regc_locale.c

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/*
 * regc_locale.c --
 *
 *  This file contains locale-specific regexp routines.
 *  This file is #included by regcomp.c.
 *
 * Copyright (c) 1998 by Scriptics Corporation.
 *
 * This software is copyrighted by the Regents of the University of
 * California, Sun Microsystems, Inc., Scriptics Corporation, ActiveState
 * Corporation and other parties.  The following terms apply to all files
 * associated with the software unless explicitly disclaimed in
 * individual files.
 *
 * The authors hereby grant permission to use, copy, modify, distribute,
 * and license this software and its documentation for any purpose, provided
 * that existing copyright notices are retained in all copies and that this
 * notice is included verbatim in any distributions. No written agreement,
 * license, or royalty fee is required for any of the authorized uses.
 * Modifications to this software may be copyrighted by their authors
 * and need not follow the licensing terms described here, provided that
 * the new terms are clearly indicated on the first page of each file where
 * they apply.
 *
 * IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY
 * FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
 * DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.  THIS SOFTWARE
 * IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE
 * NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
 * MODIFICATIONS.
 *
 * GOVERNMENT USE: If you are acquiring this software on behalf of the
 * U.S. government, the Government shall have only "Restricted Rights"
 * in the software and related documentation as defined in the Federal
 * Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2).  If you
 * are acquiring the software on behalf of the Department of Defense, the
 * software shall be classified as "Commercial Computer Software" and the
 * Government shall have only "Restricted Rights" as defined in Clause
 * 252.227-7013 (c) (1) of DFARs.  Notwithstanding the foregoing, the
 * authors grant the U.S. Government and others acting in its behalf
 * permission to use and distribute the software in accordance with the
 * terms specified in this license.
 *
 * src/backend/regex/regc_locale.c
 */

/* ASCII character-name table */

static const struct cname
{
    const char *name;
    const char  code;
}   cnames[] =

{
    {
        "NUL", '\0'
    },
    {
        "SOH", '\001'
    },
    {
        "STX", '\002'
    },
    {
        "ETX", '\003'
    },
    {
        "EOT", '\004'
    },
    {
        "ENQ", '\005'
    },
    {
        "ACK", '\006'
    },
    {
        "BEL", '\007'
    },
    {
        "alert", '\007'
    },
    {
        "BS", '\010'
    },
    {
        "backspace", '\b'
    },
    {
        "HT", '\011'
    },
    {
        "tab", '\t'
    },
    {
        "LF", '\012'
    },
    {
        "newline", '\n'
    },
    {
        "VT", '\013'
    },
    {
        "vertical-tab", '\v'
    },
    {
        "FF", '\014'
    },
    {
        "form-feed", '\f'
    },
    {
        "CR", '\015'
    },
    {
        "carriage-return", '\r'
    },
    {
        "SO", '\016'
    },
    {
        "SI", '\017'
    },
    {
        "DLE", '\020'
    },
    {
        "DC1", '\021'
    },
    {
        "DC2", '\022'
    },
    {
        "DC3", '\023'
    },
    {
        "DC4", '\024'
    },
    {
        "NAK", '\025'
    },
    {
        "SYN", '\026'
    },
    {
        "ETB", '\027'
    },
    {
        "CAN", '\030'
    },
    {
        "EM", '\031'
    },
    {
        "SUB", '\032'
    },
    {
        "ESC", '\033'
    },
    {
        "IS4", '\034'
    },
    {
        "FS", '\034'
    },
    {
        "IS3", '\035'
    },
    {
        "GS", '\035'
    },
    {
        "IS2", '\036'
    },
    {
        "RS", '\036'
    },
    {
        "IS1", '\037'
    },
    {
        "US", '\037'
    },
    {
        "space", ' '
    },
    {
        "exclamation-mark", '!'
    },
    {
        "quotation-mark", '"'
    },
    {
        "number-sign", '#'
    },
    {
        "dollar-sign", '$'
    },
    {
        "percent-sign", '%'
    },
    {
        "ampersand", '&'
    },
    {
        "apostrophe", '\''
    },
    {
        "left-parenthesis", '('
    },
    {
        "right-parenthesis", ')'
    },
    {
        "asterisk", '*'
    },
    {
        "plus-sign", '+'
    },
    {
        "comma", ','
    },
    {
        "hyphen", '-'
    },
    {
        "hyphen-minus", '-'
    },
    {
        "period", '.'
    },
    {
        "full-stop", '.'
    },
    {
        "slash", '/'
    },
    {
        "solidus", '/'
    },
    {
        "zero", '0'
    },
    {
        "one", '1'
    },
    {
        "two", '2'
    },
    {
        "three", '3'
    },
    {
        "four", '4'
    },
    {
        "five", '5'
    },
    {
        "six", '6'
    },
    {
        "seven", '7'
    },
    {
        "eight", '8'
    },
    {
        "nine", '9'
    },
    {
        "colon", ':'
    },
    {
        "semicolon", ';'
    },
    {
        "less-than-sign", '<'
    },
    {
        "equals-sign", '='
    },
    {
        "greater-than-sign", '>'
    },
    {
        "question-mark", '?'
    },
    {
        "commercial-at", '@'
    },
    {
        "left-square-bracket", '['
    },
    {
        "backslash", '\\'
    },
    {
        "reverse-solidus", '\\'
    },
    {
        "right-square-bracket", ']'
    },
    {
        "circumflex", '^'
    },
    {
        "circumflex-accent", '^'
    },
    {
        "underscore", '_'
    },
    {
        "low-line", '_'
    },
    {
        "grave-accent", '`'
    },
    {
        "left-brace", '{'
    },
    {
        "left-curly-bracket", '{'
    },
    {
        "vertical-line", '|'
    },
    {
        "right-brace", '}'
    },
    {
        "right-curly-bracket", '}'
    },
    {
        "tilde", '~'
    },
    {
        "DEL", '\177'
    },
    {
        NULL, 0
    }
};


/*
 * We do not use the hard-wired Unicode classification tables that Tcl does.
 * This is because (a) we need to deal with other encodings besides Unicode,
 * and (b) we want to track the behavior of the libc locale routines as
 * closely as possible.  For example, it wouldn't be unreasonable for a
 * locale to not consider every Unicode letter as a letter.  So we build
 * character classification cvecs by asking libc, even for Unicode.
 */


/*
 * element - map collating-element name to celt
 */
static celt
element(struct vars * v,        /* context */
        const chr *startp,      /* points to start of name */
        const chr *endp)        /* points just past end of name */
{
    const struct cname *cn;
    size_t      len;

    /* generic:  one-chr names stand for themselves */
    assert(startp < endp);
    len = endp - startp;
    if (len == 1)
        return *startp;

    NOTE(REG_ULOCALE);

    /* search table */
    for (cn = cnames; cn->name != NULL; cn++)
    {
        if (strlen(cn->name) == len &&
            pg_char_and_wchar_strncmp(cn->name, startp, len) == 0)
        {
            break;              /* NOTE BREAK OUT */
        }
    }
    if (cn->name != NULL)
        return CHR(cn->code);

    /* couldn't find it */
    ERR(REG_ECOLLATE);
    return 0;
}

/*
 * range - supply cvec for a range, including legality check
 */
static struct cvec *
range(struct vars * v,          /* context */
      celt a,                   /* range start */
      celt b,                   /* range end, might equal a */
      int cases)                /* case-independent? */
{
    int         nchrs;
    struct cvec *cv;
    celt        c,
                lc,
                uc;

    if (a != b && !before(a, b))
    {
        ERR(REG_ERANGE);
        return NULL;
    }

    if (!cases)
    {                           /* easy version */
        cv = getcvec(v, 0, 1);
        NOERRN();
        addrange(cv, a, b);
        return cv;
    }

    /*
     * When case-independent, it's hard to decide when cvec ranges are usable,
     * so for now at least, we won't try.  We allocate enough space for two
     * case variants plus a little extra for the two title case variants.
     */

    nchrs = (b - a + 1) * 2 + 4;

    cv = getcvec(v, nchrs, 0);
    NOERRN();

    for (c = a; c <= b; c++)
    {
        addchr(cv, c);
        lc = pg_wc_tolower((chr) c);
        if (c != lc)
            addchr(cv, lc);
        uc = pg_wc_toupper((chr) c);
        if (c != uc)
            addchr(cv, uc);
    }

    return cv;
}

/*
 * before - is celt x before celt y, for purposes of range legality?
 */
static int                      /* predicate */
before(celt x, celt y)
{
    if (x < y)
        return 1;
    return 0;
}

/*
 * eclass - supply cvec for an equivalence class
 * Must include case counterparts on request.
 */
static struct cvec *
eclass(struct vars * v,         /* context */
       celt c,                  /* Collating element representing the
                                 * equivalence class. */
       int cases)               /* all cases? */
{
    struct cvec *cv;

    /* crude fake equivalence class for testing */
    if ((v->cflags & REG_FAKE) && c == 'x')
    {
        cv = getcvec(v, 4, 0);
        addchr(cv, (chr) 'x');
        addchr(cv, (chr) 'y');
        if (cases)
        {
            addchr(cv, (chr) 'X');
            addchr(cv, (chr) 'Y');
        }
        return cv;
    }

    /* otherwise, none */
    if (cases)
        return allcases(v, c);
    cv = getcvec(v, 1, 0);
    assert(cv != NULL);
    addchr(cv, (chr) c);
    return cv;
}

/*
 * cclass - supply cvec for a character class
 *
 * Must include case counterparts if "cases" is true.
 *
 * The returned cvec might be either a transient cvec gotten from getcvec(),
 * or a permanently cached one from pg_ctype_get_cache().  This is okay
 * because callers are not supposed to explicitly free the result either way.
 */
static struct cvec *
cclass(struct vars * v,         /* context */
       const chr *startp,       /* where the name starts */
       const chr *endp,         /* just past the end of the name */
       int cases)               /* case-independent? */
{
    size_t      len;
    struct cvec *cv = NULL;
    const char *const * namePtr;
    int         i,
                index;

    /*
     * The following arrays define the valid character class names.
     */

    static const char *const classNames[] = {
        "alnum", "alpha", "ascii", "blank", "cntrl", "digit", "graph",
        "lower", "print", "punct", "space", "upper", "xdigit", NULL
    };

    enum classes
    {
        CC_ALNUM, CC_ALPHA, CC_ASCII, CC_BLANK, CC_CNTRL, CC_DIGIT, CC_GRAPH,
        CC_LOWER, CC_PRINT, CC_PUNCT, CC_SPACE, CC_UPPER, CC_XDIGIT
    };

    /*
     * Map the name to the corresponding enumerated value.
     */
    len = endp - startp;
    index = -1;
    for (namePtr = classNames, i = 0; *namePtr != NULL; namePtr++, i++)
    {
        if (strlen(*namePtr) == len &&
            pg_char_and_wchar_strncmp(*namePtr, startp, len) == 0)
        {
            index = i;
            break;
        }
    }
    if (index == -1)
    {
        ERR(REG_ECTYPE);
        return NULL;
    }

    /*
     * Remap lower and upper to alpha if the match is case insensitive.
     */

    if (cases &&
        ((enum classes) index == CC_LOWER ||
         (enum classes) index == CC_UPPER))
        index = (int) CC_ALPHA;

    /*
     * Now compute the character class contents.  For classes that are based
     * on the behavior of a <wctype.h> or <ctype.h> function, we use
     * pg_ctype_get_cache so that we can cache the results.  Other classes
     * have definitions that are hard-wired here, and for those we just
     * construct a transient cvec on the fly.
     */

    switch ((enum classes) index)
    {
        case CC_PRINT:
            cv = pg_ctype_get_cache(pg_wc_isprint);
            break;
        case CC_ALNUM:
            cv = pg_ctype_get_cache(pg_wc_isalnum);
            break;
        case CC_ALPHA:
            cv = pg_ctype_get_cache(pg_wc_isalpha);
            break;
        case CC_ASCII:
            /* hard-wired meaning */
            cv = getcvec(v, 0, 1);
            if (cv)
                addrange(cv, 0, 0x7f);
            break;
        case CC_BLANK:
            /* hard-wired meaning */
            cv = getcvec(v, 2, 0);
            addchr(cv, '\t');
            addchr(cv, ' ');
            break;
        case CC_CNTRL:
            /* hard-wired meaning */
            cv = getcvec(v, 0, 2);
            addrange(cv, 0x0, 0x1f);
            addrange(cv, 0x7f, 0x9f);
            break;
        case CC_DIGIT:
            cv = pg_ctype_get_cache(pg_wc_isdigit);
            break;
        case CC_PUNCT:
            cv = pg_ctype_get_cache(pg_wc_ispunct);
            break;
        case CC_XDIGIT:

            /*
             * It's not clear how to define this in non-western locales, and
             * even less clear that there's any particular use in trying. So
             * just hard-wire the meaning.
             */
            cv = getcvec(v, 0, 3);
            if (cv)
            {
                addrange(cv, '0', '9');
                addrange(cv, 'a', 'f');
                addrange(cv, 'A', 'F');
            }
            break;
        case CC_SPACE:
            cv = pg_ctype_get_cache(pg_wc_isspace);
            break;
        case CC_LOWER:
            cv = pg_ctype_get_cache(pg_wc_islower);
            break;
        case CC_UPPER:
            cv = pg_ctype_get_cache(pg_wc_isupper);
            break;
        case CC_GRAPH:
            cv = pg_ctype_get_cache(pg_wc_isgraph);
            break;
    }

    /* If cv is NULL now, the reason must be "out of memory" */
    if (cv == NULL)
        ERR(REG_ESPACE);
    return cv;
}

/*
 * allcases - supply cvec for all case counterparts of a chr (including itself)
 *
 * This is a shortcut, preferably an efficient one, for simple characters;
 * messy cases are done via range().
 */
static struct cvec *
allcases(struct vars * v,       /* context */
         chr pc)                /* character to get case equivs of */
{
    struct cvec *cv;
    chr         c = (chr) pc;
    chr         lc,
                uc;

    lc = pg_wc_tolower((chr) c);
    uc = pg_wc_toupper((chr) c);

    cv = getcvec(v, 2, 0);
    addchr(cv, lc);
    if (lc != uc)
        addchr(cv, uc);
    return cv;
}

/*
 * cmp - chr-substring compare
 *
 * Backrefs need this.  It should preferably be efficient.
 * Note that it does not need to report anything except equal/unequal.
 * Note also that the length is exact, and the comparison should not
 * stop at embedded NULs!
 */
static int                      /* 0 for equal, nonzero for unequal */
cmp(const chr *x, const chr *y, /* strings to compare */
    size_t len)                 /* exact length of comparison */
{
    return memcmp(VS(x), VS(y), len * sizeof(chr));
}

/*
 * casecmp - case-independent chr-substring compare
 *
 * REG_ICASE backrefs need this.  It should preferably be efficient.
 * Note that it does not need to report anything except equal/unequal.
 * Note also that the length is exact, and the comparison should not
 * stop at embedded NULs!
 */
static int                      /* 0 for equal, nonzero for unequal */
casecmp(const chr *x, const chr *y,     /* strings to compare */
        size_t len)             /* exact length of comparison */
{
    for (; len > 0; len--, x++, y++)
    {
        if ((*x != *y) && (pg_wc_tolower(*x) != pg_wc_tolower(*y)))
            return 1;
    }
    return 0;
}