binarystream 2.6.10

use napi::bindgen_prelude::{BigInt, FromNapiValue};
use napi_derive::napi;
use napi::{ Result, Error, Status::GenericFailure };
use crate::binary::BinaryStream;
use crate::types::Uint8;

#[napi]
#[derive(Clone)]
/**

 * **VarLong**
 * 
 * Represents a 64 bit ( 8 bytes ) unsigned variable length integer. ( 0 to 18446744073709551615 )
*/
pub struct VarLong {}

#[napi]
impl VarLong {
  #[napi]
  /**

   * **read**
   * 
   * Reads a 64 bit ( 8 bytes ) unsigned variable length integer from the stream. ( 0 to 18446744073709551615 )
  */
  pub fn read(stream: &mut BinaryStream) -> Result<BigInt> {
    let mut num_read = 0;
    let mut result = 0;

    loop {
      let read = match Uint8::read(stream) {
        Ok(read) => read as u64,
        Err(err) => return Err(err)
      };

      let value = read & 0b01111111;
      result |= value << (7 * num_read);
      num_read += 1;
      if num_read > 10 {
        return Err(
          Error::new(
            GenericFailure,
            "VarLong is too big"
          )
        );
      }

      if (read & 0b10000000) == 0 {
        break;
      }
    }

    Ok(BigInt::from(result))
  }

  #[napi]
  /**

   * **write**
   * 
   * Writes a 64 bit ( 8 bytes ) unsigned variable length integer to the stream. ( 0 to 18446744073709551615 )
  */
  pub fn write(stream: &mut BinaryStream, value: BigInt) {
    let mut value = value.get_u64().1;
    loop {
      let mut byte = (value & 0b01111111) as u8;
      value >>= 7;
      if value != 0 {
        byte |= 0b10000000;
      }
      Uint8::write(stream, byte);
      if value == 0 {
        break;
      }
    }
  }
}


impl FromNapiValue for VarLong {
  unsafe fn from_napi_value(_: napi::sys::napi_env, _: napi::sys::napi_value) -> Result<Self> {
    Ok(VarLong {})
  }
}