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[CRT] Massively improve performance of rand_s 

Cache the pointer to RtlGenRandom instead of loading and unloading advapi32 every single time this function is called.
This commit is contained in:
Timo Kreuzer 2024-04-19 20:53:51 +03:00
parent 3c55252828
commit 1f49173f82
1 changed files with 29 additions and 21 deletions
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50
sdk/lib/crt/stdlib/rand_s.c
View File

@ -9,12 +9,14 @@
#include <precomp.h>
typedef BOOLEAN (WINAPI *PFN_SystemFunction036)(PVOID, ULONG); // RtlGenRandom
PFN_SystemFunction036 g_pfnSystemFunction036 = NULL;
/*********************************************************************
* rand_s (MSVCRT.@)
*/
int CDECL rand_s(unsigned int *pval)
{
BOOLEAN (WINAPI *pSystemFunction036)(PVOID, ULONG); // RtlGenRandom
HINSTANCE hadvapi32;
if (!pval)
@ -25,32 +27,38 @@ int CDECL rand_s(unsigned int *pval)
}
*pval = 0;
hadvapi32 = LoadLibraryA("advapi32.dll");
if (!hadvapi32)
if (g_pfnSystemFunction036 == NULL)
{
PFN_SystemFunction036 pSystemFunction036;
hadvapi32 = LoadLibraryA("advapi32.dll");
if (!hadvapi32)
{
_invalid_parameter(NULL,_CRT_WIDE("rand_s"),_CRT_WIDE(__FILE__),__LINE__, 0);
*_errno() = EINVAL;
return EINVAL;
}
pSystemFunction036 = (void*)GetProcAddress(hadvapi32, "SystemFunction036");
if (!pSystemFunction036)
{
_invalid_parameter(NULL,_CRT_WIDE("rand_s"),_CRT_WIDE(__FILE__),__LINE__, 0);
*_errno() = EINVAL;
FreeLibrary(hadvapi32);
return EINVAL;
}
g_pfnSystemFunction036 = pSystemFunction036;
}
if (!g_pfnSystemFunction036(pval, sizeof(*pval)))
{
_invalid_parameter(NULL,_CRT_WIDE("rand_s"),_CRT_WIDE(__FILE__),__LINE__, 0);
*_errno() = EINVAL;
return EINVAL;
}
pSystemFunction036 = (void*)GetProcAddress(hadvapi32, "SystemFunction036");
if (!pSystemFunction036)
{
_invalid_parameter(NULL,_CRT_WIDE("rand_s"),_CRT_WIDE(__FILE__),__LINE__, 0);
*_errno() = EINVAL;
FreeLibrary(hadvapi32);
return EINVAL;
}
if (!pSystemFunction036(pval, sizeof(*pval)))
{
_invalid_parameter(NULL,_CRT_WIDE("rand_s"),_CRT_WIDE(__FILE__),__LINE__, 0);
*_errno() = EINVAL;
FreeLibrary(hadvapi32);
return EINVAL;
}
FreeLibrary(hadvapi32);
return 0;
}