gmcl_samurai_win32

This module allows you to call __stdcall/__cdecl functions by pointer from Lua

Functions:

handle = samurai.GetModuleHandle("user32.dll") - Get DLL HMODULE (return value caster to number)

func = samurai.GetProcAddress(handle,"MessageBoxA") - GetProcAddress, handle is a number (32 bit)

api = samurai.ExportTable("ntdll.dll") - Walks through dll's export table and pushes function in returned table

obj = samurai.Alloc(size) - Allocate memory, returns memobj metatable

stc = samurai.StructFromPointer(ptr) - Makes a struct metatable, ptr is a pointer (casted to number)

n = invoke(FuncPointer,...) - Call __cdecl/__stdcall by pointer (number), return value is integer, stored in eax (aka func's return value)

MemObj Metatable:

You can get this object by samurai.Alloc(n)

obj = samurai.Alloc(292)

Metamethods

obj:Free() - Free allocated memory

obj:ToString() - Returns memory as string

obj:ToStruct() - Returns struct metatable

obj:ToPointer() - Returns mem ptr as number

Struct Metatable:

You can get this object by casting from memobj

stc = obj:ToStruct()

Or by casting from pointer

stc = samurai.StructFromPointer(ptr)

Struct organized as stack, which start from mem ptr

Metamethods

stc:ResetPtr() - Reset s_ptr (aka stack pointer) to default value (mem ptr)

n = stc:GetOffset() - Get length from s_ptr and mem ptr, aka struct offset

stc:SetOffset(n) - Directly set stack pointer (s_ptr = mem ptr + offset)

stc:Skip(n) - Skip n bytes, add to offset n

stc:PushString(str) - Write string to s_ptr and add offset - string len + 1

stc:PushNumber(sz,n) - Which sz is (BYTE/WORD/DWORD) and n - number; Write number and his length to offset

str = stc:GetStringFromPtr() - return string by pointer from s_ptr and add 4 (DWORD size) to offset (aka char*)

str = stc:GetStringFixed(sz) - returns string from s_ptr and add to offset sz (string with fixed size aka char str[256])

str = stc:GetString() - Same as GetStringFixed, but sz is = strlen(str) (aka char str[?])

n = stc:GetNumber(sz) - Return number at s_ptr and add to offset sz (which BYTE/WORD/DWORD)

ptr = stc:ToPointer() - Return mem ptr

Practical usage

You need set struct like this

typedef struct {
  int a;
  int b;
  int c
} something_t;

just

mem = samurai.Alloc(12) -- sizeof(int)*3
stc = mem:ToStruct()
stc:ResetPtr()
stc:PushNumber(DWORD,1)
stc:PushNumber(DWORD,2)
stc:PushNumber(DWORD,3)

--Or parse

a = stc:GetNumber(DWORD)
b = stc:GetNumber(DWORD)
c = stc:GetNumber(DWORD)

mem:Free() -- Don't forget to free memory!

Global

When module loading, in global table (_G), samurai makes a few tables: kernel32,user32

Which filled by function pointers from kernel32.dll and user32.dll

n = invoke(FuncPointer,...) - Call __cdecl/__stdcall by pointer (number), return value is integer, stored in eax (aka func's return value)

Some global values:

NULL = 0
BYTE = 1
WORD = 2
DWORD = 4

Post Scriptum

See example in inject.lua

Also this module writed with custom lua interface (see in repo gmcl_jack_win32)