/* -*- 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 <stdio.h>
#include <ctype.h>
#include "cppdef.h"
#include "cpp.h"

/*
 * Generate (by hand-inspection) a set of unique values for each control
 * operator.  Note that this is not guaranteed to work for non-Ascii
 * machines.  CPP won't compile if there are hash conflicts.
 */

#define L_assert        ('a' + ('s' << 1))
#define L_define        ('d' + ('f' << 1))
#define L_elif          ('e' + ('i' << 1))
#define L_else          ('e' + ('s' << 1))
#define L_endif         ('e' + ('d' << 1))
#define L_if            ('i' + (EOS << 1))
#define L_ifdef         ('i' + ('d' << 1))
#define L_ifndef        ('i' + ('n' << 1))
#define L_include       ('i' + ('c' << 1))
#define L_line          ('l' + ('n' << 1))
#define L_nogood        (EOS + (EOS << 1))      /* To catch #i          */
#define L_pragma        ('p' + ('a' << 1))
#define L_undef         ('u' + ('d' << 1))
#define L_error         ('e' + ('r' << 1))      /* BP 5.3.92, #error */
#if OSL_DEBUG_LEVEL > 1
#define L_debug         ('d' + ('b' << 1))      /* #debug               */
#define L_nodebug       ('n' + ('d' << 1))      /* #nodebug             */
#endif


/*
 * Process #control lines.  Simple commands are processed inline,
 * while complex commands have their own subroutines.
 *
 * The counter is used to force out a newline before #line, and
 * #pragma commands.  This prevents these commands from ending up at
 * the end of the previous line if cpp is invoked with the -C option.
 */
int control(int counter)
{
    int c;
    char* tp;
    int hash;
    char* ep;

    c = skipws();
    if (c == '\n' || c == EOF_CHAR)
        return counter + 1;
    if (!isdigit(c))
        scanid(c);                  /* Get #word to token[]         */
    else
    {
        unget();                    /* Hack -- allow #123 as a      */
        strcpy(token, "line");      /* synonym for #line 123        */
    }
    hash = (token[1] == EOS) ? L_nogood : (token[0] + (token[2] << 1));
    switch (hash)
    {
    case L_assert:  tp = "assert";          break;
    case L_define:  tp = "define";          break;
    case L_elif:    tp = "elif";            break;
    case L_else:    tp = "else";            break;
    case L_endif:   tp = "endif";           break;
    case L_if:      tp = "if";              break;
    case L_ifdef:   tp = "ifdef";           break;
    case L_ifndef:  tp = "ifndef";          break;
    case L_include: tp = "include";         break;
    case L_line:    tp = "line";            break;
    case L_pragma:  tp = "pragma";          break;
    case L_undef:   tp = "undef";           break;
    case L_error:   tp = "error";           break;
#if OSL_DEBUG_LEVEL > 1
    case L_debug:   tp = "debug";           break;
    case L_nodebug: tp = "nodebug";         break;
#endif
    default:        hash = L_nogood;
        /*fall-through*/
    case L_nogood:  tp = "";                break;
    }
    if (!streq(tp, token))
        hash = L_nogood;
    /*
     * hash is set to a unique value corresponding to the
     * control keyword (or L_nogood if we think it's nonsense).
     */
    if (infile->fp == NULL)
        cwarn("Control line \"%s\" within macro expansion", token);
    if (!compiling)
    {                       /* Not compiling now    */
        switch (hash)
        {
        case L_if:                          /* These can't turn     */
        case L_ifdef:                       /*  compilation on, but */
        case L_ifndef:                      /*   we must nest #if's */
            if (++ifptr >= &ifstack[BLK_NEST])
                goto if_nest_err;
            *ifptr = 0;                     /* !WAS_COMPILING       */
        case L_line:                        /* Many                 */
            /*
             * Are pragma's always processed?
             */
        case L_pragma:                      /*  options             */
        case L_include:                     /*   are uninteresting  */
        case L_define:                      /*    if we             */
        case L_undef:                       /*     aren't           */
        case L_assert:                      /*      compiling.      */
        case L_error:                       /* BP 5.3.92, #error */
        dump_line:      skipnl();                       /* Ignore rest of line  */
            return counter + 1;
        }
    }
    /*
     * Make sure that #line and #pragma are output on a fresh line.
     */
    if (counter > 0 && (hash == L_line || hash == L_pragma))
    {
        PUTCHAR('\n');
        counter--;
    }

    switch (hash)
    {
    case L_line:
        /*
         * Parse the line to update the line number and "progname"
         * field and line number for the next input line.
         * Set wrongline to force it out later.
         */
        c = skipws();
        workp = work;                       /* Save name in work    */
        while (c != '\n' && c != EOF_CHAR)
        {
            save(c);
            c = get();
        }
        unget();
        save(EOS);
        /*
         * Split #line argument into <line-number> and <name>
         * We subtract 1 as we want the number of the next line.
         */
        line = atoi(work) - 1;              /* Reset line number    */
        for (tp = work; isdigit(*tp) || type[(int)*tp] == SPA; tp++)
            ;                               /* Skip over digits     */
        if (*tp != EOS)                     /* Got a filename, so:  */
        {
            if (*tp == '"' && (ep = strrchr(tp + 1, '"')) != NULL)
            {
                tp++;                       /* Skip over left quote */
                *ep = EOS;                  /* And ignore right one */
            }
            if (infile->progname != NULL)   /* Give up the old name */
                free(infile->progname);     /* if it's allocated.   */
            infile->progname = savestring(tp);
        }
        wrongline = TRUE;                   /* Force output later   */
        break;

    case L_include:
        doinclude();
        break;

    case L_define:
        dodefine();
        break;

    case L_undef:
        doundef();
        break;

    case L_else:
        if (ifptr == &ifstack[0])
            goto nest_err;
        else if ((*ifptr & ELSE_SEEN) != 0)
            goto else_seen_err;
        *ifptr |= ELSE_SEEN;
        if ((*ifptr & WAS_COMPILING) != 0)
        {
            if (compiling || (*ifptr & TRUE_SEEN) != 0)
                compiling = FALSE;
            else
            {
                compiling = TRUE;
            }
        }
        break;

    case L_elif:
        if (ifptr == &ifstack[0])
            goto nest_err;
        else if ((*ifptr & ELSE_SEEN) != 0)
        {
          else_seen_err:  cerror("#%s may not follow #else", token);
            goto dump_line;
        }
        if ((*ifptr & (WAS_COMPILING | TRUE_SEEN)) != WAS_COMPILING)
        {
            compiling = FALSE;              /* Done compiling stuff */
            goto dump_line;                 /* Skip this clause     */
        }
        doif(L_if);
        break;

    case L_if:
    case L_ifdef:
    case L_ifndef:
        if (++ifptr >= &ifstack[BLK_NEST])
          if_nest_err:    cfatal("Too many nested #%s statements", token);
        *ifptr = WAS_COMPILING;
        doif(hash);
        break;

    case L_endif:
        if (ifptr == &ifstack[0])
        {
          nest_err:       cerror("#%s must be in an #if", token);
            goto dump_line;
        }
        if (!compiling && (*ifptr & WAS_COMPILING) != 0)
            wrongline = TRUE;
        compiling = ((*ifptr & WAS_COMPILING) != 0);
        --ifptr;
        break;

    case L_assert:
        if (eval() == 0)
            cerror("Preprocessor assertion failure", NULLST);
        break;

    case L_pragma:
        /*
         * #pragma is provided to pass "options" to later
         * passes of the compiler.  cpp doesn't have any yet.
         */
        fprintf( pCppOut, "#pragma ");
        while ((c = get()) != '\n' && c != EOF_CHAR)
            cput(c);
        unget();
        break;

#if OSL_DEBUG_LEVEL > 1
    case L_debug:
        if (debug == 0)
            dumpdef("debug set on");
        debug++;
        break;

    case L_nodebug:
        debug--;
        break;
#endif
    case L_error:                       /* BP 5.3.92, #error */
        fprintf( pCppOut, "cpp: line %d, Error directive: ", line );
        while ((c = get()) != '\n' && c != EOF_CHAR)
            cput(c);
        fprintf( pCppOut, "\n" );
        exit( 1 );

    default:
        /*
         * Undefined #control keyword.
         * Note: the correct behavior may be to warn and
         * pass the line to a subsequent compiler pass.
         * This would allow #asm or similar extensions.
         */
        cerror("Illegal # command \"%s\"", token);
        break;
    }
    if (hash != L_include)
    {
        if (skipws() != '\n')
        {
            cwarn("Unexpected text in #control line ignored", NULLST);
            skipnl();
        }
    }
    return counter + 1;
}

/*
 * Process an #if, #ifdef, or #ifndef.  The latter two are straightforward,
 * while #if needs a subroutine of its own to evaluate the expression.
 *
 * doif() is called only if compiling is TRUE.  If false, compilation
 * is always suppressed, so we don't need to evaluate anything.  This
 * suppresses unnecessary warnings.
 */
FILE_LOCAL void doif(int hash)
{
    int c;
    int found;

    if ((c = skipws()) == '\n' || c == EOF_CHAR)
    {
        unget();
        goto badif;
    }
    if (hash == L_if)
    {
        unget();
        found = (eval() != 0);      /* Evaluate expr, != 0 is  TRUE */
        hash = L_ifdef;             /* #if is now like #ifdef       */
    }
    else
    {
        if (type[c] != LET)         /* Next non-blank isn't letter  */
            goto badif;             /* ... is an error              */
        found = (lookid(c) != NULL); /* Look for it in symbol table */
    }
    if (found == (hash == L_ifdef))
    {
        compiling = TRUE;
        *ifptr |= TRUE_SEEN;
    }
    else
    {
        compiling = FALSE;
    }
    return;

  badif:  cerror("#if, #ifdef, or #ifndef without an argument", NULLST);
    skipnl();                               /* Prevent an extra     */
    unget();                                /* Error message        */
    return;
}

/*
 * Process the #include control line.
 * There are three variations:
 *      #include "file"         search somewhere relative to the
 *                              current source file, if not found,
 *                              treat as #include <file>.
 *      #include <file>         Search in an implementation-dependent
 *                              list of places.
 *      #include token          Expand the token, it must be one of
 *                              "file" or <file>, process as such.
 *
 * Note: the November 12 draft forbids '>' in the #include <file> format.
 * This restriction is unnecessary and not implemented.
 */
FILE_LOCAL void doinclude()
{
    int c;
    int delim;

    delim = macroid(skipws());
    if (delim != '<' && delim != '"')
        goto incerr;
    if (delim == '<')
        delim = '>';
    workp = work;
    instring = TRUE;                /* Accept all characters        */
#ifdef CONTROL_COMMENTS_NOT_ALLOWED
    while ((c = get()) != '\n' && c != EOF_CHAR)
        save(c);                    /* Put it away.                 */
    unget();                        /* Force nl after includee      */
    /*
     * The draft is unclear if the following should be done.
     */
    while (--workp >= work && *workp == ' ')
        ;                           /* Trim blanks from filename    */
    if (*workp != delim)
        goto incerr;
#else
    while ((c = get()) != delim && c != EOF_CHAR)
        save(c);
#endif
    *workp = EOS;                   /* Terminate filename           */
    instring = FALSE;
    if (openinclude(work, (delim == '"')))
        return;
    /*
     * No sense continuing if #include file isn't there.
     */
    cfatal("Cannot open include file \"%s\"", work);

  incerr: cerror("#include syntax error", NULLST);
    return;
}

/*
 * Actually open an include file.  This routine is only called from
 * doinclude() above, but was written as a separate subroutine for
 * programmer convenience.  It searches the list of directories
 * and actually opens the file, linking it into the list of
 * active files.  Returns TRUE if the file was opened, FALSE
 * if openinclude() fails.  No error message is printed.
 */
FILE_LOCAL int openinclude(char* filename, int searchlocal)
{
    char** incptr;
    char tmpname[NFWORK]; /* Filename work area   */

    if (searchlocal)
    {
        /*
         * Look in local directory first
         */
#if HOST == SYS_UNIX
        /*
         * Try to open filename relative to the directory of the current
         * source file (as opposed to the current directory). (ARF, SCK).
         */
        if (filename[0] != '/' &&
            hasdirectory(infile->filename, tmpname, NFWORK))
        {
            int len = strlen(tmpname);
            int len2 = strlen(filename);
            if(len + len2 < NFWORK)
            {
                memcpy(tmpname + len, filename, len2);
                tmpname[len + len2] = 0;
            }
            else
            {
                cfatal("Filename work buffer overflow", NULLST);
            }
        }
        else
        {
            int len = strlen(filename);
            if(len < NFWORK)
            {
                memcpy(tmpname, filename, len);
                tmpname[len] = 0;
            }
            else
            {
                cfatal("Filename work buffer overflow", NULLST);
            }
        }
#else
        if (!hasdirectory(filename, tmpname, NFWORK) &&
            hasdirectory(infile->filename, tmpname, NFWORK))
        {
            strcat(tmpname, filename);
        }
        else
        {
            strcpy(tmpname, filename);
        }
#endif
        if (openfile(tmpname))
            return TRUE;
    }
    /*
     * Look in any directories specified by -I command line
     * arguments, then in the builtin search list.
     */
    for (incptr = incdir; incptr < incend; incptr++)
    {
        if (strlen(*incptr) + strlen(filename) >= (NFWORK - 1))
            cfatal("Filename work buffer overflow", NULLST);
        else
        {
#if HOST == SYS_UNIX
            if (filename[0] == '/')
                strcpy(tmpname, filename);
            else
                sprintf(tmpname, "%s/%s", *incptr, filename);

#elif HOST == SYS_UNKNOWN
            if (filename[0] == '\\')
                strcpy(tmpname, filename);
            else
                sprintf(tmpname, "%s\\%s", *incptr, filename);
#else
            if (!hasdirectory(filename, tmpname, NFWORK))
                sprintf(tmpname, "%s%s", *incptr, filename);
#endif
            if (openfile(tmpname))
                return TRUE;
        }
    }
    return FALSE;
}

/*
 * If a device or directory is found in the source filename string, the
 * node/device/directory part of the string is copied to result and
 * hasdirectory returns TRUE.  Else, nothing is copied and it returns FALSE.
 */
FILE_LOCAL int hasdirectory(char* source, char* result, int max)
{
#if HOST == SYS_UNIX
    char* tp;

    if ((tp = strrchr(source, '/')) == NULL)
        return FALSE;
    else
    {
        int len = (int)(tp - source);
        if(len < max)
        {
            memcpy(result, source, len);
            result[len] = 0;
        }
        else
        {
            cfatal("Filename work buffer overflow", NULLST);
        }
        return TRUE;
    }
#else
    /*
     * Random DEC operating system (RSTS/E)
     */
    char* tp;

    (void)max;

    if ((tp = strrchr(source, ']')) == NULL &&
        (tp = strrchr(source, ':')) == NULL)
    {
        return FALSE;
    }
    else
    {
        strncpy(result, source, tp - source + 1);
        result[tp - source + 1] = EOS;
        return TRUE;
    }
#endif
}

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