) < 4 {
+		return false
+	}
+	return data[3] == 0xFD && data[2] == 0x2F && data[1] == 0xB5 && data[0] == 0x28
+}
+
+/*
+* Default not to compressed since compression can be done on client side.
+ */func IsCompressableFileType(ext, mtype string) (shouldBeCompressed, iAmSure bool) {
+
+	// text
+	if strings.HasPrefix(mtype, "text/") {
+		return true, true
+	}
+
+	// images
+	switch ext {
+	case ".svg", ".bmp", ".wav":
+		return true, true
+	}
+	if strings.HasPrefix(mtype, "image/") {
+		return false, true
+	}
+
+	// by file name extension
+	switch ext {
+	case ".zip", ".rar", ".gz", ".bz2", ".xz", ".zst":
+		return false, true
+	case ".pdf", ".txt", ".html", ".htm", ".css", ".js", ".json":
+		return true, true
+	case ".php", ".java", ".go", ".rb", ".c", ".cpp", ".h", ".hpp":
+		return true, true
+	case ".png", ".jpg", ".jpeg":
+		return false, true
+	}
+
+	// by mime type
+	if strings.HasPrefix(mtype, "application/") {
+		if strings.HasSuffix(mtype, "zstd") {
+			return false, true
+		}
+		if strings.HasSuffix(mtype, "xml") {
+			return true, true
+		}
+		if strings.HasSuffix(mtype, "script") {
+			return true, true
+		}
+	}
+
+	if strings.HasPrefix(mtype, "audio/") {
+		switch strings.TrimPrefix(mtype, "audio/") {
+		case "wave", "wav", "x-wav", "x-pn-wav":
+			return true, true
+		}
+	}
+
+	return false, false
+}