@nxtedition/slice - npm Package Compare versions

Comparing version 1.0.4 to 1.0.7

LICENSE

+MIT License
+
+Copyright (c) nxtedition
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

+# @nxtedition/slice
+
+A high-performance buffer slice and pool allocator for Node.js.
+
+## Why
+
+Node.js `Buffer.subarray()` is slow. Every call creates a new `Buffer` object — a typed array wrapper with prototype chain setup, internal slot initialization, and bounds validation. This overhead is negligible for occasional use, but becomes a bottleneck in hot paths — protocol parsers, binary codecs, streaming pipelines — where thousands of sub-views are created per second.
+
+`Buffer.allocUnsafe()` is worse. Allocations above the pool size (`Buffer.poolSize`) threshold go through `allocBuffer` which crosses into C++ to create a new `ArrayBuffer` backing store. The pooled fast path still involves bookkeeping and pool management overhead, and every allocation produces a new `Buffer` object that the GC must eventually collect.
+
+`Slice` avoids this entirely. It is a plain JavaScript object with `buffer`, `byteOffset`, and `byteLength` fields. Creating a slice is just setting three properties — no typed array wrapper creation, no GC pressure from short-lived `Buffer` objects. Operations like `toString`, `copy`, and `compare` delegate directly to the underlying buffer with the correct offsets.
+
+`PoolAllocator` takes this further. Like Node's internal pool, it has management overhead — but it rarely (if ever) allocates new backing stores, and because `Slice` is a plain object rather than a typed array, resizing or freeing a slice doesn't produce garbage for V8 to collect. It pre-allocates a large contiguous buffer and hands out regions using power-of-2 bucketing. When a slice is freed, its slot is recycled. When a slice is resized within the same bucket, no data moves at all — just a field update. This gives you `malloc`/`realloc`/`free` semantics with near-zero overhead per operation. The trade-off is upfront memory allocation and internal fragmentation from power-of-2 rounding — a 10-byte allocation uses a 16-byte slot. Buckets are also independent: a freed 16-byte slot cannot satisfy a 32-byte request, so the pool can become fragmented if allocation sizes are uneven. Use `stats` to monitor pool utilization and tune the pool size for your workload.
+
+## Install
+
+```sh
+npm install @nxtedition/slice
+```
+
+## Usage
+
+```js
+import { Slice, PoolAllocator } from '@nxtedition/slice'
+
+// Create a slice from an existing buffer
+const buf = Buffer.from('hello world')
+const slice = new Slice(buf, 6, 5)
+slice.toString() // 'world'
+
+// Use a pool allocator for high-throughput allocation
+const pool = new PoolAllocator()
+const s = new Slice()
+
+pool.realloc(s, 64) // allocate 64 bytes from pool
+s.write('hello')
+pool.realloc(s, 128) // grow — may reuse same slot
+pool.realloc(s, 0) // free — slot is recycled
+```
+
+## Benchmarks
+
+Measured on Apple M3 Pro, Node.js v25.3.0:
+
+### Allocation
+
+| Operation        | `Buffer.allocUnsafe` | `Buffer.allocUnsafeSlow` | `PoolAllocator` | Speedup |
+| ---------------- | -------------------- | ------------------------ | --------------- | ------- |
+| alloc 64 bytes   | 28.53 ns             | 31.33 ns                 | **3.87 ns**     | 7.4x    |
+| alloc 256 bytes  | 36.98 ns             | 170.56 ns                | **4.34 ns**     | 8.5x    |
+| alloc 1024 bytes | 65.48 ns             | 238.49 ns                | **4.36 ns**     | 15.0x   |
+| alloc 4096 bytes | 301.19 ns            | 292.50 ns                | **4.29 ns**     | 70.2x   |
+
+### Slice creation vs `Buffer.subarray`
+
+| Operation           | `Buffer.subarray` | `Slice`     | Speedup |
+| ------------------- | ----------------- | ----------- | ------- |
+| subarray 64 bytes   | 27.32 ns          | **9.68 ns** | 2.8x    |
+| subarray 1024 bytes | 26.75 ns          | **9.52 ns** | 2.8x    |
+
+### Combined operations
+
+| Operation                             | `Buffer.subarray` | `Slice`       | Speedup |
+| ------------------------------------- | ----------------- | ------------- | ------- |
+| subarray + toString (64 bytes)        | 78.89 ns          | **60.12 ns**  | 1.3x    |
+| alloc/free 64 bytes                   | 25.24 ns          | **22.82 ns**  | 1.1x    |
+| alloc/free 256 bytes                  | 34.07 ns          | **22.63 ns**  | 1.5x    |
+| realloc churn (64 → 128 → 64)         | 70.20 ns          | **20.80 ns**  | 3.4x    |
+| realloc in-place (grow within bucket) | 45.41 ns          | **8.28 ns**   | 5.5x    |
+| 10 concurrent allocs then free        | 312.96 ns         | **259.34 ns** | 1.2x    |
+
+## API
+
+### `Slice`
+
+A lightweight view over a `Buffer` with explicit offset and length tracking.
+
+#### `new Slice(buffer?: Buffer, byteOffset?: number, byteLength?: number, maxByteLength?: number)`
+
+Creates a new slice. All parameters are optional — defaults to an empty slice.
+
+#### Properties
+
+- `buffer: Buffer` — The underlying `Buffer`
+- `byteOffset: number` — Start offset into the buffer
+- `byteLength: number` — Current length in bytes
+- `maxByteLength: number` — Maximum capacity in bytes
+- `length: number` — Alias for `byteLength`
+
+#### Methods
+
+- `reset(): void` — Clear the slice back to empty state. **Note:** this does not return the slot to the `PoolAllocator` — you must call `realloc(slice, 0)` to free pool memory.
+- `copy(target: Buffer | Slice, targetStart?: number, sourceStart?: number, sourceEnd?: number): number` — Copy data to a `Buffer` or `Slice`. Returns bytes copied.
+- `compare(target: Buffer | Slice, targetStart?: number, targetEnd?: number, sourceStart?: number, sourceEnd?: number): -1 | 0 | 1` — Compare with a `Buffer` or `Slice`
+- `write(string: string, offset?: number, length?: number, encoding?: BufferEncoding): number` — Write a string into the slice. Returns bytes written.
+- `set(source: Buffer | Slice | null | undefined, offset?: number): void` — Copy from a `Buffer` or `Slice` into this slice
+- `at(index: number): number` — Read byte at index (supports negative indexing)
+- `test(expr: { test(buffer: Buffer, byteOffset: number, byteLength: number): boolean }): boolean` — Test the slice against an expression object
+- `toString(encoding?: BufferEncoding, start?: number, end?: number): string` — Convert to string
+- `toBuffer(start?: number, end?: number): Buffer` — Return a `Buffer` view
+
+#### Static
+
+- `Slice.EMPTY_BUF: Buffer` — Shared empty buffer singleton
+
+### `PoolAllocator`
+
+Pre-allocates a contiguous memory pool and manages slices using power-of-2 bucketing.
+
+#### `new PoolAllocator(poolTotal?: number)`
+
+Creates a pool allocator. Default pool size is 128 MB.
+
+#### Methods
+
+- `realloc(slice: Slice, byteLength: number): Slice` — Allocate, resize, or free a slice. Pass `0` to free.
+- `isFromPool(slice: Slice | null | undefined): boolean` — Check if a slice was allocated from this pool
+
+#### Properties
+
+- `size: number` — Total size of all active allocations
+- `stats: { size: number, padding: number, ratio: number, poolTotal: number, poolUsed: number, poolSize: number, poolCount: number }` — Detailed allocation statistics
+
+## License
+
+MIT

package.json

 {
   "name": "@nxtedition/slice",
-  "version": "1.0.4",
+  "version": "1.0.7",
   "type": "module",
@@ -8,5 +8,10 @@ "main": "lib/index.js",
   "files": [
-    "lib"
+    "lib",
+    "README.md",
+    "LICENSE"
   ],
-  "license": "UNLICENSED",
+  "license": "MIT",
+  "publishConfig": {
+    "access": "public"
+  },
   "scripts": {
@@ -16,4 +21,5 @@ "build": "rimraf lib && tsc && amaroc ./src/index.ts && mv src/index.js lib/",
     "typecheck": "tsc --noEmit",
-    "test": "node --test",
-    "test:ci": "node --test"
+    "test": "yarn build && node --test",
+    "test:ci": "yarn build && node --test",
+    "test:coverage": "node --test --experimental-test-coverage"
   },
@@ -26,3 +32,4 @@ "devDependencies": {
     "typescript": "^5.9.3"
-  }
+  },
+  "gitHead": "8dbd8386c6d4c511ffa81a904c58b6f648811a52"
 }

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