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/* Temporary string handling -- header
* Copyright (C) 2009 Chris Hall (GMCH), Highwayman
*
* This file is part of GNU Zebra.
*
* GNU Zebra is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2, or (at your
* option) any later version.
*
* GNU Zebra is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Zebra; see the file COPYING. If not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifndef _ZEBRA_TSTRING_H
#define _ZEBRA_TSTRING_H
#include "misc.h"
#include "zassert.h"
#include "memory.h"
/*==============================================================================
* tstrings are allocated on the stack, but if (unexpectedly) the standard
* size is not enough, then they can be allocated dynamically.
*
* To declare a "tstring":
*
* tstring(foo, 64) ; // creates a "tstring" variable called "foo"
* // with 64 char buffer.
*
* Can then:
*
* s = tstring_set_len(foo, n) ; // ensures have buffer for n+1 chars
* s = tstring_set(foo, "...") ; // copies "..." (with '\0') to buffer
* s = tstring_set_n(foo, q, n) ; // copies n characters from q to buffer
* and '\0' terminates
*
* If can fit stuff in the buffer, will do so. Otherwise will allocate an
* MTYPE_TMP buffer to work in.
*
* And before leaving the scope of "foo" must:
*
* tstring_free(foo) ; // releases any dynamically allocated memory.
*/
struct tstring
{
usize size ;
char* str ;
char* alloc ;
} ;
typedef struct tstring tstring[1] ;
/* tstring(foo, 93) ; -- declare the variable "foo". */
#define tstring_t(name, sz) \
char _zlxq_##name##_b[ ((sz) + 7) & 0xFFFFFFF8] ; \
tstring name = { { .size = ((sz) + 7) & 0xFFFFFFF8, \
.str = _zlxq_##name##_b, \
.alloc = NULL } }
/*------------------------------------------------------------------------------
* Ensure the tstring "foo" can accomodate at least "len" characters plus the
* terminating '\0'.
*
* Returns: address of buffer
*
* NB: address of buffer may not be the same as returned by a previous operation
* on foo. Also, previous contents of foo may be lost.
*/
Inline char*
tstring_set_len(struct tstring* ts, usize len)
{
if (len >= ts->size)
{
ts->size = len + 1 ;
ts->str = ts->alloc = XREALLOC(MTYPE_TMP, ts->alloc, len + 1) ;
} ;
return ts->str ;
} ;
/*------------------------------------------------------------------------------
* Copy "len" characters from "src" to the tstring "foo", and append a
* terminating '\0'.
*
* The "src" address is ignored if "len" == 0 (sets "foo" to be empty string).
*
* Returns: address of buffer
*
* NB: address of buffer may not be the same as returned by a previous operation
* on foo. Also, previous contents of foo may be lost.
*/
static inline char*
tstring_set_n(struct tstring* ts, const char* str, usize len)
{
char* tss = tstring_set_len(ts, len) ;
if (len > 0)
memcpy(tss, str, len) ;
*(tss + len) = '\0' ;
return tss ;
} ;
/*------------------------------------------------------------------------------
* Copy the string "str" to the tstring "foo", with terminating '\0'.
*
* If "str" is NULL, sets "foo" to be an empty string.
*
* Returns: address of buffer
*
* NB: address of buffer may not be the same as returned by a previous operation
* on foo. Also, previous contents of foo may be lost.
*/
static inline char*
tstring_set(struct tstring* ts, const char* str)
{
return tstring_set_n(ts, str, (str != NULL) ? strlen(str) : 0) ;
} ;
/*------------------------------------------------------------------------------
* If have dynamically allocated buffer for tstring "foo", release it now.
*/
static inline void
tstring_free(struct tstring* ts)
{
if (ts->alloc != NULL)
XFREE(MTYPE_TMP, ts->alloc) ; /* sets ts->alloc NULL */
} ;
#endif /* _ZEBRA_TSTRING_H */
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