Read a define value untill the end of the line or when it encounters a comment

[Miauwkeru]

• Keeps track of the whitespece between the value and the comment
• Will keep track of a single qouted character

fixes #169

[codecov]

Codecov Report

❌ Patch coverage is 0% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 0.00%. Comparing base (3032ad7) to head (e633073).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
dissect/cstruct/lexer.py	0.00%	28 Missing ⚠️

Additional details and impacted files

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=====================================
  Files         22      22           
  Lines       2798    2881   +83     
=====================================
- Misses      2798    2881   +83     

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[Miauwkeru]

This was the first one that got through all the tests, I will think of a better solution for the quoted string as it will break if you add a single quote somewhere between double quotes

[codspeed-hq]

Merging this PR will not alter performance

✅ 14 untouched benchmarks

---

_{Comparing read-define-value-till-comment (e633073) with main (46b850f)}

[Miauwkeru]

I can replace it with _read_string() however, this does require to escape:

dissect.cstruct/tests/test_parser.py

Line 254 in 3032ad7

#define QUOTES "\'\"a'b\""

oterwise _read_string can't distinguish the quotes from each other. @Schamper is it an idea to always escape the characters? (and document that this is required) If not, I will look for another way

[Schamper]

What about multiline defines with quotes at the end of each (or some) line? Note that I'm not sure how that'd work in C, just a thought. Worth a test.

[Miauwkeru]

What about multiline defines with quotes at the end of each (or some) line? Note that I'm not sure how that'd work in C, just a thought. Worth a test.

Do you mean something like this:

#define HELP " \
#define NLD "

it won't work without the backslash according to some tests with godbolt

[Schamper]

I mean something like this:

#define foo bar \  // comment here
            zomg \  // and here
            yolo

[Miauwkeru]

I mean something like this:

#define foo bar \  // comment here
            zomg \  // and here
            yolo

it will error in that case in c:

main.c:4:13: error: expected identifier or ‘(’ before string constant
    4 |             "zomg" \  // and here
      |             ^~~~~~
main.c:4:20: error: stray ‘\’ in program
    4 |             "zomg" \  // and here
      |                    ^
main.c:3:19: error: stray ‘\’ in program
    3 | #define foo "bar" \  // comment here
      |                   ^
main.c:8:12: note: in expansion of macro ‘foo’
    8 |     printf(foo);

and in cstruct it creates a lexer error for an unexpected \\ character next to zomg

[Schamper]

This is valid C though:

#define foo "bar" /* comment */ \
        "zomg"

Might be nice to at least put something like this in the unit test.

[Miauwkeru]

This is valid C though:

#define foo "bar" /* comment */ \
        "zomg"

Might be nice to at least put something like this in the unit test.

I'll add it and see whether I can make that work :)

[Miauwkeru]

In C there is also the case that you can concatenate two defines if they have the same type. This doesn't work yet as it doesn't resolve yet. I think it might be better to put that functionality in a different pr if we want it.

def test_preprocessor_define_substitute_define(cs: cstruct) -> None:
    """Test whether we can concatinate defines with other strings."""
    c_def = """
    #define DATA1 "world"
    #define CONCAT "hello" \\
            DATA1
    """
    cs.load(c_def)

    assert cs.consts["CONCAT"] == "helloworld"