ICU-22251 Move sprintf to snprintf.

[FrankYFTang]

Checklist

• Required: Issue filed: https://unicode-org.atlassian.net/browse/ICU-22251
• Required: The PR title must be prefixed with a JIRA Issue number.
• Required: The PR description must include the link to the Jira Issue, for example by completing the URL in the first checklist item
• Required: Each commit message must be prefixed with a JIRA Issue number.
• Issue accepted (done by Technical Committee after discussion)
• Tests included, if applicable
• API docs and/or User Guide docs changed or added, if applicable

[richgillam]

This all looks good. Looks mechanical, except for the calculation of the buffer size. I didn't review all of those carefully, but the ones I did all looked right.

[richgillam]

New stuff looks good too.

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[roubert]

I really don't think that you should be hardcoding any of these numbers, that wouldn't get us any real improved memory safety, it would just move the places where things could go wrong.

Instead, existing code like this:

char tmp[16];
sprintf(tmp, "%d", value);

Should be replaced with new code like this:

char tmp[16];
snprintf(tmp, sizeof tmp, "%d", value);

Or, when that's not possible, some kind of logic / argument passing that ensures that the value used is ultimately calculated by the compiler from the actual buffer size.

[FrankYFTang]

Should be replaced with new code like this:

char tmp[16];
snprintf(tmp, sizeof tmp, "%d", value);

DONE

[richgillam]

Looks good, and I think Fredrik's recommendation is a good one and makes the code more readable and bulletproof. But I think you missed a couple spots...

[richgillam]

Is there a reason why you didn't use sizeof here?

[FrankYFTang]

somehow I missed this

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[FrankYFTang]

PTAL

[richgillam]

It all looks fine. Cut and print.

[FrankYFTang]

I really don't think that you should be hardcoding any of these numbers, that wouldn't get us any real improved memory safety, it would just move the places where things could go wrong.

Instead, existing code like this:

char tmp[16];
sprintf(tmp, "%d", value);

Should be replaced with new code like this:

char tmp[16];
snprintf(tmp, sizeof tmp, "%d", value);

Or, when that's not possible, some kind of logic / argument passing that ensures that the value used is ultimately calculated by the compiler from the actual buffer size.

done

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