Functions that convert ascii text strings of integers and floats/doubles to binary values computers use - by Simon Lightfoot - 22/01/2021

ascii_to_bin.dart

// MIT License
//
// Copyright (c) 2021 Simon Lightfoot
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//
import 'dart:typed_data';

void main() {
  final i = atoi('12345678');
  final v = atof('12345678.12345678');

  print(i);
  print(v);

  final b = Uint8List(8);
  final d = ByteData.view(b.buffer);
  d.setFloat64(0, v);
  print(b);
}

/// ascii to integer
int atoi(String value) {
  int result = 0;

  final s = value.codeUnits;
  int index = 0;

  int sign = 1;
  if(s[index] == 0x2B || s[index] == 0x2D){ // '+' or '-'
    if (s[index] == 0x2D){ // '-'
      sign = -1;
    }
    index++;
  }

  // while (character is > '0' and '9' )
  while (index < s.length && s[index] >= 0x30 && s[index] <= 0x39)
  {
    result = result * 10 + (s[index++] - 0x30); // '0'
  }

  return result * sign;
}

/// ascii to float
double atof(String value)
{
  double integer = 0, sign = 1, numerator = 0, denominator = 1;

  final s = value.codeUnits;
  int index = 0;

  if (s[index] == 0x2B || s[index] == 0x2D){ // '+' or '-'
    if (s[index] == 0x2D){ // '-'
      sign = -1;
    }
    index++;
  }

  // while (character is > '0' and '9' )
  while (index < s.length && s[index] >= 0x30 && s[index] <= 0x39){
    integer = integer * 10 + (s[index++] - 0x30); // '0'
  }

  if (index < s.length && s[index] == 0x2E){ // '.'
    index++; // skip the dot
    // while (character is > '0' and '9' )
    while (index < s.length && s[index] >= 0x30 && s[index] <= 0x39){
      numerator = numerator * 10 + (s[index++] - 0x30); // '0'
      denominator *= 10;
    }
  }

  return (integer + (numerator / denominator)) * sign;
}