/// <summary>
/// Tries to parse the JFIF APP0 header
/// See http://en.wikipedia.org/wiki/JFIF
/// </summary>
private bool TryParseJFIF(byte[] data)
{
FJBinaryReader reader = new FJBinaryReader(new MemoryStream(data));
int length = data.Length + 2; // Data & length
if (!(length >= JFIF_FIXED_LENGTH))
{
return(false); // Header's too small.
}
byte[] identifier = new byte[5];
reader.Read(identifier, 0, identifier.Length);
if (identifier[0] != JPEGMarker.JFIF_J ||
identifier[1] != JPEGMarker.JFIF_F ||
identifier[2] != JPEGMarker.JFIF_I ||
identifier[3] != JPEGMarker.JFIF_F ||
identifier[4] != JPEGMarker.X00)
{
return(false); // Incorrect bytes
}
majorVersion = reader.ReadByte();
minorVersion = reader.ReadByte();
if (majorVersion != MAJOR_VERSION ||
(majorVersion == MAJOR_VERSION &&
minorVersion > MINOR_VERSION)) // changed from <
{
return(false); // Unsupported version
}
Units = (UnitType)reader.ReadByte();
if (Units != UnitType.None &&
Units != UnitType.Inches &&
Units != UnitType.Centimeters)
{
return(false); // Invalid units
}
XDensity = reader.ReadShort();
YDensity = reader.ReadShort();
Xthumbnail = reader.ReadByte();
Ythumbnail = reader.ReadByte();
// 3 * for RGB data
int thumbnailLength = 3 * Xthumbnail * Ythumbnail;
if (length > JFIF_FIXED_LENGTH &&
thumbnailLength != length - JFIF_FIXED_LENGTH)
{
return(false); // Thumbnail fields invalid
}
if (thumbnailLength > 0)
{
thumbnail = new byte[thumbnailLength];
if (reader.Read(thumbnail, 0, thumbnailLength) != thumbnailLength)
{
return(false); // Thumbnail data was missing!
}
}
return(true);
}
/// <summary>
/// Tries to parse the JFIF APP0 header
/// See http://en.wikipedia.org/wiki/JFIF
/// </summary>
private bool TryParseJFIF(byte[] data)
{
FJBinaryReader reader = new FJBinaryReader(new MemoryStream(data));
int length = data.Length + 2; // Data & length
if (!(length >= JFIF_FIXED_LENGTH))
return false; // Header's too small.
byte[] identifier = new byte[5];
reader.Read(identifier, 0, identifier.Length);
if (identifier[0] != JPEGMarker.JFIF_J
|| identifier[1] != JPEGMarker.JFIF_F
|| identifier[2] != JPEGMarker.JFIF_I
|| identifier[3] != JPEGMarker.JFIF_F
|| identifier[4] != JPEGMarker.X00)
return false; // Incorrect bytes
majorVersion = reader.ReadByte();
minorVersion = reader.ReadByte();
if (majorVersion != MAJOR_VERSION
|| (majorVersion == MAJOR_VERSION
&& minorVersion > MINOR_VERSION)) // changed from <
return false; // Unsupported version
Units = (UnitType)reader.ReadByte();
if (Units != UnitType.None &&
Units != UnitType.Inches &&
Units != UnitType.Centimeters)
return false; // Invalid units
XDensity = reader.ReadShort();
YDensity = reader.ReadShort();
Xthumbnail = reader.ReadByte();
Ythumbnail = reader.ReadByte();
// 3 * for RGB data
int thumbnailLength = 3 * Xthumbnail * Ythumbnail;
if (length > JFIF_FIXED_LENGTH
&& thumbnailLength != length - JFIF_FIXED_LENGTH)
return false; // Thumbnail fields invalid
if (thumbnailLength > 0)
{
thumbnail = new byte[thumbnailLength];
if (reader.Read(thumbnail, 0, thumbnailLength) != thumbnailLength)
return false; // Thumbnail data was missing!
}
return true;
}
