func RecompressGZip(path string, fo os.FileInfo) error {
file, err := os.Open(path)
if err != nil {
return err
}
defer file.Close()
gzipReader, err := gzip.NewReader(file)
if err != nil {
return err
}
defer gzipReader.Close()
data, err := ioutil.ReadAll(gzipReader)
if err != nil {
return err
}
output, err := os.OpenFile(path+".tmp", os.O_CREATE|os.O_WRONLY, fo.Mode())
if err != nil {
return nil
}
options := zopfli.DefaultOptions()
err = zopfli.GzipCompress(&options, data, output)
if err != nil {
output.Close()
os.Remove(path + ".tmp")
return err
}
output.Close()
err = os.Rename(path+".tmp", path)
return err
}
func main() {
options := zopfli.DefaultOptions()
flag.BoolVar(&options.Verbose, "v", options.Verbose, "verbose mode")
flag.BoolVar(&options.VerboseMore, "vv", options.VerboseMore, "more verbose mode")
outputToStdout := flag.Bool("c", false, "write the result on standard output, instead of disk")
deflate := flag.Bool("deflate", false, "output to deflate format instead of gzip")
zlib := flag.Bool("zlib", false, "output to zlib format instead of gzip")
gzip := flag.Bool("gzip", true, "output to gzip format")
flag.BoolVar(&options.BlockSplittingLast, "splitlast", options.BlockSplittingLast, "do block splitting last instead of first")
flag.IntVar(&options.NumIterations, "i", options.NumIterations, "perform # iterations (default 15). More gives more compression but is slower. Examples: -i=10, -i=50, -i=1000")
var cpuProfile string
flag.StringVar(&cpuProfile, "cpuprofile", "", "write cpu profile to file")
flag.BoolVar(¶llel, "parallel", false, "compress in parallel (gzip only); use GOMAXPROCS to set the amount of parallelism. More parallelism = smaller independent chunks, thus worse compression ratio.")
flag.Parse()
if parallel && !*gzip {
fmt.Fprintf(os.Stderr, "Error: parallel is only supported with gzip containers.")
return
}
if options.VerboseMore {
options.Verbose = true
}
var outputType int
if *deflate && !*zlib && !*gzip {
outputType = zopfli.FORMAT_DEFLATE
} else if *zlib && !*deflate && !*gzip {
outputType = zopfli.FORMAT_ZLIB
} else {
outputType = zopfli.FORMAT_GZIP
}
if options.NumIterations < 1 {
fmt.Fprintf(os.Stderr, "Error: must have 1 or more iterations")
return
}
var allFileNames []string
if *outputToStdout {
allFileNames = append(allFileNames, "")
} else {
allFileNames = flag.Args()
}
if len(allFileNames) <= 0 {
fmt.Fprintf(os.Stderr, "Please provide filename\n")
}
if cpuProfile != "" {
f, err := os.Create(cpuProfile)
if err == nil {
pprof.StartCPUProfile(f)
defer f.Close()
defer pprof.StopCPUProfile()
}
}
for _, fileName := range allFileNames {
var outFileName string
if *outputToStdout {
outFileName = ""
} else {
switch outputType {
case zopfli.FORMAT_GZIP:
outFileName = fileName + ".gz"
case zopfli.FORMAT_ZLIB:
outFileName = fileName + ".zlib"
case zopfli.FORMAT_DEFLATE:
outFileName = fileName + ".deflate"
default:
panic("Unknown output type")
}
if options.Verbose {
fmt.Fprintf(os.Stderr, "Saving to: %s\n", outFileName)
}
}
compressErr := compressFile(&options, outputType, fileName, outFileName)
if compressErr != nil {
fmt.Fprintf(os.Stderr, "could not compress %s: %v\n", fileName, compressErr)
}
}
}