hash_key.h

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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2021 Mike Becker, Olaf Wintermann 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 HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * 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 UCX_HASH_KEY_H
#define UCX_HASH_KEY_H
 
#include "common.h"
#include "string.h"

struct cx_hash_key_s {
    const void *data;
    size_t len;
    uint64_t hash;
};

typedef struct cx_hash_key_s CxHashKey;

CX_EXTERN CX_NONNULL
void cx_hash_murmur(CxHashKey *key);

CX_INLINE
uint32_t cx_hash_u32(uint32_t x) {
    x = ((x >> 16) ^ x) * 0x45d9f3bu;
    x = ((x >> 16) ^ x) * 0x45d9f3bu;
    x = (x >> 16) ^ x;
    return x;
}

CX_INLINE
uint64_t cx_hash_u64(uint64_t x){
    x = (x ^ (x >> 30)) * UINT64_C(0xbf58476d1ce4e5b9);
    x = (x ^ (x >> 27)) * UINT64_C(0x94d049bb133111eb);
    x = x ^ (x >> 31);
    return x;
}

CX_EXTERN CX_NODISCARD CX_ACCESS_R(1, 2)
CxHashKey cx_hash_key(const void *obj, size_t len);

CX_NODISCARD CX_INLINE
CxHashKey cx_hash_key_u32(uint32_t x) {
    CxHashKey key;
    key.data = NULL;
    key.len = 0;
    key.hash = cx_hash_u32(x);
    return key;
}

CX_NODISCARD CX_INLINE
CxHashKey cx_hash_key_u64(uint64_t x) {
    CxHashKey key;
    key.data = NULL;
    key.len = 0;
    key.hash = cx_hash_u64(x);
    return key;
}

CX_NODISCARD CX_CSTR_ARG(1) CX_INLINE
CxHashKey cx_hash_key_str(const char *str) {
    return cx_hash_key((const void*)str, str == NULL ? 0 : strlen(str));
}

CX_NODISCARD CX_CSTR_ARG(1) CX_INLINE
CxHashKey cx_hash_key_ustr(const unsigned char *str) {
    return cx_hash_key((const void*)str, str == NULL ? 0 : strlen((const char*)str));
}

CX_NODISCARD CX_ACCESS_R(1, 2) CX_INLINE
CxHashKey cx_hash_key_bytes(const unsigned char *bytes, size_t len) {
    return cx_hash_key((const void*)bytes, len);
}

CX_NODISCARD CX_INLINE
CxHashKey cx_hash_key_cxstr(cxstring str) {
    return cx_hash_key((void*)str.ptr, str.length);
}

CX_NODISCARD CX_INLINE
CxHashKey cx_hash_key_mutstr(cxmutstr str) {
    return cx_hash_key((void*)str.ptr, str.length);
}

CX_NODISCARD CX_INLINE
CxHashKey cx_hash_key_identity(CxHashKey key) {
    return key;
}

CX_NODISCARD CX_INLINE
CxHashKey cx_hash_key_deref(const CxHashKey *key) {
    return *key;
}
 
#ifndef __cplusplus
#define CX_HASH_KEY(key) _Generic((key), \
        CxHashKey*: cx_hash_key_deref, \
        const CxHashKey*: cx_hash_key_deref, \
        CxHashKey: cx_hash_key_identity, \
        cxstring: cx_hash_key_cxstr, \
        cxmutstr: cx_hash_key_mutstr, \
        char*: cx_hash_key_str, \
        const char*: cx_hash_key_str, \
        unsigned char*: cx_hash_key_ustr, \
        const unsigned char*: cx_hash_key_ustr, \
        uint32_t: cx_hash_key_u32, \
        uint64_t: cx_hash_key_u64) \
        (key)
#endif // __cplusplus

CX_EXTERN CX_NODISCARD CX_NONNULL
int cx_hash_key_cmp(const void *left, const void *right);

CX_EXTERN
cxstring cx_hash_key_as_string(const CxHashKey *key);
 
#ifdef __cplusplus
// ----------------------------------------------------------
// Overloads of CX_HASH_KEY (the C++ version of a _Generic)
// ----------------------------------------------------------
 
CX_CPPDECL CxHashKey CX_HASH_KEY(CxHashKey key) {
    return key;
}
 
CX_CPPDECL CxHashKey CX_HASH_KEY(const CxHashKey *key) {
    return *key;
}
 
CX_CPPDECL CxHashKey CX_HASH_KEY(cxstring str) {
    return cx_hash_key_cxstr(str);
}
 
CX_CPPDECL CxHashKey CX_HASH_KEY(cxmutstr str) {
    return cx_hash_key_mutstr(str);
}
 
CX_CPPDECL CxHashKey CX_HASH_KEY(const char *str) {
    return cx_hash_key_str(str);
}
 
CX_CPPDECL CxHashKey CX_HASH_KEY(const unsigned char *str) {
    return cx_hash_key_ustr(str);
}
 
CX_CPPDECL CxHashKey CX_HASH_KEY(uint32_t key) {
    return cx_hash_key_u32(key);
}
 
CX_CPPDECL CxHashKey CX_HASH_KEY(uint64_t key) {
    return cx_hash_key_u64(key);
}
#endif
 
#endif // UCX_HASH_KEY_H