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Diffstat (limited to 'pcre/pcre_valid_utf8.c')
| -rw-r--r-- | pcre/pcre_valid_utf8.c | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/pcre/pcre_valid_utf8.c b/pcre/pcre_valid_utf8.c new file mode 100644 index 0000000..3b0f646 --- /dev/null +++ b/pcre/pcre_valid_utf8.c @@ -0,0 +1,301 @@ +/************************************************* +* 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) 1997-2013 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. */ + + +#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 +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. + +From release 8.13 more information about the details of the error are passed +back in the returned value: + +PCRE_UTF8_ERR0 No error +PCRE_UTF8_ERR1 Missing 1 byte at the end of the string +PCRE_UTF8_ERR2 Missing 2 bytes at the end of the string +PCRE_UTF8_ERR3 Missing 3 bytes at the end of the string +PCRE_UTF8_ERR4 Missing 4 bytes at the end of the string +PCRE_UTF8_ERR5 Missing 5 bytes at the end of the string +PCRE_UTF8_ERR6 2nd-byte's two top bits are not 0x80 +PCRE_UTF8_ERR7 3rd-byte's two top bits are not 0x80 +PCRE_UTF8_ERR8 4th-byte's two top bits are not 0x80 +PCRE_UTF8_ERR9 5th-byte's two top bits are not 0x80 +PCRE_UTF8_ERR10 6th-byte's two top bits are not 0x80 +PCRE_UTF8_ERR11 5-byte character is not permitted by RFC 3629 +PCRE_UTF8_ERR12 6-byte character is not permitted by RFC 3629 +PCRE_UTF8_ERR13 4-byte character with value > 0x10ffff is not permitted +PCRE_UTF8_ERR14 3-byte character with value 0xd000-0xdfff is not permitted +PCRE_UTF8_ERR15 Overlong 2-byte sequence +PCRE_UTF8_ERR16 Overlong 3-byte sequence +PCRE_UTF8_ERR17 Overlong 4-byte sequence +PCRE_UTF8_ERR18 Overlong 5-byte sequence (won't ever occur) +PCRE_UTF8_ERR19 Overlong 6-byte sequence (won't ever occur) +PCRE_UTF8_ERR20 Isolated 0x80 byte (not within UTF-8 character) +PCRE_UTF8_ERR21 Byte with the illegal value 0xfe or 0xff +PCRE_UTF8_ERR22 Unused (was non-character) + +Arguments: + string points to the string + length length of string, or -1 if the string is zero-terminated + errp pointer to an error position offset variable + +Returns: = 0 if the string is a valid UTF-8 string + > 0 otherwise, setting the offset of the bad character +*/ + +int +PRIV(valid_utf)(PCRE_PUCHAR string, int length, int *erroroffset) +{ +#ifdef SUPPORT_UTF +register PCRE_PUCHAR p; + +if (length < 0) + { + for (p = string; *p != 0; p++); + length = (int)(p - string); + } + +for (p = string; length-- > 0; p++) + { + register pcre_uchar ab, c, d; + + c = *p; + if (c < 128) continue; /* ASCII character */ + + if (c < 0xc0) /* Isolated 10xx xxxx byte */ + { + *erroroffset = (int)(p - string); + return PCRE_UTF8_ERR20; + } + + if (c >= 0xfe) /* Invalid 0xfe or 0xff bytes */ + { + *erroroffset = (int)(p - string); + return PCRE_UTF8_ERR21; + } + + ab = PRIV(utf8_table4)[c & 0x3f]; /* Number of additional bytes */ + if (length < ab) + { + *erroroffset = (int)(p - string); /* Missing bytes */ + return ab - length; /* Codes ERR1 to ERR5 */ + } + length -= ab; /* Length remaining */ + + /* Check top bits in the second byte */ + + if (((d = *(++p)) & 0xc0) != 0x80) + { + *erroroffset = (int)(p - string) - 1; + return PCRE_UTF8_ERR6; + } + + /* 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) + { + *erroroffset = (int)(p - string) - 1; + return PCRE_UTF8_ERR15; + } + 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) /* Third byte */ + { + *erroroffset = (int)(p - string) - 2; + return PCRE_UTF8_ERR7; + } + if (c == 0xe0 && (d & 0x20) == 0) + { + *erroroffset = (int)(p - string) - 2; + return PCRE_UTF8_ERR16; + } + if (c == 0xed && d >= 0xa0) + { + *erroroffset = (int)(p - string) - 2; + return PCRE_UTF8_ERR14; + } + 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) /* Third byte */ + { + *erroroffset = (int)(p - string) - 2; + return PCRE_UTF8_ERR7; + } + if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */ + { + *erroroffset = (int)(p - string) - 3; + return PCRE_UTF8_ERR8; + } + if (c == 0xf0 && (d & 0x30) == 0) + { + *erroroffset = (int)(p - string) - 3; + return PCRE_UTF8_ERR17; + } + if (c > 0xf4 || (c == 0xf4 && d > 0x8f)) + { + *erroroffset = (int)(p - string) - 3; + return PCRE_UTF8_ERR13; + } + 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) /* Third byte */ + { + *erroroffset = (int)(p - string) - 2; + return PCRE_UTF8_ERR7; + } + if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */ + { + *erroroffset = (int)(p - string) - 3; + return PCRE_UTF8_ERR8; + } + if ((*(++p) & 0xc0) != 0x80) /* Fifth byte */ + { + *erroroffset = (int)(p - string) - 4; + return PCRE_UTF8_ERR9; + } + if (c == 0xf8 && (d & 0x38) == 0) + { + *erroroffset = (int)(p - string) - 4; + return PCRE_UTF8_ERR18; + } + break; + + /* 6-byte character. Check 3rd-6th bytes for 0x80. Then check for + 1111 1100, xx00 00xx. */ + + case 5: + if ((*(++p) & 0xc0) != 0x80) /* Third byte */ + { + *erroroffset = (int)(p - string) - 2; + return PCRE_UTF8_ERR7; + } + if ((*(++p) & 0xc0) != 0x80) /* Fourth byte */ + { + *erroroffset = (int)(p - string) - 3; + return PCRE_UTF8_ERR8; + } + if ((*(++p) & 0xc0) != 0x80) /* Fifth byte */ + { + *erroroffset = (int)(p - string) - 4; + return PCRE_UTF8_ERR9; + } + if ((*(++p) & 0xc0) != 0x80) /* Sixth byte */ + { + *erroroffset = (int)(p - string) - 5; + return PCRE_UTF8_ERR10; + } + if (c == 0xfc && (d & 0x3c) == 0) + { + *erroroffset = (int)(p - string) - 5; + return PCRE_UTF8_ERR19; + } + 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) + { + *erroroffset = (int)(p - string) - ab; + return (ab == 4)? PCRE_UTF8_ERR11 : PCRE_UTF8_ERR12; + } + } + +#else /* Not SUPPORT_UTF */ +(void)(string); /* Keep picky compilers happy */ +(void)(length); +(void)(erroroffset); +#endif + +return PCRE_UTF8_ERR0; /* This indicates success */ +} + +/* End of pcre_valid_utf8.c */ |