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Annotation of embedaddon/pcre/pcre16_valid_utf16.c, revision 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 */