Added a very complicated AsyncIterableReader class.

The class was already implemented in "https://deno.land/std@0.144.0/streams/conversion.ts". So, I litterally lost 1 day of work! I hate myself.
2023-06-12 12:02:15 -04:00
1 parent 17a1b4bed3
commit 0d627c9051
@@ -0,0 +1,271 @@
+// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+/**
+ * Provides helper functions to manipulate `Uint8Array` byte slices that are not
+ * included on the `Uint8Array` prototype.
+ *
+ * @module
+ */
+
+/** Returns the index of the first occurrence of the needle array in the source
+ * array, or -1 if it is not present.
+ *
+ * A start index can be specified as the third argument that begins the search
+ * at that given index. The start index defaults to the start of the array.
+ *
+ * The complexity of this function is O(source.lenth * needle.length).
+ *
+ * ```ts
+ * import { indexOfNeedle } from "./mod.ts";
+ * const source = new Uint8Array([0, 1, 2, 1, 2, 1, 2, 3]);
+ * const needle = new Uint8Array([1, 2]);
+ * console.log(indexOfNeedle(source, needle)); // 1
+ * console.log(indexOfNeedle(source, needle, 2)); // 3
+ * ```
+ */
+export function indexOfNeedle(
+  source: Uint8Array,
+  needle: Uint8Array,
+  start = 0,
+): number {
+  if (start >= source.length) {
+    return -1;
+  }
+  if (start < 0) {
+    start = Math.max(0, source.length + start);
+  }
+  const s = needle[0];
+  for (let i = start; i < source.length; i++) {
+    if (source[i] !== s) continue;
+    const pin = i;
+    let matched = 1;
+    let j = i;
+    while (matched < needle.length) {
+      j++;
+      if (source[j] !== needle[j - pin]) {
+        break;
+      }
+      matched++;
+    }
+    if (matched === needle.length) {
+      return pin;
+    }
+  }
+  return -1;
+}
+
+/** Returns the index of the last occurrence of the needle array in the source
+ * array, or -1 if it is not present.
+ *
+ * A start index can be specified as the third argument that begins the search
+ * at that given index. The start index defaults to the end of the array.
+ *
+ * The complexity of this function is O(source.lenth * needle.length).
+ *
+ * ```ts
+ * import { lastIndexOfNeedle } from "./mod.ts";
+ * const source = new Uint8Array([0, 1, 2, 1, 2, 1, 2, 3]);
+ * const needle = new Uint8Array([1, 2]);
+ * console.log(lastIndexOfNeedle(source, needle)); // 5
+ * console.log(lastIndexOfNeedle(source, needle, 4)); // 3
+ * ```
+ */
+export function lastIndexOfNeedle(
+  source: Uint8Array,
+  needle: Uint8Array,
+  start = source.length - 1,
+): number {
+  if (start < 0) {
+    return -1;
+  }
+  if (start >= source.length) {
+    start = source.length - 1;
+  }
+  const e = needle[needle.length - 1];
+  for (let i = start; i >= 0; i--) {
+    if (source[i] !== e) continue;
+    const pin = i;
+    let matched = 1;
+    let j = i;
+    while (matched < needle.length) {
+      j--;
+      if (source[j] !== needle[needle.length - 1 - (pin - j)]) {
+        break;
+      }
+      matched++;
+    }
+    if (matched === needle.length) {
+      return pin - needle.length + 1;
+    }
+  }
+  return -1;
+}
+
+/** Returns true if the prefix array appears at the start of the source array,
+ * false otherwise.
+ *
+ * The complexity of this function is O(prefix.length).
+ *
+ * ```ts
+ * import { startsWith } from "./mod.ts";
+ * const source = new Uint8Array([0, 1, 2, 1, 2, 1, 2, 3]);
+ * const prefix = new Uint8Array([0, 1, 2]);
+ * console.log(startsWith(source, prefix)); // true
+ * ```
+ */
+export function startsWith(source: Uint8Array, prefix: Uint8Array): boolean {
+  for (let i = 0, max = prefix.length; i < max; i++) {
+    if (source[i] !== prefix[i]) return false;
+  }
+  return true;
+}
+
+/** Returns true if the suffix array appears at the end of the source array,
+ * false otherwise.
+ *
+ * The complexity of this function is O(suffix.length).
+ *
+ * ```ts
+ * import { endsWith } from "./mod.ts";
+ * const source = new Uint8Array([0, 1, 2, 1, 2, 1, 2, 3]);
+ * const suffix = new Uint8Array([1, 2, 3]);
+ * console.log(endsWith(source, suffix)); // true
+ * ```
+ */
+export function endsWith(source: Uint8Array, suffix: Uint8Array): boolean {
+  for (
+    let srci = source.length - 1, sfxi = suffix.length - 1;
+    sfxi >= 0;
+    srci--, sfxi--
+  ) {
+    if (source[srci] !== suffix[sfxi]) return false;
+  }
+  return true;
+}
+
+/** Returns a new Uint8Array composed of `count` repetitions of the `source`
+ * array.
+ *
+ * If `count` is negative, a `RangeError` is thrown.
+ *
+ * ```ts
+ * import { repeat } from "./mod.ts";
+ * const source = new Uint8Array([0, 1, 2]);
+ * console.log(repeat(source, 3)); // [0, 1, 2, 0, 1, 2, 0, 1, 2]
+ * console.log(repeat(source, 0)); // []
+ * console.log(repeat(source, -1)); // RangeError
+ * ```
+ */
+export function repeat(source: Uint8Array, count: number): Uint8Array {
+  if (count === 0) {
+    return new Uint8Array();
+  }
+
+  if (count < 0) {
+    throw new RangeError("bytes: negative repeat count");
+  } else if ((source.length * count) / count !== source.length) {
+    throw new Error("bytes: repeat count causes overflow");
+  }
+
+  const int = Math.floor(count);
+
+  if (int !== count) {
+    throw new Error("bytes: repeat count must be an integer");
+  }
+
+  const nb = new Uint8Array(source.length * count);
+
+  let bp = copy(source, nb);
+
+  for (; bp < nb.length; bp *= 2) {
+    copy(nb.slice(0, bp), nb, bp);
+  }
+
+  return nb;
+}
+
+/** Concatenate the given arrays into a new Uint8Array.
+ *
+ * ```ts
+ * import { concat } from "./mod.ts";
+ * const a = new Uint8Array([0, 1, 2]);
+ * const b = new Uint8Array([3, 4, 5]);
+ * console.log(concat(a, b)); // [0, 1, 2, 3, 4, 5]
+ */
+export function concat(...buf: Uint8Array[]): Uint8Array {
+  let length = 0;
+  for (const b of buf) {
+    length += b.length;
+  }
+
+  const output = new Uint8Array(length);
+  let index = 0;
+  for (const b of buf) {
+    output.set(b, index);
+    index += b.length;
+  }
+
+  return output;
+}
+
+/** Returns true if the source array contains the needle array, false otherwise.
+ *
+ * A start index can be specified as the third argument that begins the search
+ * at that given index. The start index defaults to the beginning of the array.
+ *
+ * The complexity of this function is O(source.length * needle.length).
+ *
+ * ```ts
+ * import { includesNeedle } from "./mod.ts";
+ * const source = new Uint8Array([0, 1, 2, 1, 2, 1, 2, 3]);
+ * const needle = new Uint8Array([1, 2]);
+ * console.log(includesNeedle(source, needle)); // true
+ * console.log(includesNeedle(source, needle, 6)); // false
+ * ```
+ */
+export function includesNeedle(
+  source: Uint8Array,
+  needle: Uint8Array,
+  start = 0,
+): boolean {
+  return indexOfNeedle(source, needle, start) !== -1;
+}
+
+/** Copy bytes from the `src` array to the `dst` array. Returns the number of
+ * bytes copied.
+ *
+ * If the `src` array is larger than what the `dst` array can hold, only the
+ * amount of bytes that fit in the `dst` array are copied.
+ *
+ * An offset can be specified as the third argument that begins the copy at
+ * that given index in the `dst` array. The offset defaults to the beginning of
+ * the array.
+ *
+ * ```ts
+ * import { copy } from "./mod.ts";
+ * const src = new Uint8Array([9, 8, 7]);
+ * const dst = new Uint8Array([0, 1, 2, 3, 4, 5]);
+ * console.log(copy(src, dst)); // 3
+ * console.log(dst); // [9, 8, 7, 3, 4, 5]
+ * ```
+ *
+ * ```ts
+ * import { copy } from "./mod.ts";
+ * const src = new Uint8Array([1, 1, 1, 1]);
+ * const dst = new Uint8Array([0, 0, 0, 0]);
+ * console.log(copy(src, dst, 1)); // 3
+ * console.log(dst); // [0, 1, 1, 1]
+ * ```
+ */
+export function copy(src: Uint8Array, dst: Uint8Array, off = 0): number {
+  off = Math.max(0, Math.min(off, dst.byteLength));
+  const dstBytesAvailable = dst.byteLength - off;
+  if (src.byteLength > dstBytesAvailable) {
+    src = src.subarray(0, dstBytesAvailable);
+  }
+  dst.set(src, off);
+  return src.byteLength;
+}
+
+export { equals } from "./equals.ts";