Update

vendor/github.com/klauspost/compress/zstd/enc_base.go

@@ -21,7 +21,7 @@ type fastBase struct {
 	crc         *xxhash.Digest
 	tmp         [8]byte
 	blk         *blockEnc
-	lastDictID  uint32
+	lastDict    *dict
 	lowMem      bool
 }
 
@@ -128,6 +128,34 @@ func (e *fastBase) matchlen(s, t int32, src []byte) int32 {
 	return int32(matchLen(src[s:], src[t:]))
 }
 
+// resetBasePrefix resets the encoder state and loads prefix as initial history.
+// This is used for parallel job encoding where non-first jobs need overlap context.
+// Rep offsets are set to defaults [1,4,8] (invalidated, matching C behavior).
+func (e *fastBase) resetBasePrefix(prefix []byte) {
+	if e.blk == nil {
+		e.blk = &blockEnc{lowMem: e.lowMem}
+		e.blk.init()
+	} else {
+		e.blk.reset(nil)
+	}
+	e.blk.initNewEncode()
+	if e.crc == nil {
+		e.crc = xxhash.New()
+	} else {
+		e.crc.Reset()
+	}
+	e.blk.dictLitEnc = nil
+	e.ensureHist(len(prefix) + maxCompressedBlockSize)
+	// Bump cur so old table entries fall outside the window.
+	// When cur >= bufferReset, leave it; the first Encode call
+	// will shift/clear tables, preserving valid prefix entries.
+	if e.cur < e.bufferReset {
+		e.cur += e.maxMatchOff + int32(len(e.hist))
+	}
+	e.hist = e.hist[:0]
+	e.hist = append(e.hist, prefix...)
+}
+
 // Reset the encoding table.
 func (e *fastBase) resetBase(d *dict, singleBlock bool) {
 	if e.blk == nil {