public DirectoryList Extract(SequentialReader reader)
{
var directory = new PsdHeaderDirectory();
// FILE HEADER SECTION
try
{
var signature = reader.GetInt32();
var version = reader.GetUInt16();
if (signature != 0x38425053)
{
// "8BPS"
directory.AddError("Invalid PSD file signature");
}
else if (version != 1 && version != 2)
{
directory.AddError("Invalid PSD file version (must be 1 or 2)");
}
else
{
// 6 reserved bytes are skipped here. They should be zero.
reader.Skip(6);
var channelCount = reader.GetUInt16();
directory.Set(PsdHeaderDirectory.TagChannelCount, channelCount);
// even though this is probably an unsigned int, the max height in practice is 300,000
var imageHeight = reader.GetInt32();
directory.Set(PsdHeaderDirectory.TagImageHeight, imageHeight);
// even though this is probably an unsigned int, the max width in practice is 300,000
var imageWidth = reader.GetInt32();
directory.Set(PsdHeaderDirectory.TagImageWidth, imageWidth);
var bitsPerChannel = reader.GetUInt16();
directory.Set(PsdHeaderDirectory.TagBitsPerChannel, bitsPerChannel);
var colorMode = reader.GetUInt16();
directory.Set(PsdHeaderDirectory.TagColorMode, colorMode);
}
}
catch (IOException)
{
directory.AddError("Unable to read PSD header");
}
if (directory.HasError)
{
return new Directory[] { directory }
}
;
IEnumerable <Directory>?photoshopDirectories = null;
try
{
// COLOR MODE DATA SECTION
// Only indexed color and duotone (see the mode field in the File header section) have color mode data.
// For all other modes, this section is just the 4-byte length field, which is set to zero.
//
// Indexed color images: length is 768; color data contains the color table for the image,
// in non-interleaved order.
// Duotone images: color data contains the duotone specification (the format of which is not documented).
// Other applications that read Photoshop files can treat a duotone image as a gray image,
// and just preserve the contents of the duotone information when reading and writing the
// file.
var colorModeSectionLength = reader.GetUInt32();
reader.Skip(colorModeSectionLength);
// IMAGE RESOURCES SECTION
var imageResourcesSectionLength = reader.GetUInt32();
Debug.Assert(imageResourcesSectionLength <= int.MaxValue);
photoshopDirectories = new PhotoshopReader().Extract(reader, (int)imageResourcesSectionLength);
}
catch (IOException)
{
}
var directories = new List <Directory> {
directory
};
if (photoshopDirectories != null)
{
directories.AddRange(photoshopDirectories);
}
// LAYER AND MASK INFORMATION SECTION (skipped)
// IMAGE DATA SECTION (skipped)
return(directories);
}
}
Extract([NotNull] SequentialReader reader)
{
var directory = new PsdHeaderDirectory();
// FILE HEADER SECTION
try
{
var signature = reader.GetInt32();
var version = reader.GetUInt16();
if (signature != 0x38425053)
{
// "8BPS"
directory.AddError("Invalid PSD file signature");
}
else if (version != 1 && version != 2)
{
directory.AddError("Invalid PSD file version (must be 1 or 2)");
}
else
{
// 6 reserved bytes are skipped here. They should be zero.
reader.Skip(6);
var channelCount = reader.GetUInt16();
directory.Set(PsdHeaderDirectory.TagChannelCount, channelCount);
// even though this is probably an unsigned int, the max height in practice is 300,000
var imageHeight = reader.GetInt32();
directory.Set(PsdHeaderDirectory.TagImageHeight, imageHeight);
// even though this is probably an unsigned int, the max width in practice is 300,000
var imageWidth = reader.GetInt32();
directory.Set(PsdHeaderDirectory.TagImageWidth, imageWidth);
var bitsPerChannel = reader.GetUInt16();
directory.Set(PsdHeaderDirectory.TagBitsPerChannel, bitsPerChannel);
var colorMode = reader.GetUInt16();
directory.Set(PsdHeaderDirectory.TagColorMode, colorMode);
}
}
catch (IOException)
{
directory.AddError("Unable to read PSD header");
}
if (directory.HasError)
return new[] { directory };
IEnumerable<Directory> photoshopDirectories = null;
try
{
// COLOR MODE DATA SECTION
// Only indexed color and duotone (see the mode field in the File header section) have color mode data.
// For all other modes, this section is just the 4-byte length field, which is set to zero.
//
// Indexed color images: length is 768; color data contains the color table for the image,
// in non-interleaved order.
// Duotone images: color data contains the duotone specification (the format of which is not documented).
// Other applications that read Photoshop files can treat a duotone image as a gray image,
// and just preserve the contents of the duotone information when reading and writing the
// file.
var colorModeSectionLength = reader.GetUInt32();
reader.Skip(colorModeSectionLength);
// IMAGE RESOURCES SECTION
var imageResourcesSectionLength = reader.GetUInt32();
Debug.Assert(imageResourcesSectionLength <= int.MaxValue);
photoshopDirectories = new PhotoshopReader().Extract(reader, (int)imageResourcesSectionLength);
}
catch (IOException)
{
}
var directories = new List<Directory> { directory };
if (photoshopDirectories != null)
directories.AddRange(photoshopDirectories);
// LAYER AND MASK INFORMATION SECTION (skipped)
// IMAGE DATA SECTION (skipped)
return directories;
}
