denoland-deno/std/bytes/README.md

# bytes

bytes module is made to provide helpers to manipulation of bytes slice.

# usage

All the following functions are exposed in `mod.ts`.

## findIndex

Find first index of binary pattern from given binary array.

```typescript
import { findIndex } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

findIndex(
  new Uint8Array([1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 3]),
  new Uint8Array([0, 1, 2]),
);

// => returns 2
```

## findLastIndex

Find last index of binary pattern from given binary array.

```typescript
import { findLastIndex } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

findLastIndex(
  new Uint8Array([0, 1, 2, 0, 1, 2, 0, 1, 3]),
  new Uint8Array([0, 1, 2]),
);

// => returns 3
```

## equal

Check whether given binary arrays are equal to each other.

```typescript
import { equal } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

equal(new Uint8Array([0, 1, 2, 3]), new Uint8Array([0, 1, 2, 3])); // returns true
equal(new Uint8Array([0, 1, 2, 3]), new Uint8Array([0, 1, 2, 4])); // returns false
```

## hasPrefix

Check whether binary array has binary prefix.

```typescript
import { hasPrefix } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

hasPrefix(new Uint8Array([0, 1, 2]), new Uint8Array([0, 1])); // returns true
hasPrefix(new Uint8Array([0, 1, 2]), new Uint8Array([1, 2])); // returns false
```

## hasSuffix

Check whether binary array ends with suffix.

```typescript
import { hasSuffix } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

hasSuffix(new Uint8Array([0, 1, 2]), new Uint8Array([0, 1])); // returns false
hasSuffix(new Uint8Array([0, 1, 2]), new Uint8Array([1, 2])); // returns true
```

## repeat

Repeat bytes of given binary array and return new one.

```typescript
import { repeat } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

repeat(new Uint8Array([1]), 3); // returns Uint8Array(3) [ 1, 1, 1 ]
```

## concat

Concatenate two binary arrays and return new one.

```typescript
import { concat } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

concat(new Uint8Array([1, 2]), new Uint8Array([3, 4])); // returns Uint8Array(4) [ 1, 2, 3, 4 ]
```

## contains

Check source array contains pattern array.

```typescript
import { contains } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

contains(
  new Uint8Array([1, 2, 0, 1, 2, 0, 2, 1, 3]),
  new Uint8Array([0, 1, 2]),
); // => returns true

contains(
  new Uint8Array([1, 2, 0, 1, 2, 0, 2, 1, 3]),
  new Uint8Array([2, 2]),
); // => returns false
```

## copyBytes

Copy bytes from one binary array to another.

```typescript
import { copyBytes } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

const dst = new Uint8Array(4);
const src = Uint8Array.of(1, 2, 3, 4);
const len = copyBytes(src, dest); // returns len = 4
```