Update

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

@@ -479,10 +479,13 @@ func (e *bestFastEncoder) Reset(d *dict, singleBlock bool) {
 	if d == nil {
 		return
 	}
+	dictChanged := d != e.lastDict
 	// Init or copy dict table
-	if len(e.dictTable) != len(e.table) || d.id != e.lastDictID {
+	if len(e.dictTable) != len(e.table) || dictChanged {
 		if len(e.dictTable) != len(e.table) {
 			e.dictTable = make([]prevEntry, len(e.table))
+		} else {
+			clear(e.dictTable)
 		}
 		end := int32(len(d.content)) - 8 + e.maxMatchOff
 		for i := e.maxMatchOff; i < end; i += 4 {
@@ -510,13 +513,14 @@ func (e *bestFastEncoder) Reset(d *dict, singleBlock bool) {
 				offset: i + 3,
 			}
 		}
-		e.lastDictID = d.id
 	}
 
-	// Init or copy dict table
-	if len(e.dictLongTable) != len(e.longTable) || d.id != e.lastDictID {
+	// Init or copy dict long table
+	if len(e.dictLongTable) != len(e.longTable) || dictChanged {
 		if len(e.dictLongTable) != len(e.longTable) {
 			e.dictLongTable = make([]prevEntry, len(e.longTable))
+		} else {
+			clear(e.dictLongTable)
 		}
 		if len(d.content) >= 8 {
 			cv := load6432(d.content, 0)
@@ -538,8 +542,8 @@ func (e *bestFastEncoder) Reset(d *dict, singleBlock bool) {
 				off++
 			}
 		}
-		e.lastDictID = d.id
 	}
+	e.lastDict = d
 	// Reset table to initial state
 	copy(e.longTable[:], e.dictLongTable)
 
@@ -547,3 +551,18 @@ func (e *bestFastEncoder) Reset(d *dict, singleBlock bool) {
 	// Reset table to initial state
 	copy(e.table[:], e.dictTable)
 }
+
+func (e *bestFastEncoder) ResetPrefix(prefix []byte) {
+	e.resetBasePrefix(prefix)
+	if len(prefix) < 8 {
+		return
+	}
+	end := e.cur + int32(len(prefix)) - 8
+	for i := e.cur; i < end; i++ {
+		cv := load6432(prefix, i-e.cur)
+		h := hashLen(cv, bestLongTableBits, bestLongLen)
+		e.longTable[h] = prevEntry{offset: i, prev: e.longTable[h].offset}
+		h0 := hashLen(cv, bestShortTableBits, bestShortLen)
+		e.table[h0] = prevEntry{offset: i, prev: e.table[h0].offset}
+	}
+}