I'd like to figure out which blocks have been modified and what their codes are for a given texture pack. Is that possible? It's got to be right? If I'm working with Dokucraft, how do I know what's what?
Uhm. What? I'm not really sure I understand your question. You don't really modify any code when you do textures, unless you're talking about MCPatcher/Optifine features like Connected Textures or Custom Items.
Let me try again... I guess I didn't explain myself well.
Let me give you an example: I'm using Creative-Node's texture pack. I know that this texture pack has a lot of blocks that have metadata, but I don't know (without exploring the ZIP file itself) which ones have additional textures. For example, block 5 (wood planks) has three or four "flavors" in Minecraft classic, but Creative-Node adds another 5 or so that look like crates of fruit, vegetables, etc.
Another example: If I'm using Dokucraft, which I've heard has over 2,000 different blocks, how do the creators of those fabulous maps know what they have available to them? Do they have to go through the individual folders in the resource pack to figure it out? Is there some table, some cheat sheet, that shows what each block looks like and its data value, including metadata?
So... Is there a way to know the available blocks and the sub-blocks (the metadata) that are currently in use? I've got Not Enough Items ("NEI") installed, and I know it will do a data dump, but the dump does not include metadata. In addition, the blocks specific to the resource pack do not show up in NEI--only those block associated with mods. Is there an easy way for me to figure this out? Is there some mod?
You read very carefully the page where you found the texture pack. I know Doku has a comprehensive list of everything in the Creative Pack, which does indeed add about 2000 blocks to the game. Other than that, no, there's no easy way to tell.