Get the layer details of a tiff using LibTiff

HI,
Photoshop layers are stored in tag or field 37724, identified as TIFFTAG_IMAGESOURCEDATA in the latest libtiff.

The data blob shall be an array of uint8_t, and shall be headed by a magic signature that is one of the following null terminated ASCII strings:

• for standard Photoshop files, Adobe Photoshop Document Data Block.
• for Large Document Format (8BPB/PSB) files, Adobe Photoshop Document Data V0002 (the last five characters differ).

After the magic signature, the remainder of the blob is comprised of a series of Additional Layer Information blocks:

• signature: 8BIM (4 bytes)
• block type (4 bytes)
• length of the block (4 bytes, variable, padded to a 4-byte offset)
• data of the block (length as above)

The Technical Notes say that these are the available block types:

• Layr (layer block)
• LMsk (global mask info block)
• Patt (pattern definition block)
• Anno (annotations)
  
  

Has anyone figured how to get the individual layer details using libtiff.

I would really appreciate any thoughts/suggestions on the matter.

Thanks all.