# ASCII

A utility library to perate on ASCII strings. 

## Interface

### <mark style="color:blue;">contains</mark>

**It checks if string a contains string b.**

```rust
public fun contains(a: String, b: String): bool
```

* **@param a:** A string.&#x20;
* **@param b**: Another string
* **@return bool.** True if `a` contains `b`.&#x20;

**Aborts**

* `b` is longer than `a`.

### <mark style="color:blue;">append</mark>

**Appends `a` and `b`**

```rust
public fun append(a: String, b: String): String
```

* **@param a:** The first subtring.&#x20;
* **@param b**: The second substring.&#x20;
* **@return String.**  `b` os longer than `a` \`a\` + \`b\` => "hello" \`append\` "world" => "helloworld".&#x20;

### <mark style="color:blue;">slice</mark>

**Returns a \[i, j) slice of the string starting at index i and going up to, but not including, index j.**

```rust
public fun append(a: String, b: String): String
```

* **@param s:** The string that will be sliced.&#x20;
* **@param i:** The first index of the substring. &#x20;
* **@param j:** The last index of the substring. This character is not included.&#x20;
* **@return String.** The substring.

  &#x20;

**Aborts**

* if `j` is greater than `s`.
* if `j` is smaller than `i`.

### <mark style="color:blue;">into\_char</mark>

**It returns the `Char` at index `i` from `string`.**

```rust
public fun into_char(string: &String, i: u64): Char
```

* **@param string:** The string that contains the `Char`.
* **@param i:** i The index of the `Char` we want to grab.
* **@return Char.** The `Char` at index `i`.

**Aborts**

* `i` is out of bounds

### <mark style="color:blue;">to\_lower\_case</mark>

**It lowercases the string.**

```rust
public fun to_lower_case(string: String): String
```

* **@param string:** The string we wish to lowercase.
* **@return String**. The lowercase `string`

### <mark style="color:blue;">to\_upper\_case</mark>

**It uppercases the string.**

```rust
public fun to_upper_case(string: String): String
```

* **@param string:** The string we wish to lowercase.
* **@return String**. The lowercase `string`

### <mark style="color:blue;">u128\_to\_string</mark>

**Converts a `u128` to its `ascii::String` decimal representation.**

```rust
public fun u128_to_string(value: u128): String
```

* **@param value:** A u128.
* **@return String.** The string representation of `value`. E.g. 128 => "128".

### <mark style="color:blue;">u128\_to\_hex\_string</mark>

**Converts a `u128` to its `ascii::String` hexadecimal representation.**

```rust
public fun u128_to_hex_string(value: u128): String 
```

* **@param value:** A u128.
* **@return String.** The HEX string representation of `value`. E.g. 10 => "0xA".

### <mark style="color:blue;">u128\_to\_hex\_string\_to\_fixed\_length</mark>

**Converts a `u128` to its `ascii::String` hexadecimal representation with fixed length (in whole bytes). The returned String is `2 * length + 2`(with '0x') in size.**

```rust
public fun u128_to_hex_string_fixed_length(value: u128, length: u128): String
```

* **@param value:** A u128.
* **@param length:** length of the string.
* **@return String.** The HEX string representation of `value`. E.g. 10 => "0xA".

### <mark style="color:blue;">bytes\_to\_hex\_string</mark>

**Converts a `vector<u8>` to its `ascii::String` hexadecimal representation.**

```rust
public fun bytes_to_hex_string(bytes: vector<u8>): String
```

* **@param** value A u128.
* **@return String.** The HEX string representation of `bytes`. E.g. 0b1010 => "0x0A".

### <mark style="color:blue;">addr\_into\_string</mark>

Converts an address `addr` to its `ascii::String` representation. Addresses are 32 bytes, whereas the string-encoded address is 64 bytes. Outputted strings do not include the 0x prefix.

```rust
public fun addr_into_string(addr: address): String
```

* **@param addr**: A 32-byte address.
* **@return** String. The `ascii::String` representation of `addr`.

### <mark style="color:blue;">u8\_to\_ascii</mark>

**Converts a u8 `num` to an ascii character.**

```rust
public fun u8_to_ascii(num: u8): u8
```

* **@param num:** decimal representation of an ASCII character.
* **@return u8.** The `ascii::String` code for `num`.

### <mark style="color:blue;">ascii\_to\_u8</mark>

**Converts an ASCII character to its decimal representation u8.**

```rust
public fun ascii_to_u8(char: u8): u8
```

* **@param char:** ASCII character.
* **@return u8.** The decimal representation of `char`.


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