/*
 * libnogg: a decoder library for Ogg Vorbis streams
 * Copyright (c) 2014-2026 Andrew Church <achurch@achurch.org>
 *
 * This software may be copied and redistributed under certain conditions;
 * see the file "COPYING" in the source code distribution for details.
 * NO WARRANTY is provided with this software.
 */

/* Note that this header is shared with tool sources and should not
 * include any library-specific declarations. */

#ifndef NOGG_SRC_BASE_H
#define NOGG_SRC_BASE_H

/*************************************************************************/
/***************************** Helper macros *****************************/
/*************************************************************************/

/*
 * Convenience macros for testing compiler versions.  major and minor must
 * be literal integers.  The #ifdef mess is required because C99 doesn't
 * allow defined() to be generated by a macro (6.10.1.2).
 *
 * Note that these macros will evaluate to true for any compiler which
 * claims via the relevant preprocessor symbols to be compatible with the
 * named compiler.  This is particularly common with GCC; for example, most
 * versions of Clang also satisfy IS_GCC(4,2).
 */

#ifdef __clang__
    #define IS_CLANG(major,minor)  \
        (__clang_major__ > major \
         || (__clang_major__ == major && __clang_minor__ >= minor))
#else
    #define IS_CLANG(major,minor)  0
#endif

#ifdef __GNUC__
    #define IS_GCC(major,minor)  \
        (__GNUC__ > major || (__GNUC__ == major && __GNUC_MINOR__ >= minor))
#else
    #define IS_GCC(major,minor)  0
#endif

/*-----------------------------------------------------------------------*/

/* Suppress version-dependent spurious diagnostics. */
#if IS_GCC(15,0) || IS_CLANG(21,0)
# pragma GCC diagnostic ignored "-Wunterminated-string-initialization"
#endif

/*-----------------------------------------------------------------------*/

/**
 * ALIGN:  Attribute indicating that the object to which it is attached
 * should be aligned to a multiple of the given number of bytes, which
 * must be a power of two.
 */
#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
# define ALIGN(alignment)  _Alignas(alignment)
#elif IS_GCC(2,95) || IS_CLANG(1,0)
# define ALIGN(alignment)  __attribute__((aligned(alignment)))
#else
# define ALIGN(alignment)  /*nothing*/
#endif

/**
 * ASSERT:  Verify that the given condition is true, and abort the program
 * if it is not.  If ENABLE_ASSERT is not defined, the expression is
 * evaluated and its result is discarded; if supported by the compiler, a
 * hint is provided that the expression is always true.
 */
#ifdef ENABLE_ASSERT
# include <assert.h>
# define ASSERT  assert
#else
# define ASSERT(expr)  do {if (UNLIKELY(!(expr))) {UNREACHABLE;}} while (0)
#endif

/**
 * COLD_FUNCTION:  Function attribute indicating that the given function
 * is not expected to be called often.
 */
#if IS_GCC(4,3) || IS_CLANG(3,2)
# define COLD_FUNCTION  __attribute__((cold))
#else
# define COLD_FUNCTION  /*nothing*/
#endif

/**
 * CONST_FUNCTION:  Function attribute indicating that the function's
 * behavior depends only on its arguments and the function has no side
 * effects.
 */
#if IS_GCC(2,95) || IS_CLANG(1,0)
# define CONST_FUNCTION  __attribute__((const))
#else
# define CONST_FUNCTION  /*nothing*/
#endif

/**
 * PURE_FUNCTION:  Function attribute indicating that the function's
 * behavior depends only on its arguments and global state, and the
 * function has no side effects.
 */
#if IS_GCC(3,0) || IS_CLANG(1,0)
# define PURE_FUNCTION  __attribute__((pure))
#else
# define PURE_FUNCTION  /*nothing*/
#endif

/**
 * LIKELY, UNLIKELY:  Construct which indicates to the compiler that the
 * given expression is likely or unlikely to evaluate to true.
 */
#if IS_GCC(3,0) || IS_CLANG(1,0)
# define LIKELY(expr)    (__builtin_expect(!!(expr), 1))
# define UNLIKELY(expr)  (__builtin_expect(!!(expr), 0))
#else
# define LIKELY(expr)    (expr)
# define UNLIKELY(expr)  (expr)
#endif

/**
 * NOINLINE:  Function attribute indicating that the function should not
 * be inlined.
 */
#if IS_GCC(3,1) || IS_CLANG(1,0)
# define NOINLINE  __attribute__((noinline))
#elif defined(_MSC_VER)
# define NOINLINE  __declspec(noinline)
#else
# define NOINLINE  /*nothing*/
#endif

/**
 * UNREACHABLE:  Compiler intrinsic indicating that the current code
 * location can never be reached.
 */
#if IS_GCC(4,5) || IS_CLANG(2,7)
# define UNREACHABLE  __builtin_unreachable()
#else
# define UNREACHABLE  /*nothing*/
#endif

/**
 * UNUSED:  Attribute indicating that a definition is intentionally unused.
 */
#if IS_GCC(2,95) || IS_CLANG(1,0)
# define UNUSED  __attribute__((unused))
#else
# define UNUSED  /*nothing*/
#endif

/**
 * min, max:  Return the minimum or maximum of two values.  The returned
 * value will be evaluated twice.
 */
#define min(a,b)  ((a) < (b) ? (a) : (b))
#define max(a,b)  ((a) > (b) ? (a) : (b))

/**
 * lenof:  Return the length of (number of elements in) the given array.
 */
#define lenof(array)  ((int)(sizeof((array)) / sizeof(*(array))))

/*************************************************************************/
/*************************************************************************/

#endif  // NOGG_SRC_BASE_H