buffer: optimize write()

PR-URL: #12361 Reviewed-By: James M Snell <[email protected]> Reviewed-By: Anna Henningsen <[email protected]>

Author: mscdex

benchmark/buffers/buffer-write-string.js

@@ -0,0 +1,70 @@
+'use strict';
+
+constcommon=require('../common.js');
+constbench=common.createBenchmark(main,{
+encoding: [
+'','utf8','ascii','hex','UCS-2','utf16le','latin1','binary'
+],
+args: ['','offset','offset+length'],
+len: [10,2048],
+n: [1e7]
+});
+
+functionmain(conf){
+constlen=+conf.len;
+constn=+conf.n;
+constencoding=conf.encoding;
+constargs=conf.args;
+
+conststring='a'.repeat(len);
+constbuf=Buffer.allocUnsafe(len);
+
+vari;
+
+switch(args){
+case'offset':
+if(encoding){
+bench.start();
+for(i=0;i<n;++i){
+buf.write(string,0,encoding);
+}
+bench.end(n);
+}else{
+bench.start();
+for(i=0;i<n;++i){
+buf.write(string,0);
+}
+bench.end(n);
+}
+break;
+case'offset+length':
+if(encoding){
+bench.start();
+for(i=0;i<n;++i){
+buf.write(string,0,buf.length,encoding);
+}
+bench.end(n);
+}else{
+bench.start();
+for(i=0;i<n;++i){
+buf.write(string,0,buf.length);
+}
+bench.end(n);
+}
+break;
+default:
+if(encoding){
+bench.start();
+for(i=0;i<n;++i){
+buf.write(string,encoding);
+}
+bench.end(n);
+}else{
+bench.start();
+for(i=0;i<n;++i){
+buf.write(string);
+}
+bench.end(n);
+}
+}
+}

lib/buffer.js

@@ -728,9 +728,7 @@ Buffer.prototype.fill = function fill(val, start, end, encoding){
 Buffer.prototype.write=function(string,offset,length,encoding){
 // Buffer#write(string);
 if(offset===undefined){
-encoding='utf8';
-length=this.length;
-offset=0;
+returnthis.utf8Write(string,0,this.length);
 
 // Buffer#write(string, encoding)
 }elseif(length===undefined&&typeofoffset==='string'){
@@ -743,12 +741,17 @@ Buffer.prototype.write = function(string, offset, length, encoding){
 offset=offset>>>0;
 if(isFinite(length)){
 length=length>>>0;
-if(encoding===undefined)
-encoding='utf8';
 }else{
 encoding=length;
 length=undefined;
 }
+
+varremaining=this.length-offset;
+if(length===undefined||length>remaining)
+length=remaining;
+
+if(string.length>0&&(length<0||offset<0))
+thrownewRangeError('Attempt to write outside buffer bounds');
 }else{
 // if someone is still calling the obsolete form of write(), tell them.
 // we don't want eg buf.write("foo", "utf8", 10) to silently turn into
@@ -757,50 +760,51 @@ Buffer.prototype.write = function(string, offset, length, encoding){
 'is no longer supported');
 }
 
-varremaining=this.length-offset;
-if(length===undefined||length>remaining)
-length=remaining;
-
-if(string.length>0&&(length<0||offset<0))
-thrownewRangeError('Attempt to write outside buffer bounds');
-
-if(!encoding)
-encoding='utf8';
-
-varloweredCase=false;
-for(;;){
-switch(encoding){
-case'hex':
-returnthis.hexWrite(string,offset,length);
-
-case'utf8':
-case'utf-8':
-returnthis.utf8Write(string,offset,length);
-
-case'ascii':
-returnthis.asciiWrite(string,offset,length);
-
-case'latin1':
-case'binary':
+if(!encoding)returnthis.utf8Write(string,offset,length);
+
+encoding+='';
+switch(encoding.length){
+case4:
+if(encoding==='utf8')returnthis.utf8Write(string,offset,length);
+if(encoding==='ucs2')returnthis.ucs2Write(string,offset,length);
+encoding=encoding.toLowerCase();
+if(encoding==='utf8')returnthis.utf8Write(string,offset,length);
+if(encoding==='ucs2')returnthis.ucs2Write(string,offset,length);
+break;
+case5:
+if(encoding==='utf-8')returnthis.utf8Write(string,offset,length);
+if(encoding==='ascii')returnthis.asciiWrite(string,offset,length);
+if(encoding==='ucs-2')returnthis.ucs2Write(string,offset,length);
+encoding=encoding.toLowerCase();
+if(encoding==='utf-8')returnthis.utf8Write(string,offset,length);
+if(encoding==='ascii')returnthis.asciiWrite(string,offset,length);
+if(encoding==='ucs-2')returnthis.ucs2Write(string,offset,length);
+break;
+case7:
+if(encoding==='utf16le'||encoding.toLowerCase()==='utf16le')
+returnthis.ucs2Write(string,offset,length);
+break;
+case8:
+if(encoding==='utf-16le'||encoding.toLowerCase()==='utf-16le')
+returnthis.ucs2Write(string,offset,length);
+break;
+case6:
+if(encoding==='latin1'||encoding==='binary')
 returnthis.latin1Write(string,offset,length);
-
-case'base64':
-// Warning: maxLength not taken into account in base64Write
+if(encoding==='base64')
 returnthis.base64Write(string,offset,length);
-
-case'ucs2':
-case'ucs-2':
-case'utf16le':
-case'utf-16le':
-returnthis.ucs2Write(string,offset,length);
-
-default:
-if(loweredCase)
-thrownewTypeError('Unknown encoding: '+encoding);
-encoding=(''+encoding).toLowerCase();
-loweredCase=true;
-}
+encoding=encoding.toLowerCase();
+if(encoding==='latin1'||encoding==='binary')
+returnthis.latin1Write(string,offset,length);
+if(encoding==='base64')
+returnthis.base64Write(string,offset,length);
+break;
+case3:
+if(encoding==='hex'||encoding.toLowerCase()==='hex')
+returnthis.hexWrite(string,offset,length);
+break;
 }
+thrownewTypeError('Unknown encoding: '+encoding);
 };