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0b3496fb4f
Made possible by EIREXE, xsellier and the SDL team. This commit includes statically linked SDL3 for Windows, Linux and macOS. The vendored copy of SDL3 was setup to only build the required subsystems for gamepad/joystick support, with some patches to be able to make it as minimal as possible and reduce the impact on binary size and code size. Co-authored-by: Álex Román Núñez <eirexe123@gmail.com> Co-authored-by: Xavier Sellier <xsellier@gmail.com> Co-authored-by: Rémi Verschelde <rverschelde@gmail.com>
87 lines
2.7 KiB
C
87 lines
2.7 KiB
C
/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#include "SDL_internal.h"
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// Public domain murmur3 32-bit hash algorithm
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//
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// Adapted from: https://en.wikipedia.org/wiki/MurmurHash
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static SDL_INLINE Uint32 murmur_32_scramble(Uint32 k)
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{
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k *= 0xcc9e2d51;
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k = (k << 15) | (k >> 17);
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k *= 0x1b873593;
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return k;
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}
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Uint32 SDLCALL SDL_murmur3_32(const void *data, size_t len, Uint32 seed)
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{
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const Uint8 *bytes = (const Uint8 *)data;
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Uint32 hash = seed;
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Uint32 k;
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// Read in groups of 4.
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if ((((uintptr_t)bytes) & 3) == 0) {
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// We can do aligned 32-bit reads
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for (size_t i = len >> 2; i--; ) {
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k = *(const Uint32 *)bytes;
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k = SDL_Swap32LE(k);
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bytes += sizeof(Uint32);
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hash ^= murmur_32_scramble(k);
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hash = (hash << 13) | (hash >> 19);
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hash = hash * 5 + 0xe6546b64;
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}
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} else {
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for (size_t i = len >> 2; i--; ) {
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SDL_memcpy(&k, bytes, sizeof(Uint32));
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k = SDL_Swap32LE(k);
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bytes += sizeof(Uint32);
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hash ^= murmur_32_scramble(k);
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hash = (hash << 13) | (hash >> 19);
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hash = hash * 5 + 0xe6546b64;
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}
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}
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// Read the rest.
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size_t left = (len & 3);
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if (left) {
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k = 0;
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for (size_t i = left; i--; ) {
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k <<= 8;
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k |= bytes[i];
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}
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// A swap is *not* necessary here because the preceding loop already
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// places the low bytes in the low places according to whatever endianness
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// we use. Swaps only apply when the memory is copied in a chunk.
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hash ^= murmur_32_scramble(k);
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}
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/* Finalize. */
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hash ^= len;
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hash ^= hash >> 16;
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hash *= 0x85ebca6b;
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hash ^= hash >> 13;
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hash *= 0xc2b2ae35;
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hash ^= hash >> 16;
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return hash;
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}
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