X-Git-Url: https://git.pterodactylus.net/?a=blobdiff_plain;f=src%2Fnntp%2Fuwildmat.cpp;fp=src%2Fnntp%2Fuwildmat.cpp;h=f726410eab00f48e6ebe85fc30f0583a16c97563;hb=6b896a9e1dc143bba86795be1e9336549db9b85f;hp=0000000000000000000000000000000000000000;hpb=8adfd604a97d385869b0ce763b35d014d7aa2cca;p=fms.git diff --git a/src/nntp/uwildmat.cpp b/src/nntp/uwildmat.cpp new file mode 100644 index 0000000..f726410 --- /dev/null +++ b/src/nntp/uwildmat.cpp @@ -0,0 +1,403 @@ +/* $Id: uwildmat.c 6779 2004-05-17 07:25:28Z rra $ +** +** wildmat pattern matching with Unicode UTF-8 extensions. +** +** Do shell-style pattern matching for ?, \, [], and * characters. Might not +** be robust in face of malformed patterns; e.g., "foo[a-" could cause a +** segmentation violation. It is 8-bit clean. (Robustness hopefully fixed +** July 2000; all malformed patterns should now just fail to match anything.) +** +** Original by Rich $alz, mirror!rs, Wed Nov 26 19:03:17 EST 1986. +** Rich $alz is now . +** +** April, 1991: Replaced mutually-recursive calls with in-line code for the +** star character. +** +** Special thanks to Lars Mathiesen for the ABORT code. +** This can greatly speed up failing wildcard patterns. For example: +** +** pattern: -*-*-*-*-*-*-12-*-*-*-m-*-*-* +** text 1: -adobe-courier-bold-o-normal--12-120-75-75-m-70-iso8859-1 +** text 2: -adobe-courier-bold-o-normal--12-120-75-75-X-70-iso8859-1 +** +** Text 1 matches with 51 calls, while text 2 fails with 54 calls. Without +** the ABORT code, it takes 22310 calls to fail. Ugh. The following +** explanation is from Lars: +** +** The precondition that must be fulfilled is that DoMatch will consume at +** least one character in text. This is true if *p is neither '*' nor '\0'.) +** The last return has ABORT instead of false to avoid quadratic behaviour in +** cases like pattern "*a*b*c*d" with text "abcxxxxx". With false, each +** star-loop has to run to the end of the text; with ABORT only the last one +** does. +** +** Once the control of one instance of DoMatch enters the star-loop, that +** instance will return either true or ABORT, and any calling instance will +** therefore return immediately after (without calling recursively again). +** In effect, only one star-loop is ever active. It would be possible to +** modify the code to maintain this context explicitly, eliminating all +** recursive calls at the cost of some complication and loss of clarity (and +** the ABORT stuff seems to be unclear enough by itself). I think it would +** be unwise to try to get this into a released version unless you have a +** good test data base to try it out on. +** +** June, 1991: Robert Elz added minus and close bracket +** handling for character sets. +** +** July, 2000: Largely rewritten by Russ Allbery to add +** support for ',', '!', and optionally '@' to the core wildmat routine. +** Broke the character class matching into a separate function for clarity +** since it's infrequently used in practice, and added some simple lookahead +** to significantly decrease the recursive calls in the '*' matching code. +** Added support for UTF-8 as the default character set for any high-bit +** characters. +** +** For more information on UTF-8, see RFC 2279. +** +** Please note that this file is intentionally written so that conditionally +** executed expressions are on separate lines from the condition to +** facilitate analysis of the coverage of the test suite using purecov. +** Please preserve this. As of March 11, 2001, purecov reports that the +** accompanying test suite achieves 100% coverage of this file. +*/ + +//#include "config.h" +//#include "clibrary.h" +//#include "libinn.h" +#include "../../include/nntp/uwildmat.h" +#include + +#define ABORT -1 + +/* Whether or not an octet looks like the start of a UTF-8 character. */ +#define ISUTF8(c) (((c) & 0xc0) == 0xc0) + + +/* +** Determine the length of a non-ASCII character in octets (for advancing +** pointers when skipping over characters). Takes a pointer to the start of +** the character and to the last octet of the string. If end is NULL, expect +** the string pointed to by start to be nul-terminated. If the character is +** malformed UTF-8, return 1 to treat it like an eight-bit local character. +*/ +static int +utf8_length(const unsigned char *start, const unsigned char *end) +{ + unsigned char mask = 0x80; + const unsigned char *p; + int length = 0; + int left; + + for (; mask > 0 && (*start & mask) == mask; mask >>= 1) + length++; + if (length < 2 || length > 6) + return 1; + if (end != NULL && (end - start + 1) < length) + return 1; + left = length - 1; + p = start + 1; + for (p = start + 1; left > 0 && (*p & 0xc0) == 0x80; p++) + left--; + return (left == 0) ? length : 1; +} + + +/* +** Convert a UTF-8 character to UCS-4. Takes a pointer to the start of the +** character and to the last octet of the string, and to a uint32_t into +** which to put the decoded UCS-4 value. If end is NULL, expect the string +** pointed to by start to be nul-terminated. Returns the number of octets in +** the UTF-8 encoding. If the UTF-8 character is malformed, set result to +** the decimal value of the first octet; this is wrong, but it will generally +** cause the rest of the wildmat matching to do the right thing for non-UTF-8 +** input. +*/ +static int +utf8_decode(const unsigned char *start, const unsigned char *end, + uint32_t *result) +{ + uint32_t value = 0; + int length, i; + const unsigned char *p = start; + unsigned char mask; + + length = utf8_length(start, end); + if (length < 2) { + *result = *start; + return 1; + } + mask = (1 << (7 - length)) - 1; + value = *p & mask; + p++; + for (i = length - 1; i > 0; i--) { + value = (value << 6) | (*p & 0x3f); + p++; + } + *result = value; + return length; +} + + +/* +** Match a character class against text, a UCS-4 character. start is a +** pointer to the first character of the character class, end a pointer to +** the last. Returns whether the class matches that character. +*/ +static bool +match_class(uint32_t text, const unsigned char *start, + const unsigned char *end) +{ + bool reversed, allowrange; + const unsigned char *p = start; + uint32_t first, last; + + /* Check for an inverted character class (starting with ^). If the + character matches the character class, we return !reversed; that way, + we return true if it's a regular character class and false if it's a + reversed one. If the character doesn't match, we return reversed. */ + reversed = (*p == '^'); + if (reversed) + p++; + + /* Walk through the character class until we reach the end or find a + match, handling character ranges as we go. Only permit a range to + start when allowrange is true; this allows - to be treated like a + normal character as the first character of the class and catches + malformed ranges like a-e-n. We treat the character at the beginning + of a range as both a regular member of the class and the beginning of + the range; this is harmless (although it means that malformed ranges + like m-a will match m and nothing else). */ + allowrange = false; + while (p <= end) { + if (allowrange && *p == '-' && p < end) { + p++; + p += utf8_decode(p, end, &last); + if (text >= first && text <= last) + return !reversed; + allowrange = false; + } else { + p += utf8_decode(p, end, &first); + if (text == first) + return !reversed; + allowrange = true; + } + } + return reversed; +} + + +/* +** Match the text against the pattern between start and end. This is a +** single pattern; a leading ! or @ must already be taken care of, and +** commas must be dealt with outside of this routine. +*/ +static int +match_pattern(const unsigned char *text, const unsigned char *start, + const unsigned char *end) +{ + const unsigned char *q, *endclass; + const unsigned char *p = start; + bool ismeta; + int matched, width; + uint32_t c; + + for (; p <= end; p++) { + if (!*text && *p != '*') + return ABORT; + + switch (*p) { + case '\\': + if (!*++p) + return ABORT; + /* Fall through. */ + + default: + if (*text++ != *p) + return false; + break; + + case '?': + text += ISUTF8(*text) ? utf8_length(text, NULL) : 1; + break; + + case '*': + /* Consecutive stars are equivalent to one. Advance pattern to + the character after the star. */ + for (++p; *p == '*'; p++) + ; + + /* A trailing star will match anything. */ + if (p > end) + return true; + + /* Basic algorithm: Recurse at each point where the * could + possibly match. If the match succeeds or aborts, return + immediately; otherwise, try the next position. + + Optimization: If the character after the * in the pattern + isn't a metacharacter (the common case), then the * has to + consume characters at least up to the next occurance of that + character in the text. Scan forward for those points rather + than recursing at every possible point to save the extra + function call overhead. */ + ismeta = (*p == '[' || *p == '?' || *p == '\\'); + while (*text) { + width = ISUTF8(*text) ? utf8_length(text, NULL) : 1; + if (ismeta) { + matched = match_pattern(text, p, end); + text += width; + } else { + while (*text && *text != *p) { + text += width; + width = ISUTF8(*text) ? utf8_length(text, NULL) : 1; + } + if (!*text) + return ABORT; + matched = match_pattern(++text, p + 1, end); + } + if (matched != false) + return matched; + } + return ABORT; + + case '[': + /* Find the end of the character class, making sure not to pick + up a close bracket at the beginning of the class. */ + p++; + q = p + (*p == '^') + 1; + if (q > end) + return ABORT; + endclass = (unsigned char *)memchr(q, ']', (size_t) (end - q + 1)); + if (!endclass) + return ABORT; + + /* Do the heavy lifting in another function for clarity, since + character classes are an uncommon case. */ + text += utf8_decode(text, NULL, &c); + if (!match_class(c, p, endclass - 1)) + return false; + p = endclass; + break; + } + } + + return (*text == '\0'); +} + + +/* +** Takes text and a wildmat expression; a wildmat expression is a +** comma-separated list of wildmat patterns, optionally preceeded by ! to +** invert the sense of the expression. Returns WILDMAT_MATCH if that +** expression matches the text, WILDMAT_FAIL otherwise. If allowpoison is +** set, allow @ to introduce a poison expression (the same as !, but if it +** triggers the failed match the routine returns WILDMAT_POISON instead). +*/ +static enum uwildmat +match_expression(const unsigned char *text, const unsigned char *start, + bool allowpoison) +{ + const unsigned char *end, *split; + const unsigned char *p = start; + bool reverse, escaped; + bool match = false; + bool poison = false; + bool poisoned = false; + + /* Handle the empty expression separately, since otherwise end will be + set to an invalid pointer. */ + if (!*p) + return !*text ? UWILDMAT_MATCH : UWILDMAT_FAIL; + end = start + strlen((const char *) start) - 1; + + /* Main match loop. Find each comma that separates patterns, and attempt + to match the text with each pattern in order. The last matching + pattern determines whether the whole expression matches. */ + for (; p <= end + 1; p = split + 1) { + if (allowpoison) + poison = (*p == '@'); + reverse = (*p == '!') || poison; + if (reverse) + p++; + + /* Find the first unescaped comma, if any. If there is none, split + will be one greater than end and point at the nul at the end of + the string. */ + for (escaped = false, split = p; split <= end; split++) { + if (*split == '[') { + split++; + if (*split == ']') + split++; + while (split <= end && *split != ']') + split++; + } + if (*split == ',' && !escaped) + break; + escaped = (*split == '\\') ? !escaped : false; + } + + /* Optimization: If match == !reverse and poison == poisoned, this + pattern can't change the result, so don't do any work. */ + if (match == !reverse && poison == poisoned) + continue; + if (match_pattern(text, p, split - 1) == true) { + poisoned = poison; + match = !reverse; + } + } + if (poisoned) + return UWILDMAT_POISON; + return match ? UWILDMAT_MATCH : UWILDMAT_FAIL; +} + + +/* +** User-level routine used for wildmats where @ should be treated as a +** regular character. +*/ +bool +uwildmat(const char *text, const char *pat) +{ + const unsigned char *utext = (const unsigned char *) text; + const unsigned char *upat = (const unsigned char *) pat; + + if (upat[0] == '*' && upat[1] == '\0') + return true; + else + return (match_expression(utext, upat, false) == UWILDMAT_MATCH); +} + + +/* +** User-level routine used for wildmats that support poison matches. +*/ +enum uwildmat +uwildmat_poison(const char *text, const char *pat) +{ + const unsigned char *utext = (const unsigned char *) text; + const unsigned char *upat = (const unsigned char *) pat; + + if (upat[0] == '*' && upat[1] == '\0') + return UWILDMAT_MATCH; + else + return match_expression(utext, upat, true); +} + + +/* +** User-level routine for simple expressions (neither , nor ! are special). +*/ +bool +uwildmat_simple(const char *text, const char *pat) +{ + const unsigned char *utext = (const unsigned char *) text; + const unsigned char *upat = (const unsigned char *) pat; + size_t length; + + if (upat[0] == '*' && upat[1] == '\0') + return true; + else { + length = strlen(pat); + return (match_pattern(utext, upat, upat + length - 1) == true); + } +}