tok822_node.c

[詳解]

/*++
/* NAME
/*  tok822_node 3
/* SUMMARY
/*  token memory management
/* SYNOPSIS
/*  #include <tok822.h>
/*
/*  TOK822  *tok822_alloc(type, strval)
/*  int type;
/*  const char *strval;
/*
/*  TOK822  *tok822_free(tp)
/*  TOK822  *tp;
/* DESCRIPTION
/*  This module implements memory management for token
/*  structures. A distinction is made between single-character
/*  tokens that have no string value, and string-valued tokens.
/*
/*  tok822_alloc() allocates memory for a token structure of
/*  the named type, and initializes it properly. In case of
/*  a single-character token, no string memory is allocated.
/*  Otherwise, \fIstrval\fR is a null pointer or provides
/*  string data to initialize the token with.
/*
/*  tok822_free() releases the memory used for the specified token
/*  and conveniently returns a null pointer value.
/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*--*/

/* System library. */

#include <sys_defs.h>
#include <string.h>

/* Utility library. */

#include <mymalloc.h>
#include <vstring.h>

/* Global library. */

#include "tok822.h"

/* tok822_alloc - allocate and initialize token */

TOK822 *tok822_alloc(int type, const char *strval)
{
    TOK822 *tp;

#define CONTAINER_TOKEN(x) \
    ((x) == TOK822_ADDR || (x) == TOK822_STARTGRP)

    tp = (TOK822 *) mymalloc(sizeof(*tp));
    tp->type = type;
    tp->next = tp->prev = tp->head = tp->tail = tp->owner = 0;
    tp->vstr = (type < TOK822_MINTOK || CONTAINER_TOKEN(type) ? 0 :
        strval == 0 ? vstring_alloc(10) :
        vstring_strcpy(vstring_alloc(strlen(strval) + 1), strval));
    return (tp);
}

/* tok822_free - destroy token */

TOK822 *tok822_free(TOK822 *tp)
{
    if (tp->vstr)
    vstring_free(tp->vstr);
    myfree((void *) tp);
    return (0);
}