From 6bbb59fc34d3d1a8ec03f424bb8e0d03b43065f9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=BCrg=C3=BCn=20Day=C4=B1o=C4=9Flu?= <hey@gurgun.day>
Date: Fri, 24 Oct 2025 23:26:21 +0200
Subject: [PATCH 1/2] buffer: inline copyImpl

---
 lib/buffer.js | 75 ++++++++++++++++++++++++---------------------------
 1 file changed, 35 insertions(+), 40 deletions(-)

diff --git a/lib/buffer.js b/lib/buffer.js
index c9f45d333886d3..a59b0942d88b18 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -204,42 +204,6 @@ function toInteger(n, defaultVal) {
   return defaultVal;
 }
 
-function copyImpl(source, target, targetStart, sourceStart, sourceEnd) {
-  if (!ArrayBufferIsView(source))
-    throw new ERR_INVALID_ARG_TYPE('source', ['Buffer', 'Uint8Array'], source);
-  if (!ArrayBufferIsView(target))
-    throw new ERR_INVALID_ARG_TYPE('target', ['Buffer', 'Uint8Array'], target);
-
-  if (targetStart === undefined) {
-    targetStart = 0;
-  } else {
-    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 = NumberIsInteger(sourceStart) ? sourceStart : toInteger(sourceStart, 0);
-    if (sourceStart < 0 || sourceStart > source.byteLength)
-      throw new ERR_OUT_OF_RANGE('sourceStart', `>= 0 && <= ${source.byteLength}`, sourceStart);
-  }
-
-  if (sourceEnd === undefined) {
-    sourceEnd = source.byteLength;
-  } else {
-    sourceEnd = NumberIsInteger(sourceEnd) ? sourceEnd : toInteger(sourceEnd, 0);
-    if (sourceEnd < 0)
-      throw new ERR_OUT_OF_RANGE('sourceEnd', '>= 0', sourceEnd);
-  }
-
-  if (targetStart >= target.byteLength || sourceStart >= sourceEnd)
-    return 0;
-
-  return _copyActual(source, target, targetStart, sourceStart, sourceEnd);
-}
-
 function _copyActual(source, target, targetStart, sourceStart, sourceEnd) {
   if (sourceEnd - sourceStart > target.byteLength - targetStart)
     sourceEnd = sourceStart + target.byteLength - targetStart;
@@ -821,10 +785,41 @@ ObjectDefineProperty(Buffer.prototype, 'offset', {
   },
 });
 
-Buffer.prototype.copy =
-  function copy(target, targetStart, sourceStart, sourceEnd) {
-    return copyImpl(this, target, targetStart, sourceStart, sourceEnd);
-  };
+Buffer.prototype.copy = function copy(target, targetStart, sourceStart, sourceEnd) {
+  if (!ArrayBufferIsView(this))
+    throw new ERR_INVALID_ARG_TYPE('source', ['Buffer', 'Uint8Array'], this);
+  if (!ArrayBufferIsView(target))
+    throw new ERR_INVALID_ARG_TYPE('target', ['Buffer', 'Uint8Array'], target);
+
+  if (targetStart === undefined) {
+    targetStart = 0;
+  } else {
+    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 = NumberIsInteger(sourceStart) ? sourceStart : toInteger(sourceStart, 0);
+    if (sourceStart < 0 || sourceStart > this.byteLength)
+      throw new ERR_OUT_OF_RANGE('sourceStart', `>= 0 && <= ${this.byteLength}`, sourceStart);
+  }
+
+  if (sourceEnd === undefined) {
+    sourceEnd = this.byteLength;
+  } else {
+    sourceEnd = NumberIsInteger(sourceEnd) ? sourceEnd : toInteger(sourceEnd, 0);
+    if (sourceEnd < 0)
+      throw new ERR_OUT_OF_RANGE('sourceEnd', '>= 0', sourceEnd);
+  }
+
+  if (targetStart >= target.byteLength || sourceStart >= sourceEnd)
+    return 0;
+
+  return _copyActual(this, target, targetStart, sourceStart, sourceEnd);
+};
 
 // No need to verify that "buf.length <= MAX_UINT32" since it's a read-only
 // property of a typed array.

From 1f9abbe342fb312344867f88e0f6561c1c2a7f24 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=BCrg=C3=BCn=20Day=C4=B1o=C4=9Flu?= <hey@gurgun.day>
Date: Sat, 25 Oct 2025 00:47:55 +0200
Subject: [PATCH 2/2] remove unnecessary check

---
 lib/buffer.js | 2 --
 1 file changed, 2 deletions(-)

diff --git a/lib/buffer.js b/lib/buffer.js
index a59b0942d88b18..4a26a5db9d83d0 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -786,8 +786,6 @@ ObjectDefineProperty(Buffer.prototype, 'offset', {
 });
 
 Buffer.prototype.copy = function copy(target, targetStart, sourceStart, sourceEnd) {
-  if (!ArrayBufferIsView(this))
-    throw new ERR_INVALID_ARG_TYPE('source', ['Buffer', 'Uint8Array'], this);
   if (!ArrayBufferIsView(target))
     throw new ERR_INVALID_ARG_TYPE('target', ['Buffer', 'Uint8Array'], target);