From 156d2701854f7a7ea74fb857fce26e23fcc41353 Mon Sep 17 00:00:00 2001
From: EmaMaker <emamaker0@gmail.com>
Date: Sun, 3 Jul 2022 16:55:09 +0200
Subject: [PATCH] rewrite of base converter

---
 base_converter.py | 170 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 170 insertions(+)
 create mode 100644 base_converter.py

diff --git a/base_converter.py b/base_converter.py
new file mode 100644
index 0000000..4031db6
--- /dev/null
+++ b/base_converter.py
@@ -0,0 +1,170 @@
+def decimalToBase(num, base):
+    negative = num < 0
+
+    if negative:
+        num *= -1
+
+    if base == "BCD":
+        result = ""
+
+        while num != 0:
+            digit = int(num) % 10
+            digit_conv = decimalToBase(digit, 2)
+            result = "0"*(4-len(digit_conv)) + digit_conv + result
+
+            num = (int) (num / 10)
+    
+    elif base == "2CP":
+        part_result = decimalToBase(num, 2)
+
+        if negative:
+            result = "1"
+            one = False
+            for i in range(1, len(part_result)):
+                if not(one) and part_result[i] == "1":
+                    one = True
+
+                if one and negative:
+                    result += str( 1 - int(part_result[i]))
+                else:
+                    result += part_result[i]
+        else:
+            result = "0" + part_result
+
+    else:
+        base = int(base)
+        num = int(num)
+        lResult = []
+
+        while num != 0:
+            lResult.insert(0, num % base)
+            num = int(num / base)
+            
+        #if an index of the list is >= 10 is replaced by an upper letter in ASCII (10-->A, 11-->B). Useful for bases > 10
+        for i in range(0, len(lResult)):
+            if lResult[i] >= 10:
+                lResult[i] = chr(lResult[i] + 55)
+
+        result = ''.join(str(e) for e in lResult)
+
+    if negative and base != "2CP":
+        return "-" + result
+    else:
+        return result
+
+
+def baseToDecimal(num, base):
+    if num == "":
+        return 0
+
+    negative = num[0] == '-'
+    if negative:
+        num = num[1:]
+
+    if base == "BCD":
+        s = ""
+        exp = 0
+        count = 0
+        result = 0
+
+        for i in range(len(num)-1, -1, -1):
+            count += 1
+            s += num[i]
+
+            if count == 4:
+                part_result = baseToDecimal(s[::-1], 2)
+
+                if part_result > 9:
+                    raise ValueError(f'Number > 9 ({s[::-1]} => {part_result}) present in BCD')
+                else:
+                    result += part_result * (10**exp)
+                    exp += 1
+                    count = 0
+                    s = ""
+
+        part_result = baseToDecimal(s[::-1], 2)
+        if part_result > 9:
+            raise ValueError(f'Number > 9 ({s[::-1]} => {part_result}) present in BCD')
+        else:
+            result += part_result * (10**exp)
+
+    else:
+        if base == "2CP":
+            calc_base = 2
+            if negative:
+                raise ValueError(f"2CP can't have negative sign")
+
+        else:
+            calc_base = int(base)
+
+        result = 0
+        lnum = len(num)
+
+        for i in range(0, lnum):
+            exp = calc_base**(lnum-1-i)
+            if("0" <= num[i] <= "9"):
+                
+                if int(num[i]) >= calc_base:
+                    raise ValueError(f'Digit {num[i]} is >= than base {calc_base}')
+
+                if base == "2CP" and i == 0:
+                    #MSB needs to be subtracted in cp2
+                    result -= int(num[i]) * exp
+                else :
+                    result += int(num[i]) * exp
+            
+            else:
+
+                if (ord(num[i]) - 55) >= calc_base:
+                    raise ValueError(f'Digit {num[i]} ({ord(num[i]) - 55}) is >= than base {calc_base}')
+
+                #allow for bases > 10 where letters are required
+                result += (ord(num[i]) - 55) * exp
+
+    if negative:
+        return -result
+    else:
+        return result
+
+if __name__ == "__main__":
+    number = input("Type in the number: ")
+    base1 = input("Type the starting numerical base: ")
+    base2 = input("Type the numerical base you want to convert it to: ")
+
+    num1 = int(baseToDecimal(number, base1))
+
+    print(num1)
+
+    num_final = decimalToBase(num1, base2)
+
+    print(f'{number} ({base1}) = {num_final}({base2})')
+
+
+
+    # try:
+    #     print(baseToDecimal("11111111", 2))
+    #     print(baseToDecimal("31", 8))
+    #     print(baseToDecimal("FF", 16))
+    #     print(baseToDecimal("100", "2CP"))
+    #     print(baseToDecimal("", 2))
+    #     print(baseToDecimal("0110", "BCD"))
+    #     print(baseToDecimal("110110", "BCD"))
+    #     print()
+    #     print(baseToDecimal("-11111111", 2))
+    #     print(baseToDecimal("-31", 8))
+    #     print(baseToDecimal("-FF", 16))
+    #     print(baseToDecimal("", 2))
+    #     print(baseToDecimal("-0110", "BCD"))
+    #     print(baseToDecimal("-110110", "BCD"))
+    #     # print(baseToDecimal("-100", "2CP"))
+    #     # print(baseToDecimal("110111", "BCD"))
+    #     print()
+    #     print(decimalToBase(127, "2CP"))
+    #     print(decimalToBase(-4, "2CP"))
+    #     print(decimalToBase(169, "BCD"))        
+    #     print(decimalToBase(255, 2))
+    #     print(decimalToBase(128, 2))
+    #     print(decimalToBase(127, 2))
+
+    # except ValueError as v:
+    #     print(v)
\ No newline at end of file