From 238a9d59dfb23944b0c3e4a36fef8e421fb11e16 Mon Sep 17 00:00:00 2001
From: "Kamat, Trivikram" <16024985+trivikr@users.noreply.github.com>
Date: Thu, 7 Nov 2024 23:29:17 +0000
Subject: [PATCH] feat(middleware-flexible-checksums): use Node.js native CRC32
 checksum API

---
 .../package.json                              |  4 +++
 ...tCrc32ChecksumAlgorithmFunction.browser.ts |  3 ++
 .../src/getCrc32ChecksumAlgorithmFunction.ts  | 28 +++++++++++++++++++
 yarn.lock                                     |  2 +-
 4 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 packages/middleware-flexible-checksums/src/getCrc32ChecksumAlgorithmFunction.browser.ts
 create mode 100644 packages/middleware-flexible-checksums/src/getCrc32ChecksumAlgorithmFunction.ts

diff --git a/packages/middleware-flexible-checksums/package.json b/packages/middleware-flexible-checksums/package.json
index b929c541b01b..c26fe92c2665 100644
--- a/packages/middleware-flexible-checksums/package.json
+++ b/packages/middleware-flexible-checksums/package.json
@@ -17,10 +17,13 @@
   "main": "./dist-cjs/index.js",
   "module": "./dist-es/index.js",
   "browser": {
+    "./dist-es/getCrc32ChecksumAlgorithmFunction": "./dist-es/getCrc32ChecksumAlgorithmFunction.browser",
     "./dist-es/streams/create-read-stream-on-buffer": "./dist-es/streams/create-read-stream-on-buffer.browser"
   },
   "react-native": {
+    "./dist-es/getCrc32ChecksumAlgorithmFunction": "./dist-es/getCrc32ChecksumAlgorithmFunction.browser",
     "./dist-es/streams/create-read-stream-on-buffer": "./dist-es/streams/create-read-stream-on-buffer.browser",
+    "./dist-cjs/getCrc32ChecksumAlgorithmFunction": "./dist-cjs/getCrc32ChecksumAlgorithmFunction.browser",
     "./dist-cjs/streams/create-read-stream-on-buffer": "./dist-cjs/streams/create-read-stream-on-buffer.browser"
   },
   "types": "./dist-types/index.d.ts",
@@ -32,6 +35,7 @@
   "dependencies": {
     "@aws-crypto/crc32": "5.2.0",
     "@aws-crypto/crc32c": "5.2.0",
+    "@aws-crypto/util": "5.2.0",
     "@aws-sdk/core": "*",
     "@aws-sdk/types": "*",
     "@smithy/is-array-buffer": "^3.0.0",
diff --git a/packages/middleware-flexible-checksums/src/getCrc32ChecksumAlgorithmFunction.browser.ts b/packages/middleware-flexible-checksums/src/getCrc32ChecksumAlgorithmFunction.browser.ts
new file mode 100644
index 000000000000..1c482b41706c
--- /dev/null
+++ b/packages/middleware-flexible-checksums/src/getCrc32ChecksumAlgorithmFunction.browser.ts
@@ -0,0 +1,3 @@
+import { AwsCrc32 } from "@aws-crypto/crc32";
+
+export const getCrc32ChecksumAlgorithmFunction = () => AwsCrc32;
diff --git a/packages/middleware-flexible-checksums/src/getCrc32ChecksumAlgorithmFunction.ts b/packages/middleware-flexible-checksums/src/getCrc32ChecksumAlgorithmFunction.ts
new file mode 100644
index 000000000000..8d38987a975f
--- /dev/null
+++ b/packages/middleware-flexible-checksums/src/getCrc32ChecksumAlgorithmFunction.ts
@@ -0,0 +1,28 @@
+import { AwsCrc32 } from "@aws-crypto/crc32";
+import { numToUint8 } from "@aws-crypto/util";
+import { Checksum } from "@smithy/types";
+import zlib from "zlib";
+
+export const getCrc32ChecksumAlgorithmFunction = () => {
+  // @ts-expect-error crc32 is defined only for Node.js >v20.15.0+ and >v22.2.0+.
+  if (typeof zlib.crc32 === "undefined") {
+    return AwsCrc32;
+  }
+
+  return class NodeCrc32 implements Checksum {
+    private checksum = 0;
+
+    update(data: Uint8Array) {
+      // @ts-expect-error crc32 is defined only for Node.js >v20.15.0+ and >v22.2.0+.
+      this.checksum = zlib.crc32(data, this.checksum);
+    }
+
+    async digest() {
+      return numToUint8(this.checksum);
+    }
+
+    reset() {
+      this.checksum = 0;
+    }
+  };
+};
diff --git a/yarn.lock b/yarn.lock
index cecbf306d72d..5c0b0a027605 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -74,7 +74,7 @@
   dependencies:
     tslib "^2.6.2"
 
-"@aws-crypto/util@^5.2.0":
+"@aws-crypto/util@5.2.0", "@aws-crypto/util@^5.2.0":
   version "5.2.0"
   resolved "https://registry.npmjs.org/@aws-crypto/util/-/util-5.2.0.tgz"
   integrity sha512-4RkU9EsI6ZpBve5fseQlGNUWKMa1RLPQ1dnjnQoe07ldfIzcsGb5hC5W0Dm7u423KWzawlrpbjXBrXCEv9zazQ==