pub fn parse_variable_byte_int<R: io::Read>(reader: &mut R) -> Result<Self, Error> {
    let mut multiplier: i32 = 1;
    let mut value: i32 = 0;

    loop {
      let mut b = [0; 1];
      reader.read_exact(&mut b)?;

      value += i32::from(b[0] & 127) * multiplier;

      if multiplier > (128 * 128 * 128) {
        return Err(Error::ParseError);
      }

      multiplier *= 128;

      if (b[0] & 128) == 0 {
        break;
      }
    }

    let parsed = match value {
      n if n <= 127 => Self::VariableByteInteger(VariableByte::One(u8::try_from(value)?)),
      n if n <= 16383 => Self::VariableByteInteger(VariableByte::Two(u16::try_from(value)?)),
      n if n <= 2_097_151 => Self::VariableByteInteger(VariableByte::Three(u32::try_from(value)?)),
      _ => Self::VariableByteInteger(VariableByte::Four(u32::try_from(value)?)),
    };

    Ok(parsed)
  }
/// Reads bytes from the reader and attempts to convert the bytes to DataType::VariableByteInteger (u8, 16, or u32).
///
/// [1.5.5 Variable Byte Integer](https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901011)
///
/// The Variable Byte Integer is encoded using an encoding scheme which uses a
/// single byte for values up to 127. Larger values are handled as follows. The
/// least significant seven bits of each byte encode the data, and the most
/// significant bit is used to indicate whether there are bytes following in
/// the representation. Thus, each byte encodes 128 values and a "continuation
/// bit". The maximum number of bytes in the Variable Byte Integer field is four.
/// The encoded value MUST use the minimum number of bytes necessary to represent
/// the value.
///
/// The algorithm for decoding a Variable Byte Integer type is as follows:
/// ```txt
/// multiplier = 1
/// value = 0
///
/// do
///    encodedByte = 'next byte from stream'
///    value += (encodedByte AND 127) * multiplier
///
///    if (multiplier > 128*128*128)
///       throw Error(Malformed Variable Byte Integer)
///    multiplier *= 128
/// while ((encodedByte AND 128) != 0)
/// ```
///
/// # Examples
///
/// ```rust
/// use mqtt_packet::{DataType, VariableByte};
/// use std::io;
///
/// let data: Vec<u8> = vec![0x80, 0x80, 0x80, 0x01];
/// let mut reader = io::BufReader::new(&data[..]);
/// let mut vari_type = DataType::parse_variable_byte_int(&mut reader).unwrap();
///
/// assert_eq!(
///   vari_type,
///   DataType::VariableByteInteger(VariableByte::Four(2097152))
/// );
/// ```
Reads bytes from the reader and attempts to convert the bytes to DataType::VariableByteInteger (u8, 16, or u32).

The Variable Byte Integer is encoded using an encoding scheme which uses a
single byte for values up to 127. Larger values are handled as follows. The
least significant seven bits of each byte encode the data, and the most
significant bit is used to indicate whether there are bytes following in
the representation. Thus, each byte encodes 128 values and a "continuation
bit". The maximum number of bytes in the Variable Byte Integer field is four.
The encoded value MUST use the minimum number of bytes necessary to represent
the value.

The algorithm for decoding a Variable Byte Integer type is as follows:
```txt
multiplier = 1
value = 0

do
encodedByte = 'next byte from stream'
value += (encodedByte AND 127) * multiplier

if (multiplier > 128*128*128)
throw Error(Malformed Variable Byte Integer)
multiplier *= 128
while ((encodedByte AND 128) != 0)
```
Reads bytes from the reader and attempts to convert the bytes to DataType :: VariableByteInteger ( u8 16 or u32 ) . The Variable Byte Integer is encoded using an encoding scheme which uses a single byte for values up to 127 . Larger values are handled as follows . The least significant seven bits of each byte encode the data and the most significant bit is used to indicate whether there are bytes following in the representation . Thus each byte encodes 128 values and a " continuation bit " . The maximum number of bytes in the Variable Byte Integer field is four . The encoded value MUST use the minimum number of bytes necessary to represent the value . The algorithm for decoding a Variable Byte Integer type is as follows : ` ` ` txt multiplier = 1 value = 0 do encodedByte = ' next byte from stream ' value + = ( encodedByte AND 127 ) * multiplier if ( multiplier > 128 * 128 * 128 ) throw Error ( Malformed Variable Byte Integer ) multiplier * = 128 while (( encodedByte AND 128 ) ! = 0 ) ` ` `
pub fn parse_variable_byte_int<R: io::Read>(reader: &mut R) -> Result<Self, Error> {
    let mut multiplier: i32 = 1;
    let mut value: i32 = 0;
    loop {
      let mut b = [0; 1];
      reader.read_exact(&mut b)?;
      value += i32::from(b[0] & 127) * multiplier;
      if multiplier > (128 * 128 * 128) {
        return Err(Error::ParseError);
      }
      multiplier *= 128;
      if (b[0] & 128) == 0 {
        break;
      }
    }
    let parsed = match value {
      n if n <= 127 => Self::VariableByteInteger(VariableByte::One(u8::try_from(value)?)),
      n if n <= 16383 => Self::VariableByteInteger(VariableByte::Two(u16::try_from(value)?)),
      n if n <= 2_097_151 => Self::VariableByteInteger(VariableByte::Three(u32::try_from(value)?)),
      _ => Self::VariableByteInteger(VariableByte::Four(u32::try_from(value)?)),
    };
    Ok(parsed)
  }
pub fn parse_variable_byte_int < R : io :: Read > ( reader : & mut R ) -> Result < Self , Error > { let mut multiplier : i32 = 1 ; let mut value : i32 = 0 ; loop { let mut b = [ 0 ; 1 ] ; reader . read_exact ( & mut b ) ? ; value += i32 :: from ( b [ 0 ] & 127 ) * multiplier ; if multiplier > ( 128 * 128 * 128 ) { return Err ( Error :: ParseError ) ; } multiplier *= 128 ; if ( b [ 0 ] & 128 ) == 0 { break ; } } let parsed = match value { n if n <= 127 => Self :: VariableByteInteger ( VariableByte :: One ( u8 :: try_from ( value ) ? ) ) , n if n <= 16383 => Self :: VariableByteInteger ( VariableByte :: Two ( u16 :: try_from ( value ) ? ) ) , n if n <= 2_097_151 => Self :: VariableByteInteger ( VariableByte :: Three ( u32 :: try_from ( value ) ? ) ) , _ => Self :: VariableByteInteger ( VariableByte :: Four ( u32 :: try_from ( value ) ? ) ) , } ; Ok ( parsed ) }
Reads bytes from the reader and attempts to convert the bytes to DataType::VariableByteInteger (u8, 16, or u32).
Reads bytes from the reader and attempts to convert the bytes to DataType :: VariableByteInteger ( u8 16 or u32 ) .
reader
&mut R
reader
&mut R
examples
```rust
use mqtt_packet::{DataType, VariableByte};
use std::io.

let data: Vec = vec![0x80, 0x80, 0x80, 0x01];
let mut reader = io::BufReader::new(&data[..]);
let mut vari_type = DataType::parse_variable_byte_int(&mut reader).unwrap().

assert_eq!(
vari_type,
DataType::VariableByteInteger(VariableByte::Four(2097152))
);
```
` ` ` rust use mqtt_packet :: { DataType VariableByte } ; use std :: io . let data : Vec = vec! [ 0x80 0x80 0x80 0x01 ] ; let mut reader = io :: BufReader :: new ( &data [ .. ] ) ; let mut vari_type = DataType :: parse_variable_byte_int ( &mut reader ) . unwrap () . assert_eq! ( vari_type DataType :: VariableByteInteger ( VariableByte :: Four ( 2097152 )) ) ; ` ` `