Add CBigInt skeleton

1 files changed, 98 insertions, 0 deletions

diff --git a/src/crypt/cbigint.h b/src/crypt/cbigint.h
new file mode 100644
index 0000000..f4ea407
--- /dev/null
+++ b/src/crypt/cbigint.h
@@ -0,0 +1,98 @@
+#ifndef CBIGINT_H
+#define CBIGINT_H
+
+/**
+ * An integer number with unlimited number of digits. Low digit is at low address.
+ *
+ * @author Walter Roth
+ */
+
+//define the base type of the number here. Useable types are: char, short int
+typedef char BaseType;
+struct BaseStruct
+{
+    BaseType low;
+    BaseType high;
+};
+
+union LongBaseType
+{
+    short int allSegments;
+    BaseStruct Segment;
+};
+
+class CBigInt
+{
+public:
+    /**
+     * Default constructor. Creates a number with size zero digits.
+     * Converts value to it's CbigInt representation.
+     */
+    CBigInt(int value = 0);
+
+    /**
+     * Copy constructor. Creates a deep copy.
+     */
+    CBigInt(const CBigInt & toCopy);
+
+    /**
+     * Destructor frees memory.
+     */
+    ~CBigInt();
+
+    /**
+     * Sets the new size, allocates memory and initializes with 0.
+     * If newSize is smaller than old,* _Size is reduced as long as
+     * digits to delete are zero. Returns final size.
+     */
+    int setSize(int newSize);
+
+    /**
+     * Returns the number of digits available (_Size)
+     */
+    int size() const;
+
+    /**
+     * Sets digit at position to value
+     */
+    void setDigit(int pos, BaseType value);
+
+    /**
+     * Operator +
+     */
+    CBigInt operator +(const CBigInt & n2);
+
+    /**
+     * Returns the number as a hexadecimal string
+     */
+    const char * toHexString()const;
+
+    /**
+     * Returns true, if LongBaseType is twice the size of BaseType
+     */
+    static bool isLongOk();
+
+private:
+    /**
+     * Make a deep copy
+     */
+    void copy(const CBigInt & toCopy);
+
+private:
+    /**
+     * The start of the digit-array. Points to LSB.
+     */
+    BaseType * _Digits;
+
+    /**
+     * The number of Digits allocated.
+     */
+    int _Size;
+
+    /**
+     * The string buffer for toXXString functions
+     */
+    static char * _StringBuffer;
+}
+
+#endif // CBIGINT_H