Conversions from bases 0-16, 2CP, BCD

lib/calculations.dart

@@ -0,0 +1,144 @@
+import 'dart:math';
+
+String decimalToBase(int number, toBase) {
+  //current base as integer
+  String tmpBase = toBase.toUpperCase();
+  if (tmpBase == "HEX") tmpBase = "16";
+
+  bool negative = number < 0;
+  if (negative) number *= -1;
+
+  String res = "";
+  switch (tmpBase) {
+    case "BCD":
+      String n = number.toString();
+      for (int i = 0; i < n.length; i++) {
+        String digit = decimalToBase(int.parse(n[i]), "2");
+        int missingZeros = 4 - digit.length;
+        for (int i = 0; i < missingZeros; i++) {
+          digit = "0" + digit;
+        }
+        res += digit;
+      }
+      if (negative) res = "-" + res;
+      break;
+    case "2CP":
+      String binary = decimalToBase(number, 2);
+      bool gotOne = false;
+      if (negative) {
+        for (int i = 0; i < binary.length; i++) {
+          if (gotOne) {
+            if (binary[i] == "1")
+              binary[i] == "0";
+            else
+              binary[i] == "1";
+          } else {
+            if (binary[i] == "1") gotOne = true;
+          }
+        }
+        res = binary;
+      } else {
+        res = "0" + binary;
+      }
+      break;
+    default:
+      int base = int.parse(tmpBase); //current base as integer
+      List<int> digits = [];
+
+      while (number != 0) {
+        digits.add(number % base);
+        number = number ~/ base;
+      }
+      digits = digits.reversed.toList();
+
+      for (int i = 0; i < digits.length; i++) {
+        if (digits[i] >= 10) {
+          res += String.fromCharCode(digits[i] + 55);
+        } else {
+          res += digits[i].toString();
+        }
+      }
+      if (negative) res = "-" + res;
+      break;
+  }
+  return res;
+}
+
+String baseToDecimal(String number, String pBase) {
+  bool negative = number.startsWith('-');
+  if (negative) number = number.split('-')[1];
+
+  //current base as integer
+  String tmpBase = pBase.toUpperCase();
+  if (tmpBase == "HEX") tmpBase = "16";
+
+  String cBase = tmpBase;
+  if (cBase == "BCD" || cBase == "2CP") cBase = "2";
+  int controlBase = int.parse(cBase);
+
+  for (int i = 0; i < number.length; i++) {
+    if (charToDigit(number, i) >= controlBase) {
+      return "error-invalid-number-for-base";
+    }
+  }
+
+  String res = "";
+  switch (tmpBase) {
+    case "BCD":
+      int missingZeros = (4 - number.length % 4) % 4;
+      for (int i = 0; i < missingZeros; i++) number = "0" + number;
+
+      for (int i = 0; i < number.length; i += 4) {
+        String n = number[i];
+        n += number[i + 1];
+        n += number[i + 2];
+        n += number[i + 3];
+        String n1 = baseToDecimal(n, "2");
+        print(n1);
+        if (int.parse(n1) > 9) return "error-bcd-greater-nine";
+        res += n1;
+      }
+      break;
+    case "2CP":
+      if (negative) {
+        return "error-negative-cp2";
+      }
+
+      int dres = 0;
+      number = number.split('').reversed.join('').toString();
+      for (int i = 0; i < number.length; i++) {
+        int add = int.parse(number[i]) * pow(2, i).toInt();
+        if (i == number.length - 1) add *= -1;
+        dres += add;
+      }
+      res = dres.toString();
+      break;
+    default:
+      int base = int.parse(tmpBase);
+      List<int> digits = [];
+
+      // Get the value in decimal of the current digit
+      for (int i = 0; i < number.length; i++) {
+        int digit = charToDigit(number, i);
+        digits.add(digit);
+      }
+
+      //Reverse the list
+      digits = digits.reversed.toList();
+
+      int dres = 0;
+      for (int i = 0; i < digits.length; i++) {
+        dres += digits[i] * pow(base, i).toInt();
+      }
+      res = dres.toString();
+      break;
+  }
+  return res;
+}
+
+int charToDigit(String s, int i) {
+  return isDigit(s, i) ? int.parse(s[i]) : s.codeUnitAt(i) - 55;
+}
+
+// https://stackoverflow.com/questions/25872456/dart-what-is-the-fastest-way-to-check-if-a-particular-symbol-in-a-string-is-a-d
+bool isDigit(String s, int i) => (s.codeUnitAt(i) ^ 0x30) <= 9;

lib/main.dart

@@ -1,4 +1,7 @@
+import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter/widgets.dart';
+import 'package:base_converter/calculations.dart';
 
 void main() {
   runApp(const MyApp());
@@ -13,15 +16,6 @@ class MyApp extends StatelessWidget {
     return MaterialApp(
       title: 'Base Converter',
       theme: ThemeData(
-        // This is the theme of your application.
-        //
-        // Try running your application with "flutter run". You'll see the
-        // application has a blue toolbar. Then, without quitting the app, try
-        // changing the primarySwatch below to Colors.green and then invoke
-        // "hot reload" (press "r" in the console where you ran "flutter run",
-        // or simply save your changes to "hot reload" in a Flutter IDE).
-        // Notice that the counter didn't reset back to zero; the application
-        // is not restarted.
         primarySwatch: Colors.blue,
       ),
       home: const MyHomePage(),
@@ -37,9 +31,8 @@ class MyHomePage extends StatefulWidget {
 }
 
 class _MyHomePageState extends State<MyHomePage> {
-  String fromBase = "One";
+  String fromBase = "2", savedFromBase = "";
-  String toBase = "One";
+  String toBase = "10", savedToBase = "";
-
   String result = "";
 
   late TextEditingController _controller;
@@ -53,7 +46,9 @@ class _MyHomePageState extends State<MyHomePage> {
 
   @override
   Widget build(BuildContext context) {
-    return Scaffold(
+    return GestureDetector(
+      onTap: () => hidekbd,
+      child: Scaffold(
         appBar: AppBar(
           title: const Text("Base Converter"),
           actions: [
@@ -83,13 +78,14 @@ class _MyHomePageState extends State<MyHomePage> {
                 icon: const Icon(Icons.info_outline_rounded))
           ],
         ),
-      body: SafeArea(
+        body: Container(
-        child: Container(
           margin: const EdgeInsets.fromLTRB(24, 32, 24, 32),
           child: Column(children: [
             mainBody(),
             Expanded(
-              child: Center(child: richText),
+              child: Container(
+                  margin: const EdgeInsets.all(24),
+                  child: Center(child: resultToRichText())),
             )
           ]),
         ),
@@ -110,11 +106,11 @@ class _MyHomePageState extends State<MyHomePage> {
             TextField(
               controller: _controller,
               decoration: const InputDecoration(hintText: "Number "),
+              keyboardType: TextInputType.phone,
             ),
-            Row(mainAxisAlignment: MainAxisAlignment.spaceBetween, children: [
+            Row(
-              baseSelector("From:", fromBase),
+                mainAxisAlignment: MainAxisAlignment.spaceBetween,
-              baseSelector("To:", toBase)
+                children: [baseSelector("From:", 0), baseSelector("To:", 1)]),
-            ]),
             Row(children: [
               Expanded(
                   child: TextButton(
@@ -131,13 +127,74 @@ class _MyHomePageState extends State<MyHomePage> {
     );
   }
 
-  void calculate() {}
+  void hidekbd() {
+    FocusManager.instance.primaryFocus?.unfocus();
+  }
 
-  void decimalToBase() {}
+  RichText resultToRichText() {
+    switch (result) {
+      case "error-negative-in-cp2":
+        return errorString("Error: 2CP number can't have a negative sign");
+      case "error-bcd-greater-nine":
+        return errorString("Error: BCD can only code digits from 0 to 9");
+      case "error-invalid-number-for-base":
+        return errorString(
+            "Error: a digit is greater than or equal to the base");
+      case "":
+        return RichText(
+          text: TextSpan(
+            text: '',
+            style: DefaultTextStyle.of(context).style,
+            children: const <TextSpan>[],
+          ),
+        );
+      default:
+        return RichText(
+          text: TextSpan(
+            text: '',
+            style: DefaultTextStyle.of(context).style,
+            children: <TextSpan>[
+              mainNumber(_controller.text),
+              baseSubtitle("($savedFromBase)"),
+              mainNumber(" = $result"),
+              baseSubtitle("($savedToBase)"),
+            ],
+          ),
+        );
+    }
+  }
 
-  void baseToDecimal() {}
+  RichText errorString(String content) {
+    return RichText(
+      text: TextSpan(
+        text: '',
+        style: DefaultTextStyle.of(context).style,
+        children: <TextSpan>[
+          TextSpan(
+              text: content,
+              style: const TextStyle(
+                  color: Colors.black,
+                  fontSize: 12,
+                  fontWeight: FontWeight.normal,
+                  fontFamily: "Roboto")),
+        ],
+      ),
+    );
+  }
 
-  Container baseSelector(String labelText, String value) {
+  TextSpan mainNumber(String text) {
+    return TextSpan(
+        text: text,
+        style: const TextStyle(
+            color: Colors.black, fontSize: 18, fontWeight: FontWeight.bold));
+  }
+
+  TextSpan baseSubtitle(String text) {
+    return TextSpan(
+        text: text, style: const TextStyle(color: Colors.black, fontSize: 14));
+  }
+
+  Container baseSelector(String labelText, int i) {
     return Container(
       margin: const EdgeInsets.all(4),
       child: Row(
@@ -147,17 +204,10 @@ class _MyHomePageState extends State<MyHomePage> {
           const SizedBox(
             width: 10,
           ),
-          dpb(value),
+          DropdownButton<String>(
-        ],
+            value: i == 0 ? fromBase : toBase,
-      ),
-    );
-  }
-
-  DropdownButton dpb(String dropdownValue) {
-    return DropdownButton<String>(
-      value: dropdownValue,
             icon: const Icon(Icons.arrow_downward),
-      iconSize: 24,
+            iconSize: 16,
             elevation: 16,
             style: const TextStyle(color: Colors.deepPurple),
             underline: Container(
@@ -166,34 +216,55 @@ class _MyHomePageState extends State<MyHomePage> {
             ),
             onChanged: (String? newValue) {
               setState(() {
-          dropdownValue = newValue!;
+                if (i == 0) {
+                  fromBase = newValue!;
+                } else if (i == 1) {
+                  toBase = newValue!;
+                }
               });
             },
-      items: <String>[
+            items: items.map<DropdownMenuItem<String>>((String value) {
-        'One',
-        'Two',
-        'Three',
-        'Four',
-        'Five',
-        'Six',
-        'Seven',
-        'Eight',
-        'Nine',
-        'Ten',
-        'Eleven',
-        'Twelve',
-        'Thirteen',
-        'Fourteen',
-        'Fifteen',
-        'Hex',
-        'BCD',
-        '2\'s CP'
-      ].map<DropdownMenuItem<String>>((String value) {
               return DropdownMenuItem<String>(
                 value: value,
                 child: Text(value),
               );
             }).toList(),
+          ),
+        ],
+      ),
     );
   }
+
+  List<String> items = <String>[
+    '1',
+    '2',
+    '3',
+    '4',
+    '5',
+    '6',
+    '7',
+    '8',
+    '9',
+    '10',
+    '11',
+    '12',
+    '13',
+    '14',
+    '15',
+    'Hex',
+    'BCD',
+    "2CP"
+  ];
+
+  void calculate() {
+    setState(() {
+      hidekbd();
+      savedFromBase = fromBase;
+      savedToBase = toBase;
+
+      String s = baseToDecimal(_controller.text.toUpperCase(), savedFromBase);
+      if (!s.startsWith("error")) s = decimalToBase(int.parse(s), savedToBase);
+      result = s;
+    });
+  }
 }