Copy & paste as SNBT

[Vftdan]

Implement copying & pasting of subtrees as text, that should be valid SNBT (the syntax used in command blocks, but I have not tested).

Current limitations

• The only pasting option available is replacement of an existing tag; old & new tag types must much, so new tags should be created, named & set the the correct type manually
• Recovery from end of input while checking number type may be incomlete, so you may want add a trailing space when pasting double/int tags (or just use Edit value... instead)
• Not tested very much (especially different *ArrayTags), so there may be other problems
• It currently uses old clipboard API, pasting falls back to prompt

Closes #5, #15

[iRath96]

Why do you use htonl here?

[Vftdan]

Why do you use htonl here?

I just copied this line from here:

webNBT/nbt-utils/nbt_utils.cpp

Lines 211 to 214 in 1ec2913

	wr_payload(ByteArrayTag) {
	uint32_t count = htonl(value.count);
	stream.write((char *)&count, 4);
	stream.write((char *)value.data.get(), value.count); }

[iRath96]

@Vftdan It is used there because NBT requires that integer values are serialized in network (big endian) order. That is not necessarily the endianness of the host system (which usually is little endian). Hence the conversion from host to network (hton).

When you are doing this before your for-loop, however, very nasty things happen if the host order and network order mismatch. An array that has only one element (value.count = 0x00000001) will cause your local count variable to have the value 0x01000000, causing your loop to run 16777216 times even though there is only one element.

[iRath96]

Do we really need to escape single quotes given that your output is always encapsulated by double quotes?

[Vftdan]

No, but I feel like it is less likely to cause problems if somebody would write a bad parser

[iRath96]

@Vftdan the problem is that Minecraft will emit the error Invalid escape sequence \' when you escape single quotes.

[iRath96]

There seems to be a problem with copying doubles. They are exported in hexadecimal notation, which they are not supposed to be afaik.

[iRath96]

The error message when pasting something of incorrect type is confusing. It says "Parse error at position 0" even though the pasted content is syntactically correct. Perhaps it should say something along the lines of, e.g., "Cannot paste content of type 'Double' into property of type 'Long'".

In the future, it would be cool to automatically cast at some of the types (in particular among the numerical types). But for now we can live without this :-)

[iRath96]

The first call to stream.setf should not use std::ios::floatfield as first argument. You should be using std::ios::fixed here as well, as otherwise doubles are emitted in hexadecimal notation, which Minecraft is unable to parse.