Re: [PATCH v6] diff-delta: use safe integer arithmetic

From: Pablo Sabater <pabloosabaterr@gmail.com>
Date: Oct 27, 2026, 11:32 UTC
Message-ID: <DMFL6539NDIW.2LN0YXSJH5VT9@gmail.com>
In-Reply-To: <CABh_KWhac74wQY3sTAFp7f_9CKKAmBWcE9wir4_1i7iZqsq8fw@mail.gmail.com>

On Tue Oct 27, 2026 at 11:01 AM WET, Srujith Poojary wrote:

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> On Tue, Oct 27, 2026 at 4:03 PM Pablo Sabater <pabloosabaterr@gmail.com> wrote:
>>
>> On Tue Oct 27, 2026 at 4:51 AM WET, Srujith A Poojary via GitGitGadget wrote:
>> > From: Srujith A Poojary <poojarysrujith@gmail.com>
>> >
>> [snip]
>> >
>> > For the unpacked index allocation:
>> > - sizeof(struct unpacked_index_entry) is 12 bytes on 32-bit systems,
>> >   which may be padded to 16 bytes depending on compiler alignment rules.
>>
>>         l 117-125 'diff-delta.c'
>>
>>         struct index_entry {
>>                 const unsigned char *ptr;
>>                 unsigned int val;
>>         };
>>
>>         struct unpacked_index_entry {
>>                 struct index_entry entry;
>>                 struct unpacked_index_entry *next;
>>         };
>>
>> On 32 bit systems we have 4 bytes ptr + 4 bytes uint + 4 bytes ptr. I
>> don't see how it could be padded to 16.
>>

[snip]

> Hi Pablo,
>
> Thank you for reviewing the code and catching that! You are completely
> right—on 32-bit systems, the fields sum up cleanly to 16 bytes without

12 bytes, not 16.

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> needing extra alignment padding.
> I have updated the commit message in v7 to reflect your exact
> breakdown. Thanks again for the thorough check!
>
> Best regards,
> Srujith

Regards, Pablo.