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| author | Father Chrysostomos <sprout@cpan.org> | 2013-07-23 13:15:34 -0700 |
|---|---|---|
| committer | Father Chrysostomos <sprout@cpan.org> | 2013-08-25 12:22:40 -0700 |
| commit | 25fdce4a165b6305e760d4c8d94404ce055657a0 (patch) | |
| tree | 7c3aa76b83b1518991bf23909ee072c55de29138 /mg.h | |
| parent | 428ccf1e2d78d72b07c5e959e967569a82ce07ba (diff) | |
| download | perl-25fdce4a165b6305e760d4c8d94404ce055657a0.tar.gz | |
Stop pos() from being confused by changing utf8ness
The value of pos() is stored as a byte offset. If it is stored on a
tied variable or a reference (or glob), then the stringification could
change, resulting in pos() now pointing to a different character off-
set or pointing to the middle of a character:
$ ./perl -Ilib -le '$x = bless [], chr 256; pos $x=1; bless $x, a; print pos $x'
2
$ ./perl -Ilib -le '$x = bless [], chr 256; pos $x=1; bless $x, "\x{1000}"; print pos $x'
Malformed UTF-8 character (unexpected end of string) in match position at -e line 1.
0
So pos() should be stored as a character offset.
The regular expression engine expects byte offsets always, so allow it
to store bytes when possible (a pure non-magical string) but use char-
acters otherwise.
This does result in more complexity than I should like, but the alter-
native (always storing a character offset) would slow down regular
expressions, which is a big no-no.
Diffstat (limited to 'mg.h')
| -rw-r--r-- | mg.h | 14 |
1 files changed, 14 insertions, 0 deletions
@@ -38,6 +38,7 @@ struct magic { #define MGf_COPY 8 /* has an svt_copy MGVTBL entry */ #define MGf_DUP 0x10 /* has an svt_dup MGVTBL entry */ #define MGf_LOCAL 0x20 /* has an svt_local MGVTBL entry */ +#define MGf_BYTES 0x40 /* PERL_MAGIC_regex_global only */ #define MgTAINTEDDIR(mg) (mg->mg_flags & MGf_TAINTEDDIR) #define MgTAINTEDDIR_on(mg) (mg->mg_flags |= MGf_TAINTEDDIR) @@ -57,6 +58,19 @@ struct magic { #define SvTIED_obj(sv,mg) \ ((mg)->mg_obj ? (mg)->mg_obj : sv_2mortal(newRV(sv))) +#if defined(PERL_CORE) || defined(PERL_EXT) +# define MgBYTEPOS(mg,sv,pv,len) S_MgBYTEPOS(aTHX_ mg,sv,pv,len) +/* assumes get-magic and stringification have already occurred */ +# define MgBYTEPOS_set(mg,sv,pv,off) ( \ + assert_((mg)->mg_type == PERL_MAGIC_regex_global) \ + SvPOK(sv) && !SvGMAGICAL(sv) \ + ? (mg)->mg_len = (off), (mg)->mg_flags |= MGf_BYTES \ + : ((mg)->mg_len = DO_UTF8(sv) \ + ? utf8_length((U8 *)(pv), (U8 *)(pv)+(off)) \ + : (off), \ + (mg)->mg_flags &= ~MGf_BYTES)) +#endif + #define whichsig(pv) whichsig_pv(pv) /* |