// ==========================================================
// FreeImage 3 .NET wrapper
// Original FreeImage 3 functions and .NET compatible derived functions
//
// Design and implementation by
// - Jean-Philippe Goerke (jpgoerke@users.sourceforge.net)
// - Carsten Klein (cklein05@users.sourceforge.net)
//
// Contributors:
// - David Boland (davidboland@vodafone.ie)
//
// Main reference : MSDN Knowlede Base
//
// This file is part of FreeImage 3
//
// COVERED CODE IS PROVIDED UNDER THIS LICENSE ON AN "AS IS" BASIS, WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES
// THAT THE COVERED CODE IS FREE OF DEFECTS, MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE
// OR NON-INFRINGING. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE COVERED
// CODE IS WITH YOU. SHOULD ANY COVERED CODE PROVE DEFECTIVE IN ANY RESPECT, YOU (NOT
// THE INITIAL DEVELOPER OR ANY OTHER CONTRIBUTOR) ASSUME THE COST OF ANY NECESSARY
// SERVICING, REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL
// PART OF THIS LICENSE. NO USE OF ANY COVERED CODE IS AUTHORIZED HEREUNDER EXCEPT UNDER
// THIS DISCLAIMER.
//
// Use at your own risk!
// ==========================================================
// ==========================================================
// CVS
// $Revision: 1.5 $
// $Date: 2009/02/27 16:36:23 $
// $Id: FIURational.cs,v 1.5 2009/02/27 16:36:23 cklein05 Exp $
// ==========================================================
using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Diagnostics;
namespace FreeImageAPI
{
///
/// The FIURational structure represents a fraction via two
/// instances which are interpreted as numerator and denominator.
///
///
/// The structure tries to approximate the value of
/// when creating a new instance by using a better algorithm than FreeImage does.
///
/// The structure implements the following operators:
/// +, ++, --, ==, != , >, >==, <, <== and ~ (which switches nominator and denomiator).
///
/// The structure can be converted into all .NET standard types either implicit or
/// explicit.
///
[Serializable, StructLayout(LayoutKind.Sequential), ComVisible(true)]
public struct FIURational : IConvertible, IComparable, IFormattable, IComparable, IEquatable
{
[DebuggerBrowsable(DebuggerBrowsableState.Never)]
private uint numerator;
[DebuggerBrowsable(DebuggerBrowsableState.Never)]
private uint denominator;
///
/// Represents the largest possible value of . This field is constant.
///
public static readonly FIURational MaxValue = new FIURational(UInt32.MaxValue, 1u);
///
/// Represents the smallest possible value of . This field is constant.
///
public static readonly FIURational MinValue = new FIURational(0u, 1u);
///
/// Represents the smallest positive value greater than zero. This field is constant.
///
public static readonly FIURational Epsilon = new FIURational(1u, UInt32.MaxValue);
///
/// Initializes a new instance based on the specified parameters.
///
/// The numerator.
/// The denominator.
public FIURational(uint n, uint d)
{
numerator = n;
denominator = d;
Normalize();
}
///
/// Initializes a new instance based on the specified parameters.
///
/// The tag to read the data from.
public unsafe FIURational(FITAG tag)
{
switch (FreeImage.GetTagType(tag))
{
case FREE_IMAGE_MDTYPE.FIDT_RATIONAL:
uint* pvalue = (uint*)FreeImage.GetTagValue(tag);
numerator = pvalue[0];
denominator = pvalue[1];
Normalize();
return;
default:
throw new ArgumentException("tag");
}
}
///
///Initializes a new instance based on the specified parameters.
///
/// The value to convert into a fraction.
///
/// cannot be converted into a fraction
/// represented by two unsigned integer values.
public FIURational(decimal value)
{
try
{
if (value < 0)
{
throw new OverflowException("value");
}
try
{
int[] contFract = CreateContinuedFraction(value);
CreateFraction(contFract, out numerator, out denominator);
Normalize();
}
catch
{
numerator = 0;
denominator = 1;
}
if (Math.Abs(((decimal)numerator / (decimal)denominator) - value) > 0.0001m)
{
int maxDen = (Int32.MaxValue / (int)value) - 2;
maxDen = maxDen < 10000 ? maxDen : 10000;
ApproximateFraction(value, maxDen, out numerator, out denominator);
Normalize();
if (Math.Abs(((decimal)numerator / (decimal)denominator) - value) > 0.0001m)
{
throw new OverflowException("Unable to convert value into a fraction");
}
}
Normalize();
}
catch (Exception ex)
{
throw new OverflowException("Unable to calculate fraction.", ex);
}
}
///
/// The numerator of the fraction.
///
public uint Numerator
{
get { return numerator; }
}
///
/// The denominator of the fraction.
///
public uint Denominator
{
get { return denominator; }
}
///
/// Returns the truncated value of the fraction.
///
///
public int Truncate()
{
return denominator > 0 ? (int)(numerator / denominator) : 0;
}
///
/// Returns whether the fraction is representing an integer value.
///
public bool IsInteger
{
get
{
return (denominator == 1 ||
(denominator != 0 && (numerator % denominator == 0)) ||
(denominator == 0 && numerator == 0));
}
}
///
/// Calculated the greatest common divisor of 'a' and 'b'.
///
private static ulong Gcd(ulong a, ulong b)
{
ulong r;
while (b > 0)
{
r = a % b;
a = b;
b = r;
}
return a;
}
///
/// Calculated the smallest common multiple of 'a' and 'b'.
///
private static ulong Scm(uint n, uint m)
{
return (ulong)n * (ulong)m / Gcd(n, m);
}
///
/// Normalizes the fraction.
///
private void Normalize()
{
if (denominator == 0)
{
numerator = 0;
denominator = 1;
return;
}
if (numerator != 1 && denominator != 1)
{
uint common = (uint)Gcd(numerator, denominator);
if (common != 1 && common != 0)
{
numerator /= common;
denominator /= common;
}
}
}
///
/// Normalizes a fraction.
///
private static void Normalize(ref ulong numerator, ref ulong denominator)
{
if (denominator == 0)
{
numerator = 0;
denominator = 1;
}
else if (numerator != 1 && denominator != 1)
{
ulong common = Gcd(numerator, denominator);
if (common != 1)
{
numerator /= common;
denominator /= common;
}
}
}
///
/// Returns the digits after the point.
///
private static int GetDigits(decimal value)
{
int result = 0;
value -= decimal.Truncate(value);
while (value != 0)
{
value *= 10;
value -= decimal.Truncate(value);
result++;
}
return result;
}
///
/// Creates a continued fraction of a decimal value.
///
private static int[] CreateContinuedFraction(decimal value)
{
int precision = GetDigits(value);
decimal epsilon = 0.0000001m;
List list = new List();
value = Math.Abs(value);
byte b = 0;
list.Add((int)value);
value -= ((int)value);
while (value != 0m)
{
if (++b == byte.MaxValue || value < epsilon)
{
break;
}
value = 1m / value;
if (Math.Abs((Math.Round(value, precision - 1) - value)) < epsilon)
{
value = Math.Round(value, precision - 1);
}
list.Add((int)value);
value -= ((int)value);
}
return list.ToArray();
}
///
/// Creates a fraction from a continued fraction.
///
private static void CreateFraction(int[] continuedFraction, out uint numerator, out uint denominator)
{
numerator = 1;
denominator = 0;
uint temp;
for (int i = continuedFraction.Length - 1; i > -1; i--)
{
temp = numerator;
numerator = (uint)(continuedFraction[i] * numerator + denominator);
denominator = temp;
}
}
///
/// Tries 'brute force' to approximate with a fraction.
///
private static void ApproximateFraction(decimal value, int maxDen, out uint num, out uint den)
{
num = 0;
den = 0;
decimal bestDifference = 1m;
decimal currentDifference = -1m;
int digits = GetDigits(value);
if (digits <= 9)
{
uint mul = 1;
for (int i = 1; i <= digits; i++)
{
mul *= 10;
}
if (mul <= maxDen)
{
num = (uint)(value * mul);
den = mul;
return;
}
}
for (uint u = 1; u <= maxDen; u++)
{
uint numerator = (uint)Math.Floor(value * (decimal)u + 0.5m);
currentDifference = Math.Abs(value - (decimal)numerator / (decimal)u);
if (currentDifference < bestDifference)
{
num = numerator;
den = u;
bestDifference = currentDifference;
}
}
}
///
/// Converts the numeric value of the object
/// to its equivalent string representation.
///
/// The string representation of the value of this instance.
public override string ToString()
{
return ((IConvertible)this).ToDouble(null).ToString();
}
///
/// Tests whether the specified object is a structure
/// and is equivalent to this structure.
///
/// The object to test.
/// true if is a structure
/// equivalent to this structure; otherwise, false.
public override bool Equals(object obj)
{
return ((obj is FIURational) && (this == ((FIURational)obj)));
}
///
/// Returns a hash code for this structure.
///
/// An integer value that specifies the hash code for this .
public override int GetHashCode()
{
return base.GetHashCode();
}
#region Operators
///
/// Standard implementation of the operator.
///
public static FIURational operator +(FIURational value)
{
return value;
}
///
/// Returns the reciprocal value of this instance.
///
public static FIURational operator ~(FIURational value)
{
uint temp = value.denominator;
value.denominator = value.numerator;
value.numerator = temp;
value.Normalize();
return value;
}
///
/// Standard implementation of the operator.
///
public static FIURational operator ++(FIURational value)
{
checked
{
value.numerator += value.denominator;
}
return value;
}
///
/// Standard implementation of the operator.
///
public static FIURational operator --(FIURational value)
{
checked
{
value.numerator -= value.denominator;
}
return value;
}
///
/// Standard implementation of the operator.
///
public static FIURational operator +(FIURational left, FIURational right)
{
ulong numerator = 0;
ulong denominator = Scm(left.denominator, right.denominator);
numerator = (left.numerator * (denominator / left.denominator)) +
(right.numerator * (denominator / right.denominator));
Normalize(ref numerator, ref denominator);
checked
{
return new FIURational((uint)numerator, (uint)denominator);
}
}
///
/// Standard implementation of the operator.
///
public static FIURational operator -(FIURational left, FIURational right)
{
checked
{
if (left.denominator != right.denominator)
{
uint denom = left.denominator;
left.numerator *= right.denominator;
left.denominator *= right.denominator;
right.numerator *= denom;
right.denominator *= denom;
}
left.numerator -= right.numerator;
left.Normalize();
return left;
}
}
///
/// Standard implementation of the operator.
///
public static FIURational operator *(FIURational left, FIURational r2)
{
ulong numerator = left.numerator * r2.numerator;
ulong denominator = left.denominator * r2.denominator;
Normalize(ref numerator, ref denominator);
checked
{
return new FIURational((uint)numerator, (uint)denominator);
}
}
///
/// Standard implementation of the operator.
///
public static FIURational operator /(FIURational left, FIURational right)
{
uint temp = right.denominator;
right.denominator = right.numerator;
right.numerator = temp;
return left * right;
}
///
/// Standard implementation of the operator.
///
public static FIURational operator %(FIURational left, FIURational right)
{
right.Normalize();
if (Math.Abs(right.numerator) < right.denominator)
return new FIURational(0, 0);
int div = (int)(left / right);
return left - (right * div);
}
///
/// Standard implementation of the operator.
///
public static bool operator ==(FIURational left, FIURational right)
{
left.Normalize();
right.Normalize();
return (left.numerator == right.numerator) && (left.denominator == right.denominator);
}
///
/// Standard implementation of the operator.
///
public static bool operator !=(FIURational left, FIURational right)
{
left.Normalize();
right.Normalize();
return (left.numerator != right.numerator) || (left.denominator != right.denominator);
}
///
/// Standard implementation of the operator.
///
public static bool operator >(FIURational left, FIURational right)
{
ulong denominator = Scm(left.denominator, right.denominator);
return (left.numerator * (denominator / left.denominator)) >
(right.numerator * (denominator / right.denominator));
}
///
/// Standard implementation of the operator.
///
public static bool operator <(FIURational left, FIURational right)
{
ulong denominator = Scm(left.denominator, right.denominator);
return (left.numerator * (denominator / left.denominator)) <
(right.numerator * (denominator / right.denominator));
}
///
/// Standard implementation of the operator.
///
public static bool operator >=(FIURational left, FIURational right)
{
ulong denominator = Scm(left.denominator, right.denominator);
return (left.numerator * (denominator / left.denominator)) >=
(right.numerator * (denominator / right.denominator));
}
///
/// Standard implementation of the operator.
///
public static bool operator <=(FIURational left, FIURational right)
{
ulong denominator = Scm(left.denominator, right.denominator);
return (left.numerator * (denominator / left.denominator)) <=
(right.numerator * (denominator / right.denominator));
}
#endregion
#region Conversions
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator bool(FIURational value)
{
return (value.numerator != 0);
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator byte(FIURational value)
{
return (byte)(double)value;
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator char(FIURational value)
{
return (char)(double)value;
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static implicit operator decimal(FIURational value)
{
return value.denominator == 0 ? 0m : (decimal)value.numerator / (decimal)value.denominator;
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static implicit operator double(FIURational value)
{
return value.denominator == 0 ? 0d : (double)value.numerator / (double)value.denominator;
}
///
/// Converts the value of a structure to an structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator short(FIURational value)
{
return (short)(double)value;
}
///
/// Converts the value of a structure to an structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator int(FIURational value)
{
return (int)(double)value;
}
///
/// Converts the value of a structure to an structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator long(FIURational value)
{
return (byte)(double)value;
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static implicit operator float(FIURational value)
{
return value.denominator == 0 ? 0f : (float)value.numerator / (float)value.denominator;
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator sbyte(FIURational value)
{
return (sbyte)(double)value;
}
///
/// Converts the value of a structure to an structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator ushort(FIURational value)
{
return (ushort)(double)value;
}
///
/// Converts the value of a structure to an structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator uint(FIURational value)
{
return (uint)(double)value;
}
///
/// Converts the value of a structure to an structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator ulong(FIURational value)
{
return (ulong)(double)value;
}
//
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator FIURational(bool value)
{
return new FIURational(value ? 1u : 0u, 1u);
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static implicit operator FIURational(byte value)
{
return new FIURational(value, 1);
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static implicit operator FIURational(char value)
{
return new FIURational(value, 1);
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator FIURational(decimal value)
{
return new FIURational(value);
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator FIURational(double value)
{
return new FIURational((decimal)value);
}
///
/// Converts the value of an structure to a structure.
///
/// An structure.
/// A new instance of initialized to .
public static implicit operator FIURational(short value)
{
return new FIURational((uint)value, 1u);
}
///
/// Converts the value of an structure to a structure.
///
/// An structure.
/// A new instance of initialized to .
public static implicit operator FIURational(int value)
{
return new FIURational((uint)value, 1u);
}
///
/// Converts the value of an structure to a structure.
///
/// An structure.
/// A new instance of initialized to .
public static explicit operator FIURational(long value)
{
return new FIURational((uint)value, 1u);
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static implicit operator FIURational(sbyte value)
{
return new FIURational((uint)value, 1u);
}
///
/// Converts the value of a structure to a structure.
///
/// A structure.
/// A new instance of initialized to .
public static explicit operator FIURational(float value)
{
return new FIURational((decimal)value);
}
///
/// Converts the value of an structure to a structure.
///
/// An structure.
/// A new instance of initialized to .
public static implicit operator FIURational(ushort value)
{
return new FIURational(value, 1);
}
///
/// Converts the value of an structure to a structure.
///
/// An structure.
/// A new instance of initialized to .
public static explicit operator FIURational(uint value)
{
return new FIURational(value, 1u);
}
///
/// Converts the value of an structure to a structure.
///
/// An structure.
/// A new instance of initialized to .
public static explicit operator FIURational(ulong value)
{
return new FIURational((uint)value, 1u);
}
#endregion
#region IConvertible Member
TypeCode IConvertible.GetTypeCode()
{
return TypeCode.Double;
}
bool IConvertible.ToBoolean(IFormatProvider provider)
{
return (bool)this;
}
byte IConvertible.ToByte(IFormatProvider provider)
{
return (byte)this;
}
char IConvertible.ToChar(IFormatProvider provider)
{
return (char)this;
}
DateTime IConvertible.ToDateTime(IFormatProvider provider)
{
return Convert.ToDateTime(((IConvertible)this).ToDouble(provider));
}
decimal IConvertible.ToDecimal(IFormatProvider provider)
{
return this;
}
double IConvertible.ToDouble(IFormatProvider provider)
{
return this;
}
short IConvertible.ToInt16(IFormatProvider provider)
{
return (short)this;
}
int IConvertible.ToInt32(IFormatProvider provider)
{
return (int)this;
}
long IConvertible.ToInt64(IFormatProvider provider)
{
return (long)this;
}
sbyte IConvertible.ToSByte(IFormatProvider provider)
{
return (sbyte)this;
}
float IConvertible.ToSingle(IFormatProvider provider)
{
return this;
}
string IConvertible.ToString(IFormatProvider provider)
{
return ToString(((double)this).ToString(), provider);
}
object IConvertible.ToType(Type conversionType, IFormatProvider provider)
{
return Convert.ChangeType(((IConvertible)this).ToDouble(provider), conversionType, provider);
}
ushort IConvertible.ToUInt16(IFormatProvider provider)
{
return (ushort)this;
}
uint IConvertible.ToUInt32(IFormatProvider provider)
{
return (uint)this;
}
ulong IConvertible.ToUInt64(IFormatProvider provider)
{
return (ulong)this;
}
#endregion
#region IComparable Member
///
/// Compares this instance with a specified .
///
/// An object to compare with this instance.
/// A 32-bit signed integer indicating the lexical relationship between the two comparands.
/// is not a .
public int CompareTo(object obj)
{
if (obj == null)
{
return 1;
}
if (!(obj is FIURational))
{
throw new ArgumentException();
}
return CompareTo((FIURational)obj);
}
#endregion
#region IFormattable Member
///
/// Formats the value of the current instance using the specified format.
///
/// The String specifying the format to use.
/// The IFormatProvider to use to format the value.
/// A String containing the value of the current instance in the specified format.
public string ToString(string format, IFormatProvider formatProvider)
{
if (format == null)
{
format = "";
}
return String.Format(formatProvider, format, ((IConvertible)this).ToDouble(formatProvider));
}
#endregion
#region IEquatable Member
///
/// Tests whether the specified structure is equivalent to this structure.
///
/// A structure to compare to this instance.
/// true if is a structure
/// equivalent to this structure; otherwise, false.
public bool Equals(FIURational other)
{
return (this == other);
}
#endregion
#region IComparable Member
///
/// Compares this instance with a specified object.
///
/// A to compare.
/// A signed number indicating the relative values of this instance
/// and .
public int CompareTo(FIURational other)
{
FIURational difference = this - other;
difference.Normalize();
if (difference.numerator > 0) return 1;
if (difference.numerator < 0) return -1;
else return 0;
}
#endregion
}
}