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131 lines
4.4 KiB
C
131 lines
4.4 KiB
C
/*************************************************
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* Perl-Compatible Regular Expressions *
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*************************************************/
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/* PCRE is a library of functions to support regular expressions whose syntax
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and semantics are as close as possible to those of the Perl 5 language.
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Written by Philip Hazel
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Copyright (c) 1997-2005 University of Cambridge
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-----------------------------------------------------------------------------
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the University of Cambridge nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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-----------------------------------------------------------------------------
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*/
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/* This module contains an internal function for validating UTF-8 character
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strings. */
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#include "pcre_internal.h"
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/*************************************************
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* Validate a UTF-8 string *
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*************************************************/
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/* This function is called (optionally) at the start of compile or match, to
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validate that a supposed UTF-8 string is actually valid. The early check means
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that subsequent code can assume it is dealing with a valid string. The check
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can be turned off for maximum performance, but the consequences of supplying
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an invalid string are then undefined.
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Arguments:
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string points to the string
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length length of string, or -1 if the string is zero-terminated
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Returns: < 0 if the string is a valid UTF-8 string
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>= 0 otherwise; the value is the offset of the bad byte
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*/
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EXPORT int
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_pcre_valid_utf8(const uschar *string, int length)
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{
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register const uschar *p;
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if (length < 0)
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{
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for (p = string; *p != 0; p++);
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length = p - string;
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}
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for (p = string; length-- > 0; p++)
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{
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register int ab;
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register int c = *p;
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if (c < 128) continue;
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if ((c & 0xc0) != 0xc0) return p - string;
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ab = _pcre_utf8_table4[c & 0x3f]; /* Number of additional bytes */
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if (length < ab) return p - string;
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length -= ab;
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/* Check top bits in the second byte */
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if ((*(++p) & 0xc0) != 0x80) return p - string;
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/* Check for overlong sequences for each different length */
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switch (ab)
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{
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/* Check for xx00 000x */
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case 1:
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if ((c & 0x3e) == 0) return p - string;
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continue; /* We know there aren't any more bytes to check */
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/* Check for 1110 0000, xx0x xxxx */
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case 2:
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if (c == 0xe0 && (*p & 0x20) == 0) return p - string;
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break;
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/* Check for 1111 0000, xx00 xxxx */
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case 3:
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if (c == 0xf0 && (*p & 0x30) == 0) return p - string;
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break;
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/* Check for 1111 1000, xx00 0xxx */
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case 4:
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if (c == 0xf8 && (*p & 0x38) == 0) return p - string;
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break;
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/* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */
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case 5:
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if (c == 0xfe || c == 0xff ||
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(c == 0xfc && (*p & 0x3c) == 0)) return p - string;
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break;
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}
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/* Check for valid bytes after the 2nd, if any; all must start 10 */
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while (--ab > 0)
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{
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if ((*(++p) & 0xc0) != 0x80) return p - string;
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}
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}
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return -1;
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}
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/* End of pcre_valid_utf8.c */
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