/// <summary>
/// Default case that adds comment with keyword to directory
/// </summary>
/// <param name="directory">EpsDirectory to add extracted data to</param>
/// <param name="name">String that holds name of current comment</param>
/// <param name="value">String that holds value of current comment</param>
private void AddToDirectory(EpsDirectory directory, string name, string value)
{
if (!EpsDirectory.TagIntegerMap.ContainsKey(name))
{
return;
}
var tag = EpsDirectory.TagIntegerMap[name];
switch (tag)
{
case EpsDirectory.TagImageData:
ExtractImageData(directory, value);
break;
case EpsDirectory.TagContinueLine:
directory.Set(_previousTag, directory.GetString(_previousTag) + " " + value);
break;
default:
if (EpsDirectory.TagNameMap.ContainsKey(tag) && !directory.ContainsTag(tag))
{
directory.Set(tag, value);
_previousTag = tag;
}
else
{
// Set previous tag to an Integer that doesn't exist in EpsDirectory
_previousTag = 0;
}
break;
}
_previousTag = tag;
}
/// <summary>
/// Main method that parses all comments and then distributes data extraction among other methods that parse the
/// rest of file and store encountered data in metadata(if there exists an entry in EpsDirectory
/// for the found data). Reads until a begin data/binary comment is found or reader's estimated
/// available data has run out (or AI09 End Private Data). Will extract data from normal EPS comments, Photoshop, ICC, and XMP.
/// </summary>
/// <param name="directory"></param>
/// <param name="directories">list to add directory to and extracted data</param>
/// <param name="reader"></param>
private void Extract(EpsDirectory directory, List <Directory> directories, SequentialReader reader)
{
var line = new StringBuilder();
while (true)
{
line.Length = 0;
// Read the next line, excluding any trailing newline character
// Note that for Windows-style line endings ("\r\n") the outer loop will be run a second time with an empty
// string, which is fine.
while (true)
{
char c = (char)reader.GetByte();
if (c == '\r' || c == '\n')
{
break;
}
line.Append(c);
}
// Stop when we hit a line that is not a comment
if (line.Length != 0 && line[0] != '%')
{
break;
}
string name;
// ':' signifies there is an associated keyword (should be put in directory)
// otherwise, the name could be a marker
int colonIndex = line.IndexOf(':');
if (colonIndex != -1)
{
name = line.ToString(0, colonIndex).Trim();
var value = line.ToString(colonIndex + 1, line.Length - (colonIndex + 1)).Trim();
AddToDirectory(directory, name, value);
}
else
{
name = line.ToString().Trim();
}
// Some comments will both have a value and signify a new block to follow
if (name.Equals("%BeginPhotoshop"))
{
ExtractPhotoshopData(directories, reader);
}
else if (name.Equals("%%BeginICCProfile"))
{
ExtractIccData(directories, reader);
}
else if (name.Equals("%begin_xml_packet"))
{
ExtractXmpData(directories, reader);
}
}
}
/// <summary>
/// Parses '%ImageData' comment which holds several values including width in px,
/// height in px and color type.
/// </summary>
private static void ExtractImageData(EpsDirectory directory, string imageData)
{
// %ImageData: 1000 1000 8 3 1 1000 7 "beginimage"
directory.Set(EpsDirectory.TagImageData, imageData.Trim());
var imageDataParts = imageData.Split(' ');
int width = int.Parse(imageDataParts[0]);
int height = int.Parse(imageDataParts[1]);
int colorType = int.Parse(imageDataParts[3]);
// Only add values that are not already present
if (!directory.ContainsTag(EpsDirectory.TagImageWidth))
{
directory.Set(EpsDirectory.TagImageWidth, width);
}
if (!directory.ContainsTag(EpsDirectory.TagImageHeight))
{
directory.Set(EpsDirectory.TagImageHeight, height);
}
if (!directory.ContainsTag(EpsDirectory.TagColorType))
{
directory.Set(EpsDirectory.TagColorType, colorType);
}
if (!directory.ContainsTag(EpsDirectory.TagRamSize))
{
int bytesPerPixel = colorType switch
{
1 => 1, // grayscale
2 => 3, // Lab
3 => 3, // RGB
4 => 3, // CMYK
_ => 0
};
if (bytesPerPixel != 0)
{
directory.Set(EpsDirectory.TagRamSize, bytesPerPixel * width * height);
}
}
}
public DirectoryList Extract(Stream inputStream)
{
IndexedReader reader = new IndexedSeekingReader(inputStream);
var directory = new EpsDirectory();
var epsDirectories = new List <Directory>()
{
directory
};
// 0xC5D0D3C6 signifies an EPS Header block which contains 32-bytes of basic information
// 0x25215053 (%!PS) signifies an EPS File and leads straight into the PostScript
int startingPosition = (int)inputStream.Position;
switch (reader.GetInt32(0))
{
case unchecked ((int)0xC5D0D3C6):
reader = reader.WithByteOrder(isMotorolaByteOrder: false);
int postScriptOffset = reader.GetInt32(4);
int postScriptLength = reader.GetInt32(8);
int wmfOffset = reader.GetInt32(12);
int wmfSize = reader.GetInt32(16);
int tifOffset = reader.GetInt32(20);
int tifSize = reader.GetInt32(24);
//int checkSum = reader.getInt32(28);
// Get Tiff/WMF preview data if applicable
if (tifSize != 0)
{
directory.Set(EpsDirectory.TagTiffPreviewSize, tifSize);
directory.Set(EpsDirectory.TagTiffPreviewOffset, tifOffset);
// Get Tiff metadata
try
{
ByteArrayReader byteArrayReader = new(reader.GetBytes(tifOffset, tifSize));
TiffReader.ProcessTiff(byteArrayReader, new PhotoshopTiffHandler(epsDirectories));
}
catch (TiffProcessingException ex)
{
directory.AddError("Unable to process TIFF data: " + ex.Message);
}
}
else if (wmfSize != 0)
{
directory.Set(EpsDirectory.TagWmfPreviewSize, wmfSize);
directory.Set(EpsDirectory.TagWmfPreviewOffset, wmfOffset);
}
// TODO avoid allocating byte array here -- read directly from InputStream
Extract(directory, epsDirectories, new SequentialByteArrayReader(reader.GetBytes(postScriptOffset, postScriptLength)));
break;
case 0x25215053:
inputStream.Position = startingPosition;
Extract(directory, epsDirectories, new SequentialStreamReader(inputStream));
break;
default:
directory.AddError("File type not supported.");
break;
}
return(epsDirectories);
}