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package flatex
import (
"io"
"sync"
"git.sr.ht/~runxiyu/furgit/internal/bufpool"
)
// bufferDecompressor wraps the custom slice inflater so byte-slice
// decompressions avoid repeated allocations.
type bufferDecompressor struct {
inflater sliceInflater
}
var bufferDecompressorPool = sync.Pool{
New: func() any {
fixedHuffmanDecoderInit()
d := &bufferDecompressor{}
d.inflater.bits = new([maxNumLit + maxNumDist]int)
d.inflater.codebits = new([numCodes]int)
return d
},
}
// Decompress inflates the provided DEFLATE stream and returns the full output
// in a pooled bufpool.Buffer along with the number of consumed bytes from src.
func Decompress(src []byte) (bufpool.Buffer, int, error) {
return DecompressDict(src, nil)
}
// DecompressDict inflates the provided DEFLATE stream using dict as the preset
// dictionary and returns the full output in a pooled bufpool.Buffer. The second
// returned value reports how many bytes of src were consumed.
func DecompressDict(src []byte, dict []byte) (bufpool.Buffer, int, error) {
d := bufferDecompressorPool.Get().(*bufferDecompressor)
defer bufferDecompressorPool.Put(d)
if err := d.inflater.reset(src, dict); err != nil {
return bufpool.Buffer{}, 0, err
}
out := bufpool.Borrow(bufpool.DefaultBufferCap)
out.Resize(0)
for {
if len(d.inflater.toRead) > 0 {
out.Append(d.inflater.toRead)
d.inflater.toRead = nil
continue
}
if d.inflater.err != nil {
if d.inflater.err == io.EOF {
return out, d.inflater.pos, nil
}
out.Release()
return bufpool.Buffer{}, 0, d.inflater.err
}
d.inflater.step(&d.inflater)
if d.inflater.err != nil && len(d.inflater.toRead) == 0 {
d.inflater.toRead = d.inflater.dict.readFlush()
}
}
}
|
