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
}
func (fs *frameSet) index(buf *siegreader.Buffer, rev bool, quit chan struct{}) chan fsmatch {
ret := make(chan fsmatch)
go func() {
for i, f := range fs.set {
select {
case <-quit:
close(ret)
return
default:
}
var match bool
var matches []int
if rev {
slc, err := buf.EofSlice(0, frames.TotalLength(f))
if err != nil {
close(ret)
return
}
match, matches = f.MatchR(slc)
} else {
slc, err := buf.Slice(0, frames.TotalLength(f))
if err != nil {
close(ret)
return
}
match, matches = f.Match(slc)
}
if match {
var min int
if !rev {
min, _ = f.Length()
}
for _, off := range matches {
ret <- fsmatch{i, int64(off - min), min}
}
}
}
close(ret)
}()
return ret
}
func (b *Matcher) scorer(buf *siegreader.Buffer, waitSet *priority.WaitSet, q chan struct{}, r chan<- core.Result) chan<- strike {
incoming := make(chan strike)
hits := make(map[int]*hitItem)
strikes := make(map[int]*strikeItem)
var bof int64
var eof int64
var quitting bool
quit := func() {
close(q)
quitting = true
}
newHit := func(i int) *hitItem {
l := len(b.keyFrames[i])
hit := &hitItem{
potentialIdxs: make([]int, l),
partials: make([][][2]int64, l),
}
hits[i] = hit
return hit
}
// given the current bof and eof, is there anything worth waiting for?
continueWaiting := func(w []int) bool {
var keepScanning bool
// now for each of the possible signatures we are either waiting on or have partial/potential matches for, check whether there are live contenders
for _, v := range w {
kf := b.keyFrames[v]
for i, f := range kf {
off := bof
if f.typ > frames.PREV {
off = eof
}
var waitfor, excludable bool
if f.key.pMax == -1 || f.key.pMax+int64(f.key.lMax) > off {
waitfor = true
} else if hit, ok := hits[v]; ok {
if hit.partials[i] != nil {
waitfor = true
} else if hit.potentialIdxs[i] > 0 && strikes[hit.potentialIdxs[i]-1].hasPotential() {
waitfor, excludable = true, true
}
}
// if we've got to the end of the signature, and have determined this is a live one - return immediately & continue scan
if waitfor {
if i == len(kf)-1 {
if !config.Slow() || !config.Checkpoint(bof) {
return true
}
keepScanning = true
fmt.Fprintf(config.Out(), "waiting on: %d, potentially excludable: %t\n", v, excludable)
}
continue
}
break
}
}
return keepScanning
}
testStrike := func(st strike) []kfHit {
// the offsets we *record* are always BOF offsets - these can be interpreted as EOF offsets when necessary
off := st.offset
if st.reverse {
off = buf.Size() - st.offset - int64(st.length)
}
// grab the relevant testTree
t := b.tests[st.idxa+st.idxb]
res := make([]kfHit, 0, 10)
// immediately apply key frames for the completes
for _, kf := range t.complete {
if b.keyFrames[kf[0]][kf[1]].check(st.offset) && waitSet.Check(kf[0]) {
res = append(res, kfHit{kf, off, st.length})
}
}
// if there are no incompletes, we are done
if len(t.incomplete) < 1 {
return res
}
// see what incompletes are worth pursuing
var checkl, checkr bool
for _, v := range t.incomplete {
if checkl && checkr {
break
}
if b.keyFrames[v.kf[0]][v.kf[1]].check(st.offset) && waitSet.Check(v.kf[0]) {
if v.l {
checkl = true
}
if v.r {
checkr = true
}
}
}
if !checkl && !checkr {
return res
}
// calculate the offset and lengths for the left and right test slices
var lslc, rslc []byte
var lpos, rpos int64
var llen, rlen int
if st.reverse {
lpos, llen = st.offset+int64(st.length), t.maxLeftDistance
rpos, rlen = st.offset-int64(t.maxRightDistance), t.maxRightDistance
if rpos < 0 {
rlen = rlen + int(rpos)
rpos = 0
}
} else {
lpos, llen = st.offset-int64(t.maxLeftDistance), t.maxLeftDistance
rpos, rlen = st.offset+int64(st.length), t.maxRightDistance
if lpos < 0 {
llen = llen + int(lpos)
lpos = 0
}
}
// the partials slice has a mirror entry for each of the testTree incompletes
partials := make([]partial, len(t.incomplete))
// test left (if there are valid left tests to try)
if checkl {
if st.reverse {
lslc, _ = buf.EofSlice(lpos, llen)
} else {
lslc, _ = buf.Slice(lpos, llen)
}
left := matchTestNodes(t.left, lslc, true)
for _, lp := range left {
if partials[lp.followUp].l {
partials[lp.followUp].ldistances = append(partials[lp.followUp].ldistances, lp.distances...)
} else {
partials[lp.followUp].l = true
partials[lp.followUp].ldistances = lp.distances
}
}
}
// test right (if there are valid right tests to try)
if checkr {
if st.reverse {
rslc, _ = buf.EofSlice(rpos, rlen)
} else {
rslc, _ = buf.Slice(rpos, rlen)
}
right := matchTestNodes(t.right, rslc, false)
for _, rp := range right {
if partials[rp.followUp].r {
partials[rp.followUp].rdistances = append(partials[rp.followUp].rdistances, rp.distances...)
} else {
partials[rp.followUp].r = true
partials[rp.followUp].rdistances = rp.distances
}
}
}
// now iterate through the partials, checking whether they fulfil any of the incompletes
for i, p := range partials {
if p.l == t.incomplete[i].l && p.r == t.incomplete[i].r {
kf := t.incomplete[i].kf
if b.keyFrames[kf[0]][kf[1]].check(st.offset) && waitSet.Check(kf[0]) {
if !p.l {
p.ldistances = []int{0}
}
if !p.r {
p.rdistances = []int{0}
}
if oneEnough(kf[1], b.keyFrames[kf[0]]) {
res = append(res, kfHit{kf, off - int64(p.ldistances[0]), p.ldistances[0] + st.length + p.rdistances[0]})
continue
}
for _, ldistance := range p.ldistances {
for _, rdistance := range p.rdistances {
res = append(res, kfHit{kf, off - int64(ldistance), ldistance + st.length + rdistance})
}
}
}
}
}
return res
}
applyKeyFrame := func(hit kfHit) (bool, string) {
kfs := b.keyFrames[hit.id[0]]
if len(kfs) == 1 {
return true, fmt.Sprintf("byte match at %d, %d", hit.offset, hit.length)
}
h, ok := hits[hit.id[0]]
if !ok {
h = newHit(hit.id[0])
}
if h.partials[hit.id[1]] == nil {
h.partials[hit.id[1]] = [][2]int64{{hit.offset, int64(hit.length)}}
} else {
h.partials[hit.id[1]] = append(h.partials[hit.id[1]], [2]int64{hit.offset, int64(hit.length)})
}
for _, p := range h.partials {
if p == nil {
return false, ""
}
}
prevOff := h.partials[0]
basis := make([][][2]int64, len(kfs))
basis[0] = prevOff
prevKf := kfs[0]
ok = false
for i, kf := range kfs[1:] {
var nextKf keyFrame
if i+2 < len(kfs) {
nextKf = kfs[i+2]
}
thisOff := h.partials[i+1]
prevOff, ok = kf.checkRelated(prevKf, nextKf, thisOff, prevOff)
if !ok {
return false, ""
}
basis[i+1] = prevOff
prevKf = kf
}
return true, fmt.Sprintf("byte match at %v", basis)
}
go func() {
for in := range incoming {
// if we've got a positive result, drain any remaining strikes from the matchers
if quitting {
continue
}
// if the strike reports progress, check if we should be continuing to wait
if in.idxa == -1 {
// update with the latest offset
if in.reverse {
eof = in.offset
} else {
bof = in.offset
}
w := waitSet.WaitingOnAt(bof, eof)
// if any of the waitlists are nil, we will continue - unless we are past the known bof and known eof (points at which we *should* have got at least partial matches), in which case we will check if any partial/potential matches are live
if w == nil {
// keep going if we don't have a maximum known bof, or if our current bof/eof are less than the maximum known bof/eof
if b.knownBOF < 0 || int64(b.knownBOF) > bof || int64(b.knownEOF) > eof {
continue
}
// if we don't have a waitlist, and we are past the known bof and known eof, grab all the partials and potentials to check if any are live
w = all(hits)
}
// exhausted all contenders, we can stop scanning
if !continueWaiting(w) {
quit()
}
continue
}
// now cache or satisfy the strike
var hasPotential bool
potentials := filterKF(b.tests[in.idxa+in.idxb].keyFrames(), waitSet)
for _, pot := range potentials {
// if any of the signatures are single keyframe we can satisfy immediately and skip cache
if len(b.keyFrames[pot[0]]) == 1 {
hasPotential = true
break
}
if hit, ok := hits[pot[0]]; ok && hit.potentiallyComplete(pot[1], strikes) {
hasPotential = true
break
}
}
if !hasPotential {
// cache the strike
s, ok := strikes[in.idxa+in.idxb]
if !ok {
s = &strikeItem{in, -1, nil}
strikes[in.idxa+in.idxb] = s
} else {
if s.successive == nil {
s.successive = make([][2]int64, 0, 10)
}
s.successive = append(s.successive, [2]int64{in.offset, int64(in.length)})
}
// range over the potentials, linking to the strike
for _, pot := range potentials {
if b.keyFrames[pot[0]][pot[1]].check(in.offset) {
hit, ok := hits[pot[0]]
if !ok {
hit = newHit(pot[0])
}
hit.potentialIdxs[pot[1]] = in.idxa + in.idxb + 1
}
}
goto end
}
// satisfy the strike
for {
ks := testStrike(in)
for _, k := range ks {
if match, basis := applyKeyFrame(k); match {
if waitSet.Check(k.id[0]) {
r <- result{k.id[0], basis}
if waitSet.PutAt(k.id[0], bof, eof) {
quit()
goto end
}
}
if h, ok := hits[k.id[0]]; ok {
h.matched = true
}
}
}
potentials = filterKF(potentials, waitSet)
var ok bool
for _, pot := range potentials {
in, ok = hits[pot[0]].nextPotential(strikes)
if ok {
break
}
}
if !ok {
break
}
}
end: // keep looping until incoming is closed
}
close(r)
}()
return incoming
}