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Annotation of embedaddon/pcre/pcre16_valid_utf16.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) 1997-2012 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 an internal function for validating UTF-16 character
                     42: strings. */
                     43: 
                     44: 
                     45: #ifdef HAVE_CONFIG_H
                     46: #include "config.h"
                     47: #endif
                     48: 
                     49: /* Generate code with 16 bit character support. */
                     50: #define COMPILE_PCRE16
                     51: 
                     52: #include "pcre_internal.h"
                     53: 
                     54: 
                     55: /*************************************************
                     56: *         Validate a UTF-16 string                *
                     57: *************************************************/
                     58: 
                     59: /* This function is called (optionally) at the start of compile or match, to
                     60: check that a supposed UTF-16 string is actually valid. The early check means
                     61: that subsequent code can assume it is dealing with a valid string. The check
                     62: can be turned off for maximum performance, but the consequences of supplying an
                     63: invalid string are then undefined.
                     64: 
                     65: From release 8.21 more information about the details of the error are passed
                     66: back in the returned value:
                     67: 
                     68: PCRE_UTF16_ERR0  No error
                     69: PCRE_UTF16_ERR1  Missing low surrogate at the end of the string
                     70: PCRE_UTF16_ERR2  Invalid low surrogate
                     71: PCRE_UTF16_ERR3  Isolated low surrogate
                     72: PCRE_UTF16_ERR4  Not allowed character
                     73: 
                     74: Arguments:
                     75:   string       points to the string
                     76:   length       length of string, or -1 if the string is zero-terminated
                     77:   errp         pointer to an error position offset variable
                     78: 
                     79: Returns:       = 0    if the string is a valid UTF-16 string
                     80:                > 0    otherwise, setting the offset of the bad character
                     81: */
                     82: 
                     83: int
                     84: PRIV(valid_utf)(PCRE_PUCHAR string, int length, int *erroroffset)
                     85: {
                     86: #ifdef SUPPORT_UTF
                     87: register PCRE_PUCHAR p;
                     88: register pcre_uchar c;
                     89: 
                     90: if (length < 0)
                     91:   {
                     92:   for (p = string; *p != 0; p++);
                     93:   length = p - string;
                     94:   }
                     95: 
                     96: for (p = string; length-- > 0; p++)
                     97:   {
                     98:   c = *p;
                     99: 
                    100:   if ((c & 0xf800) != 0xd800)
                    101:     {
                    102:     /* Normal UTF-16 code point. Neither high nor low surrogate. */
                    103: 
                    104:     /* This is probably a BOM from a different byte-order.
                    105:     Regardless, the string is rejected. */
                    106:     if (c == 0xfffe)
                    107:       {
                    108:       *erroroffset = p - string;
                    109:       return PCRE_UTF16_ERR4;
                    110:       }
                    111:     }
                    112:   else if ((c & 0x0400) == 0)
                    113:     {
                    114:     /* High surrogate. */
                    115: 
                    116:     /* Must be a followed by a low surrogate. */
                    117:     if (length == 0)
                    118:       {
                    119:       *erroroffset = p - string;
                    120:       return PCRE_UTF16_ERR1;
                    121:       }
                    122:     p++;
                    123:     length--;
                    124:     if ((*p & 0xfc00) != 0xdc00)
                    125:       {
                    126:       *erroroffset = p - string;
                    127:       return PCRE_UTF16_ERR2;
                    128:       }
                    129:     }
                    130:   else
                    131:     {
                    132:     /* Isolated low surrogate. Always an error. */
                    133:     *erroroffset = p - string;
                    134:     return PCRE_UTF16_ERR3;
                    135:     }
                    136:   }
                    137: 
                    138: #else  /* SUPPORT_UTF */
                    139: (void)(string);  /* Keep picky compilers happy */
                    140: (void)(length);
                    141: #endif /* SUPPORT_UTF */
                    142: 
                    143: return PCRE_UTF16_ERR0;   /* This indicates success */
                    144: }
                    145: 
                    146: /* End of pcre16_valid_utf16.c */