mirror of
https://github.com/cwinfo/matterbridge.git
synced 2024-11-27 02:01:35 +00:00
300 lines
7.5 KiB
Go
300 lines
7.5 KiB
Go
//go:build !amd64 || appengine || !gc || noasm
|
|
// +build !amd64 appengine !gc noasm
|
|
|
|
// This file contains a generic implementation of Decoder.Decompress4X.
|
|
package huff0
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
)
|
|
|
|
// Decompress4X will decompress a 4X encoded stream.
|
|
// The length of the supplied input must match the end of a block exactly.
|
|
// The *capacity* of the dst slice must match the destination size of
|
|
// the uncompressed data exactly.
|
|
func (d *Decoder) Decompress4X(dst, src []byte) ([]byte, error) {
|
|
if len(d.dt.single) == 0 {
|
|
return nil, errors.New("no table loaded")
|
|
}
|
|
if len(src) < 6+(4*1) {
|
|
return nil, errors.New("input too small")
|
|
}
|
|
if use8BitTables && d.actualTableLog <= 8 {
|
|
return d.decompress4X8bit(dst, src)
|
|
}
|
|
|
|
var br [4]bitReaderShifted
|
|
// Decode "jump table"
|
|
start := 6
|
|
for i := 0; i < 3; i++ {
|
|
length := int(src[i*2]) | (int(src[i*2+1]) << 8)
|
|
if start+length >= len(src) {
|
|
return nil, errors.New("truncated input (or invalid offset)")
|
|
}
|
|
err := br[i].init(src[start : start+length])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
start += length
|
|
}
|
|
err := br[3].init(src[start:])
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// destination, offset to match first output
|
|
dstSize := cap(dst)
|
|
dst = dst[:dstSize]
|
|
out := dst
|
|
dstEvery := (dstSize + 3) / 4
|
|
|
|
const tlSize = 1 << tableLogMax
|
|
const tlMask = tlSize - 1
|
|
single := d.dt.single[:tlSize]
|
|
|
|
// Use temp table to avoid bound checks/append penalty.
|
|
buf := d.buffer()
|
|
var off uint8
|
|
var decoded int
|
|
|
|
// Decode 2 values from each decoder/loop.
|
|
const bufoff = 256
|
|
for {
|
|
if br[0].off < 4 || br[1].off < 4 || br[2].off < 4 || br[3].off < 4 {
|
|
break
|
|
}
|
|
|
|
{
|
|
const stream = 0
|
|
const stream2 = 1
|
|
br[stream].fillFast()
|
|
br[stream2].fillFast()
|
|
|
|
val := br[stream].peekBitsFast(d.actualTableLog)
|
|
val2 := br[stream2].peekBitsFast(d.actualTableLog)
|
|
v := single[val&tlMask]
|
|
v2 := single[val2&tlMask]
|
|
br[stream].advance(uint8(v.entry))
|
|
br[stream2].advance(uint8(v2.entry))
|
|
buf[stream][off] = uint8(v.entry >> 8)
|
|
buf[stream2][off] = uint8(v2.entry >> 8)
|
|
|
|
val = br[stream].peekBitsFast(d.actualTableLog)
|
|
val2 = br[stream2].peekBitsFast(d.actualTableLog)
|
|
v = single[val&tlMask]
|
|
v2 = single[val2&tlMask]
|
|
br[stream].advance(uint8(v.entry))
|
|
br[stream2].advance(uint8(v2.entry))
|
|
buf[stream][off+1] = uint8(v.entry >> 8)
|
|
buf[stream2][off+1] = uint8(v2.entry >> 8)
|
|
}
|
|
|
|
{
|
|
const stream = 2
|
|
const stream2 = 3
|
|
br[stream].fillFast()
|
|
br[stream2].fillFast()
|
|
|
|
val := br[stream].peekBitsFast(d.actualTableLog)
|
|
val2 := br[stream2].peekBitsFast(d.actualTableLog)
|
|
v := single[val&tlMask]
|
|
v2 := single[val2&tlMask]
|
|
br[stream].advance(uint8(v.entry))
|
|
br[stream2].advance(uint8(v2.entry))
|
|
buf[stream][off] = uint8(v.entry >> 8)
|
|
buf[stream2][off] = uint8(v2.entry >> 8)
|
|
|
|
val = br[stream].peekBitsFast(d.actualTableLog)
|
|
val2 = br[stream2].peekBitsFast(d.actualTableLog)
|
|
v = single[val&tlMask]
|
|
v2 = single[val2&tlMask]
|
|
br[stream].advance(uint8(v.entry))
|
|
br[stream2].advance(uint8(v2.entry))
|
|
buf[stream][off+1] = uint8(v.entry >> 8)
|
|
buf[stream2][off+1] = uint8(v2.entry >> 8)
|
|
}
|
|
|
|
off += 2
|
|
|
|
if off == 0 {
|
|
if bufoff > dstEvery {
|
|
d.bufs.Put(buf)
|
|
return nil, errors.New("corruption detected: stream overrun 1")
|
|
}
|
|
// There must at least be 3 buffers left.
|
|
if len(out)-bufoff < dstEvery*3 {
|
|
d.bufs.Put(buf)
|
|
return nil, errors.New("corruption detected: stream overrun 2")
|
|
}
|
|
//copy(out, buf[0][:])
|
|
//copy(out[dstEvery:], buf[1][:])
|
|
//copy(out[dstEvery*2:], buf[2][:])
|
|
//copy(out[dstEvery*3:], buf[3][:])
|
|
*(*[bufoff]byte)(out) = buf[0]
|
|
*(*[bufoff]byte)(out[dstEvery:]) = buf[1]
|
|
*(*[bufoff]byte)(out[dstEvery*2:]) = buf[2]
|
|
*(*[bufoff]byte)(out[dstEvery*3:]) = buf[3]
|
|
out = out[bufoff:]
|
|
decoded += bufoff * 4
|
|
}
|
|
}
|
|
if off > 0 {
|
|
ioff := int(off)
|
|
if len(out) < dstEvery*3+ioff {
|
|
d.bufs.Put(buf)
|
|
return nil, errors.New("corruption detected: stream overrun 3")
|
|
}
|
|
copy(out, buf[0][:off])
|
|
copy(out[dstEvery:], buf[1][:off])
|
|
copy(out[dstEvery*2:], buf[2][:off])
|
|
copy(out[dstEvery*3:], buf[3][:off])
|
|
decoded += int(off) * 4
|
|
out = out[off:]
|
|
}
|
|
|
|
// Decode remaining.
|
|
remainBytes := dstEvery - (decoded / 4)
|
|
for i := range br {
|
|
offset := dstEvery * i
|
|
endsAt := offset + remainBytes
|
|
if endsAt > len(out) {
|
|
endsAt = len(out)
|
|
}
|
|
br := &br[i]
|
|
bitsLeft := br.remaining()
|
|
for bitsLeft > 0 {
|
|
br.fill()
|
|
if offset >= endsAt {
|
|
d.bufs.Put(buf)
|
|
return nil, errors.New("corruption detected: stream overrun 4")
|
|
}
|
|
|
|
// Read value and increment offset.
|
|
val := br.peekBitsFast(d.actualTableLog)
|
|
v := single[val&tlMask].entry
|
|
nBits := uint8(v)
|
|
br.advance(nBits)
|
|
bitsLeft -= uint(nBits)
|
|
out[offset] = uint8(v >> 8)
|
|
offset++
|
|
}
|
|
if offset != endsAt {
|
|
d.bufs.Put(buf)
|
|
return nil, fmt.Errorf("corruption detected: short output block %d, end %d != %d", i, offset, endsAt)
|
|
}
|
|
decoded += offset - dstEvery*i
|
|
err = br.close()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
d.bufs.Put(buf)
|
|
if dstSize != decoded {
|
|
return nil, errors.New("corruption detected: short output block")
|
|
}
|
|
return dst, nil
|
|
}
|
|
|
|
// Decompress1X will decompress a 1X encoded stream.
|
|
// The cap of the output buffer will be the maximum decompressed size.
|
|
// The length of the supplied input must match the end of a block exactly.
|
|
func (d *Decoder) Decompress1X(dst, src []byte) ([]byte, error) {
|
|
if len(d.dt.single) == 0 {
|
|
return nil, errors.New("no table loaded")
|
|
}
|
|
if use8BitTables && d.actualTableLog <= 8 {
|
|
return d.decompress1X8Bit(dst, src)
|
|
}
|
|
var br bitReaderShifted
|
|
err := br.init(src)
|
|
if err != nil {
|
|
return dst, err
|
|
}
|
|
maxDecodedSize := cap(dst)
|
|
dst = dst[:0]
|
|
|
|
// Avoid bounds check by always having full sized table.
|
|
const tlSize = 1 << tableLogMax
|
|
const tlMask = tlSize - 1
|
|
dt := d.dt.single[:tlSize]
|
|
|
|
// Use temp table to avoid bound checks/append penalty.
|
|
bufs := d.buffer()
|
|
buf := &bufs[0]
|
|
var off uint8
|
|
|
|
for br.off >= 8 {
|
|
br.fillFast()
|
|
v := dt[br.peekBitsFast(d.actualTableLog)&tlMask]
|
|
br.advance(uint8(v.entry))
|
|
buf[off+0] = uint8(v.entry >> 8)
|
|
|
|
v = dt[br.peekBitsFast(d.actualTableLog)&tlMask]
|
|
br.advance(uint8(v.entry))
|
|
buf[off+1] = uint8(v.entry >> 8)
|
|
|
|
// Refill
|
|
br.fillFast()
|
|
|
|
v = dt[br.peekBitsFast(d.actualTableLog)&tlMask]
|
|
br.advance(uint8(v.entry))
|
|
buf[off+2] = uint8(v.entry >> 8)
|
|
|
|
v = dt[br.peekBitsFast(d.actualTableLog)&tlMask]
|
|
br.advance(uint8(v.entry))
|
|
buf[off+3] = uint8(v.entry >> 8)
|
|
|
|
off += 4
|
|
if off == 0 {
|
|
if len(dst)+256 > maxDecodedSize {
|
|
br.close()
|
|
d.bufs.Put(bufs)
|
|
return nil, ErrMaxDecodedSizeExceeded
|
|
}
|
|
dst = append(dst, buf[:]...)
|
|
}
|
|
}
|
|
|
|
if len(dst)+int(off) > maxDecodedSize {
|
|
d.bufs.Put(bufs)
|
|
br.close()
|
|
return nil, ErrMaxDecodedSizeExceeded
|
|
}
|
|
dst = append(dst, buf[:off]...)
|
|
|
|
// br < 8, so uint8 is fine
|
|
bitsLeft := uint8(br.off)*8 + 64 - br.bitsRead
|
|
for bitsLeft > 0 {
|
|
br.fill()
|
|
if false && br.bitsRead >= 32 {
|
|
if br.off >= 4 {
|
|
v := br.in[br.off-4:]
|
|
v = v[:4]
|
|
low := (uint32(v[0])) | (uint32(v[1]) << 8) | (uint32(v[2]) << 16) | (uint32(v[3]) << 24)
|
|
br.value = (br.value << 32) | uint64(low)
|
|
br.bitsRead -= 32
|
|
br.off -= 4
|
|
} else {
|
|
for br.off > 0 {
|
|
br.value = (br.value << 8) | uint64(br.in[br.off-1])
|
|
br.bitsRead -= 8
|
|
br.off--
|
|
}
|
|
}
|
|
}
|
|
if len(dst) >= maxDecodedSize {
|
|
d.bufs.Put(bufs)
|
|
br.close()
|
|
return nil, ErrMaxDecodedSizeExceeded
|
|
}
|
|
v := d.dt.single[br.peekBitsFast(d.actualTableLog)&tlMask]
|
|
nBits := uint8(v.entry)
|
|
br.advance(nBits)
|
|
bitsLeft -= nBits
|
|
dst = append(dst, uint8(v.entry>>8))
|
|
}
|
|
d.bufs.Put(bufs)
|
|
return dst, br.close()
|
|
}
|