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#pragma once
#include <windows.h>
#include <cstdint>
#include <future>
#define MEMORY_SLOT_SIZE 64
namespace memory
{
namespace instructions
{
// we're dealing with opcodes, align by 1 byte
#pragma pack(push, 1)
struct short_jump_t
{
uint8_t opcode{ };
uint8_t operand{ };
};
struct long_jump_t
{
uint8_t opcode{ };
uint32_t operand{ };
};
struct short_patch_t
{
long_jump_t jmp{ };
short_jump_t jmp_short{ };
};
struct JCC_REL
{
uint8_t opcode0{ };
uint8_t opcode1{ };
uint32_t operand{ };
};
#pragma pack(pop)
}
struct detour_hook_t
{
bool enabled{ };
bool short_patch{ };
uintptr_t m_original{ };
uintptr_t m_custom{ };
uintptr_t m_trampoline{ };
uint8_t m_original_bytes[8]{ };
bool allocate_trampoline( )
{
if ( m_trampoline )
return false;
m_trampoline = (uintptr_t)VirtualAlloc( nullptr, MEMORY_SLOT_SIZE, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE );
memset( (void*)m_trampoline, 0, MEMORY_SLOT_SIZE );
return m_trampoline;
}
void restore( )
{
if ( m_trampoline )
{
VirtualFree( (void*)m_trampoline, MEMORY_SLOT_SIZE, MEM_RELEASE );
m_trampoline = 0;
}
}
};
class c_detours
{
std::vector<detour_hook_t> m_hooks;
static bool create_trampoline( detour_hook_t* hook );
detour_hook_t* find_hook( uintptr_t custom_func )
{
detour_hook_t* hook = nullptr;
for ( auto& m_hook : m_hooks )
{
if ( m_hook.m_custom == custom_func )
{
return &m_hook;
}
}
return nullptr;
}
bool set_hook( detour_hook_t* hook, bool enable );
bool set_hook( uintptr_t custom_func, bool enable )
{
detour_hook_t* hook = find_hook( custom_func );
if ( hook )
return set_hook( hook, enable );
return false;
}
public:
template < typename fn = uintptr_t >
fn create_hook( fn custom_func, void* original_func )
{
detour_hook_t hook;
hook.m_original = uintptr_t( original_func );
hook.m_custom = intptr_t( custom_func );
if ( create_trampoline( &hook ) )
{
if ( hook.short_patch )
memcpy( hook.m_original_bytes, (void*)( hook.m_original - sizeof( instructions::long_jump_t ) ), sizeof( instructions::short_patch_t ) );
else
memcpy( hook.m_original_bytes, (void*)( hook.m_original ), sizeof( instructions::long_jump_t ) );
#ifdef _DEBUG
printf( " $> prepared hook [ original: 0x%08x ] [ custom: 0x%08x ] [ short jmp: %d ] \n", uintptr_t( original_func ), uintptr_t( custom_func ), hook.short_patch );
#endif
m_hooks.push_back( hook );
return (fn)hook.m_trampoline;
}
#ifdef _DEBUG
printf( " $> FAILED TO HOOK [ original: 0x%08x ] [ custom: hook 0x%08x ] \n", uintptr_t( original_func ), uintptr_t( custom_func ) );
#endif
return (fn)0;
}
void enable( )
{
for ( auto& hook : m_hooks )
set_hook( &hook, true );
}
void restore( )
{
for ( auto& hook : m_hooks )
{
set_hook( &hook, false );
hook.restore( );
}
m_hooks.clear( );
}
template < typename fn = uintptr_t >
fn original( void* custom_func )
{
auto hook = find_hook( (uintptr_t)custom_func );
if ( hook )
return (fn)hook->m_trampoline;
return (fn)0;
}
}; extern c_detours detours;
}
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