1/************************************************* 2* Perl-Compatible Regular Expressions * 3*************************************************/ 4 5/* PCRE is a library of functions to support regular expressions whose syntax 6and semantics are as close as possible to those of the Perl 5 language. 7 8 Written by Philip Hazel 9 Copyright (c) 1997-2009 University of Cambridge 10 11----------------------------------------------------------------------------- 12Redistribution and use in source and binary forms, with or without 13modification, 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 26THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 27AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 30LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36POSSIBILITY OF SUCH DAMAGE. 37----------------------------------------------------------------------------- 38*/ 39 40 41/* This module contains an internal function for validating UTF-8 character 42strings. */ 43 44 45#ifdef HAVE_CONFIG_H 46#include "config.h" 47#endif 48 49#include "pcre_internal.h" 50 51 52/************************************************* 53* Validate a UTF-8 string * 54*************************************************/ 55 56/* This function is called (optionally) at the start of compile or match, to 57validate that a supposed UTF-8 string is actually valid. The early check means 58that subsequent code can assume it is dealing with a valid string. The check 59can be turned off for maximum performance, but the consequences of supplying 60an invalid string are then undefined. 61 62Originally, this function checked according to RFC 2279, allowing for values in 63the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in 64the canonical format. Once somebody had pointed out RFC 3629 to me (it 65obsoletes 2279), additional restrictions were applied. The values are now 66limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the 67subrange 0xd000 to 0xdfff is excluded. 68 69Arguments: 70 string points to the string 71 length length of string, or -1 if the string is zero-terminated 72 73Returns: < 0 if the string is a valid UTF-8 string 74 >= 0 otherwise; the value is the offset of the bad byte 75*/ 76 77int 78_pcre_valid_utf8(USPTR string, int length) 79{ 80#ifdef SUPPORT_UTF8 81register USPTR p; 82 83if (length < 0) 84 { 85 for (p = string; *p != 0; p++); 86 length = p - string; 87 } 88 89for (p = string; length-- > 0; p++) 90 { 91 register int ab; 92 register int c = *p; 93 if (c < 128) continue; 94 if (c < 0xc0) return p - string; 95 ab = _pcre_utf8_table4[c & 0x3f]; /* Number of additional bytes */ 96 if (length < ab || ab > 3) return p - string; 97 length -= ab; 98 99 /* Check top bits in the second byte */ 100 if ((*(++p) & 0xc0) != 0x80) return p - string; 101 102 /* Check for overlong sequences for each different length, and for the 103 excluded range 0xd000 to 0xdfff. */ 104 105 switch (ab) 106 { 107 /* Check for xx00 000x (overlong sequence) */ 108 109 case 1: 110 if ((c & 0x3e) == 0) return p - string; 111 continue; /* We know there aren't any more bytes to check */ 112 113 /* Check for 1110 0000, xx0x xxxx (overlong sequence) or 114 1110 1101, 1010 xxxx (0xd000 - 0xdfff) */ 115 116 case 2: 117 if ((c == 0xe0 && (*p & 0x20) == 0) || 118 (c == 0xed && *p >= 0xa0)) 119 return p - string; 120 break; 121 122 /* Check for 1111 0000, xx00 xxxx (overlong sequence) or 123 greater than 0x0010ffff (f4 8f bf bf) */ 124 125 case 3: 126 if ((c == 0xf0 && (*p & 0x30) == 0) || 127 (c > 0xf4 ) || 128 (c == 0xf4 && *p > 0x8f)) 129 return p - string; 130 break; 131 132#if 0 133 /* These cases can no longer occur, as we restrict to a maximum of four 134 bytes nowadays. Leave the code here in case we ever want to add an option 135 for longer sequences. */ 136 137 /* Check for 1111 1000, xx00 0xxx */ 138 case 4: 139 if (c == 0xf8 && (*p & 0x38) == 0) return p - string; 140 break; 141 142 /* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */ 143 case 5: 144 if (c == 0xfe || c == 0xff || 145 (c == 0xfc && (*p & 0x3c) == 0)) return p - string; 146 break; 147#endif 148 149 } 150 151 /* Check for valid bytes after the 2nd, if any; all must start 10 */ 152 while (--ab > 0) 153 { 154 if ((*(++p) & 0xc0) != 0x80) return p - string; 155 } 156 } 157#else 158(void)(string); /* Keep picky compilers happy */ 159(void)(length); 160#endif 161 162return -1; 163} 164 165/* End of pcre_valid_utf8.c */ 166