buffer: faster integer argument check

ronag · ronag · commit 1cdad69903ca · 2024-07-29T00:23:05.000+02:00
diff --git a/lib/buffer.js b/lib/buffer.js
@@ -30,6 +30,7 @@ const {
   MathFloor,
   MathMin,
   MathTrunc,
+  NumberIsInteger,
   NumberIsNaN,
   NumberMAX_SAFE_INTEGER,
   NumberMIN_SAFE_INTEGER,
@@ -212,30 +213,27 @@ function _copy(source, target, targetStart, sourceStart, sourceEnd) {
   if (targetStart === undefined) {
     targetStart = 0;
   } else {
-    targetStart = toInteger(targetStart, 0);
+    targetStart = NumberIsInteger(targetStart) ? targetStart : toInteger(targetStart, 0);
     if (targetStart < 0)
       throw new ERR_OUT_OF_RANGE('targetStart', '>= 0', targetStart);
   }
 
   if (sourceStart === undefined) {
     sourceStart = 0;
   } else {
-    sourceStart = toInteger(sourceStart, 0);
+    sourceStart = NumberIsInteger(targetStart) ? targetStart : toInteger(sourceStart, 0);
     if (sourceStart < 0 || sourceStart > source.length)
       throw new ERR_OUT_OF_RANGE('sourceStart', `>= 0 && <= ${source.length}`, sourceStart);
   }
 
   if (sourceEnd === undefined) {
     sourceEnd = source.length;
   } else {
-    sourceEnd = toInteger(sourceEnd, 0);
+    sourceEnd = NumberIsInteger(sourceEnd) ? sourceEnd : toInteger(sourceEnd, 0);
     if (sourceEnd < 0)
       throw new ERR_OUT_OF_RANGE('sourceEnd', '>= 0', sourceEnd);
   }
 
-  if (targetStart >= target.length || sourceStart >= sourceEnd)
-    return 0;
-
   return _copyActual(source, target, targetStart, sourceStart, sourceEnd);
 }
 
@@ -248,6 +246,9 @@ function _copyActual(source, target, targetStart, sourceStart, sourceEnd) {
   if (nb > sourceLen)
     nb = sourceLen;
 
+  if (nb === 0)
+    return 0;
+
   if (sourceStart !== 0 || sourceEnd < source.length)
     source = new Uint8Array(source.buffer, source.byteOffset + sourceStart, nb);
 
