buffer: speed up concat via TypedArray#set

PR-URL: #60399 Reviewed-By: Matteo Collina <[email protected]> Reviewed-By: Antoine du Hamel <[email protected]> Reviewed-By: Rafael Gonzaga <[email protected]>

Author: gurgunday

lib/buffer.js

@@ -242,7 +242,7 @@ function copyImpl(source, target, targetStart, sourceStart, sourceEnd){
 return_copyActual(source,target,targetStart,sourceStart,sourceEnd);
 }
 
-function_copyActual(source,target,targetStart,sourceStart,sourceEnd){
+function_copyActual(source,target,targetStart,sourceStart,sourceEnd,isUint8Copy=false){
 if(sourceEnd-sourceStart>target.byteLength-targetStart)
 sourceEnd=sourceStart+target.byteLength-targetStart;
 
@@ -254,7 +254,11 @@ function _copyActual(source, target, targetStart, sourceStart, sourceEnd){
 if(nb<=0)
 return0;
 
-_copy(source,target,targetStart,sourceStart,nb);
+if(sourceStart===0&&nb===sourceLen&&(isUint8Copy||isUint8Array(target))){
+TypedArrayPrototypeSet(target,source,targetStart);
+}else{
+_copy(source,target,targetStart,sourceStart,nb);
+}
 
 returnnb;
 }
@@ -612,7 +616,7 @@ Buffer.concat = function concat(list, length){
 thrownewERR_INVALID_ARG_TYPE(
 `list[${i}]`,['Buffer','Uint8Array'],list[i]);
 }
-pos+=_copyActual(buf,buffer,pos,0,buf.length);
+pos+=_copyActual(buf,buffer,pos,0,buf.length,true);
 }
 
 // Note: `length` is always equal to `buffer.length` at this point

test/parallel/test-buffer-concat.js

@@ -76,6 +76,13 @@ assert.throws(() =>{
 constrandom10=common.hasCrypto ?
 require('crypto').randomBytes(10) :
 Buffer.alloc(10,1);
+constderived18=Buffer.alloc(18);
+for(leti=0,j=0;i<18;i++){
+if(i<10)
+derived18[i]=random10[i];
+else
+derived18[i]=random10[j++];
+}
 constempty=Buffer.alloc(0);
 
 assert.notDeepStrictEqual(random10,empty);
@@ -85,6 +92,7 @@ assert.deepStrictEqual(Buffer.concat([], 100), empty);
 assert.deepStrictEqual(Buffer.concat([random10],0),empty);
 assert.deepStrictEqual(Buffer.concat([random10],10),random10);
 assert.deepStrictEqual(Buffer.concat([random10,random10],10),random10);
+assert.deepStrictEqual(Buffer.concat([random10,random10],18),derived18);
 assert.deepStrictEqual(Buffer.concat([empty,random10]),random10);
 assert.deepStrictEqual(Buffer.concat([random10,empty,empty]),random10);
 

test/parallel/test-buffer-copy.js

@@ -226,6 +226,23 @@ b.copy(c, 'not a valid offset');
 // Make sure this acted like a regular copy with `0` offset.
 assert.deepStrictEqual(c,b.slice(0,c.length));
 
+// Copy into a Uint16Array target; bytes are packed into 16-bit elements.
+{
+constx=newUint16Array(4);
+constbuf=Buffer.of(1,2,3,4);
+constcopied=buf.copy(x);
+assert.strictEqual(copied,4);
+assert.ok(xinstanceofUint16Array);
+constbytes=newUint8Array(x.buffer,x.byteOffset,4);
+assert.deepStrictEqual(Array.from(bytes),[1,2,3,4]);
+constremaining=newUint8Array(
+x.buffer,
+x.byteOffset+4,
+x.byteLength-4
+);
+assert.ok(remaining.every((b)=>b===0));
+}
+
 {
 c.fill('C');
 assert.throws(()=>{