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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* include/k5-buf.h - k5buf interface declarations */
/*
* Copyright 2008 Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*/
#ifndef K5_BUF_H
#define K5_BUF_H
#if defined(_MSDOS) || defined(_WIN32)
#include <win-mac.h>
#endif
#ifndef KRB5_CALLCONV
#define KRB5_CALLCONV
#define KRB5_CALLCONV_C
#endif
#include <stdarg.h>
#include <string.h>
#ifndef _WIN32
#include <unistd.h>
#endif
/*
* The k5buf module is intended to allow multi-step string construction in a
* fixed or dynamic buffer without the need to check for a failure at each step
* (and without aborting on malloc failure). If an allocation failure occurs
* or if the fixed buffer runs out of room, the error will be discovered when
* the caller retrieves the C string value or checks the length of the
* resulting buffer.
*
* k5buf structures are stack-allocated, but are intended to be opaque, so do
* not access the fields directly. This is a tool, not a way of life, so do
* not put k5buf structure pointers into the public API or into significant
* internal APIs.
*/
/*
* We must define the k5buf structure here to allow stack allocation. The
* structure is intended to be opaque, so the fields have funny names.
*/
struct k5buf {
int xx_buftype;
char *xx_data;
size_t xx_space;
size_t xx_len;
};
/* Initialize a k5buf using a fixed-sized, existing buffer. SPACE must be
* more than zero, or an assertion failure will result. */
void k5_buf_init_fixed(struct k5buf *buf, char *data, size_t space);
/* Initialize a k5buf using an internally allocated dynamic buffer. The
* buffer contents must be freed with k5_free_buf. */
void k5_buf_init_dynamic(struct k5buf *buf);
/* Add a C string to BUF. */
void k5_buf_add(struct k5buf *buf, const char *data);
/*
* Add a counted set of bytes to BUF. It is okay for DATA[0..LEN-1]
* to contain null bytes if you are prepared to deal with that in the
* output (use k5_buf_len to retrieve the length of the output).
*/
void k5_buf_add_len(struct k5buf *buf, const char *data, size_t len);
/* Add sprintf-style formatted data to BUF. */
void k5_buf_add_fmt(struct k5buf *buf, const char *fmt, ...)
#if !defined(__cplusplus) && (__GNUC__ > 2)
__attribute__((__format__(__printf__, 2, 3)))
#endif
;
/* Truncate BUF. LEN must be between 0 and the existing buffer
* length, or an assertion failure will result. */
void k5_buf_truncate(struct k5buf *buf, size_t len);
/*
* Retrieve the byte array value of BUF, or NULL if there has been an
* allocation failure or the fixed buffer ran out of room.
*
* The byte array will be a C string unless binary data was added with
* k5_buf_add_len; it will be null-terminated regardless. Modifying the byte
* array does not invalidate the buffer, as long as its length is not changed.
*
* For a fixed buffer, the return value will always be equal to the passed-in
* value of DATA at initialization time if it is not NULL.
*
* For a dynamic buffer, any buffer modification operation except
* k5_buf_truncate may invalidate the byte array address.
*/
char *k5_buf_data(struct k5buf *buf);
/*
* Retrieve the length of BUF, or -1 if there has been an allocation failure or
* the fixed buffer ran out of room. The length is equal to
* strlen(k5_buf_data(buf)) unless binary data was added with k5_buf_add_len.
*/
ssize_t k5_buf_len(struct k5buf *buf);
/*
* Free the storage used in the dynamic buffer BUF. The caller may choose to
* take responsibility for freeing the return value of k5_buf_data instead of
* using this function. If BUF is a fixed buffer, an assertion failure will
* result. It is unnecessary (though harmless) to free a buffer after an error
* is detected; the storage will already have been freed in that case.
*/
void k5_free_buf(struct k5buf *buf);
#endif /* K5_BUF_H */
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