pcre2/src/pcre2_maketables.c

/*************************************************
*      Perl-Compatible Regular Expressions       *
*************************************************/

/* PCRE is a library of functions to support regular expressions whose syntax
and semantics are as close as possible to those of the Perl 5 language.

                       Written by Philip Hazel
     Original API code Copyright (c) 1997-2012 University of Cambridge
          New API code Copyright (c) 2016-2019 University of Cambridge

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*/


/* This module contains the external function pcre2_maketables(), which builds
character tables for PCRE2 in the current locale. The file is compiled on its
own as part of the PCRE2 library. However, it is also included in the
compilation of dftables.c, in which case the macro DFTABLES is defined. */

#ifndef DFTABLES
#  ifdef HAVE_CONFIG_H
#  include "config.h"
#  endif
#  include "pcre2_internal.h"
#endif



/*************************************************
*           Create PCRE2 character tables        *
*************************************************/

/* This function builds a set of character tables for use by PCRE2 and returns
a pointer to them. They are build using the ctype functions, and consequently
their contents will depend upon the current locale setting. When compiled as
part of the library, the store is obtained via a general context malloc, if
supplied, but when DFTABLES is defined (when compiling the dftables auxiliary
program) malloc() is used, and the function has a different name so as not to
clash with the prototype in pcre2.h.

Arguments:   none when DFTABLES is defined
             else a PCRE2 general context or NULL
Returns:     pointer to the contiguous block of data
*/

#ifdef DFTABLES  /* Included in freestanding dftables.c program */
static const uint8_t *maketables(void)
{
uint8_t *yield = (uint8_t *)malloc(tables_length);

#else  /* Not DFTABLES, compiling the library */
PCRE2_EXP_DEFN const uint8_t * PCRE2_CALL_CONVENTION
pcre2_maketables(pcre2_general_context *gcontext)
{
uint8_t *yield = (uint8_t *)((gcontext != NULL)?
  gcontext->memctl.malloc(tables_length, gcontext->memctl.memory_data) :
  malloc(tables_length));
#endif  /* DFTABLES */

int i;
uint8_t *p;

if (yield == NULL) return NULL;
p = yield;

/* First comes the lower casing table */

for (i = 0; i < 256; i++) *p++ = tolower(i);

/* Next the case-flipping table */

for (i = 0; i < 256; i++) *p++ = islower(i)? toupper(i) : tolower(i);

/* Then the character class tables. Don't try to be clever and save effort on
exclusive ones - in some locales things may be different.

Note that the table for "space" includes everything "isspace" gives, including
VT in the default locale. This makes it work for the POSIX class [:space:].
From release 8.34 is is also correct for Perl space, because Perl added VT at
release 5.18.

Note also that it is possible for a character to be alnum or alpha without
being lower or upper, such as "male and female ordinals" (\xAA and \xBA) in the
fr_FR locale (at least under Debian Linux's locales as of 12/2005). So we must
test for alnum specially. */

memset(p, 0, cbit_length);
for (i = 0; i < 256; i++)
  {
  if (isdigit(i)) p[cbit_digit  + i/8] |= 1u << (i&7);
  if (isupper(i)) p[cbit_upper  + i/8] |= 1u << (i&7);
  if (islower(i)) p[cbit_lower  + i/8] |= 1u << (i&7);
  if (isalnum(i)) p[cbit_word   + i/8] |= 1u << (i&7);
  if (i == '_')   p[cbit_word   + i/8] |= 1u << (i&7);
  if (isspace(i)) p[cbit_space  + i/8] |= 1u << (i&7);
  if (isxdigit(i))p[cbit_xdigit + i/8] |= 1u << (i&7);
  if (isgraph(i)) p[cbit_graph  + i/8] |= 1u << (i&7);
  if (isprint(i)) p[cbit_print  + i/8] |= 1u << (i&7);
  if (ispunct(i)) p[cbit_punct  + i/8] |= 1u << (i&7);
  if (iscntrl(i)) p[cbit_cntrl  + i/8] |= 1u << (i&7);
  }
p += cbit_length;

/* Finally, the character type table. In this, we used to exclude VT from the
white space chars, because Perl didn't recognize it as such for \s and for
comments within regexes. However, Perl changed at release 5.18, so PCRE changed
at release 8.34. */

for (i = 0; i < 256; i++)
  {
  int x = 0;
  if (isspace(i)) x += ctype_space;
  if (isalpha(i)) x += ctype_letter;
  if (islower(i)) x += ctype_lcletter;
  if (isdigit(i)) x += ctype_digit;
  if (isalnum(i) || i == '_') x += ctype_word;
  *p++ = x;
  }

return yield;
}

/* End of pcre2_maketables.c */