string.c

四皇后问题

/*
	Little Smalltalk

		string creation and deletion
		timothy a. budd, 10/84
*/
/*
	The source code for the Little Smalltalk System may be freely
	copied provided that the source of all files is acknowledged
	and that this condition is copied with each file.

	The Little Smalltalk System is distributed without responsibility
	for the performance of the program and without any guarantee of
	maintenance.

	All questions concerning Little Smalltalk should be addressed to:

		Professor Tim Budd
		Department of Computer Science
		Oregon State University
		Corvallis, Oregon
		97331
		USA
*/
# include <stdio.h>
# include "object.h"
# include "string.h"

int ca_str = 0;
int ca_wal = 0;

/* walloc allocates a string containing the same chars as the arg */

# define WALLOCINITSIZE 1000

static char wtable[WALLOCINITSIZE];
int wtop = 0;

char *walloc(val)
char *val;
{	char *p;
	int  size;

	size = 1 + strlen(val);
	if ((size < 40) && ((wtop + size) < WALLOCINITSIZE)) {
		p = &wtable[wtop];
		wtop += size;
		}
	else {
		p = o_alloc((unsigned) size);
		ca_wal++;
		}
	strcpy(p, val);
	return(p);
}

/*---------------------------------------*/
extern class *ArrayedCollection;
extern object *o_acollection;

static mstruct *fr_string = 0;

# define STRINITSIZE 50

static string st_init_table[STRINITSIZE];

str_init() {
	string *p;
	mstruct *new;
	int i;

	for (p = st_init_table, i = 0; i < STRINITSIZE; i++, p++) {
		new = (mstruct *) p;
		new->mlink = fr_string;
		fr_string = new;
		}
}

extern int started;
static new_rstr(new)
string *new;
{
	new->s_ref_count = 0;
	new->s_size = STRINGSIZE;
	if (! started)
		sassign(new->s_super_obj, o_acollection);
	else if (ArrayedCollection)
		sassign(new->s_super_obj, new_inst(ArrayedCollection));
	else
		new->s_super_obj = (object *) 0;
}

string *new_istr(text)
char *text;
{	register string *new;

	if (fr_string) {
		new = (string *) fr_string;
		fr_string = fr_string->mlink;
		}
	else {
		ca_str++;
		new = structalloc(string);
		}

	new->s_value = text;
	new_rstr(new);
	return(new);
}

# define STRLISTMAX 100

mstruct *frl_str[STRLISTMAX];

object *new_str(text)
char *text;
{	int size;
	string *new;

	size = 1 + strlen(text);
	if ((size < STRLISTMAX) && frl_str[size]) {
		new = (string *) frl_str[size];
		frl_str[size] = frl_str[size]->mlink;
		strcpy(new->s_value, text);
		new_rstr(new);
		}
	else {
		new = new_istr(walloc(text));
		}
	return((object *) new);
}

free_string(s)
string *s;
{	int size;

	if (s->s_super_obj)
		obj_dec(s->s_super_obj);
	size = 1 + strlen(s->s_value);
	if (size < STRLISTMAX) {
		((mstruct *)s)->mlink = frl_str[size];
		frl_str[size] = (mstruct *) s;
		}
	else {
		((mstruct *)s)->mlink = fr_string;
		fr_string = (mstruct *) s;
		}
}