func newGzip(b *siegreader.Buffer, path string) (decompressor, error) {
b.Quit = make(chan struct{}) // in case a stream with a closed quit channel, make a new one
_ = b.SizeNow() // in case a stream, force full read
buf, err := b.EofSlice(0, 4) // gzip stores uncompressed size in last 4 bytes of the stream
if err != nil {
return nil, err
}
sz := int64(uint32(buf[0]) | uint32(buf[1])<<8 | uint32(buf[2])<<16 | uint32(buf[3])<<24)
g, err := gzip.NewReader(siegreader.ReaderFrom(b))
return &gzipD{sz: sz, p: path, rdr: g}, err
}
// identify function - brings a new matcher into existence
func (b *Matcher) identify(buf *siegreader.Buffer, quit chan struct{}, r chan core.Result, exclude ...int) {
buf.Quit = quit
waitSet := b.priorities.WaitSet(exclude...)
var maxBOF, maxEOF int
if len(exclude) > 0 {
maxBOF, maxEOF = waitSet.MaxOffsets()
} else {
maxBOF, maxEOF = b.maxBOF, b.maxEOF
}
incoming := b.scorer(buf, waitSet, quit, r)
rdr := siegreader.LimitReaderFrom(buf, maxBOF)
// First test BOF frameset
bfchan := b.bofFrames.index(buf, false, quit)
for bf := range bfchan {
if config.Debug() {
fmt.Fprintln(config.Out(), strike{b.bofFrames.testTreeIndex[bf.idx], 0, bf.off, bf.length, false, true})
}
incoming <- strike{b.bofFrames.testTreeIndex[bf.idx], 0, bf.off, bf.length, false, true}
}
select {
case <-quit: // the matcher has called quit
for range bfchan {
} // drain first
close(incoming)
return
default:
}
// Do an initial check of BOF sequences
b.start(true) // start bof matcher if not yet started
var bchan chan wac.Result
bchan = b.bAho.Index(rdr)
for br := range bchan {
if br.Index[0] == -1 {
incoming <- progressStrike(br.Offset, false)
if br.Offset > 131072 && (maxBOF < 0 || maxBOF > maxEOF*5) { // del buf.Stream 2^16 65536 2^17 131072
break
}
} else {
if config.Debug() {
fmt.Fprintln(config.Out(), strike{b.bofSeq.testTreeIndex[br.Index[0]], br.Index[1], br.Offset, br.Length, false, false})
}
incoming <- strike{b.bofSeq.testTreeIndex[br.Index[0]], br.Index[1], br.Offset, br.Length, false, false}
}
}
select {
case <-quit: // the matcher has called quit
for range bchan {
} // drain first
close(incoming)
return
default:
}
// Setup EOF tests
efchan := b.eofFrames.index(buf, true, quit)
b.start(false)
rrdr := siegreader.LimitReverseReaderFrom(buf, maxEOF)
echan := b.eAho.Index(rrdr)
// if we have a maximum value on EOF do a sequential search
if maxEOF >= 0 {
if maxEOF != 0 {
_, _ = buf.CanSeek(0, true) // force a full read to enable EOF scan to proceed for streams
}
for ef := range efchan {
if config.Debug() {
fmt.Fprintln(config.Out(), strike{b.eofFrames.testTreeIndex[ef.idx], 0, ef.off, ef.length, true, true})
}
incoming <- strike{b.eofFrames.testTreeIndex[ef.idx], 0, ef.off, ef.length, true, true}
}
// Scan complete EOF
for er := range echan {
if er.Index[0] == -1 {
incoming <- progressStrike(er.Offset, true)
} else {
if config.Debug() {
fmt.Fprintln(config.Out(), strike{b.eofSeq.testTreeIndex[er.Index[0]], er.Index[1], er.Offset, er.Length, true, false})
}
incoming <- strike{b.eofSeq.testTreeIndex[er.Index[0]], er.Index[1], er.Offset, er.Length, true, false}
}
}
// send a final progress strike with the maximum EOF
incoming <- progressStrike(int64(maxEOF), true)
// Finally, finish BOF scan
for br := range bchan {
if br.Index[0] == -1 {
incoming <- progressStrike(br.Offset, false)
} else {
if config.Debug() {
fmt.Fprintln(config.Out(), strike{b.bofSeq.testTreeIndex[br.Index[0]], br.Index[1], br.Offset, br.Length, false, false})
}
incoming <- strike{b.bofSeq.testTreeIndex[br.Index[0]], br.Index[1], br.Offset, br.Length, false, false}
}
}
close(incoming)
return
}
// If no maximum on EOF do a parallel search
for {
select {
case br, ok := <-bchan:
if !ok {
if maxBOF < 0 && maxEOF != 0 {
_, _ = buf.CanSeek(0, true) // if we've a limit BOF reader, force a full read to enable EOF scan to proceed for streams
}
bchan = nil
} else {
if br.Index[0] == -1 {
incoming <- progressStrike(br.Offset, false)
} else {
if config.Debug() {
fmt.Fprintln(config.Out(), strike{b.bofSeq.testTreeIndex[br.Index[0]], br.Index[1], br.Offset, br.Length, false, false})
}
incoming <- strike{b.bofSeq.testTreeIndex[br.Index[0]], br.Index[1], br.Offset, br.Length, false, false}
}
}
case ef, ok := <-efchan:
if !ok {
efchan = nil
} else {
if config.Debug() {
fmt.Fprintln(config.Out(), strike{b.eofFrames.testTreeIndex[ef.idx], 0, ef.off, ef.length, true, true})
}
incoming <- strike{b.eofFrames.testTreeIndex[ef.idx], 0, ef.off, ef.length, true, true}
}
case er, ok := <-echan:
if !ok {
echan = nil
} else {
if er.Index[0] == -1 {
incoming <- progressStrike(er.Offset, true)
} else {
if config.Debug() {
fmt.Fprintln(config.Out(), strike{b.eofSeq.testTreeIndex[er.Index[0]], er.Index[1], er.Offset, er.Length, true, false})
}
incoming <- strike{b.eofSeq.testTreeIndex[er.Index[0]], er.Index[1], er.Offset, er.Length, true, false}
}
}
}
if bchan == nil && efchan == nil && echan == nil {
close(incoming)
return
}
}
}