Quelle _eval.c Sprache: C

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
*   Licensed to the Apache Software Foundation (ASF) under one or more
*   contributor license agreements. See the NOTICE file distributed
*   with this work for additional information regarding copyright
*   ownership. The ASF licenses this file to you under the Apache
*   License, Version 2.0 (the "License"); you may not use this file
*   except in compliance with the License. You may obtain a copy of
*   the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/

#include "cpp.h"

#define NSTAK   32
#define SGN 0
#define UNS 1
#define UND 2

#define UNSMARK 0x1000

struct value
{
    int val;
    int type;
};

/* conversion types */
#define RELAT   1
#define ARITH   2
#define LOGIC   3
#define SPCL    4
#define SHIFT   5
#define UNARY   6

/* operator priority, arity, and conversion type, indexed by tokentype */
struct pri
{
    char pri;
    char arity;
    char ctype;
};

static const struct pri priority[] =
{
    {
        0, 0, 0
    },                                  /* END */
    {
        0, 0, 0
    },                                  /* UNCLASS */
    {
        0, 0, 0
    },                                  /* NAME */
    {
        0, 0, 0
    },                                  /* NUMBER */
    {
        0, 0, 0
    },                                  /* STRING */
    {
        0, 0, 0
    },                                  /* CCON */
    {
        0, 0, 0
    },                                  /* NL */
    {
        0, 0, 0
    },                                  /* WS */
    {
        0, 0, 0
    },                                  /* DSHARP */
    {
        11, 2, RELAT
    },                                  /* EQ */
    {
        11, 2, RELAT
    },                                  /* NEQ */
    {
        12, 2, RELAT
    },                                  /* LEQ */
    {
        12, 2, RELAT
    },                                  /* GEQ */
    {
        13, 2, SHIFT
    },                                  /* LSH */
    {
        13, 2, SHIFT
    },                                  /* RSH */
    {
        7, 2, LOGIC
    },                                  /* LAND */
    {
        6, 2, LOGIC
    },                                  /* LOR */
    {
        0, 0, 0
    },                                  /* PPLUS */
    {
        0, 0, 0
    },                                  /* MMINUS */
    {
        0, 0, 0
    },                                  /* ARROW */
    {
        0, 0, 0
    },                                  /* SBRA */
    {
        0, 0, 0
    },                                  /* SKET */
    {
        3, 0, 0
    },                                  /* LP */
    {
        3, 0, 0
    },                                  /* RP */
    {
        0, 0, 0
    },                                  /* DOT */
    {
        10, 2, ARITH
    },                                  /* AND */
    {
        15, 2, ARITH
    },                                  /* STAR */
    {
        14, 2, ARITH
    },                                  /* PLUS */
    {
        14, 2, ARITH
    },                                  /* MINUS */
    {
        16, 1, UNARY
    },                                  /* TILDE */
    {
        16, 1, UNARY
    },                                  /* NOT */
    {
        15, 2, ARITH
    },                                  /* SLASH */
    {
        15, 2, ARITH
    },                                  /* PCT */
    {
        12, 2, RELAT
    },                                  /* LT */
    {
        12, 2, RELAT
    },                                  /* GT */
    {
        9, 2, ARITH
    },                                  /* CIRC */
    {
        8, 2, ARITH
    },                                  /* OR */
    {
        5, 2, SPCL
    },                                  /* QUEST */
    {
        5, 2, SPCL
    },                                  /* COLON */
    {
        0, 0, 0
    },                                  /* ASGN */
    {
        4, 2, 0
    },                                  /* COMMA */
    {
        0, 0, 0
    },                                  /* SHARP */
    {
        0, 0, 0
    },                                  /* SEMIC */
    {
        0, 0, 0
    },                                  /* CBRA */
    {
        0, 0, 0
    },                                  /* CKET */
    {
        0, 0, 0
    },                                  /* ASPLUS */
    {
        0, 0, 0
    },                                  /* ASMINUS */
    {
        0, 0, 0
    },                                  /* ASSTAR */
    {
        0, 0, 0
    },                                  /* ASSLASH */
    {
        0, 0, 0
    },                                  /* ASPCT */
    {
        0, 0, 0
    },                                  /* ASCIRC */
    {
        0, 0, 0
    },                                  /* ASLSH */
    {
        0, 0, 0
    },                                  /* ASRSH */
    {
        0, 0, 0
    },                                  /* ASOR */
    {
        0, 0, 0
    },                                  /* ASAND */
    {
        0, 0, 0
    },                                  /* ELLIPS */
    {
        0, 0, 0
    },                                  /* DSHARP1 */
    {
        0, 0, 0
    },                                  /* NAME1 */
    {
        0, 0, 0
    },                                  /* NAME2 */
    {
        16, 1, UNARY
    },                                  /* DEFINED */
    {
        16, 0, UNARY
    },                                  /* UMINUS */
    {
        16, 1, UNARY
    },                                  /* ARCHITECTURE */
};

static int evalop(struct pri);
static struct value tokval(Token *);
static struct value vals[NSTAK], *vp;
static enum toktype ops[NSTAK], *op;

/*
* Evaluate an #if #elif #ifdef #ifndef line.  trp->tp points to the keyword.
*/
long
    eval(Tokenrow * trp, int kw)
{
    Token *tp;
    Nlist *np;
    size_t  ntok;
    int rnd;

    trp->tp++;
    if (kw == KIFDEF || kw == KIFNDEF)
    {
        if (trp->lp - trp->bp != 4 || trp->tp->type != NAME)
        {
            error(ERROR, "Syntax error in #ifdef/#ifndef");
            return 0;
        }
        np = lookup(trp->tp, 0);
        return (kw == KIFDEF) == (np && np->flag & (ISDEFINED | ISMAC));
    }
    ntok = trp->tp - trp->bp;
    kwdefined->val = KDEFINED;          /* activate special meaning of
                                         * defined */
    expandrow(trp, "");
    kwdefined->val = NAME;
    vp = vals;
    op = ops;
    *op++ = END;
    for (rnd = 0, tp = trp->bp + ntok; tp < trp->lp; tp++)
    {
        switch (tp->type)
        {
            case WS:
            case NL:
                continue;

                /* nilary */
            case NAME:
            case NAME1:
            case NAME2:
            case NUMBER:
            case CCON:
            case STRING:
                if (rnd)
                    goto syntax;
                *vp++ = tokval(tp);
                rnd = 1;
                continue;

                /* unary */
            case DEFINED:
            case TILDE:
            case NOT:
                if (rnd)
                    goto syntax;
                *op++ = tp->type;
                continue;

                /* unary-binary */
            case PLUS:
            case MINUS:
            case STAR:
            case AND:
                if (rnd == 0)
                {
                    if (tp->type == MINUS)
                        *op++ = UMINUS;
                    if (tp->type == STAR || tp->type == AND)
                    {
                        error(ERROR, "Illegal operator * or & in #if/#elif");
                        return 0;
                    }
                    continue;
                }
                /* fall through */

                /* plain binary */
            case EQ:
            case NEQ:
            case LEQ:
            case GEQ:
            case LSH:
            case RSH:
            case LAND:
            case LOR:
            case SLASH:
            case PCT:
            case LT:
            case GT:
            case CIRC:
            case OR:
            case QUEST:
            case COLON:
            case COMMA:
                if (rnd == 0)
                    goto syntax;
                if (evalop(priority[tp->type]) != 0)
                    return 0;
                *op++ = tp->type;
                rnd = 0;
                continue;

            case LP:
                if (rnd)
                    goto syntax;
                *op++ = LP;
                continue;

            case RP:
                if (!rnd)
                    goto syntax;
                if (evalop(priority[RP]) != 0)
                    return 0;
                if (op <= ops || op[-1] != LP)
                {
                    goto syntax;
                }
                op--;
                continue;

            case SHARP:
                if ((tp + 1) < trp->lp)
                {
                    np = lookup(tp + 1, 0);
                    if (np && (np->val == KMACHINE))
                    {
                        tp++;
                        if (rnd)
                            goto syntax;
                        *op++ = ARCHITECTURE;
                        continue;
                    }
                }
                /* fall through */

            default:
                error(ERROR, "Bad operator (%t) in #if/#elif", tp);
                return 0;
        }
    }
    if (rnd == 0)
        goto syntax;
    if (evalop(priority[END]) != 0)
        return 0;
    if (op != &ops[1] || vp != &vals[1])
    {
        error(ERROR, "Botch in #if/#elif");
        return 0;
    }
    if (vals[0].type == UND)
        error(ERROR, "Undefined expression value");
    return vals[0].val;
syntax:
    error(ERROR, "Syntax error in #if/#elif");
    return 0;
}

int
    evalop(struct pri pri)
{
    struct value v1;
    struct value v2 = { 0, UND };
    int rv1, rv2;
    int rtype, oper;

    rv2 = 0;
    rtype = 0;
    while (pri.pri < priority[op[-1]].pri)
    {
        oper = *--op;
        if (priority[oper].arity == 2)
        {
            v2 = *--vp;
            rv2 = v2.val;
        }
        v1 = *--vp;
        rv1 = v1.val;
/*lint -e574 -e644 */
        switch (priority[oper].ctype)
        {
            case 0:
            default:
                error(WARNING, "Syntax error in #if/#endif");
                return 1;
            case ARITH:
            case RELAT:
                if (v1.type == UNS || v2.type == UNS)
                    rtype = UNS;
                else
                    rtype = SGN;
                if (v1.type == UND || v2.type == UND)
                    rtype = UND;
                if (priority[oper].ctype == RELAT && rtype == UNS)
                {
                    oper |= UNSMARK;
                    rtype = SGN;
                }
                break;
            case SHIFT:
                if (v1.type == UND || v2.type == UND)
                    rtype = UND;
                else
                    rtype = v1.type;
                if (rtype == UNS)
                    oper |= UNSMARK;
                break;
            case UNARY:
                rtype = v1.type;
                break;
            case LOGIC:
            case SPCL:
                break;
        }
        switch (oper)
        {
            case EQ:
            case EQ | UNSMARK:
                rv1 = rv1 == rv2;
                break;
            case NEQ:
            case NEQ | UNSMARK:
                rv1 = rv1 != rv2;
                break;
            case LEQ:
                rv1 = rv1 <= rv2;
                break;
            case GEQ:
                rv1 = rv1 >= rv2;
                break;
            case LT:
                rv1 = rv1 < rv2;
                break;
            case GT:
                rv1 = rv1 > rv2;
                break;
            case LEQ | UNSMARK:
                rv1 = (unsigned long)rv1 <= (unsigned long)rv2;
                break;
            case GEQ | UNSMARK:
                rv1 = (unsigned long)rv1 >= (unsigned long)rv2;
                break;
            case LT | UNSMARK:
                rv1 = (unsigned long)rv1 < (unsigned long)rv2;
                break;
            case GT | UNSMARK:
                rv1 = (unsigned long)rv1 > (unsigned long)rv2;
                break;
            case LSH:
                rv1 <<= rv2;
                break;
            case LSH | UNSMARK:
                rv1 = (unsigned long) rv1 << rv2;
                break;
            case RSH:
                rv1 >>= rv2;
                break;
            case RSH | UNSMARK:
                rv1 = (unsigned long) rv1 >> rv2;
                break;
            case LAND:
                rtype = UND;
                if (v1.type == UND)
                    break;
                if (rv1 != 0)
                {
                    if (v2.type == UND)
                        break;
                    rv1 = rv2 != 0;
                }
                else
                    rv1 = 0;
                rtype = SGN;
                break;
            case LOR:
                rtype = UND;
                if (v1.type == UND)
                    break;
                if (rv1 == 0)
                {
                    if (v2.type == UND)
                        break;
                    rv1 = rv2 != 0;
                }
                else
                    rv1 = 1;
                rtype = SGN;
                break;
            case AND:
                rv1 &= rv2;
                break;
            case STAR:
                rv1 *= rv2;
                break;
            case PLUS:
                rv1 += rv2;
                break;
            case MINUS:
                rv1 -= rv2;
                break;
            case UMINUS:
                if (v1.type == UND)
                    rtype = UND;
                rv1 = -rv1;
                break;
            case OR:
                rv1 |= rv2;
                break;
            case CIRC:
                rv1 ^= rv2;
                break;
            case TILDE:
                rv1 = ~rv1;
                break;
            case NOT:
                rv1 = !rv1;
                if (rtype != UND)
                    rtype = SGN;
                break;
            case SLASH:
                if (rv2 == 0)
                {
                    rtype = UND;
                    break;
                }
                if (rtype == UNS)
                    rv1 /= (unsigned long) rv2;
                else
                    rv1 /= rv2;
                break;
            case PCT:
                if (rv2 == 0)
                {
                    rtype = UND;
                    break;
                }
                if (rtype == UNS)
                    rv1 %= (unsigned long) rv2;
                else
                    rv1 %= rv2;
                break;
            case COLON:
                if (op[-1] != QUEST)
                    error(ERROR, "Bad ?: in #if/endif");
                else
                {
                    op--;
                    if ((--vp)->val == 0)
                        v1 = v2;
                    rtype = v1.type;
                    rv1 = v1.val;
                }
                break;

            case DEFINED:
            case ARCHITECTURE:
                break;

            default:
                error(ERROR, "Eval botch (unknown operator)");
                return 1;
        }
/*lint +e574 +e644 */
        v1.val = rv1;
        v1.type = rtype;
        *vp++ = v1;
    }
    return 0;
}

struct value
    tokval(Token * tp)
{
    struct value v;
    Nlist *np;
    int i, base;
    unsigned int n;
    uchar *p, c;

    v.type = SGN;
    v.val = 0;
    switch (tp->type)
    {

        case NAME:
            v.val = 0;
            break;

        case NAME1:
            np = lookup(tp, 0);
            if (np != NULL && np->flag & (ISDEFINED | ISMAC))
                v.val = 1;
            break;

        case NAME2:
            np = lookup(tp, 0);
            if (np != NULL && np->flag & (ISARCHITECTURE))
                v.val = 1;
            break;

        case NUMBER:
            n = 0;
            base = 10;
            p = tp->t;
            c = p[tp->len];
            p[tp->len] = '\0';
            if (*p == '0')
            {
                base = 8;
                if (p[1] == 'x' || p[1] == 'X')
                {
                    base = 16;
                    p++;
                }
                p++;
            }
            for (;; p++)
            {
                if ((i = digit(*p)) < 0)
                    break;
                if (i >= base)
                    error(WARNING,
                          "Bad digit in number %t", tp);
                n *= base;
                n += i;
            }
            if (n >= 0x80000000 && base != 10)
                v.type = UNS;
            for (; *p; p++)
            {
                if (*p == 'u' || *p == 'U')
                    v.type = UNS;
                else
                    if (*p == 'l' || *p == 'L')
                        ;
                    else
                    {
                        error(ERROR,
                              "Bad number %t in #if/#elif", tp);
                        break;
                    }
            }
            v.val = n;
            tp->t[tp->len] = c;
            break;

        case CCON:
            n = 0;
            p = tp->t;
            if (*p == 'L')
            {
                p += 1;
                error(WARNING, "Wide char constant value undefined");
            }
            p += 1;
            if (*p == '\\')
            {
                p += 1;
                i = digit(*p);
                if (i >= 0 && i <= 7)
                {
                    n = i;
                    p += 1;
                    i = digit(*p);
                    if (i >= 0 && i <= 7)
                    {
                        p += 1;
                        n <<= 3;
                        n += i;
                        i = digit(*p);
                        if (i >= 0 && i <= 7)
                        {
                            p += 1;
                            n <<= 3;
                            n += i;
                        }
                    }
                }
                else
                    if (*p == 'x')
                    {
                        p += 1;
                        while (1)
                        {
                            i = digit(*p);
                            if (i < 0 || i > 16)
                                break;
                            p += 1;
                            n <<= 4;
                            n += i;
                        }
                    }
                    else
                    {
                        static const char cvcon[] = "b\bf\fn\nr\rt\tv\v''\"\"??\\\\";
                        static size_t cvlen = sizeof(cvcon) - 1;

                        size_t j;
                        for (j = 0; j < cvlen; j += 2)
                        {
                            if (*p == cvcon[j])
                            {
                                n = cvcon[j + 1];
                                break;
                            }
                        }
                        p += 1;
                        if (j >= cvlen)
                            error(WARNING,
                               "Undefined escape in character constant");
                    }
            }
            else
                if (*p == '\'')
                    error(ERROR, "Empty character constant");
                else
                    n = *p++;
            if (*p != '\'')
                error(WARNING, "Multibyte character constant undefined");
            else
                if (n > 127)
                    error(WARNING, "Character constant taken as not signed");
            v.val = n;
            break;

        case STRING:
            error(ERROR, "String in #if/#elif");
            break;
    }
    return v;
}

int
    digit(int i)
{
    if ('0' <= i && i <= '9')
        i -= '0';
    else
        if ('a' <= i && i <= 'f')
            i -= 'a' - 10;
        else
            if ('A' <= i && i <= 'F')
                i -= 'A' - 10;
            else
                i = -1;
    return i;
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

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