path: root/src/include/gnunet_common.h

/*
     This file is part of GNUnet.
     Copyright (C) 2006-2013 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.

     GNUnet 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
     Affero General Public License for more details.
    
     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file include/gnunet_common.h
 * @brief commonly used definitions; globals in this file
 *        are exempt from the rule that the module name ("common")
 *        must be part of the symbol name.
 *
 * @author Christian Grothoff
 * @author Nils Durner
 *
 * @defgroup logging Logging
 * @see [Documentation](https://gnunet.org/logging)
 *
 * @defgroup memory Memory management
 */
#ifndef GNUNET_COMMON_H
#define GNUNET_COMMON_H

#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef MINGW
#include "winproc.h"
#endif
#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif
#ifdef HAVE_STDARG_H
#include <stdarg.h>
#endif

#ifdef HAVE_BYTESWAP_H
#include <byteswap.h>
#endif

#ifdef __cplusplus
extern "C"
{
#if 0                           /* keep Emacsens' auto-indent happy */
}
#endif
#endif

/**
 * Version of the API (for entire gnunetutil.so library).
 */
#define GNUNET_UTIL_VERSION 0x000A0102


/**
 * Named constants for return values.  The following invariants hold:
 * `GNUNET_NO == 0` (to allow `if (GNUNET_NO)`) `GNUNET_OK !=
 * GNUNET_SYSERR`, `GNUNET_OK != GNUNET_NO`, `GNUNET_NO !=
 * GNUNET_SYSERR` and finally `GNUNET_YES != GNUNET_NO`.
 */
#define GNUNET_OK      1
#define GNUNET_SYSERR -1
#define GNUNET_YES     1
#define GNUNET_NO      0

#define GNUNET_MIN(a,b) (((a) < (b)) ? (a) : (b))

#define GNUNET_MAX(a,b) (((a) > (b)) ? (a) : (b))

/* some systems use one underscore only, and mingw uses no underscore... */
#ifndef __BYTE_ORDER
#ifdef _BYTE_ORDER
#define __BYTE_ORDER _BYTE_ORDER
#else
#ifdef BYTE_ORDER
#define __BYTE_ORDER BYTE_ORDER
#endif
#endif
#endif
#ifndef __BIG_ENDIAN
#ifdef _BIG_ENDIAN
#define __BIG_ENDIAN _BIG_ENDIAN
#else
#ifdef BIG_ENDIAN
#define __BIG_ENDIAN BIG_ENDIAN
#endif
#endif
#endif
#ifndef __LITTLE_ENDIAN
#ifdef _LITTLE_ENDIAN
#define __LITTLE_ENDIAN _LITTLE_ENDIAN
#else
#ifdef LITTLE_ENDIAN
#define __LITTLE_ENDIAN LITTLE_ENDIAN
#endif
#endif
#endif

/**
 * @ingroup logging
 * define #GNUNET_EXTRA_LOGGING if using this header outside the GNUnet source
 * tree where gnunet_config.h is unavailable
 */
#ifndef GNUNET_EXTRA_LOGGING
#define GNUNET_EXTRA_LOGGING 0
#endif

/**
 * Endian operations
 */

# if __BYTE_ORDER == __LITTLE_ENDIAN
#  define GNUNET_htobe16(x) __bswap_16 (x)
#  define GNUNET_htole16(x) (x)
#  define GNUNET_be16toh(x) __bswap_16 (x)
#  define GNUNET_le16toh(x) (x)

#  define GNUNET_htobe32(x) __bswap_32 (x)
#  define GNUNET_htole32(x) (x)
#  define GNUNET_be32toh(x) __bswap_32 (x)
#  define GNUNET_le32toh(x) (x)

#  define GNUNET_htobe64(x) __bswap_64 (x)
#  define GNUNET_htole64(x) (x)
#  define GNUNET_be64toh(x) __bswap_64 (x)
#  define GNUNET_le64toh(x) (x)
#endif
# if __BYTE_ORDER == __BIG_ENDIAN
#  define GNUNET_htobe16(x) (x)
#  define GNUNET_htole16(x) __bswap_16 (x)
#  define GNUNET_be16toh(x) (x)
#  define GNUNET_le16toh(x) __bswap_16 (x)

#  define GNUNET_htobe32(x) (x)
#  define GNUNET_htole32(x) __bswap_32 (x)
#  define GNUNET_be32toh(x) (x)
#  define GNUNET_le32toh(x) __bswap_32 (x)

#  define GNUNET_htobe64(x) (x)
#  define GNUNET_htole64(x) __bswap_64 (x)
#  define GNUNET_be64toh(x) (x)
#  define GNUNET_le64toh(x) __bswap_64 (x)
#endif


/**
 * Macro used to avoid using 0 for the length of a variable-size
 * array (Non-Zero-Length).
 *
 * Basically, C standard says that "int[n] x;" is undefined if n=0.
 * This was supposed to prevent issues with pointer aliasing.
 * However, C compilers may conclude that n!=0 as n=0 would be
 * undefined, and then optimize under the assumption n!=0, which
 * could cause actual issues.  Hence, when initializing an array
 * on the stack with a variable-length that might be zero, write
 * "int[GNUNET_NZL(n)] x;" instead of "int[n] x".
 */
#define GNUNET_NZL(l) GNUNET_MAX(1,l)


/**
 * gcc-ism to get packed structs.
 */
#define GNUNET_PACKED __attribute__((packed))

/**
 * gcc-ism to get gcc bitfield layout when compiling with -mms-bitfields
 */
#if MINGW
#define GNUNET_GCC_STRUCT_LAYOUT __attribute__((gcc_struct))
#else
#define GNUNET_GCC_STRUCT_LAYOUT
#endif

/**
 * gcc-ism to force alignment; we use this to align char-arrays
 * that may then be cast to 'struct's.  See also gcc
 * bug #33594.
 */
#ifdef __BIGGEST_ALIGNMENT__
#define GNUNET_ALIGN __attribute__((aligned (__BIGGEST_ALIGNMENT__)))
#else
#define GNUNET_ALIGN __attribute__((aligned (8)))
#endif

/**
 * gcc-ism to document unused arguments