dvander@2762: /*************************************************
dvander@2762: *      Perl-Compatible Regular Expressions       *
dvander@2762: *************************************************/
dvander@2762: 
dvander@2762: /* PCRE is a library of functions to support regular expressions whose syntax
dvander@2762: and semantics are as close as possible to those of the Perl 5 language.
dvander@2762: 
dvander@2762:                        Written by Philip Hazel
dvander@2762:            Copyright (c) 1997-2009 University of Cambridge
dvander@2762: 
dvander@2762: -----------------------------------------------------------------------------
dvander@2762: Redistribution and use in source and binary forms, with or without
dvander@2762: modification, are permitted provided that the following conditions are met:
dvander@2762: 
dvander@2762:     * Redistributions of source code must retain the above copyright notice,
dvander@2762:       this list of conditions and the following disclaimer.
dvander@2762: 
dvander@2762:     * Redistributions in binary form must reproduce the above copyright
dvander@2762:       notice, this list of conditions and the following disclaimer in the
dvander@2762:       documentation and/or other materials provided with the distribution.
dvander@2762: 
dvander@2762:     * Neither the name of the University of Cambridge nor the names of its
dvander@2762:       contributors may be used to endorse or promote products derived from
dvander@2762:       this software without specific prior written permission.
dvander@2762: 
dvander@2762: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
dvander@2762: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
dvander@2762: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
dvander@2762: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
dvander@2762: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
dvander@2762: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
dvander@2762: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
dvander@2762: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
dvander@2762: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
dvander@2762: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
dvander@2762: POSSIBILITY OF SUCH DAMAGE.
dvander@2762: -----------------------------------------------------------------------------
dvander@2762: */
dvander@2762: 
dvander@2762: 
dvander@2762: /* This module contains an internal function for validating UTF-8 character
dvander@2762: strings. */
dvander@2762: 
dvander@2762: 
dvander@2762: #ifdef HAVE_CONFIG_H
dvander@2762: #include "config.h"
dvander@2762: #endif
dvander@2762: 
dvander@2762: #include "pcre_internal.h"
dvander@2762: 
dvander@2762: 
dvander@2762: /*************************************************
dvander@2762: *         Validate a UTF-8 string                *
dvander@2762: *************************************************/
dvander@2762: 
dvander@2762: /* This function is called (optionally) at the start of compile or match, to
dvander@2762: validate that a supposed UTF-8 string is actually valid. The early check means
dvander@2762: that subsequent code can assume it is dealing with a valid string. The check
dvander@2762: can be turned off for maximum performance, but the consequences of supplying
dvander@2762: an invalid string are then undefined.
dvander@2762: 
dvander@2762: Originally, this function checked according to RFC 2279, allowing for values in
dvander@2762: the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in
dvander@2762: the canonical format. Once somebody had pointed out RFC 3629 to me (it
dvander@2762: obsoletes 2279), additional restrictions were applied. The values are now
dvander@2762: limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the
dvander@2762: subrange 0xd000 to 0xdfff is excluded.
dvander@2762: 
dvander@2762: Arguments:
dvander@2762:   string       points to the string
dvander@2762:   length       length of string, or -1 if the string is zero-terminated
dvander@2762: 
dvander@2762: Returns:       < 0    if the string is a valid UTF-8 string
dvander@2762:                >= 0   otherwise; the value is the offset of the bad byte
dvander@2762: */
dvander@2762: 
dvander@2762: int
dvander@2762: _pcre_valid_utf8(USPTR string, int length)
dvander@2762: {
dvander@2762: #ifdef SUPPORT_UTF8
dvander@2762: register USPTR p;
dvander@2762: 
dvander@2762: if (length < 0)
dvander@2762:   {
dvander@2762:   for (p = string; *p != 0; p++);
dvander@2762:   length = p - string;
dvander@2762:   }
dvander@2762: 
dvander@2762: for (p = string; length-- > 0; p++)
dvander@2762:   {
dvander@2762:   register int ab;
dvander@2762:   register int c = *p;
dvander@2762:   if (c < 128) continue;
dvander@2762:   if (c < 0xc0) return p - string;
dvander@2762:   ab = _pcre_utf8_table4[c & 0x3f];     /* Number of additional bytes */
dvander@2762:   if (length < ab || ab > 3) return p - string;
dvander@2762:   length -= ab;
dvander@2762: 
dvander@2762:   /* Check top bits in the second byte */
dvander@2762:   if ((*(++p) & 0xc0) != 0x80) return p - string;
dvander@2762: 
dvander@2762:   /* Check for overlong sequences for each different length, and for the
dvander@2762:   excluded range 0xd000 to 0xdfff.  */
dvander@2762: 
dvander@2762:   switch (ab)
dvander@2762:     {
dvander@2762:     /* Check for xx00 000x (overlong sequence) */
dvander@2762: 
dvander@2762:     case 1:
dvander@2762:     if ((c & 0x3e) == 0) return p - string;
dvander@2762:     continue;   /* We know there aren't any more bytes to check */
dvander@2762: 
dvander@2762:     /* Check for 1110 0000, xx0x xxxx (overlong sequence) or
dvander@2762:                  1110 1101, 1010 xxxx (0xd000 - 0xdfff) */
dvander@2762: 
dvander@2762:     case 2:
dvander@2762:     if ((c == 0xe0 && (*p & 0x20) == 0) ||
dvander@2762:         (c == 0xed && *p >= 0xa0))
dvander@2762:       return p - string;
dvander@2762:     break;
dvander@2762: 
dvander@2762:     /* Check for 1111 0000, xx00 xxxx (overlong sequence) or
dvander@2762:        greater than 0x0010ffff (f4 8f bf bf) */
dvander@2762: 
dvander@2762:     case 3:
dvander@2762:     if ((c == 0xf0 && (*p & 0x30) == 0) ||
dvander@2762:         (c > 0xf4 ) ||
dvander@2762:         (c == 0xf4 && *p > 0x8f))
dvander@2762:       return p - string;
dvander@2762:     break;
dvander@2762: 
dvander@2762: #if 0
dvander@2762:     /* These cases can no longer occur, as we restrict to a maximum of four
dvander@2762:     bytes nowadays. Leave the code here in case we ever want to add an option
dvander@2762:     for longer sequences. */
dvander@2762: 
dvander@2762:     /* Check for 1111 1000, xx00 0xxx */
dvander@2762:     case 4:
dvander@2762:     if (c == 0xf8 && (*p & 0x38) == 0) return p - string;
dvander@2762:     break;
dvander@2762: 
dvander@2762:     /* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */
dvander@2762:     case 5:
dvander@2762:     if (c == 0xfe || c == 0xff ||
dvander@2762:        (c == 0xfc && (*p & 0x3c) == 0)) return p - string;
dvander@2762:     break;
dvander@2762: #endif
dvander@2762: 
dvander@2762:     }
dvander@2762: 
dvander@2762:   /* Check for valid bytes after the 2nd, if any; all must start 10 */
dvander@2762:   while (--ab > 0)
dvander@2762:     {
dvander@2762:     if ((*(++p) & 0xc0) != 0x80) return p - string;
dvander@2762:     }
dvander@2762:   }
dvander@2762: #else
dvander@2762: (void)(string);  /* Keep picky compilers happy */
dvander@2762: (void)(length);
dvander@2762: #endif
dvander@2762: 
dvander@2762: return -1;
dvander@2762: }
dvander@2762: 
dvander@2762: /* End of pcre_valid_utf8.c */