feat: add $.hex codec

codecs/bench/hex.bench.ts

@@ -0,0 +1,36 @@
+import * as $ from "../../mod.ts"
+import { decodeHex, encodeHex } from "../../mod.ts"
+import { benchCodec } from "../../test-util.ts"
+
+const words = await Deno.readFile("words.txt")
+const cargoLock = await Deno.readFile("Cargo.lock")
+const cases = [
+  new Uint8Array(),
+  new Uint8Array(128),
+  words,
+  cargoLock,
+  new Uint8Array(Array(1000).fill([...words]).flat()),
+]
+
+Deno.bench(" ", () => {})
+
+for (const data of cases) {
+  const encoded = encodeHex(data)
+  decodeHex(encoded)
+  Deno.bench(`encode ${data.length} bytes`, () => {
+    encodeHex(data)
+  })
+  Deno.bench(`decode ${data.length} bytes`, () => {
+    decodeHex(encoded)
+  })
+}
+
+const $unsizedHex = $.hex($.uint8Array)
+for (const data of cases) {
+  benchCodec(`$unsizedHex ${data.length} bytes`, $unsizedHex, encodeHex(data))
+}
+
+for (const data of cases) {
+  const $sizedHex = $.hex($.sizedUint8Array(data.length))
+  benchCodec(`$sizedHex ${data.length} bytes`, $sizedHex, encodeHex(data))
+}

codecs/fixtures/hex.rs

@@ -0,0 +1,29 @@
+crate::fixtures!(
+  <Vec<u8>>::new(),
+  vec![0, 1, 2, 3, 4, 5u8],
+  vec![0xde, 0xad, 0xbe, 0xef_u8],
+  crate::CARGO_LOCK,
+  [0u8],
+  [1u8],
+  [255u8],
+  [
+    0xdd, 0x00, 0x00, 0xdd, 0x00, 0x00, 0xee, 0xee, 0xee, 0xee, 0x00, 0x00,
+    0x0c, 0xc0, 0x00, 0xcc_u8,
+  ],
+  [
+    0xdd, 0x00, 0x00, 0xdd, 0x00, 0x00, 0xee, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0xcc, 0xcc, 0x00_u8,
+  ],
+  [
+    0xdd, 0xdd, 0xdd, 0xdd, 0x00, 0x00, 0xee, 0xee, 0xee, 0xee, 0x00, 0x00,
+    0x00, 0x0c, 0xc0, 0x00_u8,
+  ],
+  [
+    0xdd, 0x00, 0x00, 0xdd, 0x00, 0x00, 0xee, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0xcc, 0xcc, 0x00_u8,
+  ],
+  [
+    0xdd, 0x00, 0x00, 0xdd, 0x00, 0x00, 0xee, 0xee, 0xee, 0xee, 0x00, 0x00,
+    0x0c, 0xc0, 0x00, 0xcc_u8,
+  ],
+);

codecs/hex.ts

@@ -0,0 +1,49 @@
+import { Codec, metadata, ScaleAssertError, withMetadata } from "../mod.ts"
+import { transform } from "./transform.ts"
+
+const encodeLookup = Array.from({ length: 256 }, (_, i) => i.toString(16).padStart(2, "0"))
+const decodeLookup = Array.from({ length: 128 }, (_, i) => parseInt(String.fromCharCode(i), 16) | 0)
+
+export function encodeHex(bytes: Uint8Array): string {
+  let str = ""
+  for (let i = 0; i < bytes.length; i++) {
+    str += encodeLookup[bytes[i]!]
+  }
+  return str
+}
+
+export function encodeHexPrefixed(bytes: Uint8Array) {
+  let str = "0x"
+  for (let i = 0; i < bytes.length; i++) {
+    str += encodeLookup[bytes[i]!]
+  }
+  return str
+}
+
+export function decodeHex(hex: string): Uint8Array {
+  if (hex.startsWith("0x")) hex = hex.slice(2)
+  if (hex.length % 2 === 1) hex = "0" + hex
+  const array = new Uint8Array(hex.length >> 1)
+  for (let i = 0; i < array.length; i++) {
+    array[i] = (decodeLookup[hex.charCodeAt(i << 1)!]! << 4) | decodeLookup[hex.charCodeAt(i << 1 | 1)!]!
+  }
+  return array
+}
+
+const hexRegex = /^(?:0x)?[\da-f]*$/i
+export function hex($inner: Codec<Uint8Array>): Codec<string> {
+  return withMetadata(
+    metadata("$.hex", hex, $inner),
+    transform({
+      $base: $inner,
+      encode: decodeHex,
+      decode: encodeHex,
+      assert(assert) {
+        assert.typeof(this, "string")
+        if (!hexRegex.test(assert.value as string)) {
+          throw new ScaleAssertError(this, assert.value, `${assert.path}: invalid hex`)
+        }
+      },
+    }),
+  )
+}

codecs/mod.ts

@@ -7,6 +7,7 @@ export * from "./compact.ts"
 export * from "./constant.ts"
 export * from "./deferred.ts"
 export * from "./float.ts"
+export * from "./hex.ts"
 export * from "./instance.ts"
 export * from "./int.ts"
 export * from "./iterable.ts"

codecs/test/hex.test.ts

@@ -0,0 +1,47 @@
+import * as $ from "../../mod.ts"
+import { testCodec, testInvalid } from "../../test-util.ts"
+import { encodeHex } from "../hex.ts"
+
+const $unsizedHex = $.hex($.uint8Array)
+
+testCodec($unsizedHex, [
+  "",
+  "000102030405",
+  "deadbeef",
+  encodeHex(await Deno.readFile("Cargo.lock")),
+])
+
+testCodec($.hex($.sizedUint8Array(1)), [
+  "00",
+  "01",
+  "ff",
+])
+
+testCodec($.hex($.sizedUint8Array(16)), [
+  "dd0000dd0000eeeeeeee00000cc000cc",
+  "dd0000dd0000ee000000000000cccc00",
+  "dddddddd0000eeeeeeee0000000cc000",
+  "dd0000dd0000ee000000000000cccc00",
+  "dd0000dd0000eeeeeeee00000cc000cc",
+])
+
+testInvalid($unsizedHex, [
+  null,
+  0x1234,
+  "0y00",
+  "hex",
+  "0x000000000000000000000.",
+  new Uint8Array([0, 1, 2, 3, 4]),
+])
+
+testInvalid($.hex($.sizedUint8Array(1)), [
+  null,
+  0x1234,
+  "0y00",
+  "hex",
+  "0x000000000000000000000.",
+  new Uint8Array([0, 1, 2, 3, 4]),
+  "0000",
+  "",
+  "-1",
+])

common/mod.ts

@@ -1,4 +1,4 @@
-// moderate --exclude *.test.ts
+// moderate
 
 export * from "./assert.ts"
 export * from "./buffer.ts"

fixtures.rs

@@ -18,6 +18,9 @@ pub mod deferred_fixtures;
 #[path = "./codecs/fixtures/float.rs"]
 pub mod float_fixtures;
 
+#[path = "./codecs/fixtures/hex.rs"]
+pub mod hex_fixtures;
+
 #[path = "./codecs/fixtures/int.rs"]
 pub mod int_fixtures;