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lib/Crypt/SecretBuffer/Span.pm  view on Meta::CPAN

=head2 parse_asn1_der_length

  $len= $span->parse_asn1_der_length;

Parse the variable-length integer used by ASN.1 DER encoding for the length of an element.
On failure, returns C<undef> and sets L</last_error>.

=head2 consume_bom

  # On a buffer which may begin with a BOM:
  $span->consume_bom->cmp("\x{100}");

Look for an optional L<Byte-Order-Mark|https://en.wikipedia.org/wiki/Byte_order_mark> at the
start of the span, and if found, change the encoding and advance the span start to the next
character.

  First bytes       Encoding
  -----------       --------
  FE FF             UTF16BE
  FF FE             UTF16LE
  EF BB BF          UTF8

This returns the original Span object, with C<pos> and C<encoding> modified if a BOM was found.
This allows you to chain methods on a span object while conveniently processing the BOM.

This does not work if another encoding is being used to see those bytes, such as decoding BASE64.
A Span can have only one encoding, so if you need to decode BASE64 and then process a BOM, you
need to use L</copy> to create a new SecretBuffer of raw bytes, then decode the BOM.

=over

=item set_up_us_the_bom

Provided as an alias, for fun.

=back

=head2 starts_with

ppport.h  view on Meta::CPAN

BmPREVIOUS|5.003007||Viu
BmRARE|5.003007||Viu
BmUSEFUL|5.003007||Viu
BOL|5.003007||Viu
BOL_t8|5.035004||Viu
BOL_t8_p8|5.033003||Viu
BOL_t8_pb|5.033003||Viu
BOL_tb|5.035004||Viu
BOL_tb_p8|5.033003||Viu
BOL_tb_pb|5.033003||Viu
BOM_UTF8|5.025005|5.003007|p
BOM_UTF8_FIRST_BYTE|5.019004||Viu
BOM_UTF8_TAIL|5.019004||Viu
boolSV|5.004000|5.003007|p
boot_core_builtin|5.035007||Viu
boot_core_mro|5.009005||Viu
boot_core_PerlIO|5.007002||Viu
boot_core_UNIVERSAL|5.003007||Viu
BOUND|5.003007||Viu
BOUNDA|5.013009||Viu
BOUNDA_t8|5.035004||Viu
BOUNDA_t8_p8|5.033003||Viu
BOUNDA_t8_pb|5.033003||Viu

ppport.h  view on Meta::CPAN

#ifndef isUTF8_CHAR
#  define isUTF8_CHAR(s, e)              (                                            \
    (e) <= (s) || ! is_utf8_string(s, UTF8_SAFE_SKIP(s, e))                     \
    ? 0                                                                         \
    : UTF8SKIP(s))
#endif

#endif

#if 'A' == 65
#ifndef BOM_UTF8
#  define BOM_UTF8                       "\xEF\xBB\xBF"
#endif

#ifndef REPLACEMENT_CHARACTER_UTF8
#  define REPLACEMENT_CHARACTER_UTF8     "\xEF\xBF\xBD"
#endif

#elif '^' == 95
#ifndef BOM_UTF8
#  define BOM_UTF8                       "\xDD\x73\x66\x73"
#endif

#ifndef REPLACEMENT_CHARACTER_UTF8
#  define REPLACEMENT_CHARACTER_UTF8     "\xDD\x73\x73\x71"
#endif

#elif '^' == 176
#ifndef BOM_UTF8
#  define BOM_UTF8                       "\xDD\x72\x65\x72"
#endif

#ifndef REPLACEMENT_CHARACTER_UTF8
#  define REPLACEMENT_CHARACTER_UTF8     "\xDD\x72\x72\x70"
#endif

#else
#  error Unknown character set
#endif