[VOL-1386] This commit add "dep" as the package management tool
for voltha-go.
Change-Id: I52bc4911dd00a441756ec7c30f46d45091f3f90e
diff --git a/vendor/github.com/pierrec/lz4/block.go b/vendor/github.com/pierrec/lz4/block.go
new file mode 100644
index 0000000..00b1111
--- /dev/null
+++ b/vendor/github.com/pierrec/lz4/block.go
@@ -0,0 +1,397 @@
+package lz4
+
+import (
+ "encoding/binary"
+ "errors"
+)
+
+var (
+ // ErrInvalidSourceShortBuffer is returned by UncompressBlock or CompressBLock when a compressed
+ // block is corrupted or the destination buffer is not large enough for the uncompressed data.
+ ErrInvalidSourceShortBuffer = errors.New("lz4: invalid source or destination buffer too short")
+ // ErrInvalid is returned when reading an invalid LZ4 archive.
+ ErrInvalid = errors.New("lz4: bad magic number")
+)
+
+// blockHash hashes 4 bytes into a value < winSize.
+func blockHash(x uint32) uint32 {
+ const hasher uint32 = 2654435761 // Knuth multiplicative hash.
+ return x * hasher >> hashShift
+}
+
+// CompressBlockBound returns the maximum size of a given buffer of size n, when not compressible.
+func CompressBlockBound(n int) int {
+ return n + n/255 + 16
+}
+
+// UncompressBlock uncompresses the source buffer into the destination one,
+// and returns the uncompressed size.
+//
+// The destination buffer must be sized appropriately.
+//
+// An error is returned if the source data is invalid or the destination buffer is too small.
+func UncompressBlock(src, dst []byte) (si int, err error) {
+ defer func() {
+ // It is now faster to let the runtime panic and recover on out of bound slice access
+ // than checking indices as we go along.
+ if recover() != nil {
+ err = ErrInvalidSourceShortBuffer
+ }
+ }()
+ sn := len(src)
+ if sn == 0 {
+ return 0, nil
+ }
+ var di int
+
+ for {
+ // Literals and match lengths (token).
+ b := int(src[si])
+ si++
+
+ // Literals.
+ if lLen := b >> 4; lLen > 0 {
+ if lLen == 0xF {
+ for src[si] == 0xFF {
+ lLen += 0xFF
+ si++
+ }
+ lLen += int(src[si])
+ si++
+ }
+ i := si
+ si += lLen
+ di += copy(dst[di:], src[i:si])
+
+ if si >= sn {
+ return di, nil
+ }
+ }
+
+ si++
+ _ = src[si] // Bound check elimination.
+ offset := int(src[si-1]) | int(src[si])<<8
+ si++
+
+ // Match.
+ mLen := b & 0xF
+ if mLen == 0xF {
+ for src[si] == 0xFF {
+ mLen += 0xFF
+ si++
+ }
+ mLen += int(src[si])
+ si++
+ }
+ mLen += minMatch
+
+ // Copy the match.
+ i := di - offset
+ if offset > 0 && mLen >= offset {
+ // Efficiently copy the match dst[di-offset:di] into the dst slice.
+ bytesToCopy := offset * (mLen / offset)
+ expanded := dst[i:]
+ for n := offset; n <= bytesToCopy+offset; n *= 2 {
+ copy(expanded[n:], expanded[:n])
+ }
+ di += bytesToCopy
+ mLen -= bytesToCopy
+ }
+ di += copy(dst[di:], dst[i:i+mLen])
+ }
+}
+
+// CompressBlock compresses the source buffer into the destination one.
+// This is the fast version of LZ4 compression and also the default one.
+// The size of hashTable must be at least 64Kb.
+//
+// The size of the compressed data is returned. If it is 0 and no error, then the data is incompressible.
+//
+// An error is returned if the destination buffer is too small.
+func CompressBlock(src, dst []byte, hashTable []int) (di int, err error) {
+ defer func() {
+ if recover() != nil {
+ err = ErrInvalidSourceShortBuffer
+ }
+ }()
+
+ sn, dn := len(src)-mfLimit, len(dst)
+ if sn <= 0 || dn == 0 {
+ return 0, nil
+ }
+ var si int
+
+ // Fast scan strategy: the hash table only stores the last 4 bytes sequences.
+ // const accInit = 1 << skipStrength
+
+ anchor := si // Position of the current literals.
+ // acc := accInit // Variable step: improves performance on non-compressible data.
+
+ for si < sn {
+ // Hash the next 4 bytes (sequence)...
+ match := binary.LittleEndian.Uint32(src[si:])
+ h := blockHash(match)
+
+ ref := hashTable[h]
+ hashTable[h] = si
+ if ref >= sn { // Invalid reference (dirty hashtable).
+ si++
+ continue
+ }
+ offset := si - ref
+ if offset <= 0 || offset >= winSize || // Out of window.
+ match != binary.LittleEndian.Uint32(src[ref:]) { // Hash collision on different matches.
+ // si += acc >> skipStrength
+ // acc++
+ si++
+ continue
+ }
+
+ // Match found.
+ // acc = accInit
+ lLen := si - anchor // Literal length.
+
+ // Encode match length part 1.
+ si += minMatch
+ mLen := si // Match length has minMatch already.
+ // Find the longest match, first looking by batches of 8 bytes.
+ for si < sn && binary.LittleEndian.Uint64(src[si:]) == binary.LittleEndian.Uint64(src[si-offset:]) {
+ si += 8
+ }
+ // Then byte by byte.
+ for si < sn && src[si] == src[si-offset] {
+ si++
+ }
+
+ mLen = si - mLen
+ if mLen < 0xF {
+ dst[di] = byte(mLen)
+ } else {
+ dst[di] = 0xF
+ }
+
+ // Encode literals length.
+ if lLen < 0xF {
+ dst[di] |= byte(lLen << 4)
+ } else {
+ dst[di] |= 0xF0
+ di++
+ l := lLen - 0xF
+ for ; l >= 0xFF; l -= 0xFF {
+ dst[di] = 0xFF
+ di++
+ }
+ dst[di] = byte(l)
+ }
+ di++
+
+ // Literals.
+ copy(dst[di:], src[anchor:anchor+lLen])
+ di += lLen + 2
+ anchor = si
+
+ // Encode offset.
+ _ = dst[di] // Bound check elimination.
+ dst[di-2], dst[di-1] = byte(offset), byte(offset>>8)
+
+ // Encode match length part 2.
+ if mLen >= 0xF {
+ for mLen -= 0xF; mLen >= 0xFF; mLen -= 0xFF {
+ dst[di] = 0xFF
+ di++
+ }
+ dst[di] = byte(mLen)
+ di++
+ }
+ }
+
+ if anchor == 0 {
+ // Incompressible.
+ return 0, nil
+ }
+
+ // Last literals.
+ lLen := len(src) - anchor
+ if lLen < 0xF {
+ dst[di] = byte(lLen << 4)
+ } else {
+ dst[di] = 0xF0
+ di++
+ for lLen -= 0xF; lLen >= 0xFF; lLen -= 0xFF {
+ dst[di] = 0xFF
+ di++
+ }
+ dst[di] = byte(lLen)
+ }
+ di++
+
+ // Write the last literals.
+ if di >= anchor {
+ // Incompressible.
+ return 0, nil
+ }
+ di += copy(dst[di:], src[anchor:])
+ return di, nil
+}
+
+// CompressBlockHC compresses the source buffer src into the destination dst
+// with max search depth (use 0 or negative value for no max).
+//
+// CompressBlockHC compression ratio is better than CompressBlock but it is also slower.
+//
+// The size of the compressed data is returned. If it is 0 and no error, then the data is not compressible.
+//
+// An error is returned if the destination buffer is too small.
+func CompressBlockHC(src, dst []byte, depth int) (di int, err error) {
+ defer func() {
+ if recover() != nil {
+ err = ErrInvalidSourceShortBuffer
+ }
+ }()
+
+ sn, dn := len(src)-mfLimit, len(dst)
+ if sn <= 0 || dn == 0 {
+ return 0, nil
+ }
+ var si int
+
+ // hashTable: stores the last position found for a given hash
+ // chaingTable: stores previous positions for a given hash
+ var hashTable, chainTable [winSize]int
+
+ if depth <= 0 {
+ depth = winSize
+ }
+
+ anchor := si
+ for si < sn {
+ // Hash the next 4 bytes (sequence).
+ match := binary.LittleEndian.Uint32(src[si:])
+ h := blockHash(match)
+
+ // Follow the chain until out of window and give the longest match.
+ mLen := 0
+ offset := 0
+ for next, try := hashTable[h], depth; try > 0 && next > 0 && si-next < winSize; next = chainTable[next&winMask] {
+ // The first (mLen==0) or next byte (mLen>=minMatch) at current match length
+ // must match to improve on the match length.
+ if src[next+mLen] != src[si+mLen] {
+ continue
+ }
+ ml := 0
+ // Compare the current position with a previous with the same hash.
+ for ml < sn-si && binary.LittleEndian.Uint64(src[next+ml:]) == binary.LittleEndian.Uint64(src[si+ml:]) {
+ ml += 8
+ }
+ for ml < sn-si && src[next+ml] == src[si+ml] {
+ ml++
+ }
+ if ml < minMatch || ml <= mLen {
+ // Match too small (<minMath) or smaller than the current match.
+ continue
+ }
+ // Found a longer match, keep its position and length.
+ mLen = ml
+ offset = si - next
+ // Try another previous position with the same hash.
+ try--
+ }
+ chainTable[si&winMask] = hashTable[h]
+ hashTable[h] = si
+
+ // No match found.
+ if mLen == 0 {
+ si++
+ continue
+ }
+
+ // Match found.
+ // Update hash/chain tables with overlapping bytes:
+ // si already hashed, add everything from si+1 up to the match length.
+ winStart := si + 1
+ if ws := si + mLen - winSize; ws > winStart {
+ winStart = ws
+ }
+ for si, ml := winStart, si+mLen; si < ml; {
+ match >>= 8
+ match |= uint32(src[si+3]) << 24
+ h := blockHash(match)
+ chainTable[si&winMask] = hashTable[h]
+ hashTable[h] = si
+ si++
+ }
+
+ lLen := si - anchor
+ si += mLen
+ mLen -= minMatch // Match length does not include minMatch.
+
+ if mLen < 0xF {
+ dst[di] = byte(mLen)
+ } else {
+ dst[di] = 0xF
+ }
+
+ // Encode literals length.
+ if lLen < 0xF {
+ dst[di] |= byte(lLen << 4)
+ } else {
+ dst[di] |= 0xF0
+ di++
+ l := lLen - 0xF
+ for ; l >= 0xFF; l -= 0xFF {
+ dst[di] = 0xFF
+ di++
+ }
+ dst[di] = byte(l)
+ }
+ di++
+
+ // Literals.
+ copy(dst[di:], src[anchor:anchor+lLen])
+ di += lLen
+ anchor = si
+
+ // Encode offset.
+ di += 2
+ dst[di-2], dst[di-1] = byte(offset), byte(offset>>8)
+
+ // Encode match length part 2.
+ if mLen >= 0xF {
+ for mLen -= 0xF; mLen >= 0xFF; mLen -= 0xFF {
+ dst[di] = 0xFF
+ di++
+ }
+ dst[di] = byte(mLen)
+ di++
+ }
+ }
+
+ if anchor == 0 {
+ // Incompressible.
+ return 0, nil
+ }
+
+ // Last literals.
+ lLen := len(src) - anchor
+ if lLen < 0xF {
+ dst[di] = byte(lLen << 4)
+ } else {
+ dst[di] = 0xF0
+ di++
+ lLen -= 0xF
+ for ; lLen >= 0xFF; lLen -= 0xFF {
+ dst[di] = 0xFF
+ di++
+ }
+ dst[di] = byte(lLen)
+ }
+ di++
+
+ // Write the last literals.
+ if di >= anchor {
+ // Incompressible.
+ return 0, nil
+ }
+ di += copy(dst[di:], src[anchor:])
+ return di, nil
+}