/* This work is copyrighted. See COPYRIGHT.OLD & COPYRIGHT.NEW for   *
*  details. If they are missing then this copy is in violation of    *
*  the copyright conditions.                                        */

/*
 *	comp_parse.c -- The high-level (ha!) parts of the compiler,
 *			that is, the routines which drive the scanner,
 *			etc.
 *
 */

#ifndef AMIGA
#include <unistd.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include "compiler.h"
#include "term.h"
#include "object.h"

extern int read_entry(char *, TERMINAL*);
extern int must_swap();

char	*string_table;
int	next_free;	/* next free character in string_table */
int	table_size = 0; /* current string_table size */
short	term_names;	/* string table offset - current terminal */
int	part2 = 0;	/* set to allow old compiled defns to be used */
int	complete = 0;	/* 1 if entry done with no forward uses */

typedef struct use_item
{
	long	offset;
	struct use_item	*fptr, *bptr;
} USE_ITEM;

struct use_header
{
	USE_ITEM *head, *tail;
};

struct use_header	use_list = {NULL, NULL};
int			use_count = 0;

/*
 *  The use_list is a doubly-linked list with NULLs terminating the lists:
 *
 *	   use_item    use_item    use_item
 *	  ---------   ---------   ---------
 *	  |       |   |       |   |       |   offset
 *        |-------|   |-------|   |-------|
 *	  |   ----+-->|   ----+-->|  NULL |   fptr
 *	  |-------|   |-------|   |-------|
 *	  |  NULL |<--+----   |<--+----   |   bptr
 *	  ---------   ---------   ---------
 *	  ^                       ^
 *	  |  ------------------   |
 *	  |  |       |        |   |
 *	  +--+----   |    ----+---+
 *	     |       |        |
 *	     ------------------
 *	       head     tail
 *	          use_list
 *
 */

static int do_entry(USE_ITEM *);
static void dequeue(USE_ITEM *);
static void init_structure(char *, short *, short *);
static int save_str(char *);
static int handle_use(USE_ITEM *, long, char *, short *, short *);
static void dump_structure(short, char *, short *, short *);
static void check_name(char *);
static int write_object(FILE *, short, char *, short *, short *);

/*
 *	compile()
 *
 *	Main loop of the compiler.
 *
 *	get_token()
 *	if curr_token != NAMES
 *	    err_abort()
 *	while (not at end of file)
 *	    do an entry
 *
 */

void compile()
{
char		line[1024];
int		token_type;
USE_ITEM	*ptr;
int		old_use_count;

	token_type = get_token();

	if (token_type != NAMES)
	    err_abort("File does not start with terminal names in column one");

	while (token_type != EOF)
	    token_type = do_entry(NULL);

	DEBUG0(2, "Starting handling of forward USE's\n");

	for (part2=0; part2<2; part2++) {
	    old_use_count = -1;
	    DEBUG(2, "\n\nPART %d\n\n", part2);
	    while (use_list.head != NULL  &&  old_use_count != use_count) {
		old_use_count = use_count;
		for (ptr = use_list.tail; ptr != NULL; ptr = ptr->bptr) {
		    fseek(curr_fh, ptr->offset, 0);
		    reset_input();
		    if ((token_type = get_token()) != NAMES)
			syserr_abort("Token after a seek not NAMES");
		    (void) do_entry(ptr);
		    if (complete)
			dequeue(ptr);
		}

		for (ptr = use_list.head; ptr != NULL; ptr = ptr->fptr) {
		    fseek(curr_fh, ptr->offset, 0);
		    reset_input();
		    if ((token_type = get_token()) != NAMES)
			syserr_abort("Token after a seek not NAMES");
		    (void) do_entry(ptr);
		    if (complete)
			dequeue(ptr);
		}

		DEBUG0(2, "Finished a pass through enqueued forward USE's\n");
	    }
	}

	if (use_list.head != NULL) {
	    fprintf(stderr, "\nError in following up use-links.  Either there is\n");
	    fprintf(stderr, "a loop in the links or they reference non-existant\n");
	    fprintf(stderr, "terminals.  The following is a list of the entries\n");
	    fprintf(stderr, "involved:\n\n");

	    for (ptr = use_list.head; ptr != NULL; ptr = ptr->fptr) {
		fseek(curr_fh, ptr->offset, 0);
		fgets(line, 1024, curr_fh);
		fprintf(stderr, "%s", line);
	    }

	    exit(1);
	}
}

void dump_list(str)
char *str;
{
	USE_ITEM *ptr;
	char line[512];

	fprintf(stderr, "dump_list %s\n", str);
	for (ptr = use_list.head; ptr != NULL; ptr = ptr->fptr) {
		fseek(curr_fh, ptr->offset, 0);
		fgets(line, 1024, curr_fh);
		fprintf(stderr, "ptr %x off %d bptr %x fptr %x str %s",
		                 (int) ptr,
				 ptr->offset,
				 (int) ptr->bptr,
				 (int) ptr->fptr,
				 line);
	}
	fprintf(stderr, "\n");
}

/*
 *	int
 *	do_entry(item_ptr)
 *
 *	Compile one entry.  During the first pass, item_ptr is NULL.  In pass
 *	two, item_ptr points to the current entry in the use_list.
 *
 *	found-forward-use = FALSE
 *	re-initialise internal arrays
 *	save names in string_table
 *	get_token()
 *	while (not EOF and not NAMES)
 *	    if found-forward-use
 *		do nothing
 *	    else if 'use'
 *		if handle_use() < 0
 *		    found-forward-use = TRUE
 *          else
 *	        check for existance and type-correctness
 *	        enter cap into structure
 *	        if STRING
 *	            save string in string_table
 *	    get_token()
 *      if ! found-forward-use
 *	    clear CANCELS out of the structure
 *	    dump compiled entry into filesystem
 *
 */

int
do_entry(USE_ITEM *item_ptr)
{
long			entry_offset;
int			i;
int			token_type;
struct name_table_entry	*entry_ptr;
int			found_forward_use = FALSE;
char			Booleans[BOOLCOUNT];
short			Numbers[NUMCOUNT], Strings[STRCOUNT];

	init_structure(Booleans, Numbers, Strings);
	complete = 0;
	term_names = save_str(curr_token.tk_name);
	DEBUG(2, "Starting '%s'\n", curr_token.tk_name);
	entry_offset = curr_file_pos;

	for (token_type = get_token();
		token_type != EOF  &&  token_type != NAMES;
		token_type = get_token())
	{
	    if (found_forward_use)
		/* do nothing */ ;
	    else if (strcmp(curr_token.tk_name, "use") == 0) {
		if (handle_use(item_ptr, entry_offset,
					Booleans, Numbers, Strings) < 0)
		    found_forward_use = TRUE;
	    } else {
		entry_ptr = find_entry(curr_token.tk_name);

		if (entry_ptr == NOTFOUND) {
		    warning("Unknown Capability - '%s'",
                                                          curr_token.tk_name);
		    continue;
		}


		if (token_type != CANCEL &&  entry_ptr->nte_type != token_type)
		    warning("Wrong type used for capability '%s'",
			  curr_token.tk_name);
		switch (token_type) {
		    case CANCEL:
			switch (entry_ptr->nte_type) {
			    case BOOLEAN:
				Booleans[entry_ptr->nte_index] = -2;
				break;

			    case NUMBER:
				Numbers[entry_ptr->nte_index] = -2;
				break;

			    case STRING:
				Strings[entry_ptr->nte_index] = -2;
				break;
			}
			break;

		    case BOOLEAN:
			Booleans[entry_ptr->nte_index] = TRUE;
			break;

		    case NUMBER:
			Numbers[entry_ptr->nte_index] =
                                                      curr_token.tk_valnumber;
			break;

		    case STRING:
			Strings[entry_ptr->nte_index] =
                                            save_str(curr_token.tk_valstring);
			break;

		    default:
			warning("Unknown token type");
			panic_mode(',');
			continue;
		}
	    } /* end else cur_token.name != "use" */

	} /* endwhile (not EOF and not NAMES) */

	if (found_forward_use)
	    return(token_type);

	for (i=0; i < BOOLCOUNT; i++) {
	    if (Booleans[i] == -2)
		Booleans[i] = FALSE;
	}

	for (i=0; i < NUMCOUNT; i++) {
	    if (Numbers[i] == -2)
		Numbers[i] = -1;
	}

	for (i=0; i < STRCOUNT; i++) {
	    if (Strings[i] == -2)
		Strings[i] = -1;
	}

	dump_structure(term_names, Booleans, Numbers, Strings);

	complete = 1;
	return(token_type);
}


/*
 *	enqueue(offset)
 *
 *      Put a record of the given offset onto the use-list.
 *
 */

void enqueue(long offset)
{
USE_ITEM *item;

	item = (USE_ITEM *) malloc(sizeof(USE_ITEM));

	if (item == NULL)
	    syserr_abort("Not enough memory for use_list element");

	item->offset = offset;

	if (use_list.head != NULL) {
	    item->bptr = use_list.tail;
	    use_list.tail->fptr = item;
	    item->fptr = NULL;
	    use_list.tail = item;
	} else {
	    use_list.tail = use_list.head = item;
	    item->fptr = item->bptr = NULL;
	}

	use_count ++;
}

/*
 *	dequeue(ptr)
 *
 *	remove the pointed-to item from the use_list
 *
 */

void dequeue(USE_ITEM *ptr)
{
	if (ptr->fptr == NULL)
	    use_list.tail = ptr->bptr;
	else
	    (ptr->fptr)->bptr = ptr->bptr;

	if (ptr->bptr == NULL)
	    use_list.head = ptr->fptr;
	else
	    (ptr->bptr)->fptr = ptr->fptr;

	use_count --;
}

/*
 *	dump_structure()
 *
 *	Save the compiled version of a description in the filesystem.
 *
 *	make a copy of the name-list
 *	break it up into first-name and all-but-last-name
 *	creat(first-name)
 *	write object information to first-name
 *	close(first-name)
 *      for each name in all-but-last-name
 *	    link to first-name
 *
 */

void dump_structure(short term_names, char *Booleans, short *Numbers, short *Strings)
{
struct stat	statbuf;
FILE		*fp;
char		name_list[1024];
char		*first_name, *other_names;
char		*ptr;
char		filename[50];
char		linkname[50];
extern char check_only;

	strcpy(name_list, term_names + string_table);
	DEBUG(7, "Name list = '%s'\n", name_list);

	first_name = name_list;

	ptr = &name_list[strlen(name_list) - 1];
	other_names = ptr + 1;

	while (ptr > name_list  &&  *ptr != '|')
	    ptr--;

	if (ptr != name_list) {
	    *ptr = '\0';

	    for (ptr = name_list; *ptr != '\0'  &&  *ptr != '|'; ptr++)
		;

	    if (*ptr == '\0')
		other_names = ptr;
	    else {
		*ptr = '\0';
		other_names = ptr + 1;
	    }
	}

	if (check_only) {
		DEBUG(1, "Checked %s\n", first_name);
		return;
	}

	DEBUG(7, "First name = '%s'\n", first_name);
	DEBUG(7, "Other names = '%s'\n", other_names);

	if (strlen(first_name) > 100)
	    warning("'%s': terminal name too long.", first_name);

	check_name(first_name);

	sprintf(filename, "%c/%s", first_name[0], first_name);

	if (stat(filename, &statbuf) >= 0  &&  statbuf.st_mtime >= start_time) {
	    warning("'%s' defined in more than one entry.", first_name);
	    fprintf(stderr, "Entry being used is '%s'.\n",
			    (unsigned) term_names + string_table);
	}

	unlink(filename);
	fp = fopen(filename, "w");
	if (fp == NULL) {
	    perror(filename);
	    syserr_abort("Can't open %s/%s\n", destination, filename);
	}
	DEBUG(1, "Created %s\n", filename);

	if (write_object(fp, term_names, Booleans, Numbers, Strings) < 0) {
	    syserr_abort("Error in writing %s/%s", destination, filename);
	}
	fclose(fp);

	while (*other_names != '\0') {
	    ptr = other_names++;
	    while (*other_names != '|'  &&  *other_names != '\0')
		other_names++;

	    if (*other_names != '\0')
		*(other_names++) = '\0';

	    if (strlen(ptr) > 100) {
		warning("'%s': terminal name too long.", ptr);
		continue;
	    }

	    sprintf(linkname, "%c/%s", ptr[0], ptr);

	    if (strcmp(filename, linkname) == 0) {
		warning("Terminal name '%s' synonym for itself", first_name);
	    }
	    else if (stat(linkname, &statbuf) >= 0  &&
						statbuf.st_mtime >= start_time)
	    {
		warning("'%s' defined in more than one entry.", ptr);
		fprintf(stderr, "Entry being used is '%s'.\n",
			    (unsigned) term_names + string_table);
	    } else {
		unlink(linkname);
#ifndef AMIGA
		if (link(filename, linkname) < 0)
		    syserr_abort("Can't link %s to %s", filename, linkname);
#endif
		DEBUG(1, "Linked %s\n", linkname);
	    }
	}
}


/*
 *	int
 *	write_object(fp, term_names, Booleans, Numbers, Strings)
 *
 *	Write out the compiled entry to the given file.
 *	Return 0 if OK or -1 if not.
 *
 */

#define swap(x)		(((x >> 8) & 0377) + 256 * (x & 0377))

#define might_swap(x)	(must_swap()  ?  swap(x)  :  (x))


int
write_object(FILE *fp, short term_names,
	     char *Booleans, short *Numbers, short *Strings)
{
struct header	header;
char		*namelist;
short		namelen;
char		zero = '\0';
int		i;

	namelist = term_names + string_table;
	namelen = strlen(namelist) + 1;

	if (must_swap()) {
	    header.magic = swap(MAGIC);
	    header.name_size = swap(namelen);
	    header.bool_count = swap(BOOLCOUNT);
	    header.num_count = swap(NUMCOUNT);
	    header.str_count = swap(STRCOUNT);
	    header.str_size = swap(next_free);
	} else {
	    header.magic = MAGIC;
	    header.name_size = namelen;
	    header.bool_count = BOOLCOUNT;
	    header.num_count = NUMCOUNT;
	    header.str_count = STRCOUNT;
	    header.str_size = next_free;
	}

	if (fwrite(&header, sizeof(header), 1, fp) != 1
		||  fwrite(namelist, sizeof(char), namelen, fp) != namelen
		||  fwrite(Booleans, sizeof(char), BOOLCOUNT, fp) != BOOLCOUNT)
	    return(-1);

	if ((namelen+BOOLCOUNT) % 2 != 0  &&  fwrite(&zero, sizeof(char), 1, fp) != 1)
	    return(-1);

	if (must_swap()) {
	    for (i=0; i < NUMCOUNT; i++)
		Numbers[i] = swap(Numbers[i]);
	    for (i=0; i < STRCOUNT; i++)
		Strings[i] = swap(Strings[i]);
	}

	if (fwrite(Numbers, sizeof(short), NUMCOUNT, fp) != NUMCOUNT
	       ||  fwrite(Strings, sizeof(short), STRCOUNT, fp) != STRCOUNT
	       ||  fwrite(string_table, sizeof(char), next_free, fp)
								  != next_free)
	    return(-1);

        return(1);
}


/*
 *	check_name(name)
 *
 *	Generate an error message if given name does not begin with a
 *	digit or lower-case letter.
 *
 */

void check_name(char *name)
{
	if (! isdigit(name[0])  &&  ! islower(name[0])) {
	    fprintf(stderr, "compile: Line %d: Illegal terminal name - '%s'\n",
							    curr_line, name);
	    fprintf(stderr,
			"Terminal names must start with lowercase or digit\n");
	    exit(1);
	}
}


/*
 *	int
 *	save_str(string)
 *
 *	copy string into next free part of string_table, doing a realloc()
 *	if necessary.  return offset of beginning of string from start of
 *	string_table.
 *
 */

int save_str(char *string)
{
int	old_next_free = next_free;

	if (table_size == 0) {
	    if ((string_table = malloc(1024)) == NULL)
		syserr_abort("Out of memory");
	    table_size = 1024;
	    DEBUG(5, "Made initial string table allocation.  Size is %d\n",
								    table_size);
	}

	while (table_size < next_free + strlen(string)) {
	    if ((string_table = realloc(string_table, table_size + 1024))
									== NULL)
		syserr_abort("Out of memory");
	    table_size += 1024;
	    DEBUG(5, "Extended string table.  Size now %d\n", table_size);
	}

	strcpy(&string_table[next_free], string);
	DEBUG(7, "Saved string '%s' ", string);
	DEBUG(7, "at location %d\n", next_free);
	next_free += strlen(string) + 1;

	return(old_next_free);
}


/*
 *	init_structure(Booleans, Numbers, Strings)
 *
 *	Initialise the given arrays
 *	Reset the next_free counter to zero.
 *
 */

void init_structure(char *Booleans, short *Numbers, short *Strings)
{
int	i;

	for (i=0; i < BOOLCOUNT; i++)
	    Booleans[i] = FALSE;

	for (i=0; i < NUMCOUNT; i++)
	    Numbers[i] = -1;

	for (i=0; i < STRCOUNT; i++)
	    Strings[i] = -1;

	next_free = 0;
}


/*
**	int
**	handle_use(item_ptr, entry_offset, Booleans, Numbers, Strings)
**
**	Merge the compiled file whose name is in cur_token.valstring
**	with the current entry.
**
**		if it's a forward use-link
**	    	    if item_ptr == NULL
**		        queue it up for later handling
**	            else
**		        ignore it (we're already going through the queue)
**	        else it's a backward use-link
**	            read in the object file for that terminal
**	            merge contents with current structure
**
**	Returned value is 0 if it was a backward link and we
**	successfully read it in, -1 if a forward link.
*/

int handle_use(USE_ITEM *item_ptr, long entry_offset,
               char *Booleans, short *Numbers, short *Strings)
{
struct term	use_term;
struct stat	statbuf;
char		filename[50];
int             i;

	check_name(curr_token.tk_valstring);

	sprintf(filename, "%c/%s", curr_token.tk_valstring[0],
                                                     curr_token.tk_valstring);

	if (stat(filename, &statbuf) < 0  ||  (part2==0 && statbuf.st_mtime < start_time)) {
	    DEBUG(2, "Forward USE to %s", curr_token.tk_valstring);

 	    if (item_ptr == NULL) {
 		DEBUG0(2, " (enqueued)\n");
 		enqueue(entry_offset);
 	    } else
 		DEBUG0(2, " (skipped)\n");

	    return(-1);
	} else {
	    DEBUG(2, "Backward USE to %s\n", curr_token.tk_valstring);
	    if (read_entry(filename, &use_term) < 0)
		syserr_abort("Error in re-reading compiled file %s", filename);

	    for (i=0; i < BOOLCOUNT; i++) {
		if (Booleans[i] == FALSE  &&  use_term.Booleans[i] == TRUE)
		    Booleans[i] = TRUE;
	    }

	    for (i=0; i < NUMCOUNT; i++) {
		if (Numbers[i] == -1  &&  use_term.Numbers[i] != -1)
		    Numbers[i] = use_term.Numbers[i];
	    }

	    for (i=0; i < STRCOUNT; i++) {
		if (Strings[i] == -1  &&  use_term.Strings[i] != (char *) 0)
		    Strings[i] = save_str(use_term.Strings[i]);
	    }

	}
        return(1);
}