Inform 7 compiler crashes on too long image descriptions

Technical Development
1

When the combined image descriptions become too large, the Inform 6M62 Compiler will crash at the cBlorb stage. At least I think that is what is happening. Compiler finished with code 11 is the only error message.

There is probably a way to pack descriptions manually with blorbtool.py, but it seems like a lot of work.

Test case here:

2

code 11’s an Inform 6 message, I thought. What version are you using on what platform? I can compile your image-descriptions branch on Linux with Inform 6.34. But then I get a segfault on trying to cBlorb it. Weirder, with the cBlorb 1.2 I get along with gnome-inform7’s gtk3 branch, I don’t get a lot of info:

! cBlorb 1.2 [executing on Tuesday 6 April 2021 at 00:28.21]
! The blorb spell (safely protect a small object as though in a strong box).
! Auxiliary file: <Counterfeit Monkey.materials/Customs-Poster-Big.png> = <Customs Poster>
! Auxiliary file: <Counterfeit Monkey.materials/DCLbig.png> = <DCL Advertisement>
! Auxiliary file: <Counterfeit Monkey.materials/Atlantida.png> = <Atlantida Poster>
Segmentation fault

Building the cBlorb source from github, though, I get:

Counterfeit Monkey.inform/Release.blurb, line 18: Error: not a valid blurb command: 'picture 3 "Counterfeit Monkey.materials/Figures/grey-nw.png" "dim northwest"'
Counterfeit Monkey.inform/Release.blurb, line 19: Error: not a valid blurb command: 'picture 4 "Counterfeit Monkey.materials/Figures/grey-n.png" "dim north"'
[...]
Counterfeit Monkey.inform/Release.blurb, line 75: Error: not a valid blurb command: 'picture 60 "Counterfeit Monkey.materials/Figures/map-sigil-street.png" "A city map
made out of letters in different typefaces. The player location is marked with an At sign at Sigil Street near the southwest corner of the map."'
Counterfeit Monkey.inform/Release.blurb, line 76: Error: placeholder text too long
Counterfeit Monkey.inform/Release.blurb, line 76: Error: not a valid blurb command: 'picture 61 "Counterfeit Monkey.materials/Figures/map-ampersand-bend.png" "A city ma
p made out of letters in different typefaces. The player location is marked with an At sign at Ampersand Bend near the southwest corner of the map."'
Segmentation fault
3

well, I guess the different outputs aren’t so strange. The source code varies in lots of ways, though both identify as cBlorb 1.2.

4

The Windows IDE at least offers the following stack trace:

Process failed, stack backtrace:
Exception code 0xc0000005
cblorb!write_blorb_file() at cBlorb\Chapter 2\Blorb Writer.w line 509
cblorb!main() at cBlorb\Chapter 1\Main.w line 104
cblorb!__tmainCRTStartup() at \usr\src\debug\mingw64-x86_64-runtime-7.0.0-1\crt\crtexe.c line 341
cblorb!mainCRTStartup() at \usr\src\debug\mingw64-x86_64-runtime-7.0.0-1\crt\crtexe.c line 225
KERNEL32!BaseThreadInitThunk()
ntdll!RtlUserThreadStart()

The referenced line is: if (chunk->index_entry) { ... }. Poking at it with a debugger shows that an invalid chunk_metadata structure does somehow manage to sneak into the list, but as of now I have no idea how it gets there.

5

gnome-inform7’s cBlorb code is apparently more recent than this cBlorb github repo: the latter doesn’t have the resource descriptions added in 2014. So there’s nothing useful to be gleaned from my second block of error messages above.

6

David Griffith’s GitLab cBlorb repository seems to be a little more recent, last updated in September 2015.

EDIT 2: Nope, the GitLab and Github repos are identical.

EDIT: This seems to produce the same error messages as your Github build, unlike the built-in version.

It is of course entirely possible that this is all caused by some copy-and-paste error of mine in the Counterfeit Monkey source code, but after having looked through the relevant commit several times, I can’t seem to find anything.

7

Despite the date, the gitlab repo’s definition of legal_Blorb_chunk_types in Blorb Writer.w doesn’t have RDes (resource description).

8

I don’t have the full source setup. Could someone post the Release.blurb that this is operating on? That will make it easier to check into.

9

Here’s a gist of my Release.blurb which with any luck is the same as @Angstsmurf 's (other than the pathname prefix)

10

I don’t think so. I added this to add_chunk_to_blorb:

printf("add_chunk_to_blorb id %s, resource_num %d, supplied_filename %s, index %s, length %d\n",id,resource_num,supplied_filename,index,length);

With the image-descriptions branch’s Map Declarations.i7x we see this before the segfault:

add_chunk_to_blorb id RDes, resource_num 0, supplied_filename (null), index (null), length 12450

Then I whittled down the descriptions by cutting some of the common text.

It segfaulted again at 10800

add_chunk_to_blorb id RDes, resource_num 0, supplied_filename (null), index (null), length 10800

But then succeeded at 9435:

add_chunk_to_blorb id RDes, resource_num 0, supplied_filename (null), index (null), length 9435

I’m not seeing an obvious threshold between 9435 and 10800 that would account for this, but I haven’t looked that closely.

1 Like
11

Here is my Release.blurb.

Before anyone mentions it: this is a work in progress, so I am aware that many of the descriptions do not in fact describe the correct image.