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Annotation of embedaddon/php/ext/pcre/pcrelib/pcre_version.c, revision 1.1.1.1

1.1       misho       1: /*************************************************
                      2: *      Perl-Compatible Regular Expressions       *
                      3: *************************************************/
                      4: 
                      5: /* PCRE is a library of functions to support regular expressions whose syntax
                      6: and semantics are as close as possible to those of the Perl 5 language.
                      7: 
                      8:                        Written by Philip Hazel
                      9:            Copyright (c) 1997-2008 University of Cambridge
                     10: 
                     11: -----------------------------------------------------------------------------
                     12: Redistribution and use in source and binary forms, with or without
                     13: modification, are permitted provided that the following conditions are met:
                     14: 
                     15:     * Redistributions of source code must retain the above copyright notice,
                     16:       this list of conditions and the following disclaimer.
                     17: 
                     18:     * Redistributions in binary form must reproduce the above copyright
                     19:       notice, this list of conditions and the following disclaimer in the
                     20:       documentation and/or other materials provided with the distribution.
                     21: 
                     22:     * Neither the name of the University of Cambridge nor the names of its
                     23:       contributors may be used to endorse or promote products derived from
                     24:       this software without specific prior written permission.
                     25: 
                     26: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
                     27: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     28: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     29: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
                     30: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
                     31: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
                     32: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
                     33: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
                     34: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
                     35: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
                     36: POSSIBILITY OF SUCH DAMAGE.
                     37: -----------------------------------------------------------------------------
                     38: */
                     39: 
                     40: 
                     41: /* This module contains the external function pcre_version(), which returns a
                     42: string that identifies the PCRE version that is in use. */
                     43: 
                     44: 
                     45: #include "config.h"
                     46: 
                     47: #include "pcre_internal.h"
                     48: 
                     49: 
                     50: /*************************************************
                     51: *          Return version string                 *
                     52: *************************************************/
                     53: 
                     54: /* These macros are the standard way of turning unquoted text into C strings.
                     55: They allow macros like PCRE_MAJOR to be defined without quotes, which is
                     56: convenient for user programs that want to test its value. */
                     57: 
                     58: #define STRING(a)  # a
                     59: #define XSTRING(s) STRING(s)
                     60: 
                     61: /* A problem turned up with PCRE_PRERELEASE, which is defined empty for
                     62: production releases. Originally, it was used naively in this code:
                     63: 
                     64:   return XSTRING(PCRE_MAJOR)
                     65:          "." XSTRING(PCRE_MINOR)
                     66:              XSTRING(PCRE_PRERELEASE)
                     67:          " " XSTRING(PCRE_DATE);
                     68: 
                     69: However, when PCRE_PRERELEASE is empty, this leads to an attempted expansion of
                     70: STRING(). The C standard states: "If (before argument substitution) any
                     71: argument consists of no preprocessing tokens, the behavior is undefined." It
                     72: turns out the gcc treats this case as a single empty string - which is what we
                     73: really want - but Visual C grumbles about the lack of an argument for the
                     74: macro. Unfortunately, both are within their rights. To cope with both ways of
                     75: handling this, I had resort to some messy hackery that does a test at run time.
                     76: I could find no way of detecting that a macro is defined as an empty string at
                     77: pre-processor time. This hack uses a standard trick for avoiding calling
                     78: the STRING macro with an empty argument when doing the test. */
                     79: 
                     80: PCRE_EXP_DEFN const char * PCRE_CALL_CONVENTION
                     81: pcre_version(void)
                     82: {
                     83: return (XSTRING(Z PCRE_PRERELEASE)[1] == 0)?
                     84:   XSTRING(PCRE_MAJOR.PCRE_MINOR PCRE_DATE) :
                     85:   XSTRING(PCRE_MAJOR.PCRE_MINOR) XSTRING(PCRE_PRERELEASE PCRE_DATE);
                     86: }
                     87: 
                     88: /* End of pcre_version.c */