snapshot of https://github.com/seaweedfs/seaweedfs.git (master, 2026-09-16; blobs > 131072B omitted)

weed/util/compression.go

@@ -0,0 +1,153 @@
+package util
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+
+	"github.com/seaweedfs/seaweedfs/weed/glog"
+	// "github.com/klauspost/compress/zstd"
+)
+
+var (
+	UnsupportedCompression = fmt.Errorf("unsupported compression")
+)
+
+func MaybeGzipData(input []byte) []byte {
+	if IsGzippedContent(input) {
+		return input
+	}
+	gzipped, err := GzipData(input)
+	if err != nil {
+		return input
+	}
+	if len(gzipped)*10 > len(input)*9 {
+		return input
+	}
+	return gzipped
+}
+
+func MaybeDecompressData(input []byte) []byte {
+	uncompressed, err := DecompressData(input)
+	if err != nil {
+		if err != UnsupportedCompression {
+			glog.Errorf("decompressed data: %v", err)
+		}
+		return input
+	}
+	return uncompressed
+}
+
+func GzipData(input []byte) ([]byte, error) {
+	w := new(bytes.Buffer)
+	_, err := GzipStream(w, bytes.NewReader(input))
+	if err != nil {
+		return nil, err
+	}
+	return w.Bytes(), nil
+}
+
+func ungzipData(input []byte) ([]byte, error) {
+	w := new(bytes.Buffer)
+	_, err := GunzipStream(w, bytes.NewReader(input))
+	if err != nil {
+		return nil, err
+	}
+	return w.Bytes(), nil
+}
+
+func DecompressData(input []byte) ([]byte, error) {
+	if IsGzippedContent(input) {
+		return ungzipData(input)
+	}
+	/*
+		if IsZstdContent(input) {
+			return unzstdData(input)
+		}
+	*/
+	return input, UnsupportedCompression
+}
+
+func IsGzippedContent(data []byte) bool {
+	if len(data) < 2 {
+		return false
+	}
+	return data[0] == 31 && data[1] == 139
+}
+
+/*
+var zstdEncoder, _ = zstd.NewWriter(nil)
+
+func ZstdData(input []byte) ([]byte, error) {
+	return zstdEncoder.EncodeAll(input, nil), nil
+}
+
+var decoder, _ = zstd.NewReader(nil)
+
+func unzstdData(input []byte) ([]byte, error) {
+	return decoder.DecodeAll(input, nil)
+}
+
+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", ".br":
+		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.HasSuffix(mtype, "vnd.rar") {
+			return false, 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
+}