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/************************************************************************
* IRC - Internet Relay Chat, include/dbuf.h
* Copyright (C) 1990 Markku Savela
*
* This program 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 1, or (at your option)
* any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* */
#ifndef INCLUDED_dbuf_h
#define INCLUDED_dbuf_h
#ifndef INCLUDED_config_h
#include "config.h"
#endif
#ifndef INCLUDED_sys_types_h
#include <sys/types.h>
#define INCLUDED_sys_types_h
#endif
/*
** dbuf is a collection of functions which can be used to
** maintain a dynamic buffering of a byte stream.
** Functions allocate and release memory dynamically as
** required [Actually, there is nothing that prevents
** this package maintaining the buffer on disk, either]
*/
struct DBufBuffer;
/*
** These structure definitions are only here to be used
** as a whole, *DO NOT EVER REFER TO THESE FIELDS INSIDE
** THE STRUCTURES*! It must be possible to change the internal
** implementation of this package without changing the
** interface.
*/
struct DBuf {
struct DBufBuffer* head; /* First data buffer, if length > 0 */
struct DBufBuffer* tail; /* last data buffer, if length > 0 */
size_t length; /* Current number of bytes stored */
};
extern int DBufCount;
extern int DBufUsedCount;
/*
** dbuf_put
** Append the number of bytes to the buffer, allocating more
** memory as needed. Bytes are copied into internal buffers
** from users buffer.
**
** returns > 0, if operation successfull
** < 0, if failed (due memory allocation problem)
*/
extern int dbuf_put(struct DBuf* dyn, const char* buf, size_t len);
/*
** dbuf_get
** Remove number of bytes from the buffer, releasing dynamic
** memory, if applicaple. Bytes are copied from internal buffers
** to users buffer.
**
** returns the number of bytes actually copied to users buffer,
** if >= 0, any value less than the size of the users
** buffer indicates the dbuf became empty by this operation.
**
** Return 0 indicates that buffer was already empty.
**
** Negative return values indicate some unspecified
** error condition, rather fatal...
*/
extern size_t dbuf_get(struct DBuf* dbuf, char* buf, size_t len);
/*
** dbuf_map, dbuf_delete
** These functions are meant to be used in pairs and offer
** a more efficient way of emptying the buffer than the
** normal 'dbuf_get' would allow--less copying needed.
**
** map returns a pointer to a largest contiguous section
** of bytes in front of the buffer, the length of the
** section is placed into the indicated "long int"
** variable. Returns NULL *and* zero length, if the
** buffer is empty.
**
** delete removes the specified number of bytes from the
** front of the buffer releasing any memory used for them.
**
** Example use (ignoring empty condition here ;)
**
** buf = dbuf_map(&dyn, &count);
** <process N bytes (N <= count) of data pointed by 'buf'>
** dbuf_delete(&dyn, N);
**
** Note: delete can be used alone, there is no real binding
** between map and delete functions...
*/
/*
* dyn - Dynamic buffer header
* len - Return number of bytes accessible
*/
extern const char* dbuf_map(const struct DBuf* dyn, size_t* len);
extern void dbuf_delete(struct DBuf* dyn, size_t len);
/*
** DBufLength
** Return the current number of bytes stored into the buffer.
** (One should use this instead of referencing the internal
** length field explicitly...)
*/
#define DBufLength(dyn) ((dyn)->length)
/*
** DBufClear
** Scratch the current content of the buffer. Release all
** allocated buffers and make it empty.
*/
#define DBufClear(dyn) dbuf_delete((dyn), DBufLength(dyn))
extern int dbuf_getmsg(struct DBuf* dyn, char* buf, size_t len);
extern void dbuf_init(void);
extern void count_dbuf_memory(size_t* allocated, size_t* used);
#endif /* INCLUDED_dbuf_h */
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