private static double ReadRational(IFD_TAGS tag, PropertyItem item)
{
if (item.Id != (int)tag)
{
throw new EXIF_Exception(tag);
}
using (System.IO.MemoryStream mem = new System.IO.MemoryStream(item.Value))
{
System.IO.BinaryReader reader = new System.IO.BinaryReader(mem);
uint nom;
uint denom;
if (item.Type == (int)IFD_TYPES.RATIONAL)
{
nom = reader.ReadUInt32();
denom = reader.ReadUInt32();
if (nom == uint.MaxValue)
{
return(double.PositiveInfinity);
}
if (nom == 0)
{
return(double.NaN);
}
return(nom / denom);
}
else if (item.Type == (int)IFD_TYPES.SHORT)
{
nom = reader.ReadUInt16();
if (nom == ushort.MaxValue)
{
return(double.PositiveInfinity);
}
if (nom == 0)
{
return(double.NaN);
}
return(nom);
}
else
{
throw new EXIF_Exception(tag);
}
}
}
private static int ReadExifInt(IFD_TAGS tag, PropertyItem item)
{
if (item.Id != (int)tag)
{
throw new EXIF_Exception(tag);
}
using (System.IO.MemoryStream mem = new System.IO.MemoryStream(item.Value))
{
System.IO.BinaryReader reader = new System.IO.BinaryReader(mem);
if (item.Type == (int)IFD_TYPES.SHORT)
{
return((int)reader.ReadUInt16());
}
else if (item.Type == (int)IFD_TYPES.LONG)
{
return((int)reader.ReadUInt32());
}
else
{
throw new EXIF_Exception(tag);
}
}
}
public EXIF_Exception(IFD_TAGS tag)
{
this.tag = tag;
}
