Update

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

@@ -1096,16 +1096,33 @@ func (e *betterFastEncoder) Reset(d *dict, singleBlock bool) {
 	}
 }
 
+func (e *betterFastEncoder) 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 += 2 {
+		cv := load6432(prefix, i-e.cur)
+		h := hashLen(cv, betterLongTableBits, betterLongLen)
+		e.longTable[h] = prevEntry{offset: i, prev: e.longTable[h].offset}
+		e.table[hashLen(cv>>8, betterShortTableBits, betterShortLen)] = tableEntry{val: uint32(cv >> 8), offset: i + 1}
+	}
+}
+
 // ResetDict will reset and set a dictionary if not nil
 func (e *betterFastEncoderDict) Reset(d *dict, singleBlock bool) {
 	e.resetBase(d, singleBlock)
 	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([]tableEntry, len(e.table))
+		} else {
+			clear(e.dictTable)
 		}
 		end := int32(len(d.content)) - 8 + e.maxMatchOff
 		for i := e.maxMatchOff; i < end; i += 4 {
@@ -1133,14 +1150,15 @@ func (e *betterFastEncoderDict) Reset(d *dict, singleBlock bool) {
 				offset: i + 3,
 			}
 		}
-		e.lastDictID = d.id
 		e.allDirty = true
 	}
 
-	// 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)
@@ -1162,9 +1180,9 @@ func (e *betterFastEncoderDict) Reset(d *dict, singleBlock bool) {
 				off++
 			}
 		}
-		e.lastDictID = d.id
 		e.allDirty = true
 	}
+	e.lastDict = d
 
 	// Reset table to initial state
 	{
@@ -1225,6 +1243,10 @@ func (e *betterFastEncoderDict) Reset(d *dict, singleBlock bool) {
 	e.allDirty = false
 }
 
+func (e *betterFastEncoderDict) ResetPrefix([]byte) {
+	panic("ResetPrefix not supported for dict encoders")
+}
+
 func (e *betterFastEncoderDict) markLongShardDirty(entryNum uint32) {
 	e.longTableShardDirty[entryNum/betterLongTableShardSize] = true
 }