jsregexp.c

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    uintN value = JS7_UNDEC(c);
    JSBool overflow = (value > max && (!findMax || value > findMax(state)));

    /* The following restriction allows simpler overflow checks. */
    JS_ASSERT(max <= ((uintN)-1 - 9) / 10);
    while (state->cp < state->cpend) {
        c = *state->cp;
        if (!JS7_ISDEC(c))
            break;
        value = 10 * value + JS7_UNDEC(c);
        if (!overflow && value > max && (!findMax || value > findMax(state)))
            overflow = JS_TRUE;
        ++state->cp;
    }
    return overflow ? OVERFLOW_VALUE : value;
}

/*
 * Calculate the total size of the bitmap required for a class expression.
 */
static JSBool
CalculateBitmapSize(CompilerState *state, RENode *target, const jschar *src,
                    const jschar *end)
{
    uintN max = 0;
    JSBool inRange = JS_FALSE;
    jschar c, rangeStart = 0;
    uintN n, digit, nDigits, i;

    target->u.ucclass.bmsize = 0;
    target->u.ucclass.sense = JS_TRUE;

    if (src == end)
        return JS_TRUE;

    if (*src == '^') {
        ++src;
        target->u.ucclass.sense = JS_FALSE;
    }

    while (src != end) {
        uintN localMax = 0;
        switch (*src) {
        case '\\':
            ++src;
            c = *src++;
            switch (c) {
            case 'b':
                localMax = 0x8;
                break;
            case 'f':
                localMax = 0xC;
                break;
            case 'n':
                localMax = 0xA;
                break;
            case 'r':
                localMax = 0xD;
                break;
            case 't':
                localMax = 0x9;
                break;
            case 'v':
                localMax = 0xB;
                break;
            case 'c':
                if (src + 1 < end && RE_IS_LETTER(src[1]))
                    localMax = (jschar) (*src++ & 0x1F);
                else
                    localMax = '\\';
                break;
            case 'x':
                nDigits = 2;
                goto lexHex;
            case 'u':
                nDigits = 4;
lexHex:
                n = 0;
                for (i = 0; (i < nDigits) && (src < end); i++) {
                    c = *src++;
                    if (!isASCIIHexDigit(c, &digit)) {
                        /*
                         * Back off to accepting the original
                         *'\' as a literal.
                         */
                        src -= i + 1;
                        n = '\\';
                        break;
                    }
                    n = (n << 4) | digit;
                }
                localMax = n;
                break;
            case 'd':
                if (inRange) {
                    JS_ReportErrorNumber(state->context,
                                         js_GetErrorMessage, NULL,
                                         JSMSG_BAD_CLASS_RANGE);
                    return JS_FALSE;
                }
                localMax = '9';
                break;
            case 'D':
            case 's':
            case 'S':
            case 'w':
            case 'W':
                if (inRange) {
                    JS_ReportErrorNumber(state->context,
                                         js_GetErrorMessage, NULL,
                                         JSMSG_BAD_CLASS_RANGE);
                    return JS_FALSE;
                }
                target->u.ucclass.bmsize = 65535;
                return JS_TRUE;
            case '0':
            case '1':
            case '2':
            case '3':
            case '4':
            case '5':
            case '6':
            case '7':
                /*
                 *  This is a non-ECMA extension - decimal escapes (in this
                 *  case, octal!) are supposed to be an error inside class
                 *  ranges, but supported here for backwards compatibility.
                 *
                 */
                n = JS7_UNDEC(c);
                c = *src;
                if ('0' <= c && c <= '7') {
                    src++;
                    n = 8 * n + JS7_UNDEC(c);
                    c = *src;
                    if ('0' <= c && c <= '7') {
                        src++;
                        i = 8 * n + JS7_UNDEC(c);
                        if (i <= 0377)
                            n = i;
                        else
                            src--;
                    }
                }
                localMax = n;
                break;

            default:
                localMax = c;
                break;
            }
            break;
        default:
            localMax = *src++;
            break;
        }
        if (inRange) {
            if (rangeStart > localMax) {
                JS_ReportErrorNumber(state->context,
                                     js_GetErrorMessage, NULL,
                                     JSMSG_BAD_CLASS_RANGE);
                return JS_FALSE;
            }
            inRange = JS_FALSE;
        } else {
            if (src < end - 1) {
                if (*src == '-') {
                    ++src;
                    inRange = JS_TRUE;
                    rangeStart = (jschar)localMax;
                    continue;
                }
            }
        }
        if (state->flags & JSREG_FOLD) {
            c = JS_MAX(upcase((jschar)localMax), downcase((jschar)localMax));
            if (c > localMax)
                localMax = c;
        }
        if (localMax > max)
            max = localMax;
    }
    target->u.ucclass.bmsize = max;
    return JS_TRUE;
}

/*
 *  item:       assertion               An item is either an assertion or
 *              quantatom               a quantified atom.
 *
 *  assertion:  '^'                     Assertions match beginning of string
 *                                      (or line if the class static property
 *                                      RegExp.multiline is true).
 *              '$'                     End of string (or line if the class
 *                                      static property RegExp.multiline is
 *                                      true).
 *              '\b'                    Word boundary (between \w and \W).
 *              '\B'                    Word non-boundary.
 *
 *  quantatom:  atom                    An unquantified atom.
 *              quantatom '{' n ',' m '}'
 *                                      Atom must occur between n and m times.
 *              quantatom '{' n ',' '}' Atom must occur at least n times.
 *              quantatom '{' n '}'     Atom must occur exactly n times.
 *              quantatom '*'           Zero or more times (same as {0,}).
 *              quantatom '+'           One or more times (same as {1,}).
 *              quantatom '?'           Zero or one time (same as {0,1}).
 *
 *              any of which can be optionally followed by '?' for ungreedy
 *
 *  atom:       '(' regexp ')'          A parenthesized regexp (what matched
 *                                      can be addressed using a backreference,
 *                                      see '\' n below).
 *              '.'                     Matches any char except '\n'.
 *              '[' classlist ']'       A character class.
 *              '[' '^' classlist ']'   A negated character class.
 *              '\f'                    Form Feed.
 *              '\n'                    Newline (Line Feed).
 *              '\r'                    Carriage Return.
 *              '\t'                    Horizontal Tab.
 *              '\v'                    Vertical Tab.
 *              '\d'                    A digit (same as [0-9]).
 *              '\D'                    A non-digit.
 *              '\w'                    A word character, [0-9a-z_A-Z].
 *              '\W'                    A non-word character.
 *              '\s'                    A whitespace character, [ \b\f\n\r\t\v].
 *              '\S'                    A non-whitespace character.
 *              '\' n                   A backreference to the nth (n decimal
 *                                      and positive) parenthesized expression.
 *              '\' octal               An octal escape sequence (octal must be
 *                                      two or three digits long, unless it is
 *                                      0 for the null character).
 *              '\x' hex                A hex escape (hex must be two digits).
 *              '\u' unicode            A unicode escape (must be four digits).
 *              '\c' ctrl               A control character, ctrl is a letter.
 *              '\' literalatomchar     Any character except one of the above
 *                                      that follow '\' in an atom.
 *              otheratomchar           Any character not first among the other
 *                                      atom right-hand sides.
 */
static JSBool
ParseTerm(CompilerState *state)
{
    jschar c = *state->cp++;
    uintN nDigits;
    uintN num, tmp, n, i;
    const jschar *termStart;

    switch (c) {
    /* assertions and atoms */
    case '^':
        state->result = NewRENode(state, REOP_BOL);
        if (!state->result)
            return JS_FALSE;
        state->progLength++;
        return JS_TRUE;
    case '$':
        state->result = NewRENode(state, REOP_EOL);
        if (!state->result)
            return JS_FALSE;
        state->progLength++;
        return JS_TRUE;
    case '\\':
        if (state->cp >= state->cpend) {
            /* a trailing '\' is an error */
            js_ReportCompileErrorNumber(state->context, state->tokenStream,
                                        NULL, JSREPORT_ERROR,
                                        JSMSG_TRAILING_SLASH);
            return JS_FALSE;
        }
        c = *state->cp++;
        switch (c) {
        /* assertion escapes */
        case 'b' :
            state->result = NewRENode(state, REOP_WBDRY);
            if (!state->result)
                return JS_FALSE;
            state->progLength++;
            return JS_TRUE;
        case 'B':
            state->result = NewRENode(state, REOP_WNONBDRY);
            if (!state->result)
                return JS_FALSE;
            state->progLength++;
            return JS_TRUE;
        /* Decimal escape */
        case '0':
            if (JS_HAS_STRICT_OPTION(state->context)) {
                if (!js_ReportCompileErrorNumber(state->context,
                                                 state->tokenStream,
                                                 NULL,
                                                 JSREPORT_WARNING |
                                                 JSREPORT_STRICT,
                                                 JSMSG_INVALID_BACKREF)) {
                    return JS_FALSE;
                }
                c = 0;
            } else {
     doOctal:
                num = 0;
                while (state->cp < state->cpend) {
                    c = *state->cp;
                    if (c < '0' || '7' < c)
                        break;
                    state->cp++;
                    tmp = 8 * num + (uintN)JS7_UNDEC(c);
                    if (tmp > 0377)
                        break;
                    num = tmp;
                }
                c = (jschar)num;
            }
    doFlat:
            state->result = NewRENode(state, REOP_FLAT);
            if (!state->result)
                return JS_FALSE;
            state->result->u.flat.chr = c;
            state->result->u.flat.length = 1;
            state->progLength += 3;
            break;
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
            termStart = state->cp - 1;
            num = GetDecimalValue(c, state->parenCount, FindParenCount, state);
            if (state->flags & JSREG_FIND_PAREN_ERROR)
                return JS_FALSE;
            if (num == OVERFLOW_VALUE) {
                if (!JS_HAS_STRICT_OPTION(state->context)) {
                    state->cp = termStart;
                    goto doOctal;
                }
                if (!js_ReportCompileErrorNumber(state->context,
                                                 state->tokenStream,
                                                 NULL,
                                                 JSREPORT_WARNING |
                                                 JSREPORT_STRICT,
                                                 (c >= '8')
                                                 ? JSMSG_INVALID_BACKREF
                                                 : JSMSG_BAD_BACKREF)) {
                    return JS_FALSE;
                }
                num = 0x10000;
            }
            JS_ASSERT(1 <= num && num <= 0x10000);
            state->result = NewRENode(state, REOP_BACKREF);
            if (!state->result)
                return JS_FALSE;
            state->result->u.parenIndex = num - 1;
            state->progLength += 3;
            break;
        /* Control escape */
        case 'f':
            c = 0xC;
            goto doFlat;
        case 'n':
            c = 0xA;
            goto doFlat;
        case 'r':
            c = 0xD;
            goto doFlat;