/* $Header: /p/tcsh/cvsroot/tcsh/gethost.c,v 1.15 2012/01/15 17:14:54 christos Exp $ */
/*
 * gethost.c: Create version file from prototype
 */
/*-
 * Copyright (c) 1980, 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include "sh.h"

RCSID("$tcsh: gethost.c,v 1.15 2012/01/15 17:14:54 christos Exp $")

#ifdef SCO
# define perror __perror
# define rename __rename
# define getopt __getopt
# define system __system
#endif
#include <stdio.h>
#ifdef SCO
# undef perror
# undef rename
# undef getopt
# undef system
#endif

#include <ctype.h>

#define ISSPACE(p)	(isspace((unsigned char) (p)) && (p) != '\n')

/* 
 * We cannot do that, because some compilers like #line and others
 * like # <lineno>
 * #define LINEDIRECTIVE 
 */

static const char *keyword[] =
{
    "vendor",
#define T_VENDOR	0
    "hosttype",
#define T_HOSTTYPE	1
    "machtype",
#define T_MACHTYPE	2
    "ostype",
#define T_OSTYPE	3
    "newdef",
#define T_NEWDEF	4
    "enddef",
#define T_ENDDEF	5
    "newcode",
#define T_NEWCODE	6
    "endcode",
#define T_ENDCODE	7
    "comment",
#define T_COMMENT	8
    "macro",
#define T_MACRO		9
    NULL
#define T_NONE		10
};

#define S_DISCARD	0
#define S_COMMENT	1
#define S_CODE		2
#define S_KEYWORD	3

static int findtoken (char *);
static char *gettoken (char **, char  *);
static char *pname;

int main (int, char *[]);

/* findtoken():
 *	Return the token number of the given token
 */
static int
findtoken(char *ptr)
{
    int i;

    if (ptr == NULL || *ptr == '\0')
	return T_NONE;

    for (i = 0; keyword[i] != NULL; i++)
	if (strcmp(keyword[i], ptr) == 0)
	    return i;

    return T_NONE;
}


/* gettoken():
 *	Get : delimited token and remove leading/trailing blanks/newlines
 */
static char *
gettoken(char **pptr, char *token)
{
    char *ptr = *pptr;
    char *tok = token;

    for (; *ptr && ISSPACE(*ptr); ptr++)
	continue;

    for (; *ptr && *ptr != ':'; *tok++ = *ptr++)
	continue;

    if (*ptr == ':')
	ptr++;
    else
	tok--;

    for (tok--; tok >= token && *tok && ISSPACE(*tok); tok--)
	continue;

    *++tok = '\0';

    *pptr = ptr;
    return token;
}

static char *
cat(const char *a, const char *b, size_t len)
{
	size_t l;
	char *r;

	if (len == 0)
		len = strlen(b);
	l = strlen(a) + len + 1;
	if ((r = malloc(l)) == NULL)
		abort();
	snprintf(r, l, "%s%.*s", a, (int)len, b);
	return r;
}

static const char *
explode(const char *defs)
{
	static const char def[] = "defined("; /* ) */
	static char *buf;
	size_t len;
	const char *ptr, *bptr, *eptr = NULL, *name;
	size_t buflen = 0;

	if (strstr(defs, "#machine(" /* ) */))
		return defs;

	free(buf);
	buf = strdup("("); /* ) */
	for (ptr = defs; (bptr = strstr(ptr, def)) != NULL; ptr = eptr + 1) {
		if (ptr != bptr)
			buf = cat(buf, ptr, bptr - ptr);
		if ((eptr = strchr(ptr + sizeof(def) - 1, ')')) == NULL) {
			(void) fprintf(stderr, "%s: missing close paren `%s'\n",
			    pname, defs);
			return defs;
		}
		buf = cat(buf, bptr, eptr - bptr + 1);
		name = bptr + sizeof(def) - 1;
		len = eptr - name;
		if (len < 1) {
			(void) fprintf(stderr, "%s: empty define `%s'\n",
			    pname, defs);
			return defs;
		}
		if (*name != '_') {
			char *undername = malloc(len + 10);
			buf = cat(buf, " || defined(", 0);
			snprintf(undername, len + 10, "__%.*s__)", (int)len,
			    name);
			buf = cat(buf, undername, len + 5);
			buf = cat(buf, " || defined(", 0);
			snprintf(undername, len + 10, "__%.*s)", (int)len,
			    name);
			buf = cat(buf, undername, len + 3);
		}
	}
	if (!eptr) {
	    (void) fprintf(stderr, "%s: invalid input `%s'\n", pname, defs);
	    return defs;
        }
	buf = cat(buf, eptr + 1, 0);
	buf = cat(buf, ")", 0);
	return buf;
}
	

int
main(int argc, char *argv[])
{
    char line[INBUFSIZE];
    const char *fname = "stdin";
    char *ptr, *tok;
    char defs[INBUFSIZE];
    char stmt[INBUFSIZE];
    FILE *fp = stdin;
    int lineno = 0;
    int inprocess = 0;
    int token, state;
    int errs = 0;

    if ((pname = strrchr(argv[0], '/')) == NULL)
	pname = argv[0];
    else
	pname++;

    if (argc > 2) {
	(void) fprintf(stderr, "Usage: %s [<filename>]\n", pname);
	return 1;
    }

    if (argc == 2)
	if ((fp = fopen(fname = argv[1], "r")) == NULL) {
	    (void) fprintf(stderr, "%s: Cannot open `%s'\n", pname, fname);
	    return 1;
	}

    state = S_DISCARD;

    while ((ptr = fgets(line, sizeof(line), fp)) != NULL) {
	lineno++;
	switch (token = findtoken(gettoken(&ptr, defs))) {
	case T_NEWCODE:
	    state = S_CODE;
	    break;

	case T_ENDCODE:
	    state = S_DISCARD;
	    break;

	case T_COMMENT:
	    state = S_COMMENT;
	    break;

	case T_NEWDEF:
	    state = S_KEYWORD;
	    break;

	case T_ENDDEF:
	    state = S_DISCARD;
	    break;

	case T_VENDOR:
	    state = S_KEYWORD;
	    break;

	case T_HOSTTYPE:
	    state = S_KEYWORD;
	    break;

	case T_MACHTYPE:
	    state = S_KEYWORD;
	    break;

	case T_OSTYPE:
	    state = S_KEYWORD;
	    break;

	case T_MACRO:
	    if (gettoken(&ptr, defs) == NULL) {
		(void) fprintf(stderr, "%s: \"%s\", %d: Missing macro name\n",
			       pname, fname, lineno);
		break;
	    }
	    if (gettoken(&ptr, stmt) == NULL) {
		(void) fprintf(stderr, "%s: \"%s\", %d: Missing macro body\n",
			       pname, fname, lineno);
		break;
	    }
	    (void) fprintf(stdout, "\n#if %s\n# define %s\n#endif\n\n", stmt,
			   defs);
	    break;

	case T_NONE:
	    if (state != S_CODE && *defs != '\0') {
		(void) fprintf(stderr, "%s: \"%s\", %d: Discarded\n",
			       pname, fname, lineno);
		if (++errs == 30) {
		    (void) fprintf(stderr, "%s: Too many errors\n", pname);
		    return 1;
		}
		break;
	    }
	    (void) fprintf(stdout, "%s", line);
	    break;

	default:
	    (void) fprintf(stderr, "%s: \"%s\", %d: Unexpected token\n",
			   pname, fname, lineno);
	    return 1;
	}

	switch (state) {
	case S_DISCARD:
	    if (inprocess) {
		inprocess = 0;
		(void) fprintf(stdout, "#endif\n");
	    }
	    break;

	case S_KEYWORD:
	    tok = gettoken(&ptr, defs);
	    if (token == T_NEWDEF) {
		if (inprocess) {
		    (void) fprintf(stderr, "%s: \"%s\", %d: Missing enddef\n",
				   pname, fname, lineno);
		    return 1;
		}
		if (tok == NULL) {
		    (void) fprintf(stderr, "%s: \"%s\", %d: No defs\n",
				   pname, fname, lineno);
		    return 1;
		}
		(void) fprintf(stdout, "\n\n");
#ifdef LINEDIRECTIVE
		(void) fprintf(stdout, "# %d \"%s\"\n", lineno + 1, fname);
#endif /* LINEDIRECTIVE */
		(void) fprintf(stdout, "#if %s\n", defs);
		inprocess = 1;
	    }
	    else {
		if (tok && *tok)
		    (void) fprintf(stdout, "# if (%s) && !defined(_%s_)\n",
				   explode(defs), keyword[token]);
		else
		    (void) fprintf(stdout, "# if !defined(_%s_)\n", 
				   keyword[token]);

		if (gettoken(&ptr, stmt) == NULL) {
		    (void) fprintf(stderr, "%s: \"%s\", %d: No statement\n",
				   pname, fname, lineno);
		    return 1;
		}
		(void) fprintf(stdout, "# define _%s_\n", keyword[token]);
		(void) fprintf(stdout, "    %s = %s;\n", keyword[token], stmt);
		(void) fprintf(stdout, "# endif\n");
	    }
	    break;

	case S_COMMENT:
	    if (gettoken(&ptr, defs))
		(void) fprintf(stdout, "    /* %s */\n", defs);
	    break;

	case S_CODE:
	    if (token == T_NEWCODE) {
#ifdef LINEDIRECTIVE
		(void) fprintf(stdout, "# %d \"%s\"\n", lineno + 1, fname);
#endif /* LINEDIRECTIVE */
	    }
	    break;

	default:
	    (void) fprintf(stderr, "%s: \"%s\", %d: Unexpected state\n",
			   pname, fname, lineno);
	    return 1;
	}
    }

    if (inprocess) {
	(void) fprintf(stderr, "%s: \"%s\", %d: Missing enddef\n",
		       pname, fname, lineno);
	return 1;
    }

    if (fp != stdin)
	(void) fclose(fp);

    return 0;
}