dict_private.h

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/*
 * libdict - private definitions.
 *
 * Copyright (c) 2001-2014, Farooq Mela
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#ifndef LIBDICT_DICT_PRIVATE_H__
#define LIBDICT_DICT_PRIVATE_H__
 
#include <stdio.h>
#include <stdlib.h>
 
#include "dict.h"
 
/* A feature (or bug) of this macro is that the expression is always evaluated,
 * regardless of whether NDEBUG is defined or not. This is intentional and
 * sometimes useful. */
#ifndef NDEBUG
# undef ASSERT
# if defined(__GNUC__) || defined(__clang__)
#  define ASSERT(expr) \
    do { \
    if (!__builtin_expect((expr), 1)) { \
        fprintf(stderr, "\n%s:%d (%s) assertion failed: %s\n", \
            __FILE__, __LINE__, __func__, #expr); \
        abort(); \
    } \
    } while (0)
# else
#  define ASSERT(expr) \
    do { \
    if (!(expr)) { \
        fprintf(stderr, "\n%s:%d assertion failed: %s\n", \
            __FILE__, __LINE__, #expr); \
        abort(); \
    } \
    } while (0)
# endif
#else
# define ASSERT(expr)    (void)(expr)
#endif
 
#if defined(__GNUC__) || defined(__clang__)
# define LIKELY(expr)        __builtin_expect((expr), 1)
# define UNLIKELY(expr)        __builtin_expect((expr), 0)
# define VERIFY(expr) \
    do { \
    if (!__builtin_expect((expr), 1)) { \
        fprintf(stderr, "\n%s:%d (%s) verification failed: %s\n", \
            __FILE__, __LINE__, __func__, #expr); \
        return false; \
    } \
    } while (0)
#else
# define LIKELY(expr)        (expr)
# define UNLIKELY(expr)        (expr)
# define VERIFY(expr) \
    do { \
    if (!(expr)) { \
        fprintf(stderr, "\n%s:%d verification failed: %s\n", \
            __FILE__, __LINE__, #expr); \
        return false; \
    } \
    } while (0)
#endif
 
#define MALLOC(n)    (*dict_malloc_func)(n)
#define FREE(p)        (*dict_free_func)(p)
 
#define ABS(a)        ((a) < 0 ? -(a) : (a))
#define MIN(a,b)    ((a) < (b) ? (a) : (b))
#define MAX(a,b)    ((a) > (b) ? (a) : (b))
#define SWAP(a,b,v)    do { v = (a); (a) = (b); (b) = v; } while (0)
 
#if defined(__GNUC__) || defined(__clang__)
# define GCC_INLINE    __inline__
# define GCC_CONST    __attribute__((__const__))
#else
# define GCC_INLINE
# define GCC_CONST
#endif
 
extern long random(void);
static inline unsigned dict_rand(void) { return (unsigned) random(); }
 
/* Number of low-order bits of dict_rand() that are usable: random() is
 * specified to return a value in [0, 2^31), so the top bit of an unsigned is
 * always clear. */
#define DICT_RAND_BITS  31
 
/* Count trailing zero bits of |n|, which must be nonzero. Unlike
 * __builtin_ctz() this is available on every toolchain. */
static inline unsigned
dict_ctz(unsigned n)
{
    ASSERT(n != 0);
#if defined(__GNUC__) || defined(__clang__)
    return (unsigned) __builtin_ctz(n);
#else
    unsigned count = 0;
    while (!(n & 1u)) {
        n >>= 1;
        ++count;
    }
    return count;
#endif
}
 
/* Allocate an array of |n| elements of |size| bytes, or return NULL if the
 * byte count does not fit in a size_t, as it may not where size_t is 32 bits.
 * Without the check the product would wrap and allocate a short array. */
static inline void*
dict_malloc_array(size_t n, size_t size)
{
    if (size && n > SIZE_MAX / size)
        return NULL;
    return MALLOC(n * size);
}
 
/* Drop const from a key pointer for the void*-returning dict_key_func slot.
 * Round-tripping through uintptr_t is well defined and, unlike a direct cast,
 * does not trigger -Wcast-qual. */
static inline void* dict_unconst(const void* p) { return (void*)(uintptr_t)p; }
 
#endif /* !LIBDICT_DICT_PRIVATE_H__ */