diff options
| author | Nicholas Clark <nick@ccl4.org> | 2002-10-08 22:52:53 +0100 |
|---|---|---|
| committer | hv <hv@crypt.org> | 2002-10-12 15:31:06 +0000 |
| commit | 0258719bae4c02bba26598151f1f335a54f43190 (patch) | |
| tree | ef4daa815993b2559aa81888345fb50c8c2a14aa /pp_pack.c | |
| parent | b3c1f772f352b72296ce50a1ba2e7abcc581baaa (diff) | |
| download | perl-0258719bae4c02bba26598151f1f335a54f43190.tar.gz | |
Re: [perl #17772] pack "w" /* this cannot happen ;-) */ is fallacious
Message-ID: <20021008205253.GA283@Bagpuss.unfortu.net>
p4raw-id: //depot/perl@18010
Diffstat (limited to 'pp_pack.c')
| -rw-r--r-- | pp_pack.c | 18 |
1 files changed, 14 insertions, 4 deletions
@@ -2286,7 +2286,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg /* Copy string and check for compliance */ from = SvPV(fromstr, len); if ((norm = is_an_int(from, len)) == NULL) - Perl_croak(aTHX_ "can compress only unsigned integer"); + Perl_croak(aTHX_ "Can only compress unsigned integers"); New('w', result, len, char); in = result + len; @@ -2299,15 +2299,25 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg SvREFCNT_dec(norm); /* free norm */ } else if (SvNOKp(fromstr)) { - char buf[sizeof(NV) * 2]; /* 8/7 <= 2 */ + /* 10**NV_MAX_10_EXP is the largest power of 10 + so 10**(NV_MAX_10_EXP+1) is definately unrepresentable + given 10**(NV_MAX_10_EXP+1) == 128 ** x solve for x: + x = (NV_MAX_10_EXP+1) * log (10) / log (128) + And with that many bytes only Inf can overflow. + */ +#ifdef NV_MAX_10_EXP + char buf[1 + (int)((NV_MAX_10_EXP + 1) * 0.47456)]; +#else + char buf[1 + (int)((308 + 1) * 0.47456)]; +#endif char *in = buf + sizeof(buf); anv = Perl_floor(anv); do { NV next = Perl_floor(anv / 128); - *--in = (unsigned char)(anv - (next * 128)) | 0x80; if (in <= buf) /* this cannot happen ;-) */ Perl_croak(aTHX_ "Cannot compress integer"); + *--in = (unsigned char)(anv - (next * 128)) | 0x80; anv = next; } while (anv > 0); buf[sizeof(buf) - 1] &= 0x7f; /* clear continue bit */ @@ -2322,7 +2332,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg /* Copy string and check for compliance */ from = SvPV(fromstr, len); if ((norm = is_an_int(from, len)) == NULL) - Perl_croak(aTHX_ "can compress only unsigned integer"); + Perl_croak(aTHX_ "Can only compress unsigned integers"); New('w', result, len, char); in = result + len; |