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Diffstat (limited to 'erts/emulator/pcre/pcre_valid_utf8.c')
| -rw-r--r-- | erts/emulator/pcre/pcre_valid_utf8.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/erts/emulator/pcre/pcre_valid_utf8.c b/erts/emulator/pcre/pcre_valid_utf8.c new file mode 100644 index 0000000000..30af207ae3 --- /dev/null +++ b/erts/emulator/pcre/pcre_valid_utf8.c @@ -0,0 +1,163 @@ +/************************************************* +* Perl-Compatible Regular Expressions * +*************************************************/ + +/* PCRE is a library of functions to support regular expressions whose syntax +and semantics are as close as possible to those of the Perl 5 language. + + Written by Philip Hazel + Copyright (c) 1997-2008 University of Cambridge + +----------------------------------------------------------------------------- +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + * Redistributions of source code must retain the above copyright notice, + this list of conditions and the following disclaimer. + + * Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + + * Neither the name of the University of Cambridge nor the names of its + contributors may be used to endorse or promote products derived from + this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +POSSIBILITY OF SUCH DAMAGE. +----------------------------------------------------------------------------- +*/ + + +/* This module contains an internal function for validating UTF-8 character +strings. */ + +/* %ExternalCopyright% */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include "pcre_internal.h" + + +/************************************************* +* Validate a UTF-8 string * +*************************************************/ + +/* This function is called (optionally) at the start of compile or match, to +validate that a supposed UTF-8 string is actually valid. The early check means +that subsequent code can assume it is dealing with a valid string. The check +can be turned off for maximum performance, but the consequences of supplying +an invalid string are then undefined. + +Originally, this function checked according to RFC 2279, allowing for values in +the range 0 to 0x7fffffff, up to 6 bytes long, but ensuring that they were in +the canonical format. Once somebody had pointed out RFC 3629 to me (it +obsoletes 2279), additional restrictions were applied. The values are now +limited to be between 0 and 0x0010ffff, no more than 4 bytes long, and the +subrange 0xd000 to 0xdfff is excluded. + +Arguments: + string points to the string + length length of string, or -1 if the string is zero-terminated + +Returns: < 0 if the string is a valid UTF-8 string + >= 0 otherwise; the value is the offset of the bad byte +*/ + +int +_erts_pcre_valid_utf8(const uschar *string, int length) +{ +#ifdef SUPPORT_UTF8 +register const uschar *p; + +if (length < 0) + { + for (p = string; *p != 0; p++); + length = p - string; + } + +for (p = string; length-- > 0; p++) + { + register int ab; + register int c = *p; + if (c < 128) continue; + if (c < 0xc0) return p - string; + ab = _erts_pcre_utf8_table4[c & 0x3f]; /* Number of additional bytes */ + if (length < ab || ab > 3) return p - string; + length -= ab; + + /* Check top bits in the second byte */ + if ((*(++p) & 0xc0) != 0x80) return p - string; + + /* Check for overlong sequences for each different length, and for the + excluded range 0xd000 to 0xdfff. */ + + switch (ab) + { + /* Check for xx00 000x (overlong sequence) */ + + case 1: + if ((c & 0x3e) == 0) return p - string; + continue; /* We know there aren't any more bytes to check */ + + /* Check for 1110 0000, xx0x xxxx (overlong sequence) or + 1110 1101, 1010 xxxx (0xd000 - 0xdfff) */ + + case 2: + if ((c == 0xe0 && (*p & 0x20) == 0) || + (c == 0xed && *p >= 0xa0)) + return p - string; + break; + + /* Check for 1111 0000, xx00 xxxx (overlong sequence) or + greater than 0x0010ffff (f4 8f bf bf) */ + + case 3: + if ((c == 0xf0 && (*p & 0x30) == 0) || + (c > 0xf4 ) || + (c == 0xf4 && *p > 0x8f)) + return p - string; + break; + +#if 0 + /* These cases can no longer occur, as we restrict to a maximum of four + bytes nowadays. Leave the code here in case we ever want to add an option + for longer sequences. */ + + /* Check for 1111 1000, xx00 0xxx */ + case 4: + if (c == 0xf8 && (*p & 0x38) == 0) return p - string; + break; + + /* Check for leading 0xfe or 0xff, and then for 1111 1100, xx00 00xx */ + case 5: + if (c == 0xfe || c == 0xff || + (c == 0xfc && (*p & 0x3c) == 0)) return p - string; + break; +#endif + + } + + /* Check for valid bytes after the 2nd, if any; all must start 10 */ + while (--ab > 0) + { + if ((*(++p) & 0xc0) != 0x80) return p - string; + } + } +#endif + +return -1; +} + +/* End of pcre_valid_utf8.c */ |