| /* Private version of _pcre_valid_utf */ |
| |
| /************************************************* |
| * 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) 1997-2012 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. */ |
| |
| |
| /************************************************* |
| * Validate a UTF-8 string * |
| *************************************************/ |
| |
| /* This function is called (optionally) at the start of compile or match, to |
| check 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. However, the format of 5-byte and 6-byte |
| characters is still checked. |
| |
| */ |
| |
| static int |
| valid_utf8(const char *string, size_t length) // R change int->size_t |
| { |
| const char *p; |
| |
| for (p = string; length-- > 0; p++) { |
| int ab, c, d; |
| c = (unsigned char)*p; |
| if (c < 128) continue; /* ASCII character */ |
| if (c < 0xc0) return 1; /* Isolated 10xx xxxx byte */ |
| if (c >= 0xfe) return 1; /* Invalid 0xfe or 0xff bytes */ |
| |
| ab = utf8_table4[c & 0x3f]; /* Number of additional bytes */ |
| if (length < ab) return 1; |
| length -= ab; /* Length remaining */ |
| |
| /* Check top bits in the second byte */ |
| |
| if (((d = *(++p)) & 0xc0) != 0x80) return 1; |
| |
| /* For each length, check that the remaining bytes start with |
| the 0x80 bit set and not the 0x40 bit. Then check for an |
| overlong sequence, and for the excluded range 0xd800 to |
| 0xdfff. */ |
| |
| switch (ab) |
| { |
| /* 2-byte character. No further bytes to check for |
| 0x80. Check first byte for for xx00 000x (overlong |
| sequence). */ |
| case 1: |
| if ((c & 0x3e) == 0) return 1; |
| break; |
| |
| /* 3-byte character. Check third byte for 0x80. Then check |
| first 2 bytes for 1110 0000, xx0x xxxx (overlong |
| sequence) or 1110 1101, 1010 xxxx (0xd800 - 0xdfff) */ |
| case 2: |
| if ((*(++p) & 0xc0) != 0x80) return 1; /* Third byte */ |
| if (c == 0xe0 && (d & 0x20) == 0) return 1; |
| if (c == 0xed && d >= 0xa0) return 1; |
| break; |
| |
| /* 4-byte character. Check 3rd and 4th bytes for |
| 0x80. Then check first 2 bytes for for 1111 0000, xx00 |
| xxxx (overlong sequence), then check for a character |
| greater than 0x0010ffff (f4 8f bf bf) */ |
| case 3: |
| if ((*(++p) & 0xc0) != 0x80) return 1; /* Third byte */ |
| if ((*(++p) & 0xc0) != 0x80) return 1; /* Fourth byte */ |
| if (c == 0xf0 && (d & 0x30) == 0) return 1; |
| if (c > 0xf4 || (c == 0xf4 && d > 0x8f)) return 1; |
| break; |
| |
| /* 5-byte and 6-byte characters are not allowed by RFC |
| 3629, and will be rejected by the length test |
| below. However, we do the appropriate tests here so |
| that overlong sequences get diagnosed, and also in case |
| there is ever an option for handling these larger code |
| points. */ |
| |
| /* 5-byte character. Check 3rd, 4th, and 5th bytes for |
| 0x80. Then check for 1111 1000, xx00 0xxx */ |
| case 4: |
| if ((*(++p) & 0xc0) != 0x80) return 1; /* Third byte */ |
| if ((*(++p) & 0xc0) != 0x80) return 1; /* Fourth byte */ |
| if ((*(++p) & 0xc0) != 0x80) return 1; /* Fifth byte */ |
| if (c == 0xf8 && (d & 0x38) == 0) return 1; |
| break; |
| |
| /* 6-byte character. Check 3rd-6th bytes for 0x80. Then |
| check for 1111 1100, xx00 00xx. */ |
| case 5: |
| if ((*(++p) & 0xc0) != 0x80) return 1; /* Third byte */ |
| if ((*(++p) & 0xc0) != 0x80) return 1; /* Fourth byte */ |
| if ((*(++p) & 0xc0) != 0x80) return 1; /* Fifth byte */ |
| if ((*(++p) & 0xc0) != 0x80) return 1; /* Sixth byte */ |
| if (c == 0xfc && (d & 0x3c) == 0) return 1; |
| break; |
| } |
| |
| /* Character is valid under RFC 2279, but 4-byte and 5-byte |
| characters are excluded by RFC 3629. The pointer p is |
| currently at the last byte of the character. */ |
| if (ab > 3) return 1; |
| } |
| |
| return 0; |
| } |