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pcre_maketables.c
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00001 /*************************************************
00002 *      Perl-Compatible Regular Expressions       *
00003 *************************************************/
00004 
00005 /* PCRE is a library of functions to support regular expressions whose syntax
00006 and semantics are as close as possible to those of the Perl 5 language.
00007 
00008                        Written by Philip Hazel
00009            Copyright (c) 1997-2008 University of Cambridge
00010 
00011 -----------------------------------------------------------------------------
00012 Redistribution and use in source and binary forms, with or without
00013 modification, are permitted provided that the following conditions are met:
00014 
00015     * Redistributions of source code must retain the above copyright notice,
00016       this list of conditions and the following disclaimer.
00017 
00018     * Redistributions in binary form must reproduce the above copyright
00019       notice, this list of conditions and the following disclaimer in the
00020       documentation and/or other materials provided with the distribution.
00021 
00022     * Neither the name of the University of Cambridge nor the names of its
00023       contributors may be used to endorse or promote products derived from
00024       this software without specific prior written permission.
00025 
00026 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
00027 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00028 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00029 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
00030 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
00031 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
00032 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00033 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00034 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
00035 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00036 POSSIBILITY OF SUCH DAMAGE.
00037 -----------------------------------------------------------------------------
00038 */
00039 
00040 
00041 /* This module contains the external function pcre_maketables(), which builds
00042 character tables for PCRE in the current locale. The file is compiled on its
00043 own as part of the PCRE library. However, it is also included in the
00044 compilation of dftables.c, in which case the macro DFTABLES is defined. */
00045 
00046 
00047 #ifndef DFTABLES
00048 #  include "config.h"
00049 #  include "pcre_internal.h"
00050 #endif
00051 
00052 
00053 /*************************************************
00054 *           Create PCRE character tables         *
00055 *************************************************/
00056 
00057 /* This function builds a set of character tables for use by PCRE and returns
00058 a pointer to them. They are build using the ctype functions, and consequently
00059 their contents will depend upon the current locale setting. When compiled as
00060 part of the library, the store is obtained via pcre_malloc(), but when compiled
00061 inside dftables, use malloc().
00062 
00063 Arguments:   none
00064 Returns:     pointer to the contiguous block of data
00065 */
00066 
00067 const unsigned char *
00068 pcre_maketables(void)
00069 {
00070 unsigned char *yield, *p;
00071 int i;
00072 
00073 #ifndef DFTABLES
00074 yield = (unsigned char*)(pcre_malloc)(tables_length);
00075 #else
00076 yield = (unsigned char*)malloc(tables_length);
00077 #endif
00078 
00079 if (yield == NULL) return NULL;
00080 p = yield;
00081 
00082 /* First comes the lower casing table */
00083 
00084 for (i = 0; i < 256; i++) *p++ = tolower(i);
00085 
00086 /* Next the case-flipping table */
00087 
00088 for (i = 0; i < 256; i++) *p++ = islower(i)? toupper(i) : tolower(i);
00089 
00090 /* Then the character class tables. Don't try to be clever and save effort on
00091 exclusive ones - in some locales things may be different. Note that the table
00092 for "space" includes everything "isspace" gives, including VT in the default
00093 locale. This makes it work for the POSIX class [:space:]. Note also that it is
00094 possible for a character to be alnum or alpha without being lower or upper,
00095 such as "male and female ordinals" (\xAA and \xBA) in the fr_FR locale (at
00096 least under Debian Linux's locales as of 12/2005). So we must test for alnum
00097 specially. */
00098 
00099 memset(p, 0, cbit_length);
00100 for (i = 0; i < 256; i++)
00101   {
00102   if (isdigit(i)) p[cbit_digit  + i/8] |= 1 << (i&7);
00103   if (isupper(i)) p[cbit_upper  + i/8] |= 1 << (i&7);
00104   if (islower(i)) p[cbit_lower  + i/8] |= 1 << (i&7);
00105   if (isalnum(i)) p[cbit_word   + i/8] |= 1 << (i&7);
00106   if (i == '_')   p[cbit_word   + i/8] |= 1 << (i&7);
00107   if (isspace(i)) p[cbit_space  + i/8] |= 1 << (i&7);
00108   if (isxdigit(i))p[cbit_xdigit + i/8] |= 1 << (i&7);
00109   if (isgraph(i)) p[cbit_graph  + i/8] |= 1 << (i&7);
00110   if (isprint(i)) p[cbit_print  + i/8] |= 1 << (i&7);
00111   if (ispunct(i)) p[cbit_punct  + i/8] |= 1 << (i&7);
00112   if (iscntrl(i)) p[cbit_cntrl  + i/8] |= 1 << (i&7);
00113   }
00114 p += cbit_length;
00115 
00116 /* Finally, the character type table. In this, we exclude VT from the white
00117 space chars, because Perl doesn't recognize it as such for \s and for comments
00118 within regexes. */
00119 
00120 for (i = 0; i < 256; i++)
00121   {
00122   int x = 0;
00123   if (i != 0x0b && isspace(i)) x += ctype_space;
00124   if (isalpha(i)) x += ctype_letter;
00125   if (isdigit(i)) x += ctype_digit;
00126   if (isxdigit(i)) x += ctype_xdigit;
00127   if (isalnum(i) || i == '_') x += ctype_word;
00128 
00129   /* Note: strchr includes the terminating zero in the characters it considers.
00130   In this instance, that is ok because we want binary zero to be flagged as a
00131   meta-character, which in this sense is any character that terminates a run
00132   of data characters. */
00133 
00134   if (strchr("\\*+?{^.$|()[", i) != 0) x += ctype_meta;
00135   *p++ = x;
00136   }
00137 
00138 return yield;
00139 }
00140 
00141 /* End of pcre_maketables.c */