8ff6e53833
There was a logic error in #7815 which made Variant.hash_compare() == Variant.hash_compare() always true. In an attempt to short-circuit the NaN check I made an (in hindsight) obvious error: 10 == 12 || is_nan(10) == is_nan(12) This will be true for all inputs, except for the NaN, not-NaN case. The macro has been updated to now generate: (10 == 12) || (is_nan(10) && is_nan(10)) so: (10 == 12) || (is_nan(10) && is_nan(12)) = false False or (False and False) is False (10 == 10) || (is_nan(10) && is_nan(10)) = true True or (False and False) is True (Nan == 10) || (is_nan(NaN) && is_nan(10)) = false False or (True and False) is False (Nan == Nan) || (is_nan(NaN) && is_nan(NaN)) = true False or (True and True) is True Which is correct for all cases. This bug was triggered because the hash function for floating point numbers can very easily generate collisions for the tested Vector3(). I've also added an extra hashing step to the float hash function to make this less likely to occur. This fixes #8081 and probably many more random weirdness.
132 lines
4 KiB
C++
132 lines
4 KiB
C++
/*************************************************************************/
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/* hashfuncs.h */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* http://www.godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md) */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#ifndef HASHFUNCS_H
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#define HASHFUNCS_H
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#include "math_defs.h"
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#include "math_funcs.h"
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#include "typedefs.h"
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/**
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* Hashing functions
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*/
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/**
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* DJB2 Hash function
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* @param C String
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* @return 32-bits hashcode
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*/
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static inline uint32_t hash_djb2(const char *p_cstr) {
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const unsigned char *chr = (const unsigned char *)p_cstr;
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uint32_t hash = 5381;
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uint32_t c;
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while ((c = *chr++))
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hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
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return hash;
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}
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static inline uint32_t hash_djb2_buffer(const uint8_t *p_buff, int p_len, uint32_t p_prev = 5381) {
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uint32_t hash = p_prev;
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for (int i = 0; i < p_len; i++)
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hash = ((hash << 5) + hash) + p_buff[i]; /* hash * 33 + c */
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return hash;
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}
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static inline uint32_t hash_djb2_one_32(uint32_t p_in, uint32_t p_prev = 5381) {
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return ((p_prev << 5) + p_prev) + p_in;
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}
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static inline uint32_t hash_one_uint64(const uint64_t p_int) {
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uint64_t v = p_int;
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v = (~v) + (v << 18); // v = (v << 18) - v - 1;
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v = v ^ (v >> 31);
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v = v * 21; // v = (v + (v << 2)) + (v << 4);
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v = v ^ (v >> 11);
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v = v + (v << 6);
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v = v ^ (v >> 22);
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return (int)v;
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}
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static inline uint32_t hash_djb2_one_float(double p_in, uint32_t p_prev = 5381) {
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union {
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double d;
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uint64_t i;
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} u;
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// Normalize +/- 0.0 and NaN values so they hash the same.
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if (p_in == 0.0f)
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u.d = 0.0;
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else if (Math::is_nan(p_in))
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u.d = Math_NAN;
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else
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u.d = p_in;
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return ((p_prev << 5) + p_prev) + hash_one_uint64(u.i);
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}
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template <class T>
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static inline uint32_t make_uint32_t(T p_in) {
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union {
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T t;
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uint32_t _u32;
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} _u;
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_u._u32 = 0;
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_u.t = p_in;
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return _u._u32;
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}
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static inline uint64_t hash_djb2_one_64(uint64_t p_in, uint64_t p_prev = 5381) {
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return ((p_prev << 5) + p_prev) + p_in;
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}
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template <class T>
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static inline uint64_t make_uint64_t(T p_in) {
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union {
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T t;
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uint64_t _u64;
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} _u;
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_u._u64 = 0; // in case p_in is smaller
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_u.t = p_in;
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return _u._u64;
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}
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#endif
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