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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
#include <stdarg.h>
#include <string.h>
/*
* 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 the fixed buffer runs out of room, the buffer will be set to an error
* state which can be detected with k5_buf_status. Data in a buffer is not
* automatically terminated with a zero byte; call k5_buf_cstring() to use the
* contents as a C string.
*
* k5buf structures are usually stack-allocated. Do not put k5buf structure
* pointers into public APIs. It is okay to reference the data and len fields
* of a buffer (they will be NULL/0 if the buffer is in an error state), but do
* not change them.
*/
/* Buffer type values */
enum k5buftype { K5BUF_ERROR, K5BUF_FIXED, K5BUF_DYNAMIC, K5BUF_DYNAMIC_ZAP };
struct k5buf {
enum k5buftype buftype;
void *data;
size_t space;
size_t len;
};
#define EMPTY_K5BUF { K5BUF_ERROR }
/* 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, void *data, size_t space);
/* Initialize a k5buf using an internally allocated dynamic buffer. */
void k5_buf_init_dynamic(struct k5buf *buf);
/* Initialize a k5buf using an internally allocated dynamic buffer, zeroing
* memory when reallocating or freeing. */
void k5_buf_init_dynamic_zap(struct k5buf *buf);
/* Add a C string to BUF. */
void k5_buf_add(struct k5buf *buf, const char *data);
/* Add a counted series of bytes to BUF. */
void k5_buf_add_len(struct k5buf *buf, const void *data, size_t len);
/* Add sprintf-style formatted data to BUF. For a fixed-length buffer this
* operation will fail if there isn't room for a zero terminator. */
void k5_buf_add_fmt(struct k5buf *buf, const char *fmt, ...)
#if !defined(__cplusplus) && (__GNUC__ > 2)
__attribute__((__format__(__printf__, 2, 3)))
#endif
;
/* Add sprintf-style formatted data to BUF, with a va_list. The value of ap is
* undefined after the call. */
void k5_buf_add_vfmt(struct k5buf *buf, const char *fmt, va_list ap)
#if !defined(__cplusplus) && (__GNUC__ > 2)
__attribute__((__format__(__printf__, 2, 0)))
#endif
;
/* Without changing the length of buf, ensure that there is a zero byte after
* buf.data and return it. Return NULL on error. */
char *k5_buf_cstring(struct k5buf *buf);
/* Extend the length of buf by len and return a pointer to the reserved space,
* to be filled in by the caller. Return NULL on error. */
void *k5_buf_get_space(struct k5buf *buf, size_t len);
/* 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);
/* Return ENOMEM if buf is in an error state, 0 otherwise. */
int k5_buf_status(struct k5buf *buf);
/*
* Free the storage used in the dynamic buffer BUF. The caller may choose to
* take responsibility for freeing the data pointer instead of using this
* function. If BUF is a fixed buffer, an assertion failure will result.
* Freeing a buffer in the error state, a buffer initialized with EMPTY_K5BUF,
* or a zeroed k5buf structure is a no-op.
*/
void k5_buf_free(struct k5buf *buf);
static inline void
k5_buf_add_byte(struct k5buf *buf, uint8_t val)
{
k5_buf_add_len(buf, &val, 1);
}
static inline void
k5_buf_add_uint16_be(struct k5buf *buf, uint16_t val)
{
void *p = k5_buf_get_space(buf, 2);
if (p != NULL)
store_16_be(val, p);
}
static inline void
k5_buf_add_uint16_le(struct k5buf *buf, uint16_t val)
{
void *p = k5_buf_get_space(buf, 2);
if (p != NULL)
store_16_le(val, p);
}
static inline void
k5_buf_add_uint32_be(struct k5buf *buf, uint32_t val)
{
void *p = k5_buf_get_space(buf, 4);
if (p != NULL)
store_32_be(val, p);
}
static inline void
k5_buf_add_uint32_le(struct k5buf *buf, uint32_t val)
{
void *p = k5_buf_get_space(buf, 4);
if (p != NULL)
store_32_le(val, p);
}
static inline void
k5_buf_add_uint64_be(struct k5buf *buf, uint64_t val)
{
void *p = k5_buf_get_space(buf, 8);
if (p != NULL)
store_64_be(val, p);
}
static inline void
k5_buf_add_uint64_le(struct k5buf *buf, uint64_t val)
{
void *p = k5_buf_get_space(buf, 8);
if (p != NULL)
store_64_le(val, p);
}
#endif /* K5_BUF_H */
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