Diff: ttmathdec.h

Revision:

0:04a9f72bbca7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ttmathdec.h	Tue Jul 30 18:43:48 2013 +0000
@@ -0,0 +1,420 @@
+/*
+ * This file is a part of TTMath Bignum Library
+ * and is distributed under the (new) BSD licence.
+ * Author: Tomasz Sowa <t.sowa@ttmath.org>
+ */
+
+/* 
+ * Copyright (c) 2012, Tomasz Sowa
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *    
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *    
+ *  * Neither the name Tomasz Sowa nor the names of contributors to this
+ *    project may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef headerfilettmathdec
+#define headerfilettmathdec
+
+#include "ttmathtypes.h"
+#include "ttmaththreads.h"
+#include "ttmathuint.h"
+
+
+
+namespace ttmath
+{
+
+template<uint value_size, uint dec_digits>
+class Dec
+{
+public:
+
+    UInt<value_size> value;
+    unsigned char info;
+
+
+    /*!
+        Sign
+        the mask of a bit from 'info' which means that there is a sign
+        (when the bit is set)
+    */
+    #define TTMATH_DEC_SIGN 128
+
+
+    /*!
+        Not a number
+        if this bit is set that there is not a valid number
+    */
+    #define TTMATH_DEC_NAN  64
+
+
+
+
+    Dec()
+    {
+        info = TTMATH_DEC_NAN;
+    }
+
+
+    Dec(const char * s)
+    {
+        info = TTMATH_DEC_NAN;
+        FromString(s);
+    }
+
+
+    Dec<value_size, dec_digits> & operator=(const char * s)
+    {
+        FromString(s);
+
+    return *this;
+    }
+
+
+    uint FromString(const char * s, const char ** after_source = 0, bool * value_read = 0)
+    {
+        return FromStringBase(s, after_source, value_read);
+    }
+
+
+    void ToString(std::string & result) const
+    {
+        ToStringBase(result);
+    }
+
+
+    /*!
+        this method clears a specific bit in the 'info' variable
+
+        bit is one of: 
+    */
+    void ClearInfoBit(unsigned char bit)
+    {
+        info = info & (~bit);
+    }
+
+
+    /*!
+        this method sets a specific bit in the 'info' variable
+
+        bit is one of: 
+
+    */
+    void SetInfoBit(unsigned char bit)
+    {
+        info = info | bit;
+    }
+
+
+    /*!
+        this method returns true if a specific bit in the 'info' variable is set
+
+        bit is one of: 
+    */
+    bool IsInfoBit(unsigned char bit) const
+    {
+        return (info & bit) != 0;
+    }
+
+
+    bool IsNan() const 
+    {
+        return IsInfoBit(TTMATH_DEC_NAN);
+    }
+
+
+    bool IsSign() const 
+    {
+        return IsInfoBit(TTMATH_DEC_SIGN);
+    }
+
+
+    /*!
+        this method sets the sign
+
+            e.g.
+            -1 -> -1
+            2  -> -2
+
+        we do not check whether there is a zero or not, if you're using this method
+        you must be sure that the value is (or will be afterwards) different from zero
+    */
+    void SetSign()
+    {
+        SetInfoBit(TTMATH_DEC_SIGN);
+    }
+
+
+    void SetNaN()
+    {
+        SetInfoBit(TTMATH_DEC_NAN);
+    }
+
+
+    void Abs()
+    {
+        ClearInfoBit(TTMATH_DEC_SIGN);
+    }
+
+
+
+    uint Add(const Dec<value_size, dec_digits> & arg)
+    {
+    uint c = 0;
+
+        if( IsSign() == arg.IsSign() )
+        {
+            c += value.Add(arg.value);        
+        }
+        else
+        {
+            bool is_sign;
+
+            if( value > arg.value )
+            {
+                is_sign = IsSign();
+                value.Sub(arg.value);
+            }
+            else
+            {
+                is_sign = arg.IsSign();
+                UInt<value_size> temp(this->value);
+                value = arg.value;
+                value.Sub(temp);
+            }
+
+            is_sign ? SetSign() : Abs();
+        }
+
+        if( c )
+            SetNaN();
+
+    return (c==0)? 0 : 1;
+    }
+
+/*
+    uint Sub(const Dec<value_size, dec_digits> & arg)
+    {
+    }
+*/
+
+private:
+
+
+
+
+
+
+#ifndef TTMATH_MULTITHREADS
+
+    /*!
+    */
+    void SetMultipler(UInt<value_size> & result)
+    {
+        // this guardian is initialized before the program runs (static POD type)
+        static int guardian = 0;
+        static UInt<value_size> multipler;
+    
+        if( guardian == 0 )
+        {
+            multipler = 10;
+            multipler.Pow(dec_digits);
+            guardian = 1;
+        }
+
+        result = multipler;
+    }
+
+#else
+
+    /*!
+    */
+    void SetMultipler(UInt<value_size> & result)
+    {
+        // this guardian is initialized before the program runs (static POD type)
+        volatile static sig_atomic_t guardian = 0;
+        static UInt<value_size> * pmultipler;
+    
+        // double-checked locking
+        if( guardian == 0 )
+        {
+            ThreadLock thread_lock;
+
+            // locking
+            if( thread_lock.Lock() )
+            {
+                static UInt<value_size> multipler;
+
+                if( guardian == 0 )
+                {
+                    pmultipler = &multipler;
+                    multipler = 10;
+                    multipler.Pow(dec_digits);
+                    guardian = 1;
+                }
+            }
+            else
+            {
+                // there was a problem with locking, we store the result directly in 'result' object
+                result = 10;
+                result.Pow(dec_digits);
+                
+            return;
+            }
+
+            // automatically unlocking
+        }
+
+        result = *pmultipler;
+    }
+
+#endif
+
+
+
+    /*!
+        an auxiliary method for converting from a string
+    */
+    template<class char_type>
+    uint FromStringBase(const char_type * s, const char_type ** after_source = 0, bool * value_read = 0)
+    {
+        UInt<value_size> multipler;
+        const char_type * after;
+        uint c = 0;
+        info = 0;
+
+        Misc::SkipWhiteCharacters(s);
+
+        if( *s == '-' )
+        {
+            s += 1;
+            SetSign();
+        }
+        else
+        if( *s == '+' )
+        {
+            s += 1;
+        }
+
+        c += value.FromString(s, 10, &after, value_read);
+
+        if( after_source )
+            *after_source = after;
+
+        SetMultipler(multipler);
+        c += value.Mul(multipler);
+
+        if( *after == '.' )
+            c += FromStringBaseAfterComma(after+1, after_source);
+
+        if( c )
+            SetInfoBit(TTMATH_DEC_NAN);
+
+    return (c==0)? 0 : 1;
+    }
+
+
+    template<class char_type>
+    uint FromStringBaseAfterComma(const char_type * s, const char_type ** after_source = 0, bool * value_read = 0)
+    {
+        UInt<value_size> temp;
+        UInt<value_size> multipler;
+        sint z;
+        uint c = 0;
+        size_t i = dec_digits;
+
+        SetMultipler(multipler);
+
+        for( ; i>0 && (z=Misc::CharToDigit(*s, 10)) != -1 ; --i, ++s )
+        {
+            multipler.DivInt(10);
+            temp.SetZero();
+
+            if( value_read )
+                *value_read = true;
+
+            if( c == 0 )
+            {
+                temp.table[0] = z;
+                c += temp.Mul(multipler);
+                c += value.Add(temp);
+            }
+        }
+
+        if( i == 0 && (z=Misc::CharToDigit(*s, 10)) != -1 && z >= 5 )
+            c += value.AddOne();
+
+        if( after_source )
+        {
+            while( (z=Misc::CharToDigit(*s, 10)) != -1 )
+                s += 1;
+
+            *after_source = s;
+        }
+
+    return c;
+    }
+
+
+
+    template<class string_type>
+    void ToStringBase(string_type & result) const
+    {
+        if( IsNan() )
+        {
+            result = "NaN";
+            return;
+        }
+
+        value.ToStringBase(result, 10, IsSign());
+
+        if( dec_digits > 0 )
+        {
+            size_t size = result.size();
+
+            if( IsSign() && size > 0 )
+                size -= 1;
+
+            if( dec_digits >= size )
+            {
+                size_t zeroes = dec_digits - size + 1;
+                size_t start  = IsSign() ? 1 : 0;
+                result.insert(start, zeroes, '0');
+            }
+
+            result.insert(result.end() - dec_digits, '.');
+        }
+    }
+
+
+
+};
+
+
+} // namespace
+
+#endif
+