Re: [PATCHES] Fix memcmp() with different sizes.

[Kurt Roeckx]

On Mon, Feb 02, 2004 at 09:27:46PM -0500, Tom Lane wrote:
 Kurt Roeckx [EMAIL PROTECTED] writes:
  -   if (memcmp(re_array[i].cre_pat, text_re, text_re_len) == 0 
  +   if (VARSIZE(re_array[i].cre_pat) == text_re_len 
  +   memcmp(re_array[i].cre_pat, text_re, text_re_len) == 0 
 
 This is not actually broken.  The first four bytes of what memcmp is
 comparing are the length, and so it'll fall out immediately anyway if
 the lengths differ.

That assumes the memcmp starts from the first char and not from
the last.  If it starts from the last you have undefined
behaviour.


Kurt


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Re: [PATCHES] Fix memcmp() with different sizes.

[Tom Lane]

Kurt Roeckx [EMAIL PROTECTED] writes:
 - if (memcmp(re_array[i].cre_pat, text_re, text_re_len) == 0 
 + if (VARSIZE(re_array[i].cre_pat) == text_re_len 
 + memcmp(re_array[i].cre_pat, text_re, text_re_len) == 0 

This is not actually broken.  The first four bytes of what memcmp is
comparing are the length, and so it'll fall out immediately anyway if
the lengths differ.

regards, tom lane

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