ladybird/Kernel/Devices/NullDevice.cpp
Andreas Kling 1b2ef8582c Kernel: Make File's can_read/can_write take a const FileDescription&
Asking a File if we could possibly read or write it will never mutate
the asking FileDescription&, so it should be const.
2019-11-04 14:03:14 +01:00

36 lines
558 B
C++

#include "NullDevice.h"
#include <AK/StdLibExtras.h>
#include <AK/kstdio.h>
static NullDevice* s_the;
NullDevice& NullDevice::the()
{
ASSERT(s_the);
return *s_the;
}
NullDevice::NullDevice()
: CharacterDevice(1, 3)
{
s_the = this;
}
NullDevice::~NullDevice()
{
}
bool NullDevice::can_read(const FileDescription&) const
{
return true;
}
ssize_t NullDevice::read(FileDescription&, u8*, ssize_t)
{
return 0;
}
ssize_t NullDevice::write(FileDescription&, const u8*, ssize_t buffer_size)
{
return min(PAGE_SIZE, buffer_size);
}