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ascii-boxes / boxes

Command line ASCII boxes unlimited!
https://boxes.thomasjensen.com/
GNU General Public License v3.0
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Fix crash in #103 #104

Closed sgn closed 2 years ago

sgn commented 2 years ago

See #103 and https://github.com/void-linux/void-packages/issues/39624

tsjensen commented 2 years ago

Thank you for providing us with a fix! 👍

Before I merge, I'd like to understand the change a little better, if that's OK with you. In the call to u32_move(), you changed the number of characters moved. It is calculated as input.lines[j].num_chars - input.lines[j].posmap[c] + 1, where num_chars is in characters, but posmap[c] is in bytes. How does that result in a valid number? Or is my assumption about num_chars incorrect?

sgn commented 2 years ago

Your assumption about num_chars is correct. It's counted by characters. However, posmap[c] is in characters, too. Quoting your code: https://github.com/ascii-boxes/boxes/blob/7de6854fd97e9fc256f1cf847cbc37c9f0f1cf1c/src/boxes.in.h#L146

tsjensen commented 2 years ago

Ah, right, I get it now. I literally wrote this in the previous millennium, so bear with me. 😊

posmap gives the position in mbtext for each visible character. All the invisible characters, like ANSI color codes, are ignored. The full posmap looks like this:

image

In this test case, we want to remove 3 spaces from the beginning of the string, which means that we must remove 55 characters, including lots of invisible ones. So, as you said from the start, we were moving too many characters.