/*

Copyright (c) 1993, 1994, 1998 The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.

*/

#include "def.h"

static int deftype(char *line, struct filepointer *filep,
                   struct inclist *file_red, struct inclist *file,
                   int parse_it);
static int zero_value(char *filename, char *exp, struct filepointer *filep,
                      struct inclist *file_red);
static struct symtab **slookup(const char *symbol, struct inclist *file);
static boolean merge2defines(struct inclist *file1, struct inclist *file2);

static const char *const directives[] = {
    "if",
    "ifdef",
    "ifndef",
    "else",
    "endif",
    "define",
    "undef",
    "include",
    "line",
    "pragma",
    "error",
    "ident",
    "sccs",
    "elif",
    "eject",
    "warning",
    "include_next",
    NULL
};

static int
gobble(struct filepointer *filep, struct inclist *file,
       struct inclist *file_red)
{
    char *line;

    while ((line = getnextline(filep))) {
        int   type = deftype(line, filep, file_red, file, FALSE);

        switch (type) {
        case IF:
        case IFFALSE:
        case IFGUESSFALSE:
        case IFDEF:
        case IFNDEF:
            type = gobble(filep, file, file_red);
            while ((type == ELIF) || (type == ELIFFALSE) ||
                   (type == ELIFGUESSFALSE))
                type = gobble(filep, file, file_red);
            if (type == ELSE)
                (void) gobble(filep, file, file_red);
            break;
        case ELSE:
        case ENDIF:
            debug(0, ("%s, line %d: #%s\n",
                      file->i_file, filep->f_line, directives[type]));
            return (type);
        case DEFINE:
        case UNDEF:
        case INCLUDE:
        case INCLUDEDOT:
        case PRAGMA:
        case ERROR:
        case IDENT:
        case SCCS:
        case EJECT:
        case WARNING:
        case INCLUDENEXT:
        case INCLUDENEXTDOT:
            break;
        case ELIF:
        case ELIFFALSE:
        case ELIFGUESSFALSE:
            return (type);
        case -1:
            warning("%s", file_red->i_file);
            if (file_red != file)
                warning1(" (reading %s)", file->i_file);
            warning1(", line %ld: unknown directive == \"%s\"\n",
                     filep->f_line, line);
            break;
        }
    }
    return (-1);
}

/*
 * Decide what type of # directive this line is.
 */
static int
deftype(char *line, struct filepointer *filep,
        struct inclist *file_red, struct inclist *file, int parse_it)
{
    char *p;
    char *directive, savechar, *q;
    int   ret;

    /*
     * Parse the directive...
     */
    directive = line + 1;
    while (*directive == ' ' || *directive == '\t')
        directive++;

    p = directive;
    while ((*p == '_') || (*p >= 'a' && *p <= 'z'))
        p++;
    savechar = *p;
    *p = '\0';
    ret = match(directive, directives);
    *p = savechar;

    /* If we don't recognize this compiler directive or we happen to just
     * be gobbling up text while waiting for an #endif or #elif or #else
     * in the case of an #elif we must check the zero_value and return an
     * ELIF or an ELIFFALSE.
     */

    if (ret == ELIF && !parse_it) {
        while (*p == ' ' || *p == '\t')
            p++;
        /*
         * parse an expression.
         */
        debug(0, ("%s, line %d: #elif %s ", file->i_file, filep->f_line, p));
        ret = zero_value(file->i_file, p, filep, file_red);
        if (ret != IF) {
            debug(0, ("false...\n"));
            if (ret == IFFALSE)
                return (ELIFFALSE);
            else
                return (ELIFGUESSFALSE);
        }
        else {
            debug(0, ("true...\n"));
            return (ELIF);
        }
    }

    if (ret < 0 || !parse_it)
        return (ret);

    /*
     * now decide how to parse the directive, and do it.
     */
    while (*p == ' ' || *p == '\t')
        p++;
    q = p + strlen(p);
    do {
        q--;
    } while (*q == ' ' || *q == '\t');
    q[1] = '\0';
    switch (ret) {
    case IF:
        /*
         * parse an expression.
         */
        ret = zero_value(file->i_file, p, filep, file_red);
        debug(0, ("%s, line %d: %s #if %s\n",
                  file->i_file, filep->f_line, ret ? "false" : "true", p));
        break;
    case IFDEF:
    case IFNDEF:
        debug(0, ("%s, line %d: #%s %s\n",
                  file->i_file, filep->f_line, directives[ret], p));
    case UNDEF:
        /*
         * separate the name of a single symbol.
         */
        while (isalnum(*p) || *p == '_')
            *line++ = *p++;
        *line = '\0';
        break;
    case INCLUDE:
    case INCLUDENEXT:
        debug(2, ("%s, line %d: #include%s %s\n",
                  file->i_file, filep->f_line,
                  (ret == INCLUDE) ? "" : "_next", p));

        /* Support ANSI macro substitution */
        while (1) {
            struct symtab **sym;

            if (!*p || *p == '"' || *p == '<')
                break;

            sym = isdefined(p, file_red, NULL);
            if (!sym)
                break;

            p = (*sym)->s_value;
            debug(3, ("%s : #includes SYMBOL %s = %s\n",
                      file->i_incstring, (*sym)->s_name, (*sym)->s_value));
            /* mark file as having included a 'soft include' */
            file->i_flags |= INCLUDED_SYM;
        }

        /*
         * Separate the name of the include file.
         */
        while (*p && *p != '"' && *p != '<')
            p++;
        if (!*p)
            return (-2);
        if (*p++ == '"') {
            if (ret == INCLUDE)
                ret = INCLUDEDOT;
            else
                ret = INCLUDENEXTDOT;
            while (*p && *p != '"')
                *line++ = *p++;
        }
        else
            while (*p && *p != '>')
                *line++ = *p++;
        *line = '\0';
        break;
    case DEFINE:
        /*
         * copy the definition back to the beginning of the line.
         */
        memmove(line, p, strlen(p) + 1);
        break;
    case ELSE:
    case ENDIF:
    case ELIF:
    case PRAGMA:
    case ERROR:
    case IDENT:
    case SCCS:
    case EJECT:
    case WARNING:
        debug(0, ("%s, line %d: #%s\n",
                  file->i_file, filep->f_line, directives[ret]));
        /*
         * nothing to do.
         */
        break;
    }
    return (ret);
}

static struct symtab **
fdefined(const char *symbol, struct inclist *file, struct inclist **srcfile)
{
    struct symtab **val;
    static int      recurse_lvl = 0;

    if (file->i_flags & DEFCHECKED)
        return (NULL);
    debug(2, ("Looking for %s in %s\n", symbol, file->i_file));
    file->i_flags |= DEFCHECKED;
    if ((val = slookup(symbol, file)))
        debug(1, ("%s defined in %s as %s\n",
                  symbol, file->i_file, (*val)->s_value));
    if (val == NULL && file->i_list) {
        struct inclist **ip;
        unsigned int     i;

        for (ip = file->i_list, i = 0; i < file->i_listlen; i++, ip++) {
            if (file->i_merged[i] == FALSE) {
                val = fdefined(symbol, *ip, srcfile);
                file->i_merged[i] = merge2defines(file, *ip);
                if (val != NULL)
                    break;
            }
        }
    }
    else if (val != NULL && srcfile != NULL)
        *srcfile = file;
    recurse_lvl--;
    file->i_flags &= ~DEFCHECKED;

    return (val);
}

struct symtab **
isdefined(const char *symbol, struct inclist *file, struct inclist **srcfile)
{
    struct symtab **val;

    if ((val = slookup(symbol, &maininclist))) {
        debug(1, ("%s defined on command line\n", symbol));
        if (srcfile != NULL)
            *srcfile = &maininclist;
        return (val);
    }
    if ((val = fdefined(symbol, file, srcfile)))
        return (val);
    debug(1, ("%s not defined in %s\n", symbol, file->i_file));
    return (NULL);
}

/*
 * Return type based on if the #if expression evaluates to 0
 */
static int
zero_value(char *filename, char *exp,
           struct filepointer *filep, struct inclist *file_red)
{
    if (cppsetup(filename, exp, filep, file_red))
        return (IFFALSE);
    else
        return (IF);
}

void
define2(const char *name, const char *val, struct inclist *file)
{
    int first, last, below;
    struct symtab **sp = NULL, **dest;
    struct symtab *stab;

    /* Make space if it's needed */
    if (file->i_defs == NULL) {
        file->i_defs = mallocarray(SYMTABINC, sizeof(struct symtab *));
        file->i_ndefs = 0;
    }
    else if (!(file->i_ndefs % SYMTABINC))
        file->i_defs = reallocarray(file->i_defs, (file->i_ndefs + SYMTABINC),
                                    sizeof(struct symtab *));

    if (file->i_defs == NULL)
        fatalerr("malloc()/realloc() failure in insert_defn()\n");

    below = first = 0;
    last = file->i_ndefs - 1;
    while (last >= first) {
        /* Fast inline binary search */
        const char *s1;
        const char *s2;
        int middle = (first + last) / 2;

        /* Fast inline strcmp() */
        s1 = name;
        s2 = file->i_defs[middle]->s_name;
        while (*s1++ == *s2++)
            if (s2[-1] == '\0')
                break;

        /* If exact match, set sp and break */
        if (*--s1 == *--s2) {
            sp = file->i_defs + middle;
            break;
        }

        /* If name > i_defs[middle] ... */
        if (*s1 > *s2) {
            below = first;
            first = middle + 1;
        }
        /* else ... */
        else {
            below = last = middle - 1;
        }
    }

    /* Search is done.  If we found an exact match to the symbol name,
       just replace its s_value */
    if (sp != NULL) {
        debug(1, ("redefining %s from %s to %s in file %s\n",
                  name, (*sp)->s_value, val, file->i_file));
        free((*sp)->s_value);
        (*sp)->s_value = strdup(val);
        if ((*sp)->s_value == NULL)
            fatalerr("strdup() failure in %s()\n", __func__);
        return;
    }

    sp = file->i_defs + file->i_ndefs++;
    dest = file->i_defs + below + 1;
    while (sp > dest) {
        *sp = sp[-1];
        sp--;
    }
    stab = malloc(sizeof(struct symtab));
    if (stab == NULL)
        fatalerr("malloc()/realloc() failure in insert_defn()\n");

    debug(1, ("defining %s to %s in file %s\n", name, val, file->i_file));
    stab->s_name = strdup(name);
    stab->s_value = strdup(val);
    if ((stab->s_name == NULL) || (stab->s_value == NULL))
        fatalerr("strdup() failure in %s()\n", __func__);
    *sp = stab;
}

void
define(char *def, struct inclist *file)
{
    char *val;

    /* Separate symbol name and its value */
    val = def;
    while (isalnum(*val) || *val == '_')
        val++;
    if (*val)
        *val++ = '\0';
    while (*val == ' ' || *val == '\t')
        val++;

    if (!*val)
        define2(def, "1", file);
    else
        define2(def, val, file);
}

struct symtab **
slookup(const char *symbol, struct inclist *file)
{
    int first = 0;
    int last;

    if (file == NULL)
        return NULL;

    last = file->i_ndefs - 1;

    while (last >= first) {
        /* Fast inline binary search */
        const char *s1;
        const char *s2;
        int middle = (first + last) / 2;

        /* Fast inline strcmp() */
        s1 = symbol;
        s2 = file->i_defs[middle]->s_name;
        while (*s1++ == *s2++)
            if (s2[-1] == '\0')
                break;

        /* If exact match, we're done */
        if (*--s1 == *--s2) {
            return file->i_defs + middle;
        }

        /* If symbol > i_defs[middle] ... */
        if (*s1 > *s2) {
            first = middle + 1;
        }
        /* else ... */
        else {
            last = middle - 1;
        }
    }
    return (NULL);
}

static boolean
merge2defines(struct inclist *file1, struct inclist *file2)
{
    if ((file1 == NULL) || (file2 == NULL) || !(file2->i_flags & FINISHED))
        return 0;

    for (unsigned int i = 0; i < file2->i_listlen; i++)
        if (file2->i_merged[i] == FALSE)
            return 0;

    {
        int first1 = 0;
        int last1 = file1->i_ndefs - 1;

        int first2 = 0;
        int last2 = file2->i_ndefs - 1;

        int first = 0;
        struct symtab **i_defs = NULL;
        int deflen = file1->i_ndefs + file2->i_ndefs;

        debug(2, ("merging %s into %s\n", file2->i_file, file1->i_file));

        if (deflen > 0) {
            /* make sure deflen % SYMTABINC == 0 is still true */
            deflen += (SYMTABINC - deflen % SYMTABINC) % SYMTABINC;
            i_defs = mallocarray(deflen, sizeof(struct symtab *));
            if (i_defs == NULL)
                return 0;
        }

        while ((last1 >= first1) && (last2 >= first2)) {
            const char *s1 = file1->i_defs[first1]->s_name;
            const char *s2 = file2->i_defs[first2]->s_name;

            if (strcmp(s1, s2) < 0)
                i_defs[first++] = file1->i_defs[first1++];
            else if (strcmp(s1, s2) > 0)
                i_defs[first++] = file2->i_defs[first2++];
            else {              /* equal */
                i_defs[first++] = file2->i_defs[first2++];
                first1++;
            }
        }
        while (last1 >= first1) {
            i_defs[first++] = file1->i_defs[first1++];
        }
        while (last2 >= first2) {
            i_defs[first++] = file2->i_defs[first2++];
        }

        if (file1->i_defs)
            free(file1->i_defs);
        file1->i_defs = i_defs;
        file1->i_ndefs = first;

        return 1;
    }
}

void
undefine(const char *symbol, struct inclist *file)
{
    struct symtab **ptr;
    struct inclist *srcfile;

    while ((ptr = isdefined(symbol, file, &srcfile)) != NULL) {
        srcfile->i_ndefs--;
        for (; ptr < srcfile->i_defs + srcfile->i_ndefs; ptr++)
            *ptr = ptr[1];
    }
}

int
find_includes(struct filepointer *filep, struct inclist *file,
              struct inclist *file_red, int recursion, boolean failOK)
{
    char *line;

    while ((line = getnextline(filep))) {
        int type = deftype(line, filep, file_red, file, TRUE);

        switch (type) {
        case IF:
 doif:
            type = find_includes(filep, file, file_red, recursion + 1, failOK);
            while ((type == ELIF) || (type == ELIFFALSE) ||
                   (type == ELIFGUESSFALSE))
                type = gobble(filep, file, file_red);
            if (type == ELSE)
                gobble(filep, file, file_red);
            break;
        case IFFALSE:
        case IFGUESSFALSE:
 doiffalse:
        {
            boolean recfailOK;

            if (type == IFGUESSFALSE || type == ELIFGUESSFALSE)
                recfailOK = TRUE;
            else
                recfailOK = failOK;
            type = gobble(filep, file, file_red);
            if (type == ELSE)
                find_includes(filep, file, file_red, recursion + 1, recfailOK);
            else if (type == ELIF)
                goto doif;
            else if ((type == ELIFFALSE) || (type == ELIFGUESSFALSE))
                goto doiffalse;
        }
            break;
        case IFDEF:
        case IFNDEF:
            if ((type == IFDEF && isdefined(line, file_red, NULL))
                || (type == IFNDEF && !isdefined(line, file_red, NULL))) {
                debug(1, (type == IFNDEF ?
                          "line %d: %s !def'd in %s via %s%s\n" : "",
                          filep->f_line, line,
                          file->i_file, file_red->i_file, ": doit"));
                type = find_includes(filep, file,
                                     file_red, recursion + 1, failOK);
                while (type == ELIF || type == ELIFFALSE ||
                       type == ELIFGUESSFALSE)
                    type = gobble(filep, file, file_red);
                if (type == ELSE)
                    gobble(filep, file, file_red);
            }
            else {
                debug(1, (type == IFDEF ?
                          "line %d: %s !def'd in %s via %s%s\n" : "",
                          filep->f_line, line,
                          file->i_file, file_red->i_file, ": gobble"));
                type = gobble(filep, file, file_red);
                if (type == ELSE)
                    find_includes(filep, file, file_red, recursion + 1, failOK);
                else if (type == ELIF)
                    goto doif;
                else if (type == ELIFFALSE || type == ELIFGUESSFALSE)
                    goto doiffalse;
            }
            break;
        case ELSE:
        case ELIFFALSE:
        case ELIFGUESSFALSE:
        case ELIF:
            if (!recursion)
                gobble(filep, file, file_red);
        case ENDIF:
            if (recursion)
                return (type);
        case DEFINE:
            define(line, file);
            break;
        case UNDEF:
            if (!*line) {
                warning("%s", file_red->i_file);
                if (file_red != file)
                    warning1(" (reading %s)", file->i_file);
                warning1(", line %ld: incomplete undef == \"%s\"\n",
                         filep->f_line, line);
                break;
            }
            undefine(line, file_red);
            break;
        case INCLUDE:
        case INCLUDEDOT:
        case INCLUDENEXT:
        case INCLUDENEXTDOT:
        {
            struct inclist *inclist_save = inclistnext;
            const char **includedirs_save = includedirsnext;

            debug(2, ("%s, reading %s, includes %s\n",
                      file_red->i_file, file->i_file, line));
            add_include(filep, file, file_red, line, type, failOK);
            inclistnext = inclist_save;
            includedirsnext = includedirs_save;
        }
            break;
        case ERROR:
        case WARNING:
            warning("%s", file_red->i_file);
            if (file_red != file)
                warning1(" (reading %s)", file->i_file);
            warning1(", line %ld: %s\n", filep->f_line, line);
            break;

        case PRAGMA:
        case IDENT:
        case SCCS:
        case EJECT:
            break;
        case -1:
            warning("%s", file_red->i_file);
            if (file_red != file)
                warning1(" (reading %s)", file->i_file);
            warning1(", line %ld: unknown directive == \"%s\"\n",
                     filep->f_line, line);
            break;
        case -2:
            warning("%s", file_red->i_file);
            if (file_red != file)
                warning1(" (reading %s)", file->i_file);
            warning1(", line %ld: incomplete include == \"%s\"\n",
                     filep->f_line, line);
            break;
        }
    }
    file->i_flags |= FINISHED;
    debug(2, ("finished with %s\n", file->i_file));
    return (-1);
}