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/*++
/* NAME
/* strsave 3
/* SUMMARY
/* maintain unique copy of a string
/* SYNOPSIS
/* char *strsave(string)
/* char *string;
/* DESCRIPTION
/* This function returns a pointer to an unique copy of its
/* argument.
/* DIAGNOSTISC
/* strsave() calls fatal() when it runs out of memory.
/* AUTHOR(S)
/* Wietse Venema
/* Eindhoven University of Technology
/* Department of Mathematics and Computer Science
/* Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
/* LAST MODIFICATION
/* 92/01/15 21:53:13
/* VERSION/RELEASE
/* 1.1
/*--*/
static char strsave_sccsid[] = "@(#) strsave.c 1.1 92/01/15 21:53:13";
/* C library */
extern char *strcpy();
extern char *malloc();
/* Application-specific stuff */
#include "error.h"
#define STR_TABSIZE 100
struct string {
char *strval; /* unique string copy */
struct string *next; /* next one in hash chain */
};
static struct string *str_tab[STR_TABSIZE] = {0,};
/* More string stuff. Maybe it should go to an #include file. */
#define STREQ(x,y) (*(x) == *(y) && strcmp((x),(y)) == 0)
/* strsave - save unique copy of string */
char *strsave(str)
register char *str;
{
register struct string *s;
register int where = hash(str, STR_TABSIZE);
/* Look for existing entry. */
for (s = str_tab[where]; s; s = s->next)
if (STREQ(str, s->strval))
return (s->strval);
/* Add new entry. */
if ((s = (struct string *) malloc(sizeof(*s))) == 0
|| (s->strval = malloc(strlen(str) + 1)) == 0)
fatal("out of memory");
s->next = str_tab[where];
str_tab[where] = s;
return (strcpy(s->strval, str));
}
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