ReadProcessMemory

Reads data from an area of memory in a specified process. The entire area to be read must be accessible or the operation fails.

Parameters

hProcess

[in] A handle to the process with memory that is being read. The handle must have PROCESS_VM_READ access to the process.

lpBaseAddress

[in] A pointer to the base address in the specified process from which to read. Before any data transfer occurs, the system verifies that all data in the base address and memory of the specified size is accessible for read access, and if it is not accessible the function fails.

lpBuffer

[out] A pointer to a buffer that receives the contents from the address space of the specified process.

nSize

[in] The number of bytes to be read from the specified process.

lpNumberOfBytesRead

[out] A pointer to a variable that receives the number of bytes transferred into the specified buffer. If lpNumberOfBytesRead is NULL, the parameter is ignored.

Return Value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is 0 (zero). To get extended error information, call GetLastError.

The function fails if the requested read operation crosses into an area of the process that is inaccessible.

WriteProcessMemory

Writes data to an area of memory in a specified process. The entire area to be written to must be accessible or the operation fails.

Parameters

hProcess

[in] A handle to the process memory to be modified. The handle must have PROCESS_VM_WRITE and PROCESS_VM_OPERATION access to the process.

lpBaseAddress

[in] A pointer to the base address in the specified process to which data is written. Before data transfer occurs, the system verifies that all data in the base address and memory of the specified size is accessible for write access, and if it is not accessible, the function fails.

lpBuffer

[in] A pointer to the buffer that contains data to be written in the address space of the specified process.

nSize

[in] The number of bytes to be written to the specified process.

lpNumberOfBytesWritten

[out] A pointer to a variable that receives the number of bytes transferred into the specified process. This parameter is optional. If lpNumberOfBytesWritten is NULL, the parameter is ignored.

Return Value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is 0 (zero). To get extended error information, call GetLastError. The function fails if the requested write operation crosses into an area of the process that is inaccessible.

相信上面这些都很容易看明白吧？一个用于取出数据，一个用于写入数据。
下面以星际争霸的矿石修改为例，简述这两个函数的用法。

先获取当前的矿石数，用ReadProcessMemory

ReadProcessMemory(h, ptr(GoldA + i * 4), @Gold, 4, tt);

h是程序进程的句柄，其中GoldA就是地址偏移基准数值，@Gold是一个byte型的数组buffer，读取到的数据也就存放在里面，接下来的4表示buffer的长度，最后的tt是传出值，它显示了成功读取的长度。

好了，现在读取到了，我们把@Gold的值进行一番修改后，再写回去，使用WriteProcessMemory方法

WriteProcessMemory(h, ptr(GoldA + i * 4), @Gold, 4, tt);

与上面的Read过程一模一样，这样就能够写回去了。

下面附上一段完整代码：

procedure TFormMain.Cheat113;
var
hw: HWND;
pid: DWord;
h: THandle;
tt: Cardinal;
Gold: array[0..3] of byte;
Gas: array[0..3] of byte;
GoldA: integer;
GasA: integer;
i: integer;
const
Gold130 = $508600;
Gas130 = $508630;
begin
hw := FindWindow(nil, 'Brood War');
if hw = 0 then
Exit;
GetWindowThreadProcessId(hw, @pid);
h := OpenProcess(PROCESS_ALL_ACCESS, false, pid);
if h = 0 then
Exit;
Gold[0] := $FF;
Gold[1] := $FF;
Gold[2] := $00;
Gold[3] := $00;
Gas[0] := $FF;
Gas[1] := $FF;
Gas[2] := $00;
Gas[3] := $00;
GoldA := Gold130;
GasA := Gas130;
if (chkMineral.Enabled) and (chkMineral.Checked) then
begin
for i := 0 to 11 do
begin
WriteProcessMemory(h, ptr(GoldA + i * 4), @Gold, 4, tt);
end;
end;
if (chkGas.Enabled) and (chkGas.Checked) then
begin
for i := 0 to 11 do
begin
WriteProcessMemory(h, ptr(GasA + i * 4), @Gas, 4, tt);
end;
end;
CloseHandle(h);
end;