50 lines
1.2 KiB
Go
50 lines
1.2 KiB
Go
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package press
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// This file implements the gzip algorithm.
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import (
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"bufio"
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"compress/gzip"
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"io"
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)
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// GzipHeader - Header we add to a gzip file. We're contatenating GZIP files here, so we don't need this.
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var GzipHeader = []byte{}
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// Function that compresses a block using gzip
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func (c *Compression) compressBlockGz(in []byte, out io.Writer, compressionLevel int) (compressedSize uint32, uncompressedSize int64, err error) {
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// Initialize buffer
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bufw := bufio.NewWriterSize(out, int(c.maxCompressedBlockSize()))
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// Initialize block writer
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outw, err := gzip.NewWriterLevel(bufw, compressionLevel)
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if err != nil {
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return 0, 0, err
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}
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// Compress block
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_, err = outw.Write(in)
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if err != nil {
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return 0, 0, err
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}
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// Finalize gzip file, flush buffer and return
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err = outw.Close()
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if err != nil {
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return 0, 0, err
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}
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blockSize := uint32(bufw.Buffered())
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err = bufw.Flush()
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return blockSize, int64(len(in)), err
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}
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// Utility function to decompress a block range using gzip
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func decompressBlockRangeGz(in io.Reader, out io.Writer) (n int, err error) {
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gzipReader, err := gzip.NewReader(in)
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if err != nil {
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return 0, err
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}
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written, err := io.Copy(out, gzipReader)
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return int(written), err
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}
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