Annotation of win32/pcre/pcre_valid_utf8.c, revision 1.1
1.1 ! misha 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) 1997-2008 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-8 character
! 42: strings. */
! 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
! 57: validate that a supposed UTF-8 string is actually valid. The early check means
! 58: that subsequent code can assume it is dealing with a valid string. The check
! 59: can be turned off for maximum performance, but the consequences of supplying
! 60: an invalid string are then undefined.
! 61:
! 62: Originally, this function checked according to RFC 2279, allowing for values in
! 63: the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in
! 64: the canonical format. Once somebody had pointed out RFC 3629 to me (it
! 65: obsoletes 2279), additional restrictions were applied. The values are now
! 66: limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the
! 67: subrange 0xd000 to 0xdfff is excluded.
! 68:
! 69: Arguments:
! 70: string points to the string
! 71: length length of string, or -1 if the string is zero-terminated
! 72:
! 73: Returns: < 0 if the string is a valid UTF-8 string
! 74: >= 0 otherwise; the value is the offset of the bad byte
! 75: */
! 76:
! 77: int
! 78: _pcre_valid_utf8(const uschar *string, int length)
! 79: {
! 80: #ifdef SUPPORT_UTF8
! 81: register const uschar *p;
! 82:
! 83: if (length < 0)
! 84: {
! 85: for (p = string; *p != 0; p++);
! 86: length = p - string;
! 87: }
! 88:
! 89: for (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: #endif
! 158:
! 159: return -1;
! 160: }
! 161:
! 162: /* End of pcre_valid_utf8.c */
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