Cool_Tools/imgui
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Use native crc32 on x86 if available.

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This commit is contained in:
Teselka 2024-11-20 13:10:36 +02:00
parent eb0ad66d88
commit ab315db6bf
2 changed files with 22 additions and 0 deletions
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18
imgui.cpp
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@ -2149,6 +2149,7 @@ void ImFormatStringToTempBufferV(const char** out_buf, const char** out_buf_end,
}
}
#ifndef IMGUI_ENABLE_SSE4_2
// CRC32 needs a 1KB lookup table (not cache friendly)
// Although the code to generate the table is simple and shorter than the table itself, using a const table allows us to easily:
// - avoid an unnecessary branch/memory tap, - keep the ImHashXXX functions usable by static constructors, - make it thread-safe.
@ -2171,6 +2172,7 @@ static const ImU32 GCrc32LookupTable[256] =
0xA00AE278,0xD70DD2EE,0x4E048354,0x3903B3C2,0xA7672661,0xD06016F7,0x4969474D,0x3E6E77DB,0xAED16A4A,0xD9D65ADC,0x40DF0B66,0x37D83BF0,0xA9BCAE53,0xDEBB9EC5,0x47B2CF7F,0x30B5FFE9,
0xBDBDF21C,0xCABAC28A,0x53B39330,0x24B4A3A6,0xBAD03605,0xCDD70693,0x54DE5729,0x23D967BF,0xB3667A2E,0xC4614AB8,0x5D681B02,0x2A6F2B94,0xB40BBE37,0xC30C8EA1,0x5A05DF1B,0x2D02EF8D,
};
#endif
// Known size hash
// It is ok to call ImHashData on a string with known length but the ### operator won't be supported.
@ -2179,10 +2181,16 @@ ImGuiID ImHashData(const void* data_p, size_t data_size, ImGuiID seed)
{
ImU32 crc = ~seed;
const unsigned char* data = (const unsigned char*)data_p;
#ifndef IMGUI_ENABLE_SSE4_2
const ImU32* crc32_lut = GCrc32LookupTable;
while (data_size-- != 0)
crc = (crc >> 8) ^ crc32_lut[(crc & 0xFF) ^ *data++];
return ~crc;
#else
while (data_size-- != 0)
crc = _mm_crc32_u8(crc, *data++);
return ~crc;
#endif
}
// Zero-terminated string hash, with support for ### to reset back to seed value
@ -2196,7 +2204,9 @@ ImGuiID ImHashStr(const char* data_p, size_t data_size, ImGuiID seed)
seed = ~seed;
ImU32 crc = seed;
const unsigned char* data = (const unsigned char*)data_p;
#ifndef IMGUI_ENABLE_SSE4_2
const ImU32* crc32_lut = GCrc32LookupTable;
#endif
if (data_size != 0)
{
while (data_size-- != 0)
@ -2204,7 +2214,11 @@ ImGuiID ImHashStr(const char* data_p, size_t data_size, ImGuiID seed)
unsigned char c = *data++;
if (c == '#' && data_size >= 2 && data[0] == '#' && data[1] == '#')
crc = seed;
#ifndef IMGUI_ENABLE_SSE4_2
crc = (crc >> 8) ^ crc32_lut[(crc & 0xFF) ^ c];
#else
crc = _mm_crc32_u8(crc, c);
#endif
}
}
else
@ -2213,7 +2227,11 @@ ImGuiID ImHashStr(const char* data_p, size_t data_size, ImGuiID seed)
{
if (c == '#' && data[0] == '#' && data[1] == '#')
crc = seed;
#ifndef IMGUI_ENABLE_SSE4_2
crc = (crc >> 8) ^ crc32_lut[(crc & 0xFF) ^ c];
#else
crc = _mm_crc32_u8(crc, c);
#endif
}
}
return ~crc;

4
imgui_internal.h
View File

@ -61,6 +61,10 @@ Index of this file:
#if (defined __SSE__ || defined __x86_64__ || defined _M_X64 || (defined(_M_IX86_FP) && (_M_IX86_FP >= 1))) && !defined(IMGUI_DISABLE_SSE)
#define IMGUI_ENABLE_SSE
#include <immintrin.h>
#if defined __AVX__ || defined __SSE4_2__
#define IMGUI_ENABLE_SSE4_2
#include <nmmintrin.h>
#endif
#endif
// Visual Studio warnings